DESC:TECHNICAL FIELD
[0001] The present disclosure relates to an internal combustion (IC) engine system for a vehicle. Particularly, the present disclosure relates to an internal combustion (IC) engine system operable on 100 percent methanol fuel at high efficiency without the need for any other fuel blend or additives.

BACKGROUND
[0002] The information in this section merely provides background information related to the present disclosure and may not constitute prior art(s) for the present disclosure.
[0003] In view of concerns related to the environment and India’s energy security, there is a serious need for alternate and clean fuels for the transportation sector. Several fuels, such as ethanol, methanol and even hydrogen, are being considered and promoted by the official agencies.
[0004] Methanol is one of the alternative fuels for gasoline which has multiple production pathways including production from bio-based raw materials. Methanol can also be produced from coal in countries which have abundant coal resources. Methanol can also be produced from high-ash coal which cannot be used efficiently in coal-based power plants. Syngas produced from many sources, such as biomass, high-ash coal, etc., is further processed to produce methanol. Thus, local production of methanol and use as an alternative fuel reduces the fuel imports and also solves energy security concerns.
[0005] Most of the work with methanol use in internal combustion (IC) engines has been on gasoline engines owing to its properties being suitable for use in a gasoline engine by blending a percentage of methanol in gasoline. In general, improvement in brake thermal efficiency (BTE) has been reported with methanol blending. Regulated emissions such as unburnt hydrocarbons (UHC), carbon monoxide (CO) and oxides of nitrogen (NOx) are observed to reduce with methanol blending. Thus, methanol as a fuel for IC engines shows many advantages and provides motivation for the present study.
[0006] Indian Patent Application No. 202141044970 (hereinafter referred to as “IN’970”) is directed to supply of methanol through a carburetor and injection of cottonseed oil in the engine cylinder and demonstrate reduction in particulate emissions and NOx emissions. However, IN’970 uses two fuels and uses a carbureted system which do not have strict control on fuel supply quantity. Also, IN’970 does not use 100% methanol for engine operation.
[0007] Further, Indian Patent Application No. 202241038960 discloses use of CNG, diesel and methanol fuels in a diesel engine; however, does not demonstrate use of 100% methanol and does not use spark ignition technology.

OBJECTS OF THE INVENTION
[0008] An object of the present disclosure is to provide an internal combustion engine that operates on 100 percent methanol fuel without the need for additional fuel blends or additives.
[0009] An object of the present disclosure is to provide a fuel injection system that facilitates the precise injection of methanol fuel into the engine cylinders, ensuring optimal combustion and overall system efficiency.
[0010] An object of the present disclosure is to enhance the brake thermal efficiency of the internal combustion engine system.
[0011] An object of the present disclosure is to provide a design that allows for the integration of the internal combustion engine system into existing vehicle platforms with minimal modifications, facilitating the transition to methanol-based fuel.

SUMMARY
[0012] Aspects of the present disclosure relates to an internal combustion (IC) engine system operable on 100 percent methanol fuel at high efficiency without the need for any other fuel blend or additives.
[0013] In an aspect, a fuel injection system for an internal combustion engine is disclosed. The fuel injection system includes a methanol tank, a pressure regulation valve disposed downstream of a fuel pump for adjusting a pressure of methanol fuel supplied to the fuel injectors; a fuel rail coupled to the fuel pump for receiving and storing pressurized methanol fuel to be supplied to the plurality of engine cylinders, via the fuel injectors; and a plurality of electronically controlled fuel injectors housed in the fuel rail and configured to supply methanol fuel into an intake manifold of the internal combustion engine.
[0014] In an embodiment, the fuel injectors are configured to be controlled by an engine control unit based on operational parameters of the internal combustion engine, and the fuel injection system is configured to inject 100 percent methanol fuel
[0015] In an embodiment, the fuel injection system includes a fuel return line adapted to return leaked methanol fuel from the pressure regulation valve to the methanol tank.
[0016] In an embodiment, the plurality of fuel injectors has an orifice size of about 500 µm and a flow rate of 970 cc/min at 3 bar of injection pressure.
[0017] In an embodiment, the plurality of fuel injectors are liquid spray nozzles configured to obtain the required drop size distribution, thereby aid in the rapid evaporation of the droplets and preparation of a homogeneous air-fuel mixture.
[0018] In an embodiment, the pressure regulation valve is configured to maintain the pressure of methanol fuel in the fuel rail in the range of 0 to 8 bar.
[0019] In an embodiment, the fuel return line is made of material compatible with methanol, comprising any or a combination of stainless steel and Teflon.
[0020] In another aspect of the present disclosure an internal combustion engine system for vehicles is disclosed. The disclosed engine include an internal combustion (IC) engine with a plurality of engine cylinders, each comprising a reciprocating piston; an intake manifold fluidly coupled to the plurality of engine cylinders via respective intake ports, configured to receive pressurized and cooled air from an engine air induction system, and an engine air induction system is coupled to the intake manifold, including a turbocharger driven by exhaust gases of the IC engine, configured to compress and increase the pressure of air supplied to the plurality of engine cylinders.
[0021] The engine further includes an exhaust manifold fluidly coupled to the plurality of engine cylinders via respective exhaust ports and an exhaust aftertreatment system coupled to the exhaust manifold for treating exhaust from the plurality of engine cylinders;
[0022] In an aspect, a fuel injection system coupled to the intake manifold, includes fuel injectors for supplying fuel into the intake manifold, and spark plugs for igniting air-fuel mixture. The fuel injection system is configured to inject 100% methanol fuel and an engine control unit configured to receive operational parameters via sensors, and control injection timing and duration of the fuel injectors, and ignition timing of the spark plugs.
[0023] In an embodiment, the engine control unit is configured to control injection timing and duration of the fuel injectors, and ignition timing of the spark plugs based on one or more parameters pertaining to estimated air trapped in each engine cylinder, IC engine speed, throttle positions, and time available during a suction stroke of each engine cylinder at the maximum speed of the IC engine.
[0024] In an embodiment, an air filter disposed upstream of the turbocharger, and is adapted to filter dust particles from the air entering the IC engine system.
[0025] In an embodiment, the IC engine has a compression ratio in the range of 10 to 12.
[0026] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF FIGURES
[0027] 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.
[0028] FIG. 1 is a schematic view of an internal combustion (IC) engine system of a vehicle, in accordance with an embodiment of the present disclosure;
[0029] FIG. 2 illustrates a comparison of engine torque and power obtained by the IC engine system (operable on methanol fuel) of FIG. 1 vis-à-vis that obtained by baseline CNG engines; and
[0030] FIG. 3 illustrates a comparison of brake thermal efficiency obtained by the IC engine system (operable on methanol fuel) of FIG. 1 vis-à-vis that obtained by baseline CNG engines.
[0031] Skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of embodiments of the present disclosure.

DETAILED DESCRIPTION
[0032] The one or more shortcomings of the prior art are overcome by the system as disclosed, and additional advantages are provided through the provision of the system as disclosed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the disclosure.
[0033] Pursuant to embodiments of the present disclosure, in an aspect, an internal combustion (IC) engine system of a vehicle is disclosed. The IC engine system includes an internal combustion (IC) engine with a plurality of engine cylinders, an intake manifold, an exhaust manifold, an engine air induction system, an exhaust aftertreatment system, a methanol fuel injection system, and an engine control unit. Each engine cylinder of the plurality of engine cylinders has a reciprocating piston therein. The intake manifold is fluidly coupled to the plurality of engine cylinders, via a respective intake port of each engine cylinder of the plurality of engine cylinders. The exhaust manifold is fluidly coupled to the plurality of engine cylinders, via a respective exhaust port of each engine cylinder of the plurality of engine cylinders. The engine air induction system is coupled to the intake manifold and adapted to supply air into the plurality of engine cylinders. The engine air induction system includes a turbocharger to compress and increase a pressure of air supplied to the plurality of engine cylinders. The exhaust aftertreatment system is coupled to the exhaust manifold and adapted to treat the exhaust received from the plurality of engine cylinders. The methanol fuel injection system is coupled to the intake manifold and adapted to supply methanol fuel to the plurality of engine cylinders. The methanol fuel injection system includes fuel injectors for supplying methanol fuel into the intake manifold, and spark plugs for igniting air-methanol fuel mixture. The engine control unit is configured to receive, via sensors, operational parameters of components of the IC engine. The engine control unit is further configured to control at least one of an injection timing and an injection duration of the fuel injectors, and an ignition time of the spark plug.
[0034] In another non-limiting embodiment of the present disclosure, the engine control unit controls the injection timing and the injection duration of the fuel injectors, and the ignition time of the spark plugs based on at least one of the estimated air trapped in each engine cylinder, IC engine speed, throttle positions, and time available during a suction stroke of each engine cylinder at maximum speed of the IC engine.
[0035] In another non-limiting embodiment of the present disclosure, the engine control unit sends signals to the fuel injectors and the spark plugs for controlling the injection timing and the injection duration of the fuel injectors and the ignition time of the spark plugs.
[0036] In another non-limiting embodiment of the present disclosure, the turbocharger of the engine air induction system is driven by exhaust gases of the IC engine.
[0037] In another non-limiting embodiment of the present disclosure, the turbocharger of the engine air induction system is adapted to compress air and increase the pressure of air above the atmospheric pressure.
[0038] In another non-limiting embodiment of the present disclosure, the turbocharger includes a rotary turbine driven by exhaust gases of the IC engine. The rotary turbine is coupled to a rotary compressor that increases the pressure of air above the atmospheric pressure.
[0039] In another non-limiting embodiment of the present disclosure, the engine air induction system includes an air filter disposed upstream of the turbocharger. The air filter is adapted to filter dust particles from the air entering the IC engine system.
[0040] In another non-limiting embodiment of the present disclosure, the engine air induction system includes an intercooler disposed downstream of the turbocharger. The intercooler is adapted to reduce the temperature of the compressed air exiting from the turbocharger.
[0041] In another non-limiting embodiment of the present disclosure, the engine air induction system includes an air throttle disposed downstream of the intercooler. The air throttle is adapted to control an amount of air entering the intake manifold and the plurality of engine cylinders, during suction.
[0042] In another non-limiting embodiment of the present disclosure, the fuel injectors of the methanol fuel injection system are methanol-compatible and electronically controlled fuel injectors.
[0043] In another non-limiting embodiment of the present disclosure, each of the spark plugs of the methanol fuel injection system produces a spark to ignite air-methanol fuel mixture in each engine cylinder at a specific time according to an activation signal sent by the engine control unit.
[0044] In another non-limiting embodiment of the present disclosure, the methanol fuel injection system includes a methanol tank for storing and supplying methanol fuel to the fuel injectors and the plurality of engine cylinders. The methanol tank is made of stainless steel, or methanol-compatible materials such as Teflon.
[0045] In another non-limiting embodiment of the present disclosure, the methanol fuel injection system includes a filter coupled to the methanol tank via a fuel line. The filter is adapted to filter particles of size 5 micrometers and above in methanol fuel.
[0046] In another non-limiting embodiment of the present disclosure, the methanol fuel injection system includes a fuel pump disposed downstream of the methanol tank, for supplying methanol fuel to the fuel injectors and the plurality of engine cylinders.
[0047] In another non-limiting embodiment of the present disclosure, the methanol fuel injection system includes a pressure regulation valve disposed downstream of the fuel pump. The pressure regulation valve is adapted to adjust a pressure of methanol fuel supplied to the fuel injectors.
[0048] In another non-limiting embodiment of the present disclosure, the methanol fuel injection system includes a fuel return line adapted to return the leaked methanol fuel from the pressure regulation valve to the methanol tank.
[0049] In another non-limiting embodiment of the present disclosure, the methanol fuel injection system comp includes rises a fuel rail that houses the fuel injectors and that is coupled with the fuel pump to receive and store the pressurized fuel to be supplied to the plurality of engine cylinders, via the fuel injectors.
[0050] In another non-limiting embodiment of the present disclosure, the exhaust aftertreatment system of the IC engine is a three-way catalytic converter type after treatment system disposed downstream of the exhaust manifold.
[0051] In another non-limiting embodiment of the present disclosure, the IC engine system includes muffler disposed downstream of the exhaust aftertreatment system to reduce the engine exhaust noise.
[0052] In another non-limiting embodiment of the present disclosure, the intake manifold receives the pressurized air from the turbocharger and supplies the pressurized air to the plurality of engine cylinders.
[0053] In another non-limiting embodiment of the present disclosure, the IC engine is a multi-cylinder four stroke engine.
[0054] In another non-limiting embodiment of the present disclosure, the IC engine has a compression ratio in the range of 10 to 12.
[0055] In another non-limiting embodiment of the present disclosure, the IC engine produces a power in a range of 120 to 160 horsepower (HP).
[0056] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
[0057] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in FIGS. 1 to 3 and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
[0058] Before describing detailed embodiments, it may be observed that the present disclosure is directed to an internal combustion engine system operable on 100 percent methanol fuel. It is to be noted that a person skilled in the art can be motivated from the present disclosure and modify the various constructions of the internal combustion engine system. However, such modifications should be construed within the scope of the present disclosure. Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
[0059] In the present disclosure, the term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or implementation of the present subject matter described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.
[0060] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover non-exclusive inclusions, such that a device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such device. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[0061] The terms like “at least one” and “one or more” may be used interchangeably or in combination throughout the description.
[0062] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the present disclosure.
[0063] Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible same numerals will be used to refer to the same or like parts.
[0064] Embodiments of the disclosure are described in the following paragraphs with reference to FIGS. 1 to 3. In FIGS. 1 to 3, the same element or elements which have same functions are indicated by the same reference signs.
[0065] Referring to FIG. 1, the present disclosure provides an internal combustion engine system (100) (hereinafter referred to as “the IC engine system (100)”) of a vehicle, such as bus, truck or other heavy-duty vehicles. The IC engine system (100) is adapted to run on 100% methanol fuel at high efficiency without the need for any other fuel blend or additive, and with power in the range of 120-160 HP that is sufficient to run buses/ trucks.
[0066] In accordance with the present disclosure, the IC engine system (100) includes an internal combustion (IC) engine (1) with a plurality of engine cylinders, each of which has a reciprocating piston therein, i.e., the IC engine (1) is a multi-cylinder engine. In an embodiment of the present disclosure, the IC engine (1) may include 4, 6 or 8 engine cylinders arranged either in-line with each other or ‘V-configuration’. Without deviating from the scope of the present disclosure, the plurality of engine cylinders of the IC engine (1) is adapted to work on four-stroke engine cycle. The IC engine system (100) has a compression ratio between 10 to 12 operating with 100% methanol fuel and produces a power in the range of 120 to 160 horsepower (HP). Also, the maximum speed of the IC engine (1) is 3000 revolutions per minute (rpm).
[0067] As depicted in FIG. 1, the IC engine system (100) includes the IC engine (1) with the plurality of engine cylinders, an intake manifold (9), an exhaust manifold (15), an engine air induction system, an exhaust aftertreatment system (17), a methanol fuel injection system, and an engine control unit (19). In an embodiment of the present disclosure, each engine cylinder of the plurality of engine cylinders has a reciprocating piston therein.
[0068] The intake manifold (9) is fluidly coupled to the plurality of engine cylinders, via a respective intake port of each engine cylinder of the plurality of engine cylinders of the IC engine (1). The intake manifold (9) is adapted to couple the engine air induction system with the plurality of engine cylinders such that the intake manifold (9) receives the pressurized, compressed and cooled air from the engine air induction system and supply the pressurized, compressed and cooled air to plurality of engine cylinders of the IC engine (1) for combustion purposes. The intake manifold (9) is further adapted to receive methanol fuel from the methanol fuel injection system. In accordance with the present disclosure, a combustible air-methanol fuel mixture is formed within the intake manifold (9) and said mixture is being supplied to each engine cylinder for combustion purposes.
[0069] Further, the exhaust manifold (15) is fluidly coupled to the plurality of engine cylinders, via a respective exhaust port of each engine cylinder of the plurality of engine cylinders of the IC engine (1). The exhaust manifold (15) is adapted to couple the exhaust ports of each engine cylinder of the IC engine (1) with the exhaust aftertreatment system (17), via a common exhaust pipe and a turbocharger (13) of the engine air induction system.
[0070] The IC engine system (100) further includes the engine air induction system that is coupled to the intake manifold (9) and adapted to supply air into the plurality of engine cylinders of the IC engine (1). In accordance with the present disclosure, the engine air induction system includes the turbocharger (13) to compress and increase a pressure of air supplied to the plurality of engine cylinders of the IC engine (1). In an embodiment, the turbocharger (13) is adapted to compress air and increase the pressure of air above the atmospheric pressure. Further, the turbocharger (13) is configured to be driven by exhaust gases of the IC engine (1).
[0071] Without deviating from the scope of the present disclosure, in an embodiment, the turbocharger (13) includes a rotary turbine driven by the exhaust gases of the IC engine (1). The rotary turbine is coupled to a rotary compressor that increases the pressure of air (i.e., the intake air) above the atmospheric pressure.
[0072] Further, the engine air induction system includes an intercooler (12) disposed downstream of the turbocharger (13). The intercooler (12) is adapted to reduce (i.e., bring down) the temperature of the compressed air exiting from the turbocharger (13), before the compressed air enters into the plurality of engine cylinders of the IC engine (1). The engine air induction system furthermore includes an air throttle (11) disposed downstream of the intercooler (12). The air throttle (11) is adapted to control an amount of air entering the intake manifold (9) so as to be supplied to the plurality of engine cylinders of the IC engine (1), during suction stroke of the plurality of engine cylinders of the IC engine (1).
[0073] Additionally, the engine air induction system includes an air filter (14) disposed upstream of the turbocharger (13). The air filter (14) is adapted to filter dust particles from the air entering the IC engine system (100).
[0074] Further, the IC engine system (100) includes the methanol fuel injection system that is coupled to the intake manifold (9) and adapted to supply methanol fuel to the plurality of engine cylinders of the IC engine (1). In accordance with the present disclosure, the methanol fuel injection system includes electronically controlled fuel injectors (10) for supplying methanol fuel into the intake manifold (9), and spark plugs (16) for igniting air-methanol fuel mixture in the plurality of engine cylinders of the IC engine (1). As shown in FIG. 1, the methanol fuel injection system includes a methanol tank (2) for storing and supplying methanol fuel to the fuel injectors (10) and the plurality of engine cylinders of the IC engine (1). In an example, the fuel injectors (10) are electronically controlled. The methanol tank (2) is made of a material that is suitable to contain methanol therein. In an exemplary embodiment, the methanol tank (2) is made of stainless steel. In other embodiment, the methanol tank (2) may be made of iron, coated with materials such as Teflon to avoid corrosion of the methanol tank (2) in long term use. Further, the methanol fuel injection system includes a filter (4) coupled to the methanol tank (2) via a fuel line (3). The filter (4) is adapted to filter particles of size 5 micrometers and above in methanol fuel. The fuel line (3) may also be made of material that is compatible with methanol, for example, stainless steel, or Teflon.
[0075] In accordance with the present disclosure, the methanol fuel injection system may include a fuel pump (5) disposed downstream of the methanol tank (2), for supplying methanol fuel to the plurality of fuel injectors (10) and the plurality of engine cylinders of the IC engine (1). In the embodiment shown in FIG. 1, the fuel pump (5) is disposed downstream of the filter (4), for supplying filtered methanol fuel to the plurality of fuel injectors (10) and the plurality of engine cylinders of the IC engine (1). Without deviating from the scope of the present disclosure, the parts of the fuel pump (5) may also be made of material that is compatible with methanol fuel.
[0076] Referring to FIG. 1, the methanol fuel injection system may include a pressure regulation valve (6) disposed downstream of the fuel pump (5). The pressure regulation valve (6) may be adapted to adjust a pressure of methanol fuel supplied to the plurality of fuel injectors (10). In an embodiment, the pressure regulation valve (6) may be made of stainless steel. The pressure regulation valve (6) may be configured to regulate and/ or maintain the pressure of methanol fuel in the range of 0 to 8 bar. Also, the methanol fuel injection system includes a fuel return line (7) adapted to return the leaked methanol fuel from the pressure regulation valve (6) to the methanol tank (2). Similar to the fuel line (3), the fuel return line (7) may be made of material that is compatible with methanol fuel, for example, stainless steel, or Teflon.
[0077] With reference to FIG. 1, the methanol fuel injection system includes a fuel rail (8). The fuel rail (8) houses the plurality of fuel injectors (10). The fuel rail (8) is adapted to be coupled to the fuel pump (5) to receive and store the pressurized methanol fuel to be supplied to the plurality of engine cylinders of the IC engine (1), via the fuel injectors (10).
[0078] In accordance with the present disclosure, the plurality of fuel injectors (10) of the methanol fuel injection system are electronically controlled fuel injectors and are adapted to be controlled by the engine control unit (19) (as discussed in the subsequent paragraphs). Without deviating from the scope of the present disclosure, a flow-rate specification of the plurality of fuel injectors (10) is calculated based on the estimated air trapped in each engine cylinder of the IC engine (1) and time available during the suction stroke of the IC engine (1) at its maximum speed. In an embodiment, one fuel injector (10) per engine cylinder is provided in the IC engine (1).
[0079] Further, each of the spark plugs (16) of the methanol fuel injection system is configured to produce a spark to ignite air-methanol fuel mixture in each engine cylinder of the IC engine (1) at a specific time according to an activation signal sent by the engine control unit (19) (as discussed in the subsequent paragraphs).
[0080] The IC engine system (100) furthermore includes the engine control unit (19) that is at least communicatively coupled to one or more sensors associated with components of the IC engine (1) and the methanol fuel injection system (particularly, the plurality of fuel injectors (10) and the spark plugs (16)). The engine control unit (19) is configured to receive, via sensors, operational parameters of the components of the IC engine (1). The engine control unit (19) is further configured to control at least one of an injection timing and an injection duration of the plurality of fuel injectors (10), and an ignition time of the spark plugs (16).
[0081] In an embodiment, based on the signals/ inputs received form the sensors of the IC engine (1), the engine control unit (19) sends signals to the plurality of fuel injectors (10) and the spark plugs (16) for controlling the injection timing and the injection duration of the plurality of fuel injectors (10) and the ignition time of the spark plugs (16). In an exemplary embodiment, the engine control unit (19) controls the injection timing and the injection duration of the plurality of fuel injectors (10), and the ignition time of the spark plugs (16) based on at least one of the estimated air trapped in each engine cylinder of the IC engine (1), IC engine speed, throttle positions, and time available during a suction stroke of each engine cylinder at maximum speed of the IC engine (1).
[0082] In accordance with the present disclosure, the engine control unit (19) receives various signals from different sensors mounted on the IC engine (1) and sends control signals to different actuators on the IC engine system (1). The control signals sent to the plurality of fuel injectors (10) and the spark plugs (16) are significant in order to decide the evaporation, optimal combustion of methanol fuel and finally the brake thermal efficiency of the IC engine system (1). Within the scope of the present disclosure, the injection duration is optimized to keep the overall equivalence ratio of the IC engine (1) at around 1 and injection timing is optimized to allow methanol fuel to evaporate and enter the respective engine cylinder. The injection timing becomes crucial in controlling the fuel quantity variations between the different engine cylinders of the IC engine (1) and resultant variations in the engine torque. Spark timing in part throttle conditions is optimized to obtain maximum brake torque and at wide open throttle to avoid knocking.
[0083] Further, the IC engine system (100) includes the exhaust aftertreatment system (17) that is coupled to the exhaust manifold (15) and adapted to treat the exhaust received from the plurality of engine cylinders of the IC engine (1). In an embodiment, the exhaust aftertreatment system (17) is a three-way catalytic converter type after treatment system disposed downstream of the exhaust manifold (15). Additionally, the IC engine system (100) includes muffler (18) disposed downstream of the exhaust aftertreatment system (17) to reduce the engine exhaust noise.
[0084] With reference to FIGS. 1 to 3, an operation on the IC engine system (100) of the present disclosure, and comparison of engine torque, power obtained by the IC engine system (100) (operable on methanol fuel), and brake thermal efficiency obtained by the IC engine system (100) (operable on methanol fuel) vis-à-vis those obtained by baseline CNG engines, are disclosed.
[0085] Reference to FIG. 1, methanol fuel from the methanol tank (2) is connected to a methanol compatible fuel pump (5) through the filter (4) using the fuel line (3). The fuel pump (5) may be run by power supply of 12 V (either battery or an electric adopter). An outlet of the fuel pump (5) is split into two parts, one of which is connected to the fuel rail (8) and the other is connected to the pressure regulation valve (6). An outlet of the pressure regulation valve (6) is connected back to the methanol tank (2). The fuel pump (5) is run continuously during IC engine (1) operation and the pressure regulation valve (6) is closed to increase the pressure of methanol fuel in the fuel rail (8). The pressure is observed in the fuel pressure monitor and the pressure regulation valve (6) is adjusted until the required pressure is achieved. The fuel rail (8) accommodates fuel inlets of the plurality of fuel injectors (10) which supplies methanol fuel into the IC engine (1) when an electric signal is given by the engine control unit (19). The flow-rate specification is calculated by using the quantity of air entering into the engine cylinders and time available for suction stroke at the maximum speed of the IC engine (1). In an exemplary embodiment, the plurality of fuel injectors (10) may have a flow rate of 970 cc/min at 3 bar of injection pressure.
[0086] Further, the engine control unit (19), which is an open engine control unit (ECU), allows changing many parameters of engine operation such as injection timings, injection duration, ignition timing as per the IC engine (1) speed and throttle position inputs. The engine control unit (19) collects data from the sensors mounted on the IC engine (1), such as boost pressure, temperature, lambda-sensor, etc., and sends control signals to the actuators of the IC engine (1), such as throttle valve, plurality of fuel injectors (10), and spark plugs (16). In an embodiment, fuel injection timing, fuel injection duration and ignition/ spark timing are the three major parameters which are optimized by calibration.
[0087] The injection duration at each operating point of the IC engine (1) is calibrated to maintain air-fuel equivalence ratio around 1. Fuel injection timing is an important parameter which ensures sufficient time for methanol fuel to evaporate and mix with intake air and form homogeneous mixture. Also, the injection timing affects the uniformity of methanol fuel supply between engine cylinders. Thus, injection timing is optimized in such a way that there is enough time for complete evaporation of methanol fuel and also to ensure equal distribution of methanol fuel to all the engine cylinders of the IC engine (1).
[0088] Further, if there is unequal distribution of methanol fuel between engine cylinders, fluctuations of torque are observed. The ignition/ spark timing is optimized to obtain maximum brake torque at part throttle points. At wide open throttle points, ignition/ spark timing is optimized to avoid knock.
[0089] Furthermore, the engine level tests are performed on an eddy current dynamometer to evaluate the engine performance. FIG. 2 shows a comparison of engine torque and power with ‘M100’ IC engine system (100) (that runs on methanol fuel) of the present disclosure in comparison to those of baseline CNG engine at wide open throttle points. It can be contemplated that the ‘M100’ IC engine system (100) of the present disclosure produces torque and power equal or better than those of baseline CNG configuration. A comparison of brake thermal efficiency, which is very important in description of energy efficiency of an energy conversion device, is illustrated in FIG. 3. It can be contemplated that the ‘M100’ IC engine system (100) facilitates improved brake thermal efficiencies as high as 38% which are around 3-5% higher than those of the baseline CNG engine.
[0090] Accordingly, the disclosed subject matter encompasses a multi-cylinder internal combustion engine (1) specifically configured for exclusive operation with pure (100%) methanol. The disclosure provides a IC engine (1) with an fuel injection system integrating a fuel filter (4), fuel pump (5), fuel pressure regulation valve (6), and plurality of fuel injectors (10), ensuring the effective and optimized delivery of methanol. Additionally, there is a meticulous optimization of injection quantity, timing, and ignition/spark timing, featuring an innovative port fuel injection strategy designed for the exclusive utilization of 100% methanol. The retrofitting of a custom-designed methanol port fuel injector system onto a production engine serves as a demonstration of adaptability. The present disclosure addresses the absence of turbocharged, spark-ignited, multi-cylinder truck/bus engines capable of operating solely on pure methanol and establishes new benchmarks in engine control, making a substantial contribution to the advancement of sustainable and high-performance heavy-duty vehicle propulsion.
[0091] In an example, the present invention involves the conversion of a large engine initially operated on Compressed Natural Gas (CNG) to operate efficiently on methanol, employing an external liquid fuel pump, fuel line pressure regulation, and liquid fuel injectors. This transformative adaptation enables the engine to achieve its rated maximum torque and power using methanol at approximately 50% throttle opening. This achievement is attributed to the enhanced volumetric efficiency resulting from the substitution of gaseous CNG with liquid methanol as the fuel source. Notably, the engine exhibits around a 3% increase in brake thermal efficiency when utilizing methanol. This improvement is accompanied by the maintenance of exhaust temperatures and peak firing pressures within permissible limits. The observation of higher efficiency with methanol underscores its viability as a superior alternative fuel for large engines.
[0092] During emission testing conducted under World Harmonized Transient Cycle (WHTC) conditions, methanol operation demonstrates a remarkable reduction of approximately 98% in NOx emissions compared to CNG operation. This signifies a substantial environmental advantage and aligns with emissions reduction goals.
[0093] The various embodiments of the present disclosure have been described above with reference to the accompanying drawings. The present disclosure is not limited to the illustrated embodiments; rather, these embodiments are intended to fully and completely disclose the subject matter of the disclosure to those skilled in this art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity.
[0094] Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “top”, “bottom” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the FIGS. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the FIGS. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
[0095] Herein, the terms “attached”, “connected”, “interconnected”, “contacting”, “mounted”, “coupled” and the like can mean either direct or indirect attachment or contact between elements, unless stated otherwise.
[0096] Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items.
[0097] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including” when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
[0098] While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

REFERENCE NUMERALS
PARTICULARS REFERRAL NUMERAL
Internal Combustion (IC) Engine System 100
Internal Combustion Engine 1
Methanol Tank 2
Fuel line 3
Filter 4
Fuel Pump 5
Pressure Regulation Valve 6
Fuel Return Line 7
Fuel Rail 8
Intake Manifold 9
Fuel Injectors 10
Air Throttle 11
Inter Cooler 12
Turbocharger 13
Air Filter 14
Exhaust Manifold 15
Spark Plug 16
Exhaust Aftertreatment System 17
Muffler 18
Engine Control Unit 19

EQUIVALENTS:
[0099] The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0100] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
[0101] Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
[0102] The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
[0103] Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
[0104] The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

ADVANTAGES OF INVENTION
[0105] The present disclosure provides an internal combustion engine system that operates on 100% methanol fuel, contributing to environmental sustainability by reducing carbon emissions and dependence on traditional fossil fuels.
[0106] The present disclosure provides an internal combustion engine that optimizes the utilization of methanol fuel, enhancing overall fuel efficiency.
[0107] The optimized combustion processes and careful control of injection parameters contribute to reduced wear and tear, potentially extending the overall lifespan of the internal combustion engine.
[0108] The present disclosure provides an economically viable engine considering manufacturing costs, maintenance requirements, and the potential for cost savings associated with the utilization of methanol fuel.
[0109] The inclusion of a muffler in the exhaust system contributes to the reduction of engine exhaust noise, providing a quieter and more pleasant driving experience.
[0110] The exhaust aftertreatment system, featuring a three-way catalytic converter, effectively treats exhaust gases, leading to reduced emissions and compliance with environmental regulations.
,CLAIMS:1. A fuel injection system for an internal combustion engine (1), comprising:
a methanol tank (2);
a pressure regulation valve (6) disposed downstream of a fuel pump (5) for adjusting a pressure of methanol fuel supplied to the fuel injectors;
a fuel rail (8) coupled to the fuel pump (5) for receiving and storing pressurized methanol fuel to be supplied to the plurality of engine cylinders, via the fuel injectors; and
a plurality of electronically controlled fuel injectors (10) housed in the fuel rail (8) and configured to supply methanol fuel into an intake manifold (9) of the internal combustion engine (1);
wherein the plurality of electronically controlled fuel injectors (10) are configured to be controlled by an engine control unit (19) based on operational parameters of the internal combustion engine, and
wherein the fuel injection system is configured to inject 100 percent methanol fuel.

2. The fuel injection system as claimed in claim 1, comprising a fuel return line (7) adapted to return leaked methanol fuel from the pressure regulation valve (6) to the methanol tank (2).

3. The fuel injection system as claimed in claim 1, wherein the plurality of fuel injectors (10) has an orifice size of about 500 µm and a flow rate of 970 cc/min at 3 bar of injection pressure.

4. The fuel injection system as claimed in claim 1, wherein plurality of electronically controlled fuel injectors (10) are liquid spray nozzles configured to obtain the required drop size distribution, thereby aid in the rapid evaporation of the droplets and preparation of a homogeneous air-fuel mixture.

5. The fuel injection system as claimed in claim 1, wherein the pressure regulation valve (6) is configured to maintain the pressure of methanol fuel in the fuel rail (8) in the range of 0 to 8 bar.

6. The fuel injection system as claimed in claim 1, wherein the fuel return line (7) is made of material compatible with methanol, comprising any or a combination of stainless steel and Teflon.

7. An internal combustion engine system (100) for vehicles, the system comprising:
an internal combustion (IC) engine (1) with a plurality of engine cylinders, each comprising a reciprocating piston;
an intake manifold (9) fluidly coupled to the plurality of engine cylinders via respective intake ports, configured to receive pressurized and cooled air from an engine air induction system, wherein an engine air induction system is coupled to the intake manifold (9), comprising a turbocharger (13) driven by exhaust gases of the IC engine, configured to compress and increase the pressure of air supplied to the plurality of engine cylinders;
an exhaust manifold (15) fluidly coupled to the plurality of engine cylinders via respective exhaust ports and an exhaust aftertreatment system (17) coupled to the exhaust manifold (15) for treating exhaust from the plurality of engine cylinders;
a fuel injection system coupled to the intake manifold (9), comprising plurality of fuel injectors (10) for supplying fuel into the intake manifold (9), and spark plugs (16) for igniting air-fuel mixture, wherein the fuel injection system is configured to inject 100% methanol fuel; and
an engine control unit (19) configured to receive operational parameters via sensors, and control injection timing and duration of the fuel injectors, and ignition timing of the spark plugs.

8. The system as claimed in claim 7, wherein the engine control unit (19) is configured to control injection timing and duration of the plurality of fuel injectors (10), and ignition timing of the spark plugs (16) based on one or more parameters pertaining to estimated air trapped in each engine cylinder, IC engine speed, throttle positions, and time available during a suction stroke of each engine cylinder at the maximum speed of the IC engine (1).

9. The system as claimed in claim 7, comprising an air filter disposed upstream of the turbocharger (13), and is adapted to filter dust particles from the air entering the IC engine (1).

10. The system as claimed in claim 7, wherein the IC engine (1) has a compression ratio in the range of 10 to 12.