Fuel supply device for internal combustion engine

Abstract

To suppress wear of a solenoid valve caused by an opening / closing operation during execution of fuel pressure control.SOLUTION: A fuel supply device 200 for an internal combustion engine 10 includes: a tank 20 that stores 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 shut-off valve 22 provided in the fuel passage to open / close the fuel passage; a volume variable mechanism 300 that when the fuel passage connected to a downstream side of the second shut-off valve 22 in a fuel flowing direction in the fuel passage is defined as a downstream side fuel passage, varies a volume of the downstream side fuel passage; and a control device 100 that executes fuel pressure control. The fuel pressure control is control for repeatedly performing opening / closing operation of the second shut-off valve 22 so that fuel pressure in the downstream side fuel passage becomes pressure within a range specified by a prescribed upper limit value and a prescribed lower limit value. The control device 100 executes volume increase processing for operating the volume variable mechanism 300 so as to increase the volume of the downstream side fuel passage during execution of the fuel pressure control.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 and opening and closing the fuel passage, a volume variable mechanism that varies the volume of a downstream fuel passage when the fuel passage connected downstream of the solenoid valve in the direction of fuel flow in the fuel passage is defined as the downstream fuel passage, 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 downstream fuel passage is within a pressure range defined by a predetermined upper limit value and a predetermined lower limit value. During execution of the fuel pressure control, the processing circuit executes a volume increase process that operates the volume variable mechanism to increase the volume of the downstream fuel passage. [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 volume increasing 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 volume varying mechanism. [Figure 5] FIG. 5 is a schematic diagram showing a modified example of the volume variable mechanism. [Figure 6] FIG. 6 is a schematic diagram showing a modified example of the volume variable 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 volume varying 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] When a fuel passage connected downstream of second shutoff valve 22 in the direction of fuel flow in the fuel passage is defined as a downstream fuel passage, the fuel supply system of internal combustion engine 10 includes volume variable mechanism 300 that varies the volume of the downstream fuel passage. The downstream fuel passage in this embodiment includes downstream fuel pipe 41, which is a fuel pipe that connects second shutoff valve 22 and delivery pipe 60, and delivery pipe 60.

[0021] The volume varying mechanism 300 has a pipe 330 , a first solenoid valve 310 provided in the pipe 330 , and a second solenoid valve 320 provided in the pipe 330 . Both ends of the pipe 330 are connected to the downstream fuel pipe 41. Therefore, the pipe 330 is connected in parallel to the downstream fuel pipe 41. The volume V of the internal space of the pipe 330, which is determined by the inner diameter and pipe length of the pipe 330, is set to an appropriate value taking into consideration the valve closing time Tcl, which will be described later.

[0022] The first solenoid valve 310 and the second solenoid valve 320 are control valves that control the communication state between the downstream fuel pipe 41 and the pipe 330. The first solenoid valve 310 is provided near one of the ends of the pipe 330, and the second solenoid valve 320 is provided near the other of the ends of the pipe 330.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] Hydrogen gas, which is the engine fuel, has a wider range of combustible mixtures than gasoline, and can combust even lean mixtures. Therefore, the control device 100 adjusts the output of the internal combustion engine 10 through the following combustion control.

[0027] 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.

[0028] <Fuel pressure control> The control device 100 executes fuel pressure control. The fuel pressure control repeatedly opens and closes the second shutoff valve 22 so that the fuel pressure in the downstream fuel passage, which is equal to the pressure of the fuel supplied to the fuel injection valve 15, falls within a control range CR defined by a predetermined upper limit value PtU and a predetermined lower limit value PtL. The target fuel pressure Pt 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 about 1 MPa. The upper limit value PtU of the fuel pressure that is allowable for the target pressure Pt is set. The lower limit value PtL of the fuel pressure that is allowable for the target pressure Pt is set.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] <Volume increase treatment> When the above-described fuel pressure control is executed in which the second shutoff valve 22 is repeatedly driven to open and close, the opening and closing operations during the execution of the fuel pressure control may cause wear on the sliding parts of the second shutoff valve 22. Also, the opening and closing operations during the execution of the fuel pressure control may cause heat to be generated in the electromagnetic coil of the second shutoff valve 22. Therefore, the control device 100 executes a volume increase process during the execution of the fuel pressure control in which the volume variable mechanism 300 is operated to increase the volume of the downstream fuel passage.

[0035] Figure 3 shows the procedure for the volume 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."

[0036] 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.

[0037] If it is determined in the process of S100 that the third pressure P3 is equal to or less than the lower limit value PtL (S100: YES), the control device 100 opens both the first solenoid valve 310 and the second solenoid valve 320 (S110). When both the first solenoid valve 310 and the second solenoid valve 320 are opened, the downstream fuel pipe 41 and the pipe 330 are brought into communication with each other. This increases the volume of the downstream fuel passage.

[0038] 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.

[0039] If it is determined in the processing of S120 that there is no request to execute fuel pressure control, the control device 100 closes both the first solenoid valve 310 and the second solenoid valve 320 (S130). When both the first solenoid valve 310 and the second solenoid valve 320 are closed, the downstream fuel pipe 41 and the pipe 330 are not in communication with each other. Therefore, the volume of the downstream fuel passage returns to the volume before the increase. 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 transitions to a state where the engine load is higher than the idle operating state.

[0040] After executing the process of S130, the control device 100 ends this process. <Operation of this embodiment> FIG. 4 shows the effect of the volume 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 volume variable mechanism 300 is not included. FIG. 4(b) shows the operating state of the second shutoff valve 22 in this embodiment. And FIG. 4(c) shows the operating state of the second shutoff valve 22 in a comparative example to this embodiment, in which the volume variable mechanism 300 is not included.

[0041] During fuel pressure control, the downstream fuel pipe 41 and the pipe 330 communicate with each other, increasing the volume of the downstream fuel passage. Therefore, in this embodiment, the rate at which the third pressure P3 decreases during fuel pressure control is slower than in the comparative example. When the rate at which the third pressure P3 decreases is slower, the time it takes for the third pressure P3 to reach the lower limit value PtL increases, and therefore the closing time Tcl of the second shutoff valve 22 becomes longer than the closing time Tclc in the comparative example. When the closing time Tcl of the second shutoff valve 22 is longer, 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 opens and closes during fuel pressure control decreases.

[0042] <Effects of this embodiment> (1) During fuel pressure control, the control device 100 executes a volume increase process that operates the volume variable mechanism 300 to increase the volume of the downstream fuel passage. This increases the volume of the downstream fuel passage during fuel pressure control. When the volume of the downstream fuel passage is increased, as described above, the number of times the second shutoff valve 22 is opened and closed during fuel pressure control is reduced. This reduces wear on the second shutoff valve 22 that occurs during the opening and closing operation. Furthermore, because the number of times the second shutoff valve 22 is opened and closed is reduced, heat generation in the second shutoff valve 22 is also reduced.

[0043] (2) The volume variable mechanism 300 includes a pipe 330 connected at both ends to the downstream fuel pipe 41, and a first solenoid valve 310 and a second solenoid valve 320 that control the communication state between the downstream fuel pipe 41 and the pipe 330. As a volume increasing process, the control device 100 executes a process of opening both the first solenoid valve 310 and the second solenoid valve 320 so that the downstream fuel pipe 41 and the pipe 330 are in a communication state. Therefore, while fuel pressure control is being executed, the volume of the downstream fuel passage increases by the volume V of the internal space of the pipe 330. Therefore, the volume of the downstream fuel passage can be increased while fuel pressure control is being executed.

[0044] (3) 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.

[0045] <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.

[0046] As shown in FIG. 5 , the volume variable mechanism 300 may include a pipe 340 having a first end 340A closed and a second end 340B connected to the downstream fuel pipe 41, and a solenoid valve 350 that controls the communication state between the downstream fuel pipe 41 and the pipe 340. The solenoid valve 350 is preferably provided near the second end 340B of the pipe 340. The control device 100 may then execute a volume increasing process to open the solenoid valve 350 so that the downstream fuel pipe 41 and the pipe 340 are in communication with each other. Even in this case, the volume of the downstream fuel passage increases by the volume of the internal space of the pipe 340 during fuel pressure control. Therefore, even in this modification, the volume of the downstream fuel passage can be increased during fuel pressure control.

[0047] As shown in FIG. 6 , the volume varying mechanism 300 may include a pressure accumulator 370 connected to the downstream fuel pipe 41 and a solenoid valve 360 ​​that is an operating valve that controls the communication state between the downstream fuel pipe 41 and the pressure accumulator 370. The downstream fuel pipe 41 and the pressure accumulator 370 may be connected via a pipe 380. The solenoid valve 360 ​​may be provided on the pipe 380. Although not shown, the pressure accumulator 370 may be directly connected to the downstream fuel pipe 41, or the solenoid valve 360 ​​may be provided at the connection between the pressure accumulator 370 and the downstream fuel pipe 41. The control device 100 may then execute a volume increasing process to open the solenoid valve 360 ​​so that the downstream fuel pipe 41 and the pressure accumulator 370 are in a communication state. Even in this case, the volume of the downstream fuel passage increases by at least the volume of the internal space of the pressure accumulator 370 during fuel pressure control. Therefore, in this modification as well, the volume of the downstream fuel passage can be increased while fuel pressure control is being executed.

[0048] The volume variable mechanism 300 may be provided in the delivery pipe 60. 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.

[0049] 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]

[0050] 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...Variable volume 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 in 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 volume varying mechanism that varies the volume of a downstream fuel passage when the fuel passage connected downstream of the solenoid valve in the direction of fuel flow in the fuel passage is defined as the downstream fuel passage; and a processing circuit that executes fuel pressure control, the fuel pressure control is a control that repeatedly opens and closes the solenoid valve so that the fuel pressure in the downstream 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 volume increasing process for operating the volume varying mechanism so as to increase the volume of the downstream fuel passage during the execution of the fuel pressure control. Fuel supply system for internal combustion engines.

2. the volume varying mechanism includes a pipe connected at both ends to the downstream fuel passage, and an operating valve that operates a communication state between the downstream fuel passage and the pipe, The volume increasing process is a process of opening the operating valve so that the downstream 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 volume varying mechanism includes a pipe having a first end closed and a second end connected to the downstream fuel passage, and an operating valve that operates a communication state between the downstream fuel passage and the pipe, The volume increasing process is a process of opening the operating valve so that the downstream fuel passage and the pipe are in a communication state.

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

4. the volume varying mechanism includes a pressure accumulator connected to the downstream fuel passage, and an operating valve that operates a communication state between the downstream fuel passage and the pressure accumulator, The volume increasing process is a process of opening the operating valve so that the downstream fuel passage and the pressure accumulator are in a communication state.

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

5. The fuel for the internal combustion engine is a gaseous fuel.

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

Images