ENGINE CONTROL SYSTEM

Abstract

P603287PC00 18 Abstract An engine start system for a hydrogen fuelled internal combustion engine, the system comprising a controller; at least one fuel ignition device in communication with the controller; and a hydrogen fuel delivery system in communication with the controller; wherein the system is configured such that upon receipt of an engine start command, the controller is configured to instruct sparking of the fuel ignition device without instructing the supply of fuel to commence and is configured to monitor an output of the fuel ignition device for a signal indicative of the generation of a spark. [Figure 1]

Description

1 / 21 ENGINE CONTROL SYSTEM FIELD

[0001] These teachings relate to an engine control system. In particular, these teachings relate to an engine starting system for a hydrogen-powered internal combustion engine. Furthermore, these teachings relate to an engine shutdown system and a method of operation or starting and / or shutdown of a hydrogen-powered internal combustion engine. BACKGROUND

[0002] In modern internal combustion (IC) engines, fuel is injected directly or indirectly into each combustion chamber by a fuel injector. Upstream of the fuel injector is a common fuel rail that distributes fuel to each injector under pressure.

[0003] In order to reduce emissions from internal combustion engines, as well as potentially reduce greenhouse gases, hydrogen is being proposed as an alternative to diesel or gasoline as fuel for these engines.

[0004] Due to the intrinsic properties of hydrogen, it has been found that, under certain circumstances, it leaks over time from the fuel rail, through the injectors, into the intake system and / or cylinders of internal combustion engines. At the operating pressures within the common fuel rail and given its compressible nature, a large volume of hydrogen can therefore remain within these areas of the engine.

[0005] When the engine is subsequently restarted, there is therefore a risk that this hydrogen will cause a thermal or flashback event, which can damage engine components, which is clearly undesirable. There is also a risk of hydrogen escaping into the environment, which is also Petition 870250081175, dated 10 / 09 / 2025, pages 50 / 102 2 / 21 undesirable because, in its non-combustible form, it is itself a greenhouse gas.

[0006] Furthermore, the main product of hydrogen combustion in an internal combustion engine is water. There is believed to be a high risk of water fouling in the spark plugs used in hydrogen-fueled internal combustion engines. This can prevent hydrogen combustion in one or more cylinders of an engine, which can prevent the engine from functioning fully or cause it to function with only a reduced number of cylinders. In the latter case, this can result in undesirable hydrogen emissions, compromised engine power, and / or damage to engine components.

[0007] These teachings seek to overcome, or at least mitigate, the problems of the previous technique. SUMMARY

[0008] The present invention provides an engine starting system for a hydrogen-powered internal combustion engine, a hydrogen-powered internal combustion engine and a method for starting a hydrogen-powered internal combustion engine according to the appended claims.

[0009] A first aspect of the teachings provides an engine starting system for a hydrogen-fueled internal combustion engine. The system may comprise a controller; at least one fuel ignition device in communication with the controller and / or a hydrogen fuel supply system in communication with the controller. The system may be configured so that, upon receiving an engine start command, the controller is configured to instruct the ignition of the fuel ignition device without instructing the start of the fuel supply and may also be configured to monitor an output from the fuel ignition device for a signal indicating the generation of a spark. Petition 870250081175, dated 10 / 09 / 2025, pp. 51 / 102 3 / 21

[00010] Advantageously, this arrangement prevents unburned hydrogen from being expelled from the engine due to the absence of a spark in the engine cylinder to cause combustion. Venting unburned hydrogen is undesirable from a safety and environmental standpoint.

[00011] Optionally, upon detecting a spark, the controller is configured to instruct the fuel supply for combustion in the engine.

[00012] Advantageously, once a spark is detected, it is then appropriate to supply the fuel, since this will be burned instead of being expelled into the atmosphere.

[00013] Optionally, the controller is additionally configured to determine whether the internal combustion engine's fuel supply system is free of excess hydrogen before instructing the ignition of at least one fuel ignition device.

[00014] Advantageously, this ensures that the controller can prevent ignition if there is a risk that the hydrogen already present in the engine will be burned uncontrollably, which could damage the engine.

[00015] Optionally, the controller is additionally configured to instruct a drying operation of at least one fuel ignition device when it determines that the ignition of the fuel ignition device was unsuccessful.

[00016] Advantageously, this can allow the engine to function normally without requiring any specific maintenance operation.

[00017] Optionally, during the fuel ignition device drying operation, the controller signals the ignition of each fuel ignition device(s) that has been determined to be wet. Petition 870250081175, dated 10 / 09 / 2025, pp. 52 / 102 4 / 21

[00018] Advantageously, the ignition operation promotes the drying of the ignition devices by the flow of a current through them.

[00019] Ignition can typically be performed multiple times. In some systems, ignition may only be possible in combination with engine starting, according to a normal engine cycle, but in other systems it may be performed independently of starting and therefore may be possible more frequently.

[00020] Optionally, the fuel ignition device drying operation comprises starting the engine without fuel supply.

[00021] Advantageously, starting the engine promotes an airflow through the fuel ignition device, promoting its drying.

[00022] Optionally, during the drying operation, the controller is configured to monitor the output of the fuel ignition device for a signal indicating the generation of a spark.

[00023] This signal indicates the success of the drying operation.

[00024] Optionally, if a signal indicating the generation of a spark is detected, the controller is configured to instruct the cessation of the drying operation and to instruct the supply of fuel to an engine cylinder corresponding to the fuel ignition device.

[00025] Advantageously, this allows minimizing the delay in starting the engine if the fuel ignition device is dry.

[00026] Optionally, the controller is configured after instructing the fuel supply to monitor fuel combustion in the cylinder. Petition 870250081175, dated 10 / 09 / 2025, pp. 53 / 102 5 / 21

[00027] Although a dry fuel ignition device will likely result in combustion, it is advantageous to verify that combustion actually occurs, to prevent unburned hydrogen from being expelled into the engine environment.

[00028] Optionally, the controller is configured to instruct the interruption of the fuel supply to the cylinder and to instruct the generation of a spark for that cylinder if no combustion is detected.

[00029] Advantageously, this allows another opportunity for drying to occur, in particular, if other cylinders are burning fuel, the engine can run with less than all the cylinders and those that are not running can have another opportunity to dry.

[00030] Optionally, the controller is configured to instruct the fuel supply to the cylinder in case a spark is detected for that cylinder.

[00031] Advantageously, this allows normal engine operation to be achieved continuously, once the relevant fuel ignition device is dry.

[00032] Optionally, the controller is configured to determine if the engine is free of excess hydrogen, confirming whether a previous normal engine shutdown procedure has been completed.

[00033] It is advantageous for the hydrogen to be removed before the engine is shut down, so as not to delay the next engine start.

[00034] Optionally, the controller is configured to instruct a hydrogen purge operation in the event that the internal combustion engine is determined not to be free of excess hydrogen.

[00035] If there is a possibility of excess hydrogen, it is desirable, for safety reasons, that it be Petition 870250081175, dated 10 / 09 / 2025, pp. 54 / 102 6^21 is eliminated before testing the ignition, as otherwise, an event may occur that could produce negative effects.

[00036] Optionally, the controller is configured to instruct the engine to start without instructing the ignition of the fuel ignition device, in order to purge hydrogen from the engine.

[00037] Advantageously, this is an effective way to eliminate hydrogen without the need for additional hardware in the engine.

[00038] Optionally, the controller is additionally configured to instruct the hydrogen fuel supply system not to supply fuel during the purge operation.

[00039] To minimize the volume of hydrogen to be disposed of, it is desirable not to purge any hydrogen that remains upstream of the hydrogen fuel supply system.

[00040] Optionally, the controller is configured to instruct the purge operation for a predetermined time or for a predetermined number of engine revolutions.

[00041] Advantageously, these are effective methods for determining when a finite volume of hydrogen in the engine will be purged.

[00042] Optionally, at least one fuel ignition device comprises an ignition coil and a spark plug.

[00043] Optionally, the hydrogen fuel supply system comprises at least one fuel injector optionally in fluid flow communication with a common fuel rail.

[00044] Optionally, the engine comprises a plurality of cylinders.

[00045] Optionally, the controller is configured to instruct the interruption of the drying operation only in the event of Petition 870250081175, dated 10 / 09 / 2025, pages 55 / 102 7 / 21 an indicative signal of the generation of a spark to be detected in the fuel ignition devices corresponding to each of the plurality of cylinders.

[00046] It is desirable that all fuel ignition devices be completely dry for a successful engine start.

[00047] A second aspect of the teachings provides a hydrogen-powered internal combustion engine comprising an engine starting system, in accordance with the first aspect of the present teachings.

[00048] A third aspect of the present teachings provides a working machine comprising a motor, in accordance with the second aspect of the present teachings.

[00049] A fourth aspect of the teachings provides a method for starting a hydrogen-powered internal combustion engine comprising at least one fuel ignition device and a hydrogen fuel supply system, the method comprising the steps of: a) upon receiving an engine start command, instruct the ignition of the fuel ignition device without instructing the start of fuel supply; b) monitor an output from the fuel ignition device for a signal indicating the generation of a spark.

[00050] Optionally, the method also includes a step c) after step b) of, upon detecting a spark, instructing the supply of hydrogen fuel for combustion in the engine.

[00051] Optionally, the method further comprises a step d) after step b) of performing the drying operation on at least one fuel ignition device when it is determined that the ignition of the fuel ignition device was not successful. Petition 870250081175, dated 10 / 09 / 2025, pp. 56 / 102 8 / 21

[00052] Optionally, the method also includes a step e) of determining whether the internal combustion engine fuel supply system is free of excess hydrogen before instructing the ignition of at least one fuel ignition device. BRIEF DESCRIPTION OF THE DRAWINGS

[00053] The modalities will now be disclosed by way of example, with reference only to the drawings, in which: Figure 1 is a schematic plan view of an internal combustion engine and control system according to one embodiment of the present teachings; Figure 2 is a cross-sectional view of the internal combustion engine shown in Figure 1, vertically through the cylinder head, showing the intake and exhaust systems; Figure 3 is a flowchart of an engine starting process, according to one of the methods presented here; Figure 4 is a flowchart of an engine shutdown process, according to one of the methods presented here; and Figure 5 is a side view of an exemplary work machine incorporating an internal combustion engine from Figure 1. DETAILED DESCRIPTION

[00054] In the detailed description that follows, several specific details are presented to provide a complete understanding of the various embodiments and the inventive concept. However, those versed and skilled in the technical field will understand that the present teachings can be practiced without these specific details or with known equivalents of these specific details; that the present teachings are not limited to the embodiments described; and that the present teachings can be practiced in various alternative embodiments. It will also be understood that methods, procedures, Petition 870250081175, dated 10 / 09 / 2025, page 57 / 102 9 / 21 well-known components and systems may not have been described in detail.

[00055] Referring initially to Figures 1 and 2, one embodiment includes an internal combustion engine 1. Figure 1 shows a schematic plan view of engine 1 and Figure 2 shows a vertical cross-section of a cylinder and cylinder head of the engine of Figure 1.

[00056] Engine 1 is a four-stroke gas-fuel IC engine configured to be powered by hydrogen.

[00057] Engine 1 may be suitable for use as the primary engine in a work machine 10, see Figure 5, which represents a backhoe loader, but it may also be a telescopic handler, a forklift, a wheeled loader, a dump truck, an excavator or a tractor, for example. These work machines 10 are suitable for use in off-road applications such as agriculture, forestry and construction. In these industries, they are generally configured to perform tasks such as digging, handling loads, harvesting or planting crops. Engine 1 may also be used in a generator – a self-contained unit to provide electrical power in off-grid locations. As such, engine 1 typically needs to have certain characteristics, such as high torque output over a wide engine speed range, with peak torque occurring at a relatively low engine speed, which differs from light passenger vehicles, for example.In off-road applications, this provides a “torque reserve” that allows the work machines 10 to continue performing work operations when they encounter increased loads or resistance to a work operation, for example, an excavator encountering a particularly solid piece of ground to be excavated.

[00058] In this configuration, engine 1 has four sets of cylinders, usually indicated as 19. As configured, Petition 870250081175, dated 10 / 09 / 2025, pp. 58 / 102 10 / 21 The engine has a maximum power output of approximately 55 kW, although it is understood that the present teachings are applicable to engines with a wide range of power outputs. In the present embodiment, the engine has a total displacement of 4.4 liters (i.e., 1.1 liters per cylinder). In engines used in off-road applications, each cylinder may typically have a displacement between 0.75 and 1.5 liters. This displacement is relatively high compared to passenger vehicle engines, but it is adequate to provide the operating characteristics described above.

[00059] In this embodiment, engine 1 is powered exclusively by hydrogen. In other embodiments, engine 1 may be powered by hydrogen in combination with other fuels, such as natural gas.

[00060] Each set of cylinders 19 includes a cylinder 5 with a bifurcated intake port 6 (a single one visible for clarity) and a bifurcated exhaust port 9 (visible only in Figure 2), a translationally movable piston 20 within cylinder 5, an intake channel 16 that runs from an intake manifold 11 to the intake port 6, and a fuel injector 22.

[00061] Each set of cylinders 19 is configured to selectively inject a hydrogen gaseous fuel from fuel injector 22 into intake channel 16.

[00062] Each intake port 6 is selectively opened and closed by intake valves 7i (one visible, but two intake valves 7i per cylinder 5). Each exhaust port 9 is selectively opened and closed by two exhaust valves 7e (one visible in Figure 2) per cylinder 5.

[00063] Engine 1 is configured to supply gaseous hydrogen fuel and air from intake port 16 to cylinder 5 via intake port 6 during an intake stroke of Petition 870250081175, dated 10 / 09 / 2025, pages 59 / 102 11 / 21 piston 20, and exhaust combustion gases from cylinder 5 through the exhaust port 9 during an exhaust stroke of piston 20.

[00064] In alternative embodiments (not shown), engine 1 may have more or fewer cylinder sets 19, for example, 2, 3, 6 or 8. Furthermore, in other embodiments, the cylinders 5 may be oriented in a V or boxer configuration, instead of in line, as in the disclosed embodiment.

[00065] Engine 1 comprises a cylinder block 2 and a cylinder head 3. The cylinder block 2 includes the cylinders 5. The cylinder head 3 includes at least a portion of the intake port 16 of each set of cylinders 19.

[00066] Cylinder head 3 is mounted on cylinder block 2. Intake manifold 11 is mounted on cylinder head 3. Engine 1 is configured so that intake ports 16 supply a mixture of air from intake manifold 11 and fuel from injectors 22 to the corresponding cylinders 5 of cylinder block 2 via intake port 6. As such, engine 1 is a port fuel injection engine (i.e., fuel is supplied to cylinders 5 via fuel injection at the intake port).

[00067] In other configurations, the engine may instead be direct injection, meaning that hydrogen fuel is injected directly into each cylinder via injectors located on the roof of each cylinder.

[00068] In the illustrated embodiment, a fuel supply system 50, comprising a fuel injector 22 in fluid communication with a common fuel rail 52, is supplied with gaseous hydrogen fuel from a fuel tank 12 (Figure 5). The supply can be isolated by a fuel supply valve 54 at the upstream end of the common fuel rail 52. Petition 870250081175, dated 10 / 09 / 2025, pages 60 / 102 12 / 21

[00069] Since engine 1 uses hydrogen as fuel, a spark is required to initiate combustion. Thus, each cylinder assembly 19 comprises a spark plug 21 (illustrated schematically) mounted between the intake and exhaust ports 6, 9 in the cylinder head 3. The spark plugs 21 are connected to their respective coils 23 which generate a high-voltage current to initiate the spark at the spark plug, as needed, during the combustion cycle of engine 1. Each spark plug 21 and its respective coil 23 are collectively referred to as a fuel ignition device.

[00070] Engine 1 includes a crankshaft 14 coupled to each piston 20. Engine 1 is configured so that the translational movements of each piston 20 are converted into rotational movement of the crankshaft 14 around a rotating axis thereof. The rotation of the crankshaft 14 drives a camshaft (not shown), which moves the intake valves 7i and the exhaust valves 7e between the open and closed positions. An electric starter motor 24 is provided to rotate the crankshaft 14 and start engine 1.

[00071] With reference to Figure 1, motor 1 includes a controller 150 configured to control the operation of motor 1. The controller 150 may be an engine control unit (ECU).

[00072] Controller 150 may comprise any circuit suitable for controlling motor 1 and following the control methods described herein. The controller may comprise: control circuits; and / or processor circuits; and / or at least one application-specific integrated circuit (ASIC); and / or at least one field-programmable gate array (FPGA); and / or single or multiple processor architectures; and / or sequential / parallel architectures; and / or at least one programmable logic controller (PLC); and / or at least one Petition 870250081175, dated 10 / 09 / 2025, pages 61 / 102 13 / 21 microprocessor; and / or at least one microcontroller; and / or a central processing unit (CPU), to execute the methods described. The controller 150 comprises, in this embodiment, a microprocessor 152 and an associated memory 152. The memory 152 may be a non-volatile flash memory.

[00073] As part of its control function, the controller 150 communicates with the fuel injectors 22, coils 23, starter motor 24 and fuel supply valve 54. The controller 150 monitors the crankshaft rotation 14 by means of a crankshaft sensor 25 and can monitor the fuel pressure in the common fuel rail 52 by means of a pressure sensor 53. In addition, the controller 150 receives inputs from an engine starting device 156, such as a switch, button and / or touch screen operable by a machine operator, and also sends status information to a visual and / or audible output 158, such as a lamp, buzzer and / or multifunction display, for example, on a panel inside the cab or on an operator panel.It is important to note that, although these signal links are represented in Figure 1 as direct links, they may in fact be provided through intermediate controllers that control other parts of an overall machine, such as a controller for fuel supply (not shown). Furthermore, communication may, in some cases, be done via a network link, such as a CAN bus.

[00074] With reference to Figure 3, a motor starting process according to one modality will be described below.

[00075] In step S100, the process begins when the starting device 156 of motor 1 is switched on to a first condition in which the motor's electrical systems, including the controller 150, are activated. In step S102, the controller 150 performs pre-start checks, which are not part of these teachings, to confirm that motor 1 is ready. Petition 870250081175, dated 10 / 09 / 2025, pages 62 / 102 14 / 21 to start and, otherwise, emits a fault code in step S104 and prevents the engine from starting.

[00076] If the checks in step S102 are approved, controller 150 monitors a motor start request in step S106, for example, the operator placing motor starting device 156 in a second condition to request the start of motor 1.

[00077] In step S108, the controller queries memory 154 to obtain a flag indicating that a previous motor shutdown process (described in more detail below) has been completed. If the flag indicates that the process was not completed, due to a motor stop or emergency shutdown, for example, controller 150 signals for a motor purge operation to be performed in step S110.

[00078] An emergency shutdown may occur when an operator shuts down the engine via an isolating switch (not shown) instead of using the engine starting device 156. These isolating switches are a legal requirement on work machines to isolate the machine's electrical system for safety reasons during maintenance, but are sometimes used by operators as a shortcut to stop an engine from outside the cab. An emergency shutdown may also occur if an engine or after-treatment fault detected by the controller 125 requires an immediate shutdown.

[00079] In a purge operation, the controller signals the starter motor 24 to start the engine 1 without signaling the ignition of the coils 23 to initiate a spark at the spark plugs 21, as well as to open a throttle valve (not shown) in the air intake path, at least partially, to facilitate airflow. It has been observed that, under some circumstances, hydrogen held under pressure (approximately 10 bar) in the common fuel rail 52 may leak through the fuel injector nozzles 22 and then, Petition 870250081175, dated 10 / 09 / 2025, pp. 63 / 102 15 / 21 will accumulate in cylinders 5, intake ports 16 and / or intake manifold 11. This purge operation removes unburned hydrogen from these locations, which is desirable as it minimizes the risk of a thermal event or backfire outside the cylinder that could damage engine components 1 if the engine starts with this excess hydrogen.

[00080] In this mode, controller 150 signals the purge operation to run for a predetermined time, which is calculated as being sufficient to displace the volume of hydrogen retained within the common fuel rail 52 to its operating pressure when expanded to atmospheric pressure, the engine displacement 1, and the volume of the air induction system. Typically, this may equate to a time of approximately 1 to 3 seconds. In other modes, the controller may instead signal the purge operation to run for a predetermined number of crankshaft revolutions. The crankshaft sensor 25 associated with crankshaft 14 may be used by controller 150 to monitor the number of revolutions, for example.

[00081] In this mode, the injectors 22 are not opened during the purge operation, so any hydrogen still retained within the common fuel rail 52 is retained. In other modes, the injectors 22 are opened (but with the fuel supply valve 54 closed) to also purge the common fuel rail 52. In this mode, the controller 150 can monitor the fuel rail pressure through the pressure sensor 53. Pressure that has reached a level close to atmospheric pressure can be considered an indication that the purge operation has been completed.

[00082] To indicate to the operator that the purge operation is taking place, controller 150 can provide an output to audiovisual device 158. Petition 870250081175, dated 10 / 09 / 2025, pp. 64 / 102 16 / 21

[00083] It should also be noted that steps S108 and S110 may occur before S106. However, this may be considered unexpected by the operator if the engine starts without a start request.

[00084] Once the purge is complete (or if no purge was required), the process moves to step S112. In this step, the controller signals the ignition of each of the coils 23 to check for spark generation, without opening the injectors 22 to supply hydrogen to cylinders 5. In this mode, the coils 23 are intelligent and provide feedback to the controller 150 based on the coil discharge time, which indicates whether a spark is generated or whether contamination of the spark plugs 21 by water or oil impairs their operation (absence of spark or weak spark). This step may also require starting the engine if the ignition of the coils 23 requires it, or it may be possible through simultaneous ignition of all coils or faster than would be possible with engine 1 running.

[00085] If controller 150 determines that any of the spark plugs 21 is wet from the feedback, in step S114, it performs a drying operation on spark plug 21. In this operation, the controller signals the activation of coils 23 and the starting of engine 1 without the introduction of hydrogen fuel. The current passing through the spark plugs, combined with the airflow through the cylinder from starting, promotes the removal of water from the spark plugs 21. In other modes, controller 150 may signal only the activation of coils 23 or only the starting to promote drying.

[00086] To indicate to the operator that the spark plug drying operation is taking place, controller 150 can provide an output to audiovisual device 158. Petition 870250081175, dated 10 / 09 / 2025, pages 65 / 102 17 / 21

[00087] The operation continues for a predetermined period of time, a predetermined number of starting revolutions, or until diagnostic feedback indicates that all spark plugs are reliably producing sparks. An upper time or revolution limit is placed on the operation to prevent the engine battery from depleting. If this limit is reached and ignition is not detected at all spark plugs 21 in step S116, the controller registers a fault code in step S118, prevents engine 1 from starting, and may display an appropriate error message via audiovisual output 158.

[00088] If combustion is detected in engine 1 during the spark plug drying operation, for example, through an increase in engine speed above the crankshaft speed, as detected by the crankshaft speed sensor 25, this is indicative of the unexpected presence of fuel. In this situation, the drying operation is aborted.

[00089] In step S120, if the operation manages to dry the spark plugs 21, the controller starts supplying fuel through the injectors 22 so that the engine 1 can function normally.

[00090] However, monitoring of coil 23 continues. If combustion is not detected in all cylinders 5 in step S122, for example, if the engine is running on only three cylinders, controller 150 signals injector 22 for that cylinder to stop fuel supply for a predetermined period in step S124, allowing the remaining cylinders to continue running. This prevents unburned hydrogen from being expelled from engine 1, which is undesirable from an environmental and safety standpoint. However, as in the drying operation of step S114, airflow and continuous ignition can dry out spark plug 21. If coil diagnostics indicate in step S126 that ignition has been detected, fuel supply to that cylinder is interrupted. Petition 870250081175, dated 10 / 09 / 2025, pages 66 / 102 Cylinder 18 / 21 is restarted in step S120. This is achieved with engine 1 running in this mode or, in another mode, requiring an operator to stop and restart engine 1.

[00091] If, after the predetermined period, for example, within a range of 30 to 180 seconds, no spark is detected in step S126, the controller signals the engine shutdown (according to the process established in Figure 4 and described below) and also registers a fault code for diagnostic purposes in step S128. This command prevents prolonged operation with limited cylinders, compromising the engine's operation and / or durability.

[00092] If combustion is detected in all cylinders 5 during step S122, the starting process is considered successful and complete, allowing engine 1 to function normally.

[00093] In a variant of steps S116, S120 and S122, if, in step S116, the drying operation reaches the time limit and spark formation is detected, for example, in three of the four cylinders 5, the controller can proceed to step S120 instead of S118 and supply fuel only to the operating cylinders and monitor the drying and spark formation of the spark plug 21 of the remaining cylinder 5. This can minimize inconvenience for the operator, as it can avoid the need for maintenance personnel to repair the engine 1.

[00094] Referring now to Figure 4, we describe an engine shutdown process. The process is configured to completely or partially empty the common fuel rail 52 of pressurized hydrogen fuel before the complete shutdown of engine 1. This minimizes the risk of hydrogen leakage from the fuel injectors while engine 1 is off, remaining in cylinders 5, intake manifold 11 and intake channels 16 and then being ignited uncontrollably when the engine is restarted, which could cause engine damage. Petition 870250081175, dated 10 / 09 / 2025, pages 67 / 102 19 / 21

[00095] The process begins with engine 1 running and, in step S200, the controller monitors the engine idle time and, if the engine is idle for a predetermined period (e.g., five minutes), determines that automatic engine shutdown should be initiated as a fuel-saving measure and proceeds to step S204. If the idle limit has not been reached, the controller monitors a switch-off signal from the engine starter device 156 in step S202. If no switch-off request is detected, the process returns to the beginning. If a switch-off request is detected, the process also proceeds to step S204.

[00096] In step S204, controller 150 signals the closing of the fuel supply valve 54, blocking fuel flow to the common fuel rail 52, before initiating a shutdown timer in step S206 and signaling the interruption of ignition of half of the spark plugs 21 and the interruption of fuel injection in the cylinders 5 corresponding to the unfired spark plugs in step S208. In step S210, controller 150 then adjusts the engine operating parameters to run the engine with a rich mixture (i.e., with a higher fuel-to-air ratio), extending the fuel injection window in the operating cylinders 5.

[00097] Rich operation causes hydrogen to burn more quickly, thus minimizing the prolonged operating period, which is desirable from the operator's acceptance standpoint. However, in hydrogen-powered engines, rich operation has been associated with a higher risk of combustion product (water) wetting the spark plugs 21. Thus, the prior step of shutting off the fuel and combustion of two cylinders reduces the risk of these cylinders having wet spark plugs 21, meaning that a restart Petition 870250081175, dated 10 / 09 / 2025, pages 68 / 102 The subsequent 20 / 21 engine will likely be more successful. The increased fuel consumption due to rich running more than compensates for the reduction in fuel consumption due to half of the cylinders being deactivated.

[00098] In a variant of the S208 and S210 steps that can be employed for direct injection engines, in particular, a standard fuel mixture (as determined by a map or lookup table normally employed by the engine ECU) can be supplied to some cylinders and rich running to other cylinders, with the similar aim of reducing the risk of wetting in some cylinders to aid in engine restart.

[00099] In other modes, one or both steps S208 and S210 may be omitted. [000100] In step S212, controller 150 determines whether the shutdown timer has reached its predetermined extended operating duration. This duration is defined based on the calculation of the time required for the number of engine revolutions to displace the volume of hydrogen retained in the common fuel rail 52 to its operating pressure when expanded to atmospheric pressure. Typically, this may equate to a time of approximately 1 to 3 seconds. In other embodiments, the controller may instead signal the spark plugs 21 to fire and the injectors 22 to operate for a predetermined number of crankshaft revolutions necessary to empty the common fuel rail 52. [000101] In other embodiments, the controller 150 can monitor the fuel rail pressure 52 via the pressure sensor 53. Once this has been reduced to a limit pressure at which the remaining hydrogen fuel would not pose a risk of engine damage if it leaked from the injectors (e.g., less than 2.5 bar, optionally less than 2 bar down to or near atmospheric pressure). If a Petition 870250081175, dated 10 / 09 / 2025, pages 69 / 102 21 / 21 positive pressure is maintained, this can reduce the risk of debris entering the common fuel rail 52. [000102] So, in step S214, controller 150 stores a shutdown completed flag in memory 154 to be used in step S108 of the motor starting process in Figure 3. If the motor stops abnormally, for example, due to a shutdown or an emergency stop (via a motor isolating switch), this flag will not be set, or a different flag will be set, so that, in the starting process, controller 150 performs the purge operation of step S110. [000103] In step S216, controller 150 signals the closing of injectors 22 and coils 23 to interrupt ignition and shut down engine 1, and the process is complete. [000104] If the engine cannot be started and a service visit is required, the service technician may use a service tool to perform a drying operation or the fault code may indicate the removal and physical drying of any affected spark plugs 21 as needed. [000105] The one or more embodiments described above are merely examples, and it should be understood that variations are possible without departing from the scope of protection conferred by the appended claims. For example, if the engine is equipped with an electric starter or generator (e.g., a hybrid engine), it can be used to start the engine and purge the fuel. Petition 870250081175, dated 10 / 09 / 2025, pp. 70 / 102

Claims

1 / 5 CLAIMS 1. Engine starting system for a hydrogen-powered internal combustion engine (1), the system comprising: a controller (150); at least one fuel ignition device (21, 23) in communication with the controller (150); and a hydrogen fuel supply system (50) in communication with the controller (150); CHARACTERIZED in that the system is configured in such a way that, upon receiving an engine start command, the controller (150) is configured to instruct the ignition of the fuel ignition device (21, 23) without instructing the start of fuel supply and is configured to monitor an output from the fuel ignition device (21, 23) for a signal indicating the generation of a spark.

2. Engine starting system, according to claim 1, CHARACTERIZED in that, upon detection of a spark, the controller (150) is configured to instruct the supply of fuel for combustion in the engine (1).

3. Engine starting system, according to claim 1, CHARACTERIZED in that the controller (150) is additionally configured to determine whether the fuel supply system (50) of the internal combustion engine (1) is free of excess hydrogen before instructing the ignition of at least one fuel ignition device (21, 23).

4. Engine starting system, according to any of the claims, CHARACTERIZED in that the controller (150) is additionally configured to instruct a drying operation of at least one fuel ignition device (21, 23) upon determining that the ignition of the fuel ignition device (21, 23) was not successful, optionally, wherein in the drying operation of the fuel ignition device, the controller (150) signals the ignition of the fuel ignition device(s) (21, 23) that was determined to be wet.

5. Engine starting system according to claim 4, CHARACTERIZED in that the drying operation of the fuel ignition device (21, 23) comprises starting the engine (1) without fuel supply.

6. Engine starting system, according to claim 4 or 5, CHARACTERIZED in that, during the drying operation, the controller (150) is configured to monitor the output of the fuel ignition device (21, 23) for a signal indicating the generation of a spark.

7. Engine starting system, according to claim 6, CHARACTERIZED in that, in the event that a signal indicating the generation of a spark is detected, the controller (150) is configured to instruct the interruption of the drying operation and to instruct the fuel supply to a cylinder (5) of the engine corresponding to the fuel ignition device 21, 23), optionally, wherein the controller (150) is configured to, after instructing the fuel supply, monitor the combustion of the fuel in the cylinder (5).

8. Engine starting system, according to claim 7, CHARACTERIZED in that the controller (150) is configured to instruct the interruption of the fuel supply to cylinder (5) and to instruct the generation of a spark for that cylinder (5), if no combustion is detected, optionally, wherein the controller (150) is configured to instruct the fuel supply to cylinder (5) in the event that a spark is detected for that cylinder (5).

9. Engine starting system, according to any one of claims 3 or 4 to 8, when dependent on claim 3, CHARACTERIZED in that the controller (150) is Petition 870250081175, dated 10 / 09 / 2025, page 72 / 102 3 / 5 configured to determine whether the engine (1) is free of excess hydrogen, confirming the completion of a previous engine shutdown procedure configured to clear excess hydrogen from the fuel supply system before complete engine shutdown (1).

10. Engine starting system, according to any one of claims 3 or 4 to 9, when dependent on claim 3, CHARACTERIZED in that the controller (150) is configured to instruct a hydrogen purge operation in the event that it is determined that the internal combustion engine (1) is not free of excess hydrogen, optionally, wherein, when instructing the hydrogen purge operation, the controller (150) is configured to instruct the starting of the engine (1) without instructing the ignition of the fuel ignition device (21, 23), so as to purge the hydrogen from the engine (1).

11. Engine starting system, according to claim 10, CHARACTERIZED in that the controller (150) is additionally configured to instruct the hydrogen fuel supply system (50) not to supply fuel during purge operation.

12. Engine starting system, according to claim 10 or 11, CHARACTERIZED in that the controller (150) is configured to instruct purge operation for a predetermined time or for a predetermined number of engine revolutions.

13. Engine starting system, according to any of the preceding claims, CHARACTERIZED in that at least one fuel ignition device (21, 23) comprises an ignition coil (23) and a spark plug (21) and / or in that the hydrogen fuel supply system (50) comprises at least one fuel injector (22) optionally in fluid flow communication with a common fuel rail (52). Petition 870250081175, dated 10 / 09 / 2025, p. 73 / 102 4 / 5 14. Engine starting system, according to any of the claims, CHARACTERIZED in that the engine (1) comprises a plurality of cylinders (5).

15. Engine starting system, according to claim 14, when dependent on claim 6, CHARACTERIZED in that the controller (150) is configured to instruct the interruption of the drying operation only in the event that a signal indicating the generation of a spark is detected in the fuel ignition devices (21, 23) corresponding to each of the plurality of cylinders (5).

16. Hydrogen-powered internal combustion engine (1), CHARACTERIZED in that it comprises an engine starting system as defined in any of the preceding claims.

17. Method for starting a hydrogen-powered internal combustion engine (1), comprising at least one fuel ignition device (21, 23) and a hydrogen fuel supply system (50), the method CHARACTERIZED in that it comprises the steps of: a) upon receiving a start command from the engine, instructing the ignition of the fuel ignition device (21, 23) without instructing the start of fuel supply; b) monitoring an output from the fuel ignition device (21, 23) for a signal indicating the generation of a spark.

18. Method according to claim 17, CHARACTERIZED in that it further comprises a step c) after step b), upon detecting a spark, to instruct the supply of hydrogen fuel for combustion in the engine (1).

19. Method, according to claim 17 or 18, CHARACTERIZED in that it additionally comprises a step d) after step b) to perform the drying operation of at least one fuel ignition device (21, 23) when Petition 870250081175, dated 10 / 09 / 2025, page 74 / 102 5 / 5 to determine that the spark from the fuel ignition device (21, 23) was not successful.

20. Method, according to any one of claims 17 to 19, CHARACTERIZED in that it additionally comprises a step e) for determining whether the fuel supply system (50) of the internal combustion engine (1) is free of excess hydrogen before instructing the ignition of at least one fuel ignition device (21, 23). Petition 870250081175, dated 10 / 09 / 2025, pp. 75 / 102

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