An engine control system

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 the fuel ignition device to ignite without instructing fuel supply to commence, and is configured to monitor the output of the fuel ignition device to obtain a signal indicative of spark generation.

Description

Technical Field

[0001] This invention relates to engine control systems. Specifically, it relates to an engine starting system for a hydrogen fuel cell internal combustion engine. Furthermore, it relates to an engine shutdown system and a method for operating / starting and / or shutting down a hydrogen fuel cell internal combustion engine. Background Technology

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

[0003] In order to reduce emissions from internal combustion engines and potentially reduce greenhouse gases, hydrogen is being proposed as a fuel for such engines, replacing diesel or gasoline.

[0004] Due to the inherent properties of hydrogen, under certain circumstances, over time, hydrogen can leak from the fuel rail through the injectors into the intake system and / or cylinders of an internal combustion engine. Under the operating pressures within the shared fuel rail, and given its compressible nature, a significant amount of hydrogen may thus remain trapped in these areas of the engine.

[0005] Therefore, when the engine is subsequently restarted, there is a risk of hydrogen causing a heating event or backfire, which could damage engine components, which is obviously undesirable. There is also a risk of hydrogen escaping into the environment, which is also undesirable, as unburned hydrogen is itself a greenhouse gas.

[0006] Furthermore, the primary byproduct of hydrogen combustion in an internal combustion engine is water. There is a perceived high risk of water scaling on spark plugs used in hydrogen-fueled internal combustion engines. This can prevent hydrogen combustion in one or more cylinders of the engine, potentially causing the engine to either not run at full capacity or only operate with a reduced number of cylinders. In the latter case, this can lead to unwanted hydrogen emissions, reduced engine power output, and / or damage to engine components.

[0007] The present invention aims to overcome or at least mitigate the problems existing in the prior art. Summary of the Invention

[0008] A first aspect of the present invention provides an engine starting system for a hydrogen fuel cell internal combustion engine. The system may include: a controller; at least one fuel ignition device in communication with the controller; and / or a hydrogen fuel delivery system in communication with the controller. The system may be configured such that, upon receiving an engine start command, the controller is configured to instruct the fuel ignition device to ignite, without instructing the start of fuel supply, and may also be configured to monitor the output of the fuel ignition device to obtain a signal indicating the generation of a spark.

[0009] Alternatively, this arrangement prevents unburned hydrogen from being emitted from the engine due to the lack of a spark in the engine cylinders. From a safety and environmental perspective, the emission of unburned hydrogen is undesirable.

[0010] Optionally, upon detecting a spark, the controller is configured to instruct the supply of fuel for combustion in the engine.

[0011] Alternatively, once a spark is detected, it is appropriate to supply fuel, as the fuel will be burned rather than released into the atmosphere.

[0012] Optionally, the controller is also configured to determine whether excess hydrogen has been purged from the fuel delivery system of the internal combustion engine before instructing at least one fuel ignition device to ignite.

[0013] Alternatively, this ensures that if there is a risk of hydrogen burning in the engine in an uncontrolled manner that could damage the engine, the controller can avoid performing ignition.

[0014] Optionally, the controller is also configured to instruct at least one fuel ignition device to perform a drying operation when it is determined that the ignition of the fuel ignition device has failed.

[0015] Alternatively, this can allow the engine to run normally without requiring specialized maintenance.

[0016] Optionally, during the fuel ignition device drying operation, the controller sends an ignition signal to the fuel ignition device or each fuel ignition device that is determined to be wet.

[0017] Alternatively, the ignition operation promotes the drying of the ignition device by means of the current flowing through it.

[0018] Ignition can typically occur multiple times. In some systems, ignition may only be combined with the engine starting according to the normal engine cycle, but in other systems, ignition may occur independently of starting and therefore may happen at a higher frequency.

[0019] Optionally, the fuel ignition drying operation includes starting the engine without supplying fuel.

[0020] Alternatively, starting the engine promotes airflow through the fuel ignition device, thereby promoting the drying of the fuel ignition device.

[0021] Optionally, during the drying operation, the controller is configured to monitor the output of the fuel ignition device to obtain a signal indicating the generation of a spark.

[0022] This signal indicates that the drying operation was successful.

[0023] Optionally, upon detecting a signal indicating the generation of a spark, the controller is configured to instruct the drying operation to stop and to instruct the supply of fuel to the engine cylinder corresponding to the fuel ignition device.

[0024] Optionally, if the fuel ignition system is dry, this allows for minimizing engine start-up delays.

[0025] Optionally, the controller is configured to monitor fuel combustion in the cylinder after indicating fuel supply.

[0026] Although dry fuel ignition systems are easy to ignite, it is beneficial to check whether combustion will result in combustion in order to avoid unburned hydrogen being released into the environment around the engine.

[0027] Optionally, the controller is configured to instruct the supply of fuel to the cylinder to stop and to instruct the generation of a spark for the cylinder if combustion is not detected.

[0028] Optionally, this provides an opportunity for re-drying, especially if the engine can run with fewer cylinders than all cylinders if other cylinders are burning fuel, and those cylinders that are not running can be allowed to re-dry.

[0029] Optionally, the controller is configured to instruct the supply of fuel to the cylinder if a spark is detected for the cylinder.

[0030] Optionally, once the relevant fuel ignition device is dry, this allows for seamless engine operation.

[0031] Optionally, the controller is configured to determine whether the engine has purged excess hydrogen by confirming whether a previous normal engine shutdown procedure has been completed.

[0032] It is beneficial to purge the hydrogen before shutting off the engine so as not to delay the next engine start-up.

[0033] Optionally, the controller is configured to instruct a hydrogen purging operation if it is determined that the internal combustion engine has not purged excess hydrogen.

[0034] If there is a possibility of excess hydrogen, it is desirable to remove the excess hydrogen before testing the spark for safety reasons, otherwise a backfire event may occur.

[0035] Optionally, the controller is configured to instruct the engine to start, rather than instruct the fuel ignition device to ignite, in order to purge hydrogen from the engine.

[0036] Alternatively, this is an effective way to remove hydrogen without requiring additional engine hardware.

[0037] Optionally, the controller is also configured to instruct the hydrogen fuel delivery system not to supply fuel during purging operations.

[0038] To minimize the volume of hydrogen to be removed, it is desirable not to purge any hydrogen remaining upstream of the hydrogen fuel delivery system.

[0039] Optionally, the controller is configured to indicate the duration of the purging operation for a predetermined time or a predetermined number of engine revolutions.

[0040] Advantageously, these are effective methods for determining when a limited volume of hydrogen in an engine will be purged.

[0041] Optionally, at least one fuel ignition device includes an ignition coil and a spark plug.

[0042] Optionally, the hydrogen fuel delivery system includes at least one fuel injector, which is optionally in fluid communication with a common fuel rail.

[0043] Optionally, the engine includes multiple cylinders.

[0044] Optionally, the controller is configured to instruct the drying operation to stop only if a signal indicating spark generation is detected in the fuel ignition device corresponding to each of the plurality of cylinders.

[0045] To ensure the engine can start successfully, it is desirable that all fuel ignition devices are completely dry.

[0046] A second aspect of the present invention provides a hydrogen fuel cell internal combustion engine, which includes an engine starting system according to the first aspect of the present invention.

[0047] A third aspect of the present invention provides a working machine comprising an engine according to a second aspect of the present invention.

[0048] A fourth aspect of the present invention provides a method for starting a hydrogen fuel cell internal combustion engine, the internal combustion engine including at least one fuel ignition device and a hydrogen fuel delivery system, the method comprising the following steps:

[0049] a. Upon receiving an engine start command, instruct the fuel ignition device to ignite, but do not instruct the fuel supply to begin;

[0050] b. Monitor the output of the fuel ignition device to obtain a signal indicating the generation of a spark.

[0051] Optionally, the method further includes step c) following step b): upon detection of a spark, instructing the supply of hydrogen fuel for combustion in the engine.

[0052] Optionally, the method further includes step d) after step b): if it is determined that the ignition of the fuel ignition device is unsuccessful, performing a drying operation on at least one fuel ignition device.

[0053] Optionally, the method further includes step e): determining whether excess hydrogen has been purged from the fuel delivery system of the internal combustion engine before instructing at least one fuel ignition device to ignite. Attached Figure Description

[0054] Embodiments are now disclosed by way of example only with reference to the accompanying drawings, in which:

[0055] Figure 1 This is a schematic plan view of an internal combustion engine and control system according to an embodiment of the present invention;

[0056] Figure 2 yes Figure 1 The internal combustion engine shown is illustrated in a cross-sectional view perpendicular to the cylinder head, showing the intake and exhaust systems.

[0057] Figure 3 This is a flowchart of the engine startup process according to an embodiment of the present invention;

[0058] Figure 4 This is a flowchart of the engine shutdown process according to an embodiment of the present invention; and

[0059] Figure 5 It is a combination Figure 1 A side view of an exemplary working machine with an internal combustion engine. Detailed Implementation

[0060] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments and the invention. However, those skilled in the art will understand that the invention can be practiced without these specific details or known equivalents thereof; the invention is not limited to the described embodiments; and the invention can be practiced in many alternative embodiments. It should also be understood that well-known methods, procedures, components, and systems may not be described in detail.

[0061] First refer to Figure 1 and Figure 2 The embodiment includes an internal combustion engine 1. Figure 1 A schematic plan view of engine 1 is shown. Figure 2 It shows Figure 1 Vertical cross-sectional view of the engine cylinder and cylinder head.

[0062] Engine 1 is a four-stroke gaseous fuel internal combustion engine configured to be powered by hydrogen.

[0063] Engine 1 can be adapted to be used as the prime mover in working machinery 10, see [link / reference] Figure 5 The figure depicts a backhoe loader, but it could also be, for example, a telescopic loader, forklift, wheel loader, dump truck, excavator, or tractor. This type of work machinery 10 is suitable for off-highway applications such as agriculture, forestry, and construction. In these industries, they are typically configured to perform tasks such as digging, loading and unloading, harvesting, or planting crops. The engine 1 can also be used in a generator set (a stand-alone unit that provides power in an off-grid location). Therefore, the engine 1 typically needs to have certain characteristics, such as high torque output over a wide engine speed range, with peak torque occurring at relatively low engine speeds. These characteristics differ from, for example, those of a light passenger vehicle. In off-highway applications, this provides a "torque reserve," allowing the work machinery 10 to continue operating when encountering increased loads or resistance to the work (e.g., an excavator encountering particularly hard soil to be excavated).

[0064] In this embodiment, engine 1 has a four-cylinder assembly, generally designated 19. The maximum power output of the configured engine is approximately 55 kW, although it should be understood that the invention is applicable to engines with a wide range of power outputs. In this embodiment, the total displacement of the engine is 4.4 liters (i.e., 1.1 liters per cylinder). In engines used in off-highway applications, the displacement per cylinder is typically between 0.75 liters and 1.5 liters. This displacement is relatively large compared to passenger car engines, but is suitable for providing the aforementioned operating characteristics.

[0065] In this embodiment, engine 1 uses hydrogen as fuel only. In other embodiments, engine 1 may use a combination of hydrogen and other fuels (e.g., natural gas) as fuel.

[0066] Each cylinder assembly 19 includes a cylinder 5, a piston 20, an intake runner 16, and a fuel injector 22. The cylinder 5 includes a bifurcated intake port 6 (only one is visible for clarity) and a bifurcated exhaust port 9 (only one is visible). Figure 2 As can be seen in the image, the piston 20 can move horizontally within the cylinder 5, and the intake passage 16 leads from the intake manifold 11 to the intake port 6.

[0067] Each cylinder assembly 19 is configured to selectively inject gaseous hydrogen fuel from the fuel injector 22 into the intake passage 16.

[0068] Each intake port 6 is selectively opened and closed by an intake valve 7i (one is visible, but each cylinder 5 has two intake valves 7i). Each exhaust port 9 is opened and closed by two exhaust valves 7e of each cylinder 5. Figure 2 One can be seen in the image (which selectively turns on and off).

[0069] Engine 1 is configured to supply gaseous hydrogen fuel and air from intake passage 16 to cylinder 5 via intake port 6 during the intake stroke of piston 20, and then exhaust combustion gases from cylinder 5 via exhaust port 9 during the exhaust stroke of piston 20.

[0070] In alternative embodiments (not shown), the cylinder assembly 19 of engine 1 may have more or fewer, such as 2, 3, 6, or 8. Furthermore, in other embodiments, the cylinders 5 may be oriented in a "V" configuration or an opposed configuration, rather than in an inline configuration as in the disclosed embodiments.

[0071] Engine 1 includes a cylinder block 2 and a cylinder head 3. Cylinder block 2 includes cylinders 5. Cylinder head 3 includes at least a portion of the intake passage 16 for each cylinder assembly 19.

[0072] The cylinder head 3 is mounted on the cylinder body 2. The intake manifold 11 is mounted on the cylinder head 3. The engine 1 is configured such that the intake passage 16 supplies a mixture of air from the intake manifold 11 and fuel from the injector 22 to the corresponding cylinder 5 of the cylinder body 2 via the intake port 6. Thus, the engine 1 is a port fuel injection engine (i.e., fuel is supplied to the cylinder 5 via port fuel injection).

[0073] In other embodiments, the engine can be modified to be a direct injection type, in which hydrogen fuel is injected directly into each cylinder via an injector located at the top of each cylinder.

[0074] In the illustrated embodiment, the fuel delivery system 50 (including a fuel injector 22 in fluid communication with a common fuel rail 52) is supplied with gaseous hydrogen fuel from the fuel tank 12. Figure 5 This supply can be isolated via a fuel supply valve 54 located upstream of the common fuel rail 52.

[0075] Since engine 1 uses hydrogen as fuel, a spark is required to ignite combustion. Therefore, each cylinder assembly 19 includes a spark plug 21 (shown schematically), which is installed between the intake port 6 and the exhaust port 9 in the cylinder head 3. The spark plug 21 is connected to a corresponding coil 23, which generates a high-voltage current during the combustion cycle of engine 1 to ignite a spark in the spark plug as needed. Each spark plug 21 and its corresponding coil 23 are collectively referred to as a fuel ignition system.

[0076] Engine 1 includes a crankshaft 14 coupled to each piston 20. Engine 1 is configured to convert the translational motion of each piston 20 into rotational motion of crankshaft 14 about its axis of rotation. The rotation of crankshaft 14 drives camshaft (not shown), which moves intake valve 7i and exhaust valve 7e between open and closed positions. An electric starter motor 24 is provided to rotate crankshaft 14 and start engine 1.

[0077] refer to Figure 1 Engine 1 includes a controller 150, which is configured to control the operation of engine 1. Controller 150 may be an engine control unit (ECU).

[0078] Controller 150 may include any suitable circuitry to control engine 1 and follow the control methods described herein. The controller may include: control circuitry; and / or processor circuitry; and / or at least one application-specific integrated circuit (ASIC); and / or at least one field-programmable gate array (FPGA); and / or a single-processor or multi-processor architecture; and / or a serial / parallel architecture; and / or at least one programmable logic controller (PLC); and / or at least one microprocessor; and / or at least one microcontroller; and / or a central processing unit (CPU) to perform the described methods. In this embodiment, controller 150 includes a microprocessor 152 and an associated memory 152. Memory 152 may be non-volatile flash memory.

[0079] As part of its control functions, controller 150 communicates with fuel injector 22, coil 23, starter motor 24, and fuel supply valve 54. Controller 150 monitors the rotation of crankshaft 14 via crankshaft sensor 25 and can monitor fuel pressure in common fuel rail 52 via pressure sensor 53. Furthermore, controller 150 receives input from engine starting device 156 (e.g., a key, button, and / or touchscreen operable by the machine operator) and also outputs status information to visual and / or auditory outputs 158 (e.g., lights, buzzers, and / or multifunction displays), such as on the dashboard in the driver's cab or on the operator's panel. It should be understood that although these signals are connected to… Figure 1 While described as direct links, these can actually be provided via intermediate controllers that control other parts of the machine (e.g., a controller for fuel supply, not shown). Furthermore, in some cases, communication can be connected via a network (e.g., a CAN bus).

[0080] refer to Figure 3 The engine startup process according to an embodiment will now be described.

[0081] In step S100, the process begins when the starting device 156 of engine 1 is turned on to a first state (in which the engine electrical system, including controller 150, is activated). In step S102, controller 150 performs a pre-start check, which is not part of this invention, to confirm that engine 1 can start. If it cannot start, a fault code is output in step S104 and engine starting is prevented.

[0082] If the check in step S102 passes, the controller 150 monitors the engine start request in step S106 (e.g., the operator places the engine start device 156 in the second state to request the engine 1 to start).

[0083] In step S108, the controller queries memory 154 to retrieve a flag indicating that a previous engine shutdown process (described in more detail below) has been completed. If the flag indicates that the process was not completed due to, for example, engine shutdown or emergency shutdown, the controller 150 signals in step S110 to perform an engine purging operation.

[0084] An emergency shutdown may occur when the operator shuts off the engine via a disconnect switch (not shown) instead of using the engine starter 156. This disconnect switch is a legal requirement for operating machinery to isolate the machine's electrical system during maintenance to ensure safety, but sometimes operators use it as a "quick" way to stop the engine from outside the cab. An emergency shutdown may also occur if the controller 125 detects an engine or aftertreatment malfunction requiring immediate shutdown.

[0085] During the purging operation, the controller sends a signal to the starter motor 24 to start the engine 1, but not to the coil 23 to ignite a spark in the spark plug 21, and at least partially opens a throttle valve (not shown) in the intake path to facilitate airflow. It has been observed that, under certain conditions, hydrogen at a pressure of approximately 10 bar in the common fuel rail 52 may leak through the nozzle of the fuel injector 22 and subsequently accumulate in the cylinder 5, intake passage 16, and / or intake manifold 11. This purging operation removes unburned hydrogen from these locations, which is desirable because it minimizes the risk of external cylinder thermal events / backfire events (which could damage engine 1 components if the engine is started with such excess hydrogen).

[0086] In this embodiment, the controller 150 signals to run the purging operation for a predetermined time, which is calculated to be sufficient to expel the following volumes of hydrogen: the volume of hydrogen contained in the common fuel rail 52 at operating pressure (when expanded to atmospheric pressure), the displacement of engine 1, and the volume of the intake system. Typically, this may correspond to approximately 1-3 seconds. In other embodiments, the controller may instead signal to run the purging operation at a predetermined number of crankshaft revolutions. For example, the controller 150 may use a crankshaft sensor 25 associated with crankshaft 14 to monitor the revolutions.

[0087] In this embodiment, injector 22 is not opened during the purging operation, allowing any hydrogen remaining in the common fuel rail 52 to be retained. In other embodiments, injector 22 is opened (but fuel supply valve 54 is closed) to purge the common fuel rail 52 simultaneously. In this embodiment, controller 150 can monitor fuel rail pressure via pressure sensor 53. Pressure that has reached near atmospheric pressure can be considered an indication that the purging operation is complete.

[0088] To indicate to the operator that a purging operation is in progress, the controller 150 can provide output to the audio / video device 158.

[0089] It should also be understood that steps S108 and S110 can occur before S106. However, if the engine starts without a starting request, the operator may consider this unexpected.

[0090] Once the purging is complete (or if purging is not required), the process then moves to step S112. In this step, the controller sends an ignition signal to each coil 23 to check for spark generation without opening the injector 22 to supply hydrogen to cylinder 5. In this embodiment, the coils 23 are "intelligent" and provide feedback to the controller 150 based on the coil discharge time, indicating whether a spark has been generated or whether the spark plugs 21 are contaminated with water or oil, affecting their operation (no spark or weak spark). This step may also require engine starting (if ignition of the coils 23 is required), or it may be achieved by simultaneously igniting all coils or igniting all coils faster than when engine 1 is started.

[0091] If the controller 150 determines from feedback that any spark plug 21 is wet, then in step S114, the controller 150 performs a spark plug 21 drying operation. In this operation, the controller signals the coil 23 to ignite and the engine 1 to start, without introducing hydrogen fuel. The current through the spark plug, combined with the airflow through the cylinder from the starting engine, facilitates the removal of water from the spark plug 21. In other embodiments, the controller 150 may only signal the coil 23 to ignite, or only signal the engine to start, to facilitate drying.

[0092] To indicate to the operator that the spark plug drying operation is in progress, the controller 150 can provide an output to the audio / video device 158.

[0093] The operation continues for a predetermined time, a predetermined crankshaft speed, or until diagnostic feedback indicates that all spark plugs have reliably ignited. To prevent the engine battery from running out, a time or speed limit is set for the operation. If this limit is reached, and all spark plugs 21 are not detected to have ignited in step S116, the controller records a fault code in step S118, prevents engine 1 from starting, and can display appropriate error information via audio / video output 158.

[0094] If combustion is detected within engine 1 during the spark plug drying operation (e.g., via an increase in engine speed exceeding the crankshaft speed detected by crankshaft speed sensor 25), this indicates the presence of unwanted fuel. In this case, the drying operation will be terminated.

[0095] In step S120, if the operation successfully dries the spark plug 21, the controller begins to supply fuel via the injector 22 so that the engine 1 can operate normally.

[0096] However, monitoring by coil 23 continues. If combustion is not detected in all cylinders 5 in step S122 (e.g., the engine is only running on three cylinders), then in step S124, controller 150 sends a signal to injector 22 of that cylinder to stop fuel supply for a predetermined period of time, while allowing the remaining cylinders to run. This prevents unburned hydrogen from being released from engine 1, which is undesirable from an environmental and safety perspective. However, similar to the drying operation in step S114, the airflow and continuous ignition dry the spark plug 21. If coil diagnostics indicate that ignition is detected in step S126, then fuel supply to that cylinder resumes in step S120. In this embodiment, this is achieved while engine 1 is running, or in another embodiment, by requiring the operator to stop and restart engine 1.

[0097] If ignition is not detected in step S126 after a predetermined time period (e.g., within the range of 30 to 180 seconds), the controller issues a signal to shut down the engine (according to...). Figure 4 (The process shown and described below) and in step S128, a fault code for diagnostic purposes is recorded. This command prevents prolonged operation on a limited number of cylinders, which could impair engine operation and / or durability.

[0098] If combustion is detected in all cylinders 5 in step S122, the starting process is considered successful and completed, allowing engine 1 to operate normally.

[0099] In a variation of steps S116, S120, and S122, if the drying operation times out in step S116 and ignition is detected in three of the four cylinders 5, the controller can move to step S120 instead of S118, supplying fuel only to the working cylinders and monitoring the drying and ignition of the spark plugs 21 in the remaining cylinders 5. This minimizes operator inconvenience by avoiding the need for maintenance personnel to be present to repair engine 1.

[0100] Now for reference Figure 4 The document describes the engine shutdown process. This process is configured to completely or partially evacuate the pressurized hydrogen fuel in the common fuel rail 52 before the engine 1 comes to a complete stop. This minimizes the risk of hydrogen leaking through the fuel injector nozzles when the engine 1 is shut down, remaining in the cylinder 5, intake manifold 11, and intake passage 16, and then being ignited uncontrollably upon engine restart (which could potentially damage the engine).

[0101] The process begins with engine 1 running, and in step S200, the controller monitors the engine idling time. If the engine has been idling for a predetermined period (e.g., five minutes), it determines that the engine will be automatically shut off as a fuel-saving measure, and then proceeds to step S204. If the idling threshold is not reached, in step S202, the controller monitors for a shutdown signal from the engine starter 156. If no shutdown request is detected, the process returns to the beginning. If a shutdown request is detected, the process also proceeds to step S204.

[0102] In step S204, the controller 150 sends a signal to close the fuel supply valve 54, preventing fuel from flowing into the common fuel rail 52. Then, in step S206, it starts a shutdown timer, and in step S208, it sends a signal to stop the ignition of half of the spark plugs 21, stopping fuel injection into the cylinder 5 corresponding to the unignited spark plug. In step S210, the controller 150 then adjusts the engine operating parameters to make the engine fuel-rich (i.e., with a higher air-fuel ratio) by extending the fuel injection window on the operating cylinder 5.

[0103] Fuel-rich operation allows hydrogen to burn more quickly, thus minimizing extended run-time, which is desirable from an operator's perspective. However, in hydrogen fuel cell engines, fuel-rich operation is associated with a higher risk of combustion products (water) wetting the spark plugs 21. Therefore, the aforementioned steps of stopping fuel supply and combustion in two cylinders reduce the risk of wetting the spark plugs 21 in those cylinders, meaning a subsequent engine restart is more likely to be successful. The increased fuel consumption from fuel-rich operation far outweighs the reduced fuel consumption from shutting down half of the cylinders.

[0104] In variations of steps S208 and S210 that can be used in direct injection engines, in particular, a standard fuel mixture (determined by a mapping or lookup table typically used by the engine ECU) can be provided for some cylinders, while a fuel-rich run can be provided for other cylinders to achieve a similar purpose of reducing the risk of wetting on some cylinders, thereby facilitating engine restart.

[0105] In other embodiments, one or both of steps S208 and S210 may be omitted.

[0106] In step S212, the controller 150 determines whether the shut-off timer has reached its predetermined extended operating duration. This duration is set based on a calculation of the engine revolutions required to vent the volume of hydrogen contained in the common fuel rail 52 at its operating pressure (when expanded to atmospheric pressure). Typically, this may correspond to approximately 1 to 3 seconds. In other embodiments, the controller may instead signal the spark plug 21 to initiate ignition and the injector 22 to operate at a predetermined crankshaft revolutions required to empty the common fuel rail 52.

[0107] In other embodiments, controller 150 may monitor the pressure of fuel rail 52 via pressure sensor 53. Once this has been reduced to a threshold pressure at which any remaining hydrogen fuel would not pose a risk of engine damage if it leaked through the injectors (e.g., less than 2.5 bar, optionally less than 2 bar, until reaching or approaching atmospheric pressure). Maintaining positive pressure reduces the risk of debris entering the shared fuel rail 52.

[0108] Then, in step S214, the controller 150 stores a completion shutdown flag in the memory 154, so that... Figure 3 This flag is used in step S108 of the engine start-up process. If the engine stops abnormally, such as due to engine shutdown or emergency stop (via engine isolation switch), the flag will not be set, or a different flag will be set. Therefore, during the start-up process, the controller 150 will instead perform the purging operation of step S110.

[0109] In step S216, the controller 150 then sends a signal to shut down the injector 22 and the coil 23 to stop ignition and shut down the engine 1, and then the process is complete.

[0110] If the engine fails to start and requires repair, a mechanic can use repair tools to perform a drying operation, or the fault code may suggest removing and physically drying any affected spark plugs 21 as needed.

[0111] The above description of one or more embodiments is by way of example only, and it should be understood that various modifications may be made without departing from the scope of protection provided by the appended claims. For example, if the engine is equipped with an electric starter / generator (e.g., a hybrid engine), this can be used to start the engine to purge fuel.

Claims

1. An engine starting system for a hydrogen fuel cell internal combustion engine, the system comprising: Controller; At least one fuel ignition device, communicating with the controller; as well as The hydrogen fuel delivery system communicates with the controller. The system is configured such that, upon receiving an engine start command, the controller is configured to instruct the fuel ignition device to ignite, but not to instruct the fuel supply to begin, and the controller is configured to monitor the output of the fuel ignition device to obtain a signal indicating the generation of a spark.

2. The engine starting system of claim 1, wherein when a spark is detected, the controller is configured to instruct the supply of fuel for combustion in the engine.

3. The engine starting system according to claim 1 or 2, wherein the controller is further configured to determine whether excess hydrogen has been purged from the fuel delivery system of the internal combustion engine before instructing the at least one fuel ignition device to ignite.

4. The engine starting system according to any one of the preceding claims, wherein the controller is further configured to instruct the at least one fuel ignition device to perform a drying operation when it is determined that the ignition of the fuel ignition device has failed.

5. The engine starting system of claim 4, wherein during the fuel ignition device drying operation, the controller sends an ignition signal to the fuel ignition device or each fuel ignition device that is determined to be wet.

6. The engine starting system according to claim 4 or 5, wherein the fuel ignition device drying operation includes starting the engine without supplying fuel.

7. The engine starting system according to any one of claims 4 to 6, wherein during the drying operation, the controller is configured to monitor the output of the fuel ignition device to obtain a signal indicating the generation of a spark.

8. The engine starting system of claim 7, wherein, upon detecting a signal indicating spark generation, the controller is configured to instruct the drying operation to stop and to instruct the supply of fuel to the engine cylinder corresponding to the fuel ignition device.

9. The engine starting system of claim 8, wherein the controller is configured to monitor the combustion of fuel in the cylinder after indicating fuel supply.

10. The engine starting system of claim 9, wherein the controller is configured to instruct to stop supplying fuel to the cylinder and to instruct to generate a spark for the cylinder if combustion is not detected.

11. The engine starting system of claim 10, wherein the controller is configured to instruct the supply of fuel to the cylinder upon detection of a spark in the cylinder.

12. The engine starting system according to claim 3 or any one of claims 4 to 11, which are dependent on claim 3, wherein the controller is configured to determine whether the engine has purged excess hydrogen by confirming whether a previous normal engine shutdown procedure has been completed.

13. The engine starting system according to claim 3 or any one of claims 4 to 12 which are dependent on claim 3, wherein the controller is configured to instruct a hydrogen purging operation if it is determined that the internal combustion engine has not purged excess hydrogen.

14. The engine starting system of claim 13, wherein the controller is configured to instruct the engine to start without instructing the fuel ignition device to purge hydrogen in the engine.

15. The engine starting system of claim 14, wherein the controller is further configured to instruct the hydrogen fuel delivery system not to supply fuel during a purging operation.

16. The engine starting system according to any one of claims 13 to 15, wherein the controller is configured to indicate that the purging operation lasts for a predetermined time or a predetermined number of engine revolutions.

17. The engine starting system according to any one of the preceding claims, wherein the at least one fuel ignition device comprises an ignition coil and a spark plug.

18. The engine starting system according to any one of the preceding claims, wherein the hydrogen fuel delivery system includes at least one fuel injector, the fuel injector optionally being in fluid communication with a common fuel rail.

19. The engine starting system according to any one of the preceding claims, wherein the engine comprises a plurality of cylinders.

20. The engine starting system according to claim 19, which is dependent on claim 8, wherein the controller is configured to instruct the drying operation to be stopped only if a signal indicating spark generation is detected in the fuel ignition device corresponding to each of the plurality of cylinders.

21. A hydrogen fuel cell internal combustion engine, comprising an engine starting system according to any one of the preceding claims.

22. A method for starting a hydrogen fuel cell internal combustion engine, the internal combustion engine including at least one fuel ignition device and a hydrogen fuel delivery system, the method comprising the following steps: a. Upon receiving an engine start command, instruct the fuel ignition device to ignite, but do not instruct the fuel supply to begin; b. Monitor the output of the fuel ignition device to obtain a signal indicating the generation of a spark.

23. The method of claim 22, further comprising step c) after step b): upon detection of a spark, instructing the supply of hydrogen fuel for combustion in the engine.

24. The method according to claim 22 or 23, further comprising step d) after step b): performing a drying operation on the at least one fuel ignition device when it is determined that the ignition of the fuel ignition device has failed.

25. The method according to any one of claims 22 to 24, further comprising step e): determining whether excess hydrogen has been purged from the fuel delivery system of the internal combustion engine before instructing the at least one fuel ignition device to ignite.

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