Description:FIELD OF THE INVENTION
[0001] The present invention relates to powertrains of automobiles. More specifically, the present invention pertains to a hybrid electric drive system for a vehicle that optimizes the integration of two independent drives, such as an Internal Combustion (IC) engine and an electric powertrain. The hybrid electric drive system is configured to function on rear-wheel drive, front-wheel drive, four-wheel drive, or all-wheel drive vehicles, both on-road and off-road vehicles, including farm equipment vehicles.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The increasing global demand for energy-efficient and environmentally friendly transportation solutions has prompted a significant shift in the automotive industry. Traditional internal combustion (IC) engine-powered vehicles have been major contributors to environmental pollution, primarily due to their reliance on fossil fuels, which emit harmful greenhouse gases (GHGs) and other pollutants into the atmosphere. The negative impact of these emissions on both global climate change and public health has created an urgent need to develop alternative powertrain technologies that can reduce such emissions. Urban vehicular emissions not only contribute to global temperature rise and climate change but also affect the health of urban populations, who inhale these harmful emissions, leading to health hazards such as early deaths and chronic obstructive pulmonary disease (COPD).
[0004] In response to this challenge, hybrid and electric vehicle technologies have been rapidly advancing. Electric vehicles (EVs) are often touted as a key solution to reduce vehicular emissions and mitigate the effects of climate change. These vehicles rely solely on electric motors powered by batteries, eliminating tailpipe emissions entirely. However, electric vehicles are not without their own set of challenges, including limited range, long recharging times, and insufficient charging infrastructure, which have contributed to consumer hesitance to fully embrace EVs.
[0005] There is strong scientific evidence and a record of health hazards and ailments that need to be addressed with urgency. This requires providing more practical solutions for sustainable mobility that reduce harmful emissions. At the same time, consumers in the automobile sector are accustomed to certain conveniences, such as ease of fuelling, long range on a full tank, and specific driving features. These conveniences cannot be abruptly removed by switching to renewable energy-based vehicles, such as fully electric vehicles, which currently fall short in terms of features and convenience, considering the mass affordability factor. Fully electric vehicles have several shortcomings, including long recharge times, a lack of adequate charging facilities, and range anxiety for drivers and passengers due to their relatively short range on a single charge.
[0006] On the other hand, hybrid vehicles, which combine an internal combustion engine with an electric motor, have gained popularity as a compromise between traditional IC engine-based vehicles and fully electric vehicles. By integrating both powertrains, hybrid vehicles can offer improved fuel efficiency, reduced emissions, and extended driving range compared to fully electric vehicles.
[0007] To address the aforementioned challenges of mobility, a more flexible and efficient hybrid electric drive system is required, one that optimizes the integration of the electric and IC engine powertrains for different driving conditions while ensuring a seamless transition between the two drive modes (electric and combustion engine). This system would maximize performance, fuel efficiency, and the overall driving experience. The hybrid electric drive system should be adaptable to various vehicle configurations and provide improved sustainability while maintaining user conveniences, such as long driving range, ease of fuelling/recharging, and low operating costs. There is also a need for a hybrid electric drive system that offers a practical solution to the limitations of current hybrid and electric vehicle technologies. This includes the ability to offer configurations for both on-road and off-road vehicles, provide enhanced performance across multiple drive modes, reduce greenhouse gas emissions, and address consumer preferences for convenience, all while remaining cost-effective and adaptable to a wide variety of vehicle platforms.
[0008] Using the present invention, Original Equipment Manufacturers (OEMs) can either manufacture new Plug-In Hybrid Vehicle (PHEV) or Fuel Cell Electric Hybrid Vehicle (FC-HEV) variants of their existing IC engine-based vehicles in their portfolios or promote retrofit conversion solutions through their authorized service/dealer network. Both options offer substantial additional revenue opportunities, besides leading to significantly higher green miles and better Corporate Average Fuel Economy (CAFE) regulatory compliance. On a national level, the resulting savings from reduced fossil fuel imports and the consequential benefits to the national economy provide a huge advantage. The present invention can also be highly beneficial for consumers because it offers the opportunity to recover a substantial portion of the vehicle’s initial cost due to reduced operating costs over its lifespan. Furthermore, as employment in the IC engine supply chain is retained and can be further expanded in ICE, EV, and FCEV supply chains, this invention is extremely inclusive for the economy. Thus, the present invention would be a win-win solution for all stakeholders, including government, OEMs, consumers, the economy, and the environment, areas in which we all share common interests.

OBJECTS OF THE PRESENT DISCLOSURE
[0009] Some of the objects of the present disclosure, which at least one embodiment herein satisfies are as listed herein below.
[0010] It is an object of the present invention to provide a hybrid electric drive for an internal combustion (IC) engine-based vehicle, which incorporates a hybrid electric drive system. This system comprises an electric motor, an innovatively designed over-running clutch drive unit, and a smart programmable chip-based microcontroller, which uniquely regulates the transfer and modulation of torque generated by both the IC engine and the electric motor to a common drive shaft (propeller shaft) of the vehicle. The hybrid electric drive system is mounted between the gearbox assembly coupled to the IC engine and the final axle drive of the vehicle. This configuration enables a faster and simpler conversion method for converting IC engine-driven vehicle architectures to hybrid electric vehicles.
[0011] It is another object of the present invention to provide a hybrid electric drive system that allows a user to easily control the mode of operation of the vehicle in zero-emission zones within urban areas.
[0012] It is another object of the present invention to develop a hybrid electric drive system for an IC engine-driven vehicle architecture that serves as a simple, manufacturer-friendly, and labour-friendly production alternative to existing well-known IC engine vehicle architectures.
[0013] It is another object of the present invention to simplify the installation of an electric drive assembly, comprising components such as the hybrid electric drive system, which includes the innovatively designed over-running clutch drive unit, the smart programmable chip-based microcontroller, and the electric motor, onto an existing IC engine vehicle architecture with minimal modifications to the existing design and assembly process. This enables manufacturers to use existing assembly lines with minimal changes, thereby reducing both design and manufacturing costs.
[0014] It is another object of the present invention to simplify the installation of an electric drive assembly, comprising components such as the hybrid electric drive system with the over-running clutch drive unit, the smart programmable chip-based microcontroller, and the electric motor, onto an existing IC engine vehicle with minimal modifications, facilitating easy and modular retrofit solutions for existing vehicles.
[0015] It is another object of the present invention to create a single, bolt-on hybrid electric drive system, comprising components such as the innovatively designed over-running clutch drive unit, the smart programmable chip-based microcontroller, the electric motor, and input and output drive shafts (propeller shafts). This system forms a modular unit known as the “e-propeller,” allowing easy substitution of the existing propeller shaft in an IC engine vehicle with the modular “e-propeller.” This solution enables manufacturers to use existing assembly lines with minimal additions or substitutions, keeping both design and manufacturing costs low. Additionally, it allows for easy and quick retrofit of existing vehicles using this modular “e-propeller” hybrid electric drive unit.
[0016] It is another object of the present invention to create a single, bolt-on hybrid electric drive system, comprising components such as the innovatively designed over-running clutch drive unit, the smart programmable chip-based microcontroller, the electric motor, input and output drive shafts (propeller shafts) and the driven axle with differential. This system forms a modular unit known as the “hybrid e-axle,” allowing easy substitution of the existing propeller shaft and driven axle in an IC engine vehicle with the modular “hybrid e-axle.” This solution enables manufacturers to use existing assembly lines with minimal additions or substitutions, keeping both design and manufacturing costs low.
[0017] It is yet another object of the present invention to combine the IC engine and the electric drive assembly, synchronizing the torque generated by each, in a way that utilizes the specific torque-speed characteristics of both the IC engine and the electric motor. This enables highly efficient, low-emission, and low-fuel-consumption operation of the combined powertrain.
[0018] It is still another object of the present invention to provide a hybrid electric drive system configured in such a way that it can easily be mounted between the IC engine and its gearbox assembly in vehicle applications where space constraints exist, such as in certain front-wheel-drive passenger vehicles.

SUMMARY
[0019] The present invention relates to powertrain technology that optimizes the integration of two independent drives, such as an internal combustion (IC) engine and electric powertrains, on a vehicle. In particular, the present invention relates to a hybrid electric drive system for a vehicle that offers a range of hybrid powertrain solutions, including IC engine and electric Plug-In Hybrid Vehicle (PHEV) architectures, IC engine and Fuel Cell Electric Hybrid Vehicle (FC-HEV) architectures, and other permutations and combinations of powertrains. The fuel-agnostic nature of the present invention offers optimum sustainable mobility solutions for all categories of vehicles.
[0020] The hybrid electric drive system efficiently optimizes the integration of two independent powertrains, such as an IC engine and an electric motor, and is designed to function efficiently across different drive configurations, including rear-wheel drive, front-wheel drive, all-wheel drive, and four-wheel drive vehicles. The hybrid electric drive system can be implemented in a broad range of vehicles, including passenger vehicles, commercial vehicles, and off-road equipment. This hybrid electric drive system introduces a new level of flexibility and efficiency, ensuring sustainable mobility without compromising on performance, range, or the user experience that consumers expect from modern vehicles. Additionally, the hybrid electric drive system combines the strengths of both electric and internal combustion technologies to deliver improved fuel economy, reduced emissions, and a more sustainable and versatile approach to transportation.
[0021] The hybrid electric drive system enables a faster and simpler conversion method for converting IC engine-driven vehicle architectures into Hybrid Electric Vehicles (HEVs). With the increasing pace of development in green hydrogen-producing technologies, the use of hydrogen fuel cell stacks to power the electric powertrain in such an HEV may also be facilitated by the hybrid electric drive system. Such Fuel Cell Hybrid Electric Vehicles (FC-HEVs) could provide a strong and alternative sustainable mobility solution.
[0022] In an aspect of the present disclosure, the present disclosure relates to a hybrid electric drive system (interchangeably known as “Hybrid Drive System”, “HDS” or “system” herein) for a vehicle. The vehicle includes an IC engine assembly configured to drive a set of wheels of the vehicle in an engine mode of operation, and an electric motor configured to drive the set of wheels in an electric mode of operation. The system includes an over-running clutch drive unit (also interchangeably referred to as “clutch unit” herein) arranged between a gearbox of the IC engine assembly and a differential mounted on a driven axle driving the set of wheels. The over-running clutch drive unit is configured to control supply of the rotary power generated by the IC engine assembly and the electric motor to the set of wheels in each of the engine mode of operation, the electric mode of operation, and a combined mode of operation. The clutch unit, in the combined mode of operation, supplies a combined rotary power generated by both the IC engine assembly and the electric motor to the set of wheels
[0023] The clutch unit includes an outer hub assembly configured to receive the rotary power generated by the electric motor. The outer hub assembly is rotatably coupled to a propeller shaft adapted to drive the set of wheels. The clutch unit includes a main coupler hub assembly mounted on a drive shaft adapted to receive the rotary power generated by the IC engine assembly, a first cam plate fixedly coupled with the outer hub assembly, a second cam plate fixedly coupled with the drive shaft. The clutch unit also includes a first set of rollers and springs configured with one or more recesses of the first cam plate to regulate linkage between the first cam plate and the main coupler hub assembly, a second set of rollers and springs configured with one or more recesses of the second cam plate to regulate the linkage between the second cam plate and the main coupler hub assembly. The clutch unit also includes a shaft coupler to regulate transmission of the rotary power from the drive shaft directly to the propeller shaft, in a reverse mode of operation.
[0024] The system also includes a controller operatively connected to a motor controller configured with the electric motor to regulate generation of rotary power by the electric motor. The controller is configured to maintain rotational speed of the outer hub assembly to be less than the rotational speed of the drive shaft driven by the IC engine assembly, during the combined mode of operation, to enable the rotary power generated by both the IC engine assembly and the electric motor to be combined and seamlessly transmitted to the propeller shaft to drive the set of wheels.
[0025] In an embodiment, the set of wheels may be mounted on an axle of the vehicle. The propeller shaft may be coupled to the axle through a differential to drive the set of wheels upon any of rotation of the main coupler hub assembly in the engine mode of operation, rotation of the outer hub assembly in the electric mode of operation, or rotation of the propeller shaft based on combination of the rotary power transmitted by the IC engine assembly and the electric motor in the combined mode of operation.
[0026] In an embodiment, the electric motor may be coupled to the outer hub assembly through a transmission member including at least one of a set of gears and a chain drive.
[0027] In an embodiment, the electric motor, the over-running clutch drive unit and the controller may be integrated together to form a single drive module mounted on a chassis of the vehicle between a gearbox of the IC engine assembly and the differential mounted on the axle coupled to the propeller shaft.
[0028] In an embodiment, the first set of rollers and springs and the second set of rollers and springs of the over-running clutch drive unit may be configured to regulate supply of the rotary power generated by the IC engine assembly and the electric motor to the set of wheels in each of the engine mode of operation, the electric mode of operation, and the combined mode of operation.
[0029] In an embodiment, the second set of rollers and springs, in the engine mode of operation, may be configured to connect the linkage between the second cam plate and the main coupler hub assembly, such that the rotary power transmitted to the drive shaft by the IC engine assembly is supplied to the main coupler hub assembly that rotates with the same speed and direction as the second cam plate.
[0030] In an embodiment, the motor controller may be configured to disable generation of the rotary power by the electric motor, in the engine mode of operation. The first set of rollers and springs may be adapted to connect the linkage between the main coupler hub assembly and the first cam plate, such that the rotary power transmitted to the main coupler hub assembly by the drive shaft is supplied to the propeller shaft through the first cam plate fixedly coupled to the outer hub assembly.
[0031] In an embodiment, the controller may be operatively connected to an Engine Control Unit (ECU) of the IC engine assembly that is configured to control generation of the rotary power from the IC engine assembly in the electric mode of operation. The motor controller may enable generation of the rotary power by the electric motor, in the electric mode of operation. At this stage, the first set of rollers and springs may be configured to disconnect the linkage between the first cam plate and the main coupler hub assembly, in the electric mode of operation. This enables the rotary power transmitted to the outer hub assembly by the electric motor to be supplied to the propeller shaft through the outer hub assembly, in the electric mode of operation, while the main coupler hub assembly remains stationary.
[0032] In an embodiment, in the combined mode of operation, the ECU may enable generation of the rotary power by the IC engine assembly, and the motor controller may enable generation of the rotary power by the electric motor. The second set of rollers and springs may be adapted to connect the linkage between the second cam plate and the main coupler hub assembly, such that the rotary power transmitted to the drive shaft by the IC engine assembly is supplied to the main coupler hub assembly that rotates with the same speed and direction as the second cam plate. Also, in the combined mode, the first set of rollers and springs may be adapted to connect the linkage between the main coupler hub assembly and the first cam plate, such that the rotary power transmitted to the main coupler hub assembly by the IC engine assembly driving the drive shaft is supplied to the first cam plate fixedly coupled to the outer hub assembly. As a result, the rotary power transmitted from the IC engine assembly to the outer hub assembly is combined/added to the rotary power transmitted from the electric motor directly to the outer hub assembly, and seamlessly transmitted to the propeller shaft to drive the set of wheels.
[0033] In an embodiment, in the reverse mode of operation, the ECU may enable generation of the rotary power by the IC engine assembly to rotate the drive shaft in a reverse direction, and the motor controller may disable generation of the rotary power by the electric motor. The second set of rollers and springs may be adapted to disconnect the linkage between the second cam plate coupled to the drive shaft and the main coupler hub assembly. Then, the shaft coupler enables direct transmission of the rotary power from the second cam plate rotating in the reverse direction to the propeller shaft.
[0034] In an embodiment, the shaft coupler may include a third cam plate fixedly coupled with the shaft coupler, and a third set of rollers and springs configured with one or more recesses of the third cam plate to regulate linkage between the shaft coupler and a hub of the drive shaft. The third set of rollers and springs may be adapted to connect the linkage between the third cam plate of the shaft coupler and the hub of the drive shaft rotating in the reverse direction. As a result, the shaft coupler, in the reverse mode of operation, enables the rotary power transmitted to the drive shaft by the IC engine assembly to be supplied to the propeller shaft that rotates with the same speed and direction as the drive shaft.
[0035] In another embodiment, the shaft coupler may be adapted to move between a retracted position and an extended position. In the retracted position, the shaft coupler prevents transmission of the rotary power from the drive shaft to the propeller shaft, when the second set of rollers and springs connects the linkage between the second cam plate and the main coupler hub assembly. The shaft coupler, in the extended position, is configured to transmit the rotary power from the drive shaft directly to the propeller shaft when the second set of rollers and springs disconnect the linkage between the second cam plate and the main coupler hub assembly.
[0036] In another aspect of the present disclosure, a hybrid electric drive system for a vehicle includes an IC engine assembly configured to drive a set of wheels of the vehicle in an engine mode of operation, an electric motor configured to drive the set of wheels in an electric mode of operation. The system includes an over-running clutch drive unit arranged between the IC engine assembly and a gearbox (also referred to as “gearbox assembly” herein) of vehicle. The clutch unit is configured to control supply of the rotary power generated by the IC engine assembly and the electric motor to the gearbox operatively coupled to the set of wheels in each of the engine mode of operation, the electric mode of operation, and a combined mode of operation. The clutch unit, in the combined mode of operation, supplies a combined rotary power generated by both the IC engine assembly and the electric motor to the gearbox to drive the set of wheels.
[0037] The over-running clutch drive unit includes a main cam plate configured to receive the rotary power generated by the electric motor. The main cam plate is rotatably coupled to a propeller shaft configured to drive the gearbox. The clutch unit also includes a main coupler hub assembly mounted on a drive shaft adapted to receive the rotary power generated by the IC engine assembly, and a set of rollers and springs configured with one or more recesses of the main cam plate to regulate linkage between the main cam plate and the main coupler hub assembly.
[0038] The system includes a controller operatively connected to a motor controller configured with the electric motor to regulate generation of rotary power by the electric motor. The controller is configured to maintain rotational speed of the main cam plate to be less than the rotational speed of the main coupler hub assembly driven by the IC engine assembly through the drive shaft, during the combined mode of operation, to enable the rotary power generated by both the IC engine assembly and the electric motor to be combined and seamlessly transmitted to the propeller shaft to drive the gearbox.
[0039] In an embodiment, the electric motor, the over-running clutch drive unit and the controller may be integrated together to form a single drive module mounted on a chassis of the vehicle between the IC engine assembly and the gearbox.
[0040] In an embodiment, the set of rollers and springs of the over-running clutch drive unit may be configured to regulate supply of the rotary power generated by the IC engine assembly and the electric motor to the gearbox driving the set of wheels in each of the engine mode of operation, the electric mode of operation, and the combined mode of operation.
[0041] In an embodiment, the motor controller may be configured to disable generation of the rotary power by the electric motor, in the engine mode of operation. At this stage, the set of rollers and springs may be adapted to connect the linkage between the main cam plate and the main coupler hub assembly. This enables the rotary power transmitted to the main coupler hub assembly by the IC engine assembly to be supplied to the main cam plate that drives the gearbox through the propeller shaft.
[0042] In an embodiment, the controller may be operatively connected to an ECU of the IC engine assembly that is configured to control generation of the rotary power from the IC engine assembly, in the electric mode of operation. The motor controller may be configured to enable generation of the rotary power by the electric motor, in the electric mode of operation, and the set of rollers and springs may be adapted to disconnect the linkage between the main cam plate and the main coupler hub assembly. This disconnection of the linkage between the main cam plate and the main coupler hub assembly enables the rotary power transmitted to the main cam plate by the electric motor to be supplied to the propeller shaft to drive the gearbox, while the main coupler hub assembly remains stationary.
[0043] In an embodiment, in the combined mode of operation, the ECU may enable generation of the rotary power by the IC engine assembly, and the motor controller may enable generation of the rotary power by the electric motor. Subsequently, the set of rollers and springs may be adapted to connect the linkage between the main cam plate and the main coupler hub assembly, such that the rotary power transmitted to the drive shaft by the IC engine assembly is supplied to the main coupler hub assembly, and the rotary power generated by the electric motor is supplied to the main cam plate. Thus, the controller maintains the rotational speed of the main cam plate driven by the electric motor to be less than the rotational speed of the main coupler hub assembly driven by the IC engine assembly to enable the rotary power generated by both the IC engine assembly and the electric motor to be combined and seamlessly transmitted to the propeller shaft to drive the gearbox.
[0044] Another aspect of the present disclosure relates to a hybrid electric drive system for a vehicle, which includes an IC engine assembly configured to drive a set of wheels of the vehicle in an engine mode of operation, an electric motor configured to drive the set of wheels in an electric mode of operation, and an over-running clutch drive unit arranged between a gearbox of the IC engine assembly and a differential mounted on a driven axle driving the set of wheels. The over-running clutch drive unit is configured to control supply of the rotary power generated by the IC engine assembly and the electric motor to the set of wheels in each of the engine mode of operation, the electric mode of operation, and a combined mode of operation.
[0045] The over-running clutch drive unit, in the combined mode of operation, supplies a combined rotary power generated by both the IC engine assembly and the electric motor to the set of wheels. The over-running clutch drive unit includes a main cam plate configured to receive the rotary power generated by the electric motor. The main cam plate is rotatably coupled to a propeller shaft adapted to drive the set of wheels. The over-running clutch drive unit also includes a main coupler hub assembly mounted on a drive shaft adapted to receive the rotary power generated by the IC engine assembly, a set of rollers and springs configured with one or more recesses of the main cam plate to regulate linkage between the first cam plate and the main coupler hub assembly, and a shaft coupler adapted to regulate transmission of the rotary power from the drive shaft directly to the propeller shaft, in a reverse mode of operation.
[0046] The hybrid electric drive system also includes a controller operatively connected to a motor controller configured with the electric motor to regulate generation of rotary power by the electric motor. The controller is configured to maintain rotational speed of the main cam plate to be less than the rotational speed of the drive shaft driven by the IC engine assembly, during the combined mode of operation, to enable the rotary power generated by both the IC engine assembly and the electric motor to be combined and seamlessly transmitted to the propeller shaft to drive the set of wheels.
[0047] In an embodiment, the propeller shaft may be coupled to the driven axle through the differential to drive the set of wheels upon any of rotation of the main coupler hub assembly in the engine mode of operation, or rotation of the main cam plate in the electric mode of operation, or rotation of the propeller shaft based on combination of the rotary power transmitted by the IC engine assembly and the electric motor in the combined mode of operation.
[0048] In an embodiment, the electric motor is coupled to the main cam plate through a transmission member including at least one of a set of gears and a chain drive.
[0049] In an embodiment, the electric motor, the over-running clutch drive unit and the controller may integrated together to form a single drive module mounted on a chassis of the vehicle between a gearbox of the IC engine assembly and the differential mounted on the driven axle coupled to the propeller shaft.
[0050] In an embodiment, the set of rollers and springs of the over-running clutch drive unit may be adapted to regulate supply of the rotary power generated by the IC engine assembly and the electric motor to the set of wheels in each of the engine mode of operation, the electric mode of operation, and the combined mode of operation.
[0051] In an embodiment, in the engine mode of operation, the motor controller may be configured to disables generation of the rotary power by the electric motor, and the set of rollers and springs may be adapted to connect the linkage between the main cam plate and the main coupler hub assembly, such that the rotary power transmitted to the main coupler hub assembly by the drive shaft is supplied to the main cam plate that drives the propeller shaft.
[0052] In an embodiment, the controller is operatively connected to an ECU of the IC engine assembly configured to control generation of the rotary power from the IC engine assembly.
[0053] In an embodiment, the motor controller may be configured to enable generation of the rotary power by the electric motor, in the electric mode of operation, and the set of rollers and springs may be adapted to disconnect the linkage between the main cam plate and the main coupler hub assembly. This enables the rotary power transmitted to the main cam plate by the electric motor to be supplied to the propeller shaft, while the main coupler hub assembly remains stationary.
[0054] In an embodiment, the ECU may be configured to enable generation of the rotary power by the IC engine assembly, in the combined mode of operation. At this stage, the motor controller may be configured to enable generation of the rotary power by the electric motor, and the set of rollers and springs may be adapted to connect the linkage between the main cam plate and the main coupler hub assembly, such that the rotary power transmitted to the drive shaft by the IC engine assembly is supplied to the main coupler hub assembly, and the rotary power generated by the electric motor is supplied to the main cam plate. The controller may be configured, in the combined mode of operation, to maintain the rotational speed of the main cam plate driven by the electric motor to be less than the rotational speed of the main coupler hub assembly driven by the IC engine assembly to enable the rotary power generated by both the IC engine assembly and the electric motor to be combined and seamlessly transmitted to the propeller shaft to drive the set of wheels.
[0055] In an embodiment, the ECU may be configured, in the reverse mode of operation, to enable generation of the rotary power by the IC engine assembly to rotate the drive shaft in a reverse direction, and the motor controller may be configured to disable generation of the rotary power by the electric motor. Subsequently, the set of rollers and springs may be adapted to disconnect the linkage between the main coupler hub assembly and the main cam plate, and the shaft coupler may be configured to directly transmit the rotary power from the drive shaft rotating in the reverse direction to the propeller shaft.
[0056] In an embodiment, the shaft coupler may include a third cam plate fixedly coupled with the shaft coupler, and a third set of rollers and springs configured with one or more recesses of the third cam plate to regulate linkage between the shaft coupler and a hub of the drive shaft. The third set of rollers and springs may be configured to connect the linkage between the third cam plate of the shaft coupler and the hub of the drive shaft rotating in the reverse direction, in the reverse mode of operation, such that the rotary power transmitted to the drive shaft by the IC engine assembly is supplied to the propeller shaft that rotates with the same speed and direction as the drive shaft.
[0057] In an embodiment, the vehicle may include a combined accelerator configured with the electric motor and the IC engine assembly to enable the electric motor to speed up earlier than the IC engine assembly owing to high initial starting torque of the electric motor, in the combined mode of operation. The combined accelerator may be configured with a configurable phase lag to allow the electric motor to speed up earlier than the IC engine, in order to take advantage of the high initial starting torque of the electric motor, while the vehicle operates in combined mode of operation.
[0058] In an embodiment, the controller may be operatively connected to the combined accelerator to enable propulsion of the vehicle by ensuring the user of the highest efficiency zones of either of the IC engine assembly and the electric motor in the combined mode of operation.
[0059] In an embodiment, in the engine mode of operation, the rotary power transmitted to the set of wheels may be supplied to the electric motor through the over-running clutch drive unit to enable a battery pack configured with electric motor to be charged, depending on State of Charge (SoC) of the battery pack.
[0060] In an embodiment, the vehicle may include a fuelling assembly having a hydrogen fuel cells stack and a liquid hydrogen tank configured to supply electrical energy to operate the electric motor, wherein the hydrogen fuel cells stack, the liquid hydrogen tank and the battery pack is mounted on the chassis of the vehicle.
[0061] In an embodiment, the electric motor may be configured to receive electrical energy from a stack of ultra-capacitors to improve reliability and availability of the electrical energy supplied to the electric motor.
[0062] In an embodiment, a vehicle includes the hybrid electric drive system. The vehicle can be a rear-wheel drive, front-wheel drive, all-wheel drive, or a four-wheel drive hybrid electric vehicle.
[0063] In an embodiment, the vehicle includes a single bolt-on hybrid electric drive system, which includes components such as the over-running clutch drive unit, the controller, the electric motor, and input and output drive shafts (propeller shafts) of the vehicle. This results in the creation of a modular “e-propeller” unit, allowing for the easy substitution of the existing propeller shaft of an IC engine-based vehicle with the modular “e-propeller” unit, while keeping the rest of the IC engine architecture of the vehicle unchanged.
[0064] In an embodiment, the vehicle includes a single bolt-on hybrid electric drive system, which includes components such as the over-running clutch drive unit, the controller, the electric motor, input and output drive shafts (propeller shafts) and driven axle with differential of the vehicle. This results in the creation of a modular “hybrid e-axle” unit, allowing for the easy substitution of the existing propeller shaft and driven axle of an IC engine-based vehicle with the modular “hybrid e-axle” unit, while keeping the rest of the IC engine architecture of the vehicle unchanged.
[0065] In an embodiment, the over-running clutch drive unit and the electric motor may be located as a single module between the IC engine and the gearbox assembly when space between the gearbox assembly and the differential of the driven axle is highly constrained. In such a design, the output shaft of the IC engine may need to be extended to allow the hybrid electric drive system to be placed before the gearbox assembly of the IC engine. The hybrid electric drive system can be placed between the clutch/torque converter and the gearbox assembly of the vehicle drivetrain. In this case, the output shaft of the IC engine forms the input for the hybrid electric drive system, and a drive shaft from the hybrid electric drive system forms the input for the gearbox assembly.
[0066] Various objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like features.
[0067] Within the scope of this application, it is expressly envisaged that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.

BRIEF DESCRIPTION OF DRAWINGS
[0068] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure.
[0069] FIG. 1A illustrates an exemplary schematic representation of a hybrid electric drive system for a vehicle, in a first configuration, operating in an electric mode of operation, in accordance with an embodiment of the present disclosure.
[0070] FIG. 1B illustrates an exemplary schematic representation of the hybrid electric drive system, in the first configuration, operating in an engine mode of operation, in accordance with an embodiment of the present disclosure.
[0071] FIG. 1C illustrates an exemplary schematic representation of the hybrid electric drive system, in the first configuration, operating in a combined mode of operation, in accordance with an embodiment of the present disclosure.
[0072] FIG. 1D illustrates an exemplary schematic representation of the hybrid electric drive system, in the first configuration, operating in a regeneration mode of operation, in accordance with an embodiment of the present disclosure.
[0073] FIG. 2A illustrates an exemplary representation of the vehicle from left hand side, in accordance with an embodiment of the present disclosure.
[0074] FIG. 2B illustrates an exemplary representation of the vehicle from right hand side, in accordance with an embodiment of the present disclosure.
[0075] FIG. 2C illustrates an exemplary representation of the vehicle from under side, in accordance with an embodiment of the present disclosure.
[0076] FIG. 3A illustrates an exemplary representation of the hybrid electric drive system from engine side, in accordance with an embodiment of the present disclosure.
[0077] FIG. 3B illustrates an exemplary representation of the hybrid electric drive system from motor side, in accordance with an embodiment of the present disclosure.
[0078] FIG. 3C illustrates another exemplary representation of the hybrid electric drive system from engine side, in accordance with an embodiment of the present disclosure.
[0079] FIGs. 3D and 3E illustrate an exemplary perspective view and exemplary sectional view of the hybrid electric drive system, respectively, in accordance with an embodiment of the present disclosure.
[0080] FIG. 4A illustrates an exemplary representation of an over-running clutch drive unit of the hybrid electric drive system from motor side, in accordance with an embodiment of the present disclosure.
[0081] FIG. 4B illustrates an exemplary representation of an over-running clutch drive unit of the hybrid electric drive system from engine side, in accordance with an embodiment of the present disclosure.
[0082] FIG. 4C illustrates an exemplary representation of an over-running clutch drive unit of the hybrid electric drive system from engine side with a more detailed sectional view, in accordance with an embodiment of the present disclosure.
[0083] FIG. 5A illustrates an exemplary representation depicting working of the hybrid electric drive system when operated in the engine mode, in accordance with an embodiment of the present disclosure.
[0084] FIG. 5B illustrates exemplary representations of a first set of rollers and springs and a second set of rollers and springs of the over-running clutch drive unit when the hybrid electric drive system is operated in the engine mode, in accordance with an embodiment of the present disclosure.
[0085] FIG. 5C illustrates an exemplary representation depicting working of the hybrid electric drive system when operated in the electric mode, in accordance with an embodiment of the present disclosure.
[0086] FIG. 5D illustrates an exemplary representation of the first set of rollers and springs when the hybrid electric drive system is operated in the electric mode, in accordance with an embodiment of the present disclosure.
[0087] FIG. 5E illustrates an exemplary representation depicting working of the hybrid electric drive system when operated in the combined mode, in accordance with an embodiment of the present disclosure.
[0088] FIG. 5F illustrates exemplary representations of the first set of rollers and springs and the second set of rollers and springs when the hybrid electric drive system is operated in the combined mode, in accordance with an embodiment of the present disclosure.
[0089] FIG. 5G illustrates the working of the hybrid electric drive system when operated in a reverse drive mode, in accordance with an embodiment of the present disclosure.
[0090] FIG. 5H illustrates an exemplary representation of a third set of rollers and springs when the hybrid electric drive system is operated in the reverse drive mode, in accordance with an embodiment of the present disclosure.
[0091] FIGs. 6A to 6C illustrate exemplary representations of a hybrid electric drive system, in a second configuration, positioned between an Internal Combustion (IC) engine assembly and a gearbox of a vehicle, in accordance with an embodiment of the present disclosure.
[0092] FIG. 7A illustrates an exemplary representation depicting working of the hybrid electric drive system when operated in the engine mode, in accordance with an embodiment of the present disclosure.
[0093] FIG. 7B illustrates exemplary representations of a set of rollers and springs of the over-running clutch drive unit when the hybrid electric drive system is operated in the engine mode, in accordance with an embodiment of the present disclosure.
[0094] FIG. 7C illustrates an exemplary representation depicting working of the hybrid electric drive system when operated in the electric mode, in accordance with an embodiment of the present disclosure.
[0095] FIG. 7D illustrates an exemplary representation of the set of rollers and springs when the hybrid electric drive system is operated in the electric mode, in accordance with an embodiment of the present disclosure.
[0096] FIG. 7E illustrates an exemplary representation depicting working of the hybrid electric drive system when operated in the combined mode, in accordance with an embodiment of the present disclosure.
[0097] FIG. 7F illustrates exemplary representations of the set of rollers and springs when the hybrid electric drive system is operated in the combined mode, in accordance with an embodiment of the present disclosure.
[0098] FIG. 8 illustrates an exemplary representation of a combined acceleration of the hybrid electric drive system, in accordance with an embodiment of the present disclosure.
[0099] FIG. 9 illustrates an exemplary representation of a hybrid electric drive system, in a third configuration, positioned between a gearbox of an IC engine assembly and a differential of a vehicle, in accordance with an embodiment of the present disclosure.
[00100] FIG. 10A illustrates a graphical representation of resultant torque-speed characteristics delivered by the hybrid electric drive system, in accordance with an embodiment of the present disclosure.
[00101] FIG. 10B illustrates a graphical representation of the resultant torque-speed characteristics of the vehicle under various drive cycles, in accordance with an embodiment of the present disclosure.
[00102] FIG. 10C shows a graphical representation showing the resultant reduction in usage of the IC engine assembly due to operation of the hybrid electric drive system in any of the electric mode and the combined mode, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[00103] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[00104] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[00105] Embodiments of the present invention include various steps, which will be described below. The steps may be performed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special-purpose processor programmed with the instructions to perform the steps. Alternatively, steps may be performed by a combination of hardware, software, and firmware and/or by human operators.
[00106] Various methods described herein may be practiced by combining one or more machine-readable storage media containing the code according to the present invention with appropriate standard computer hardware to execute the code contained therein. An apparatus for practicing various embodiments of the present invention may involve one or more computers (or one or more processors within a single computer) and storage systems containing or having network access to computer program(s) coded in accordance with various methods described herein, and the method steps of the invention could be accomplished by modules, routines, subroutines, or subparts of a computer program product.
[00107] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[00108] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00109] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. These exemplary embodiments are provided only for illustrative purposes and so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. The invention disclosed may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Various modifications will be readily apparent to persons skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention.
[00110] Thus, for example, it will be appreciated by those of ordinary skill in the art that the diagrams, schematics, illustrations, and the like represent conceptual views or processes illustrating systems and methods embodying this invention. The functions of the various elements shown in the figures may be provided through the use of dedicated hardware as well as hardware capable of executing associated software. Similarly, any switches shown in the figures are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the entity implementing this invention. Those of ordinary skill in the art further understand that the exemplary hardware, software, processes, methods, and/or operating systems described herein are for illustrative purposes and, thus, are not intended to be limited to any particular named element.
[00111] Systems depicted in some of the figures may be provided in various configurations. In some embodiments, the systems may be configured as a distributed system where one or more components of the system are distributed across one or more networks in a cloud computing system.
[00112] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[00113] All methods described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[00114] The present invention relates to a hybrid electric drive system for a vehicle that can find application in various rear wheel drive, front wheel drive, four wheel drive and all-wheel drive passenger and commercial vehicles including low-duty, medium-duty and heavy-duty on-highway and off-highway vehicles such as trucks, vans, buses, construction vehicles, defence vehicles, mine trucks, utility trucks, agricultural equipment, tractors as well as passenger cars, vans and Sports Utility Vehicles (SUVs). Although the detailed description of the invention herein is given with respect to a rear wheel-driven light commercial truck, the invention is not restricted to this particular vehicle type, and may also be used in other vehicles and vehicle classes.
[00115] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[00116] The present invention relates to a hybrid electric drive system that optimizes the integration of two independent drives, such as an IC engine and electric powertrains, in a vehicle. More particularly, the present invention pertains to a hybrid electric drive system for a vehicle that includes a combination of powertrains, such as an IC engine and Electric Plug-In Hybrid (PHEV) powertrain, an IC engine and Fuel Cell Electric Hybrids (FC-HEV) powertrain, and other permutations or combinations of powertrains. The hybrid electric drive system serves a dual role by allowing the drive from the combination of powertrains to be transmitted individually to the wheels of the vehicle, while also enabling the seamless addition of power from each powertrain to be transmitted to the wheels. The fuel-agnostic nature of the hybrid electric drive system provides optimal sustainable mobility solutions for all categories of vehicles.
[00117] FIGs. 1A to 1D illustrate exemplary schematic representations of a hybrid electric drive system 106 for a vehicle 100, in a first configuration. The vehicle 100 may include at least a pair of front wheels 102 mounted on a front axle and at least a pair of rear wheels 104 mounted on a rear axle. The vehicle 100 includes the hybrid electric drive system 106 (also interchangeably referred to as the “system” herein) to control the supply of rotary power to any or a combination of the front and rear wheels 102, 104. The system 106 includes an electric motor 108 configured to supply rotary power to the front wheels 102 and/or rear wheels 104 in an electric mode of operation, as clearly shown in FIG. 1A. It also includes an over-running clutch drive unit 110 adapted to regulate the supply of rotary power generated by the electric motor 108 to the front wheels 102 and/or rear wheels 104. The electric motor 108 may be equipped with a motor controller 112, which is configured to regulate the generation of rotary power by the electric motor 108. The electric motor 108 may be adapted to receive electric energy from a battery pack 114 installed in the vehicle 100 to generate rotary power to be delivered to the vehicle wheels 102/104. The vehicle 100 also includes an internal combustion (IC) engine assembly 118, operatively coupled to a gearbox 116 of the vehicle, to supply rotary power to any or a combination of the front and rear wheels 102, 104 in an engine mode of operation, as depicted in FIG. 1B. The vehicle 100 may include a fuelling assembly 120 configured to supply fuel, including at least one of petrol, diesel, gasoline, compressed natural gas (CNG), biofuel, hydrogen (H2), and the like, to the IC engine assembly 118.
[00118] The clutch unit 110 is arranged between the electric motor 108 and the IC engine assembly 118, and is configured to control the supply of rotary power generated by the electric motor 108 and the IC engine assembly 118 to the set of wheels 102 and/or 104 in each of the engine mode, the electric mode, and a combined mode, as shown in FIG. 1C. In the combined mode, the clutch unit 110 supplies combined rotary power generated by both the IC engine assembly 118 and the electric motor 108 to the set of wheels 102/104. In an exemplary embodiment, the technical specification of the electric drive, which includes the electric motor 108, the over-running clutch drive unit, the chip-based microcontroller 122, and the battery 114, can be customized according to the user’s preferences.
[00119] The system 106 includes a smart chip-based microcontroller (also interchangeably referred to as the “controller” herein) 122 configured to control the clutch unit 110 to regulate the supply of rotary power generated by each of the electric motor 108 and the IC engine assembly 118 to the vehicle wheels 102/104. The controller 122 may be operatively connected to the motor controller 112 and an Engine Control Unit (ECU) of the IC engine assembly 118 to regulate the generation of rotary power by the electric motor 108 and the IC engine assembly 118, respectively. In an exemplary embodiment, in the electric mode of operation, the ECU may be configured to stop the IC engine assembly 118 from generating rotary power. Similarly, in the engine mode of operation, the motor controller 112 may be configured to stop the electric motor 108 from generating rotary power. In the combined mode of operation, both the electric motor 108 and the IC engine assembly 118 are configured to generate rotary power, which can be combined/added and seamlessly transmitted to any or a combination of the wheels 102, 104.
[00120] In an exemplary embodiment, the controller 122 may be implemented using various hardware configurations or a combination of software and hardware features. For instance, the controller 122 may incorporate microcontrollers, switches, relays, gates, and specialized hardware features like application-specific integrated circuits (ASICs), electrically erasable programmable read-only memories (EEPROMs), or field-programmable gate arrays (FPGAs). In some cases, memory components like non-volatile random access memory (RAM) or read-only memory (ROM) may also form part of the controller 122. In another embodiment, the controller 122 may be entirely software-based, operating either as part of an operating system or as an application running on one. The controller 122 may be connected to the motor controller 112 and the ECU either wirelessly or in a wired manner.
[00121] In an exemplary embodiment, the system 106 may be employed for converting an existing IC engine-driven vehicle into a hybrid electric vehicle as a retrofit solution. Furthermore, the system 106 may be utilized for building a hybrid electric vehicle at the manufacturing stage using the prevalent IC engine vehicle architecture.
[00122] In an embodiment, the over-running clutch drive unit 110 is configured to facilitate the use of torque generated from both the electric motor 108 and the IC engine assembly 118 either independently or in a combined way. The hybrid electric drive system 106 provides seamless synchronization of rotary power generated by the IC engine assembly 118 and the electric motor 108 in the combined mode of operation, as shown in FIG. 1C.
[00123] FIG. 1D illustrates an exemplary schematic representation of the system 106 operating in a regeneration mode of operation. When the system 106 is operating in the engine mode, rotational motion of the wheels 102/104 may be transmitted to the electric motor 108 through the over-running clutch drive unit 110 to enable the battery pack 114, configured with the electric motor 108, to be charged, depending on the state of charge (SoC) of the battery pack 114. In the regeneration mode, the electric motor 108 acts as a generator and charges the battery pack 114 while the vehicle 100 is being driven by the IC engine assembly 118 only. The vehicle 100 may include at least one brake configured with each wheel of the set of wheels 102/104. Even when the at least one brake is engaged, the electric motor 108 will act as a generator and recharge the battery pack 114.
[00124] FIGs. 2A to 2C illustrate various exemplary representations of the vehicle 100 from different perspective views. The hybrid electric drive system 106 may be incorporated into a rear-wheel-drive configuration of the vehicle 100. The vehicle 100 may include an inverter and Direct Current (DC) converter 202 connected to the ECU, the controller 122 and/or the motor controller 112 to regulate the supply of electric current to various components of the system 106. The vehicle 100 may also include a charging port 204 adapted to receive a receptacle to electrically connect the battery pack 114 to a charging station, enabling the charging of the battery pack 114. The charging port 204 may be located at a convenient and easily accessible point on the vehicle 100. The receptacle may include a three-phase charging adapter to assist in the fast charging of the vehicle’s battery pack 114. The vehicle 100 may include a High Voltage (HV) cable harness 206 and Low Voltage (LV) cable harnesses 212 and 226 for connecting various electrical/electronic components installed in the vehicle 100. The vehicle 100 may include a gear lever 208 adapted to change gear ratios of the gearbox 116 installed in the vehicle 100, a hand brake 210 for engaging the at least one brake configured with each of the wheels 102 and 104, and a mode selector lever 214 configured to allow a user to select between the electric mode of operation, the engine mode of operation, and the combined mode of operation.
[00125] Referring to FIG. 2B, the vehicle 100 may include a brake safety switch 218 configured to detect when the wheel brakes are applied, assisting the system 106 during regeneration mode. The vehicle 100 may include a combined accelerator 220 configured with the electric motor 108 and the IC engine assembly 118 to enable the electric motor 108 to speed up earlier than the IC engine assembly 118, owing to the high initial starting torque of the electric motor 108, in the combined mode of operation. The vehicle 100 may include a mode indicator 222 and an audio-visual indicator 232 adapted to display or notify the current mode of operation of the system 106, as well as a neutral safety switch 224 configured to allow the electric motor 108 or the IC engine assembly 118 to be started only when the vehicle 100 is in a parked state or the gearbox 116 is in a neutral position. The vehicle 100 may be equipped with a motor key switch 228 and an IC engine key switch 230, each of which connects an electrical circuit that provides voltage to the electric motor 108 and the IC engine assembly 118, respectively.
[00126] The components of the hybrid electric drive system 106, such as the electric motor 108, the clutch unit 110, and the controller 122, may be mounted to the chassis of the vehicle 100 using mountings 242 between the gearbox 116 and a rear axle differential 238 of the vehicle, as shown in FIG. 2C. The vehicle 100 may include a propeller shaft (output drive shaft) 236 coupled to an input gear of the differential 238, and an input drive shaft 240 that supplies rotary power to the propeller shaft 236 through the clutch unit 110. The vehicle 100 may be provided with a mode shifter 234 adapted to allow a user to switch between the electric mode of operation, the engine mode of operation, and the combined mode of operation. In an exemplary embodiment, the rotary power generated by the combined or individual powertrains, i.e., the IC engine assembly 118 and the electric motor 108, may be supplied to the rear wheels 104 through the clutch unit 110, which is rotatably coupled to the propeller shaft 236 of the vehicle 100. This drives the differential 238 to control the torque delivered to the rear wheels 104 of the vehicle 100.
[00127] In an exemplary embodiment, FIG. 2A indicates the location of the motor controller 112. To enable the electric mode of operation, the electromagnetic accelerator 220 interacts with the mode selector lever 214 to provide the desired speed control for the rotary power generated by the electric motor 108. The motor controller 112 may enable the electric motor 108 to provide proportionate rotary power according to the torque-speed demand as directed by the combined accelerator 220. Thermistor control may be provided internally through the controller 122 to protect the windings of the electric motor 108 from overheating during a rotor lock situation. The brake safety switch 218 (also interchangeably referred to as the “safety interlock switch” herein) prevents the accidental running of the electric motor 108 while the brakes are engaged. A brake pedal installed within the vehicle 100 may be used to actuate the brake safety switch 218.
[00128] In an exemplary embodiment, when the vehicle 100 is enabled to run in electric mode, the gearbox 116 connected to the IC engine assembly 118 must remain in “neutral mode.” This action is a fool-proof mechanism, achieved by keeping the gear lever 208 in the “neutral” position. A neutral safety switch 224 prevents the activation of electric mode if the gear lever is not in the neutral position. Thus, protection interlocks are achieved. Furthermore, the motor controller 112 provides a regeneration mode to conserve the free-wheeling rotational energy of the driven wheels 102,/104, and also to regenerate when the brakes are engaged, enabling the charging of the battery pack 114 in the regeneration mode, as shown in FIG. 1D. Thus, the system 106 is capable of adding extra miles for the vehicle 100 as a result of the regeneration mode. Additionally, two independent electric key switches 228 and 230 are provided to isolate the electric and engine modes of operation. Vehicle speed and other display parameters may be shown on a custom-built instrument cluster, i.e., the audio-visual indicator 232. The HV cable harness is provided for the power and control circuits, the regeneration circuit of the motor controller 112, the combined accelerator 220, the brake safety switch interlock 218, the neutral gear safety switch 224, the charging circuit of the battery pack 114, and other vehicle operations.
[00129] In a first configuration, the hybrid electric drive system 106 is configured between the gearbox 116 coupled to the IC engine assembly 118 and a driven axle differential 238 of the vehicle 100, as shown in FIGs. 3A to 3C. In a second configuration, the hybrid electric drive system 106 is configured between the IC engine assembly 118 and the gearbox 116 of the vehicle 100, as shown in FIGs. 3D and 3E. In a third configuration, the hybrid electric drive system 106 is configured between a gearbox 116 of the IC engine assembly 118 and a differential 238 mounted on a driven axle of the vehicle 100, as shown in FIG. 9.
[00130] The hybrid electric drive system 106, in the second configuration, is based on the fact that the existing internal combustion engine drivetrain, i.e., the gearbox 116, is kept unaltered up to the IC engine assembly 118. The hybrid electric drive system 106, including the electric motor 108, the over-running clutch drive unit 110, and the smart programmable chip-based microcontroller 122, is added between the gearbox 116 and the driven axle differential 238 in the first configuration, and between the IC engine assembly 118 and the gearbox 116 in the second configuration, as clearly shown in FIG. 6A. The second configuration is preferred in cases where the space available between the gearbox 116 and the differential 238 of the driven axle is highly constrained. In all the first, second and third configurations, the rotary power generated by both the IC engine assembly 118 and the electric motor 108 is transmitted, either individually or in combination, to the output drive shaft 236 rotatably coupled to the driven axle differential 238, which drives the driven wheels 104.
[00131] The IC engine assembly 118 may be configured to drive an input drive shaft 240, which transmits the rotary power generated by the IC engine assembly 118 to the output drive shaft 236 in the engine mode of operation. As shown in FIGs. 3A and 3B, the components of the hybrid electric drive system 106, such as the electric motor 108, the clutch unit 110, and the controller 122, may be mounted to the chassis of the vehicle 100 using mountings 242 between the gearbox 116 and the rear axle differential 238. In an exemplary embodiment, the electric motor 108, the over-running clutch drive unit 110, and the controller 122 may be integrated together to form a single drive module mounted on the chassis between the gearbox 116 and the differential 238 mounted on the driven axle of the vehicle 100.
[00132] In the second configuration, as shown in FIGs. 3D and 3E, the components of the hybrid electric drive system 106, such as the electric motor 108, the clutch unit 110, and the controller 122, may be mounted to the chassis using mountings 242 between the IC engine assembly 118 and the gearbox 116 of the vehicle 100. This configuration provides a substantial advantage for the installation of the hybrid electric drive system 106 in vehicles with severe space constraints between the gearbox 116 and the differential 238. In an exemplary embodiment, the electric motor 108, the over-running clutch drive unit 110, and the controller 122 may be integrated together to form a single drive module mounted on the chassis between the IC engine assembly 118 and the gearbox 116.
[00133] The fuelling system 120 of the vehicle 100 may be equipped with a hydrogen fuel cell stack and a liquid hydrogen tank configured to supply the electrical energy to operate the electric motor 108. The hydrogen fuel cell stack, the liquid hydrogen tank, and the battery pack 114 can be mounted on the chassis of the vehicle 100 at a customizable, appropriate, and convenient location. Additionally or alternatively, the electrical energy to operate the electric motor 108 may be provided by an arrangement of ultra-capacitors, providing one more option for fuelling the electric powertrain. In an exemplary embodiment, the electric motor 108 may be configured to receive electric energy from the battery pack 114 or the hydrogen fuel cell stack of the fuelling assembly 120 mounted on the chassis of the vehicle 100, under the passenger or cargo compartment, thereby preserving the center of gravity of the vehicle 100 as low to the ground as possible for better dynamic behaviour and balance.
[00134] FIG. 4A and 4B illustrate the over-running clutch drive unit 110 of the system 106 from the motor side and engine side, respectively. FIG. 4C illustrates a sectional view of the over-running clutch drive unit 110 from the engine side. The over-running clutch drive unit 110 includes an outer hub assembly 402 configured to receive the rotary power generated by the electric motor 108. The outer hub assembly 402 is rotatably coupled to the propeller shaft (output drive shaft) 236, which is adapted to drive the set of wheels 104. The electric motor 108 may be coupled to the outer hub assembly 402 through a set of gears 420, 422, and 424 or through other drive transmission members/mechanisms, like a chain drive.
[00135] The input drive shaft 240 and the output drive shaft 236 are connected to each other through the over-running clutch drive unit 110, which allows the output drive shaft 236 to receive power from the input drive shaft 240, and hence from the IC engine assembly 118 in the engine mode of operation, or receive power from the electric motor 108 through the outer hub assembly 402 in the electric mode of operation, or receive power from both the IC engine assembly 118 and the electric motor 108 in a combined mode of operation.
[00136] The clutch unit 110 also includes a main coupler hub assembly 404, as clearly shown in FIG. 3C and FIGs. 4A to 4C, mounted on a drive shaft 240 adapted to receive the rotary power generated by the IC engine assembly 118, a first cam plate 406 fixedly coupled with the outer hub assembly 402, and a second cam plate 408 fixedly coupled with the drive shaft 240. The main coupler hub assembly 404 may be mounted on the input drive shaft 240 with the help of a set of bearings 426. The input drive shaft 240 is rotatably coupled to the gearbox 116, such that the input drive shaft 240 is driven by the IC engine assembly 118 through the gearbox 116. A first set of rollers and springs 410, 412 is configured with one or more recesses of the first cam plate 406 to regulate the linkage between the first cam plate 406 and the main coupler hub assembly 404. A second set of rollers and springs 414, 416 is configured with one or more recesses of the second cam plate 408 to regulate the linkage between the second cam plate 408 and the main coupler hub assembly 404. In an exemplary embodiment, the shape of the recesses of the second cam plate 408 may be formed as a mirror image of the recesses of the first cam plate 406.
[00137] The wheels 102, 104 may be mounted on a front axle and a rear axle of the vehicle 100, respectively. The output drive shaft 236 is coupled to the driven axle among the front and rear axles through the differential 238 mounted thereon, to drive the driven wheels 102/104 upon rotation of the main coupler hub assembly 404 in the engine mode of operation, or rotation of the outer hub assembly 402 in the electric mode of operation, or rotation of the output drive shaft 236 based on the combination of the rotary power transmitted by the electric motor 108 and the IC engine assembly 118 in the combined mode of operation.
[00138] The clutch unit 110 includes a shaft coupler 418 adapted to regulate the transmission of rotary power from the drive shaft 240 directly to the propeller shaft 236 in a reverse mode of operation. The shaft coupler 418 comes into use during a reverse mode of operation, in which the IC engine assembly 118 transmits rotary power from the input drive shaft 240 directly to the output drive shaft 236 to propel the vehicle 100 in the reverse direction. The shaft coupler 418 may be in the form of a cylindrical bar.
[00139] The controller 122 of the system 100 is operatively connected to the motor controller 112 and is configured to maintain the rotational speed of the outer hub assembly 402 to be less than the rotational speed of the drive shaft 240 driven by the IC engine assembly 118 during the combined mode of operation. This enables the rotary power generated by both the IC engine assembly 118 and the electric motor 108 to be combined and seamlessly transmitted to the propeller shaft 236 to drive the driven wheels 102/104. The first set of rollers and springs 410, 412, and the second set of rollers and springs 414, 416 of the over-running clutch drive unit 110 are configured to regulate the supply of rotary power generated by the IC engine assembly 118 and the electric motor 108 to the driven wheels 102 and/or 104 in each of the engine mode of operation, the electric mode of operation, and the combined mode of operation.
[00140] FIG. 5A illustrates an exemplary representation depicting the working of the over-running clutch drive unit 110 of the system 106 in the engine mode of operation. In this mode of operation, the IC engine assembly 118 is switched on and the electric motor 108 is shut off. The controller 122 may be operatively connected to the ECU of the IC engine assembly 118 and the motor controller 112 to ensure that the generation of rotary power by the IC engine assembly 118 is enabled and the generation of rotary power by the electric motor 108 is disabled during the engine mode of operation.
[00141] The first set of rollers and springs 410, 412 may be adapted to connect the linkage between the main coupler hub assembly 404 and the first cam plate 406, such that the rotary power transmitted to the main coupler hub assembly 404 by the drive shaft 240 is supplied to the propeller shaft 236 through the first cam plate 406 fixedly coupled to the outer hub assembly 402. The input drive shaft 240 receives rotary power from the IC engine assembly 118. As a result, the second cam plate 408 is driven by the input drive shaft 240 as it is rigidly connected thereto. During this mode, the second set of rollers and springs 414, 416 of the second cam plate 408, as shown in FIG. 5B, get wedged into a position such that the drive of the second cam plate 408 is transmitted by the rollers 414 to the main coupler hub assembly 404. The main coupler hub assembly 404 thus starts rotating at the same speed and direction as the second cam plate 408. The first set of rollers and springs 410, 412 of the first cam plate 406 also get wedged into a position such that the main coupler hub assembly 404 is able to transmit the drive to the first cam plate 406 through the rollers 410. As the first cam plate 406 starts rotating from the drive received from the main coupler hub assembly 404, the first cam plate 406 transmits the rotary drive to the outer hub assembly 402 to which it is rigidly attached. The outer hub assembly 402 in turn transmits the rotary power received from the IC engine assembly 118 to the output drive shaft 236, which is then transmitted to the driven set of wheels 102/104 through the differential 238.
[00142] FIGs. 5C and 5D illustrate the operation of the over-running clutch drive unit 110 in the electric mode, where the electric motor 108 is responsible for driving the wheels 102/104. In this mode, the IC engine assembly 118 is turned off, allowing the electric motor 108 to provide the necessary rotary power to drive the wheels 102/104. The outer hub assembly 402 of the clutch unit 110 receives rotary power from the electric motor 108 via the gear set 420, 422, and 424, and transmits it to the output drive shaft 236, which then rotates the driven wheels 102/104 through the differential 238. In this mode, the first cam plate 406, fixedly attached to the outer hub assembly 402, also receives power from the electric motor 108. However, the first set of rollers and springs 410, 412 are adapted to disconnect the linkage between the first cam plate 406 and the main coupler hub assembly 404. As shown in FIG. 5D, this disconnection allows the first cam plate 406 to rotate independently of the stationary main coupler hub assembly 404. Consequently, the rotary power from the electric motor 108 is transmitted only to the output drive shaft 236 and the driven wheels 102/104, without engaging the IC engine assembly 118.
[00143] FIGs. 5E and 5F depict the operation of the over-running clutch drive unit 110 in the combined mode, when both the IC engine assembly 118 and the electric motor 108 supply power to the wheels 102/104. In this mode, both the IC engine assembly 118 and the electric motor 108 generate rotary power simultaneously. The outer hub assembly 402 receives power from the IC engine assembly 118 via the second cam plate 408 and main coupler hub assembly 404, as in the engine mode. Additionally, the outer hub assembly 402 also receives power from the electric motor 108 through the gear set 420, 422, and 424. To ensure seamless integration of the two powertrains, the controller 122 maintains the rotational speed of the electric motor 108 at the outer hub assembly 402 to be less than the rotational speed of the drive shaft 240 driven by the IC engine assembly 118 at the start of the combined mode. Once the first and second set of rollers and springs get into a position as shown in FIG 5F, the rotational speed of the outer hub assembly 402 and the rotational speed of the drive shaft 240 becomes same and the controller 122 ensures that the rotational speed of the outer hub assembly 402 doesn’t exceed that of the drive shaft 240. This ensures that the rotational power from both the IC engine and electric motor is seamlessly combined and transmitted to the output drive shaft 236, ultimately driving the wheels 102/104 through the differential 238.
[00144] FIGs. 5G and 5H illustrate the operation of the over-running clutch drive unit 110 in reverse mode, where the IC engine assembly 118 provides reverse drive to the wheels 102/104. In this mode, the IC engine assembly 118 is switched on while the electric motor 108 is disabled. The reverse rotation of the input drive shaft 240 causes the second cam plate 408 to rotate in reverse. This reverse movement positions the second set of rollers and springs 414, 416 to prevent the reverse drive from being transmitted to the main coupler hub assembly 404. As a result, the reverse drive is not transmitted to the first cam plate 406 or the output drive shaft 236. In the reverse mode of operation, the second set of rollers and springs 414, 416 are adapted to disconnect the linkage between the second cam plate 408 and the main coupler hub assembly 404, preventing operation in the engine mode. The shaft coupler 418 enables direct transmission of the power from the second cam plate 408 to the propeller shaft 236, in the reverse mode of operation.
[00145] In the reverse mode, the shaft coupler 418, is adapted to transmit reverse drive from the input drive shaft 240 to the output drive shaft 236. The shaft coupler 418 includes a third cam plate 434 fixedly attached to it, along with a third set of rollers and springs 436, 438 that regulate the linkage between the shaft coupler 418 and the hub 432 of the input drive shaft 240. Also, the third set of rollers and springs 436, 438 are adapted, in reverse mode, to connecting the linkage between the third cam plate 434 and the input drive shaft 240 rotating in reverse. This allows the reverse drive from the IC engine assembly 118 to be transmitted to the output drive shaft 236, which rotates in the same direction and speed as the input drive shaft 240. In this arrangement, the shaft coupler 418 connects the input and output drive shafts 240, 236 to transmit reverse drive when the IC engine assembly 118 operates in reverse. In normal engine mode, the shaft coupler 418 freewheels to prevent transmission of rotary power to the third cam plate 434. Thus, the shaft coupler 418 ensures that only the reverse drive is transmitted to the output drive shaft 236 and onto the driven wheels 102/104 via the differential 238 when the IC engine assembly 118 operates in reverse.
[00146] In an exemplary embodiment, the shaft coupler 418 may be adapted to move between a retracted position and an extended position. In the retracted position, the shaft coupler 418 prevents transmission of rotary power from the drive shaft 240 to the propeller shaft 236 when the second set of rollers and springs 414, 416 connects the linkage between the second cam plate 408 and the main coupler hub assembly 404. In the extended position, the shaft coupler 418 is configured to transmit rotary power from the drive shaft 240 directly to the propeller shaft 236 when the second set of rollers and springs 414, 416 disconnect the linkage between the second cam plate 408 and the main coupler hub assembly 404.
[00147] FIG. 6A shows an exemplary schematic representation of a vehicle 100 incorporating the hybrid electric drive system 106 in the second configuration. FIGs. 6B and 6C illustrate sectional views of the over-running clutch drive unit 110. In this second configuration, the over-running clutch drive unit 110 is positioned between the IC engine assembly 118 and the gearbox 116 of the vehicle 100. The clutch unit 110 is designed to manage the supply of rotary power generated by the IC engine assembly 118 and the electric motor 108 to the gearbox 116, which is connected to the wheels 104 in each operational mode: engine mode, electric mode, and combined mode. In this configuration, the clutch unit 110 includes a main cam plate 442 that receives power from the electric motor 108. The main cam plate 442 is rotatably coupled to the output drive (propeller) shaft 260, which drives the gearbox 116 connected to the driven wheels 102/104. The electric motor 108 is connected to the main cam plate 442 through the gear set 420, 422, and 424, or via alternative transmission mechanisms like chain drives. The clutch unit 110 also includes a main coupler hub assembly 444 mounted on an input drive shaft 250, which receives rotary power from the IC engine assembly 118. The input drive shaft 250 is connected to the IC engine assembly 118 and positioned downstream of its clutch or torque converter. The main coupler hub assembly 444 is coupled to the input drive shaft 250 and receives rotary power from it. A set of rollers and springs 446, 448 regulates the linkage between the main cam plate 442 and the main coupler hub assembly 444, allowing for control over the power transmission to the gearbox 116.
[00148] The controller 122 in this configuration is operatively connected to the motor controller 112 and is configured to maintain the rotational speed of the main cam plate 442 to be lower than that of the main coupler hub assembly 444, which is driven by the IC engine assembly 118. This allows the power generated by both the IC engine assembly 118 and the electric motor 108 to be combined and seamlessly transmitted to the output drive shaft 260. The power is then transferred to the gearbox 116, which drives the wheels 102/104. At this stage, the rollers and springs 446, 448 manage the supply of rotary power from both the IC engine assembly 118 and the electric motor 108, ensuring efficient operation in each mode of the hybrid drive system.
[00149] FIGs. 7A and 7B illustrate the operation of the over-running clutch drive unit 110 in the engine mode, when the IC engine assembly 118 provides power to the gearbox 116. The controller 122 is connected to the motor controller 112 and the ECU of the IC engine assembly 118 to ensure that rotary power generation from the electric motor is prevented, while rotary power from the IC engine assembly 118 is enabled during the engine mode. The set of rollers and springs 446 and 448 is adapted to connect the linkage between the main cam plate 442 and the main coupler hub assembly 444, so that the rotary power transmitted to the main coupler hub assembly 444 by the IC engine assembly 118 is supplied to the main cam plate 442. The cam plate then drives the gearbox 116 through the propeller shaft 260. During this mode, the rollers 446 of the main cam plate 442, as shown in FIG. 7B, become wedged into a position where the main coupler hub assembly 444 can transmit the drive to the main cam plate 442 via the rollers 446. As the main cam plate 442 rotates under the drive received from the main coupler hub assembly 444, it transmits power to the output drive shaft 260, which then drives the gearbox 116 and the wheels 102/104.
[00150] FIGs. 7C and 7D illustrate the operation of the over-running clutch drive unit 110 in the electric mode, when the electric motor 108 drives the gearbox 116. In this mode, the IC engine assembly 118 is shut off and the electric motor 108 is powered on. The set of rollers and springs 446 and 448 is adapted to disconnect the linkage between the main cam plate 442 and the main coupler hub assembly 444. As a result, the rotary power transmitted to the main cam plate 442 by the electric motor 108 is supplied to the propeller shaft 260 to drive the gearbox 116, while the main coupler hub assembly 444 remains stationary.
[00151] During the electric mode, the main cam plate 442 receives rotary power generated by the electric motor 108 through the set of gears 420, 422, and 424. It then transmits power to the output drive shaft 260, which drives the gearbox 116 and the wheels 102/104. In this mode, the rollers 446 of the set of rollers and springs 446 and 448 are positioned, as shown in FIG. 7D, to allow the main cam plate 442 to rotate independently of the stationary main coupler hub assembly 444. The rollers 446 are pushed into recesses on the main cam plate 442, permitting rotation without transmitting the drive to the main coupler hub assembly 444. Thus, the drive from the electric motor 108 is directly transmitted only to the output drive shaft 260, and then onto the gearbox 116.
[00152] FIGs. 7E and 7F illustrate the operation of the over-running clutch drive unit 110 in the combined mode, when both the IC engine assembly 118 and the electric motor 108 provide power to the gearbox 116. In this mode, the IC engine assembly 118 and the electric motor 108 are switched on. The set of rollers and springs 446 and 448 connect the linkage between the main cam plate 442 and the main coupler hub assembly 444, so that the rotary power transmitted to the drive shaft 250 by the IC engine assembly 118 is supplied to the main coupler hub assembly 444. At the same time, the rotary power generated by the electric motor 108 is supplied to the main cam plate 442. The controller 122 also ensures that the rotational speed of the main cam plate 442, driven by the electric motor 108, remains lower than the rotational speed of the main coupler hub assembly 444, driven by the IC engine assembly 118 at the starting of this mode. This ensures that the rotary power from both the IC engine assembly 118 and the electric motor 108 is combined and seamlessly transmitted to the propeller shaft 260 to drive the gearbox 116.
[00153] During the combined mode, the main coupler hub assembly 444 receives power from the IC engine assembly 118 in the same way as in the engine mode. Additionally, the main cam plate 442 receives power from the electric motor 108 through the set of gears 420, 422, and 424. In this mode, the controller 122 ensures that the rotary speed received from the electric motor 108 at the main cam plate 442 does not exceed the rotational speed of the main coupler hub assembly 444 and the input drive shaft 250 at the start of this mode. Once the set of rollers and springs 446 and 448 get into a position as shown in FIG 7F, the rotational speed of the main coupler hub assembly 444 and the main cam plate 442 becomes same, and the controller 122 ensures that the rotational speed of the main cam plate 442 doesn’t exceed that of the main coupler hub assembly 444. This ensures that the two powertrains, i.e., the IC engine assembly 118 and the electric motor 108, are seamlessly combined and transmitted to the output drive shaft 260, and then to the gearbox 116.
[00154] FIG. 8 illustrates an exemplary representation of the combined electro-mechanical accelerator 220 of the vehicle 100. The electro-mechanical accelerator 220 may include an accelerator fixture 802, which is used to fixedly mount the accelerator pedal 804 within the vehicle 100. The combined accelerator 220 serves as the accelerator for both the IC engine assembly 118 and the electric motor 108, providing ease of operation for the driver of the vehicle 100, allowing them to maintain their driving habits. The accelerator pedal 804 may be configured to operate both the electric and internal combustion engine accelerators simultaneously. A mechanical cable 808 operates a mechanism that provides the accelerator function for the IC engine assembly 118. The combined accelerator 220 may also include a connecting cable 806, which is operatively connected to the electric motor 108, and a magnetic coupling and sensor 812 that transmit a signal to the motor controller 112 based on the movement of the pedal 804, thereby providing the accelerator function for the electric motor 108. The combined accelerator 220 may include accelerator supports 814 and 818 to ensure proper fitment within the vehicle 100. Additionally, the combined accelerator 220 may feature a mechanical adjuster 810 adapted to adjust the positioning of the mechanical cable 808, which is coupled to the IC engine assembly 118, and a cable stretcher 816 configured to connect to a lever of the accelerator pedal 804. Thus, hybrid accelerator operation can be easily achieved through the common accelerator 220. The common accelerator 220 is configured with an optimized phase lag, allowing the IC engine assembly 118 to lag behind the electric motor 108 when the driver operates the accelerator pedal 804 while driving in combined mode.
[00155] In an exemplary embodiment, the hybrid electric drive system 106 of the present invention synchronizes and transfers the torque generated by the two powertrains to the wheels of the vehicle 100. The hybrid electric drive system 106 serves the dual role of allowing the drive from each powertrain to be transmitted individually to the wheels of the vehicle 102/104 as demanded by the user, and of combining the drives from each powertrain and seamlessly transmitting them to the wheels of the vehicle 102/104 as required. The hybrid electric drive system 106 enables the true addition of the capabilities of the two distinct powertrains, preventing the splitting of the torque generated by either powertrain and instead adding the torque to meet the vehicle’s load demand by synchronizing the drives. This ensures the best utilization of the torque-speed characteristics of both powertrains. The hybrid electric drive system 106 makes unique use of the over-running clutch drive unit 110 with the programmable chip-based microcontroller 122 to provide the necessary synchronization between the drives from the two powertrains. When the user operates the hybrid electric drive system 106 in the combined mode, the over-running clutch drive unit 110 is controlled by the programmable microcontroller 122 to take advantage of the torque-speed characteristics of the individual powertrains. The combined accelerator conveys the user’s demand to the hybrid electric drive system 106, and based on the total torque demand of the vehicle 100, the combination of the two powertrains is managed to deliver the required torque with the best possible efficiency.
[00156] The combined accelerator 220 is equipped with an optimized phase lag that allows the IC engine assembly 118 to lag behind the electric motor 108, taking advantage of the high initial starting torque of the electric motor 108 during the combined mode of operation. In this mode, the combined accelerator 220 is configured to allow the electric motor 108 to speed up earlier while the IC engine assembly 118 is still at idle speed, based on the programmable phase lag. The high starting torque of the electric motor 108 propels the vehicle 100 by providing the necessary torque up to a first programmable threshold speed of the vehicle. As the speed of the vehicle increases above this first programmable threshold speed, the IC engine assembly 118 begins providing the necessary torque to continue propelling the vehicle 100. At this stage, the chip-based microcontroller 122 commands the motor controller 112 to set the output rotational speed at the outer hub assembly 402 to be lower than the rotational speed of the input drive shaft 240, ensuring that there is no slip between the first cam plate 406 and the main coupler hub assembly 404. Once the first cam plate 406 locks with the main coupler hub assembly 404, both rotate at the same speed. This results in a seamless addition of the two drives, with the electric motor 108 assisting the IC engine assembly 118 to propel the vehicle 100, while keeping the IC engine assembly 118 operating in its highest efficiency zones. At a second programmable threshold speed, the IC engine assembly 118 operates more efficiently than the electric motor 108. At this point, the controller 122 shuts off the electric motor 108, and only the IC engine assembly 118 propels the vehicle 100. If the speed of the vehicle 100 drops below the second programmable threshold but remains above the first, the controller 122 turns the electric motor 108 back on to assist the IC engine assembly 118 in propelling the vehicle 100. If the vehicle speed falls below the first programmable threshold, the controller 122, with the help of the combined accelerator 220, enables the electric motor 108 to provide the necessary drive to propel the vehicle 100, while the IC engine assembly 118 operates at idle speed. Thus, during the combined mode of operation, the chip-based microcontroller 122, along with the combined accelerator 220, enables propulsion of the vehicle 100 while ensuring the use of the highest efficiency zones of either powertrain.
[00157] FIG. 9 illustrates an exemplary representation of a hybrid electric drive system 106, in a third configuration, positioned between the gearbox 116 of the IC engine assembly and the differential 238 of the vehicle. The system 106 of the third configuration may have similar structure as the system 106 of the first configuration, except the system 106, in the third configuration, includes an over-running clutch drive unit 110 that is arranged between the gearbox 116 of the IC engine assembly (118) and the differential (238) mounted on a driven axle driving the set of wheels 102/104. The over-running clutch drive unit 110 includes a single main cam plate 442 configured to receive the rotary power generated by the electric motor 108. The main cam plate 442, as shown in FIG. 7B, is rotatably coupled to the propeller shaft 236 adapted to drive any or a combination of the driven wheels 102, 104. The over-running clutch drive unit 110 also includes a main coupler hub assembly 444 mounted on the drive shaft 240 adapted to receive the rotary power generated by the IC engine assembly 118, a set of rollers and springs 446, 448 configured with one or more recesses of the main cam plate 442 to regulate linkage between the main cam plate 442 and the main coupler hub assembly 444, and a shaft coupler 418 adapted to regulate transmission of the rotary power from the drive shaft 240 directly to the propeller shaft 236, in a reverse mode of operation.
[00158] In the third configuration of the system 106, the controller 122 is operatively connected to the motor controller 112 to regulate generation of rotary power by the electric motor 108. The controller 122 is configured to maintain rotational speed of the main cam plate 442 to be less than the rotational speed of the drive shaft 240 driven by the IC engine assembly 118, during the combined mode of operation, to enable the rotary power generated by both the IC engine assembly 118 and the electric motor 108 to be combined and seamlessly transmitted to the propeller shaft 236 to drive the set of wheels 102/104.
[00159] In the engine mode of operation, the motor controller 112 may be configured to disables generation of the rotary power by the electric motor 108. At this stage, the set of rollers and springs 446, 448 is adapted to connect the linkage between the main cam plate 442 and the main coupler hub assembly 444, such that the rotary power transmitted to the main coupler hub assembly 444 by the drive shaft 240 is supplied to the main cam plate 442 that drives the propeller shaft 236.
[00160] In the electric mode of operation, the motor controller 112 may be configured to enable generation of the rotary power by the electric motor 108. The set of rollers and springs 446, 448 is configured to disconnect the linkage between the main cam plate 442 and the main coupler hub assembly 444, such that the rotary power transmitted to the main cam plate 442 by the electric motor 108 is supplied to the propeller shaft 236, and the main coupler hub assembly 444 remains stationary.
[00161] In the combined mode of operation, the ECU may be configured to enable generation of the rotary power by the IC engine assembly 118, and the motor controller 112 may be configured to enable generation of the rotary power by the electric motor 108. Thereafter, the set of rollers and springs 446, 448 is adapted to connect the linkage between the main cam plate 442 and the main coupler hub assembly 444, such that the rotary power transmitted to the drive shaft 240 by the IC engine assembly 118 is supplied to the main coupler hub assembly 444, and the rotary power generated by the electric motor 108 is supplied to the main cam plate 442, and the controller 122 maintains the rotational speed of the main cam plate 442 driven by the electric motor 108 to be less than the rotational speed of the main coupler hub assembly 444 driven by the IC engine assembly 118 to enable the rotary power generated by both the IC engine assembly 118 and the electric motor 108 to be combined and seamlessly transmitted to the propeller shaft 236 to drive the set of wheels 102/104.
[00162] In the reverse mode of operation, the ECU enables generation of the rotary power by the IC engine assembly 118 to rotate the drive shaft 240 in a reverse direction, and the motor controller 112 disables generation of the rotary power by the electric motor 108. The set of rollers and springs 446, 448 is adapted to disconnect the linkage between the main coupler hub assembly 444 and the main cam plate 442, and the shaft coupler 418 is configured to directly transmit the rotary power from the drive shaft 240 rotating in the reverse direction to the propeller shaft 236.
[00163] The shaft coupler 418 of the system, in the third configuration, may include a third cam plate 434 fixedly coupled with the shaft coupler 418, and a third set of rollers and springs 436, 438 configured with one or more recesses of the third cam plate 434 to regulate linkage between the shaft coupler 418 and a hub 432 of the drive shaft 240. The third set of rollers and springs 436, 438 is configured to connect the linkage between the third cam plate 434 of the shaft coupler 418 and the hub 432 of the drive shaft 240 rotating in the reverse direction, in the reverse mode of operation, such that the rotary power transmitted to the drive shaft 240 by the IC engine assembly 118 is supplied to the propeller shaft 236 that rotates with the same speed and direction as the drive shaft 240.
[00164] FIG. 10A illustrates a graphical representation of the resultant torque-speed characteristics delivered by the hybrid electric drive system 106. FIG. 10A represents a graph where the x-axis is speed in revolutions per minute (rev/min) and the y-axis is torque in N-m (Newton-meters). The graph shows the torque-speed characteristics of the electric motor 108 in the electric mode of operation, the IC engine assembly 118 in the engine mode of operation, and the resultant torque-speed characteristics of the system 106 in the combined mode. It can be observed that the resultant torque of the hybrid electric drive system 106 exceeds the maximum torque possible from the IC engine assembly 118. During experimentation, it was also found that the high resultant torque delivered by the system 100 is available even at very low initial starting speeds, thereby significantly reducing the load on the IC engine assembly 118.
[00165] FIG. 10B illustrates a graphical representation of the vehicle 100’s resultant torque-speed characteristics under various drive cycles, such as start-up and heavy acceleration (power zone), partial load condition (eco zone), and steady-state cruise condition (cruise zone). FIG. 10B represents a graph where the x-axis is speed in revolutions per minute (rev/min) and the y-axis is torque in N-m (Newton-meters). The graph includes representations of different gears, such as 1st gear, 2nd gear, 3rd gear, etc., of the gearbox 116 of the IC engine assembly 118, along with various zones such as the cruise zone, eco zone, and power zone. It can be seen that the resultant torque-speed characteristics of the hybrid electric drive system 106 allow the vehicle 100 to operate in 3rd or higher gears in the power zone, unlike the engine mode, where 1st or 2nd gear is needed in the power zone. This means that the IC engine assembly 118 is loaded less to provide the necessary drive when the vehicle 100 is driven in the combined mode, resulting in fuel savings and a reduction in harmful emissions from the IC engine.
[00166] It can also be seen that the majority of the high torque delivered by the hybrid electric drive system 106 is available even from low initial speeds, helping to keep the rotational speeds of the IC engine assembly 118 much lower than desired, as the IC engine assembly 118 doesn’t need to provide the full torque to meet the vehicle’s load requirements. By synchronizing both powertrains, the hybrid electric drive system 106 reduces the load on the IC engine assembly 118, thereby decreasing fossil fuel consumption and reducing carbon and other harmful emissions by nearly 50%. Further reductions in harmful emissions can be achieved by improving the efficiency of the electric motor 108 and the battery pack 114.
[00167] FIG. 10C illustrates a graph indicating a model-derived prediction of the resultant reduction in the usage of the IC engine assembly, leading to a reduction in fossil fuel usage and tailpipe emissions by utilizing the hybrid electric drive system 106. FIG. 10C represents a graph showing the savings in the IC engine assembly’s power (in percentage) due to the hybrid electric drive system 106. When the vehicle 100 is operated in the 1st gear requirement zone, the maximum power saving for the IC engine assembly 118 can be 85.84%, and the minimum power saving can be 84.29%. In the 2nd gear requirement zone, the maximum power saving can be 80.31%, and the minimum power saving can be 76.31%. In the 3rd gear requirement zone, the maximum power saving can be 47.98%, and the minimum power saving can be 34.68%. The maximum power saving in the power zone can be 83.08%, and the minimum power saving in the power zone can be 80.30%. The maximum power saving in the eco zone can be 64.15%, and the minimum power saving in the eco zone can be 55.49%. The maximum power saving in the cruise zone can be 47.98%, and the minimum power saving in the cruise zone can be 32.86%. Finally, the predicted overall maximum power saving for the IC engine assembly 118 can be 65.07%, and the predicted overall minimum power saving can be 56.22%.
[00168] Although this present invention has been described herein with respect to a number of specific illustrative embodiments, the foregoing description is intended to illustrate, rather than to limit the invention. Those skilled in the art will realize that many modifications of the illustrative embodiment could be made which would be operable. All such modifications, which are within the scope of the claims, are intended to be within the scope and of the present invention.

ADVANTAGES OF THE PRESENT DISCLOSURE
[00169] The present disclosure provides an efficient mechanism for building low-emission, fuel-saving hybrid electric drive systems that can operate both independently and in combined mode. Such a system would significantly improve fuel economy and lead to a substantial reduction in CO2 emissions per kilometre.
[00170] The present disclosure provides a hybrid electric drive system that increases the life expectancy of the vehicle.
[00171] The present disclosure provides a hybrid electric drive system that offers a cost-effective solution to reduce emissions from vehicles.
[00172] The present disclosure provides a hybrid electric drive system that helps conserve fossil fuel usage, thereby reducing the import bills for such fuels at the national level.
[00173] The present disclosure provides a hybrid electric drive system that helps repurpose/upcycle existing internal combustion (IC) engine vehicle architectures into cost-effective, low-emission, consumer-friendly mobility solutions, while also reducing design and manufacturing costs for manufacturers.
[00174] Using this invention, OEMs can either manufacture new PHEV or FC-HEV variants of their existing ICE vehicles, or promote retrofit conversion solutions through their authorized service/dealer networks. Both options offer significant additional revenue opportunities, while leading to substantially higher green miles and helping to meet stricter Corporate Average Fuel Economy (CAFÉ) regulatory standards. On a national level, the resulting savings on imported fossil fuels, along with the consequential benefits to the national economy, represent a huge advantage.
[00175] The present invention can be extremely beneficial for consumers, as it offers the opportunity to recover substantial initial vehicle costs due to reduced operating costs over the vehicle’s lifespan. Since employment will be retained and can grow further across the ICE/EV/FCEV supply chains, and multiple fuels can be used, this invention is highly inclusive for the economy.
[00176] Thus, the present invention provides a win-win solution for all stakeholders, such as the government, OEMs, consumers, the economy, and the environment, with shared interests in its success.
, Claims:1. A hybrid electric drive system (106) for a vehicle (100), the hybrid electric drive system (106) comprising:
an Internal Combustion (IC) engine assembly (118) configured to drive a set of wheels (102/104) of the vehicle in an engine mode of operation;
an electric motor (108) configured to drive the set of wheels (102/104) in an electric mode of operation;
an over-running clutch drive unit (110) arranged between a gearbox (116) of the IC engine assembly (118) and a differential (238) mounted on a driven axle driving the set of wheels (102/104), and configured to control supply of the rotary power generated by the IC engine assembly (118) and the electric motor (108) to the set of wheels (102/104) in each of the engine mode of operation, the electric mode of operation, and a combined mode of operation, wherein the over-running clutch drive unit (110), in the combined mode of operation, supplies a combined rotary power generated by both the IC engine assembly (118) and the electric motor (108) to the set of wheels (102/104), and wherein the over-running clutch drive unit (110) comprises:
an outer hub assembly (402) configured to receive the rotary power generated by the electric motor (108), wherein the outer hub assembly (402) is rotatably coupled to a propeller shaft (236) adapted to drive the set of wheels (102/104);
a main coupler hub assembly (404) mounted on a drive shaft (240) adapted to receive the rotary power generated by the IC engine assembly (118);
a first cam plate (406) fixedly coupled with the outer hub assembly (402);
a second cam plate (408) fixedly coupled with the drive shaft (240);
a first set of rollers and springs (410, 412) configured with one or more recesses of the first cam plate (406) to regulate linkage between the first cam plate (406) and the main coupler hub assembly (404);
a second set of rollers and springs (414, 416) configured with one or more recesses of the second cam plate (408) to regulate the linkage between the second cam plate (408) and the main coupler hub assembly (404); and
a shaft coupler (418) adapted to regulate transmission of the rotary power from the drive shaft (240) directly to the propeller shaft (236), in a reverse mode of operation; and
a controller (122) operatively connected to a motor controller (112) configured with the electric motor (108) to regulate generation of rotary power by the electric motor (108), and configured to maintain rotational speed of the outer hub assembly (402) to be less than the rotational speed of the drive shaft (240) driven by the IC engine assembly (118), during the combined mode of operation, to enable the rotary power generated by both the IC engine assembly (118) and the electric motor (108) to be combined and seamlessly transmitted to the propeller shaft (236) to drive the set of wheels (102/104).
2. The hybrid electric drive system (106) as claimed in claim 1, wherein the set of wheels (102/104) are mounted on an axle of the vehicle, and wherein the propeller shaft (236) is coupled to the axle through a differential (238) to drive the set of wheels (102/104) upon any of:
rotation of the main coupler hub assembly (404) in the engine mode of operation,
rotation of the outer hub assembly (402) in the electric mode of operation, or
rotation of the propeller shaft (236) based on combination of the rotary power transmitted by the IC engine assembly (118) and the electric motor (108) in the combined mode of operation.
3. The hybrid electric drive system (106) as claimed in claim 1, wherein the electric motor (108) is coupled to the outer hub assembly (402) through a transmission member comprising at least one of a set of gears (420, 422 and 424) and a chain drive.
4. The hybrid electric drive system (106) as claimed in claim 2, wherein the electric motor (108), the over-running clutch drive unit (110) and the controller (122) are integrated together to form a single drive module mounted on a chassis of the vehicle (100) between a gearbox (116) of the IC engine assembly (118) and the differential (238) mounted on the axle coupled to the propeller shaft (236).
5. The hybrid electric drive system (106) as claimed in claim 1, wherein the first set of rollers and springs (410, 412) and the second set of rollers and springs (414, 416) of the over-running clutch drive unit (110) are adapted to regulate supply of the rotary power generated by the IC engine assembly (118) and the electric motor (108) to the set of wheels (102/104) in each of the engine mode of operation, the electric mode of operation, and the combined mode of operation.
6. The hybrid electric drive system (106) as claimed in claim 1, wherein the second set of rollers and springs (414, 416), in the engine mode of operation, is configured to connect the linkage between the second cam plate (408) and the main coupler hub assembly (404), such that the rotary power transmitted to the drive shaft (240) by the IC engine assembly (118) is supplied to the main coupler hub assembly (404) that rotates with the same speed and direction as the second cam plate (408).
7. The hybrid electric drive system (106) as claimed in claim 6, wherein:
the motor controller (112) is configured to disable generation of the rotary power by the electric motor (108), in the engine mode of operation, and
the first set of rollers and springs (410, 412) is adapted to connect the linkage between the main coupler hub assembly (404) and the first cam plate (406), such that the rotary power transmitted to the main coupler hub assembly (404) by the drive shaft (240) is supplied to the propeller shaft (236) through the first cam plate (406) fixedly coupled to the outer hub assembly (402).
8. The hybrid electric drive system (106) as claimed in claim 1, wherein the controller (122) is operatively connected to an Engine Control Unit (ECU) of the IC engine assembly (118) configured to control generation of the rotary power from the IC engine assembly (118).
9. The hybrid electric drive system (106) as claimed in claim 8, wherein:
the motor controller (112) is configured to enable generation of the rotary power by the electric motor (108), in the electric mode of operation, and
the first set of rollers and springs (410, 412) is adapted to disconnect the linkage between the first cam plate (406) and the main coupler hub assembly (404), such that the rotary power transmitted to the outer hub assembly (402) by the electric motor (108) is supplied to the propeller shaft (236) through the outer hub assembly (402), and the main coupler hub assembly (404) remains stationary.
10. The hybrid electric drive system (106) as claimed in claim 8, wherein in the combined mode of operation:
the ECU is configured to enable generation of the rotary power by the IC engine assembly (118),
the motor controller (112) is configured to enable generation of the rotary power by the electric motor (108),
the second set of rollers and springs (414, 416) is adapted to connect the linkage between the second cam plate (408) and the main coupler hub assembly (404), such that the rotary power transmitted to the drive shaft (240) by the IC engine assembly (118) is supplied to the main coupler hub assembly (404) that rotates with the same speed and direction as the second cam plate (408), and
the first set of rollers and springs (410, 412) is adapted to connect the linkage between the main coupler hub assembly (404) and the first cam plate (406), such that the rotary power transmitted to the main coupler hub assembly (404) by the IC engine assembly (118) driving the drive shaft (240) is supplied to the first cam plate (406) fixedly coupled to the outer hub assembly (402), wherein
the rotary power transmitted from the IC engine assembly (118) to the outer hub assembly (402) is combined with the rotary power transmitted from the electric motor (108) directly to the outer hub assembly (402), and the combined rotary power is seamlessly transmitted to the propeller shaft (236) to drive the set of wheels (102/104).
11. The hybrid electric drive system (106) as claimed in claim 1, wherein the vehicle comprises a combined accelerator (220) configured with the electric motor (108) and the IC engine assembly (118) to enable the electric motor (108) to speed up earlier than the IC engine assembly (118) owing to high initial starting torque of the electric motor (108), in the combined mode of operation.
12. The hybrid electric drive system (106) as claimed in claim 8, wherein in the reverse mode of operation:
the ECU enables generation of the rotary power by the IC engine assembly (118) to rotate the drive shaft (240) in a reverse direction,
the motor controller (112) disables generation of the rotary power by the electric motor (108),
the second set of rollers and springs (414, 416) is adapted to disconnect the linkage between the second cam plate (408) coupled to the drive shaft (240) and the main coupler hub assembly (404), and
the shaft coupler (418) is adapted to directly transmit the rotary power from the second cam plate (408) rotating in the reverse direction to the propeller shaft (236).
13. The hybrid electric drive system (106) as claimed in claim 1, wherein the shaft coupler (418) comprises:
a third cam plate (434) fixedly coupled with the shaft coupler (418); and
a third set of rollers and springs (436, 438) configured with one or more recesses of the third cam plate (434) to regulate linkage between the shaft coupler (418) and a hub (432) of the drive shaft (240),
the third set of rollers and springs (436, 438) is configured to connect the linkage between the third cam plate (434) of the shaft coupler (418) and the hub (432) of the drive shaft (240) rotating in the reverse direction, in the reverse mode of operation, such that the rotary power transmitted to the drive shaft (240) by the IC engine assembly (118) is supplied to the propeller shaft (236) that rotates with the same speed and direction as the drive shaft (240).
14. The hybrid electric drive system (106) as claimed in claim 11, wherein the controller (122) is operatively connected to the combined accelerator (220) to enable propulsion of the vehicle in the highest efficiency zone of either of the IC engine assembly (118) and the electric motor (108) in the combined mode of operation.
15. The hybrid electric drive system (106) as claimed in claim 1, wherein in the engine mode of operation, the rotary power transmitted to the set of wheels (102/104) is supplied to the electric motor (108) through the over-running clutch drive unit (110) to enable a battery pack (114) configured with electric motor (108) to be charged.
16. The hybrid electric drive system (106) as claimed in claim 4, wherein the vehicle (100) comprises a fuelling assembly having a hydrogen fuel cells stack and a liquid hydrogen tank configured to supply electrical energy to operate the electric motor (108), wherein the hydrogen fuel cells stack, the liquid hydrogen tank and the battery pack (114) is mounted on the chassis of the vehicle (100).
17. The hybrid electric drive system (106) as claimed in claim 1, wherein the electric motor (108) is configured to receive electrical energy from a stack of ultra-capacitors.
18. A vehicle (100) comprising the hybrid electric drive system (106) as claimed in claim 1.
19. A hybrid electric drive system (106) for a vehicle, the hybrid electric drive system (106) comprising:
an Internal Combustion (IC) engine assembly (118) configured to drive a set of wheels (102/104) of the vehicle in an engine mode of operation;
an electric motor (108) configured to drive the set of wheels (102/104) in an electric mode of operation;
an over-running clutch drive unit (110) arranged between the IC engine assembly (118) and a gearbox (116) of vehicle (100), and configured to control supply of the rotary power generated by the IC engine assembly (118) and the electric motor (108) to the gearbox (116) operatively coupled to the set of wheels (102/104) in each of the engine mode of operation, the electric mode of operation, and a combined mode of operation, wherein the over-running clutch drive unit (110), in the combined mode of operation, supplies a combined rotary power generated by both the IC engine assembly (118) and the electric motor (108) to the gearbox (116) to drive the set of wheels (102/104), and wherein the over-running clutch drive unit (110) comprises:
a main cam plate (442) configured to receive the rotary power generated by the electric motor (108), wherein the main cam plate (442) is rotatably coupled to a propeller shaft (260) configured to drive the gearbox (116);
a main coupler hub assembly (444) mounted on a drive shaft (250) adapted to receive the rotary power generated by the IC engine assembly (118);
a set of rollers and springs (446, 448) configured with one or more recesses of the main cam plate (442) to regulate linkage between the main cam plate (442) and the main coupler hub assembly (444); and
a controller (122) operatively connected to a motor controller (112) configured with the electric motor (108) to regulate generation of rotary power by the electric motor (108), and configured to maintain rotational speed of the main cam plate (442) to be less than the rotational speed of the main coupler hub assembly (444) driven by the IC engine assembly (118) through the drive shaft (250), during the combined mode of operation, to enable the rotary power generated by both the IC engine assembly (118) and the electric motor (108) to be combined and seamlessly transmitted to the propeller shaft (260) to drive the gearbox (116).
20. The hybrid electric drive system (106) as claimed in claim 19, wherein the electric motor (108), the over-running clutch drive unit (110) and the controller (122) are integrated together to form a single drive module mounted on a chassis of the vehicle (100) between the IC engine assembly (118) and the gearbox (116).
21. The hybrid electric drive system (106) as claimed in claim 19, wherein the set of rollers and springs (446, 448) of the over-running clutch drive unit (110) is adapted to regulate supply of the rotary power generated by the IC engine assembly (118) and the electric motor (108) to the gearbox (116) driving the set of wheels (102/104) in each of the engine mode of operation, the electric mode of operation, and the combined mode of operation.
22. The hybrid electric drive system (106) as claimed in claim 19, wherein:
the motor controller (112) is configured to disable generation of the rotary power by the electric motor (108), in the engine mode of operation, and
the set of rollers and springs (446, 448) is adapted to connect the linkage between the main cam plate (442) and the main coupler hub assembly (444), such that the rotary power transmitted to the main coupler hub assembly (444) by the IC engine assembly (118) is supplied to the main cam plate (442) that drives the gearbox (116) through the propeller shaft (260).
23. The hybrid electric drive system (106) as claimed in claim 19, wherein the controller (122) is operatively connected to an Engine Control Unit (ECU) of the IC engine assembly (118) configured to control generation of the rotary power from the IC engine assembly (118).
24. The hybrid electric drive system (106) as claimed in claim 23, wherein:
the motor controller (112) is configured to enable generation of the rotary power by the electric motor (108), in the electric mode of operation, and
the set of rollers and springs (446, 448) is adapted to disconnect the linkage between the main cam plate (442) and the main coupler hub assembly (444), such that the rotary power transmitted to the main cam plate (442) by the electric motor (108) is supplied to the propeller shaft (260) to drive the gearbox (116), and the main coupler hub assembly (444) remains stationary.
25. The hybrid electric drive system (106) as claimed in claim 23, wherein in the combined mode of operation:
the ECU is configured to enable generation of the rotary power by the IC engine assembly (118),
the motor controller (112) is configured to enable generation of the rotary power by the electric motor (108),
the set of rollers and springs (446, 448) is adapted to connect the linkage between the main cam plate (442) and the main coupler hub assembly (444), such that the rotary power transmitted to the drive shaft (250) by the IC engine assembly (118) is supplied to the main coupler hub assembly (444), and the rotary power generated by the electric motor (108) is supplied to the main cam plate (442), and
the controller (122) maintains the rotational speed of the main cam plate (442) driven by the electric motor (108) to be less than the rotational speed of the main coupler hub assembly (444) driven by the IC engine assembly (118) to enable the rotary power generated by both the IC engine assembly (118) and the electric motor (108) to be combined and seamlessly transmitted to the propeller shaft (260) to drive the gearbox (116).
26. The hybrid electric drive system (106) as claimed in claim 19, wherein the vehicle (100) comprises a combined accelerator (220) configured with the electric motor (108) and the IC engine assembly (118) to enable the electric motor (108) to speed up earlier than the IC engine assembly (118) owing to high initial starting torque of the electric motor (108), in the combined mode of operation.
27. The hybrid electric drive system (106) as claimed in claim 26, wherein the controller (122) is operatively connected to the combined accelerator (220) to enable propulsion of the vehicle in the highest efficiency zone of either of the IC engine assembly (118) and the electric motor (108) in the combined mode of operation.
28. The hybrid electric drive system (106) as claimed in claim 19, wherein in the engine mode of operation, the rotary power transmitted to the set of wheels (102/104) is supplied to the electric motor (108) through the over-running clutch drive unit (110) to enable a battery pack (114) configured with electric motor (108) to be charged.
29. The hybrid electric drive system (106) as claimed in claim 20, wherein the vehicle (100) comprises a fuelling assembly having a hydrogen fuel cells stack and a liquid hydrogen tank configured to supply electrical energy to operate the electric motor (108), wherein the hydrogen fuel cells stack, the liquid hydrogen tank and the battery pack (114) is mounted on the chassis of the vehicle (100).
30. The hybrid electric drive system (106) as claimed in claim 19, wherein the electric motor (108) is configured to receive electrical energy from a stack of ultra-capacitors.
31. A vehicle (100) comprising the hybrid electric drive system (106) as claimed in claim 19.
32. A hybrid electric drive system (106) for a vehicle (100), the hybrid electric drive system (106) comprising:
an Internal Combustion (IC) engine assembly (118) configured to drive a set of wheels (102/104) of the vehicle in an engine mode of operation;
an electric motor (108) configured to drive the set of wheels (102/104) in an electric mode of operation;
an over-running clutch drive unit (110) arranged between a gearbox (116) of the IC engine assembly (118) and a differential (238) mounted on a driven axle driving the set of wheels (102/104), and configured to control supply of the rotary power generated by the IC engine assembly (118) and the electric motor (108) to the set of wheels (102/104) in each of the engine mode of operation, the electric mode of operation, and a combined mode of operation, wherein the over-running clutch drive unit (110), in the combined mode of operation, supplies a combined rotary power generated by both the IC engine assembly (118) and the electric motor (108) to the set of wheels (102/104), and wherein the over-running clutch drive unit (110) comprises:
a main cam plate (442) configured to receive the rotary power generated by the electric motor (108), wherein the main cam plate (442) is rotatably coupled to a propeller shaft (236) adapted to drive the set of wheels (102/104);
a main coupler hub assembly (444) mounted on a drive shaft (240) adapted to receive the rotary power generated by the IC engine assembly (118);
a set of rollers and springs (446, 448) configured with one or more recesses of the main cam plate (442) to regulate linkage between the main cam plate (442) and the main coupler hub assembly (444); and
a shaft coupler (418) adapted to regulate transmission of the rotary power from the drive shaft (240) directly to the propeller shaft (236), in a reverse mode of operation; and
a controller (122) operatively connected to a motor controller (112) configured with the electric motor (108) to regulate generation of rotary power by the electric motor (108), and configured to maintain rotational speed of the main cam plate (442) to be less than the rotational speed of the drive shaft (240) driven by the IC engine assembly (118), during the combined mode of operation, to enable the rotary power generated by both the IC engine assembly (118) and the electric motor (108) to be combined and seamlessly transmitted to the propeller shaft (236) to drive the set of wheels (102/104).
33. The hybrid electric drive system (106) as claimed in claim 32, wherein the propeller shaft (236) is coupled to the driven axle through the differential (238) to drive the set of wheels (102/104) upon any of:
rotation of the main coupler hub assembly (444) in the engine mode of operation,
rotation of the main cam plate (442) in the electric mode of operation, or
rotation of the propeller shaft (236) based on combination of the rotary power transmitted by the IC engine assembly (118) and the electric motor (108) in the combined mode of operation.
34. The hybrid electric drive system (106) as claimed in claim 32, wherein the electric motor (108) is coupled to the main cam plate (442) through a transmission member comprising at least one of a set of gears (420, 422 and 424) and a chain drive.
35. The hybrid electric drive system (106) as claimed in claim 33, wherein the electric motor (108), the over-running clutch drive unit (110) and the controller (122) are integrated together to form a single drive module mounted on a chassis of the vehicle (100) between a gearbox (116) of the IC engine assembly (118) and the differential (238) mounted on the driven axle coupled to the propeller shaft (236).
36. The hybrid electric drive system (106) as claimed in claim 32, wherein the set of rollers and springs (446, 448) of the over-running clutch drive unit (110) is adapted to regulate supply of the rotary power generated by the IC engine assembly (118) and the electric motor (108) to the set of wheels (102/104) in each of the engine mode of operation, the electric mode of operation, and the combined mode of operation.
37. The hybrid electric drive system (106) as claimed in claim 32, wherein in the engine mode of operation:
the motor controller (112) is configured to disable generation of the rotary power by the electric motor (108), and
the set of rollers and springs (446, 448) is adapted to connect the linkage between the main cam plate (442) and the main coupler hub assembly (444), such that the rotary power transmitted to the main coupler hub assembly (444) by the drive shaft (240) is supplied to the main cam plate (442) that drives the propeller shaft (236).
38. The hybrid electric drive system (106) as claimed in claim 32, wherein the controller (122) is operatively connected to an Engine Control Unit (ECU) of the IC engine assembly (118) configured to control generation of the rotary power from the IC engine assembly (118).
39. The hybrid electric drive system (106) as claimed in claim 38, wherein in the electric mode of operation:
the motor controller (112) is configured to enable generation of the rotary power by the electric motor (108), and
the set of rollers and springs (446, 448) is adapted to disconnect the linkage between the main cam plate (442) and the main coupler hub assembly (444), such that the rotary power transmitted to the main cam plate (442) by the electric motor (108) is supplied to the propeller shaft (236), and the main coupler hub assembly (444) remains stationary.
40. The hybrid electric drive system (106) as claimed in claim 38, wherein in the combined mode of operation:
the ECU is configured to enable generation of the rotary power by the IC engine assembly (118),
the motor controller (112) is configured to enable generation of the rotary power by the electric motor (108),
the set of rollers and springs (446, 448) is adapted to connect the linkage between the main cam plate (442) and the main coupler hub assembly (444), such that the rotary power transmitted to the drive shaft (240) by the IC engine assembly (118) is supplied to the main coupler hub assembly (444), and the rotary power generated by the electric motor (108) is supplied to the main cam plate (442), and
the controller (122) maintains the rotational speed of the main cam plate (442) driven by the electric motor (108) to be less than the rotational speed of the main coupler hub assembly (444) driven by the IC engine assembly (118) to enable the rotary power generated by both the IC engine assembly (118) and the electric motor (108) to be combined and seamlessly transmitted to the propeller shaft (236) to drive the set of wheels (102/104).
41. The hybrid electric drive system (106) as claimed in claim 32, wherein the vehicle comprises a combined accelerator (220) configured with the electric motor (108) and the IC engine assembly (118) to enable the electric motor (108) to speed up earlier than the IC engine assembly (118) owing to high initial starting torque of the electric motor (108), in the combined mode of operation.
42. The hybrid electric drive system (106) as claimed in claim 38, wherein in the reverse mode of operation:
the ECU enables generation of the rotary power by the IC engine assembly (118) to rotate the drive shaft (240) in a reverse direction,
the motor controller (112) disables generation of the rotary power by the electric motor (108),
the set of rollers and springs (446, 448) is adapted to disconnect the linkage between the main coupler hub assembly (444) and the main cam plate (442), and
the shaft coupler (418) is configured to directly transmit the rotary power from the drive shaft (240) rotating in the reverse direction to the propeller shaft (236).
43. The hybrid electric drive system (106) as claimed in claim 32, wherein the shaft coupler (418) comprises:
a third cam plate (434) fixedly coupled with the shaft coupler (418); and
a third set of rollers and springs (436, 438) configured with one or more recesses of the third cam plate (434) to regulate linkage between the shaft coupler (418) and a hub (432) of the drive shaft (240), wherein
the third set of rollers and springs (436, 438) is configured to connect the linkage between the third cam plate (434) of the shaft coupler (418) and the hub (432) of the drive shaft (240) rotating in the reverse direction, in the reverse mode of operation, such that the rotary power transmitted to the drive shaft (240) by the IC engine assembly (118) is supplied to the propeller shaft (236) that rotates with the same speed and direction as the drive shaft (240).
44. The hybrid electric drive system (106) as claimed in claim 41, wherein the controller (122) is operatively connected to the combined accelerator (220) to enable propulsion of the vehicle in the highest efficiency zone of either of the IC engine assembly (118) and the electric motor (108) in the combined mode of operation.
45. The hybrid electric drive system (106) as claimed in claim 32, wherein in the engine mode of operation, the rotary power transmitted to the set of wheels (102/104) is supplied to the electric motor (108) through the over-running clutch drive unit (110) to enable a battery pack (114) configured with electric motor (108) to be charged.
46. The hybrid electric drive system (106) as claimed in claim 35, wherein the vehicle (100) comprises a fuelling assembly having a hydrogen fuel cells stack and a liquid hydrogen tank configured to supply electrical energy to operate the electric motor (108), wherein the hydrogen fuel cells stack, the liquid hydrogen tank and the battery pack (114) is mounted on the chassis of the vehicle (100).
47. The hybrid electric drive system (106) as claimed in claim 32, wherein the electric motor (108) is configured to receive electrical energy from a stack of ultra-capacitors.
48. A vehicle (100) comprising the hybrid electric drive system (106) as claimed in claim 32.