JP3811982B2 - Returnless fuel supply system for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention supplies fuel to an EFI (Electronic Fuel Injection) of an internal combustion engine or the like. Returnless fuel supply system for internal combustion engine It is about.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a system related to a fuel filter for an internal combustion engine and a fuel supply device, a system that controls a voltage of a fuel pump and has a return pipe is known. In such a system, the pressure of fuel in the fuel rail (delivery pipe) to which the fuel injection valve is fixed (hereinafter simply referred to as “fuel pressure”) is made constant by a pressure regulator, and excess fuel is passed through the return pipe. It is controlled to return to the fuel tank. For this reason, it is necessary to keep the fuel pressure in the fuel rail at the maximum pressure that can be used regardless of the operating state of the internal combustion engine, etc., so it is wasteful in terms of energy and requires return piping, which makes it difficult to reduce costs. It was.
[0003]
In contrast to the above-described system, there has been proposed a system that does not require a return pipe without using a sensor that detects a fuel pressure by controlling the current value of an electric motor that drives a fuel pump. In this case, the fuel pressure at the fuel pump outlet can be controlled with high accuracy.
[0004]
[Problems to be solved by the invention]
By the way, if foreign matter adheres to the high-pressure fuel filter installed on the downstream side of the fuel pump, fuel pressure loss (hereinafter simply referred to as “pressure loss”) increases. Then, the fuel pressure in the fuel rail disposed on the downstream side of the high-pressure side fuel filter decreases, and as a result, an internal combustion engine that requires a large amount of fuel injection from the fuel injection valve fixed to the fuel rail. When the engine is in the high output range, there is a problem that the fuel injection amount decreases and the air-fuel ratio shifts to the lean side.
[0005]
Accordingly, the present invention has been made to solve such a problem, and in a fuel supply system without a return pipe, there is adhesion of minute foreign matters to the fuel filter disposed in the middle of the fuel pipe, and the pressure loss caused thereby fluctuates. Can maintain the predetermined fuel pressure in the fuel injection valve Returnless fuel supply system for internal combustion engine Is a challenge.
[0006]
[Means for Solving the Problems]
Claim 1 Returnless fuel supply system for internal combustion engine Accordingly, the differential pressure control means is arranged, so that the differential pressure between the fuel pressure on the upstream side and the fuel pressure on the downstream side of the fuel filter that is set to a predetermined pressure by the discharge pressure control means and discharged from the fuel pump is constant. And the differential pressure is set to be larger than the fluctuation of the pressure loss of the fuel filter itself. This differential pressure control means is connected to a pressure chamber upstream of the valve portion, a fuel passage connected to the downstream side of the valve portion and the inlet side of the fuel filter, and to the outlet side of the fuel filter. Back Pressure and biasing force of coil spring From the back pressure chamber When the back pressure in the back pressure chamber drops below a predetermined pressure relative to the fuel pressure in the pressure chamber, the valve opens the fuel passage and introduces the pressure of the fuel discharged from the fuel pump to the inlet side of the fuel filter. In addition, when the back pressure of the back pressure chamber becomes equal to or higher than a predetermined pressure with respect to the fuel pressure in the pressure chamber, the valve portion closes the fuel passage so that the differential pressure is kept constant. In addition, the opening and closing of the valve unit is controlled by the pressure of the fuel on the downstream side, and the valve opening pressure is set larger than the fluctuation amount of the pressure loss of the fuel filter itself. Achieved with a pressure regulator Ru . For this reason, the fuel filter has a simple configuration in which a pressure regulator as a differential pressure control means is connected in parallel to the inlet side and the outlet side of the fuel filter, and the upstream side of the fuel filter regardless of the pressure loss fluctuation of the fuel filter itself. The differential pressure between the fuel pressure on the fuel side and the fuel pressure on the downstream side is guaranteed, and the fuel filter has deteriorated due to adhesion of foreign matter. Also, The fuel pressure on the fuel pump side upstream of the fuel filter Control the fuel pressure to be the sum of the fuel pressure in the desired fuel rail and the valve opening pressure of the preset pressure regulator. If it does, the effect that the fuel pressure with respect to the fuel injection valve side which is a downstream can be made into predetermined pressure will be acquired.
[0009]
Also , Fuel pump and fuel injection Fuel rail to which the valve is connected A fuel filter is disposed between the two. For this reason, by arranging the fuel filter having the differential pressure control means in the vicinity of the periphery of the fuel pump, for example, it is possible to construct an extremely practical fuel supply device that is easy to arrange in the fuel tank.
[0011]
Also The discharge pressure control means is achieved by a current control circuit that controls the current flowing through the electric motor built in the fuel pump to a predetermined value. That is, since the current flowing through the electric motor built in the fuel pump and the fuel pressure discharged from the fuel pump are in a proportional relationship, the fuel pressure can be easily set to a predetermined pressure by using the current control circuit. Is obtained.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
[0013]
FIG. 1 is a schematic diagram showing the overall configuration of a fuel filter for an internal combustion engine and a fuel supply device according to an embodiment of the present invention.
[0014]
In FIG. 1, a fuel pump 10 is disposed in the fuel tank 1, and a low-pressure fuel filter 13 is connected to the suction side of the fuel pump 10. A pressure regulator 40 is connected to the discharge side of the fuel pump 10 through a fuel passage 56. The pressure regulator 40 is divided into an inlet chamber 41a and a spring chamber 41b by a diaphragm 43. One spring chamber 41b is provided with a compression coil spring 47 applied with a biasing force, and the opening of the pipe 57 projecting into the other inlet chamber 41a is closed by the diaphragm 43 biased by the compression coil spring 47. It has been. A high-pressure fuel filter 20 is connected to a pipe 57 on the discharge side of the pressure regulator 40, and a fuel rail 5 is connected to the discharge side of the high-pressure fuel filter 20 via a fuel pipe 2. The fuel rail 5 is connected with fuel injection valves 6 corresponding to the number of cylinders for supplying fuel to each cylinder of an internal combustion engine (not shown). The discharge side of the high-pressure fuel filter 20 is connected to a spring chamber 41 b on the back pressure side of the pressure regulator 40 through a fuel passage pipe 58. The current supplied to the fuel pump 10 is controlled by a current control circuit 9 built in the fuel pump 10. In addition, the fuel injection valve 6 and the current control circuit 9 are controlled by an ECU (Electronic Control Unit) 8.
[0015]
The ECU 8 is a logic including a CPU 8a as a known central processing unit, a ROM 8b storing a control program, a RAM 8c storing various data, a B / U (backup) RAM 8d, an input / output circuit 8e, a bus line 8f connecting them, and the like. It is configured as an arithmetic circuit. Various sensors for detecting the operation state of the internal combustion engine (not shown) are connected to the ECU 8, and various sensor signals 70 from these sensors are input to the CPU 8a via the input / output circuit 8e of the ECU 8. The ECU 8 is connected to the fuel injection valve 6 and the current control circuit 9, and the control signals are output from the ECU 8 to them.
[0016]
In the above configuration, when the fuel is pumped up by the fuel pump 10 disposed in the fuel tank 1, large foreign matters contained in the fuel are removed by the low pressure side fuel filter 13, and the fuel pump 10 pumps up the fuel. The raised fuel is sent to the high-pressure fuel filter 20 via the fuel passage 56, the pressure regulator 40, and the pipe 57. In the high-pressure side fuel filter 20, minute foreign matters and moisture contained in the fuel are removed, and the filtered fuel is sent to the fuel rail 5 through the fuel pipe 2. The high-pressure fuel supplied to the fuel rail 5 is injected from the fuel injection valve 6 so as to face an intake port of an internal combustion engine (not shown).
[0017]
Since this configuration is a so-called returnless fuel supply system, there is no return pipe for returning the fuel from the fuel rail 5 or the like to the fuel tank 1. Therefore, in this embodiment, as will be described later, the current control circuit 9 does not show the fuel pump 10 in the fuel pump 10 so that the fuel pressure in the fuel rail 5 corresponding to the amount of fuel supplied from the fuel rail 5 becomes a predetermined pressure. The current to the electric motor (pump motor) is controlled.
[0018]
FIG. 2 is a cross-sectional view showing the main configuration of the internal combustion engine fuel filter and fuel supply device according to the present embodiment, and FIG. 3 is a view in the direction of arrow A in FIG.
[0019]
As shown in FIGS. 2 and 3, the fuel pump 10, the high-pressure fuel filter 20, the electrical connector 38, the pressure regulator 40, the fuel level gauge 50, and other functional parts are provided on the upper wall of the fuel tank 1. It is provided inside the fuel tank 1 through the opening.
[0020]
As shown in FIG. 3, the arrangement of the parts belonging to these fuel supply devices is as follows. As shown in FIG. 3, the fuel pump 10 is arranged at the central shaft portion of the cylindrical unit. A C-shaped high-pressure fuel filter 20 is provided in the range of the half circumference. Further, an electrical connector 38, a pressure regulator 40, a fuel level gauge 50, and a fuel passage 56 are disposed in a space on one side around the fuel pump 10 where the high-pressure side fuel filter 20 is not provided. The fuel level gauge 50 is installed below the pressure regulator 40 shown in FIG.
[0021]
As a result, various functional components can be arranged and configured in a cylindrical shape at a high density within the range allowed by the fuel tank depth using the space around the substantially solid cylindrical fuel pump 10. This improves the workability when the unit of the fuel supply device is attached to the fuel tank 1. Note that the low-pressure fuel filter 13 and the float of the fuel level gauge 50 extend from the cylindrical unit.
[0022]
Next, the arrangement configuration of the fuel pump 10, the high-pressure fuel filter 20, and the pressure regulator 40 will be described with reference to FIGS.
[0023]
As shown in FIG. 2, a fuel pump 10 is disposed inside a pump case 12 that is fitted to the lower part of a filter case 21, and a half-cylindrical high-pressure fuel filter that is a half cylinder upward from the middle of the fuel pump 10. 20 is arranged. As a result, when viewed from the side rather than in series in the pump axial direction of the fuel pump 10, the high-pressure side fuel filter is partially disposed around the fuel pump in a direction partially overlapping with the fuel pump 10 in the pump axial direction of the fuel pump 10. Since the lower end portion of 20 is arranged, the length in the pump axial direction, that is, the height in the depth direction of the fuel tank is reduced, and the outer shape of the fuel supply device having a compact highly integrated functional component is obtained.
[0024]
The pump case 12 that houses the pump body 11 of the fuel pump 10 has a claw 95 snap-fitted into the hole 96 of the filter case 21. Thus, the pump body 11 can be easily detached from the filter case 21 by removing the pump case 12 from the filter case 21. The pump body 11 is floated by an upper rubber member 122 and a lower rubber member 124, and is supported and fixed by the pump case 12 and the filter case 21.
[0025]
From the fuel in the fuel tank 1 pumped up by the pump body 11, first, large foreign matters and the like are removed by the low-pressure side fuel filter 13. The fuel sent from the pump body 11 to the pressure regulator 40 is adjusted to a predetermined pressure by the pressure regulator 40 and then sent to the high-pressure side fuel filter 20. Water is further removed and supplied from the fuel discharge pipe 24 to the fuel injection valve 6 side.
[0026]
The high-pressure fuel filter 20 is assembled to the fuel pump 10 and the pressure regulator 40 so as to be detachable from each other. The filter case 21 is formed in an annular shape from a resin material, and forms a container that accommodates the filter element 30 only in a partial angle range. The filter case 21 has a C-shaped cross section orthogonal to the axis of the fuel pump 10. The filter case 21 includes an upper case 22 and a lower case 31, and the upper case 22 and the lower case 31 are welded at a boundary portion 29. The lower case 31 forms a container having a C-shaped cross section, and the C-shaped opening has a wall along the outer periphery of the fuel pump 10, and a hole 96 is formed in the wall to support the fuel pump 10. Part of the part is configured. A fuel level gauge 50 is also supported on this wall.
[0027]
The upper case 22 of the filter case 21 is entirely made of an insulating resin, and the lower case 31 is conductive because it is formed by containing a conductive material such as carbon fiber or carbon powder in the resin material. In the present embodiment, the lower case 31 is electrically connected to the metal case of the pump body 11 and is not connected to the fuel tank 1 and the vehicle body on which the fuel tank 1 is mounted. The lower case 31 may be electrically connected to the vehicle and grounded.
[0028]
The high pressure side fuel filter 20 is attached to the fuel tank 1 by fitting the peripheral portion of the upper case 22 as a lid into the groove portion 1a formed in the peripheral portion of the upper wall opening of the fuel tank 1 via the gasket 121. Yes. A fuel intake pipe 33 provided in the filter case 21 of the high-pressure fuel filter 20 and forming a fuel inlet is connected to the discharge pipe 14 of the pump body 11. A fuel discharge pipe 24 provided in the filter case 21 of the high-pressure fuel filter 20 and forming a fuel outlet supplies the fuel from which minute foreign matters and the like have been removed by the filter element 30 to the fuel injection valve 6 side. Further, a passage hole (not shown) drilled in the passage 54 of the filter case 21 and the spring chamber 41 b of the pressure regulator 40 are connected by a fuel passage pipe 58.
[0029]
As shown in FIG. 3, the electrical connector 38 is disposed at a position above the upper case 22 so as not to overlap the semi-cylindrical high-pressure fuel filter 20 when viewed from above. The terminal of the electrical connector 38 is electrically connected to the electrical connector 15 of the fuel pump 10 via a lead wire, and supplies power to an electric motor (not shown) that drives the pump body 11.
[0030]
As shown in FIG. 2, the outer peripheral wall of the discharge pipe 14 provided on the upper part of the pump body 11 and the inner wall of the fuel suction pipe 33 of the high-pressure fuel filter 20 are sealed by a rubber member 122. Therefore, it is not necessary to fit the discharge pipe 14 and the fuel suction pipe 33 so tightly that the discharge pipe 14 and the fuel suction pipe 33 are easily processed, and the fuel pump 10 and the high-pressure fuel filter 20 Desorption is facilitated. A check valve 18 is accommodated in the discharge pipe 14. The check valve 18 prevents the fuel discharged from the discharge pipe 14 from flowing back to the pump main body 11 and maintains the fuel residual pressure in the fuel pipe when the pump main body 11 is stopped.
[0031]
The pressure regulator 40 is attached to a pressure regulator attachment portion 61 of a pipe 57 that is fitted to the fuel passage pipe 34 via an O-ring 123. The lower portion of the pipe 57 on the downstream side is connected to a filter inlet chamber hole 53 a formed in the lower case 31 of the filter case 21 via a passage member 59. The passage member 59 is a liquid-tight connection between the pipe 57 and the filter inlet chamber hole 53a using a plurality of O-rings arranged at predetermined positions. The passage member 59 is connected to the pipe 57 by a fixing member 59a. It is fixed.
[0032]
As a result, the pressure regulator 40 can be easily detached from the filter case 21 by removing the fixing member 59a from the pipe 57, removing the passage member 59, removing the pipe 57 from the fuel passage pipe 34, and removing the fuel passage pipe 58. it can. The end portion of the pressure regulator housing 41 is caulked and fixed to the pressure regulator mounting portion 61 such that the outer edge portion of the diaphragm 43 is sandwiched between the end portion of the pressure regulator housing 41 and the pressure regulator mounting portion 61. A communication hole 41c is formed in the pressure regulator housing 41, and the spring chamber 41b of the pressure regulator housing 41 is connected to a fuel passage pipe 58 in a passage hole (not shown) formed in the passage 54 of the filter case 21 through the communication hole 41c. Connected by. For this reason, the fuel pressure in the spring chamber 41b to which the back pressure is applied is set to be the fuel pressure in the discharge passage 24a of the fuel discharge pipe 24, that is, the fuel pressure in the fuel rail 5. The valve body 51 that is integrally fixed to the diaphragm 43 is urged toward the seat portion 45 side of the pipe 57 by the urging force of the compression coil spring 47.
[0033]
Next, the flow of fuel will be described.
[0034]
The fuel discharged from the low pressure side fuel filter 13 through the fuel pump suction port, through the inside of the pump and discharged from the discharge pipe 14 by the pumping up of the fuel pump 10 passes through the passage 56 in the upper case 22 and is shown in the direction of the arrow in FIG. Proceed to This fuel descends at the downstream end of the passage 56 and is introduced into the inlet chamber 41 a of the pressure regulator 40 from the inlet passage 57 a of the pipe 57. The fuel introduced into the inlet chamber 41a of the pressure regulator 40 is regulated by the pressure regulator 40 and proceeds to the filter inlet chamber 53 through the outlet passage 57b. This fuel enters the passage 54 through the filter element 30 and is supplied from the discharge passage 24a of the fuel discharge pipe 24 to the fuel injection valve 6 side. Here, the fuel pressure in the passage 54 is applied to the spring chamber 41 b of the pressure regulator 40 through the fuel passage pipe 58.
[0035]
Next, the operation of the fuel supply device will be described with reference to the characteristic diagrams showing the relationship between the fuel pressure and the amount of supplied fuel in FIGS.
[0036]
In FIG. 2, the diaphragm 43 of the pressure regulator 40 is moved to the spring chamber 41b side against the urging force of the compression coil spring 47 and the fuel pressure on the spring chamber 41b side when the fuel pressure in the inlet chamber 41a exceeds a predetermined pressure. At this time, since the valve body 51 is moved together with the diaphragm 43 and is separated from the seat portion 45, the fuel in the inlet passage 57a of the pipe 57 is introduced into the filter inlet chamber 53 of the high-pressure fuel filter 20 through the outlet passage 57b. Is done. After that, the fuel pressure of the fuel that has passed through the filter element 30 of the high-pressure fuel filter 20 decreases due to the filter pressure loss caused by passing through the filter element 30. Here, since the fuel pressure in the passage 54 on the downstream side of the high-pressure fuel filter 20 is fed back to the spring chamber 41b side of the pressure regulator 40, the fuel pressure drop due to the filter pressure loss is compensated, that is, the outlet passage 57b of the pipe 57. The fuel pressure inside is increased by the fuel pressure drop due to the filter pressure loss.
[0037]
In order to achieve an increase in fuel pressure commensurate with the decrease in fuel pressure due to this filter pressure loss, as shown in FIG. 4, the valve opening of the pressure regulator 40 with respect to the desired fuel pressure in the fuel rail 5 (for example, fuel rail pressure 170-250 kPa). The pressure is preset to a pressure (for example, a pressure regulator valve opening pressure of 20 to 50 kPa) that exceeds the filter pressure loss after deterioration of the filter element 30 in the high-pressure fuel filter 20. Then, the current supplied to the fuel pump 10 is controlled so that the fuel pressure at the outlet of the fuel pump 10 (fuel pump outlet pressure) is equal to the fuel pressure obtained by adding the fuel pressure in the fuel rail 5 and the valve opening pressure of the pressure regulator 40. .
[0038]
Note that the fuel pressure in the fuel rail 5 (fuel rail pressure) Valve opening pressure of pressure regulator 40 Is the pressure of the outlet passage 57b of the pipe 57 (pipe outlet passage pressure). Further, the fuel pressure in the fuel rail 5 at the time of high temperature start is raised to, for example, a fuel rail pressure of 300 to 500 kPa in order to suppress the generation of vapor (gas) in the fuel. Thereby, the fuel supplied from the high pressure side fuel filter 20 to the fuel injection valve 6 side via the pressure regulator 40 from the fuel pump 10 can be held at a predetermined fuel pressure.
[0039]
According to the present embodiment, the partial annular high-pressure fuel filter 20 is disposed concentrically with the pump shaft of the fuel pump 10 when viewed from the top of the fuel pump 10. Then, functional parts such as the electrical connector 38, the pressure regulator 40, and the fuel level gauge 50 are arranged using the remaining partial annular space where the high-pressure fuel filter 20 is not provided. For this reason, there is an effect that the physique length in the pump axial direction of the fuel supply device, that is, the physique length in the fuel tank depth direction can be shortened. In the above-described embodiment, in order to form the partial annular high-pressure fuel filter 20, the lower case 31 having a C-shaped cross section is fixed to the upper case 22, and the filter element 30 is accommodated therein. The pump body 11 is grounded on the inner peripheral side of the lower case 31, and other components such as the pressure regulator 40 are disposed in the open space of the C-shaped lower case 31.
[0040]
As described above, by disposing various functional parts in the direction of the pump axis of the fuel pump 10 and in the space around the pump axis to form a unit, a fuel supply device having a substantially cylindrical shape as a whole can be configured. Thereby, there exists an effect that size reduction and size reduction of fuel supply apparatus itself can be achieved.
[0041]
In the present embodiment, the high-pressure fuel filter 20 and the pressure regulator 40 are replaceable. Further, since the pressure regulator 40 is accommodated in the fuel tank 1 and only the one-way fuel pipe 2 from the fuel tank 1 to the internal combustion engine is provided, the fuel heated in the vicinity of the internal combustion engine can be used as surplus fuel. As a result, it is not returned to the fuel tank 1 again. For this reason, the rise in the fuel temperature in the fuel tank 1 is suppressed, and generation of fuel vapor or bubbles in the fuel can be suppressed.
[0042]
In this embodiment, the high-pressure fuel filter 20, the pipe 57, and the pressure regulator 40 are disposed on the outer periphery of the fuel pump 10 so as to overlap in the circumferential direction. Similarly, the high-pressure fuel filter 20 and the fuel level gauge 50 are disposed on the outer periphery of the fuel pump 10 so as to overlap in the circumferential direction. Similarly, the high-pressure fuel filter 20 and the electrical connector 38 are disposed on the outer periphery of the fuel pump 10 so as to overlap in the circumferential direction.
[0043]
As described above, the fuel filter for an internal combustion engine according to the present embodiment removes minute foreign matters and moisture in the fuel supplied to the internal combustion engine. The fuel filter on the upstream side of the high-pressure side fuel filter 20 and the downstream side A differential pressure control means for maintaining a constant differential pressure with respect to the fuel pressure is provided.
[0044]
Accordingly, the differential pressure between the upstream side fuel pressure and the downstream side fuel pressure of the high pressure side fuel filter 20 is kept constant by the differential pressure control means. For this reason, in the high-pressure side fuel filter 20 provided with the differential pressure control means regardless of the pressure loss fluctuation of the high-pressure side fuel filter 20 itself, the differential pressure between the upstream side fuel pressure and the downstream side fuel pressure is guaranteed.
[0045]
Further, the differential pressure control means in the fuel filter for the internal combustion engine of the present embodiment sets the differential pressure to be larger than the fluctuation amount of the pressure loss of the high pressure side fuel filter 20 itself.
[0046]
Therefore, even if the high-pressure fuel filter 20 is deteriorated due to adhesion of foreign matters, the downstream fuel pressure is guaranteed.
[0047]
And the differential pressure control means in the fuel filter for an internal combustion engine of the present embodiment includes an inlet chamber 41a as a pressure chamber on the upstream side of the valve portion including the diaphragm 43 into which fuel flows, the valve body 51, and the seat portion 45; A pipe 57 serving as a fuel passage connecting the downstream side of the valve portion and the inlet side of the high-pressure side fuel filter 20 and the outlet side of the high-pressure side fuel filter 20 are connected to apply a back pressure on the pressure chamber to the valve portion. The pressure regulator 40 includes a spring chamber 41b as a back pressure chamber.
[0048]
Therefore, the differential pressure is kept constant by a simple configuration in which the pressure regulator 40 as the differential pressure control means is connected to the high-pressure fuel filter 20 and the back pressure is fed back.
[0049]
Further, the fuel supply device for the internal combustion engine of the present embodiment includes a high pressure pressure regulator 40 as a differential pressure control means between the fuel pump 10 for pumping fuel and the fuel injection valve 6 for supplying fuel to the internal combustion engine. A side fuel filter 20 is provided.
[0050]
Therefore, by disposing the high-pressure fuel filter 20 having the pressure regulator 40 in the vicinity of the periphery of the fuel pump 10, for example, an extremely practical fuel supply device that can be easily disposed in the fuel tank 1 can be constructed.
[0051]
In addition, the fuel supply device for the internal combustion engine of the present embodiment includes a discharge pressure control means that is achieved by a current control circuit 9 that sets a fuel pressure discharged from the fuel pump 10 to a predetermined pressure.
[0052]
Therefore, the fuel pressure on the fuel pump 10 side is a predetermined pressure in the current control circuit 9 as the discharge pressure control means using the high pressure side fuel filter 20 having the pressure regulator 40 as the differential pressure control means and maintaining the differential pressure constant. When set to, the fuel pressure for the fuel injection valve 6 side can be set to a predetermined pressure.
[0053]
Furthermore, in the fuel supply device for an internal combustion engine of this embodiment, the fuel pump 10 is driven by a built-in electric motor, and the discharge pressure control means includes a current control circuit 9 that controls the current flowing through the electric motor to a predetermined value. To do.
[0054]
That is, since the current flowing through the electric motor built in the fuel pump 10 and the fuel pressure discharged from the fuel pump 10 are in a proportional relationship, the fuel pressure can be easily set to a predetermined pressure by using the current control circuit 9. it can.
[0055]
In the above embodiment, the differential pressure control means is the pressure regulator 40. However, the present invention is not limited to this, and the upstream side fuel pressure of the high-pressure fuel filter 20 is not limited to this. What is necessary is just to be able to keep the pressure difference with the downstream fuel pressure constant.
[0056]
Further, in the above embodiment, the high-pressure side fuel filter 20 provided with the pressure regulator 40 is arranged in the vicinity of the periphery of the fuel pump 10 and accommodated in the fuel tank 1, but when the present invention is implemented, However, the arrangement of the pressure regulator 40 and the high pressure side fuel filter 20 can be appropriately set.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the overall configuration of a fuel filter and a fuel supply device for an internal combustion engine according to an example of an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a main configuration of a fuel filter and a fuel supply device for an internal combustion engine according to an example of an embodiment of the present invention.
FIG. 3 is a view taken in the direction of the arrow A in FIG.
FIG. 4 is a characteristic diagram showing the relationship between the fuel pressure and the amount of supplied fuel in the internal combustion engine fuel filter and fuel supply device according to an example of the embodiment of the present invention;
[Explanation of symbols]
6 Fuel injection valve
8 ECU (electronic control unit)
9 Current control circuit (Discharge pressure control means)
10 Fuel pump
20 High-pressure side fuel filter
40 Pressure regulator (Differential pressure control means)

Claims (1)

A fuel pump driven by an electric motor to pump up fuel in a fuel tank and a fuel rail connected to a fuel injection valve for supplying fuel to each cylinder of the internal combustion engine are disposed between the fuel pump and the fuel pump. A fuel filter that removes minute foreign matter and moisture in the discharged fuel ;
A discharge pressure control means for setting a predetermined pressure the pressure of the fuel discharged from said fuel pump,
While maintaining the differential pressure between the pressure of the fuel upstream of the fuel filter and the pressure of the fuel downstream of the fuel filter set by the discharge pressure control means, the differential pressure varies with the pressure loss of the fuel filter itself. Differential pressure control means for setting larger than the minute,
The differential pressure control means is a pressure regulator, and includes a pressure chamber on the upstream side of a valve portion into which fuel is introduced, a fuel passage connecting a downstream side of the valve portion and an inlet side of the fuel filter, A back pressure chamber connected to the outlet side of the fuel filter and applying a back pressure against the pressure chamber and a biasing force of a coil spring to the valve portion, and the back pressure in the back pressure chamber against the fuel pressure in the pressure chamber When the pressure drops below a predetermined pressure, the valve portion opens the fuel passage, introduces the pressure of the fuel discharged from the fuel pump to the inlet side of the fuel filter, and the back pressure in the back pressure chamber is the pressure. When the pressure exceeds a predetermined pressure relative to the fuel pressure in the chamber, the valve portion closes the fuel passage, and the pressure of the fuel on the upstream and downstream sides of the fuel filter is maintained so that the differential pressure is kept constant. Control the opening and closing of the valve Both the opening pressure of the pressure regulator is set larger than the variation in the pressure loss of the fuel filter itself,
The discharge pressure control means has a current control circuit for controlling a current supplied to the electric motor to a predetermined value, and the pressure of the fuel discharged from the fuel pump is preset with a desired fuel pressure in the fuel rail. A returnless fuel supply device for an internal combustion engine , wherein the current is controlled so that a fuel pressure is obtained by adding a valve opening pressure of the pressure regulator .

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