JP5989406B2 - Fuel pressure control device - Google Patents

Description

  The present invention relates to a fuel pressure control device, and more particularly to a fuel pressure control device that controls the pressure of fuel supplied to a fuel injection valve of an internal combustion engine mounted on a vehicle or the like.

  Conventionally, as this type of fuel pressure control device, an electric fuel pump that supplies fuel to an internal combustion engine through a fuel supply passage, and a pressure of fuel supplied to the internal combustion engine (hereinafter simply referred to as fuel pressure) are predetermined. A fuel pressure regulator that adjusts to a pressure and an ECU that detects the operating state of the internal combustion engine and controls the driving of the fuel pump based on the detected operating state are known (see, for example, Patent Document 1). . More specifically, when the ECU of the fuel pressure control device detects that the operating state of the internal combustion engine is in a low rotation and low load operating state, the fuel pressure is lower than a predetermined pressure adjusted by the fuel pressure regulator. Thus, the applied voltage of the fuel pump is controlled. As a result, the fuel pressure can already be reduced when the internal combustion engine is stopped, so that fuel leakage from the injector when the internal combustion engine is stopped can be suppressed without consuming excess power.

  By the way, in reducing the power consumption of such a fuel pump, it is desirable to reduce the applied voltage of the fuel pump as much as possible. However, if the applied voltage of the fuel pump is lowered too much, foreign matter contained in the fuel may be caught in the sliding portion of the fuel pump, which may cause a load on the electric pump. Such a load due to foreign object biting is a factor that impairs the original discharge performance of the electric pump.

  For this reason, such a fuel pump has a restriction that the applied voltage must be equal to or higher than a predetermined lower limit voltage so that the original discharge performance can be exhibited even when foreign matter biting occurs as described above. Therefore, the fuel pump is not driven at an applied voltage lower than a predetermined lower limit voltage, and can exhibit its original discharge performance even if there is a slight foreign matter bite.

  However, in such a fuel pump, since the drive region is a region equal to or higher than a predetermined lower limit voltage, the fuel discharge amount is limited to the minimum fuel discharge amount corresponding to the predetermined lower limit voltage. Such a fuel pump cannot realize a fuel discharge amount lower than the minimum fuel discharge amount. Therefore, in the fuel pressure control device provided with such a fuel pump, there is a problem that the fuel injection amount injected from the fuel injection valve cannot be less than the minimum fuel discharge amount corresponding to the lower limit voltage.

  Therefore, in order to solve these problems, a reduction valve is provided on the branch passage branched from the fuel supply passage, in addition to the fuel pressure regulator, so that the fuel consumption consumed in the internal combustion engine is the lowest fuel discharge that can be discharged by the fuel pump. When the amount is less than the amount, a configuration in which the fuel in the fuel supply passage is returned to the fuel tank through the branch passage by opening the reduction valve is conceivable. If such a reduction valve is provided, the fuel consumption can be made less than the minimum fuel discharge amount corresponding to the lower limit voltage.

  Here, as the above-described reduction valve, for example, a so-called normally open type electromagnetic valve that is normally opened and closed by a drive signal is conceivable. In particular, by adopting such a normally open type reduction valve, it is only necessary to energize and close the reduction valve only when necessary, for example, when starting an internal combustion engine. As a result, fuel efficiency is improved.

JP 2001-207928 A

  However, when a normally open type solenoid valve is employed as the weight reducing valve as described above, the following problems arise. That is, if the energization of the reduction valve is released when the internal combustion engine is stopped, the reduction valve is opened and the fuel pressure in the fuel supply passage cannot be maintained. Therefore, in such a reduction valve, in order to maintain the fuel pressure when the operation of the internal combustion engine is stopped, energization to the reduction valve must be maintained. For this reason, there is a problem that power consumption cannot be suppressed, and as a result, fuel consumption cannot be improved.

  The present invention has been made to solve the above-described problems, and a normally open solenoid valve is used as a reduction valve for controlling the fuel consumption to be less than the minimum fuel discharge amount of the electric fuel pump. It is an object of the present invention to provide a fuel pressure control device that can maintain the fuel pressure when the internal combustion engine is stopped while suppressing power consumption even if it is adopted.

In order to achieve the above object, the fuel pressure control device according to the present invention is (1) an electric motor that pumps fuel stored in a fuel tank to a delivery pipe to which a fuel injection valve of an internal combustion engine is connected via a supply passage. A fuel pump of the type, a return passage branched from the supply passage and flowing back through the supply passage to the fuel tank, and provided in the return passage, closed by energization, A reduction valve composed of a normally open solenoid valve that opens when released, and between the return pipe, the branch part of the supply path, and the delivery pipe, from the delivery pipe side a check valve for preventing backflow of fuel to the fuel tank side is provided, the fuel pump is a lower limit voltage higher than the applied voltage that can keep the drive even when biting foreign matter on the sliding portions The reduction valve is configured to be operated, and a request required for the internal combustion engine according to a fuel discharge amount of the fuel pump when the fuel pump is driven at the lower limit voltage and an operating state of the internal combustion engine It has a function as a control valve for returning the difference fuel from the fuel consumption to the fuel tank, is connected to the supply passage on the delivery pipe side with respect to the return passage, and communicates the supply passage with the fuel tank. And a relief valve that is provided in the relief passage and opens when the pressure of the fuel flowing in the supply passage reaches a predetermined pressure, and the check valve includes the supply passage And a branch portion of the relief passage, and a portion provided between the return passage and the branch portion of the supply passage .

  With this configuration, the fuel pressure control device according to the present invention has the check valve provided between the return passage provided with the reduction valve, the branch portion of the supply passage, and the delivery pipe. Even if energization of the weight reduction valve configured by a normally open solenoid valve is released, the pressure of the fuel in the supply passage (hereinafter referred to as fuel pressure) can be maintained by the check valve. For this reason, it is not necessary to maintain power supply to the reduction valve in order to maintain the fuel pressure when the operation of the internal combustion engine is stopped, and it is sufficient to supply power only when necessary, for example, when starting the internal combustion engine. Can contribute to improving fuel efficiency. As described above, the fuel pressure control device according to the present invention is a case where a normally open solenoid valve is employed as a reduction valve for controlling the fuel consumption to be less than the minimum fuel discharge amount of the electric fuel pump. However, it is possible to maintain the fuel pressure when the internal combustion engine is stopped while suppressing the power consumption.

  With this configuration, the fuel pressure control device according to the present invention can prevent the fuel pump from being stopped due to foreign object biting because the fuel pump is driven at an applied voltage that is equal to or higher than the lower limit voltage. Further, since the reduction valve functions as a control valve for returning the difference fuel between the fuel discharge amount of the fuel pump and the required fuel consumption when the fuel pump is driven at the lower limit voltage to the fuel tank, the applied voltage of the fuel pump The required fuel consumption can be made less than the minimum fuel discharge amount corresponding to the lower limit voltage while maintaining the above the lower limit voltage. Therefore, excessive fuel consumption can be suppressed, and fuel consumption can be improved.

  With this configuration, the fuel pressure control device according to the present invention has the check valve provided between the branch portion of the supply passage and the relief passage, and the branch portion of the return passage and the supply passage. The fuel pressure in the passage can be controlled below a predetermined pressure. Here, the predetermined pressure that is the valve opening pressure of the relief valve is set to a pressure for preventing an abnormal increase in the fuel pressure in the supply passage.

  According to the present invention, even when a normally open solenoid valve is used as a reduction valve for controlling the fuel consumption to be less than the minimum fuel discharge amount of the electric fuel pump, the power consumption is suppressed. However, it is possible to provide a fuel pressure control device that can maintain the fuel pressure when the internal combustion engine is stopped.

1 is a schematic configuration diagram of a vehicle to which a fuel pressure control device according to an embodiment of the present invention is applied. It is the schematic of the weight reduction valve which concerns on embodiment of this invention, Comprising: (a) is a valve opening state, (b) is a figure which shows a valve closing state.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the vehicle 1 includes an engine 10, a fuel supply mechanism 20, and an ECU (Electronic Control Unit) 100.

  The engine 10 is configured as an internal combustion engine that can output power using a hydrocarbon-based fuel such as gasoline or light oil. The fuel used for the engine 10 may be an alcohol fuel obtained by mixing alcohol such as ethanol and gasoline.

  In the present embodiment, the engine 10 is constituted by a so-called in-line 4-cylinder gasoline engine in which four cylinders 11 are arranged in series as indicated by # 1, # 2, # 3, and # 4. The engine 10 is not limited to an in-line four-cylinder engine, and is configured by various types of engines such as an in-line six-cylinder engine, a V-type six-cylinder engine, a V-type 12-cylinder engine, or a horizontally opposed six-cylinder engine. Also good.

  Further, in the present embodiment, the engine 10 is constituted by a four-cycle gasoline engine that performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while a piston (not shown) reciprocates twice. Explain that it is.

  Furthermore, each of the four cylinders 11 indicated by # 1, # 2, # 3, and # 4 in the engine 10 is provided with an intake port 12 respectively. The engine 10 also includes a port injector 13 for injecting fuel into the intake port 12.

  The port injector 13 includes a solenoid coil controlled by an injection command signal Iq from the ECU 100, a needle valve, and a nozzle part. The port injector 13 is supplied with fuel at a predetermined pressure. When the solenoid coil is energized by the ECU 100, the port injector 13 opens the needle valve and injects fuel into the intake port 12. The port injector 13 in the present embodiment constitutes a fuel injection valve according to the present invention.

  The fuel supply mechanism 20 includes a fuel pump 21 that pressurizes and pumps fuel from the fuel tank 30, and a delivery pipe 23 that introduces the fuel pumped by the fuel pump 21 through the fuel pipe 22. A supply passage 22 a for supplying fuel from the fuel pump 21 to the delivery pipe 23 is formed in the fuel pipe 22.

  With this configuration, the fuel supply mechanism 20 supplies fuel to the plurality of port injectors 13 that respectively inject fuel into the plurality of intake ports 12 corresponding to the plurality of cylinders 11 in the intake passage 15 of the engine 10. It has become.

  The fuel pump 21 is an electric fuel pump that is driven in accordance with a control signal output from the ECU 100. The fuel pump 21 pumps up the fuel stored in the fuel tank 30 and passes it through a supply passage 22 a in the fuel pipe 22. Thus, the pressure is fed to the delivery pipe 23 to which the port injector 13 is connected.

  Specifically, the fuel pump 21 includes a motor whose rotational speed changes according to an applied voltage corresponding to a control signal output from the ECU 100, and an impeller that rotates by the rotational force of the motor. The fuel pump 21 pressurizes and pumps fuel from the fuel tank 30 by rotating the impeller. Therefore, in the fuel pump 21, the rotational force of the motor is adjusted according to the magnitude of the applied voltage applied to the motor, and the fuel discharge amount of the discharged fuel is variable.

  In addition, the fuel pump 21 is an integrated filter that has both a function of a suction filter that removes relatively large foreign matters contained in the fuel and a function of a fuel filter that removes relatively small foreign matters and motor foreign matters contained in the fuel. I have.

  The delivery pipe 23 is connected to the fuel pipe 22 at one end side in the series arrangement direction of the plurality of cylinders 11 and is configured to supply fuel to the plurality of port injectors 13 independently. The delivery pipe 23 is provided with a fuel pressure sensor 25 that detects the pressure of the fuel in the delivery pipe 23 (hereinafter referred to as fuel pressure).

  The fuel supply mechanism 20 includes a relief pipe 26 that returns a part of the fuel branched from the fuel pipe 22 and flowing through the fuel pipe 22 to the fuel tank 30, and a return pipe 27.

  The relief pipe 26 is connected to the fuel pipe 22 on the delivery pipe 23 side of the return pipe 27, and a relief passage 26a that connects the supply passage 22a and the fuel tank 30 is formed inside.

  The relief pipe 26 is provided with a relief valve 28 that returns fuel from the fuel pipe 22 to the fuel tank 30 when the fuel pressure of the fuel pipe 22 exceeds a predetermined fuel pressure (for example, several hundred kPa). ing. That is, the relief valve 28 opens when the fuel pressure in the supply passage 22a reaches a predetermined pressure. The relief valve 28 is provided to prevent an abnormal increase in the fuel pressure of the fuel pipe 22. Therefore, the predetermined pressure, which is the valve opening pressure of the relief valve 28, is set to a pressure (for example, 600 kPa) for preventing an abnormal increase in the fuel pressure in the supply passage 22a.

  The return pipe 27 is formed therein with a return passage 27a that branches from the supply passage 22a and returns a part of the fuel flowing through the supply passage 22a to the fuel tank 30.

  The return pipe 27 is provided with a reduction valve 29 constituted by a so-called normal open type electromagnetic valve that closes when energized and opens when deenergized.

  Specifically, as shown in FIG. 2A, the reduction valve 29 includes an electromagnetic solenoid 29a, a valve body 29b, and a coil spring 29c. When the electromagnetic solenoid 29a is not energized, that is, when the energization is released, the reducing valve 29 is energized in the valve opening direction (downward in the figure) by the energizing force of the coil spring 29c. The state is to be maintained. As a result, the return passage 27a is in a communication state, and the fuel flowing into the reduction valve 29 flows toward the fuel tank 30 through the communication hole 29d formed in the valve body 29b. That is, when the reduction valve 29 is opened, a part of the fuel flowing in the fuel pipe 22, for example, surplus fuel as will be described later, enters the fuel tank 30 (see FIG. 1) via the return passage 27a. Returned.

  On the other hand, as shown in FIG. 2B, when the solenoid valve 29a is energized in response to a command signal from the ECU 100, the valve 29b is closed against the urging force of the coil spring 29c. It moves in the direction (upward in the figure), and the valve is closed. As a result, the return passage 27a enters a non-communication state.

  Further, as shown in FIG. 1, the fuel supply mechanism 20 is provided with a check valve 40 on the supply passage 22 a between the supply passage 22 a and the branch portion 42 of the return passage 27 a and the delivery pipe 23. .

  More specifically, the check valve 40 is provided between the branch portion 41 and the branch portion 42 of the supply passage 22a and the relief passage 26a.

  The check valve 40 is configured to prevent the backflow of fuel from the delivery pipe 23 side to the fuel tank 30 side in the supply passage 22a. The operation of the check valve 40 will be described later.

  The ECU 100 includes, for example, a microcomputer including a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and performs signal processing according to a program stored in advance in the ROM. It is like that. Various control constants and various maps are stored in advance in the ROM.

  The ECU 100 is connected to various sensors such as the fuel pressure sensor 25, the rotation speed sensor 101, the intake air amount sensor 102, and the accelerator opening sensor 103, the port injector 13, the fuel pump 21, and the reduction valve 29. ing.

  The fuel pressure sensor 25 detects the fuel pressure in the delivery pipe 23. The rotational speed sensor 101 detects the engine rotational speed Ne of the engine 10. The intake air amount sensor 102 detects the intake air amount GA. The accelerator opening sensor 103 detects an accelerator operation amount ACC corresponding to the depression amount of the accelerator pedal. Each of these sensors transmits a signal corresponding to the detection result to the ECU 100.

  The ECU 100 executes various calculations based on signals input from these various sensors, and executes various controls based on the calculation results.

  For example, the ECU 100 calculates the target fuel injection amount Q based on the intake air amount GA, the engine rotational speed Ne, the accelerator operation amount ACC, and the like. The ECU 100 sets a valve opening period of the port injector 13, that is, an injection period based on the fuel pressure so that the calculated target fuel injection amount Q can be realized. ECU 100 individually outputs a valve opening command to each port injector 13 according to the set injection period. As a result, an amount of fuel commensurate with the operating state of the engine 10 is injected from each port injector 13. At this time, the ECU 100 controls the applied voltage applied to the fuel pump 21 so as to adjust the fuel discharge amount of the fuel pump 21 so that fuel for the target fuel injection amount Q is injected from the port injector 13. It has become.

  In addition, the ECU 100 applies an applied voltage to the fuel pump 21 in accordance with the target fuel pressure so that the minimum discharge capacity necessary for securing the target fuel pressure (hereinafter referred to as the target fuel pressure) is obtained. To control. Here, the target fuel pressure is an optimum fuel pressure according to, for example, the operating state of the engine 10 and the fuel injection amount.

  More specifically, the ECU 100 controls the applied voltage at a predetermined lower limit voltage Vmin or higher. The predetermined lower limit voltage Vmin generates a driving torque capable of maintaining the driving of the fuel pump 21 even if foreign matter is caught in a sliding portion of the fuel pump 21, for example, a gap portion between the impeller and the pump cover. The voltage that can be used. That is, the fuel pump 21 is driven with an applied voltage that is equal to or higher than the lower limit voltage Vmin that can maintain driving even when foreign matter is caught in the sliding portion. Therefore, it is possible to prevent the fuel pump 21 from being stopped due to the above-mentioned foreign matter being caught.

  Here, since the fuel pump 21 is limited by the above-described lower limit voltage Vmin, it cannot be driven with an applied voltage lower than the lower limit voltage Vmin. In this case, the minimum fuel discharge amount of the fuel pump 21 is a fuel discharge amount corresponding to the lower limit voltage Vmin. Therefore, the fuel pump 21 cannot discharge fuel with a fuel discharge amount less than the minimum fuel discharge amount according to the lower limit voltage Vmin. For this reason, for example, when the required fuel consumption (required fuel consumption) is small, such as during idle operation, the above-mentioned minimum fuel discharge amount becomes large with respect to the required fuel consumption. There is a problem that the required fuel consumption cannot be obtained. The required fuel consumption here is, for example, the fuel consumption consumed by the engine 10 to obtain the target fuel injection amount Q.

  As a result, the actual fuel pressure in the delivery pipe 23 (hereinafter referred to as the actual fuel pressure) also rises above the target fuel pressure, and the actual fuel pressure cannot be maintained at the target fuel pressure.

  Therefore, in the present embodiment, the above-described reduction valve 29 is provided in the fuel injection mechanism 20 in order to solve such a problem. Thus, when there is a difference fuel between the minimum fuel discharge amount when the fuel pump 21 is driven at the lower limit voltage Vmin and the required fuel consumption amount that is required according to the operating state of the engine 10, the reduction valve 29 By opening the valve, the differential fuel can be returned to the fuel tank 30. Thus, the weight reduction valve 29 has a function as a control valve.

  Next, with reference to FIG. 1 and FIG. 2, the operation of the reducing valve 29 and the check valve 40 according to the present embodiment will be described.

  When the engine 10 is in a normal operation state other than when the operation is stopped or started, the reduction valve 29 is maintained in the open state by the urging force of the coil spring 29c because the electromagnetic solenoid 29a is not energized. ing. At this time, the fuel discharge amount discharged from the fuel pump 21 is set to a discharge amount in consideration of the fuel amount returned to the fuel tank 30 via the reduction valve 29.

  Here, when the engine 10 enters, for example, an idle operation state, the applied voltage of the fuel pump 21 is lowered to the lower limit voltage Vmin so as to reduce the fuel supplied to the engine 10 so that the fuel discharge amount becomes the minimum amount. At this time, the required fuel consumption required for the engine 10 in the idle operation state is lower than the minimum fuel discharge amount corresponding to the lower limit voltage Vmin of the fuel pump 21. In the present embodiment, even in such a case, since the reduction valve 29 is in the open state, the difference fuel between the minimum fuel discharge amount and the required fuel consumption amount causes the return passage 27a and the reduction valve 29 to be opened. To the fuel tank 30. Thereby, the fuel consumption consumed by the engine 10 can be set to a desired required fuel consumption.

  Next, when the engine 10 is stopped from the normal operation state, the drive of the fuel pump 21 is also stopped, so that the fuel pressure in the supply passage 22a is lowered. At this time, in the present embodiment, the check valve 40 is closed, and the fuel pressure in the supply passage 22a after the operation of the engine 10 is stopped is maintained. Here, since the check valve 40 is provided on the delivery pipe 23 side, that is, on the downstream side in the fuel supply direction with respect to the branching portion 42, the fuel pressure is reduced by the reduction valve 29 opened when the engine 10 is stopped. Is prevented. Thereby, the fuel pressure is maintained at the fuel pressure when the operation of the engine 10 is stopped. Therefore, at the next start, the fuel pressure can be quickly raised to the target fuel pressure.

  With respect to these operation states and operation stop states, the reduction valve 29 is closed when the engine 10 is started. Specifically, the ECU 100 detects an engine start request based on, for example, an ignition switch or a starter ON signal, and energizes the electromagnetic solenoid 29a of the reduction valve 29 accordingly. With this energization, the reduction valve 29 shifts from the open state to the closed state. Thereby, the fuel pressure at the time of start-up of engine 10 can be raised quickly, and it contributes to improvement in startability. When the start of the engine 10 is completed, the energization to the electromagnetic solenoid 29a is released, and the reduction valve 29 is opened.

  In the present embodiment, the example in which the reduction valve 29 is opened and closed only at the start-up when the engine 10 is in a normal operation state has been described. However, the present invention is not limited to this. For example, the throttle fully open (WOT) state The reduction valve 29 may be closed even during a high load operation such as the above. In this case, by closing the reduction valve 29, the amount of fuel supplied to the engine 10 can be increased at an early stage, and the driver's high load operation request can be responded with good response.

  As described above, since the fuel pressure control device according to the present embodiment has the check valve 40 provided between the branch portion 42 and the delivery pipe 23, the normally open type electromagnetic valve is stopped when the engine 10 is stopped. The fuel pressure in the supply passage 22a can be maintained by the check valve 40 even when the energization of the weight reduction valve 29 configured as described above is released. For this reason, it is not necessary to maintain the energization to the reduction valve 29 in order to maintain the fuel pressure when the operation of the engine 10 is stopped. Electric power consumption can be suppressed, which can contribute to improvement in fuel consumption. As described above, the fuel pressure control apparatus according to the present embodiment employs a normally open solenoid valve as the reduction valve 29 for controlling the fuel consumption to be less than the minimum fuel discharge amount of the electric fuel pump 21. Even in this case, it is possible to maintain the fuel pressure when the engine 10 is stopped while suppressing the power consumption.

  In addition, the fuel pressure control apparatus according to the present embodiment can prevent the fuel pump 21 from being stopped due to a foreign object biting because the fuel pump 21 is driven with an applied voltage that is equal to or higher than the lower limit voltage Vmin. Further, the reduction valve 29 functions as a control valve for returning the fuel difference between the minimum fuel discharge amount of the fuel pump 21 and the required fuel consumption amount when the fuel pump 21 is driven at the lower limit voltage Vmin to the fuel tank 30. Therefore, the required fuel consumption can be made less than the minimum fuel discharge amount corresponding to the lower limit voltage Vmin while maintaining the applied voltage of the fuel pump 21 at the lower limit voltage Vmin or higher. Therefore, excessive fuel consumption can be suppressed, and fuel consumption can be improved.

  Furthermore, since the fuel pressure control device according to the present embodiment has the check valve 40 provided between the branch portion 41 and the branch portion 42, the fuel pressure in the supply passage 22a is reduced to the fuel pressure via the relief valve 28. It is possible to control the pressure below a predetermined pressure that is specified in order to prevent abnormal rise.

  In the present embodiment, the engine 10 is configured by an internal combustion engine that performs only port injection for injecting fuel into the intake port. However, the present invention is not limited to this, and a cylinder that directly injects fuel into the combustion chamber in the cylinder. You may comprise with the internal combustion engine of the dual injection system which uses together internal injection and port injection which injects a fuel in the intake port corresponding to a cylinder.

  As described above, the fuel pressure control device according to the present invention employs a normally open solenoid valve as a reduction valve for controlling the fuel consumption to be less than the minimum fuel discharge amount of the electric fuel pump. Even so, it is possible to hold the fuel pressure when the internal combustion engine is stopped while suppressing power consumption, and it is useful for a fuel pressure control device that controls the pressure of fuel supplied to the fuel injection valve of the internal combustion engine mounted on a vehicle or the like It is.

1 vehicle 10 engine (internal combustion engine)
13 port injector (fuel injection valve)
DESCRIPTION OF SYMBOLS 20 Fuel supply mechanism 21 Fuel pump 22 Fuel piping 22a Supply passage 23 Delivery pipe 26 Relief piping 26a Relief passage 27 Return piping 27a Return passage 28 Relief valve 29 Reduction valve 29a Electromagnetic solenoid 29b Valve body 29c Coil spring 30 Fuel tank 40 Reverse Stop valve 41, 42 Branch part 100 ECU

Claims (1)

An electric fuel pump that pumps fuel stored in a fuel tank to a delivery pipe to which a fuel injection valve of an internal combustion engine is connected via a supply passage;
A return passage that branches off from the supply passage and returns a part of the fuel flowing in the supply passage to the fuel tank;
A reduction valve that is provided in the return passage, is closed by energization, and is configured by a normally open solenoid valve that is opened when the energization is released,
A check valve for preventing a back flow of fuel from the delivery pipe side to the fuel tank side is provided between the return passage, the branch portion of the supply passage, and the delivery pipe .
The fuel pump is configured to be driven with an applied voltage equal to or higher than a lower limit voltage capable of maintaining driving even if foreign matter is caught in the sliding portion,
The reduction valve is a differential fuel between a fuel discharge amount of the fuel pump when the fuel pump is driven at the lower limit voltage and a required fuel consumption amount required for the internal combustion engine according to an operating state of the internal combustion engine. Having a function as a control valve for returning the fuel to the fuel tank,
A relief passage that is connected to the supply passage on the delivery pipe side than the return passage, and connects the supply passage and the fuel tank;
A relief valve provided in the relief passage and opened when the pressure of the fuel flowing in the supply passage reaches a predetermined pressure,
The fuel pressure control device , wherein the check valve is provided between the supply passage and the branch portion of the relief passage, and the return passage and the branch portion of the supply passage .

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