JP2010121485A - Fuel supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device controlling fuel pressure to a prescribed value without using a pressure detection means measuring fuel pressure by driving and controlling a fuel pump to deliver demand fuel delivery quantity adding relief flow rate providing the prescribed fuel pressure to engine demand fuel quantity corresponding to operation conditions of an engine. <P>SOLUTION: In the fuel supply device, a pressure regulating device 6 is composed to provide fuel pressure in high pressure piping 3b corresponding to the relief flow rate, and a control unit 7 is composed to calculate the relief flow rate providing the prescribed fuel pressure, to calculate demand fuel delivery quantity by adding the calculated relief flow rate to the engine demand fuel quantity calculated based on the engine operation conditions, and to control motor rotation speed of the fuel pump 4 to deliver the calculated demand fuel delivery quantity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine fuel supply device, and more particularly to a technique capable of easily controlling a fuel pressure.

  The conventional fuel supply device is provided with pressure detection means for detecting the pressure of the fuel pumped from the fuel pump to the fuel injection valve, and the required discharge amount of the fuel pump is determined based on the comparison between the target fuel pressure value and the actual fuel pressure. The fuel pump is driven and controlled based on the determined required discharge amount (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 06-147047

  The conventional fuel supply apparatus requires pressure detecting means for measuring the fuel pressure as a control parameter, which increases the number of component parts, making it impossible to reduce the cost and complicating the piping layout.

  The present invention has been made to solve such a problem, and discharges a required fuel discharge amount obtained by adding a relief flow rate at which a predetermined fuel pressure is obtained to an engine required fuel amount corresponding to an engine operating condition. Thus, an object of the present invention is to obtain a fuel supply device capable of controlling the fuel pressure to a predetermined value without using pressure detection means for controlling the fuel pump and measuring the fuel pressure.

  The fuel supply device according to the present invention includes a fuel tank in which fuel is stored, a fuel injection valve that injects the fuel, and sucks fuel from the fuel tank, and pumps the fuel to the fuel injection valve through a high-pressure pipe. A fuel pump for operating the engine, an operating condition detecting means for detecting engine operating conditions, a pressure adjusting device for adjusting the fuel pressure in the high pressure pipe by relieving the fuel pumped through the high pressure pipe, and driving control of the fuel pump And a fuel pump control means. The pressure adjusting device is configured to obtain a fuel pressure in the high-pressure pipe corresponding to the relief flow rate, and the fuel pump control means calculates and calculates the relief flow rate at which a predetermined fuel pressure is obtained. The required fuel discharge amount is calculated by adding the relief flow rate to the engine required fuel amount calculated based on the engine operating condition detected by the operating condition detecting means, and the calculated required fuel discharge amount is discharged. Thus, the motor rotational speed of the fuel pump is controlled.

  According to the present invention, the fuel of the required fuel discharge amount obtained by adding the relief flow rate to the required fuel amount of the engine is discharged from the fuel pump to the high pressure pipe. Then, the fuel having the relief flow rate added to the engine required fuel amount is relieved by the pressure adjusting device, and the fuel pressure in the high-pressure pipe is adjusted to a predetermined fuel pressure corresponding to the relief flow rate. Therefore, the fuel of the engine required fuel amount adjusted to a predetermined fuel pressure is injected from the fuel injection valve. This eliminates the need for pressure detecting means for measuring the fuel pressure, reduces the number of components, reduces costs, and simplifies the piping layout.

  1 is a diagram showing a system configuration of a fuel supply apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view showing a configuration of a fuel pump in the fuel supply apparatus according to an embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view of the main part showing the configuration of the pressure regulator in the fuel supply apparatus according to one embodiment of the present invention, and FIG. 4 is a diagram for explaining the operation of the pressure regulator in the fuel supply apparatus according to one embodiment of the present invention. It is.

  In FIG. 1, a fuel supply apparatus sucks fuel in a fuel tank 1, a fuel injection valve 2 for injecting fuel into an intake pipe (not shown) of an engine, and a fuel in the fuel tank 1 through a low-pressure pipe 3a. A fuel pump 4 that pumps fuel to the fuel injection valve 2 through the high-pressure pipe 3 b and a return pipe 5 that branches from the high-pressure pipe 3 b are disposed in the fuel tank 1 with a part of the fuel pumped from the fuel pump 4. The pressure adjustment device 6 that adjusts the fuel pressure in the high-pressure pipe 3b, the intake air flow rate detection signal from the air flow meter 8, the rotational speed signal from the crank angle sensor 9, and the like are input, and the opening and closing timing of the fuel injection valve 2 and And a control unit 7 as fuel pump control means for controlling the rotational speed of the electric motor unit 31 of the fuel pump 4. The air flow meter 8 and the crank angle sensor 9 correspond to engine operating condition detection means.

Next, the configuration of the fuel pump 4 will be described with reference to FIG.
The fuel pump 4 includes a resin body 10 formed in a bottomed cylindrical shape, a disk-shaped casing 14 disposed on the bottom side of the body 10, and a cylinder disposed on the body opening side of the casing 14. 20, a cylindrical bush 29 disposed on the body opening side of the cylinder 20, and an electric motor that is fastened and fixed so as to close the opening of the body 10 and drives a piston 26 mounted on the cylinder 20. Part 31.

  The body 10 is molded using, for example, a resin such as nylon, and is formed at the bottomed cylindrical housing portion 11, the suction port 12 formed on the opening side of the housing portion 11, and the bottom portion of the housing portion 11. And a discharge port 13.

  The casing 14 is manufactured in an outer peripheral disk shape that conforms to the inner peripheral surface of the housing portion 11 using, for example, an iron-based material, and, for example, four through holes 15 are formed at an equiangular pitch on the same circumference. Yes. A valve seat is formed on the bottom side of the body 10 of each through hole 15. Further, the spring housing hole 16 is recessed in the bottom surface of the body 10 so as to face each through hole 15. A ball 17 is disposed so as to be able to contact and separate from the valve seat, and a spring 18 accommodated in the spring accommodating hole 16 is contracted between the ball 17 and the bottom surface of the spring accommodating hole 16 to press the ball 17 against the valve seat. Energized in the direction. Further, a fuel passage 19 is recessed in the bottom surface of the body 10 so as to communicate the through hole 15 and the discharge port 13.

  The cylinder 20 is produced in a cylindrical shape with an outer peripheral shape that fits the inner peripheral surface of the accommodating portion 11 using, for example, an iron-based material. The piston sliding hole 21 is formed in the cylinder 20 so as to face each of the through holes 15. Further, the communication hole 22 is formed in the cylinder 20 corresponding to each of the piston sliding holes 21. Each communication hole 22 is configured by coaxially connecting a large-diameter hole on the casing 14 side and a small-diameter hole on the body opening side, and a valve seat is formed at a connecting portion between the large-diameter hole and the small-diameter hole. The ball 23 is disposed in the large-diameter hole so as to be able to contact with and separate from the valve seat, and the spring 24 disposed in the large-diameter hole is contracted between the ball 23 and the casing 14 so that the ball 23 serves as the valve seat. It is energized in the pressing direction. Further, a fuel passage 25 is recessed in the surface of the casing 14 on the cylinder 20 side so as to communicate the corresponding piston sliding hole 21 and communication hole 22.

A piston 26 is mounted in each piston sliding hole 21 so as to be slidable in the axial direction. A spring 27 is contracted between the ring 28 attached to the piston 26 and the surface of the cylinder 20 on the body opening side, and is fitted to the piston 26 to urge the piston 26 toward the body opening side.
The bush 29 is made of, for example, an iron-based material and has an outer peripheral cylindrical shape that fits the inner peripheral surface of the accommodating portion 11. The bush 29 is formed in the bush 29 so that the communication port 30 communicates with the suction port 12 and the inside of the bush 29. Has been.

  The electric motor unit 31 is rotatably supported by a resin exterior material 32 such as nylon, a motor body 36 provided in the exterior material 32, and a bearing 42 in the exterior material 32, and this motor body. And a shaft 41 rotated by 36. The exterior material 32 has the fitting convex portion 33 fitted in the opening of the body 10 and is fastened and fixed by a screw (not shown) to close the opening of the housing portion 11 of the body 10. At this time, the O-ring 34 is mounted in the groove 35 formed in the outer peripheral surface of the fitting convex portion 33 over the entire circumference in the circumferential direction, and leakage of fuel passing between the body 10 and the exterior member 32 is prevented. It is preventing.

  The motor body 36 includes a stator 37 that is integrally molded with the exterior member 32, and a rotor 40 that is fixed to the shaft 41. The stator 37 includes an iron core 38 and a coil 39 formed by winding a conductive wire around the iron core 38. The rotor 40 includes a shaft 41 and a cylindrical permanent magnet 42 that is externally fixed to the shaft 41. The swash plate 43 is fixed to the extension end of the shaft 41 on the discharge port side, and the piston 26 is in contact with the surface of the swash plate 43 on the discharge port side by the urging force of the spring 27.

  The fuel pump 4 configured as described above is an axial piston pump in which the hole direction of the piston sliding hole 21, that is, the reciprocating direction of the piston 26 coincides with the axial direction of the shaft 41. In the fuel pump 4, a suction port 12 is connected to the fuel tank 1 via a low pressure pipe 3a, and a discharge port 13 is connected to the fuel injection valve 2 via a high pressure pipe 3b. And if electric power is supplied to the coil 39 of the electric motor part 31, the rotor 39 will be rotationally driven. Then, the swash plate 43 is rotated in conjunction with the rotation of the shaft 41. Due to the rotation of the swash plate 43 and the biasing force of the spring 27, the piston 26 reciprocates in the piston sliding hole 21 in the hole direction.

  In the suction process in which the piston 26 moves to the electric motor unit 31 side, the volume of the working chamber defined by the piston sliding hole 21 and the piston 26 is increased, and the working chamber is at a low pressure. Therefore, the ball 17 contacts the valve seat, and the through hole 15 is closed. On the other hand, the ball 23 moves toward the casing 14 against the urging force of the spring 24, and the fuel in the accommodating portion 11 flows into the working chamber through the communication hole 22 and the fuel passage 25.

  Next, in the discharge process in which the piston 26 moves to the casing 14 side, the volume of the working chamber becomes small, and the working chamber becomes high pressure. Therefore, the ball 23 comes into contact with the valve seat, and the communication hole 22 is closed. On the other hand, the ball 17 moves against the biasing force of the spring 18 to the bottom side of the spring housing hole 16, and the fuel in the working chamber is discharged to the discharge port 13 through the through hole 15 and the fuel passage 19. The fuel discharged to the discharge port 13 is supplied to the fuel injection valve 2 through the high-pressure pipe 3b.

  Here, the fuel pump 4 is constituted by a piston pump, and the fuel discharge amount is proportional to the motor rotation speed. The control unit 7 controls the motor rotation speed of the fuel pump 4 by changing the ratio of the power supply voltage to the rated voltage and controlling the magnitude of the power supply voltage, that is, duty-controlling the power supply voltage.

Next, the configuration of the pressure adjusting device 6 will be described with reference to FIG.
The pressure adjusting device 6 is a poppet valve type adjusting device, in which a ball valve 45 as a valve body is disposed so as to be able to contact and separate from a seat surface 46a of the valve seat 46, and a spring 47 connects the ball valve 45 to the valve seat 46. The pressure is applied so as to contact the sheet surface 46a. And the sheet | seat surface 46a comprises a truncated cone shape, and the vertex angle becomes a sheet | seat angle.

  The pressure adjusting device 6 configured as described above is disposed in the path of the return pipe 5 branched from the high-pressure pipe 3b. When the fuel pressure (fuel pressure) in the high-pressure pipe 3 b becomes higher than the urging force of the spring 47 acting on the ball valve 45, the ball valve 45 moves away from the seat surface 46 a against the urging force of the spring 47. Therefore, the fuel in the high-pressure pipe 3b is relieved from the space between the ball valve 45 and the seat surface 46a to the low-pressure side, as indicated by an arrow in FIG. The relief fuel is returned to the fuel tank 1 via the return pipe 5. Further, when the pressure of the fuel in the high pressure pipe 3b becomes lower than the urging force of the spring 47 acting on the ball valve 45, the ball valve 45 comes into contact with the seat surface 46a by the urging force of the spring 47, and the flow of fuel is stopped. . Thereby, the fuel pressure in the high-pressure pipe 3b is adjusted.

  Since the pressure adjusting device 6 is a poppet valve type, there is a fluid force exerted on the ball valve 45 by the fuel flowing along the seat surface 46a. This fluid force depends on the flow rate of the fuel to be relieved, the seat angle of the seat surface 46a, and the taper length. That is, the fluid force increases as the relief flow rate increases. Further, as the seat angle of the seat surface 46a becomes acute, the component of the fluid force in the valve closing direction increases. From this, the fluid force becomes the same force in the valve closing direction as the urging force of the spring 47, and exhibits a characteristic that the pressure increases as the relief flow rate increases. Further, when the taper length is fixed to a predetermined length and the seat angle is changed, the ratio of the pressure change with respect to the change in the relief flow rate, that is, the pressure gradient changes with the seat angle. That is, as shown by the dotted line in FIG. 4, when the seat angle is made obtuse, that is, increased, the pressure gradient is small. On the other hand, as shown by the solid line in FIG. 4, when the seat angle is sharpened, that is, reduced, the pressure gradient has a large characteristic.

Therefore, if the shape of the seat surface 46a is set so that the pressure gradient becomes a predetermined value, a predetermined value of fuel pressure can be obtained by adjusting the relief flow rate to a predetermined value. Thus, the pressure adjusting device 6 is configured to be able to adjust the fuel pressure in the high-pressure pipe 3b to a fuel pressure commensurate with the relief flow rate.
Even if the seat angle is fixed to a predetermined angle and the taper length of the seat surface 46a is changed, the pressure gradient can be changed.

  Next, a first fuel pressure control method by the control unit 7 will be described with reference to FIG. Here, although not shown, the control unit 7 performs an operation for controlling the fuel injection valve 2 and the fuel pump 4, an input interface that receives data sent from the air flow meter 8, the crank angle sensor 9, and the like. CPU to perform, memory for storing a program for controlling the fuel injection valve 2 and the fuel pump 4 and various data, and an output interface for sending a control signal for controlling the fuel injection valve 2 and the fuel pump 4 Etc. The various data stored in the memory include, for example, a map storing engine required fuel amount required for the engine corresponding to the engine operating conditions, a relief flow rate necessary for obtaining a predetermined fuel pressure, a fuel pump 4 is a map storing the relationship between the duty ratio for driving the fuel pump 4 calculated from the flow rate characteristics of 4 and the fuel discharge amount. In FIG. 5, steps 1 to 4 are S1 to S4.

First, in step 1, the control unit 7 controls the engine in accordance with the engine operating conditions based on the intake air flow rate detection signal input from the air flow meter 8 and the engine rotational speed signal input from the crank angle sensor 9. Referring to the map storing the required engine fuel amount required for the engine, the required engine fuel amount corresponding to the current operating condition is obtained. Here, the intake air flow rate detection signal and the engine speed signal are used as engine operating conditions. Further, the engine required fuel amount becomes the fuel injection amount injected from the fuel injection valve 2.
In step 2, the relief flow rate stored in the memory is read out, and the read relief flow rate is added to the engine required fuel amount to obtain the required fuel discharge amount required for the fuel pump 4.

In step 3, the duty ratio for driving the fuel pump 4 corresponding to the calculated required fuel discharge amount is determined by referring to a map storing the duty ratio for driving the fuel pump 4 corresponding to the fuel discharge amount of the fuel pump 4. obtain.
In step 4, the calculated duty ratio is output to the fuel pump 4.

  Therefore, the fuel pump 4 is driven at the calculated duty ratio. At this time, the rotational speed of the motor body 36 is controlled to a rotational speed commensurate with the duty ratio. Then, a discharge amount of fuel corresponding to the rotational speed of the motor body 36, that is, fuel corresponding to the required fuel discharge amount is discharged to the high-pressure pipe 3b. Then, the fuel corresponding to the relief flow rate is returned from the high-pressure pipe 3 b to the fuel tank 1 through the return pipe 5 by the pressure adjusting device 6. Then, the fuel of the required engine fuel amount obtained by subtracting the relief flow rate from the required fuel discharge amount is supplied to the fuel injection valve 2. A fuel injection amount corresponding to the current operating condition is injected from the fuel injection valve 2.

Thereby, the fuel pressure supplied to the fuel injection valve 2 can always be kept constant regardless of the operating conditions of the engine. In addition, because the fuel pressure is controlled to be constant, the relief flow rate is constant, and the fuel discharge amount corresponding to the relief flow rate is set to a duty ratio that can discharge the fuel discharge amount corresponding to the fuel injection amount corresponding to the engine operating conditions. All that is required is to add a duty ratio that can be discharged.
Here, if a pressure regulating device configured pressure gradient shown in FIG. 4, by setting the relief flow rate and Q _r1, you can control the fuel pressure in the P1, by setting the relief flow rate and Q _r2, the fuel pressure It can be controlled to P2. Further, when the fuel pressure is controlled to be constant regardless of the engine operating conditions, it is desirable to make the seat angle an obtuse angle from FIG.

  Next, a second fuel pressure control method by the control unit 7 will be described with reference to FIG. Here, the memory of the control unit 7 further stores a map that stores the relationship between the relief flow rate and the fuel pressure in the pressure adjusting device 6. In FIG. 6, steps 10 to 15 are designated as S10 to S15.

First, in step 10, the control unit 7 controls the engine according to the engine operating conditions based on the intake air flow rate detection signal input from the air flow meter 8 and the engine rotational speed signal input from the crank angle sensor 9. Referring to the map storing the required engine fuel amount required for the engine, the required engine fuel amount corresponding to the current operating condition is obtained.
In step 11, a target fuel pressure at which the differential pressure with respect to the engine intake negative pressure is constant is calculated.
In step 12, a map storing the relationship between the relief flow rate and the fuel pressure in the pressure adjusting device 6 is referred to obtain a relief flow rate at which the calculated target fuel pressure is obtained.

In step 13, the calculated relief flow rate is added to the engine required fuel amount to obtain the required fuel discharge amount required for the fuel pump 4.
In step 14, the duty ratio for driving the fuel pump 4 corresponding to the calculated required fuel discharge amount is determined by referring to a map storing the duty ratio for driving the fuel pump 4 corresponding to the fuel discharge amount of the fuel pump 4. obtain.
In step 15, the calculated duty ratio is output to the fuel pump 4.

  Therefore, the fuel pump 4 is driven at the calculated duty ratio, and fuel corresponding to the required fuel discharge amount is discharged to the high-pressure pipe 3b. Then, the fuel corresponding to the calculated relief flow rate is returned from the high pressure pipe 3 b to the fuel tank 1 via the return pipe 5 by the pressure adjusting device 6. Then, the fuel of the required engine fuel amount obtained by subtracting the relief flow rate from the required fuel discharge amount is supplied to the fuel injection valve 2. A fuel injection amount corresponding to the current operating condition is injected from the fuel injection valve 2.

As a result, the fuel pressure supplied to the fuel injection valve 2 can always be maintained at a fuel pressure at which the differential pressure from the engine suction negative pressure is constant, regardless of the engine operating conditions. Therefore, the fuel injection amount can be accurately controlled by the valve opening time of the fuel injection valve 2.
Here, if the pressure adjusting device configured with the pressure gradient shown in FIG. 4 is used, if the target fuel pressure is P1, the relief flow rate is _Qr1 , and if the target fuel pressure is P2, the relief flow rate is _Qr2 . Become. Thus, variable fuel pressure control can be realized with a simple configuration. Further, when the fuel pressure is variably controlled regardless of the engine operating conditions, it is desirable to make the seat angle an acute angle from FIG.

  Thus, according to the present invention, the pressure adjusting device 6 is configured to obtain the fuel pressure in the high-pressure pipe 3b corresponding to the relief flow rate, and the relief flow rate from the pressure adjusting device 6 matches the operating conditions of the engine. Since the required fuel discharge amount calculated by adding to the engine required fuel amount is discharged by controlling the rotational speed of the motor body 36 of the fuel pump 4, pressure detection for measuring the fuel pressure in the high-pressure pipe 3b. Means are not required, the number of components is reduced, the configuration is simplified, and the size is reduced. Therefore, an inexpensive fuel supply device that can make the piping layout compact can be realized.

Further, since the fuel discharge amount is adjusted by controlling the rotation speed of the motor body 36 of the fuel pump 4, it is not necessary to increase the rotation speed of the motor body 36 more than necessary, and the power consumption of the motor body 36 is reduced. can do. Further, the amount of heat generated in the motor main body 36 can be reduced, heat transmitted to the fuel can be suppressed, and an increase in fuel temperature can be suppressed.
Furthermore, it is possible to cope with engines having different displacements, that is, engines having different fuel consumption and system fuel pressure by setting the rotation speed of the motor body 36 for each target system. Thus, since this invention can respond to a wide range of fuel consumption and fuel pressure, the fuel pump 4 and the pressure regulator 6 can be shared.

In addition, since the poppet valve type pressure adjusting device 6 is used, the number of components can be reduced and the configuration is simplified and the size can be reduced as compared with the diaphragm pressure adjusting device. Further, since the pressure gradient in the pressure adjusting device 6 can be adjusted by changing the seat angle and the taper length of the seat surface 46a, the pressure adjusting device 6 having a desired pressure gradient can be easily produced.
The temperature of the fuel that is relieved from the pressure adjusting device 6 is increased by receiving heat from the engine, but the amount of fuel that is relieved is controlled to the minimum amount necessary to maintain the fuel pressure, so the fuel tank The temperature rise of 1 can be suppressed.

  Further, the motor body 36 of the electric motor unit 31 of the fuel pump 4 includes a rotor 40 configured by fixing a permanent magnet 42 to a shaft 41, a stator 37 configured by winding a coil 39 around an iron core 38, Therefore, there is no power supply brush for energizing the coil. Therefore, it is not affected by the sliding resistance of the power supply brush, the responsiveness of the rotational speed is improved, the wear of the sliding portion is not deteriorated, and high reliability is obtained in the long term.

The motor body 36 includes a stator 37 formed by winding a coil 39 around an iron core 38, a rotor 40 formed by fixing a permanent magnet 42 to a shaft 41, and a diagonal fixed to the tip of the shaft 41. The motor main body 36 can be configured with low inertia.
Further, since the fuel pump 4 is a piston pump, the fuel discharge amount is proportional to the rotational speed of the motor body 36, and stable volumetric efficiency is obtained in a wide rotational speed range from low speed to high speed.

In the above embodiment, the fuel pump uses an axial piston pump in which the reciprocating direction of the piston is the axial direction of the shaft. However, the fuel pump is a direction orthogonal to the axial direction of the shaft. A radial piston pump may be used.
In the above embodiment, the return pipe branched from the high pressure pipe is connected to the fuel tank, and the relief fuel is returned to the fuel tank, but the return pipe branched from the high pressure pipe is connected to the low pressure pipe, The relieved fuel may be returned to the housing part of the fuel pump.
In the above embodiment, the intake air flow rate detection signal and the engine speed signal are detected as the engine operating conditions related to the required fuel amount of the engine. However, the throttle opening and the like are detected. May be.

It is a figure which shows the system configuration | structure of the fuel supply apparatus which concerns on one embodiment of this invention. It is sectional drawing which shows the structure of the fuel pump in the fuel supply apparatus which concerns on one embodiment of this invention. It is principal part sectional drawing which shows the structure of the pressure regulator in the fuel supply apparatus which concerns on one embodiment of this invention. It is a figure explaining operation | movement of the pressure regulator in the fuel supply apparatus which concerns on one embodiment of this invention. It is a figure explaining the 1st fuel pressure control method in the fuel supply apparatus concerning one embodiment of this invention. It is a figure explaining the 2nd fuel pressure control method in the fuel supply apparatus concerning one embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fuel tank, 2 Fuel injection valve, 3b High pressure piping, 4 Fuel pump, 6 Pressure regulator, 7 Control unit (fuel pump control means), 8 Air flow meter (Operating condition detection means), 9 Crank angle sensor (Operating condition detection) Means), 36 Motor body.

Claims (7)

A fuel tank in which fuel is stored;
A fuel injection valve for injecting the fuel;
A fuel pump that sucks fuel from the fuel tank and pumps the fuel to the fuel injection valve via a high-pressure pipe;
An operating condition detecting means for detecting an engine operating condition;
A pressure adjusting device that relieves the fuel pressure-fed through the high-pressure pipe and adjusts the fuel pressure in the high-pressure pipe;
Fuel pump control means for driving and controlling the fuel pump,
The pressure adjusting device is configured to obtain a fuel pressure in the high-pressure pipe corresponding to a relief flow rate,
The fuel pump control means calculates the relief flow rate at which a predetermined fuel pressure is obtained, and calculates the calculated relief flow rate based on the engine operating condition detected by the operating condition detection means. The fuel supply device is configured to calculate a required fuel discharge amount by adding to the above and to control the motor rotational speed of the fuel pump so as to discharge the calculated required fuel discharge amount.   2. The fuel supply device according to claim 1, wherein the fuel pump control means drives and controls the fuel pump so that the predetermined fuel pressure is constant regardless of the engine operating condition.   2. The fuel pump control means according to claim 1, wherein the fuel pump control means controls the fuel pump so that a differential pressure with respect to an engine intake load is constant regardless of the engine operating condition. Fuel supply device.   The fuel supply device according to any one of claims 1 to 3, wherein the pressure adjusting device is a poppet valve type.   The fuel supply apparatus according to any one of claims 1 to 4, wherein the fuel pump is a piston pump.   6. The fuel supply device according to claim 1, wherein the motor body of the fuel pump is a brushless motor.   The fuel supply apparatus according to any one of claims 1 to 6, wherein the fuel pump control means controls the motor rotation speed of the fuel pump by duty-controlling a power supply voltage.

Images