Description:FIELD OF THE INVENTION
[001] The present invention generally relates a propulsion system in a vehicle. More particularly, the present invention relates to the propulsion system and a method of operating the propulsion system.

BACKGROUND OF THE INVENTION
[002] In recent past, vehicles with hybrid propulsion systems are prevalent. The hybrid propulsion systems comprise an Internal Combustion Engine (ICE) along with an electrical machine. The electrical machine, such as an Integrated-Starter Generator (ISG), is adapted to selectively assists the ICE for catering to various performance and/or efficiency requirements in the vehicle.
[003] The hybrid propulsion systems are typically operated at various operating modes such as an engine mode and a mild-hybrid assist mode. For switching the hybrid propulsion system from an engine mode to the mild hybrid assist mode, an abrupt actuation of a throttle member is generally performed. In the mild-hybrid assist mode, a drive torque from the electric machine is transferred to the wheels along with the motive force from the ICE, thereby reducing a fuel consumption in the ICE. Consequently, fuel economy of the vehicle is improved. However, such abrupt actuation of the throttle member results in an increase in a rate of discharge of a battery. Such a scenario results in rapid depletion of the battery, which may affect life of the battery. Moreover, if a total number of times the hybrid assist mode is activated due to abrupt actuation of the throttle member exceeds a predetermined limit, the battery may be drained beyond a threshold value, rendering damage to the battery, which is undesirable. Additionally, a rider of the vehicle is typically unaware on when the vehicle is operated in the mild-hybrid assist mode. As such, the rider may be incapable of controlling activation or de-activation of the mild-hybrid assist mode. Furthermore, the mild-hybrid assist mode is operated based on the abrupt actuation of the throttle member at a lower speed threshold of the vehicle. Thus, in conventional vehicles, the rider is required to decelerate the vehicle to the lower speed threshold and then abruptly or suddenly increase the throttle member for activating the mild-hybrid assist mode, which may not effective during maneuverings such as overtaking of other vehicles.
[004] In view of the above, there is a need for a propulsion system and a method of operating the propulsion system, which addresses one or more limitations stated above.

SUMMARY OF THE INVENTION
[005] In one aspect, a propulsion system in a vehicle is provided. The propulsion system comprises an internal combustion engine (ICE) comprising a crankshaft coupled to at least one wheel of the vehicle. The crankshaft is adapted to provide motive force to the at least one wheel for movement of the vehicle. An electric machine is coupled to the crankshaft of the ICE and to a battery unit, wherein the electric machine is adapted to be operated in an assist mode to provide a drive torque to the crankshaft for assisting the ICE. One or more sensors are disposed in the vehicle. Each of the one or more sensors is capable of sensing one or more operating parameters of the vehicle. An assist mode switch is communicably coupled to the electric machine. The assist mode switch is operable between an engaged state and a disengaged state. A control unit is communicably coupled to the electric machine, the battery unit, the assist mode switch and the one or more sensors. The control unit is configured to receive, the one or more operating parameters of the vehicle from the one or more sensors. The drive torque to be provided by the electric machine to the crankshaft is then determined for assisting the ICE based on at least one of the one or more operating parameters and a condition of the assist mode switch. The electric machine is then operated in the assist mode for providing the drive torque to the crankshaft for assisting the ICE.
[006] In an embodiment, the one or more operating parameters comprise an ignition condition of the vehicle, a State of Charge (SOC) of the battery unit and an engine speed of the ICE.
[007] In an embodiment, the control unit is adapted to determine the drive torque to be provided to the crankshaft, when the vehicle is in the ignition ON condition, the SOC of the battery unit is above a predetermined value and the engine speed is between a predefined range.
[008] In an embodiment, the control unit is adapted to provide an indication to a rider of the vehicle for operating the electric machine in the assist mode.
[009] In an embodiment, the control unit is adapted to provide the indication to the rider through an instrument cluster of the vehicle, wherein the instrument cluster is adapted to provide the indication to the rider through at least one of a visual indication, an audible indication and a haptic indication.
[010] In an embodiment, the control unit operates the electric machine in the assist mode upon manual actuation of the assist mode switch to the engaged state by the rider.
[011] In an embodiment, the control unit is adapted to operate the electric machine in the assist mode from the passive mode, during an abrupt actuation of a throttle member of the vehicle.
[012] In an embodiment, the control unit is adapted to determine supply of the drive torque to the crankshaft in a preceding assist mode from the electric machine. The preceding assist mode is operated before a predefined time duration. The control unit is adapted to operate the electric machine in the assist mode upon determining absence of the preceding assist mode of the electric machine.
[013] In an embodiment, the electric machine is an Integrated Starter Generator (ISG) machine.
[014] In an embodiment, the control unit operates the electric machine in a regenerative braking mode upon detection of actuation of a brake member of the vehicle. The electric machine in the regenerative braking mode being capable of generating and supplying an electric current to the battery unit for charging.
[015] In an embodiment, the electric machine in the passive mode being adapted to generate and supply an electric current to the battery unit for charging.
[016] In another aspect, a method for operating a propulsion system of a vehicle. The method comprising receiving, by the control unit, the one or more operating parameters of the vehicle from the one or more sensors. The drive torque to be provided by the electric machine to the crankshaft is then determined for assisting the ICE based on at least one of the one or more operating parameters and the condition of the assist mode switch. The electric machine is then operated in the assist mode for providing the drive torque to the crankshaft for assisting the ICE.

BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 is a block diagram of a propulsion system in a vehicle, in accordance with an exemplary embodiment of the present invention.
Figure 2 is a block diagram of a control unit of the propulsion system, in accordance with an exemplary embodiment of the present invention.
Figure 3 is a flow diagram of a method of operating the propulsion system through actuation of an assist mode switch, in accordance with an exemplary embodiment of the present invention.
Figure 4 is a flow diagram of a method of operating the propulsion system, in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[017] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder.
[018] Figure 1 is a block diagram of a propulsion system 100 in a vehicle, in accordance with an exemplary embodiment of the present invention. The propulsion system 100 is adapted to prevent deep discharging of a battery unit 106 of the vehicle, thereby enhancing life of the battery unit 106. In the present embodiment, the vehicle can be a two-wheeled vehicle, a three-wheeled vehicle or a multi-wheeled vehicle.
[019] The propulsion system 100 comprises an internal combustion engine (ICE) 102. The ICE 102 comprises a crankshaft (not shown) coupled to at least one wheel (not shown) of the vehicle. The crankshaft is adapted to provide motive force to the at least one wheel for movement of the vehicle. In an embodiment, the crankshaft is coupled to the at least one wheel of the vehicle through a transmission assembly (not shown). An electric machine 104 is coupled to the crankshaft of the ICE 102 and to the battery unit 106. The electric machine 104 is adapted to generate a drive torque through electrical energy received from the battery unit 106. The electric machine 104 is adapted to provide the drive torque to the crankshaft for assisting the ICE 102, when the electric machine 104 is operated in an assist mode. In an embodiment, the electric machine 104 is coupled to the crankshaft of the ICE 102 through conventional coupling means known in the art for enabling supply of the drive torque to the crankshaft.
[020] In the present embodiment, the electric machine 104 is an Integrated-Starter Generator (ISG) machine. In another embodiment, the electric machine 104 may be an electromagnetic machine capable of supplying the drive torque to the crankshaft for operating the propulsion system 100 in the assist mode. The electric machine 104 may also enable charging of the battery unit 106, when rotational energy is transferred from the crankshaft or from the at least one wheel to the electric machine 104.
[021] In the present embodiment, the term ‘assist mode’ pertains to a mode of the electric machine 104 for supplying of the drive torque to the ICE 102, a part of which may be used for operation of the ICE 102 and while other part of the drive torque may be supplied to the at least one wheel of the vehicle. As such, in the assist mode, the drive torque from the electric machine 104 and the motive force from the ICE 102 are supplied to the at least one wheel. Therefore, the assist mode of the propulsion system 100 may also be termed as ‘a hybrid mode’, wherein power generated in both the ICE 102 and the electric machine 104 are supplied to the at least one wheel for movement of the vehicle. Since, a part of the drive torque is used for operating the ICE 102, a reduced quantity of fuel is consumed by the ICE 102 for operation, thereby enhancing fuel efficiency of the ICE 102.
[022] In an embodiment, the propulsion system 100 is capable of being operated in an engine mode and the assist mode. In the engine mode, the propulsion system 100 supplies the motive force or power only from the ICE 102 to the at least one wheel of the vehicle. During the engine mode of the propulsion system 100, the electric machine 104 operates in a passive mode. In the passive mode, a rotor component (not shown) in the electric machine 104 may be rotated along with the crankshaft. The rotation of the rotor component in the electric machine 104 generates electrical energy, which is supplied to the battery unit 106 for charging. Thus, during the engine mode, the electric machine 104 operates in the passive mode, while also charging the battery unit 106, in order to maintain sufficient SOC in the battery unit 106 for operation in the assist mode.
[023] In an embodiment, the propulsion system 100 is also capable of being operated in a regenerative braking mode. In the regenerative braking mode, during braking of the vehicle, kinetic energy or rotational energy from the wheels of the vehicle is transferred to the electric machine 104 through an energy transfer mechanism (not shown) in the transmission system. The rotor component rotates upon receiving the kinetic energy from the wheels of the vehicle. The rotation of the rotor component in the electric machine 104 generates electrical energy, which is supplied to the battery unit 106 for charging.
[024] Further, the propulsion system 100 comprises one or more sensors 108 disposed in the vehicle. Each of the one or more sensors 108 is capable of sensing one or more operating parameters of the vehicle. The term “operating parameters” pertains to parameters or factors that are involved in operating the vehicle. In an embodiment, the one or more operating parameters comprises an ignition condition of the vehicle, a State of Charge (SOC) of the battery unit 106, and an engine speed of the ICE 102.
[025] In an embodiment, the one or more sensors 108 comprises an ignition sensor 108a (shown in Figure 2), an SOC sensor 108b (shown in Figure 2) and an engine speed sensor 108c (shown in Figure 2). In an embodiment, the ignition sensor 108a is disposed in an ignition device (not shown) of the vehicle. The ignition sensor 108a is adapted to monitor an ignition condition of the vehicle. That is, the ignition sensor 108a is adapted to monitor an ignition ON condition or an ignition OFF condition of the vehicle. In an embodiment, the SOC sensor 108b may be disposed within the battery unit 106 and is adapted to monitor the SOC of the battery unit 106. In another embodiment, the engine speed sensor 108c is mounted on the crankshaft of the ICE 102, and is adapted to monitor speed of rotation of the crankshaft. The speed of rotation of the crankshaft is determined as the engine speed by the engine speed sensor 108c.
[026] In another embodiment, the one or more operating parameters may comprise a throttle position of a throttle member (not shown) of the vehicle and a speed of the vehicle. Accordingly, a throttle-position sensor 108d (shown in Figure 2) and a vehicle speed sensor (not shown) is provided in the vehicle. In an embodiment, the throttle-position sensor 108d is mounted on the throttle member of the vehicle. The throttle-position sensor 108d is adapted to monitor a rate of change of a throttle position in the throttle member. The throttle-position sensor 108d is also adapted to monitor abrupt movement or sudden movement of the throttle member. In another embodiment, the vehicle speed sensor is disposed in a wheel (not shown) of the vehicle. The vehicle speed sensor is adapted to monitor the speed of rotation of the wheel, for determining the speed of the vehicle.
[027] The propulsion system 100 also comprises an assist mode switch 114 disposed in the vehicle. In an embodiment, the assist mode switch 114 may be disposed on a handlebar (not shown), or in an instrument cluster 112 or a steering member (not shown) of the vehicle. The assist mode switch 114 is communicably coupled to the electric machine 104, and is operable between an engaged state (not shown) and a disengaged state (not shown). In an embodiment, the assist mode switch 114 may be a push-button switch operable between the engaged state and the disengaged state.
[028] Referring to Figure 2 in conjunction with Figure 1, the propulsion system 100 comprises a control unit 110 communicably coupled to the electric machine 104, the battery unit 106, the assist mode switch 114 and to each of the one or more sensors 108. In an embodiment, the control unit 110 is communicably coupled to the electric machine 104, the battery unit 106, the assist mode switch 114 and to each of the one or more sensors 108 through a wired connection or a wireless connection as per design feasibility and requirement. The control unit 110 is adapted to control the assist mode for enabling selective supply of the drive torque from the electric machine 104 to the crankshaft for assisting the ICE 102.
[029] In an embodiment, the control unit 110 is a control unit disposed in the electric machine 104 and be communicably coupled with the electric machine 104. In another embodiment, the control unit 110 is disposed outside the electric machine 104 and be communicably coupled with the electric machine 104. In an embodiment, the control unit 110 can be in communication with at least one vehicle control unit (not shown) of the vehicle. Accordingly, the control unit 110 may obtain data pertaining to the one or more operating parameters of the vehicle, i.e. the ignition condition of the vehicle, the SOC of the battery unit 106 and the engine speed of the vehicle from the at least one vehicle control unit. In an embodiment, the control unit 110 may comprise one or more additional components such as, but not limited to, an input/output module 120, a processing module 122, and an analytic module 124.
[030] The control unit 110 is in communication with the components such as the processing module 122 and the analytic module 124. In an embodiment, the processing module 122 and the analytic module 124 are configured within the control unit 110. In another embodiment, the control unit 110 may be embodied as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and one or more single core processors. For example, the control unit 110 is embodied as one or more of various processing devices or modules, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as but not limited to, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like. In yet another embodiment, the control unit 110 may be configured to execute hard-coded functionality. In still another embodiment, the control unit 110 may be embodied as an executor of instructions, where the instructions are specifically configured to the control unit 110 to perform steps or operations described herein for operating the propulsion system 100.
[031] Further, the control unit 110 is communicably coupled to a memory unit 126. The memory unit 126 is capable of storing information processed by the control unit 110 for operating the propulsion system 100 and the data procured by each of the one or more sensors 108. In an embodiment, the memory unit 126 may be integrated within the control unit 110.
[032] In an embodiment, the memory unit 126 is embodied as one or more volatile memory devices, one or more non-volatile memory devices and/or combination thereof, such as magnetic storage devices, optical-magnetic storage devices and the like as per design feasibility and requirement. The memory unit 126 communicates with the control unit 110 via suitable interfaces such as Advanced Technology Attachment (ATA) adapter, a Serial ATA [SATA] adapter, a Small Computer System Interface [SCSI] adapter, a network adapter or any other component enabling communication between the memory unit 126 and the control unit 110. In an embodiment, the control unit 110 may be connected to a power supply such as the battery unit 106, for receiving electrical power. In an embodiment, the control unit 110 may have an inbuilt power supply 128 for drawing power from the battery unit 106.
[033] In an embodiment, the control unit 110 or the analytic module 124 of the control unit 110 is adapted to operate the propulsion system 100. Particularly, the control unit 110 or the analytic module 124 controls the assist mode of the electric machine 104 for controlling the supply of the drive torque to the crankshaft for assisting the ICE 102. The control unit 110 is adapted to control operation of the propulsion system 100 based on at least one of the condition or state of the one or more operating parameters of the vehicle and the condition or state of the assist mode switch 114. In other words, the control unit 110 is adapted to control operation of the propulsion system 100 based on three scenarios. The first scenario being based on the condition of the one or more operating parameters of the vehicle, the second scenario being based on condition of the assist mode switch 114 and the third scenario being based on both the condition of the one or more operating parameters and the condition of the assist mode switch 114. In an embodiment, condition of the assist mode switch 114 refers to the engaged state or the disengaged state of the assist mode switch 114. The control unit 110 or the analytic module 124, receives the one or more operating parameters of the vehicle from the one or more sensors 108. Upon receiving the one or more operating parameters from the one or more sensors 108, the control unit 110 monitors the ignition condition of the vehicle, the SOC of the battery unit 106 and the engine speed of the vehicle. When the vehicle is in the ignition ON condition, the SOC of the battery unit 106 is above a predetermined value and the engine speed is between a predefined range, the control unit 110 determines the drive torque to be supplied to the crankshaft by the electric machine 104. The determined drive torque is then supplied to the crankshaft from the electric machine 104, thereby operating the electric machine 104 in the assist mode.
[034] In an embodiment, apart from the conditions of the one or more operating parameters and/or the condition of the assist mode switch 114, the control unit 110 may also determine supply of the drive torque to the crankshaft in a preceding assist mode from the electric machine 104. The preceding assist mode may be the assist mode of the electric machine 104 that had been operated by the control unit 110 before a predefined time duration from the current cycle of analysis for actuating the assist mode. The control unit 110 is adapted to operate the electric machine 104 in the assist mode upon determining absence of the preceding assist mode of the electric machine 104. Therefore, apart from the conditions of the one or more operating parameters and/or the condition of the assist mode switch 114, the control unit 110 also considers the parameter of the preceding assist mode for operating the electric machine 104 in the assist mode. Such a consideration of the preceding assist mode further reduces the load on the battery unit 106 and thus mitigating deep draining of the battery unit 106. In an embodiment, the predefined time duration for absence of the preceding assist mode is 60 seconds. As an example, the control unit 110, during the current analysis for operating the assist mode, verifies whether the preceding assist mode was operated within the last 60 seconds. If the preceding assist mode was operated within last 60 seconds from the current analysis, the control unit 110 prevents operation of the current assist mode.
[035] In an embodiment, the control unit 110 is also adapted to compute a time duration for which the assist mode is to be operated. The time duration may be computed based on the SOC of the battery unit 106 and/or the drive torque requirement of the vehicle. In an embodiment, the time duration for the assist mode may be 30 seconds. Thus, the drive torque determined by the control unit 110 is supplied to the crankshaft for 30 seconds.
[036] In an embodiment, during the first scenario, the control unit 110 controls operation of the propulsion system 100 based on the one or more operating parameters of the vehicle. As such, in this scenario, the control unit 110 automatically operates the electric machine 104 in the assist mode upon determining the ignition ON condition, the SOC of the battery unit 106 being above the predetermined value and the engine speed being in-between the predefined range. Therefore, in this scenario, the control unit 110 operates the electric machine 104 in the assist mode automatically without a need for manual actuation of the assist mode switch 114. Such operation of the electric machine 104 by the control unit 110, enhances fuel efficiency of the vehicle, since this scenario typically occurs during the steady drive condition of the vehicle.
[037] In an embodiment, in the first scenario, the control unit 110 considers the parameter of the preceding assist mode along with the one or more operating parameters. Thus, in the first scenario, the control unit 110 automatically operates the electric machine 104 in the assist mode upon determining the ignition ON condition, the SOC of the battery unit 106 being above the predetermined value, the engine speed being in-between the predefined range and absence of the preceding assist mode before the predefined time duration from the current analysis.
[038] In an embodiment, during the second scenario, the control unit 110 controls operation of the propulsion system 100 based on the condition of the assist mode switch 114. Upon actuation of the assist mode switch 114 to the engaged state, the control unit 110 determines the ignition condition, the SOC of the battery unit 106 and the engine speed. At this juncture, when the control unit 110 determines the ignition ON condition, the SOC of the battery unit 106 being above the predetermined value and the engine speed being in-between the predefined range, the assist mode of the electric machine 104 is activated. Therefore, in this scenario, the control unit 110 operates the electric machine 104 in the assist mode manually upon actuation of the assist mode switch 114. Such operation of the control unit 110, enables a rider of the vehicle to control supply of the drive torque to the at least one wheel, thereby enhancing maneuverability of the vehicle especially during an overtaking maneuver.
[039] In an embodiment, in the second scenario, the control unit 110 also considers the parameter of the preceding assist mode along with the manual actuation of the assist mode switch 114. Thus, in the second scenario upon actuation of the assist mode switch 114 to the engaged state, the control unit 110 manually operates the electric machine 104 in the assist mode upon determining the ignition ON condition, the SOC of the battery unit 106 being above the predetermined value, the engine speed being in-between the predefined range and absence of the preceding assist mode before the predefined time duration from the current analysis.
[040] In an embodiment, during the third scenario, the control unit 110 controls operation of the propulsion system 100 based on the one or more operating parameters and the condition of the assist mode switch 114. In this scenario, the control unit 110 firstly determines the ignition condition, the SOC of the battery unit 106 and the engine speed. When the control unit 110 determines the ignition ON condition, the SOC of the battery unit 106 being above the predetermined value and the engine speed being in-between the predefined range, an indication may be provided to the rider to indicate availability of the assist mode. At this juncture, when the rider manually operates the assist mode switch 114 to the engaged state, the control unit 110 operates the electric machine 104 in the assist mode.
[041] In an embodiment, in the third scenario, the control unit 110 also considers the parameter of the preceding assist mode along with the one or more operating parameters and the condition of the assist mode switch 114. Thus, in the third scenario upon actuation of the assist mode switch 114 to the engaged state, the control unit 110 manually operates the electric machine 104 in the assist mode upon determining the ignition ON condition, the SOC of the battery unit 106 being above the predetermined value, the engine speed being in-between the predefined range and absence of the preceding assist mode before the predefined time duration from the current analysis.
[042] In an embodiment, the indication provided to the rider by the control unit 110 may be through the instrument cluster 112 of the vehicle. The instrument cluster 112 may be adapted to provide the indication to the rider through at least one of a visual indication, an audible indication and a haptic indication. In an embodiment, the visual indication may be provided through a display icon in the instrument cluster 112. In another embodiment, the instrument cluster 112 may be communicably coupled to a sound emitting device (not shown) such as an alarm device, for providing the audible alert to the rider. In another embodiment, the instrument cluster 112 may be communicably coupled to haptic devices disposed on the handlebar or the steering device of the vehicle for providing the haptic feedback to the rider.
[043] In an embodiment, the indication provided by the instrument cluster 112 may be to indicate availability of the assist mode in the propulsion system 100 or to indicate the rider that the vehicle is being operated in the assist mode. As such, the availability and/or the activation of the assist mode is notified to the rider of the vehicle.
[044] In an embodiment, the control unit 110 may operate the electric machine 104 in the assist mode during an abrupt actuation of the throttle member 116. In this scenario, the control unit 110 construes that abrupt actuation of the throttle member 116 is carried out due to demand for additional torque to the rider for maneuvering the vehicle. Upon abrupt actuation of the throttle member 116, the control unit 110 operates the electric machine 104 in the assist mode, upon determining the ignition ON condition, the SOC of the battery unit 106 being above the predetermined value and the engine speed being in-between the predefined range. Thus, in this scenario, the control unit 110 may bypass the state pertaining to the assist mode switch 114 for operating the electric machine 104 in the assist mode.
[045] In an embodiment, the control unit 110 may determine abrupt or sudden actuation of the throttle member 116 through the throttle-position sensor 108d. The control unit 110 determines the abrupt actuation of the throttle member 116, when the throttle-position sensor 108d determines a large opening of the throttle member 116 within a short duration of time. As an example, the control unit 110 determines abrupt actuation of the throttle member 116, when the throttle-position sensor 108d determines the opening of the throttle member 116 as 20 degrees in one second.
[046] In an embodiment, the predetermined value of the SOC of the battery unit 106 may be 10% of a maximum SOC (i.e. 100%) of the battery unit 106. Since, the control unit 110 monitors the SOC of the battery unit 106 and allows supply of electrical energy from the battery unit 106 to the electric machine 104 only when the SOC is above the predetermined value, deep draining or critical draining of the battery unit 106 is prevented. Thus, enhancing life of the battery unit 106.
[047] In an embodiment, the predefined range of the engine speed may be 2000 rpm to 5500 rpm. The predefined range of the engine speed ensures that the vehicle is operating in a steady drive condition.
[048] In an embodiment, the control unit 110 operates the electric machine 104 in the regenerative braking mode upon detection of actuation of a brake member 118 of the vehicle. As such, upon detecting actuation of the brake member 118, the energy transfer mechanism couples the electric machine 104 with the at least one wheel. The coupling of the electric machine 104 with the at least one wheel, enables transfer of kinetic energy from the at least one wheel to the rotor component, thereby rotating the rotor component. The rotation of the rotor component in the electric machine 104 generates electrical energy, which is supplied to the battery unit 106 for charging. In an embodiment, the brake member 118 may be a brake lever or a brake pedal of the vehicle.
[049] Referring to Figure 3, a flow diagram of a method 300 for controlling operation of the propulsion system 100 during the engaged state of the assist mode switch 114 is depicted.
[050] At step 302, the control unit 110 receives the ignition condition of the vehicle from the ignition sensor 108a (shown in Figure 2). When the vehicle is in the ignition ON condition, the control unit 110 moves to step 304, wherein the condition of the assist mode switch 114 is monitored. The method 300 moves to step 306, when the assist mode switch 114 is operated to the engaged state by the rider.
[051] At step 306, the control unit 110 receives SOC of the battery unit 106 from the SOC sensor 108b. When the SOC of the battery unit 106 is above the predetermined value, the method moves to step 310. When, the SOC of the battery unit 106 is below the predetermined value, the method 300 moves to step 308 and prevents entry to the assist mode. Thus, operation of the electric machine 104 in the assist mode is prevented, when the SOC is below the predetermined value.
[052] At step 310, the control unit 110 receives the engine speed data from the engine speed sensor 108c. When the engine speed is in the predefined range, the method moves to step 314. When the engine speed is less then or above the predefined range, the method moves to step 312 and prevents entry to the assist mode of the electric machine 104.
[053] At step 314, the control unit 110 monitors presence or absence of the preceding assist mode for the predetermined time duration. When the preceding assist mode is found to be absent for the predetermined time duration, the control unit 110 proceeds to step 318 for operating the electric machine 104 in the assist mode and provide the drive torque to the ICE 102. When the preceding assist mode is found to be present, an indication may be provided to the rider at step 316. At step 316, the rider may engage the assist mode switch 114 for manually operating the electric machine 104 in the assist mode
[054] Referring to Figure 4 a flow diagram of a method 400 for controlling operation of the propulsion system 100 is depicted.
[055] At step 402, the control unit 110 receives the one or more operating parameters of the vehicle from the one or more sensors 108. The control unit 110 monitors the ignition condition of the vehicle, the SOC of the battery unit 106 and the engine speed of the vehicle. Thereafter, the control unit 110 determines that the vehicle is in the ignition ON condition, the SOC of the battery unit 106 is above the predetermined value and the engine speed is between the predefined range. At this scenario, the method 400 proceeds to step 404.
[056] At step 404, the control unit 110 determines the drive torque to be supplied to the crankshaft by the electric machine 104. The drive torque to be provided by the electric machine 104 to the crankshaft for assisting the ICE 102 is determined based on at least one of the condition or state of the one or more operating parameters of the vehicle and the condition of the assist mode switch 114, as already mentioned in description pertaining to Figure 2.
[057] At step 406, the control unit 110 operates the electric machine 104 by supplying the determined drive torque to the crankshaft, thereby operating the electric machine 104 in the assist mode. In an embodiment, the control unit 110 is also adapted to compute the time duration for which the assist mode is to be operated. The time duration may be computed based on the SOC available and/or the drive torque requirement of the vehicle.
[058] The claimed invention as disclosed above is not routine, conventional or well understood in the art, as the claimed aspects enable the following solutions to the existing problems in conventional technologies. Specifically, the claimed aspect of operating the propulsion system based on at least one of the one or more operating parameters and the assist mode switch prevents deep or critical drain of the battery unit, while ensuring that the technique is simple. Also, the technique of operating the propulsion system as claimed in the present invention is scalable to multi-wheeled vehicle. Moreover, determination of the operating parameters and the preceding assist mode reduces load or demand on the battery unit, thereby preventing deep drain and also enhance battery life. Consequently, durability of the battery unit is enhanced significantly. Moreover, the assist mode is capable of being operated for a predetermined time duration, thereby preventing fast discharge of the battery unit. Additionally, the propulsion system is also capable of being operated based on condition of the assist mode switch. Thus, the additional power or drive torque is made readily available to the rider by the present invention, and thus enhancing maneuverability of the vehicle, while also catering to performance requirements of the rider. Furthermore, the propulsion system is also capable of being operated to the assist mode through sudden or abrupt actuation of the throttle member, thereby further enhancing maneuverability of the vehicle. Also, indication to the rider about availability of the assist mode enables the rider to activate the assist mode during a requirement. Further, the indication to the rider about the propulsion system being operated in the assist mode enhances confidence in the rider during maneuverability of the vehicle, such as overtaking.

Reference numerals

100 - Propulsion system
102 - Internal Combustion Engine
104 - Electric machine
106 - Battery unit
108 - One or more sensors
108a - Ignition sensor
108b - SOC sensor
108c - Engine speed sensor
108d - Throttle-position sensor
110 - Control unit
112 - Instrument cluster
114 - Assist mode switch
116 - Throttle member
118 - Brake member
120 - Input/Output module
122 - Processing module
124 - Analytic module
126 - Memory unit
128 - Power supply
, Claims:1. A propulsion system (100) in a vehicle, the propulsion system (100) comprising:
an internal combustion engine (ICE) (102) comprising a crankshaft coupled to at least one wheel of the vehicle, the crankshaft being adapted to provide motive force to the at least one wheel for movement of the vehicle;
an electric machine (104) coupled to the crankshaft of the ICE (102) and to a battery unit (106), wherein the electric machine (104) being adapted to be operated in an assist mode to provide a drive torque to the crankshaft for assisting the ICE (102);
one or more sensors (108) disposed in the vehicle, each of the one or more sensors (108) being capable of sensing one or more operating parameters of the vehicle;
an assist mode switch (114) communicably coupled to the electric machine (104), the assist mode switch (114) being operable between an engaged state and a disengaged state; and
a control unit (110) communicably coupled to the electric machine (104), the battery unit (106), the assist mode switch (114) and the one or more sensors (108), the control unit (110) being configured to:
receive, the one or more operating parameters of the vehicle from the one or more sensors (108);
determine, the drive torque to be provided by the electric machine (104) to the crankshaft for assisting the ICE (102) based on at least one of the one or more operating parameters and a condition of the assist mode switch (114); and
operate, the electric machine (104) in the assist mode for providing the drive torque to the crankshaft for assisting the ICE (102).

2. The propulsion system (100) as claimed in claim 1, wherein the one or more operating parameters comprise of:
an ignition condition of the vehicle;
a State of Charge (SOC) of the battery unit (106); and
an engine speed of the ICE (102).

3. The propulsion system (100) as claimed in claim 2, wherein the control unit (110) being adapted to determine the drive torque to be provided to the crankshaft, when the vehicle being in the ignition ON condition, the SOC of the battery unit (106) being above a predetermined value, and the engine speed being between a predefined range.

4. The propulsion system (100) as claimed in claim 1, wherein the control unit (110) being adapted to provide an indication to a rider of the vehicle for operating the electric machine (104) in the assist mode.

5. The propulsion system (100) as claimed in claim 4, wherein the control unit (110) being adapted to provide the indication to the rider through an instrument cluster (112) of the vehicle, wherein the instrument cluster (112) being adapted to provide the indication to the rider through at least one of a visual indication, an audible indication and a haptic indication.

6. The propulsion system (100) as claimed in claim 4, wherein the control unit (110) operates the electric machine (104) in the assist mode upon manual actuation of the assist mode switch (114) to an engaged state by the rider.

7. The propulsion system (100) as claimed in claim 1, wherein the control unit (110) being adapted to operate the electric machine (104) in the assist mode from a passive mode, during an abrupt actuation of a throttle member (116) of the vehicle, wherein the electric machine (104) in the passive mode being adapted to generate and supply an electric current to the battery unit (106) for charging.

8. The propulsion system (100) as claimed in claim 1, wherein the control unit (110) being adapted to determine supply of the drive torque to the crankshaft in a preceding assist mode from the electric machine (104), the preceding assist mode being operated before a predefined time duration,
the control unit (110) being adapted to operate the electric machine (104) in the assist mode upon determining absence of the preceding assist mode of the electric machine (104).

9. The propulsion system (100) as claimed in claim 1, wherein the electric machine (104) being an Integrated Starter Generator (ISG) machine.

10. The propulsion system (100) as claimed in claim 1, wherein the control unit (110) operates the electric machine (104) in a regenerative braking mode upon detection of actuation of a brake member (118) of the vehicle,
the electric machine (104) in the regenerative braking mode being capable of generating and supplying an electric current to the battery unit (106) for charging.

11. A method (400) for operating a propulsion system (100) of a vehicle, the method (400) comprising:
receiving (402), by a control unit (110), one or more operating parameters of the vehicle from the one or more sensors (108);
determining (404), by the control unit (110), a drive torque to be provided by an electric machine (104) to a crankshaft for assisting an internal combustion engine (ICE) (102) based on at least one of the one or more operating parameters and a condition of an assist mode switch (114) in the vehicle; and
operating (406), by the control unit (110), the electric machine (104) in an assist mode for providing the drive torque to the crankshaft for assisting the ICE (102).

12. The method (400) as claimed in claim 11, wherein the one or more operating parameters comprise of:
an ignition condition of the vehicle;
a State of Charge (SOC) of the battery unit (106); and
an engine speed of the ICE (102).

13. The method (400) as claimed in claim 12, wherein the control unit (110) being adapted to determine the drive torque to be provided to the crankshaft, when the vehicle being in the ignition ON condition, the SOC of the battery unit (106) being above a predetermined value and the engine speed being between a predefined range.

14. The method (400) as claimed in claim 11 comprising providing, by the control unit (110), an indication to a rider of the vehicle for operating the electric machine (104) in the assist mode, the indication being provided to the rider through an instrument cluster (112) of the vehicle, wherein the instrument cluster (112) being adapted to provide the indication to the rider through at least one of a visual indication, an audible indication and a haptic indication.

15. The method (400) as claimed in claim 14 comprising operating, by the control unit (110), the electric machine (104) in the assist mode upon manual actuation of the assist mode switch (114) to an engaged state by the rider.

16. The method (400) as claimed in claim 11 comprising operating, by the control unit (110), the electric machine (104) in the assist mode from a passive mode during an abrupt actuation of a throttle member (116) of the vehicle, wherein the electric machine (104) in the passive mode being adapted to generate and supply an electric current to the battery unit (106) for charging.

17. The method (400) as claimed in claim 11 comprising determining, by the control unit (110), supply of the drive torque to the crankshaft in a preceding assist mode from the electric machine (104), the preceding assist mode being operated before a predefined time duration,
the control unit (110) being adapted to operate the electric machine (104) in the assist mode upon determining absence of the preceding assist mode of the electric machine (104).

18. The method (400) as claimed in claim 11 comprising operating, by the control unit (110), the electric machine (104) in a regenerative braking mode upon detection of actuation of a brake member (118) of the vehicle,
the electric machine (104) in the regenerative braking mode being capable of generating and supplying an electric current to the battery unit (106) for charging.