Control device of electromagnetic valve

Abstract

To suppress wear of an electromagnetic valve caused by opening / closing operations.SOLUTION: A second cutoff valve 22 includes a valve body, and an electromagnetic coil which opens the valve body when electricity is applied to the electromagnetic coil, and is provided in a fuel pipe 40 of an internal combustion engine 10. A control device 100 controls electric current supplied to the electromagnetic coil when opening the valve body. When a pressure difference between a pressure acting on the valve body in a valve closing direction and a pressure acting on the valve body in a valve opening direction is small, the control device 100 executes processing of reducing the electric current supplied to the electromagnetic coil compared to when the pressure difference is large.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a solenoid valve. [Background technology]

[0002] For example, Patent Document 1 discloses a fuel pipe for an internal combustion engine that includes a valve that allows and blocks the flow of fuel. [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] When a solenoid valve that opens a valve element by energizing an electromagnetic coil is used as the valve, it is desirable to reduce the current supplied to the electromagnetic coil when the valve is opened. [Means for solving the problem]

[0005] A solenoid valve control device that solves the above problem is a solenoid valve control device that is provided in a fluid flow path and includes a valve element and an electromagnetic coil that opens the valve element when current is applied. This control device has a processing circuit that controls the current supplied to the electromagnetic coil when the valve element is open. The processing circuit executes processing to reduce the current supplied to the electromagnetic coil when the pressure difference between the pressure acting on the valve element in a valve closing direction and the pressure acting on the valve element in a valve opening direction is small compared to when the pressure difference is large. [Effects of the Invention]

[0006] This solenoid valve control device can reduce the current supplied to the electromagnetic coil when the valve is open. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing an internal combustion engine, a fuel supply system, and a control device to which a control device for a solenoid valve according to one embodiment is applied. [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 cross-sectional view showing the structure of the second shutoff valve of the same embodiment. [Figure 4] FIG. 4 is a flowchart showing the procedure of the process executed by the control device of the embodiment. [Figure 5] FIG. 5 is a diagram showing the relationship between the differential pressure and the supplied current in this embodiment. [Figure 6] Figure 6 is a timing chart showing the operation of this embodiment, in which Figure 6(a) shows the change in the third pressure, Figure 6(b) shows the change in the differential pressure, and Figure 6(c) shows the change in the supply current. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of a control device for a solenoid valve 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 uses hydrogen gas, which is a fluid gaseous fuel, as fuel.

[0009] 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 300 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, and a delivery pipe 60.

[0010] 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 .

[0011] 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 that connects the tank 20 and the fuel injection valve 15, and are a fluid flow path. 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.

[0012] 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.

[0013] 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.

[0014] The second shutoff valve 22 is an electromagnetic valve provided in the fuel supply system of the internal combustion engine 10, and is disposed in the fuel piping 40 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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, and the second shutoff valve 22. 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] <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.

[0025] 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. Note that fuel pressure control is performed, for example, when the operating state of the internal combustion engine 10 transitions to an idle operating state.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] At time t3, for example, when the operating state of the internal combustion engine 10 shifts to a state where the engine load is higher than the idle operating state, and the request to execute fuel pressure control is eliminated, the second shutoff valve 22 is maintained in an open state. While the second shutoff valve 22 is open, fuel is supplied from the tank 20 to the delivery pipe 60, so that the third pressure P3 gradually increases toward the second pressure P2.

[0031] <Structure of the second shutoff valve> 3 shows the structure of second shutoff valve 22. In the following, the direction along the central axis L of plunger 211 provided in second shutoff valve 22 will be referred to as the axial direction. Also, the direction perpendicular to the axial direction will be referred to as the radial direction.

[0032] The second shutoff 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 has an inlet port 201 to which the fuel pipe 40 connected to the pressure reducing valve 30 is connected, and an outlet port 203 to which the fuel pipe 40 connected to the delivery pipe 60 is connected.

[0033] The inlet port 201 and the outlet port 203 communicate with each other via a first chamber 202 which is a space formed inside the housing 200 . The stator 230 is cylindrical and is provided within the housing 200 .

[0034] The electromagnetic coil 240 is provided on the outer periphery of the stator 230. The electromagnetic coil 240 opens the valve element when energized. The electromagnetic coil 240 is connected to a drive circuit 400 that supplies power. The drive circuit 400 adjusts the supply current Is, which is the current supplied to the electromagnetic coil 240 when the valve element of the second shutoff valve 22 is opened. The drive circuit 400 is connected to the control device 100. The control device 100 controls the supply current Is via the drive circuit 400. The greater the force biasing the valve element in the valve closing direction, the greater the value of the supply current Is required to open the valve element.

[0035] The drive circuit 400 detects an actual current Isr, which is an actual current value flowing through the electromagnetic coil 240, for the control device 100. Then, the drive circuit 400 outputs the detected value of the actual current Isr to the control device 100.

[0036] First valve 210, which is a first valve body, includes plunger 211 that moves in the axial direction within stator 230, and first seal member 213 that opens and closes first fuel passage 222 as plunger 211 moves.

[0037] One end of plunger 211 forms protrusion 212 that protrudes from stator 230. The first seal member 213 is provided at the tip of protrusion 212. Protrusion 212 also includes pin 214 that extends radially. Both ends of pin 214 protrude from the outer circumferential surface of protrusion 212.

[0038] The holder 250 has a cylindrical portion 251 that is coaxial with the central axis L. The inner peripheral surface of the cylindrical portion 251 faces the outer peripheral surface of the protruding portion 212 and is spaced apart from it. Second valve 220, which is a second valve body, is slidably housed on the inner circumferential surface of cylindrical portion 251. Second valve 220 is formed with hole 221, through which the outer circumferential surface of protrusion 212 of first valve 210 slides. Second valve 220 is formed with elongated hole 225, into which pin 214 is inserted and which allows movement of pin 214 in the axial direction.

[0039] The first fuel passage 222 extending in the axial direction is formed at the tip of the second valve 220. The first fuel passage 222 is connected to the outlet port 203 that constitutes the second fuel passage. The outlet port 203 is a fuel passage with a flow path cross-sectional area larger than that of the first fuel passage 222.

[0040] A second seal member 224 that opens and closes the outlet port 203 is provided at the tip of the second valve 220. More specifically, the second seal member 224 opens and closes a second valve seat 204 provided at one end of the outlet port 203.

[0041] A first valve seat 223 protruding toward the protrusion 212 is formed at the tip of the second valve 220, in which the first fuel passage 222 is formed. The first valve seat 223 is opened and closed by a first seal member 213, thereby opening and closing the first fuel passage 222. The first fuel passage 222 serves as a communication passage that connects a flow passage upstream of the second valve 220, which serves as a second valve body, with a flow passage downstream of the second valve 220. The flow passage upstream of the second valve 220 includes a pressure chamber 227 (described below), a communication passage 226 (described below), the first chamber 202, and the inlet port 201. The flow passage downstream of the second valve 220 is the outlet port 203. The first valve 210 serves as a first valve body that opens before the second valve 220 opens and closes the first fuel passage 222.

[0042] In the hole 221, the space surrounded by the wall surface around the first valve seat 223 and the tip surface of the protrusion 212 serves as a pressure chamber 227 to which pressure acts to urge the second valve 220 in the valve closing direction. This pressure chamber 227 is connected to the first chamber 202 via a communication passage 226.

[0043] A second chamber 255 is formed on the inner peripheral surface side of a cylindrical portion 251 of the holder 250, and is a space for ensuring the stroke amount of the second valve 220 in the axial direction. End face 228 of second valve 220 opposite the side on which second seal member 224 is disposed and restriction portion 253, which is formed by the surface of holder 250 facing end face 228, come into contact with each other when second valve 220 is in the fully open state. By maintaining the abutting state between end face 228 and restriction portion 253, the position of the valve element when second valve 220 is in the fully open state is stabilized.

[0044] An end cap 280 that closes the end opposite to the side where plunger 211 is inserted is provided inside stator 230. A third chamber 257, which is a space, is formed between end cap 280 and plunger 211. In addition, a spring 215 that urges plunger 211 in a direction away from end cap 280 is provided between end cap 280 and plunger 211.

[0045] <Opening and closing operation of the second shutoff valve> When the electromagnetic coil 240 is energized, the plunger 211 is drawn into the stator 230, and the first valve 210 moves in a direction in which the first seal member 213 moves away from the first valve seat 223, thereby opening the first valve 210. When the first seal member 213 moves away from the first valve seat 223, the fuel that has flowed 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.

[0046] As a result of first valve 210 moving in a direction in which first seal member 213 moves away from first valve seat 223, pin 214 of first valve 210 comes into contact with wall surface 229 that is located in the valve opening direction of first valve 210 in the axial direction of elongated hole 225 of second valve 220. Therefore, a valve opening force Fop acting in the same direction as the movement direction of first valve 210 is applied to second valve 220. This valve opening force Fop is an attractive force generated by the magnetic force of electromagnetic coil 240, and acts in the direction in which second valve 220 opens.

[0047] When first valve 210 opens, pressure chamber 227 and outlet port 203 communicate with each other, reducing the pressure difference between pressure chamber 227 and outlet port 203. This reduces drag Fcl, which is a force resisting the opening of second valve 220. Note that drag Fcl includes a force acting in the closing direction of second valve 220, the sliding resistance of second valve 220 and holder 250, and the like. The force acting in the closing direction of second valve 220 includes a differential pressure load generated by the pressure difference between pressure chamber 227 and outlet port 203, and the biasing force of spring 215.

[0048] When the valve-opening force Fop becomes larger than the resistance force Fcl, the second valve 220 moves in a direction in which the second seal member 224 moves away from the second valve seat 204, thereby opening the second valve 220. When the second seal member 224 moves away from the second valve seat 204, the fuel that has flowed in from the inlet port 201 flows mainly into the outlet port 203 via the first chamber 202.

[0049] When the second valve 220 is in a fully open state, the end face 228 and the restricting portion 253 come into contact with each other, thereby stopping the movement of the second valve 220 in the axial direction. The fuel that has flowed into the outlet port 203 is sent to the fuel injection valve 15 via the fuel pipe 40 and the delivery pipe 60 .

[0050] When the supply of electricity to the electromagnetic coil 240 is stopped, the biasing force of the spring 215 or the like moves the first valve 210 in a direction in which the first seal member 213 abuts against the first valve seat 223. This causes the first valve 210 to close.

[0051] When first seal member 213 abuts against first valve seat 223, the biasing force of spring 215 acts on second valve 220. As a result, second valve 220 moves in the direction in which second seal member 224 abuts against second valve seat 204. This causes second valve 220 to close.

[0052] In this way, in the second shutoff valve 22, the second valve 220, which opens and closes the outlet port 203, which has a larger flow path cross-sectional area than the first fuel passage 222, is opened using the pressure in the pressure chamber 227. Therefore, compared to when the magnetic force of an electromagnetic coil is directly used to open the second valve 220, the magnetic force required to open the valve can be made smaller, and the electromagnetic coil 240 can be made smaller.

[0053] Furthermore, in the second shutoff valve 22, a small flow rate of fuel is adjusted using the first valve 210. Therefore, the above-described fuel pressure control is performed by driving the first valve 210 to open and close. Furthermore, in an operating state where the engine load is higher than in an idling operating state, the second valve 220 is opened.

[0054] <Supply current control> FIG. 4 shows the procedure of the process executed by the control device 100 to control the supply current Is described above. The process shown in FIG. 4 is implemented by the CPU 110 executing a program stored in the memory 120 of the control device 100. Execution of the process shown in FIG. 4 is initiated when there is a request to open the second valve 220. Incidentally, a request to open the second valve 220 is made, for example, when the engine is started. Note that, hereinafter, step numbers are represented by numbers preceded by "S."

[0055] When this process starts, the control device 100 starts supplying current to the electromagnetic coil 240 (S100). In the process of S100, the control device 100 substitutes an initial current Iss for the supply current Is. The initial current Iss is a preset maximum value of the supply current Is required to open the first valve 210 and the second valve 220. Then, when the initial current Iss is substituted for the supply current Is, the control device 100 controls the drive circuit 400 so that the initial current Iss is supplied to the electromagnetic coil 240.

[0056] Next, the control device 100 determines whether the first valve 210 is opened (S110). The valve open determination in the processing of S110 can be performed as appropriate. For example, when the first valve 210 is opened, fuel is supplied to the delivery pipe 60, causing a change in the third pressure P3. Therefore, if a change in the third pressure P3 is detected after the processing of S100 is executed, it can be determined that the first valve 210 is opened.

[0057] Then, the control device 100 repeatedly executes the process of S110 until a positive determination is made in the process of S110. If it is determined in the process of S110 that the first valve 210 is opened (S110: YES), the control device 100 acquires the third pressure P3 (S120).

[0058] Next, the control device 100 calculates the differential pressure ΔP (S130). The control device 100 substitutes the value obtained by subtracting the second pressure P2 from the acquired third pressure P3 into the differential pressure ΔP. The second pressure P2 is the fuel pressure after being reduced by the pressure reducing valve 30, and is a preset value. The second pressure P2 is a pressure that acts on the second valve 220 in a valve closing direction, and the third pressure P3 is a pressure that acts on the second valve 220 in a valve opening direction.

[0059] Next, the control device 100 executes a process of adjusting the supply current Is based on the differential pressure ΔP (S140). In S140, the control device 100 sets the supply current Is based on the differential pressure ΔP.

[0060] 5, when the differential pressure ΔP is small, the control device 100 sets the supply current Is so that the value of the supply current Is is smaller than when the differential pressure ΔP is large. The setting of this supply current Is is performed based on a set map stored in the memory 120, for example, that shows the correspondence relationship between the differential pressure ΔP and the supply current Is. Once the supply current Is is set, the control device 100 controls the drive circuit 400 so that the set supply current Is is supplied to the electromagnetic coil 240. The processing of S140 is processing to reduce the current supplied to the electromagnetic coil when the differential pressure between the pressure acting on the valve disc in the valve closing direction and the pressure acting on the valve disc in the valve opening direction is small, compared to when the differential pressure is large.

[0061] Next, the control device 100 determines whether the second valve 220 is fully open (S150). The full-open determination in the process of S150 can be performed as appropriate. For example, when the second valve 220 is fully open, the actual current Isr flowing through the electromagnetic coil 240 temporarily decreases. Therefore, if a temporary decrease in the actual current Isr is detected, it can be determined that the second valve 220 is fully open. Furthermore, when the second valve 220 is fully open, the third pressure P3 is maintained at a state equal to the second pressure P2. Therefore, if such behavior of the third pressure P3 is detected, it can be determined that the second valve 220 is fully open.

[0062] Then, the control device 100 repeatedly executes the processes of S120, S130, S140, and S150 until a positive determination is made in the process of S150. If the determination in the process of S150 is affirmative (S150: YES), the control device 100 maintains the current supply current Is and ends this process.

[0063] <Operation of this embodiment> Figure 6 shows the changes in each value when the second valve 220 is opened. Figure 6(a) shows the change in the third pressure P3, Figure 6(b) shows the change in the differential pressure ΔP, and Figure 6(c) shows the change in the supply current Is.

[0064] When a request to start the engine is made at time t1, an initial current Iss is supplied to the electromagnetic coil 240. Note that the third pressure P3 before time t1 is the fuel pressure when the engine is stopped. Incidentally, the fuel pressure when the engine is stopped is often the fuel pressure when the engine is stopped, for example, the fuel pressure during idling. Therefore, the third pressure P3 before time t1 is often a pressure close to, for example, the target pressure Pt.

[0065] After the initial current Iss is supplied to the electromagnetic coil 240, when the first valve 210 opens at time t2, fuel flows from the inlet port 201 to the outlet port 203 via the first fuel passage 222 etc. Therefore, the third pressure P3, which is the pressure on the outlet port 203 side, gradually increases over time.

[0066] As the third pressure P3 increases, the differential pressure ΔP gradually decreases. Therefore, after time t2, the supply current Is gradually decreases from the initial current Iss. At time t3, when the second valve 220 is fully opened, the supply current Is at that time is maintained. Also, the third pressure P3 becomes equal to the second pressure P2.

[0067] <Effects of this embodiment> (1) When the pressure difference ΔP between the pressure acting on the second valve 220 in the valve closing direction and the pressure acting on the second valve 220 in the valve opening direction is small, the force pressing the second valve 220 in the valve closing direction is smaller than when the pressure difference ΔP is large. Therefore, the attraction force of the electromagnetic coil 240 required to open the second valve 220 can be reduced by the amount that the resistance Fcl generated by the pressure difference between the pressure chamber 227 and the outlet port 203, that is, the resistance corresponding to the differential pressure load generated by the pressure difference ΔP, is reduced. Therefore, when the pressure difference ΔP is small, the second valve 220 opens even if the current supplied to the electromagnetic coil 240 is reduced. Therefore, in the process of S140 shown in FIG. 4 , when opening the second valve 220, the control device 100 executes a process to reduce the current supplied to the electromagnetic coil 240 when the pressure difference ΔP is small. Therefore, compared to when the current supplied to the electromagnetic coil 240 is kept constant, the current supplied to the electromagnetic coil 240 when the second valve 220 is open can be reduced.

[0068] (2) When second valve 220 is opened, the current supplied to electromagnetic coil 240 is reduced, thereby reducing the attractive force of electromagnetic coil 240. When the attractive force of electromagnetic coil 240 is reduced, the impact speed between end face 228 and restriction portion 253 decreases when second valve 220 is fully open. Therefore, the valve-opening sound generated by the contact between end face 228 and restriction portion 253 can be reduced.

[0069] (3) Furthermore, when the attractive force of the electromagnetic coil 240 is reduced, the collision load when the end face 228 and the restricting portion 253 come into contact with each other when the second valve 220 is fully open is reduced. Therefore, wear of the end face 228 and the restricting portion 253 due to the contact can be suppressed.

[0070] (4) Since the current supplied to the electromagnetic coil 240 is reduced, heat generation in the electromagnetic coil 240 due to current flow can be suppressed. (5) Heat generation in the electromagnetic coil 240 due to energization is suppressed, so the life of the electromagnetic coil 240 can be extended.

[0071] (6) Second shutoff valve 22 has first fuel passage 222, which is a communication passage that connects a passage upstream of second valve 220 with a passage downstream of second valve 220. Second shutoff valve 22 also has first valve 210 that opens before second valve 220 opens and closes first fuel passage 222.

[0072] With this configuration, before second valve 220 opens, the flow path upstream of second valve 220 and the flow path downstream of second valve 220 are connected to each other. Therefore, the pressure difference ΔP between the pressure acting on second valve 220 in the valve closing direction and the pressure acting on second valve 220 in the valve opening direction becomes small. Therefore, the current supplied to electromagnetic coil 240 can be made smaller than in a case where first fuel passage 222 and first valve 210 are not provided.

[0073] <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.

[0074] The second shutoff valve 22 does not have to include the first valve 210. In this case, the second valve 220 may be directly driven to open and close by the electromagnetic coil 240. Although the second shutoff valve 22 is a solenoid valve that is applied to the fuel pressure control described above, it does not have to be applied to such fuel pressure control. For example, the second shutoff valve 22 may be controlled to be held in an open state while the engine is running, and to be held in a closed state while the engine is stopped.

[0075] The supply current Is based on the differential pressure ΔP is set based on a map. Alternatively, the attractive force of the electromagnetic coil 240 required to open the second valve 220 is calculated based on the differential pressure ΔP. The supply current Is that provides the calculated attractive force may then be found from a predetermined map.

[0076] The current supplied to the electromagnetic coil 240 can be reduced when the second valve 220 is open. This reduces the power consumption of the electromagnetic coil 240. Therefore, when the internal combustion engine 10 and an electric motor are provided as the drive source of a vehicle, the following effects can be obtained. That is, the power consumption of the battery that drives the electric motor is reduced, thereby extending the cruising range in a driving mode using the electric motor. Furthermore, the operation of the internal combustion engine to charge the battery can be reduced, thereby reducing the fuel consumption for charging the battery.

[0077] 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. The fuel used in the internal combustion engine 10 is gaseous fuel, but it may be liquid fuel.

[0078] The fluid flow path is the fuel passage of the internal combustion engine 10, but may be another flow path. 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]

[0079] 10...Internal combustion engine 15...Fuel injection valve 20...Tank 22...Second shutoff valve 30...Reducing valve 83...Third pressure sensor 100...Control device 201...inlet port 203...Exit port 204...Second valve seat 210...First valve 211...plunger 212...Protruding part 213...first seal member 214...pin 220...Second valve 221...hole 222…1st fuel passage 223...First valve seat 224...Second seal member 227...Pressure chamber 230...Stator 240...Electromagnetic coil 250...Holder 251...Cylinder part

Claims

1. A control device for an electromagnetic valve provided in a fluid flow path, the control device comprising: a valve body; and an electromagnetic coil that opens the valve body when energized, a processing circuit that controls the current supplied to the electromagnetic coil when the valve body is opened; The processing circuit executes a process to reduce the current supplied to the electromagnetic coil when a pressure difference between a pressure acting on the valve body in a valve closing direction and a pressure acting on the valve body in a valve opening direction is small, compared to when the pressure difference is large. Solenoid valve control device.

2. When the valve body is a first valve body, The solenoid valve is a communication passage that communicates a flow passage upstream of the first valve body with a flow passage downstream of the first valve body; and a second valve body that opens prior to the opening of the first valve body and opens and closes the communication passage. The solenoid valve control device according to claim 1 .

3. The fluid flow path is a fuel passage of an internal combustion engine. The solenoid valve control device according to claim 1 .

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