Fuel supply system for internal combustion engines

Abstract

The time from when power is supplied until the second valve body of the solenoid valve opens is shortened. [Solution] The fuel supply device 300 includes a fuel pipe 40 for an internal combustion engine and a second shut-off valve 22, which is a solenoid valve, provided in the fuel pipe 40. The second shut-off valve 22 has a first valve body that, when opened by energization, allows fuel to flow from the upstream side to the downstream side of the second shut-off valve 22, and a second valve body that opens when the pressure on the downstream side of the second shut-off valve 22 exceeds a predetermined opening pressure due to the fuel inflow to the downstream side of the second shut-off valve 22 caused by the opening of the first valve body. The downstream pipe 41 connected to the downstream side of the second shut-off valve 22 includes a downstream valve 90 that opens after the timing when the second valve body opens.

Description

Technical Field

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

Background Art

[0002] For example, the fuel supply device for an internal combustion engine described in Patent Document 1 has a shut-off valve, which is a solenoid valve, in a fuel passage connecting a fuel tank and a fuel injection valve. At the start of the internal combustion engine, by appropriately controlling the valve opening timing of the shut-off valve, gaseous fuel at a required pressure is supplied to the fuel injection valve to improve the starting performance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As the structure of the solenoid valve, it is conceivable to include a first valve body and a second valve body. The first valve body allows the inflow of fuel from the upstream side to the downstream side of the solenoid valve by opening when energized. The second valve body opens when the pressure on the downstream side of the solenoid valve becomes equal to or higher than a predetermined value due to the inflow of fuel to the downstream side of the solenoid valve caused by the opening of the first valve body. According to the solenoid valve provided with the second valve body that opens and closes according to such pressure, the magnetic force required for opening the second valve body can be reduced. When the magnetic force required for opening is reduced, for example, the solenoid valve can be miniaturized or the power consumption can be reduced.

[0005] Here, during the closing of the second valve body, the downstream pressure of the solenoid valve is a low pressure lower than the predetermined value. Therefore, in order to open the second valve body, it is necessary to increase the decreasing downstream pressure to the predetermined value, which takes time for the pressure boost. Therefore, there is a possibility that the time from the start of energization until the second valve body opens becomes long. [Means for solving the problem]

[0006] A fuel supply device for an internal combustion engine that solves the above problems comprises a fuel passage for the internal combustion engine and a solenoid valve provided in the fuel passage. The solenoid valve has a first valve body that, when opened by energization, allows fuel to flow from the upstream side to the downstream side of the solenoid valve, and a second valve body that opens when the pressure on the downstream side of the solenoid valve exceeds a predetermined opening pressure due to the fuel inflow to the downstream side of the solenoid valve caused by the opening of the first valve body. The fuel passage connected to the downstream side of the solenoid valve is provided with a valve that opens after the timing at which the second valve body opens. [Effects of the Invention]

[0007] This fuel supply system for internal combustion engines can shorten the time from when power is supplied until the second valve body of the solenoid valve opens. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an internal combustion engine, fuel supply system, and control device in one embodiment. [Figure 2] Figure 2 is a cross-sectional view showing the structure of the second shut-off valve in the same embodiment. [Figure 3] Figure 3 is a timing chart showing the operation of the embodiment. (a) shows the change in downstream pressure, (b) shows the change in the open / closed state of the first valve, (c) shows the change in the open / closed state of the second valve, and (d) shows the change in the open / closed state of the downstream valve. [Figure 4] Figure 4 is a schematic diagram showing an internal combustion engine, fuel supply system, and control device in a modified example of the same embodiment. [Figure 5] Figure 5 is a timing chart showing the opening and closing control of the downstream valve in the modified example. (a) shows the change in downstream pressure, (b) shows the change in the open / closed state of the first valve, (c) shows the change in the open / closed state of the second valve, and (d) shows the change in the open / closed state of the downstream valve. [Modes for carrying out the invention]

[0009] Below, one embodiment of a fuel supply system for an internal combustion engine will be described with reference to Figures 1 to 3. <Internal combustion engines, fuel supply systems, and control devices> The internal combustion engine 10 shown in Figure 1 is mounted on a vehicle and is an internal combustion engine that uses hydrogen gas, a fluid gaseous fuel, as fuel.

[0010] The intake passage 11 of the internal combustion engine 10 is provided with a throttle valve 12 for adjusting the amount of intake air. The fuel supply system 300 provided by the internal combustion engine 10 includes a fuel injection valve 15, a tank 20, fuel piping 40, a first shut-off valve 21, a second shut-off valve 22, a pressure reducing valve 30, a delivery pipe 60, and a downstream valve 90.

[0011] The fuel injector 15 supplies fuel to the cylinder 10a of the internal combustion engine 10. The tank 20 stores hydrogen gas, a gaseous fuel, in a compressed state. The fuel piping 40 connects the tank 20 to the delivery pipe 60. The fuel injector 15 is connected to the delivery pipe 60. The fuel piping 40 and the delivery pipe 60 are fuel passages connecting the tank 20 and the fuel injector 15. The hydrogen gas stored in the tank 20 is supplied to the fuel injector 15 via the fuel piping 40 and the delivery pipe 60.

[0012] The fuel piping 40 is equipped with, in order from the direction of fuel flow, a first shut-off valve 21, a pressure reducing valve 30, a second shut-off valve 22, and a downstream valve 90. In the following, the upstream side in the direction of fuel flow will be referred to as "upstream," and the downstream side in the direction of fuel flow will be referred to as "downstream."

[0013] The first shut-off valve 21 is a solenoid valve and is located near the outlet of the tank 20. When the first shut-off valve 21 is open, fuel is supplied from the tank 20 to the fuel piping 40. When the first shut-off valve 21 is closed, the fuel supply from the tank 20 to the fuel piping 40 is stopped.

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

[0015] The second shut-off valve 22 is an electromagnetic valve and is disposed in the fuel pipe 40 in the vicinity of the delivery pipe 60. When the second shut-off valve 22 is open due to energization, fuel is supplied to the delivery pipe 60. When the second shut-off valve 22 is closed due to power-off, the fuel supply to the delivery pipe 60 is stopped.

[0016] The first shut-off valve 21 and the second shut-off valve 22 are closed during the stop of the operation of the internal combustion engine 10. On the other hand, the first shut-off valve 21 and the second shut-off valve 22 are basically open during the operation of the internal combustion engine 10.

[0017] The first pressure sensor 81 provided in the fuel pipe 40 between the first shut-off valve 21 and the pressure reducing valve 30 detects the first pressure P1, which is the fuel pressure in the fuel pipe 40 between the first shut-off valve 21 and the pressure reducing valve 30. The second pressure sensor 82 provided in the fuel pipe 40 between the pressure reducing valve 30 and the second shut-off valve 22 detects the second pressure P2, which is the fuel pressure in the fuel pipe 40 between the pressure reducing valve 30 and the second shut-off valve 22. The third pressure sensor 83 provided in the delivery pipe 60 detects the third pressure P3, which is the fuel pressure of the delivery pipe 60. The temperature sensor 84 provided in the delivery pipe 60 detects the fuel temperature THF, which is the temperature of the fuel in the delivery pipe 60.

[0018] The second shut-off valve 22 and the delivery pipe 60 are connected by a downstream pipe 41. The downstream pipe 41 is a part of the fuel pipe 40 and constitutes a part of the fuel passage connected to the downstream side of the second shut-off valve 22.

[0019] The downstream valve 90 is provided in the downstream piping 41. The downstream valve 90 is a valve that opens after the timing when the second valve 220 described later opens. This downstream valve 90 is composed of a check valve that opens when the pressure in the fuel passage between the downstream valve 90 and the second shut-off valve 22 becomes equal to or higher than the second opening pressure Pb, allowing fuel to flow from the upstream side to the downstream side of the downstream valve 90. The second opening pressure Pb is set to a value within a range that is equal to or higher than the first opening pressure Pa described later and lower than the pressure on the upstream side of the second shut-off valve 22. The pressure on the upstream side of the second shut-off valve 22 is the pressure of the fuel flowing into the second shut-off valve 22, and is equal to the second pressure P2 which is the pressure of the fuel after being depressurized by the pressure reducing valve 30.

[0020] The control device 100 performs various controls such as fuel injection of the internal combustion engine 10 by controlling various control targets such as the throttle valve 12, the fuel injection valve 15, the first shut-off valve 21, and the second shut-off valve 22. This control device 100 includes a CPU 110 and a memory 120 composed of a ROM and a RAM, etc. The CPU 110 executes a program stored in the memory 120 to perform various controls.

[0021] The control device 100 refers to various values necessary for the control of 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. In addition, the control device 100 refers to the detection signal of the accelerator position sensor 71 that detects the accelerator operation amount ACCP which is the operation amount of the accelerator pedal 27 operated by the driver of the vehicle equipped with the internal combustion engine 10. In addition, the control device 100 refers to the detection signal of the speed sensor 72 that detects the vehicle speed SP of the vehicle equipped with the internal combustion engine 10. In addition, the control device 100 refers to the detection signal of the air flow meter 73 that detects the intake air amount GA of the internal combustion engine 10 and the detection signal Scr of the crank angle sensor 74 that detects the rotation angle of the crankshaft of the internal combustion engine 10.

[0022] <Structure of the second shut-off valve> Figure 2 shows the structure of the second shut-off valve 22. In the following, the direction along the central axis L of the plunger 211 of the second shut-off valve 22 is referred to as the axial direction. The direction perpendicular to the axial direction is referred to as the radial direction.

[0023] The second shut-off valve 22 includes a housing 200, a stator 230, an electromagnetic coil 240, a first valve 210, a holder 250, a second valve 220, and the like. The housing 200 includes an inlet port 201 to which a fuel pipe 40 connected to a pressure reducing valve 30 is connected, and an outlet port 203 to which a fuel pipe 40 connected to a delivery pipe 60 is connected.

[0024] The inlet port 201 and the outlet port 203 are in communication via the first chamber 202, which is a space formed within the housing 200. The stator 230 is cylindrical and is located inside the housing 200.

[0025] The electromagnetic coil 240 is located on the outer circumference of the stator 230. The electromagnetic coil 240 opens the valve body when energized. The first valve body, the first valve 210, includes a plunger 211 that moves axially within the stator 230, and a first sealing member 213 that opens and closes the first fuel passage 222 as the plunger 211 moves.

[0026] One end of the plunger 211 is a protruding portion 212 that extends from the stator 230. The tip of the protruding portion 212 is provided with the first sealing member 213. The protruding portion 212 is also equipped with a radially extending pin 214. Both ends of the pin 214 protrude from the outer circumferential surface of the protruding portion 212.

[0027] The holder 250 has a cylindrical portion 251 that is coaxial with the central axis L. The inner circumferential surface of the cylindrical portion 251 is spaced apart from the outer circumferential surface of the protrusion 212. The second valve body, the second valve 220, is slidably housed on the inner circumferential surface of the cylindrical portion 251. The second valve 220 has a hole 221 through which the outer circumferential surface of the projection 212 of the first valve 210 slides. The second valve 220 has an elongated hole 225 into which the pin 214 is inserted and which allows the pin 214 to move in the axial direction.

[0028] The tip of the second valve 220 has a first fuel passage 222 that extends in the axial direction. The first fuel passage 222 is connected to the outlet port 203 which constitutes the second fuel passage. The outlet port 203 is a fuel passage with a larger flow path cross-sectional area than the first fuel passage 222.

[0029] The tip of the second valve 220 is provided with a second sealing member 224 that opens and closes the outlet port 203. More specifically, the second sealing member 224 opens and closes a second valve seat 204 provided at one end of the outlet port 203.

[0030] A first valve seat 223 is formed at the tip of the second valve 220, in which the first fuel passage 222 is formed, and protrudes toward the protruding portion 212. The first fuel passage 222 is opened and closed by the opening and closing of the first valve seat 223 by the first sealing member 213. This first fuel passage 222 is a communication passage that connects the flow path upstream of the second valve 220, which is the second valve body, with the flow path downstream of the second valve 220. The flow path upstream of the second valve 220 is the pressure chamber 227, the communication passage 226, the first chamber 202, and the inlet port 201, which will be described later. The flow path downstream of the second valve 220 is the outlet port 203. The first valve 210 is a first valve body that opens prior to the opening of the second valve 220 and opens and closes the first fuel passage 222.

[0031] In the hole 221, the space enclosed by the wall surface around the first valve seat 223 and the tip surface of the projection 212 forms a pressure chamber 227 through which pressure acts to bias the second valve 220 in the closing direction. This pressure chamber 227 is connected to the first chamber 202 via a connecting passage 226.

[0032] A second chamber 255 is formed on the inner circumferential surface side of the cylindrical portion 251 of the holder 250, which is a space for securing the axial stroke amount of the second valve 220. The end face 228 of the second valve 220, which is opposite to the side on which the second sealing member 224 is disposed, and the restricting portion 253 of the holder 250, which is the surface facing the end face 228, come into contact with each other when the second valve 220 is fully open. By maintaining this contact between the end face 228 and the restricting portion 253, the position of the valve body is stabilized when the second valve 220 is fully open.

[0033] An end cap 280 is provided inside the stator 230, at the end opposite to the side into which the plunger 211 is inserted, to close that end. A third chamber 257, which is a space, is formed between the end cap 280 and the plunger 211. A spring 215 is also provided between the end cap 280 and the plunger 211 to bias the plunger 211 in a direction away from the end cap 280.

[0034] <Opening operation of the second shut-off valve> When the engine starts, energizing the electromagnetic coil 240 is initiated, causing the plunger 211 to be retracted into the stator 230. This causes the first valve 210 to move in a direction that separates the first sealing member 213 from the first valve seat 223. This movement of the first valve 210 causes the first valve 210 to open. Once the first sealing member 213 separates from the first valve seat 223, the fuel flowing in from the inlet port 201 flows into the outlet port 203 via the first chamber 202, the communication passage 226, the pressure chamber 227, and the first fuel passage 222. Thus, the second shut-off valve 22 has a first valve 210 that, when opened by energization, allows fuel to flow from the upstream side to the downstream side of the second shut-off valve 22.

[0035] Then, as the first valve 210 moves in a direction that separates the first sealing member 213 from the first valve seat 223, the pin 214 of the first valve 210 strikes the wall surface 229 located in the axial direction of the elongated hole 225 of the second valve 220, in the direction of the opening of the first valve 210. As a result, an opening force Fop acts on the second valve 220 in the same direction as the movement of the first valve 210. This opening force Fop is an attractive force generated by the magnetic force of the electromagnetic coil 240 and acts in the direction that opens the second valve 220.

[0036] When the first valve 210 opens, the pressure chamber 227 and the outlet port 203 are connected, allowing fuel to flow from the upstream side to the downstream side of the second shut-off valve 22. As fuel flows from the upstream side to the downstream side of the second shut-off valve 22, the fuel pressure on the outlet port 203 side, which is the pressure on the downstream side of the second shut-off valve 22, increases, and the pressure difference between the inside of the pressure chamber 227 and the inside of the outlet port 203 decreases. Therefore, the resistance force Fcl, which is the force resisting the opening of the second valve 220, decreases. The resistance force Fcl includes the force acting on the second valve 220 in the closing direction, as well as the sliding resistance of the second valve 220 and the holder 250. Furthermore, the force acting on the second valve 220 in the closing direction includes the differential pressure load generated by the pressure difference between the inside of the pressure chamber 227 and the inside of the outlet port 203, and the biasing force of the spring 215.

[0037] When the differential pressure load decreases due to the opening of the first valve 210, and the valve opening force Fop becomes greater than the resistance force Fcl, the second valve 220 moves in a direction that separates the second sealing member 224 from the second valve seat 204. This movement of the second valve 220 causes the second valve 220 to open. The pressure downstream of the second shut-off valve 22 when the second valve 220 opens in this way is the first valve opening pressure Pa described above. This first valve opening pressure Pa is a value that is influenced by, for example, the attractive force of the electromagnetic coil 240 and the pressure-receiving area of ​​the second valve 220. When the second sealing member 224 separates from the second valve seat 204, the fuel that flowed in from the inlet port 201 flows mainly through the first chamber 202 to the outlet port 203.

[0038] When the second valve 220 is fully open, the end face 228 and the restricting portion 253 come into contact, stopping the axial movement of the second valve 220. The fuel that flows into the outlet port 203 is sent to the fuel injection valve 15 via the downstream piping 41 and the delivery pipe 60.

[0039] In this embodiment, the second valve opening pressure Pb is set to a lower pressure value than the second pressure P2, which is the pressure upstream of the second shut-off valve 22. Also, the first valve opening pressure Pa is set to a lower pressure value than the second valve opening pressure Pb. In other words, the relative magnitudes of the first valve opening pressure Pa, the second valve opening pressure Pb, and the second pressure P2 are "first valve opening pressure Pa < second valve opening pressure Pb < second pressure P2".

[0040] The second shut-off valve 22 has a second valve 220 that opens when the pressure downstream of the second shut-off valve 22 exceeds a predetermined first opening pressure Pa due to the inflow of fuel downstream of the second shut-off valve 22 caused by the opening of the first valve 210. In a second shut-off valve 22 having such a second valve 220, when the fuel pressure in the outlet port 203 increases and exceeds the first opening pressure Pa, the pressure difference between the pressure chamber 227 and the outlet port 203 decreases. In other words, the pressure difference between the upstream and downstream sides of the second valve 220 decreases, and the second valve 220 opens. Therefore, the magnetic force required to open the valve can be reduced compared to the case where the magnetic force of the electromagnetic coil is directly used to open the second valve 220. Consequently, for example, the electromagnetic coil 240 can be miniaturized.

[0041] <Closing operation of the second shut-off valve> When the current to the electromagnetic coil 240 is cut off, the biasing force of the spring 215 causes the first valve 210 to move in a direction that causes the first sealing member 213 to strike the first valve seat 223. This causes the first valve 210 to close.

[0042] When the first sealing member 213 contacts the first valve seat 223, the biasing force of the spring 215 acts on the second valve 220. As a result, the second valve 220 moves in the direction in which the second sealing member 224 contacts the second valve seat 204. This causes the second valve 220 to close.

[0043] <Operation of this embodiment> Figure 3 shows the operation of this embodiment. Figure 3(a) shows the transition of the downstream pressure, Figure 3(b) shows the transition of the open / closed state of the first valve 210, Figure 3(c) shows the transition of the open / closed state of the second valve 220, and Figure 3(d) shows the transition of the open / closed state of the downstream valve 90. The downstream pressure shown in Figure 3(a) is the fuel pressure in the fuel passage between the second shut-off valve 22 and the downstream valve 90.

[0044] When engine starting begins at time t1, the electromagnetic coil 240 is energized, causing the closed first valve 210 to open. This opening of the first valve 210 allows fuel to flow from the pressure chamber 227 to the outlet port 203, causing the downstream pressure to increase towards the second pressure P2.

[0045] At time t2, when the downstream pressure reaches the first valve opening pressure Pa, the second valve 220 opens. At time t3, when the downstream pressure reaches the second valve opening pressure Pb, the closed downstream valve 90 opens. Once the second valve 220 opens and the downstream valve 90 opens, fuel supply to the fuel injection valve 15 via the downstream piping 41 and delivery pipe 60 begins.

[0046] <Effects of this embodiment> (1) When the first valve 210 is opened by energization, the pressure on the downstream side of the second shut-off valve 22 increases due to the inflow of fuel downstream of the second shut-off valve 22. Here, the downstream valve 90, which is provided in the downstream piping 41 connected to the downstream side of the second shut-off valve 22, opens after the timing when the second valve 220 of the second shut-off valve 22 opens. That is, the downstream valve 90 remains closed at least until the second valve 220 of the second shut-off valve 22 opens.

[0047] When the downstream valve 90 is closed, the volume of the fuel passage between the second shut-off valve 22 and the downstream closed end of the second shut-off valve 22 is smaller than when the downstream valve 90 is open. The smaller the volume of the fuel passage, the faster the downstream pressure of the second shut-off valve 22 rises after the first valve 210 opens, thus shortening the time it takes for the downstream pressure of the second shut-off valve 22 to reach or exceed the first opening pressure Pa. Therefore, the time from when the second shut-off valve 22 is energized until the second valve 220 opens can be shortened.

[0048] (2) If there is a delay in the opening of the second valve 220 during engine starting, it may not be possible to secure a sufficient fuel flow rate necessary for engine starting, which could lead to a longer engine starting time. In this embodiment, however, the time from when the second shut-off valve 22 is energized until the second valve 220 opens is shortened, so the second valve 220 opens quickly during engine starting. Therefore, it is possible to suppress an increase in engine starting time.

[0049] (3) The downstream piping 41 is provided with a check valve, a downstream valve 90. This downstream valve 90 opens when the pressure in the fuel passage between the downstream valve 90 and the second shut-off valve 22 exceeds the second opening pressure Pb, allowing fuel to flow from the upstream side to the downstream side of the downstream valve 90. The second opening pressure Pb is set to a value within the range of being greater than or equal to the first opening pressure Pa at which the second valve 220 opens, and less than the pressure on the upstream side of the second shut-off valve 22.

[0050] Thus, the second opening pressure Pb, which is the pressure at which the downstream valve 90 opens, is greater than or equal to the first opening pressure Pa, which is the pressure at which the second valve 220 opens. Therefore, the downstream valve 90 opens after the second valve 220 opens. Consequently, a valve that opens after the timing of the second valve 220 opening can be provided in the fuel passage.

[0051] Furthermore, the second valve opening pressure Pb is less than the pressure upstream of the second shut-off valve 22. Therefore, after both the second valve 220 and the downstream valve 90 are opened, the downstream valve 90 can be kept open by the pressure upstream of the second shut-off valve 22.

[0052] <Example of changes> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0053] By making the second valve opening pressure Pb the same as the first valve opening pressure Pa, the downstream valve 90 may be opened immediately after the second valve 220 opens. As shown in Figures 4 and 5, the downstream valve 90 may be configured as a solenoid valve that is driven to open when the second valve 220 opens. In this case, the control device 100 may control the drive of the downstream valve 90, for example, as follows.

[0054] Figure 5 shows an example of the opening and closing control of the downstream valve 90 in this modified example. Figure 5(a) shows the transition of the downstream pressure, Figure 5(b) shows the transition of the open and closed state of the first valve 210, Figure 5(c) shows the transition of the open and closed state of the second valve 220, and Figure 5(d) shows the transition of the open and closed state of the downstream valve 90. The downstream pressure shown in Figure 5(a) is the same as the downstream pressure shown in Figure 3, and is the fuel pressure in the fuel passage between the second shut-off valve 22 and the downstream valve 90. In this modified example, the second pressure P2, which is the pressure upstream of the second shut-off valve 22 and is the fuel pressure after being reduced by the pressure reducing valve 30, is set to the first opening pressure Pa, but the first opening pressure Pa may be set to a pressure value lower than the second pressure P2.

[0055] The downstream valve 90 is, for example, a normally open solenoid valve that closes when energized. When engine starting begins at time t1, the second shut-off valve 22 is energized, causing the closed first valve 210 to open. This opening of the first valve 210 allows fuel to flow from the pressure chamber 227 to the outlet port 203, causing the downstream pressure to increase towards the second pressure P2.

[0056] Furthermore, at time t1, the control device 100 starts supplying power to the downstream valve 90. As a result, the downstream valve 90, which was in the open state before time t1, closes. At time t2, when the downstream pressure reaches the first valve opening pressure Pa, the second valve 220 opens. Upon detecting the opening of the second valve 220, the control device 100 stops the power supply to the downstream valve 90. As a result, the downstream valve 90, which was closed from time t1 onward, becomes open. When the downstream valve 90 opens, fuel supply to the fuel injection valve 15 via the downstream piping 41 and the delivery pipe 60 begins.

[0057] Furthermore, the opening of the second valve 220 can be detected as appropriate. For example, when the second valve 220, which was previously closed, opens, the actual current flowing through the electromagnetic coil 240 temporarily decreases. Therefore, if such a temporary decrease in the actual current is detected, it can be determined that the second valve 220 has opened. Also, when the second valve 220 is open, the downstream pressure, which is the fuel pressure in the fuel passage between the second shut-off valve 22 and the downstream valve 90, remains equal to the second pressure P2. Therefore, if this downstream pressure is detected, and the behavior of such downstream pressure is detected, it can also be determined that the second valve 220 has opened.

[0058] The fuel for the internal combustion engine 10 was hydrogen gas, a gaseous fuel, but other gaseous fuels, such as compressed natural gas, may also be used. • The fuel for the internal combustion engine 10 was a gaseous fuel, but a liquid fuel may also be used. [Explanation of Symbols]

[0059] 10...Internal combustion engine 20...Tank 21...First shut-off valve 22...Second shut-off valve 22...Second valve 30...Pressure reducing valve 40...Fuel piping 41...Downstream piping 60...Delivery pipe 90...Downstream valve 100...Control device 210...First valve 220...Second valve 300...Fuel supply system

Claims

1. A fuel supply device having a fuel passage for an internal combustion engine and a solenoid valve provided in the fuel passage, The solenoid valve has a first valve body that, when energized, opens to allow fuel to flow from the upstream side to the downstream side of the solenoid valve, and a second valve body that opens when the pressure on the downstream side of the solenoid valve exceeds a predetermined opening pressure due to the fuel inflow to the downstream side of the solenoid valve caused by the opening of the first valve body. The fuel passage connected downstream of the solenoid valve is equipped with a valve that opens after the timing at which the second valve body opens. A fuel supply system for an internal combustion engine.

2. The aforementioned valve opening pressure is defined as the first valve opening pressure. The valve is a check valve that opens when the pressure in the fuel passage between the valve and the solenoid valve exceeds the second opening pressure, thereby allowing fuel to flow from the upstream side to the downstream side of the valve. The second valve opening pressure is set to a value within the range of being greater than or equal to the first valve opening pressure and less than the pressure on the upstream side of the solenoid valve. A fuel supply device for an internal combustion engine according to claim 1.

3. The valve is a solenoid valve that is driven to open when the second valve body opens. A fuel supply device for an internal combustion engine according to claim 1.

Images