System, method, and apparatus for fueling hydrogen combustion engines

Abstract

A fueling system is disclosed for a spark-ignited internal combustion engine that combusts hydrogen fuel. The fueling system includes at least two storage tanks that store hydrogen fuel under pressure. A controller apparatus can be configured so that one of the storage tanks is selected for fueling depending on the engine load and the pressure in each of the storage tanks in order to effectively utilize fuel storage and provide improved combustion performance.

Description

SYSTEM, METHOD, AND APPARATUS FOR FUELING HYDROGEN COMBUSTIONENGINESCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to, and the benefit of the filing date of, India Provisional Application No. 202441039870 filed on May 22, 2024, which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present application relates to apparatuses, methods, and systems for fueling internal combustion engines that combust hydrogen fuel.BACKGROUND

[0003] Internal combustion engines that combust hydrogen (H2) fuel provide near zero carbon emissions. High combustion temperatures associated with hydrogen fuel can result in high incylinder Nitrous Oxide (NOx) generation and cause the engine knocking tendency to increase during operation. As a result, the thermal efficiency for delivery of high power from the internal combustion engine can be negatively impacted.

[0004] In addition, direct injection systems that inject hydrogen fuel into the combustion chambers of the internal combustion engines are configured to operate at lower pressures (such as around 40-50 bar) to match the lower pressure operating range of the hydrogen fuel storage tanks. This maximizes fuel range available from the storage tanks and extends the fuel pressure availability of the storage tanks to generate the desired torque. However, direct injection of hydrogen fuel at lower pressures can result in lower thermal efficiency, higher NOx generation, and higher knocking tendency, especially at higher loads. Limiting operation of the direct injection system at a higher pressure to address these issues limits the quantity of hydrogen fuel in the storage tanks that can be used before a re-fill is necessary.

[0005] Therefore, existing approaches suffer from a number of disadvantages and shortcomings for using hydrogen fuel in direct injection spark-ignited internal combustion engines. There remains a significant need for the unique apparatuses, methods, and systems of the present disclosure.DISCLOSURE OF EXAMPLE EMBODIMENTS

[0006] For the purposes of clearly, concisely, and exactly describing example embodiments of the present disclosure, the manner, and process of making and using the same, and to enable the practice, making and use of the same, reference will now be made to certain example embodiments, including those illustrated in the figures, and specific language will be used to describe the same. It shall nevertheless be understood that no limitation of the scope of the invention is thereby created, and that the invention includes and protects such alterations, modifications, and further applications of the example embodiments as would occur to one skilled in the art.SUMMARY

[0007] Some embodiments include unique apparatuses for operating spark-ignited internal combustion engines using hydrogen fuel from hydrogen fuel storage tanks. Some embodiments include unique methods for operating spark-ignited internal combustion engines using hydrogen fuel from hydrogen fuel storage tanks. Some embodiments include unique systems for operating spark-ignited internal combustion engines using hydrogen fuel from hydrogen fuel storage tanks. Some embodiments determine and activate a combustion mode in response to pressure conditions of the hydrogen fuel storage tanks and demand on the internal combustion engine. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic diagram illustrating certain aspects of an example system including an internal combustion engine that combusts hydrogen fuel.

[0009] FIG. 2 illustrates certain aspects of a control process that can be implemented in a control apparatus for fueling the internal combustion engine of FIG. 1 with hydrogen fuel.

[0010] FIG. 3 is a diagram illustrating certain combustion modes for fueling the internal combustion engine of FIG. 1 with hydrogen fuel.

[0011] FIG. 4 is a flow diagram illustrating certain aspects of an embodiment of a method for fueling the internal combustion engine of FIG. 1 with hydrogen fuel.DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0012] With reference to FIG. 1, there is illustrated an example powertrain system 10 (also referred to herein as system 10) for a vehicle, genset, equipment, etc. Powertrain system 10 includes an engine 12 and a fueling system 14 with a plurality of hydrogen fuel storage tanks. In the illustrated embodiment, a first hydrogen fuel storage tank 36 and a second hydrogen fuel storage tank 38 are shown. Other embodiments contemplate more than two hydrogen fuel storage tanks are employed in series and / or in parallel. Reference herein to first and second hydrogen fuel storage tanks does not preclude additional hydrogen fuel storage tanks.

[0013] Fueling system 14 is adapted and configured to supply gaseous hydrogen fuel to engine 12 from a selected one of the hydrogen fuel storage tanks 36, 38 for combustion in one or more combustion chambers 15 of engine 12. In some embodiments, fueling system 14 may be additionally adapted and configured to supply one or more other fuels for combustion to engine 12 in combination with gaseous hydrogen. For example, engine 12 may run solely on hydrogen, on diesel and hydrogen, on natural gas and hydrogen, on propane and hydrogen, etc.

[0014] In an embodiment, system 10 includes an electronic control system (ECS) 80 with at least one electronic control unit (ECU) 82 configured to operate engine 12 with one or more operating parameters. The ECU 82 monitors one or more pressure conditions in fueling system 14 and a demand from engine 12 during operation of engine 12. The ECU 82 activates a combustion mode that is selected from a plurality of combustion modes in response to the engine demand and pressure conditions of the fueling system 14. In an embodiment, the ECU 82 selects one of the hydrogen fuel storage tanks 36, 38 to provide fueling based on the activated combustion mode and then controls fueling of engine 12 based on the selected storage tank 36, 38 and activated combustion mode.

[0015] In the illustrated embodiment, engine 12 comprises at least one cylinder 16 forming combustion chamber 15 that houses a piston 17 which reciprocates between bottom-dead-center (BDC) and top-dead-center (TDC) to generate mechanical power from the combustion of gaseous fuel supplied by fuel injector 18. Although only a single cylinder 16 is illustrated in FIG. 1, any number of cylinders 16, each with at least one fuel injector 18, is contemplated herein. System 10 may be provided in a number of forms including as a prime mover system (or component of a prime mover system) of a vehicle, a genset, other power-load system.

[0016] Fuel injector 18 is in fluid communication with the respective combustion chamber 15 of cylinder 16 of engine 12 and is structured to operate to inject gaseous hydrogen fuel. In the illustrated embodiment, fuel injector 18 is configured and provided as a direct fuel injector configured to inject fuel directly into respective combustion chamber 15 of cylinder 16. Other embodiments contemplate injector 18 is a port injector that injects hydrogen fuel directly into a port of intake manifold 20 leading to respective combustion chamber(s) 15 of cylinder(s) 16. Each cylinder 16 may also include one or more spark plugs 58, or other devices such as glow plugs, for spark ignition of the air-fuel mixture in the combustion chamber 15 of cylinder 16. It should be appreciated that engine 12 may include fewer or greater numbers of fuel inj ectors 18 and cylinders 16 than illustrated that are arranged and configured in a variety of manners. In an embodiment, the fuel injectors 18 and / or spark plugs 58 are controlled to change combustion processes in response to the activated combustion mode, as discussed further below.

[0017] In the illustrated embodiment, engine 12 of system 10 further includes an exhaust manifold 22 connected to receive an output from cylinder 16 and provide the output to exhaust system 24. Exhaust system 24 may include an aftertreatment system 26 and one or more other exhaust components, such as an exhaust conduit, a turbine of turbocharger 28, exhaust throttle, etc. Turbocharger 28 may include a turbine with a wastegate. In another embodiment, the turbine includes a variable inlet to control exhaust flow therethrough, such as a variable geometry turbine (VGT). In another embodiment, turbocharger 28 is omitted, and / or an exhaust throttle is provided.

[0018] Engine 12 of system 10 also includes an intake system 40. In an embodiment, turbocharger 28 includes a compressor in intake system 40 to receive the intake air flow for compression. In an embodiment, intake system 40 may include one or more of a charge air cooler (CAC) 42, an intake throttle 44, and an intake conduit 46 connecting these components to intake manifold 20. CAC 42 may include a CAC bypass and a CAC valve (not shown) to control the amount of intake air flow through CAC 42. Other embodiments contemplate other intake system components, and / or omission of one or more of the disclosed components. Still other embodiments contemplate an exhaust gas recirculation (EGR) system (not shown) to provide exhaust produced from one or more of cylinders 16 to intake system 40.

[0019] Fueling system 14 includes a fuel accumulator 32 connected to hydrogen fuel storage tanks 36, 38. Fueling system 14 also includes a common rail 34 connected between fuelaccumulator 32 and direct injector(s) 18. A first pressure regulator valve 60 connects first hydrogen fuel storage tank 36 to fuel accumulator 32. A second pressure regulator valve 62 connects second hydrogen fuel storage tank 38 to fuel accumulator 32. A third pressure regulator valve 64 connects fuel accumulator 32 to common rail 34. Each of the pressure regulator valves 60, 62, 64 and intake throttle 44 are connected to ECU 82 so that actuators of the pressure regulator valves 60, 62, 64 and intake throttle 44 can be commanded to move pressure regulator valves 60, 62, 64 and intake throttle 44 between open positions, closed positions, and one or more intermediate positions between the opened and closed positions.

[0020] Pressure regulator valves 60, 62, 64 of fueling system 14 are controlled during operation of engine 12 so that engine 12 operates with fueling from one of hydrogen fuel storage tanks 36, 38 based on the demand on engine 12 and pressure conditions of hydrogen fuel storage tanks 36, 38. Engine 12 may further include one or more pressure sensors 50, 52, 54, 56 configured to sense or detect one or more pressure conditions in fuel accumulator 32, common rail 34, first hydrogen fuel storage tank 36, and second hydrogen fuel storage tank 38, respectively. Pressure sensors 50, 52, 54, 56 can also be connected to ECU 82 so that ECU 82 can use the pressure conditions in the determination of the combustion mode to be activated and in the operation and positioning of pressure regulator valves 60, 62, 64.

[0021] Fuel accumulator 32 includes a volume that dampens the pressure peaks. This volume enables a smoother ramping up and down of the pressure conditions at common rail 34 during dynamic switching of the commanded rail pressure targets for common rail 34, fuel storage tank selections, and pressure regulator operations that depend on the selected combustion mode, as discussed further below. For example, the commanded pressure target for fuel accumulator 32 can be determined based on the selected combustion mode. Fuel accumulator 32 eliminates or reduces stability and sluggishness issues that may occur during switching the hydrogen fuel source between storage tanks 36, 38 in response to the selected combustion modes, leading to controlled combustion and stability.

[0022] In an embodiment, an accelerator pedal 30 is connected to ECU 82 to provide accelerator pedal position signals that are used to determine the demand or load on engine 12. One or more engine speed sensors or other sensors can also be used to provide information that determines the demand on engine 12. As used herein, “demand” should be construed broadly, andincludes a current demand and / or anticipated demand, a current engine load and / or anticipated engine load, an engine torque output, an anticipated engine torque output, etc.

[0023] System 10 further includes ECS 80 in electronic communication with engine 12 and configured to control one or more aspects of engine 12. ECS 80 includes at least one ECU 82 configured to execute operations of ECS 80 as described further herein and, in some embodiments, may include additional ECUs configured to execute operations of ECS 80 as described further herein.

[0024] ECS 80 and / or ECU 82 are configured to control pressure regulator valves 60, 62 to pressurize fuel accumulator 32 to a target pressure or desired pressure range with hydrogen fuel from a selected one of the hydrogen fuel storage tanks 36, 38. ECS 80 and / or ECU 82 are also configured to control pressure regulator valve 64 to maintain common rail 34 with pressurized hydrogen fuel at a commanded pressure or pressure range for fuel delivery to fuel inj ector 18. EC S 80 and / or ECU 82 are further configured to control the injection of fuel into engine 12 via the fuel injectors 18 and sparking timing with spark plugs 58. Accordingly, ECS 80 and / or ECU 82 may be in communication with the pressure regulator valves 60, 62, 64 and fuel injectors 18 and configured to command each fuel injector 18 on and off at prescribed times to inject fuel into the combustion chamber 15 of each cylinder 16 of engine 12 as desired for ignition with spark plugs 58 at a desire ignition timing.

[0025] ECS 80 and / or ECU 82 may be further structured to control other operating parameters of engine 12, which may include aspects of engine 12 that may be controlled with an actuator activated by ECS 80 and / or ECU 82. For example, ECS 80 and / or ECU 82 may be in communication with actuators and sensors for receiving and processing sensor input and transmitting actuator output signals. Actuators that control operating parameters of engine 12 may include, but are not limited to, fuel injectors 18, spark plugs 58, intake throttle 44, and pressure regulator valves 60, 62, 64. The sensors may include any suitable devices to monitor operating parameters and functions of the system 10. For example, the sensors may include one or more of pressure sensors 50, 52, 54, 56 in communication with one or more hydrogen fuel storage compartments or tanks. In at least one embodiment, system 10 may include one or more sensors 50, 52, 54, 56 in communication with the ECS 80 and / or ECU 82 structured to determine pressure conditions or characteristics of gases within with one or more hydrogen fuel storage compartmentsor tanks. In at least one embodiment of system 10, one or more sensors 50, 52, 54, 56 in communication with the ECS 80 and / or ECU 82 represents a virtual sensor that determines a pressure condition in the associated compartment based on an algorithm for predicting or determining a hydrogen pressure condition.

[0026] As will be appreciated by the description that follows, the techniques described herein relating to control of fueling of engine 12 can be implemented in ECS 80, which may include one or more controllers such as ECU 82 for controlling different aspects of the system 10. In one form, the ECS 80 comprises one or more ECU’s 82 such as an engine control unit or engine control module. The ECS 80 and / or ECU 82 may be comprised of digital circuitry, analog circuitry, or a hybrid combination of both of these types. Also, the ECS 80 and / or ECU 82 may be programmable, an integrated state machine, or a hybrid combination thereof. The ECS 80 and / or ECU 82 may include one or more Arithmetic Logic Units (ALUs), Central Processing Units (CPUs), memories, limiters, conditioners, fdters, format converters, or the like which are not shown to preserve clarity. In one form, the ECS 80 and / or ECU 82 are of a programmable variety that executes algorithms and processes data in accordance with operating logic that is defined by programming instructions (such as software or firmware). Alternatively, or additionally, operating logic for the ECS 80 and / or ECU 82 may be at least partially defined by hardwired logic or other hardware.

[0027] Referring to FIG. 2, an embodiment of a control process 200 for fueling engine 12 with hydrogen fuel using fueling system 14 illustrated. Process 200 can be implemented by, for example, ECS 80 and / or ECU 82 in order to control fueling of engine 12. Process 200 includes an input block 202 that receives and / or processes various operating parameter inputs from system 10. For example, the input parameters may include a pressure condition of first hydrogen fuel storage tank 36, a pressure condition of second hydrogen fuel storage tank 38 (and any additional hydrogen fuel storage tanks), a position of accelerator pedal 30, a speed of engine 12, and a rail pressure command for common rail 34. Other inputs are also contemplated and not precluded, such as a pressure condition for fuel accumulator 32 and common rail 34.

[0028] Control process 200 continues at a control strategy block 204 to determine a control strategy for fueling engine 12. The control strategy can include evaluating the input parameters that are received and / or determined at input block 202, and then selecting one of a plurality ofcombustion modes to implement for fueling engine 12 based on the evaluation of the input parameters. In an embodiment, the combustion modes from which to select include a low pressure direct injection (LPDI) combustion mode, a high pressure direct injection (HPDI) combustion mode, and an adaptive pressure direct injection (APDI) combustion mode. These combustion modes are discussed further below with respect to FIGs. 3-4.

[0029] Control process 200 continues at activation block 206 to activate the selected combustion mode from the determined control strategy. Activation of the selected combustion mode includes, for example, engaging one of first hydrogen fuel storage tank 36 and second hydrogen fuel storage tank 38 to be employed in supplying hydrogen fuel to fuel accumulator 32 and determining the rail pressure command of common rail 34 as a high pressure command or a low pressure command. The hydrogen fuel is then supplied to fuel accumulator 32 from the engaged one of the hydrogen fuel storage tanks 36, 38 to fuel accumulator 32, and from fuel accumulator 32 to common rail 34, and from common rail 34 to director injector(s) 18 using the activated one of the LPDI combustion mode, the HPDI combustion mode, and the APDI combustion mode. If the APDI combustion mode is activated, the rail pressure command for the common rail 34 is overridden to a rail pressure that is between the high pressure and low pressure commands, as discussed further below.

[0030] Control process 200 continues at engine calibration block 208. Engine calibration block 208 includes control of various engine operating parameters based on the activated combustion mode. The controlled engine operating parameters include, for example, a fuel injection pressure (high pressure, low pressure, or in between), a spark ignition timing, a fuel injection timing, fuel injection quantity, a position of intake throttle 44, and / or a glow plug timing. Other engine operating parameters may also be controlled based on the activated combustion mode and are not precluded.

[0031] With reference to FIG. 3, a diagram 300 provides an illustrative comparison of the LPDI combustion mode 302, the HPDI combustion mode 304, and the APDI combustion mode 306. The ability to switch between these combustion modes based on the demand for engine 12 and pressure conditions of first and second hydrogen fuel storage tanks 36, 38 provides for enhanced thermal efficiency, improved transient response, reduced engine knock, and extended vehicle range.

[0032] The LPDI combustion mode 302 is employed for engine demands less than a threshold demand. The threshold demand can be, for example, an associated engine demand or load that does not create, or is less likely to create, unfavorable knock conditions and NOx output when cylinders 16 of engine 12 are fueled with hydrogen fuel at a lower pressure condition at common rail 34. A low pressure condition for common rail 34 can be about 50 bar in an embodiment. In another embodiment, the low pressure condition ranges from about 10 bar to about 50 bar. Activation of LPDI combustion mode 302 can include selecting the hydrogen fuel storage tank 36, 38 having a pressure condition that supports the lower pressure fuel injection at lower engine loads that are less than the demand threshold, such as by having a pressure condition that is the minimum pressure condition of hydrogen fuel storage tank 36, 38.

[0033] The HPDI combustion mode 304 is employed for engine demands greater than the threshold demand. High pressure direction injection of hydrogen fuel from common rail 34 at higher engine demand or load conditions can prevent or reduce unfavorable knock conditions and NOx output as compared to fueling cylinders 16 of engine 12 with hydrogen fuel at a lower pressure condition at common rail 34. In an example embodiment, a high pressure condition for common rail 34 can be about 100 bar. Activation of HPDI combustion mode 304 can include selecting the hydrogen fuel storage tank 36, 38 having a pressure condition that supports high pressure fuel injection, such as by having a pressure condition that is the maximum pressure condition of hydrogen fuel storage tank 36, 38 and / or by having a pressure condition of 100 bar or more.

[0034] The APDI combustion mode 306 is employed for engine demands greater than the threshold demand when neither of the hydrogen fuel storage tank 36, 38 has a pressure condition that supports high pressure fuel injection. For example, if both hydrogen fuel storage tank 36, 38 are less than 100 bar, and the engine demand is greater than the demand threshold, then cylinders 16 of engine 12 are fueled with hydrogen fuel at a pressure that is between the low pressure (e.g. 50 bar) and high pressure (e.g. 100 bar) commands at common rail 34 by overriding the nominal rail pressure command. Activation of APDI combustion mode 306 can include selecting the hydrogen fuel storage tank 36, 38 having the highest pressure condition to minimize knock condition and NOx output to the greatest extent possible.

[0035] As shown in FIG. 3, hydrogen fuel is injected into the combustion chamber 15 using injector 18 after BDC 310 and before TDC 312 of the piston 17 for each of the LPDI combustion mode 302, HPDI combustion mode 304, and APDI combustion mode 306. However, the injection timing 322 can be closer to TDC for HPDI combustion mode 304 than the injection timing 320 for LPDI combustion mode 302. The injection timing 324 for APDI combustion mode 306 can be between the injection timing 320 for LPDI combustion mode 302 and injection timing 322 for HPDI combustion mode 304. In addition, the injection durations 330, 332, 334 and spark timing 340, 342, 344 for each of the respective LPDI combustion mode 302, HPDI combustion mode 304, and APDI combustion mode 306 can also vary between the combustion modes.

[0036] Referring to FIG. 4, there is illustrated a flow diagram of a procedure or method 400 for fueling engine 12 with fueling system 14 and an electronic control system (e.g., ECS 80 or another electronic control system), in operative communication with a fueling system 14. Method 400 may be implemented in and performed by one or more components of an electronic control system such as one or more electronic control units (e.g., ECU 82 and / or other electronic control units) and / or by other electronic control system components.

[0037] Method 400 begins at conditional 402, which determines if the pressure conditions of one or more hydrogen fuel storage tanks 36, 38 are above an empty tank threshold. If conditional 402 is NO, process 400 ends at 404 and a signal is output indicating one or both of hydrogen fuel storage tanks 36, 38 is empty.

[0038] If conditional 402 is YES, process 400 continues at START operation 406 in order to determine and activate one of the combustion modes. Conditional 408 follows START operation 406, and method 400 determines if the demand or load on engine 12 is greater than a demand threshold at conditional 408. The demand can be determined from, for example, the position of accelerator pedal 30, engine speed, etc. The demand threshold can indicate a division between a high demand on engine 12 and a low demand on engine 12. For example, the demand threshold can be a percentage of the maximum torque capability or capacity of engine 12, such as 50% of the maximum torque capability or capacity or some other percentage. Any percentage or range of percentages of the maximum capability of engine 12 can be selected in order to set the demand threshold. In addition, the demand threshold can be dynamic and vary based on one or more operating parameters of system 10, environmental factors, fuel pressure conditions, etc.

[0039] If conditional 408 is NO, a low demand or load condition is indicated, and process 400 continues at conditional 410 to determine if a minimum pressure condition between hydrogen fuel storage tanks 36, 38 is greater than a commanded rail pressure for the LPDI combustion mode. For example, conditional 410 evaluates if the hydrogen fuel storage tank 36, 38 having the minimum pressure has a pressure greater than 50 bar. If conditional 410 is YES, process 400 continues at operation 412 to activate the LPDI combustion mode and engage the hydrogen fuel storage tank 36, 38 with the minimum pressure. Process 400 then continues at operation 414 to determine an optimum pressure for fuel accumulator 32 and control the pressure regulator valves to obtain the optimum pressure at fuel accumulator 32 and the commanded low pressure at common rail 34 to provide fuel to fuel injectors 18.

[0040] If conditional 410 is NO, process 400 continues at conditional 416 to determine if the maximum pressure between hydrogen fuel storage tanks 36, 38 is greater than the LPDI combustion mode commanded low pressure. If conditional 416 is NO, process 400 continues at operation 418 to operate engine 12 in a derate mode due to neither of hydrogen fuel storage tank 36, 38 being capable of supplying hydrogen fuel at the LPDI combustion mode commanded low pressure.

[0041] If conditional 416 is YES, process 400 continues at operation 420 to select and activate the LPDI combustion mode and engage the hydrogen fuel storage tank 36, 38 that has the maximum fuel pressure condition. Process 400 then continues at operation 422 to determine an optimum pressure for fuel accumulator 32 and control the pressure regulator valves to obtain the optimum pressure at fuel accumulator 32 and the commanded low pressure at common rail 34.

[0042] If conditional 408 is YES, engine 12 is operating in a high demand or load condition. Process 400 continues at conditional 424 to determine if the maximum pressure condition of hydrogen fuel storage tank 36, 38 is greater than a HPDI combustion mode pressure threshold. For example, conditional 424 determines if the storage tank 36, 38 having the maximum pressure has a pressure condition greater than the commanded rail pressure for the HPDI combustion mode, such as 100 bar. If conditional 424 is YES, process 400 continues at operation 426 to select and activate the HPDI combustion mode and engage the hydrogen fuel storage tank 36, 38 that has the maximum fuel pressure condition. Process 400 then continues at operation 428 to determine anoptimum pressure for fuel accumulator 32 and control the pressure regulator valves to obtain the optimum pressure at fuel accumulator 32 and the commanded high pressure at common rail 34.

[0043] If conditional 424 if NO, process 400 continues at operation 430 to select and activate the APDI combustion mode and engage the hydrogen fuel storage tank 36, 38 that has the maximum or highest fuel pressure condition. Process 400 then continues at operation 432 to determine an optimum pressure for fuel accumulator 32 and control the pressure regulator valves to obtain the optimum pressure at fuel accumulator 32. At operation 434, the commanded rail pressure at common rail 34 in the APDI combustion mode is between the low pressure command and the high pressure command by overriding the nominal high and low pressure commands.

[0044] As shown by this detailed description, the present disclosure contemplates multiple and various embodiments, including, without limitation, the following example embodiments. In an embodiment, a method of operating a spark-ignited internal combustion engine that combusts hydrogen fuel includes: determining a first pressure condition of a first hydrogen fuel storage tank, a second pressure condition of a second hydrogen fuel storage tank, and a demand on the internal combustion engine; activating a combustion mode for operation of the internal combustion engine based on the first and second pressure conditions of the first and second hydrogen fuel storage tanks and the demand on the internal combustion engine, wherein the activated combustion mode includes a selection of one of the first and second hydrogen fuel storage tanks; and fueling the internal combustion engine with hydrogen fuel from the selected one of the first and second hydrogen fuel storage tanks based on the activated combustion mode.

[0045] In an embodiment, the activated combustion mode is one of a low pressure direct injection combustion mode, a high pressure direct injection combustion mode, and an adaptive pressure direct injection combustion mode.

[0046] In yet a further embodiment, the low pressure direct injection combustion mode is selected in response to the demand being less than a demand threshold and at least one of the first and second pressure conditions being greater than a low pressure threshold for the first and second hydrogen fuel storage tanks, the high pressure direct injection combustion mode is selected in response to the demand being greater than the demand threshold and at least one of the first and second pressure conditions being greater than a high pressure threshold for the first and second hydrogen fuel storage tanks, and the adaptive pressure direct injection combustion mode isselected in response to the demand being greater than the demand threshold and both of the first and second pressure conditions being less than the high pressure threshold for the first and second hydrogen fuel storage tanks.

[0047] In yet a further embodiment, a derate mode is selected in response to each of the first and second pressure conditions being less than the low pressure threshold for the first and second hydrogen fuel storage tanks.

[0048] In yet a further embodiment, the low pressure direct injection combustion mode operates to fuel the internal combustion engine at a fuel injection pressure based on the low pressure threshold, the high pressure direct injection combustion mode operates to fuel the internal combustion engine at a fuel injection pressure based on the high pressure threshold, and the adaptive pressure direct injection combustion mode operates to fuel the internal combustion engine at a fuel injection pressure that is between the low pressure threshold and the high pressure threshold.

[0049] In a further embodiment, fueling the internal combustion engine with hydrogen fuel from the selected one of the first and second hydrogen fuel storage tanks based on the activated combustion mode includes controlling a fuel injection pressure, spark ignition timing, injection timing, and injection duration based on the activated combustion mode.

[0050] In yet a further embodiment, the injection timing in the high pressure direct injection combustion mode is later than the injection timing in the low pressure direct injection combustion mode.

[0051] In yet a further embodiment, the injection timing in the adaptive pressure direct injection combustion mode is between the injection timing in the high pressure direct injection combustion mode and the injection timing in the low pressure direct injection combustion mode.

[0052] In yet a further embodiment, the demand is determined at least in part based on an accelerator pedal position and a speed of the internal combustion engine.

[0053] In yet a further embodiment, the first and second hydrogen fuel storage tanks are each controllably connected to a fuel accumulator that is configured to store hydrogen fuel. The fuel accumulator is controllably connected to a common rail that is downstream of the fuel accumulatorThe common rail is configured to distribute hydrogen fuel to one or more direct injectors of the internal combustion engine.

[0054] According to another aspect of the present disclosure, a spark-ignited internal combustion engine that combusts hydrogen fuel is provided. The internal combustion engine incudes at least one combustion chamber for receiving an intake flow, at least one fuel injector for injecting hydrogen fuel into the at least one combustion chamber for combustion of the hydrogen fuel with the intake flow, a plurality of hydrogen fuel storage tanks including at least a first hydrogen fuel storage tank and a second hydrogen fuel storage tank that separately store hydrogen fuel, a fuel accumulator separately connected to each of the first and second hydrogen fuel storage tanks so that hydrogen fuel can be received into the fuel accumulator from a selected one of the first and second hydrogen fuel tanks, and a common rail connected to the fuel accumulator and the at least one fuel injector, the common rail distributing fuel from the fuel accumulator to the at least one fuel injector.

[0055] In an embodiment, the internal combustion engine includes a first pressure regulator valve connecting the first hydrogen fuel storage tank and the fuel accumulator, a second pressure regulator valve connecting the second hydrogen fuel storage tank and the fuel accumulator, and a third pressure regulator valve connecting the fuel accumulator and the common rail.

[0056] In a further embodiment, the internal combustion engine includes a first pressure sensor operable to sense a pressure condition in the fuel accumulator, a second pressure sensor operable to sense a pressure condition in the common rail, a third pressure sensor operable to sense a pressure condition in the first hydrogen fuel storage tank, and a fourth pressure sensor operable to sense a pressure condition in the second hydrogen fuel storage tank.

[0057] In yet a further embodiment, the internal combustion engine includes an engine control unit configured to control operation of the first pressure regulator valve, the second pressure regulator valve, and the third pressure regulator valve in response to a demand from the internal combustion engine, a first pressure condition of the first hydrogen fuel storage tank, and a second pressure condition of the second hydrogen fuel storage tank.

[0058] In yet a further embodiment, the engine control unit is configured to activate a combustion mode for operation of the internal combustion engine based on the first and secondpressure conditions of the first and second hydrogen fuel storage tanks and the demand on the internal combustion engine.

[0059] In yet a further embodiment, the engine control unit is configured to select one of the first and second hydrogen fuel storage tanks based on the activated combustion mode provide fuel to the fuel accumulator from the selected one of the first and second hydrogen fuel storage tanks.

[0060] In yet a further embodiment, the activated combustion mode is one of a low pressure direct injection combustion mode, a high pressure direct injection combustion mode, and an adaptive pressure direct injection combustion mode.

[0061] In yet a further embodiment, the engine control unit is configured to adjust an injection timing of the hydrogen fuel from the at least one fuel injector based on the activated one of the low pressure direct injection combustion mode, the high pressure direct injection combustion mode, and the adaptive pressure direct injection combustion mode.

[0062] According to another aspect of the disclosure, an apparatus is configured to control fueling of a spark-ignited internal combustion engine that combusts hydrogen. The apparatus includes an electronic control unit having a processor with a memory. The memory includes instructions encoded thereon that cause the processor to: determine a first pressure condition of a first hydrogen fuel storage tank, a second pressure condition of a second hydrogen fuel storage tank, and a demand on the internal combustion engine; activate a combustion mode for operation of the internal combustion engine based on the first and second pressure conditions of the first and second hydrogen fuel storage tanks and the demand on the internal combustion engine, wherein the activated combustion mode includes a selection of one of the first and second hydrogen fuel storage tanks; and fuel the internal combustion engine with hydrogen fuel from the selected one of the first and second hydrogen fuel storage tanks based on the activated combustion mode.

[0063] In an embodiment, the instructions encoded in the processor of the engine control unit cause the processor to: select a low pressure direct injection combustion mode in response to the demand being less than a demand threshold and at least one of the first and second pressure conditions being greater than a low pressure threshold for the first and second hydrogen fuel storage tanks; select a high pressure direct injection combustion mode in response to the demand being greater than the demand threshold and at least one of the first and second pressure conditions being greater than a high pressure threshold for the first and second hydrogen fuel storage tanks;and select an adaptive pressure direct injection combustion mode in response to the demand being greater than the demand threshold and both of the first and second pressure conditions being less than the high pressure threshold for the first and second hydrogen fuel storage tanks.

[0064] It shall be appreciated that terms such as “a non-transitory memory,” “a non-transitory memory medium,” and “a non-transitory memory device” refer to a number of types of devices and storage mediums which may be configured to store information, such as data or instructions, readable or executable by a processor or other components of a computer system and that such terms include and encompass a single or unitary device or medium storing such information, multiple devices or media across or among which respective portions of such information are stored, and multiple devices or media across or among which multiple copies of such information are stored.

[0065] It shall be appreciated that terms such as “determine,” “determined,” “determining” and the like when utilized in connection with a control method or process, an electronic control system or controller, electronic controls, or components or operations of the foregoing refer inclusively to a number of acts, configurations, devices, operations, and techniques including, without limitation, calculation or computation of a parameter or value, obtaining a parameter or value from a lookup table or using a lookup operation, receiving parameters or values from a datalink or network communication, receiving an electronic signal (e. ., a voltage, frequency, current, or pulse-width modulation (PWM) signal) indicative of the parameter or value, receiving output of a sensor indicative of the parameter or value, receiving other outputs or inputs indicative of the parameter or value, reading the parameter or value from a memory location on a computer- readable medium, receiving the parameter or value as a run-time parameter, and / or by receiving a parameter or value by which the interpreted parameter can be calculated, and / or by referencing a default value that is interpreted to be the parameter value.

[0066] While example embodiments of the disclosure have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain example embodiments have been shown and described and that all changes and modifications that come within the spirit of the claimed inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicates that the feature so described may be more desirable, it nonetheless may not be necessaryand embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and / or “a portion” is used the item can include a portion and / or the entire item unless specifically stated to the contrary.

Claims

1. WHAT IS CLAIMED IS:

1. A method of operating a spark-ignited internal combustion engine that combusts hydrogen fuel, the method comprising: determining a first pressure condition of a first hydrogen fuel storage tank, a second pressure condition of a second hydrogen fuel storage tank, and a demand on the internal combustion engine; activating a combustion mode for operation of the internal combustion engine based on the first and second pressure conditions of the first and second hydrogen fuel storage tanks and the demand on the internal combustion engine, wherein the activated combustion mode includes a selection of one of the first and second hydrogen fuel storage tanks; and fueling the internal combustion engine with hydrogen fuel from the selected one of the first and second hydrogen fuel storage tanks based on the activated combustion mode.

2. The method according to claim 1, wherein the activated combustion mode is one of a low pressure direct injection combustion mode, a high pressure direct injection combustion mode, and an adaptive pressure direct injection combustion mode.

3. The method according to claim 2, wherein: the low pressure direct injection combustion mode is selected in response to the demand being less than a demand threshold and at least one of the first and second pressure conditions being greater than a low pressure threshold for the first and second hydrogen fuel storage tanks; the high pressure direct injection combustion mode is selected in response to the demand being greater than the demand threshold and at least one of the first and second pressure conditions being greater than a high pressure threshold for the first and second hydrogen fuel storage tanks; and the adaptive pressure direct injection combustion mode is selected in response to the demand being greater than the demand threshold and both of the first and second pressure conditions being less than the high pressure threshold for the first and second hydrogen fuel storage tanks.

4. The method according to claim 3, wherein a derate mode is selected in response to each of the first and second pressure conditions being less than the low pressure threshold for the first and second hydrogen fuel storage tanks.

5. The method according to claim 3, wherein: the low pressure direct injection combustion mode operates to fuel the internal combustion engine at a fuel injection pressure based on the low pressure threshold; the high pressure direct injection combustion mode operates to fuel the internal combustion engine at a fuel injection pressure based on the high pressure threshold; and the adaptive pressure direct injection combustion mode operates to fuel the internal combustion engine at a fuel injection pressure that is between the low pressure threshold and the high pressure threshold.

6. The method according to claim 2, wherein fueling the internal combustion engine with hydrogen fuel from the selected one of the first and second hydrogen fuel storage tanks based on the activated combustion mode includes controlling a fuel injection pressure, spark ignition timing, injection timing, and injection duration based on the activated combustion mode.

7. The method according to claim 6, wherein the injection timing in the high pressure direct injection combustion mode is later than the injection timing in the low pressure direct injection combustion mode.

8. The method according to claim 7, wherein the injection timing in the adaptive pressure direct injection combustion mode is between the injection timing in the high pressure direct injection combustion mode and the injection timing in the low pressure direct injection combustion mode.

9. The method according to claim 1, wherein the demand is determined at least in part based on an accelerator pedal position and a speed of the internal combustion engine.

10. The method according to claim 1, wherein:the first and second hydrogen fuel storage tanks are each controllably connected to a fuel accumulator that is configured to store hydrogen fuel; and the fuel accumulator is controllably connected to a common rail that is downstream of the fuel accumulator, the common rail being configured to distribute hydrogen fuel to one or more direct injectors of the internal combustion engine.

11. A spark-ignited internal combustion engine that combusts hydrogen fuel, the internal combustion engine comprising: at least one combustion chamber for receiving an intake flow; at least one fuel injector for injecting hydrogen fuel into the at least one combustion chamber for combustion of the hydrogen fuel with the intake flow; a plurality of hydrogen fuel storage tanks including at least a first hydrogen fuel storage tank and a second hydrogen fuel storage tank that separately store hydrogen fuel; a fuel accumulator separately connected to each of the first and second hydrogen fuel storage tanks so that hydrogen fuel can be received into the fuel accumulator from a selected one of the first and second hydrogen fuel tanks; and a common rail connected to the fuel accumulator and the at least one fuel injector, the common rail distributing fuel from the fuel accumulator to the at least one fuel injector.

12. The internal combustion engine according to claim 11, comprising: a first pressure regulator valve connecting the first hydrogen fuel storage tank and the fuel accumulator; a second pressure regulator valve connecting the second hydrogen fuel storage tank and the fuel accumulator; and a third pressure regulator valve connecting the fuel accumulator and the common rail.

13. The internal combustion engine according to claim 12, comprising: a first pressure sensor operable to sense a pressure condition in the fuel accumulator; a second pressure sensor operable to sense a pressure condition in the common rail; a third pressure sensor operable to sense a pressure condition in the first hydrogen fuel storage tank; anda fourth pressure sensor operable to sense a pressure condition in the second hydrogen fuel storage tank.

14. The internal combustion engine according to claim 13, comprising an engine control unit configured to control operation of the first pressure regulator valve, the second pressure regulator valve, and the third pressure regulator valve in response to a demand from the internal combustion engine, a first pressure condition of the first hydrogen fuel storage tank, and a second pressure condition of the second hydrogen fuel storage tank.

15. The internal combustion engine according to claim 14, wherein the engine control unit is configured to activate a combustion mode for operation of the internal combustion engine based on the first and second pressure conditions of the first and second hydrogen fuel storage tanks and the demand on the internal combustion engine.

16. The internal combustion engine according to claim 15, wherein the engine control unit is configured to select one of the first and second hydrogen fuel storage tanks based on the activated combustion mode provide fuel to the fuel accumulator from the selected one of the first and second hydrogen fuel storage tanks.

17. The internal combustion engine according to claim 15, wherein the activated combustion mode is one of a low pressure direct injection combustion mode, a high pressure direct injection combustion mode, and an adaptive pressure direct injection combustion mode.

18. The internal combustion engine according to claim 17, wherein the engine control unit is configured to adjust an injection timing of the hydrogen fuel from the at least one fuel injector based on the activated one of the low pressure direct injection combustion mode, the high pressure direct injection combustion mode, and the adaptive pressure direct injection combustion mode.

19. An apparatus configured to control fueling of a spark-ignited internal combustion engine that combusts hydrogen, the apparatus including an electronic control unit having a processor with a memory, the memory including instructions encoded thereon that cause the processor to: determine a first pressure condition of a first hydrogen fuel storage tank, a second pressure condition of a second hydrogen fuel storage tank, and a demand on the internal combustion engine; activate a combustion mode for operation of the internal combustion engine based on the first and second pressure conditions of the first and second hydrogen fuel storage tanks and the demand on the internal combustion engine, wherein the activated combustion mode includes a selection of one of the first and second hydrogen fuel storage tanks; and fuel the internal combustion engine with hydrogen fuel from the selected one of the first and second hydrogen fuel storage tanks based on the activated combustion mode.

20. The apparatus according to claim 19, wherein the instructions encoded in the processor of the engine control unit cause the processor to: select a low pressure direct injection combustion mode in response to the demand being less than a demand threshold and at least one of the first and second pressure conditions being greater than a low pressure threshold for the first and second hydrogen fuel storage tanks; select a high pressure direct injection combustion mode in response to the demand being greater than the demand threshold and at least one of the first and second pressure conditions being greater than a high pressure threshold for the first and second hydrogen fuel storage tanks; and select an adaptive pressure direct injection combustion mode in response to the demand being greater than the demand threshold and both of the first and second pressure conditions being less than the high pressure threshold for the first and second hydrogen fuel storage tanks.

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