Fuel injection system and fuel injection method for a vehicle internal combustion engine

Abstract

Disclosed are a fuel injection system and a fuel injection method for an internal combustion engine of a vehicle, in particular, a fuel injection system (45) for an internal combustion engine, comprising: a first fuel injector (50) connected to a high-pressure fuel source (53); a second fuel injector (55) connected to a low-pressure fuel source (57); an intake pre-chamber (60) that receives fuel injected by the fuel injectors; an intake nozzle (65) that receives fuel from the intake pre-chamber and injects the fuel into a combustion chamber (20); a spark plug (70) located inside the pre-chamber and configured to ignite fuel injected by the fuel injectors; and a controller connected to the fuel injectors to control fuel injection into the intake pre-chamber by the first fuel injector and fuel injection into the intake pre-chamber by the second fuel injector in accordance with a requested torque of the internal combustion engine and in accordance with fuel availability at the fuel sources.

Description

Technical Field

[0001] This disclosure generally relates to vehicles having internal combustion engines. In a particular aspect, this disclosure relates to a fuel injection system and fuel injection method for an internal combustion engine in a vehicle. This disclosure is applicable to heavy vehicles, such as trucks, buses, and construction equipment, as well as other vehicle types. Although this disclosure may be described with respect to a particular vehicle, it is not limited to any particular vehicle. Background Technology

[0002] For internal combustion engines fueled by hydrogen, it is known that efficiency and power are enhanced when hydrogen is supplied at high pressures (e.g., above 300 bar), allowing the fuel injected into the combustion chamber to ignite with a diffusion flame. In contrast, injecting premixed hydrogen into the combustion chamber at lower pressures and igniting it with a spark plug results in lower efficiency and also implies the presence of a highly flammable air-hydrogen mixture before ignition. Vehicles using internal combustion engines include pressurized fuel tanks that supply hydrogen to the engine at high pressure when the tank is full. However, as the engine consumes fuel, the fuel pressure in the tank decreases until it drops to values ​​such as below 250 to 300 bar, at which point, at high compression ratios, the highly efficient diffusion flame (CA50) close to maximum efficiency is no longer achieved. CA50 is the crankshaft angle reached when 50% of the injected fuel mass is burned. In this situation, the remaining fuel in the tank becomes unusable. To address this issue, some vehicles include compressors to maintain sufficiently high fuel pressure even when little usable fuel remains in the tank. However, such solutions are costly, take up vehicle space, and reduce the overall efficiency of the vehicle because the compressor also consumes energy. Therefore, this disclosure aims to provide a fuel injection system that achieves high efficiency, empties the fuel tank, and reduces the need for a compressor. Summary of the Invention

[0003] According to a first aspect of this disclosure, a fuel injection system for an internal combustion engine includes: - A first fuel injector, configured to be connected to a high-pressure fuel source. - A second fuel injector, configured to connect to a low-pressure fuel source. - An intake pre-combustion chamber configured to receive fuel injected by the first fuel injector and fuel injected by the second fuel injector. - An intake nozzle configured to receive fuel from the intake pre-combustion chamber and inject the fuel into the combustion chamber of the internal combustion engine. - A spark plug, located inside the pre-combustion chamber and configured to ignite fuel injected by the first fuel injector or the second fuel injector, and - A controller, the connector being connected to the first fuel injector, the second fuel injector and the spark plug, for controlling fuel injection from the first fuel injector to the intake pre-combustion chamber, fuel injection from the second fuel injector to the intake pre-combustion chamber and the spark plug according to the requested torque of the internal combustion engine and according to fuel availability at the high-pressure fuel source and the low-pressure fuel source.

[0004] The first aspect of this disclosure is intended for the efficient use of an internal combustion engine supplied with gaseous fuel, and the exhaust gas fuel tank. Technical advantages may include saving high-pressure fuel from a high-pressure fuel source by using fuel from a low-pressure fuel source when the requested torque is in the low-load range.

[0005] Optionally, in some examples, including at least one preferred example, the controller is configured such that when the requested torque is in a moderate load range and fuel is available at both the high-pressure and low-pressure fuel sources, the ratio of fuel injection from the first fuel injector to fuel injection from the second fuel injector is a function of the requested torque, increasing as the requested torque increases. Technical advantages may include saving high-pressure fuel from the high-pressure fuel source by preferentially prioritizing the low-pressure fuel source over the high-pressure fuel source when the requested torque is in a moderate load range.

[0006] Optionally, in some examples, including at least one preferred example, the controller is configured such that, during control: - When the requested torque is within the high load range and fuel is available at the high-pressure fuel source, the first fuel injector injects the required power amount of fuel, while the second fuel injector either does not inject fuel or injects a pre-burned amount of fuel; and - When the requested torque is in the low load range and fuel is available at the low-pressure fuel source, the second fuel injector injects a power amount of fuel, while the first fuel injector does not inject fuel.

[0007] Technological advantages can include optimizing fuel use in both low-pressure and high-pressure fuel sources to improve efficiency and enabling the venting of air-filled fuel tanks. In fact, when large amounts of fuel are required, i.e., under high loads, using high pressure maximizes efficiency. Conversely, under low loads where less fuel is needed, lower combustion efficiency is tolerated by using low-pressure fuel to power the engine, not only to conserve high-pressure fuel for later use but also to consume low-pressure fuel from the low-pressure fuel source.

[0008] Optionally, in some examples, including at least one preferred example, the controller is configured to inject fuel from the first fuel injector at the end of the compression stroke of the internal combustion engine when the torque request is in the high load range and fuel is available at the high-pressure fuel source. Technical advantages may include optimizing fuel use from the high-pressure fuel source for high efficiency. In fact, when fuel ignition conditions are optimal, injecting high-pressure fuel into the intake pre-combustion chamber ensures that all energy released due to fuel ignition is used to power the engine.

[0009] Optionally, in some examples, including at least one preferred example, the controller is configured such that when the torque request is within the low load range and fuel is available at the low-pressure fuel source, fuel injected by the second fuel injector is injected during the intake stroke of the internal combustion engine or at the beginning of the compression stroke, and the spark plug ignites the fuel at the end of the compression stroke of the internal combustion engine. Technical advantages may include optimizing fuel use from the low-pressure fuel source. In fact, the low-pressure fuel is injected during the intake stroke or at the beginning of the compression stroke, such that the fuel is compressed during the compression stroke to increase the potential energy released when the low-pressure injected fluid is ignited.

[0010] Optionally, in some examples, including at least one preferred example, the fuel injection system further includes several gaseous fuel storage tanks for feeding fuel to the high-pressure fuel source and the low-pressure fuel source. Optionally, in some examples, including at least one preferred example, the fuel injection system includes a fuel distributor connected to the gaseous fuel storage tanks, the high-pressure fuel source, and the low-pressure fuel source for distributing fuel from the gaseous fuel storage tanks to the high-pressure fuel source and the low-pressure fuel source, such that: - Each gaseous fuel storage tank containing gaseous fuel at a pressure exceeding a predetermined pressure threshold is fed fuel to the high-pressure fuel source via the distributor; and - Each gaseous fuel storage tank containing gaseous fuel at a pressure below the predetermined pressure threshold feeds fuel to the low-pressure fuel source via the distributor.

[0011] The technological advantages can include: some fuel tanks can be kept at high pressure while others are emptied, allowing for efficient fuel delivery from the high-pressure source under high loads; while under low loads, prioritizing the emptying of fuel tanks improves vehicle autonomy. Thus, the use of gaseous fuels is optimized in terms of both efficiency and autonomy.

[0012] Optionally, in some examples, including at least one preferred example, the pressure threshold is between 250 bar and 320 bar. Technical advantages may include ensuring that fuel supplied at high pressure can be ignited via a diffusion flame ignition method, thereby achieving maximum combustion efficiency.

[0013] Optionally, in some examples, including at least one preferred example, the gaseous fuel storage tank is a hydrogen storage tank. Technical advantages may include: using a hydrogen fuel tank means that when the tank is full, hydrogen can be stored at a pressure sufficient to achieve efficient combustion (e.g., a diffusion flame) by injection at a first fuel injector without relying on an embedded compressor, although hydrogen requires relatively higher pressure to achieve such efficient combustion compared to other types of fuels. Furthermore, the fuel injection system allows the hydrogen fuel tank to be emptied by injecting low-pressure hydrogen during engine operation.

[0014] According to a second aspect of this disclosure, an internal combustion engine system includes: - As defined above, fuel injection systems, - A combustion chamber, wherein the intake nozzle leads to the combustion chamber for injecting fuel from the intake pre-combustion chamber into the combustion chamber, and - A piston, which is mounted in the combustion chamber and configured to reciprocate relative to the combustion chamber.

[0015] A second aspect of this disclosure is intended for the efficient use of an internal combustion engine supplied with gaseous fuel, in conjunction with an air-fuel storage tank. Technical advantages may include saving pressure from a high-pressure fuel source by using fuel from a low-pressure fuel source when the requested torque is in the low-load range.

[0016] According to a third aspect of this disclosure, a vehicle includes an internal combustion engine system as defined above. This third aspect of the disclosure is intended for efficient use of an internal combustion engine supplied with gaseous fuel and an exhaust gas fuel tank. Technical advantages may include saving pressure from a high-pressure fuel source by using fuel from a low-pressure fuel source when the requested torque is in the low-load range.

[0017] According to a fourth aspect of this disclosure, a fuel injection method implemented by a fuel injection system as defined above includes controlling, via a controller, fuel injection from a first fuel injector to the intake pre-combustion chamber and fuel injection from a second fuel injector to the intake pre-combustion chamber, as well as fuel ignition by a spark plug, based on a requested torque of the internal combustion engine and fuel availability at the high-pressure and low-pressure fuel sources. The fourth aspect of this disclosure is intended for efficient use of an internal combustion engine supplied with gaseous fuel, with the exhaust gas fuel reservoir being displaced. Technical advantages may include saving pressure from the high-pressure fuel source by using fuel from the low-pressure fuel source when the requested torque is in the low-load range.

[0018] Optionally, in some examples, including at least one preferred example, the control includes, when the requested torque is in a medium load range and fuel is available at both the high-pressure and low-pressure fuel sources, the ratio of fuel injection from the first fuel injector to fuel injection from the second fuel injector is a function of the requested torque, with the ratio increasing as the requested torque increases. Technical advantages may include saving pressure from the high-pressure fuel source by replacing the high-pressure fuel source with the low-pressure fuel source when the requested torque is in a medium load range.

[0019] Optionally, in some examples, including at least one preferred example, the control includes: - When the requested torque is within the high load range and fuel is available at the high-pressure fuel source, the first fuel injector injects the required power amount of fuel, while the second fuel injector either does not inject fuel or injects the required pre-burn amount of fuel; and When the requested torque is in the low load range and fuel is available at the low-pressure fuel source, the second fuel injector injects that amount of fuel, while the first fuel injector does not inject fuel.

[0020] Technological advantages can include optimizing fuel use in both low-pressure and high-pressure fuel sources to improve efficiency and enabling the venting of air-filled fuel tanks. In fact, when large amounts of fuel are required, i.e., under high loads, using high pressure maximizes efficiency. Conversely, under low loads where less fuel is needed, lower combustion efficiency is tolerated by using low-pressure fuel to power the engine, not only to conserve high-pressure fuel for later use but also to consume low-pressure fuel from the low-pressure fuel source.

[0021] Optionally, in some examples, including at least one preferred example, control includes injecting fuel injected by the first fuel injector at the end of the compression stroke of the internal combustion engine when the torque request is in the high load range and fuel is available at the high-pressure fuel source. Technical advantages may include optimizing fuel use from the high-pressure fuel source for high efficiency. In fact, when fuel ignition conditions are optimal, injecting high-pressure fuel into the intake pre-combustion chamber ensures that all energy released due to fuel ignition is used to power the engine.

[0022] Optionally, in some examples, including at least one preferred example, control includes injecting fuel from the second fuel injector during the intake stroke of the internal combustion engine or at the start of the compression stroke when the torque request is in the low load range and fuel is available at the low-pressure fuel source, and the spark plug ignites the fuel at the end of the compression stroke of the internal combustion engine. Technical advantages may include optimizing fuel use from the low-pressure fuel source. In fact, the low-pressure fuel is injected during the intake stroke or at the start of the compression stroke, such that the fuel is compressed during the compression stroke to increase the potential energy released when the low-pressure injected fluid is ignited.

[0023] Optionally, in some examples, including at least one preferred example, the method includes distributing fuel from the gaseous fuel tank to the high-pressure fuel source and the low-pressure fuel source via the dispenser.

[0024] - Each gaseous fuel storage tank containing gaseous fuel at a pressure exceeding the predetermined pressure threshold is fed fuel to the high-pressure fuel source via the distributor; and

[0025] - Each gaseous fuel storage tank containing gaseous fuel at a pressure below the predetermined pressure threshold feeds fuel to the low-pressure fuel source via the distributor.

[0026] The technological advantages can include: some fuel tanks can be kept at high pressure while others are emptied, allowing for efficient fuel delivery from the high-pressure source under high loads; while under low loads, prioritizing the emptying of fuel tanks improves vehicle autonomy. Thus, the use of gaseous fuels is optimized in terms of both efficiency and autonomy.

[0027] The disclosed aspects, examples, and / or appended claims may be suitably combined with each other, as will be apparent to any person skilled in the art. Additional features and advantages are disclosed in the following description, claims, and drawings, and will be apparent in part to those skilled in the art or will be recognized by practicing this disclosure as described herein. Attached Figure Description

[0028] The examples are described in more detail below with reference to the accompanying drawings.

[0029] Figure 1 A vehicle according to the present invention is depicted.

[0030] Figure 2 yes Figure 1 A schematic diagram of the combustion chamber, piston, and fuel injection system of an internal combustion engine in a vehicle.

[0031] Figure 3 yes Figure 2 A schematic diagram of the fuel injection system. Detailed Implementation

[0032] The detailed description set forth below provides information and examples of the disclosed technology in sufficient detail to enable those skilled in the art to practice this disclosure.

[0033] Figure 1 A vehicle 1 according to an embodiment of the present invention is depicted, the vehicle including a frame 2, a cab 3, wheels 4, a cargo compartment 5, and a transmission system 7.

[0034] The cab 3 is supported by the frame 2 and is located at the front of the vehicle 1. The vehicle 1 can be driven by a driver. The driver inside the cab 3 controls the vehicle 1.

[0035] The cab 3 includes a pedal 11. When the driver presses the pedal 11 with his foot, the pedal 11 tilts to different positions.

[0036] Products can be stored in cargo compartment 5 for transport from one location to another. Cargo compartment 5 is supported by frame 2 and is located at the rear of vehicle 1. In a variant not shown, cargo compartment 5 is supported by a second frame hooked to frame 2.

[0037] Wheels 4 are mounted on the frame 2 and are configured to rotate so that vehicle 1 can move on road 6.

[0038] The transmission system 7 includes an internal combustion engine 15. The internal combustion engine 15 includes an output shaft (not shown) that rotates when the internal combustion engine 15 is actuated. The rotation of the output shaft causes the wheels 4 to rotate.

[0039] The transmission system 7 provides propulsion to the vehicle 1 to propel the vehicle 1. The propulsion is the result of the transmission system 7 mechanically converting the torque provided by the internal combustion engine 15 to the output shaft.

[0040] The driver requests the desired thrust by pressing pedal 11. In other words, the driver presses pedal 11 to request the desired torque from the internal combustion engine 15.

[0041] The internal combustion engine 15 includes a combustion chamber 20 configured to receive fuel, preferably gaseous fuel, preferably gaseous hydrogen. The combustion chamber 20 includes an air inlet 23 connecting it to the outside. The air inlet 23 is configured to supply air to the combustion chamber 20 and discharge combustion products to the outside of the combustion chamber 20. The internal combustion engine 15 also includes a piston 25 mounted in the combustion chamber 20 and configured to reciprocate relative to the combustion chamber 20. More precisely, the piston 25 translates relative to the combustion chamber 20 between an upper end 30 and a lower end 35 of the combustion chamber 20. The position of the piston 25 within the combustion chamber 20 defines a volume 40. More precisely, the volume 40 is defined between the upper end 30 and the piston 25.

[0042] During operation of the internal combustion engine 15, the internal combustion engine 15 performs a four-stroke cycle in a repetitive manner. This cycle includes an intake stroke, in which the piston 25 translates towards the bottom 35 within the combustion chamber 20, increasing the volume 40 and decreasing the pressure within the volume 40, causing fuel to be drawn into the volume 40. The cycle then includes a compression stroke, in which the piston 25 moves towards the top 40, decreasing the volume 40 and increasing the pressure within the volume 40. The cycle then includes an expansion stroke, in which the piston 25 translates towards the bottom 35 due to fuel combustion. The cycle then includes an exhaust stroke, in which the piston translates towards the top 30, and the products of fuel combustion are discharged from the combustion chamber 20 through the intake port 23.

[0043] The internal combustion engine 15 includes a fuel injection system 45. The fuel injection system 45 includes: a first fuel injector 50 configured to be connected to a high-pressure fuel source 53 of the fuel injection system 45; a second fuel injector 55 configured to be connected to a low-pressure fuel source 57 of the fuel injection system 45; and an intake pre-combustion chamber 60 configured to receive fuel injected by the first fuel injector 50 and fuel injected by the second fuel injector 55.

[0044] The fuel injection system 45 includes an intake nozzle 65 configured to receive fuel from the intake pre-combustion chamber 60 and inject the fuel into the combustion chamber 20. In other words, the intake nozzle fluidly connects the intake pre-combustion chamber 60 and the combustion chamber 20.

[0045] The fuel injection system 45 includes a spark plug 70 located inside the intake pre-combustion chamber 60, which is configured to ignite fuel injected by a first fuel injector 50 or a second fuel injector 55 via plasma discharge.

[0046] Advantageously, the fuel injection system 45 includes several gaseous fuel storage tanks 75. In this example, the fuel injection system 45 includes five gaseous fuel storage tanks 75. The gaseous fuel storage tanks 75 are filled with pressurized gaseous fuel. Advantageously, the gaseous fuel storage tanks 75 are hydrogen storage tanks.

[0047] Each of the gaseous fuel tanks 75 is connected to a high-pressure fuel source 53 and a low-pressure fuel source 57 to feed fuel to either the high-pressure fuel source 53 or the low-pressure fuel source 57 based on the available fuel pressure in the considered fuel tank 75. More precisely, the fuel injection system 45 includes a distributor 80 configured to distribute fuel from the gaseous fuel tank 75 to the high-pressure fuel source 53 and the low-pressure fuel source 57 according to the fuel pressure in each gaseous fuel tank 75. In other words, each gaseous fuel tank 75 containing gaseous fuel at a pressure exceeding a predetermined pressure threshold feeds fuel to the high-pressure fuel source 53 via the distributor 80, while each gaseous fuel tank 75 containing gaseous fuel at a pressure below the predetermined pressure threshold feeds fuel to the low-pressure fuel source 57 via the distributor 80. During use, if the pressure in a single tank within tank 75 drops (e.g., due to the consumption of fuel contained therein), tank 75 may sequentially feed fuel to high-pressure fuel source 53 and low-pressure fuel source 57. When the pressure in tank 75 again exceeds a threshold (e.g., by refueling vehicle 1), tank 75 feeding fuel to low-pressure fuel source 57 will again feed fuel to high-pressure fuel source 53. Distributor 80 performs the function of directing fuel from tank 75 to sources 53 and 57. For this purpose, for example, distributor 80 includes one or more valves for each tank 75, which switch between the two sources 53 and 57 based on the fuel pressure value in tank 75 relative to a pressure threshold.

[0048] In a variant not shown, a pressure regulator is installed downstream of the distributor 80 to control the fuel pressure of the first fuel injector 50, and another pressure regulator is installed for the second fuel injector 55.

[0049] Advantageously, the pressure threshold is between 250 bar and 320 bar.

[0050] The fuel injection system 75 includes a controller 85 connected to the first fuel injector 50, the second fuel injector 55, and the spark plug 70. The controller 85 is configured to control the fuel injection system 75. Generally, the controller 85 may be a computer or computing system, or a similar electronic computing device, adapted to manipulate parameters represented as physical quantities (such as electronic quantities) within the computing system registers and / or memory, and / or to transform such parameters into other parameters similarly represented as physical quantities within the computing system memory, registers, or other such information storage, transmission, or display devices.

[0051] The controller 85 preferably includes a processing unit. The term "processing unit" as disclosed herein should be broadly interpreted to include any kind of electronic device having data processing circuitry capable of performing various data processing operations, including, for example, computer processing devices operatively connected to a computer-readable medium: such as digital signal processors (DSPs), microcontrollers, field-programmable gate arrays (FPGAs), and application-specific integrated circuits (ASICs).

[0052] It may contain a single processor or multiple processors, which may be located in the same geographic area or at least partially in different areas, and may be able to communicate with each other.

[0053] A computer-readable medium is a medium that can be read by a processing unit. A computer-readable medium is a medium suitable for storing electronic instructions and capable of being connected to a computer system bus.

[0054] Such computer-readable storage media are, for example, disks, floppy disks, optical disks, CD-ROMs, magneto-optical disks, read-only memory (ROM), random access memory (RAM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic cards or optical cards, or any other medium suitable for storing electronic instructions and capable of being connected to a computer system bus.

[0055] A computer program is stored in a computer-readable storage medium. A computer program includes one or more stored sequences of program instructions.

[0056] A computer program can be loaded into the processing unit and is adapted to execute the charging method while the processing unit is running the computer program. The controller 85 is configured to execute a fuel injection method. The fuel injection method includes controlling fuel injection from the first fuel injector 50 to the intake pre-combustion chamber 60, fuel injection from the second fuel injector 55, and fuel ignition from the spark plug to the intake pre-combustion chamber 60 based on the requested torque of the internal combustion engine 15 and the fuel availability at the high-pressure fuel source 53 and the low-pressure fuel source 57. The fuel availability at the high-pressure fuel source 53 and the low-pressure fuel source 57 depends on the fuel pressure in the gaseous fuel reservoirs 75. At the start of the journey of the vehicle 1, all gaseous fuel reservoirs 75 are full of fuel, and the fuel pressure in each gaseous fuel reservoir 75 is above a pressure threshold, such that the distributor 80 only distributes fuel to the high-pressure fuel source 53, without distributing fuel from the gaseous fuel reservoirs 80 to the low-pressure fuel source 57, and no fuel is available at the low-pressure fuel source 57. During the stroke, fuel from gaseous fuel tank 75 is injected into the intake pre-combustion chamber 60, and the fuel pressure in one or more gaseous fuel tanks 75 decreases until the fuel pressure in one or more fuel tanks 75 drops below a pressure threshold. At this point, distributor 80 feeds fuel from tank 75 at high pressure to high-pressure fuel source 53, while simultaneously feeding fuel from tank 75 whose fuel pressure has dropped below the threshold to low-pressure fuel source 57. During the stroke, the fuel pressure in each tank 75 may drop below the threshold. In this case, distributor feeds fuel from all tanks 75 to low-pressure fuel source 57, where fuel is available, while no fuel is available at high-pressure fuel source 53. In other words, the pressure in each gaseous fuel tank 75 is proportional to the fuel level in the gaseous fuel tank 75, and the fuel availability at high-pressure fuel source 53 and low-pressure fuel source 57 depends on the fuel level in the gaseous fuel tank 75.

[0057] Advantageously, when the requested torque is in the high-load range and fuel is available at the high-pressure fuel source 53, the first fuel injector 50 injects power-equal amounts of fuel, while the second fuel injector 55 either does not inject fuel or injects a pre-burn amount of fuel. In this example, the pre-burn amount is less than 50%, preferably less than 30%, and more preferably less than 10% of the total fuel amount injected per cycle, which is the sum of the power amount and the pre-burn amount. In this case, when no fuel is available at the low-pressure source 57, the second fuel injector 55 does not inject fuel. In this case, when fuel is available at the low-pressure source 57, the second fuel injector 55 either does not inject fuel or injects a pre-burn amount of fuel. The pre-burn amount is less than the power amount. The pre-burn amount is only used to ignite the power-equal amounts of fuel injected subsequently. In contrast, the power-equal amounts of fuel are suitable for powering the internal combustion engine 15, particularly for driving the piston 25 during the expansion stroke.

[0058] Advantageously, during the intake stroke or at the start of the compression stroke of the internal combustion engine 15, if fuel is available at the low-pressure fuel source 57, the second fuel injector 55 injects a pre-burned amount of fuel into the intake pre-combustion chamber 60; or if no fuel is available at the low-pressure fuel source 57, the first fuel injector 50 injects a pre-burned amount of fuel into the intake pre-combustion chamber. At the end of the compression stroke, the fuel in the intake pre-combustion chamber 60 is ignited by the spark plug 70, and the first fuel injector 50 injects a power-equal amount of fuel into the intake pre-combustion chamber 60 at high pressure. The fuel injected by the first fuel injector 50 is at high pressure, and due to the ignition of the pre-burned amount of fuel injected during the intake stroke or at the start of the compression stroke, and due to the compression stroke, the conditions in the intake pre-combustion chamber 60 are mature enough to ignite the power-equal amount of fuel injected by the first fuel injector 50 at the end of the compression stroke. The ignition of the power-equal amount of fuel injected by the first fuel injector 50 at the end of the compression stroke releases energy and drives the expansion stroke. In other words, the pre-burned fuel injected during the intake stroke or at the beginning of the compression stroke is only intended to ignite the power amount of fuel injected at high pressure at the end of the compression stroke.

[0059] Advantageously, when the requested torque is in the low load range and fuel is available at the second fuel source 57, the second fuel injector 55 injects a power amount of fuel, while the first fuel injector 50 does not inject fuel.

[0060] More precisely, during the intake stroke or at the start of the compression stroke of the internal combustion engine 15, the second fuel injector 55 injects a power-equal amount of fuel into the intake pre-combustion chamber 60. Furthermore, during the intake stroke, air is drawn into the combustion chamber 20 through the intake port 23. The intake nozzle 65 allows airflow from both the combustion chamber 20 and the intake pre-combustion chamber 60, allowing the air to mix with the fuel in the intake pre-combustion chamber 60. At the end of the compression stroke, the fuel mixed with air in the intake pre-combustion chamber 60 is ignited by the spark plug 70, releasing energy to drive the expansion stroke. In other words, at the end of the compression stroke, the first fuel injector 50 does not inject fuel, and the expansion stroke is driven primarily by the energy released from the ignition of fuel injected from the second fuel injector 55, but also to a lesser extent by the volumetric gas flow in the first injector. Less energy is released compared to fuel injected from the first fuel injector 50, but this is sufficient to drive the internal combustion engine 15 with torque over low loads.

[0061] Because of this invention, fuel is saved in the high-pressure fuel source 53 when the requested torque is in the low load range. In other words, when the requested torque is in the low load range, gaseous fuel tanks 75 with pressure exceeding the pressure threshold are not used, and the pressure in these gaseous fuel tanks 75 is saved. Furthermore, this invention enables the use of fuel in the gaseous fuel tanks 75 when the pressure is below the pressure threshold, and enables full utilization of the fuel filled in the gaseous fuel tanks 75 at the start of the stroke.

[0062] When the requested torque is in the low load range and no fuel is available at the low-pressure fuel source 57, the controller 85 controls the fuel injection system 45 in the same way as when the torque is in the high load range and fuel is available at the high-pressure fuel source 53, but the first fuel injector 50 injects less fuel at the end of the compression stroke to release less energy.

[0063] Advantageously, when the requested torque is within the medium load range and fuel is available at both the high-pressure fuel source 53 and the low-pressure fuel source 57, the ratio of fuel injection from the first fuel injector 50 to fuel injection from the second fuel injector 55 is a function of the requested torque; the higher the requested torque, the higher this ratio. More specifically, during the intake stroke or at the beginning of the compression stroke, the second fuel injector 55 injects a power amount of fuel, which is mixed with air. Then, at the end of the compression stroke, the fuel is ignited to release energy to drive the expansion stroke, and at the end of the compression stroke, another power amount of fuel is injected from the first fuel injector 50, which automatically ignites and releases energy to drive the expansion stroke. In other words, when the requested torque is within the medium load range, the energy used to drive the expansion stroke is released by igniting the fuel injected by the second fuel injector 55 and the fuel injected by the first fuel injector 50, and the released energy depends on the ratio.

[0064] Due to this invention, fuel is saved in the high-pressure fuel source 53 when the requested torque is within the medium load range. In other words, when the requested torque is within the medium load range, the gaseous fuel tank 75 with pressure above the pressure threshold is used less frequently and is replaced by the gaseous fuel tank 75 with pressure below the pressure threshold, thus saving pressure in the gaseous fuel tank 75 with pressure above the pressure threshold. Furthermore, this invention allows the use of fuel in the gaseous fuel tank 75 when the pressure is below the pressure threshold, and allows full utilization of the fuel filled in the gaseous fuel tank 75 at the start of the journey.

[0065] When the requested torque is in the medium load range and no fuel is available at the low-pressure fuel source 57, the controller 85 controls the fuel injection system 45 in the same way as when the torque is in the high load range and fuel is available at the high-pressure fuel source 53, but the first fuel injector 50 injects less fuel at the end of the compression stroke to release less energy.

[0066] When no fuel is available at the high-pressure fuel source 53 and the requested torque is in the medium or high load range, the controller 57 controls the fuel injection system 45 in the same way as when the torque is in the low load range and fuel is available at the low-pressure source 57. In other words, the controller 57 controls the fuel injection system 45 in a degraded mode, but allows the use of fuel that is still available at the low-pressure fuel source 57.

[0067] Advantageously, the method includes distributing fuel from a gaseous fuel tank 75 to a high-pressure fuel source 53 and a low-pressure fuel source 57 via a distributor 80, such that each gaseous fuel tank 75 containing gaseous fuel with a pressure exceeding a predetermined pressure threshold feeds fuel to the high-pressure fuel source 53 via the distributor 80; while each gaseous fuel tank 75 containing gaseous fuel with a pressure below the predetermined pressure threshold feeds fuel to the low-pressure fuel source 57 via the distributor 80. More precisely, the controller 85 commands the distributor 80 to feed fuel to the high-pressure fuel source 53 from the same gaseous fuel tank 75 until the pressure in that gaseous fuel tank 75 drops below the pressure threshold. Furthermore, the controller 85 commands the distributor 80 to feed fuel to the low-pressure fuel source 57 from the same gaseous fuel tank 75 until the gaseous fuel tank 75 is empty. In other words, the gaseous fuel tank 75 is used to feed fuel to fuel sources 53 and 57 in sequence.

[0068] In a variant not shown, a pressure regulator is installed from the distributor to the first injector, and another pressure regulator, set to a lower pressure, is installed from the distributor to the second injector. The purpose of these pressure regulators is to simplify injector control. The regulators can use a fixed outlet pressure or an outlet pressure controllable via controller 85.

[0069] In variants not shown, controller 85 controls fuel injection from the first fuel injector 50 to the intake pre-combustion chamber 60, fuel injection from the second fuel injector 55 to the intake pre-combustion chamber 60, and plasma discharge from the spark plug 70 based on one or more quantities associated with the internal combustion engine 15 and / or the road 6.

[0070] Example 1: A fuel injection system 45 for an internal combustion engine 15, the fuel injection system 45 comprising: - A first fuel injector 50, which is configured to be connected to a high-pressure fuel source 53. - A second fuel injector 55, which is configured to be connected to a low-pressure fuel source 57. - An intake pre-combustion chamber 60, configured to receive fuel injected by the first fuel injector 50 and fuel injected by the second fuel injector 55. - An intake nozzle 65, configured to receive fuel from the intake pre-combustion chamber 60 and inject the fuel into the combustion chamber 20 of the internal combustion engine 15. - Spark plug 70, located inside the pre-combustion chamber 60 and configured to ignite fuel injected by the first fuel injector 50 or the second fuel injector 55, and - Controller 85, the connector being connected to the first fuel injector 50, the second fuel injector 55 and the spark plug 70, for controlling fuel injection from the first fuel injector 50 to the intake pre-combustion chamber 60, fuel injection from the second fuel injector 55 to the intake pre-combustion chamber 60 and the spark plug 70 according to the requested torque of the internal combustion engine 15 and according to the fuel availability at the high-pressure fuel source 53 and the low-pressure fuel source 57.

[0071] Example 2: A fuel injection system 45 as described in Example 1, wherein, in control, the controller 85 is configured such that when the requested torque is in a medium load range and fuel is available at the high-pressure fuel source 53 and the low-pressure fuel source 57, the ratio of fuel injection from the first fuel injector 50 to fuel injection from the second fuel injector 55 is a function of the requested torque, and the higher the requested torque, the higher the ratio.

[0072] Example 3: A fuel injection system 45 as described in any one of Examples 1 or 2, wherein, in control, the controller 85 is configured such that: - When the requested torque is within the high load range and fuel is available at the high-pressure fuel source 53, the first fuel injector 50 injects fuel at the power level, while the second fuel injector 55 either does not inject fuel or injects pre-burned fuel; and When the requested torque is in the low load range and fuel is available at the low-pressure fuel source 57, the second fuel injector 55 injects a power amount of fuel, while the first fuel injector 50 does not inject fuel.

[0073] Example 4: A fuel injection system 45 as described in Example 3, wherein, in control, the controller 85 is configured such that when the torque request is in the high load range and fuel is available at the high pressure fuel source 53, fuel injected by the first fuel injector 50 is injected at the end of the compression stroke of the internal combustion engine 15.

[0074] Example 5: A fuel injection system 45 as described in any one of Examples 3 or 4, wherein, in control, the controller 85 is configured such that when the torque request is in the low load range and fuel is available at the low-pressure fuel source 57, fuel injected by the second fuel injector 55 is injected during the intake stroke of the internal combustion engine 15 or at the beginning of the compression stroke, and the spark plug 70 ignites the fuel at the end of the compression stroke of the internal combustion engine 15.

[0075] Example 6: A fuel injection system 45 as described in any of the preceding examples, wherein the fuel injection system 45 further includes several gaseous fuel storage tanks 75 for feeding fuel to the high-pressure fuel source 53 and the low-pressure fuel source 57.

[0076] Example 7: A fuel injection system 45 as described in Example 6, wherein the fuel injection system 75 includes a fuel distributor 80 connected to the gaseous fuel tank 75, the high-pressure fuel source 53, and the low-pressure fuel source 57 for distributing fuel from the gaseous fuel tank 75 to the high-pressure fuel source 53 and the low-pressure fuel source 57, such that: - Each gaseous fuel storage tank 75 containing gaseous fuel at a pressure exceeding a predetermined pressure threshold is fed fuel to the high-pressure fuel source 53 via the distributor 80; and - Each gaseous fuel storage tank 75 containing gaseous fuel at a pressure below the predetermined pressure threshold feeds fuel to the low-pressure fuel source 57 via the distributor 80.

[0077] Example 8: A fuel injection system 45 as described in any one of Examples 6 or 7, wherein the pressure threshold is between 250 bar and 320 bar.

[0078] Example 9: A fuel injection system 45 as described in any one of Examples 6 to 8, wherein the gaseous fuel storage tank 75 is a hydrogen storage tank.

[0079] Example 10: An internal combustion engine 15, comprising: - Fuel injection system 45 according to any one of the foregoing examples, - Combustion chamber 20, wherein the intake nozzle 65 extends into the combustion chamber 20 for injecting fuel from the intake pre-combustion chamber 60 into the combustion chamber 20, and - Piston 25, which is mounted in the combustion chamber 20 and configured to reciprocate relative to the combustion chamber 20.

[0080] Example 11: A vehicle 1 that includes an internal combustion engine 15 as described in Example 10.

[0081] Example 12: A fuel injection method implemented by a fuel injection system 45 as described in any one of Examples 1 to 9, the fuel injection method comprising controlling, via a controller 85, fuel injection from the first fuel injector 50 to the intake pre-combustion chamber 60 and fuel injection from the second fuel injector 55 to the intake pre-combustion chamber 60, and fuel ignition of the spark plug 70, based on the requested torque of the internal combustion engine 15 and the fuel availability at the high-pressure source 53 and the low-pressure fuel source 57.

[0082] Example 13: A fuel injection method as described in Example 12, wherein the fuel injection system 45 is a fuel injection system according to any one of Examples 2 to 5, and wherein the control includes, when the requested torque is in a medium load range and fuel is available at the high-pressure fuel source 53 and the low-pressure fuel source 57, the ratio of fuel injection from the first fuel injector 50 to fuel injection from the second fuel injector 55 is a function of the requested torque, and the higher the requested torque, the higher the ratio.

[0083] Example 14: A fuel injection method as described in any one of Examples 12 or 13, wherein the fuel injection system 45 is a fuel injection system according to any one of Examples 3 to 5, and wherein control includes: - When the requested torque is within the high load range and fuel is available at the high-pressure fuel source 53, the first fuel injector 50 injects fuel at the power level, while the second fuel injector 55 either does not inject fuel or injects pre-burned fuel; and When the requested torque is in the low load range and fuel is available at the low-pressure fuel source 57, the second fuel injector 55 injects a power amount of fuel, while the first fuel injector 50 does not inject fuel.

[0084] Example 15: A fuel injection method as described in Example 14, wherein the fuel injection system 45 is a fuel injection system according to any one of Examples 4 or 5, and wherein control includes injecting fuel injected by the first fuel injector 50 at the end of the compression stroke of the internal combustion engine 15 when the torque request is in the high load range and fuel is available at the high pressure fuel source 53.

[0085] Example 16: A fuel injection method as described in any one of Examples 14 or 15, wherein the fuel injection system 45 is a fuel injection system according to any one of Examples 5 to 9, and wherein control includes injecting fuel injected by the second fuel injector 55 during the intake stroke of the internal combustion engine 15 or at the beginning of the compression stroke when the torque request is in the low load range and fuel is available at the low-pressure fuel source 57, and the spark plug 70 ignites the fuel at the end of the compression stroke of the internal combustion engine 15.

[0086] Example 17: A fuel injection method as described in any one of Examples 12 to 16, wherein the fuel injection system 45 is the fuel injection system according to Example 7, wherein the method includes distributing fuel from the gaseous fuel tank 75 to the high-pressure fuel source 53 and the low-pressure fuel source 57 via the distributor 80, such that: - Each gaseous fuel storage tank 75 containing gaseous fuel at a pressure exceeding a predetermined pressure threshold is fed fuel to the high-pressure fuel source 53 via the distributor 80; and - Each gaseous fuel storage tank 75 containing gaseous fuel at a pressure below the predetermined pressure threshold feeds fuel to the low-pressure fuel source 57 via the distributor 80.

[0087] The terminology used herein is for descriptive purposes only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” are intended to also include the plural forms. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. It should also be understood that the terms “comprising” and / or “including”, when used herein, indicate the presence of the stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0088] It should be understood that although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0089] In this document, relative terms such as “below,” “above,” “upper,” “lower,” “horizontal,” or “vertical” may be used to describe the relationship between one element and another, as illustrated in the figures. It should be understood that these terms, along with those discussed above, are intended to cover different device orientations in addition to those depicted in the figures. It should be understood that when an element is referred to as “connected” or “coupled” to another element, the element may be directly connected or coupled to the other element, or there may be intermediate elements present. In contrast, when an element is referred to as “directly connected” or “directly coupled” to another element, there are no intermediate elements present.

[0090] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that, unless expressly defined herein, terms used herein shall be interpreted as having the same meaning as they have in the context of this specification and the relevant field, and not in an idealized or overly formal sense.

[0091] It should be understood that this disclosure is not limited to the aspects described above and shown in the accompanying drawings; rather, those skilled in the art will recognize that many changes and modifications can be made within the scope of this disclosure and the appended claims. Aspects have been disclosed in the drawings and description for illustrative purposes only and not for limiting purposes, and the scope of this disclosure is set forth in the appended claims.

Claims

1. A fuel injection system (45) for an internal combustion engine (15), the fuel injection system (45) comprising: - A first fuel injector (50), configured to be connected to a high-pressure fuel source (53), - A second fuel injector (55), configured to be connected to a low-pressure fuel source (57), - An intake pre-combustion chamber (60), configured to receive fuel injected by the first fuel injector (50) and fuel injected by the second fuel injector (55). - An intake nozzle (65) configured to receive fuel from the intake pre-combustion chamber (60) and inject the fuel into the combustion chamber (20) of the internal combustion engine (15). - A spark plug (70), located inside the pre-combustion chamber (60) and configured to ignite fuel injected by the first fuel injector (50) or the second fuel injector (55), and - A controller (85), the connector being connected to the first fuel injector (50), the second fuel injector (55), and the spark plug (70), for controlling fuel injection from the first fuel injector (50) to the intake pre-combustion chamber (60), fuel injection from the second fuel injector (55) to the intake pre-combustion chamber (60), and the spark plug (70) according to the requested torque of the internal combustion engine (15) and according to the fuel availability at the high-pressure fuel source (53) and the low-pressure fuel source (57).

2. The fuel injection system (45) according to claim 1, wherein, in control mode, the controller (85) is configured such that: - When the requested torque is in the high load range and fuel is available at the high-pressure fuel source (53), the first fuel injector (50) injects a power amount of fuel, while the second fuel injector (55) injects no fuel or injects a pre-burn amount of fuel; and When the requested torque is in the low load range and fuel is available at the low-pressure fuel source (57), the second fuel injector (55) injects a power amount of fuel, while the first fuel injector (50) does not inject fuel.

3. The fuel injection system (45) according to claim 2, wherein, in control, the controller (85) is configured such that when the torque request is in the high load range and fuel is available at the high pressure fuel source (53), fuel injected by the first fuel injector (50) is injected at the end of the compression stroke of the internal combustion engine (15).

4. The fuel injection system (45) according to any one of claims 2 or 3, wherein, in control, the controller (85) is configured such that when the torque request is in the low load range and fuel is available at the low-pressure fuel source (57), the fuel injected by the second fuel injector (55) is injected during the intake stroke of the internal combustion engine (15) or at the beginning of the compression stroke, and the spark plug (70) ignites the fuel at the end of the compression stroke of the internal combustion engine (15).

5. The fuel injection system (45) according to any one of the preceding claims, wherein the fuel injection system (45) further comprises several gaseous fuel storage tanks (75) for feeding fuel to the high-pressure fuel source (53) and the low-pressure fuel source (57).

6. The fuel injection system (45) according to claim 5, wherein the fuel injection system (75) includes a fuel distributor (80) connected to the gaseous fuel tank (75), the high-pressure fuel source (53), and the low-pressure fuel source (57) for distributing fuel from the gaseous fuel tank (75) to the high-pressure fuel source (53) and the low-pressure fuel source (57), such that: - Each of the gaseous fuel storage tanks (75) containing gaseous fuel at a pressure exceeding a predetermined pressure threshold feeds fuel to the high-pressure fuel source (53) via the distributor (80); and - Each gaseous fuel tank (75) containing gaseous fuel at a pressure below the predetermined pressure threshold feeds fuel to the low-pressure fuel source (57) via the distributor (80).

7. The fuel injection system (45) according to any one of claims 5 or 6, wherein the pressure threshold is between 250 bar and 320 bar.

8. An internal combustion engine (15) comprising: - The fuel injection system (45) according to any one of the preceding claims, - Combustion chamber (20), wherein the intake nozzle (65) leads to the combustion chamber (20) for injecting fuel from the intake pre-combustion chamber (60) into the combustion chamber (20), and - Piston (25), which is mounted in the combustion chamber (20) and configured to reciprocate relative to the combustion chamber (20).

9. A vehicle (1) comprising an internal combustion engine (15) according to claim 8.

10. A fuel injection method implemented by a fuel injection system (45) according to any one of claims 1 to 7, the fuel injection method comprising, by means of a controller (85), controlling fuel injection from the first fuel injector (50) to the intake pre-combustion chamber (60) and fuel injection from the second fuel injector (55) to the intake pre-combustion chamber (60) and fuel ignition of the spark plug (70) according to a requested torque of the internal combustion engine (15) and fuel availability at the high-pressure source (53) and the low-pressure fuel source (57).

11. The fuel injection method according to claim 10, wherein the control includes, when the requested torque is in a medium load range and fuel is available at the high-pressure fuel source (53) and the low-pressure fuel source (57), the ratio of the fuel injection of the first fuel injector (50) to the fuel injection of the second fuel injector (55) is a function of the requested torque, and the higher the requested torque, the higher the ratio.

12. The fuel injection method according to any one of claims 10 or 11, wherein the fuel injection system (45) is the fuel injection system according to any one of claims 2 to 4, and wherein control includes: - When the requested torque is in the high load range and fuel is available at the high-pressure fuel source (53), the first fuel injector (50) injects the required amount of fuel, while the second fuel injector (55) either does not inject fuel or injects the required amount of pre-burned fuel; and When the requested torque is in the low load range and fuel is available at the low-pressure fuel source (57), the second fuel injector (55) injects the required amount of fuel, while the first fuel injector (50) does not inject fuel.

13. The fuel injection method according to claim 12, wherein the fuel injection system (45) is the fuel injection system according to any one of claims 3 or 4, and wherein control includes injecting the fuel injected by the first fuel injector (50) at the end of the compression stroke of the internal combustion engine (15) when the torque request is in the high load range and fuel is available at the high pressure fuel source (53).

14. The fuel injection method according to any one of claims 12 or 13, wherein the fuel injection system (45) is the fuel injection system according to claim 4, and wherein control includes injecting the fuel injected by the second fuel injector (55) during the intake stroke of the internal combustion engine (15) or at the beginning of the compression stroke when the torque request is in the low load range and fuel is available at the low-pressure fuel source (57), and the spark plug (70) ignites the fuel at the end of the compression stroke of the internal combustion engine (15).

15. The fuel injection method according to any one of claims 10 to 14, wherein the fuel injection system (45) is the fuel injection system according to claim 6, wherein the method comprises distributing fuel from the gaseous fuel tank (75) to the high-pressure fuel source (53) and the low-pressure fuel source (57) via the distributor (80), such that: - Each of the gaseous fuel storage tanks (75) containing gaseous fuel at a pressure exceeding the predetermined pressure threshold feeds fuel to the high-pressure fuel source (53) via the distributor (80); and - Each gaseous fuel tank (75) containing gaseous fuel at a pressure below the predetermined pressure threshold feeds fuel to the low-pressure fuel source (57) via the distributor (80).

Images