Fuel supply system of internal combustion engine

Abstract

To suppress wear of a solenoid valve caused by opening and closing operation during fuel pressure control execution.SOLUTION: A fuel supply system 200 for an internal combustion engine 10 includes: a tank 20 for storing fuel; a fuel injection valve 15 for supplying fuel to a cylinder; a fuel passage for supplying fuel in the tank 20 to the fuel injection valve 15; a second shutoff valve 22 provided in the fuel passage to open and close the fuel passage; a temperature raising mechanism 300 for raising the temperature of incoming fuel flowing into the second shutoff valve 22; and a control device 100 for executing fuel pressure control. The fuel pressure control repeatedly drives opening and closing of the second shutoff valve 22 so that the fuel pressure in the fuel passage connected to the downstream side of the second shutoff valve 22 falls within a range specified by predetermined upper and lower limits. During fuel pressure control execution, the control device 100 performs temperature raising by operating the temperature raising mechanism 300 to raise the temperature of the incoming fuel flowing into the second shutoff valve 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fuel supply system for an internal combustion engine. [Background technology]

[0002] For example, the internal combustion engine described in Patent Document 1 reduces the pressure of gaseous fuel stored in a tank and supplies the fuel to a fuel injection valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-182969 Summary of the Invention [Problem to be solved by the invention]

[0004] As the fuel pressure control described above, the following control may be performed. That is, a solenoid valve is provided in a fuel passage connecting a fuel tank and a fuel injection valve that supplies fuel to a cylinder, and allows upper and lower limits to be set for a target fuel pressure. When fuel is injected from the fuel injection valve with the solenoid valve closed, fuel flows out of the fuel passage downstream of the solenoid valve, causing the fuel pressure downstream of the solenoid valve to drop. When this downstream fuel pressure reaches the lower limit, the solenoid valve is opened. This opening of the solenoid valve allows fuel to be supplied to the fuel passage downstream of the solenoid valve, causing the fuel pressure downstream of the solenoid valve to rise. When this downstream fuel pressure reaches the upper limit, the solenoid valve is closed. By repeatedly opening and closing the solenoid valve in this way, the fuel pressure downstream of the solenoid valve, which is the pressure of fuel supplied to the fuel injection valve, is adjusted to be within a predetermined range between the upper and lower limits.

[0005] Here, when fuel pressure control is executed in which the solenoid valve is repeatedly driven to open and close, there is a risk that wear will progress on the sliding parts of the solenoid valve due to the opening and closing operations during execution of fuel pressure control. [Means for solving the problem]

[0006] A fuel supply device for an internal combustion engine that solves the above-mentioned problems includes a tank that stores fuel, a fuel injection valve that supplies fuel to a cylinder, a fuel passage that supplies fuel in the tank to the fuel injection valve, a solenoid valve provided in the fuel passage that opens and closes the fuel passage, a heating mechanism that increases the temperature of the inflow fuel that flows into the solenoid valve, and a processing circuit that executes fuel pressure control. The fuel pressure control is control that repeatedly opens and closes the solenoid valve so that the fuel pressure in the fuel passage connected downstream of the solenoid valve in the direction of fuel flow in the fuel passage is within a pressure range defined by a predetermined upper limit value and a predetermined lower limit value. The processing circuit executes a heating process that operates the heating mechanism to raise the temperature of the inflow fuel while the fuel pressure control is being executed. [Effects of the Invention]

[0007] This fuel supply device for an internal combustion engine can reduce wear on the solenoid valve caused by opening and closing operations during execution of fuel pressure control. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing an internal combustion engine, a fuel supply system, and a control device according to one embodiment. [Figure 2] 2A and 2B are timing charts showing fuel pressure control in this embodiment, where Fig. 2A shows the change in fuel pressure and Fig. 2B shows the operating state of the second shutoff valve. [Figure 3] FIG. 3 is a flowchart showing the procedure of processing executed by the control device of the embodiment. [Figure 4]Figure 4 shows the operation of the temperature increase process in this embodiment, where Figure 4(a) shows the change in the third pressure, Figure 4(b) shows the operating state of the second shutoff valve in this embodiment, and Figure 4(c) shows the operating state of the second shutoff valve in the absence of a temperature increase mechanism. [Figure 5] FIG. 5 is a schematic diagram showing a modified example of the temperature raising mechanism. [Figure 6] FIG. 6 is a schematic diagram showing a modified example of the temperature raising mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a specific embodiment of a fuel supply device for an internal combustion engine will be described with reference to FIGS. <Internal combustion engine, fuel supply device and control device> An internal combustion engine 10 shown in FIG. 1 is mounted on a vehicle and is an internal combustion engine that uses hydrogen gas as a gaseous fuel.

[0010] An intake passage 11 of an internal combustion engine 10 is provided with a throttle valve 12 for adjusting the amount of intake air. The fuel supply device 200 provided in the internal combustion engine 10 includes a fuel injection valve 15, a tank 20, a fuel pipe 40, a first shutoff valve 21, a second shutoff valve 22, a pressure reducing valve 30, a delivery pipe 60, and a temperature raising mechanism 300.

[0011] The fuel injection valve 15 supplies fuel to the cylinder 10 a of the internal combustion engine 10 . The tank 20 stores hydrogen gas, which is a gaseous fuel, in a highly compressed state. The fuel pipe 40 connects the tank 20 and the delivery pipe 60 .

[0012] The fuel injection valve 15 is connected to the delivery pipe 60. The fuel piping 40 and the delivery pipe 60 are a fuel passage connecting the tank 20 and the fuel injection valve 15. The hydrogen gas stored in the tank 20 is supplied to the fuel injection valve 15 via the fuel piping 40 and the delivery pipe 60.

[0013] In the fuel pipe 40, a first shutoff valve 21, a pressure reducing valve 30, and a second shutoff valve 22 are arranged in this order in the direction of fuel flow. The first shutoff valve 21 is an electromagnetic valve and is disposed near the outlet of the tank 20. When the first shutoff valve 21 is open, fuel is supplied from the tank 20 to the fuel pipe 40. When the first shutoff valve 21 is closed, fuel supply from the tank 20 to the fuel pipe 40 is stopped.

[0014] The pressure reducing valve 30 is a valve for reducing the fuel pressure of the hydrogen gas stored in the tank 20 under high pressure to a specified pressure (for example, about 4 MPa) and supplying the fuel to the fuel injection valve 15.

[0015] The second shutoff valve 22 is an electromagnetic valve that is provided in the fuel passage to open and close the fuel passage, and is disposed near the delivery pipe 60. When the second shutoff valve 22 is open due to energization, fuel is supplied to the delivery pipe 60. When the second shutoff valve 22 is closed due to de-energization, fuel supply to the delivery pipe 60 is stopped.

[0016] The first shutoff valve 21 and the second shutoff valve 22 are closed when the internal combustion engine 10 is not operating. On the other hand, the first shutoff valve 21 and the second shutoff valve 22 are basically open when the internal combustion engine 10 is operating.

[0017] A first pressure sensor 81 provided in the fuel pipe 40 between the first shutoff valve 21 and the pressure reducing valve 30 detects a first pressure P1, which is the fuel pressure in the fuel pipe 40 between the first shutoff valve 21 and the pressure reducing valve 30.

[0018] A second pressure sensor 82 provided in the fuel pipe 40 between the pressure reducing valve 30 and the second shutoff valve 22 detects a second pressure P2, which is the fuel pressure in the fuel pipe 40 between the pressure reducing valve 30 and the second shutoff valve 22.

[0019] A third pressure sensor 83 provided in the delivery pipe 60 detects a third pressure P3, which is the fuel pressure in the delivery pipe 60. A temperature sensor 84 provided in the delivery pipe 60 detects a fuel temperature THF, which is the temperature of the fuel in the delivery pipe 60.

[0020] The fuel supply system of the internal combustion engine 10 includes a temperature raising mechanism 300 that raises the temperature of the inflow fuel that flows into the second shutoff valve 22. When the fuel passage connected upstream of the second shutoff valve 22 in the direction of fuel flow in the fuel passage is defined as an upstream fuel passage, the upstream fuel passage in this embodiment includes an upstream fuel pipe 41 that is a fuel pipe that connects the pressure reducing valve 30 and the second shutoff valve 22.

[0021] The temperature raising mechanism 300 has a pipe 330, a first solenoid valve 310 provided at the connection between the pipe 330 and the upstream fuel pipe 41, and a second solenoid valve 320 provided at the connection between the pipe 330 and the upstream fuel pipe 41 at a location downstream of the first solenoid valve 310.

[0022] The pipe 330 is connected in parallel to the upstream fuel pipe 41. A portion of the pipe 330 is arranged to pass near a high-temperature part of the internal combustion engine 10, which is a heat source. Therefore, fuel heated by the heat source flows through the pipe 330. Examples of the high-temperature part of the internal combustion engine 10 include a cylinder block and a cylinder head.

[0023] The first solenoid valve 310 and the second solenoid valve 320 are control valves that control the communication state between the upstream fuel pipe 41 and the pipe 330. The first solenoid valve 310 is provided at the connection between one of the two ends of the pipe 330 and the upstream fuel pipe 41, and the second solenoid valve 320 is provided at the connection between the other of the two ends of the pipe 330 and the upstream fuel pipe 41.

[0024] When the operating positions of the valve elements of the first solenoid valve 310 and the second solenoid valve 320 are set to the first mode, communication between the upstream fuel pipe 41 and the pipe 330 is blocked. Therefore, in this first mode, fuel heated by the heat source does not flow into the upstream fuel pipe 41. On the other hand, when the operating positions of the valve elements of the first solenoid valve 310 and the second solenoid valve 320 are set to the second mode, communication between the upstream fuel pipe 41 and the pipe 330 is established. Therefore, in this second mode, fuel heated by the heat source flows into the upstream fuel pipe 41.

[0025] The control device 100 performs various controls such as fuel injection for the internal combustion engine 10 by controlling various control objects such as the throttle valve 12, the fuel injection valve 15, the first shutoff valve 21, the second shutoff valve 22, the first solenoid valve 310, and the second solenoid valve 320. The control device 100 includes a CPU 110 and a memory 120 configured from a ROM, a RAM, etc., and performs various controls by the CPU 110 executing programs stored in the memory 120.

[0026] The control device 100 refers to various values ​​required for controlling the internal combustion engine 10. For example, the control device 100 refers to the detection values ​​of the first pressure sensor 81, the second pressure sensor 82, the third pressure sensor 83, and the temperature sensor 84. The control device 100 also refers to a detection signal from an accelerator position sensor 71 that detects an accelerator operation amount ACCP, which is an operation amount of an accelerator pedal 27 operated by a driver of a vehicle equipped with the internal combustion engine 10. The control device 100 also refers to a detection signal from a speed sensor 72 that detects a vehicle speed SP of the vehicle equipped with the internal combustion engine 10. The control device 100 also refers to a detection signal from an air flow meter 73 that detects an intake air amount GA of the internal combustion engine 10, and a detection signal Scr from a crank angle sensor 74 that detects a rotation angle of a crankshaft of the internal combustion engine 10.

[0027] The control device 100 calculates the engine speed NE based on the detection signal Scr from the crank angle sensor 74. The control device 100 also calculates the engine load factor KL based on the engine speed NE and the intake air amount GA. The engine load factor KL represents the ratio of the current cylinder inflow air amount to the cylinder inflow air amount when the internal combustion engine 10 is steadily operated at the current engine speed NE under full load. The cylinder inflow air amount is the amount of air that flows into each cylinder during the intake stroke.

[0028] Hydrogen gas, which is the engine fuel, has a wider range of combustible mixtures than gasoline, and can be combusted even in lean mixtures. Therefore, the control device 100 adjusts the output of the internal combustion engine 10 through the following combustion control.

[0029] That is, the control device 100 calculates a required output Pe, which is a required value of the engine output of the internal combustion engine 10, based on the accelerator operation amount ACCP and the like. The control device 100 sets a required injection amount Qd based on the required output Pe. The required injection amount Qd is a target value of fuel injected from one fuel injection valve 15 in one combustion cycle. The control device 100 calculates a required air amount GAd, which is a target value of the intake air amount required to achieve the target air-fuel ratio AFt, based on the target air-fuel ratio AFt and the required injection amount Qd. In this embodiment, the target air-fuel ratio AFt is a lean air-fuel ratio, for example, an excess air ratio λ = 2.5 to 3.0. The control device 100 then controls the fuel injection valve 15 so that an amount of fuel corresponding to the required injection amount Qd is injected. The control device 100 also controls the opening of the throttle valve 12 so that an amount of air corresponding to the required air amount GAd is introduced into the cylinder. In this way, in the internal combustion engine 10, output adjustment is performed by changing the air-fuel ratio of the mixture through adjustment of the fuel injection amount and the intake air amount.

[0030] <Fuel pressure control> The control device 100 executes fuel pressure control to control the pressure of fuel supplied to the fuel injection valve 15, i.e., the fuel pressure in the fuel passage connected downstream of the second shutoff valve 22 in the direction of fuel flow in the fuel passage. This fuel pressure control repeatedly opens and closes the second shutoff valve 22 so that the fuel pressure in the fuel passage connected downstream of the second shutoff valve 22 falls within a control range CR defined by a predetermined upper limit value PtU and a predetermined lower limit value PtL. The target pressure Pt of the fuel pressure in the fuel pressure control is a preset pressure lower than the second pressure P2, which is the fuel pressure after being reduced by the pressure reducing valve 30. For example, the target pressure Pt is approximately 1 MPa. The upper limit value PtU of the fuel pressure that is allowable for the target pressure Pt is set to the lower limit value PtL.

[0031] An example of fuel pressure control is shown in Figure 2. Figure 2(a) shows the change in the third pressure P3, and Figure 2(b) shows the operating state of the second shutoff valve 22. Before time t1, the vehicle is running normally, and the second shutoff valve 22 is maintained in an open state. The third pressure P3 is the same as the second pressure P2, which is the pressure after being reduced by the pressure reducing valve 30.

[0032] At time t1, when an idle operation is requested of the internal combustion engine 10, the second shutoff valve 22 is closed and maintained in that state. While the second shutoff valve 22 is closed, the amount of fuel in the delivery pipe 60 decreases each time fuel is injected from the fuel injection valve 15, and the third pressure P3 gradually decreases.

[0033] At time t2, when the third pressure P3 reaches the lower limit value PtL, the second shutoff valve 22 is opened. This opening of the second shutoff valve 22 causes fuel to be supplied to the fuel passage downstream of the second shutoff valve 22, and the fuel pressure downstream of the second shutoff valve 22 increases. Then, when the third pressure P3 reaches the upper limit value PtU, the second shutoff valve 22 is closed. By repeatedly driving the second shutoff valve 22 to open and close in this manner, the fuel pressure downstream of the second shutoff valve 22, that is, the pressure of the fuel supplied to the fuel injector 15, is adjusted to be within a predetermined control range CR between the upper limit value PtU and the lower limit value PtL.

[0034] In this way, when the required injection amount Qd is small, such as during idling, fuel pressure control is performed to maintain the third pressure P3, which is the fuel pressure in the delivery pipe 60, at a low pressure, so that a small amount of fuel is injected accurately from the fuel injection valve 15.

[0035] At time t3, when the request to execute fuel pressure control is released, second shutoff valve 22 is maintained in an open state. While second shutoff valve 22 is open, fuel is supplied from tank 20 to delivery pipe 60, so that third pressure P3 gradually increases toward second pressure P2.

[0036] <Temperature increase treatment> When the above-described fuel pressure control is performed in which the second shutoff valve 22 is repeatedly driven to open and close, the opening and closing operations during the fuel pressure control may cause wear on the sliding parts of the second shutoff valve 22. Furthermore, the opening and closing operations during the fuel pressure control may cause the electromagnetic coil of the second shutoff valve 22 to generate heat. To prevent such problems from occurring, the control device 100 performs a temperature increase process during the fuel pressure control, which operates the temperature increase mechanism 300 so that the temperature of the fuel flowing into the second shutoff valve 22 is increased. Note that, hereinafter, the fuel flowing into the second shutoff valve 22 is referred to as the inflow fuel.

[0037] Figure 3 shows the procedure for the temperature increase process executed by the control device 100. The process shown in Figure 3 is implemented by the CPU 110 executing a program stored in the memory 120 of the control device 100. The process shown in Figure 3 is started when there is a request to execute fuel pressure control. Incidentally, a request to execute fuel pressure control is made, for example, when the operating state of the internal combustion engine 10 transitions to an idle operating state. In the following, step numbers are represented by numbers preceded by "S."

[0038] When this process starts, the control device 100 determines whether the third pressure P3 is equal to or less than the lower limit value PtL (S100). Then, the control device 100 repeatedly executes the process of S100 until it is determined that the third pressure P3 is equal to or less than the lower limit value PtL.

[0039] If it is determined in the processing of S100 that the third pressure P3 is equal to or less than the lower limit value PtL (S100: YES), the control device 100 operates the first solenoid valve 310 and the second solenoid valve 320 to set them to the second mode (S110). When the first solenoid valve 310 and the second solenoid valve 320 are set to the second mode, the upstream fuel pipe 41 and the pipe 330 are brought into communication with each other. Therefore, fuel that has received heat from the internal combustion engine 10, which is a heat source, flows into the upstream fuel pipe 41, and the temperature of the fuel flowing into the second shutoff valve 22 is increased.

[0040] Next, the control device 100 determines whether or not there is currently a request to execute fuel pressure control (S120), and the control device 100 repeatedly executes the process of S120 until it is determined that there is no request to execute fuel pressure control.

[0041] If it is determined in the processing of S120 that there is no request to execute fuel pressure control, the control device 100 operates the first solenoid valve 310 and the second solenoid valve 320 to set them to the first mode (S130). When the first solenoid valve 310 and the second solenoid valve 320 are set to the first mode, the upstream fuel pipe 41 and the pipe 330 are not in communication with each other. Therefore, the temperature of the fuel flowing into the second shutoff valve 22 is no longer increased. Note that the control device 100 determines that there is no request to execute fuel pressure control when, for example, the operating state of the internal combustion engine 10 shifts to a state where the engine load is higher than the idle operating state.

[0042] After executing the process of S130, the control device 100 ends this process. <Operation of this embodiment> FIG. 4 shows the operation of the temperature increase process. FIG. 4(a) shows the change in third pressure P3 during fuel pressure control. The solid line in FIG. 4(a) shows the change in third pressure P3 in this embodiment, and the two-dot chain line in FIG. 4(a) shows the change in third pressure P3 in a comparative example to this embodiment, in which the temperature increase mechanism 300 is not provided. FIG. 4(b) shows the operating state of second shutoff valve 22 in this embodiment. And FIG. 4(c) shows the operating state of second shutoff valve 22 in a comparative example to this embodiment, in which the temperature increase mechanism 300 is not provided.

[0043] During fuel pressure control, the upstream fuel pipe 41 and the pipe 330 are in communication, and fuel heated by the internal combustion engine 10, which is a heat source, flows into the second shutoff valve 22. Therefore, in this embodiment, during fuel pressure control, the temperature of the inflow fuel flowing into the second shutoff valve 22 increases. When the temperature of the inflow fuel increases in this manner, the viscosity of the inflow fuel increases and the density decreases. Therefore, the mass flow rate of the fuel flowing into the fuel passage connected downstream of the second shutoff valve 22 decreases, and the rate of increase of the third pressure P3, which is the fuel pressure in the fuel passage, becomes slower than in the comparative example. When the rate of increase of the third pressure P3 becomes slower, the time it takes for the third pressure P3 to reach the upper limit value PtU becomes longer, and therefore the valve opening time Top of the second shutoff valve 22 becomes longer than the valve opening time Topc in the comparative example. When the open time Top of the second shutoff valve 22 is increased, the opening / closing cycle CY of the second shutoff valve 22 becomes longer than the opening / closing cycle CYc in the comparative example, and therefore the number of times the second shutoff valve 22 is opened and closed during execution of fuel pressure control decreases.

[0044] <Effects of this embodiment> (1) During fuel pressure control, the control device 100 executes a temperature increase process that operates the temperature increase mechanism 300 so as to increase the temperature of the inflow fuel that flows into the second shutoff valve 22. This increases the temperature of the inflow fuel that flows into the second shutoff valve 22. When the temperature of the inflow fuel that flows into the second shutoff valve 22 increases, as described above, the number of times the second shutoff valve 22 is opened and closed during fuel pressure control decreases. Therefore, wear on the second shutoff valve 22 that occurs due to the opening and closing operation can be reduced. Furthermore, because the number of times the second shutoff valve 22 is opened and closed is reduced, heat generation by the second shutoff valve 22 can also be reduced.

[0045] (2) Since the opening / closing cycle CY of the second shutoff valve 22 is lengthened, the fluctuation cycle of the third pressure P3 is also lengthened. As a result, fluctuations in the fuel pressure of the fuel supplied to the fuel injector 15 can be suppressed. (3) The temperature raising mechanism 300 includes a pipe 330 through which fuel heated by the internal combustion engine 10, which is a heat source, flows and which is connected in parallel to the upstream fuel pipe 41, and a first solenoid valve 310 and a second solenoid valve 320 that control the communication state between the upstream fuel pipe 41 and the pipe 330. The control device 100 then executes a temperature raising process to operate both the first solenoid valve 310 and the second solenoid valve 320 so that the upstream fuel pipe 41 and the pipe 330 are in communication with each other. Therefore, during fuel pressure control, the fuel heated by the internal combustion engine 10 flows from the pipe 330 to the upstream fuel pipe 41. Therefore, during fuel pressure control, the temperature of the inflow fuel flowing into the second shutoff valve 22 can be raised.

[0046] (4) The fuel used in the internal combustion engine 10 is gaseous fuel. Unlike liquid fuels such as gasoline, gaseous fuel has poor lubricity. Therefore, the second shutoff valve 22, which is repeatedly opened and closed, is prone to wear due to sliding. In this regard, according to this embodiment, as described above, the number of times the second shutoff valve 22 is opened and closed while fuel pressure control is being executed is reduced. Therefore, wear on the second shutoff valve 22 provided in the fuel system of the internal combustion engine 10 that uses gaseous fuel can be suppressed.

[0047] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0048] As shown in Fig. 5, the internal combustion engine 10 is equipped with a radiator 90 that exchanges heat with the coolant of the internal combustion engine 10. A portion of the pipe 330 may be arranged to pass near the radiator 90, which is a heat source. In this case, the radiator 90 becomes the heat source of the temperature raising mechanism 300. In this modified example, the pipe 330 is preferably arranged on the side of the radiator 90 from which the running wind flows out. Alternatively, a portion of the pipe 330 may be configured to pass through the inside of the radiator 90.

[0049] As shown in FIG. 6 , the temperature-raising mechanism 300 may include a heater 350 provided in the upstream fuel pipe 41. The control device 100 may then execute, as the temperature-raising process, a process of controlling the operating state of the heater 350 so as to raise the temperature of the fuel flowing through the upstream fuel pipe 41. For example, if the heater 350 is electric, the control device 100 may execute, as the temperature-raising process, a process of changing the operating state of the heater 350 from off to on by operating a power supply circuit 360 that controls the supply of electricity to the heater 350. Furthermore, for example, if the heater 350 uses the coolant of the internal combustion engine 10 as a heat source, the control device 100 can execute the following process as the temperature-raising process. That is, the control device 100 may execute, as the temperature-raising process, a process of changing the operating state of the heater 350 from a low temperature state to a high temperature state by operating a valve that controls on / off of the circulation of coolant to the heater 350.

[0050] A temperature sensor is provided in the upstream fuel pipe 41 to detect the fuel temperature TH, which is the temperature of the fuel flowing into the second shutoff valve 22. If the fuel temperature TH reaches a predetermined upper limit temperature THU while fuel pressure control is being executed, the temperature increase process is stopped. On the other hand, if the fuel temperature TH reaches a predetermined lower limit temperature THL, which is lower than the upper limit temperature THU while fuel pressure control is being executed, the temperature increase process may be executed.

[0051] Either the first solenoid valve 310 or the second solenoid valve 320 may be omitted. The second shutoff valve 22 may be a two-stage valve having a small flow rate pilot valve suitable for adjusting the fuel injection amount when the required injection amount Qd is small, and a large flow rate main valve suitable for adjusting the fuel injection amount when the required injection amount Qd is large. In this case, it is preferable to perform the temperature increase process described above when fuel pressure control is performed by the pilot valve.

[0052] A temperature raising mechanism 300 may be provided in the fuel pipe 40 between the first shutoff valve 21 and the pressure reducing valve 30 . The fuel for the internal combustion engine 10 is hydrogen gas, which is a gaseous fuel, but other gaseous fuels, such as compressed natural gas, may also be used.

[0053] The fuel used in the internal combustion engine 10 is gaseous fuel, but it may be liquid fuel. The control device 100 is not limited to a device equipped with a CPU and memory and executing software processing. For example, the control device 100 may be equipped with a dedicated hardware circuit, such as an ASIC, that performs hardware processing on at least a portion of the software processing performed in the above embodiments. That is, the control device 100 may include a processing circuit having any of the following configurations (a) to (c): (a) a processing circuit equipped with one or more processing devices that execute all of the above processing according to a program and one or more program storage devices, such as ROM, that store the program; (b) a processing circuit equipped with one or more processing devices and one or more program storage devices that execute part of the above processing according to a program, and one or more dedicated hardware circuits that execute the remaining processing; (c) a processing circuit equipped with one or more dedicated hardware circuits that execute all of the above processing. Program storage devices, i.e., computer-readable media, include any available media that can be accessed by a general-purpose or dedicated computer. [Explanation of symbols]

[0054] 10...Internal combustion engine 10a...cylinder 11...Intake passage 12...Throttle valve 12...Throttle valve passage 15...Fuel injection valve 20...Tank 21...First shutoff valve 22...Second shutoff valve 27...Accelerator pedal 30...Reducing valve 40…Fuel piping 60...Delivery pipe 71...Accelerator position sensor 72...Speed ​​sensor 73...Air flow meter 74...Crank angle sensor 81...First pressure sensor 82...Second pressure sensor 83...Third pressure sensor 100...Control device 110...CPU 120...Memory 200…Fuel supply device 300...heating mechanism

Claims

1. A fuel supply device for an internal combustion engine, comprising: The fuel supply device is a fuel injection valve that supplies fuel to a cylinder; a fuel passage that supplies fuel from the tank to the fuel injection valve; a solenoid valve that is provided in the fuel passage and opens and closes the fuel passage; a temperature raising mechanism that raises the temperature of inflow fuel that flows into the solenoid valve; and a processing circuit that executes fuel pressure control, the fuel pressure control is a control that repeatedly drives the solenoid valve to open and close so that the fuel pressure in the fuel passage connected downstream of the solenoid valve in the direction of fuel flow in the fuel passage is within a pressure range defined by a predetermined upper limit value and a predetermined lower limit value, The processing circuit executes a temperature increase process for operating the temperature increase mechanism so as to increase the temperature of the inflow fuel during the execution of the fuel pressure control. Fuel supply system for internal combustion engines.

2. When the fuel passage connected upstream of the solenoid valve in the fuel flow direction in the fuel passage is defined as an upstream fuel passage, the temperature raising mechanism includes a pipe through which fuel heated by a heat source flows and which is connected in parallel to the upstream fuel passage, and an operation valve that operates a communication state between the upstream fuel passage and the pipe, The temperature increase process is a process of operating the operating valve so that the upstream fuel passage and the pipe are in a communication state.

2. A fuel supply system for an internal combustion engine according to claim 1.

3. The heat source is the internal combustion engine.

3. A fuel supply system for an internal combustion engine according to claim 2.

4. The heat source is a radiator that exchanges heat with the cooling water of the internal combustion engine.

3. A fuel supply system for an internal combustion engine according to claim 2.

5. When the fuel passage connected upstream of the solenoid valve in the fuel flow direction in the fuel passage is defined as an upstream fuel passage, the temperature raising mechanism is a heater provided in the upstream fuel passage, The temperature increase process is a process of manipulating the operating state of the heater so as to increase the temperature of the fuel flowing through the upstream fuel passage.

2. A fuel supply system for an internal combustion engine according to claim 1.

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