JP4045382B2 - Fuel supply device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel supply device that supplies high-pressure fuel to a fuel injection device of an internal combustion engine.
[0002]
[Prior art]
Conventionally, a solenoid valve has been provided on the fuel suction side of the fuel pressurization chamber, and when the solenoid valve is opened, the plunger is lowered so that fuel is sucked into the fuel pressurization chamber and the plunger is raised when the solenoid valve is closed. As a fuel supply device that pressurizes the fuel by doing so, a device disclosed in JP-A-8-14140 is known. In the high-pressure fuel pump as such a fuel supply device, as shown in FIG. 6, the fuel inlet 110, the delivery valve 111, and the pressure regulator 112 are directed toward the axial center of the plunger 102 with respect to the housing 101 of the high-pressure fuel pump 100. Generally, they are screwed radially.
[0003]
[Problems to be solved by the invention]
However, in the configuration in which each mounting component is radially coupled to the housing 101 toward the axial center of the plunger 102, an axial force due to the screw coupling acts on the seating surface of the housing 101 to which each mounting component is locked. A force is applied to the cylinder 103. Then, as shown in FIG. 7, the inner peripheral surface of the cylinder 103 having a circular cross section indicated by a two-dot chain line 120 before the screw connection is deformed into a shape indicated by a solid line 121 after the screw connection. That is, the clearance between the plunger 102 and the cylinder 103 that is uniform and h in the circumferential direction before the screw connection is (h−σ) where the clearance after the screw connection is reduced.
[0004]
When the clearance is reduced in part as described above, fuel as a lubricant is not sufficiently supplied to the portion where the clearance is reduced. As a result, the sliding portion between the plunger 102 and the cylinder 103 is burned, and the plunger 102 cannot move back and forth. There is a fear.
In addition, the mounting parts are mounted radially on the housing 101, and the position of the seating surface of the housing 101 that locks the mounting parts to prevent the deformation of the cylinder 103 cannot be brought too close to the cylinder 103. There is a problem that the amount of the housing interposed therebetween increases, and the housing cannot be reduced in size. Furthermore, since it is necessary to form fuel passages connected to the respective attachment parts, there is a problem that the number of processing steps of the fuel passages cannot be reduced.
[0005]
An object of the present invention is to provide a fuel supply device that prevents deformation of a cylinder portion due to attachment of attachment parts, prevents seizure of a plunger, and can be miniaturized.
Another object of the present invention is to provide a fuel supply device that reduces the number of processing steps.
[0006]
[Means for Solving the Problems]
According to the fuel supply device of the first to sixth aspects of the present invention, the virtual extension region obtained by extending the seating surface of the housing in which all the mounting components are locked in the mounting direction is the inner periphery of the cylinder portion that slides with the plunger. It is located outside the surface. Therefore, when the mounting part is attached to the housing, the shaft force by which the mounting part presses the seating surface hardly adds to the inner peripheral surface of the cylinder portion that slides with the plunger. As a result, the inner peripheral surface of the cylinder portion is not deformed, so that the sliding clearance between the plunger and the cylinder portion can be kept substantially constant, and seizure between the plunger and the cylinder portion can be prevented.
[0007]
Furthermore, if the virtual extension region of the seating surface is located outside the inner peripheral surface of the cylinder part, the mounting parts can be brought as close as possible to the inner peripheral surface of the cylinder part, thereby reducing the size of the housing and reducing the weight of the device. can do.
According to the fuel supply device of the fourth aspect of the present invention, the sliding clearance between the plunger and the cylinder portion can be kept substantially constant even when the mounting part is attached to the housing by the screw connection to which a large axial force is applied. Accordingly, seizure between the plunger and the cylinder portion can be prevented, and the attachment component can be firmly and easily attached to the housing.
[0008]
According to the fuel supply device of the fifth aspect of the present invention, the housing and the cylinder portion are separate members, and the virtual extension region of the seat surface is located outside the outer peripheral surface of the cylinder portion. Therefore, even if a mounting part is attached to the housing, almost no force is applied to the cylinder portion from the outer peripheral side, so that deformation of the inner peripheral surface of the cylinder portion can be prevented more reliably.
[0009]
According to the fuel supply apparatus of the first aspect of the present invention, at least one set of attachment parts connected to the fuel passage having the same fuel pressure is attached to face the same cross section of the housing. Thereby, the fuel path connected to the mounting part which opposes can be comprised by one. Therefore, the number of processing steps for the fuel passage is reduced.
According to the fuel supply device of the second or third aspect of the present invention, the attachment component is attached to the housing in parallel with the perpendicular line that is lowered from the restriction position where the fuel supply device is attached to the engine toward the central axis of the plunger. The mounting part can be attached to the housing as close as possible to the position. Therefore, it is possible to prevent the cylinder part from being deformed when the attachment part is attached. Furthermore, since there are at least two fuel pipes connected to the attachment parts, the fuel pipes can be easily routed and connected. Furthermore, the amount of the housing that fills the space between the mounting parts is reduced by collecting the mounting parts in the housing and mounting them in parallel. Accordingly, the size of the housing can be reduced and the apparatus can be miniaturized.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of examples showing embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1 to 4 show a high-pressure fuel pump as a fuel supply apparatus according to a first embodiment of the present invention. The high-pressure fuel pump 1 sucks low-pressure fuel pumped from a fuel tank (not shown) by a low-pressure fuel pump (not shown), and supplies the high-pressure fuel pressurized by the high-pressure fuel pump 1 to a distribution pipe (not shown). As many fuel injectors as the number of cylinders are attached to the distribution pipe. The housing 11 of the high-pressure fuel pump 1 is bolted to the engine at two restraining positions 11a shown in FIG.
[0011]
As shown in FIG. 2, a cylinder 12 as a cylinder portion is fixed in the housing 11 of the high-pressure fuel pump 1. The cylinder 12 supports the plunger 13 so as to be reciprocally movable, and slides with the plunger 13 on an inner peripheral surface 12a as a sliding surface. The head 13 a of the plunger 13 is fixed to a bottomed cylindrical tappet 14, and the plunger 13 reciprocates together with the tappet 14. The tappet 14 is urged downward in FIG. 2 by a spring 15, and the plunger 13 and the tappet 14 are reciprocated by a cam 100 shown in FIG. The outer wall of the plunger 13 is sealed by a rubber seal member 16 outside the cylinder 12.
[0012]
A fuel pressurizing chamber 17 is formed at the end of the plunger 13 by the inner wall of the cylinder 12. The low pressure fuel sucked into the fuel pressurizing chamber 17 by the lowering of the plunger 13 is pressurized by the raising of the plunger 13.
The solenoid valve 20 is attached above the housing 11 by a retaining nut 27. The valve member 21 is supported by the valve body 22 so as to be reciprocally movable, and is urged in a valve opening direction by a spring (not shown). A plurality of communication holes 22 a are formed in the valve body 22 in the radial direction, and the communication holes 22 a communicate with an accommodation hole for accommodating the valve member 21 and an annular fuel chamber 25 formed outside the valve body 22. Yes. The movement of the valve member 21 in the valve opening direction is restricted by the seat plate 24. A communication hole 24 a that penetrates the sheet plate 24 is formed in the sheet plate 24.
[0013]
A control current is supplied from an engine control device (ECU) (not shown) to a solenoid portion (not shown) of the solenoid valve 20 via a connector 26, and the solenoid valve 20 is opened and closed by turning this control current on and off. When the solenoid valve 20 with the energization to the solenoid portion opened is opened, the annular fuel chamber 25 is connected to the fuel pressurizing chamber 17 via the communication hole 22a, the opening between the valve member 21 and the valve seat 23, and the communication hole 24a. Communicate. When energization of a solenoid unit (not shown) is turned on, the valve member 21 is attracted against the urging force of the spring and is seated on the valve seat 23. Thereby, the communication between the annular fuel chamber 25 and the fuel pressurizing chamber 17 is blocked.
[0014]
As shown in FIGS. 1, 3, and 4, the fuel inlet 40, the delivery valve 41, and the pressure regulator 42 as mounting parts are screwed to the housing 11 on the same cross section orthogonal to the axis of the high-pressure fuel pump 1. ing. Further, as shown in FIG. 1, the fuel inlet 40, the delivery valve 41 and the pressure regulator 42 are screwed to the housing 11 in parallel with a perpendicular line dropped from one of the two restraining positions 11 a to the axial center of the plunger 13. Yes. Further, virtual extension regions 40 a, 41 a, 42 a obtained by extending the seating surface of the housing 11 to which each mounting component is locked in the mounting direction are located outside the outer peripheral surface 12 b of the cylinder 12. In the case of the fuel inlet 40, the seating surface is the outer peripheral wall of the housing 11 that contacts the fuel inlet 40. In the case of the delivery valve 41 and the pressure regulator 42, the seating surface is the bottom of a screw hole provided in the housing 11.
[0015]
The fuel inlet 40 and the pressure regulator 42 are connected to one fuel intake passage 30 that is a low-pressure fuel passage so as to face each other. The fuel intake passage 30 communicates with the annular fuel chamber 25 through a fuel intake passage 31. The pressure regulator 42 opens when the pressure of the fuel introduced from the fuel intake passage 30 into the annular fuel chamber 25 exceeds a predetermined pressure and returns surplus fuel to a fuel tank (not shown), and the fuel pressure in the annular fuel chamber 25 is predetermined. Prevent pressure over pressure.
[0016]
The fuel discharge passage 32 connects the fuel pressurization chamber 17 and the delivery valve 41, and opens when the fuel pressure in the fuel pressurization chamber 17 exceeds a predetermined pressure, and pumps high-pressure fuel to a distribution pipe (not shown).
Next, the operation of the high pressure fuel pump 1 will be described.
(1) While the energization of the intake stroke solenoid is off, the valve member 21 is separated from the valve seat 23 and the solenoid valve 20 is opened. When the plunger 13 descends toward the bottom dead center in this state, the volume of the fuel pressurizing chamber 17 increases, so that the communication hole 22a from the annular fuel chamber 25, the opening between the valve member 21 and the valve seat 23, and the communication hole 24a. After that, the low pressure fuel is sucked into the fuel pressurizing chamber 17.
[0017]
(2) Energization of the solenoid unit when the plunger 13 reaches a position corresponding to a desired fuel discharge amount in a stroke that rises toward the top dead center after the pressure / pressure feed stroke plunger 13 reaches the bottom dead center. Turn on. When the valve member 21 is seated on the valve seat 23 against the biasing force of the spring by the magnetic force generated by energization of the solenoid portion, the communication between the annular fuel chamber 25 and the fuel pressurizing chamber 17 is established. Is cut off. When the plunger 13 is further raised, the fuel in the fuel pressurizing chamber 17 is pressurized. When the fuel pressure in the fuel pressurizing chamber 17 becomes equal to or higher than a predetermined pressure, the delivery valve 41 is opened, high pressure fuel is discharged from the fuel discharge passage 32, and is pumped to the distribution pipe. The high-pressure fuel pumped to the distribution pipe is injected from the injector at a predetermined timing.
[0018]
In the first embodiment, the virtual extension regions 40 a, 41 a, 42 a that extend in the mounting direction the seating surface of the housing 11 to which the fuel inlet 40, the delivery valve 41, and the pressure regulator 42 as mounting parts are locked are provided in the cylinder 12. It is located outside the outer peripheral surface 12b. Therefore, even when each mounting component is screwed to the housing 11, even if the mounting component presses against the seat surface, the axial force is hardly applied to the cylinder 12. Thereby, since it can prevent that the internal peripheral surface 12a of the cylinder 12 deform | transforms and a sliding clearance becomes small, it can prevent that the cylinder 12 and the plunger 13 burn. Furthermore, the sliding clearance is increased, and high pressure fuel can be prevented from leaking from the fuel pressurizing chamber 17 through the sliding portion between the cylinder 12 and the plunger 13.
[0019]
In addition, since the mounting part is screwed to the housing 11 in parallel with the perpendicular line dropped from one of the two restraining positions 11a to the axial center of the plunger 13, the amount of the housing 11 filling between the mounting parts is reduced. However, the housing 11 is reduced in size and weight.
Furthermore, since the fuel inlet 40 and the pressure regulator 42 are connected to one fuel intake passage 30 that is a low-pressure fuel passage so as to face each other, it is not necessary to form a fuel passage for each fuel inlet 40 and the pressure regulator 42. The man-hour for processing the fuel passage is reduced.
[0020]
(Second embodiment)
A second embodiment of the present invention is shown in FIG. Components that are substantially the same as those in the first embodiment are denoted by the same reference numerals.
In the second embodiment, the fuel inlet 40 and the pressure regulator 42 are not connected to the common fuel intake passage, but are connected to the annular fuel chamber 25 by the fuel intake passages 33 and 34, respectively.
[0021]
In the above-described plurality of examples showing the embodiment of the present invention described above, a virtual surface in which the seating surface of the housing 11 to which the fuel inlet 40, the delivery valve 41, and the pressure regulator 42 as the mounting parts are locked is extended in the mounting direction. The extension regions 40a, 41a, 42a are located outside the outer peripheral surface 12b of the cylinder 12. Therefore, the axial force by which the attachment component pushes the seat surface when screwed to the housing 11 is not applied to the inner peripheral surface 12 a of the cylinder 12 that slides with the plunger 13. Thereby, since the inner peripheral surface 12a of the cylinder 12 is not deformed, the sliding clearance between the plunger 13 and the cylinder 12 can be kept substantially constant, and seizure between the plunger 13 and the cylinder 12 can be prevented.
[0022]
In addition, the attachment component can be brought as close to the axial center of the plunger 13 as long as the axial force of the attachment component screwed to the housing 11 acts at least outside the outer peripheral surface 12 b of the cylinder 12. Further, since the attachment parts are attached to the housing 11 in parallel with the perpendicular line that is lowered toward the central axis of the plunger 13 from one of the two restraining positions 11a where the high-pressure fuel pump is attached to the engine, the attachment parts are arranged in parallel. It can be integrated and screwed to the housing 11. Therefore, the amount of the housing that fills the space between the mounting parts is reduced, and the size of the housing 11 can be reduced.
[0023]
Furthermore, since there are at least two fuel pipes connected to the attachment parts, the fuel pipes can be easily routed and connected, and can be easily mounted on the engine.
Furthermore, since the attachment part can be attached to the housing 11 as close as possible to the restraint position 11a, the housing itself is not easily deformed even if the attachment part is screwed to the housing 11.
[0024]
In the above-described plurality of embodiments, the mounting part is configured to be screw-coupled to the housing 11. The mounting method is not limited to screw coupling, and the mounting part may be attached to the housing using a fixing member such as a clamp. .
In the above embodiments, the virtual extension regions 40a, 41a, 42a are positioned outside the outer peripheral surface 12b of the cylinder 12, but the virtual extension region is at least outside the inner peripheral surface 12a of the cylinder 12. Is located, the deformation of the inner peripheral surface 12a when attaching the mounting part to the housing 11 can be reduced.
[0025]
In the above embodiments, two restraint positions 11a are provided, but three or more restraint positions 11a may be provided. Even in this case, the housing 11 can be reduced in size by collecting and attaching the mounting parts to the housing 11 in parallel with the perpendicular dropped from any one of the restraining positions 11a toward the central axis of the plunger 13. .
[0026]
In the above embodiments, the housing 11 and the cylinder 12 are configured as separate members, but the housing and the cylinder may be configured integrally. In this case, when the mounting part is screwed to the housing, the virtual extension region extending the seating surface of the housing in the mounting direction is positioned outside the inner peripheral surface of the cylinder portion that slides with the plunger. The seizure between the cylinder part and the plunger can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a high-pressure fuel pump according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing a high-pressure fuel pump according to the first embodiment.
FIG. 3 is a plan view showing a high-pressure fuel pump according to the first embodiment.
4 is a view in the direction of arrows IV in FIG. 3;
FIG. 5 is a cross-sectional view showing a high-pressure fuel pump according to a second embodiment of the present invention.
FIG. 6 is a cross-sectional view showing a conventional high-pressure fuel pump.
FIG. 7 is a schematic view showing a deformation of a cylinder when a mounting part screw is coupled according to a conventional example.
[Explanation of symbols]
1 High-pressure fuel pump (fuel supply device)
12 cylinder (cylinder part)
12a Inner peripheral surface 12b Outer peripheral surface 13 Plunger 17 Fuel pressurizing chamber 20 Solenoid valve 40 Fuel inlet (mounting parts)
40a Virtual extension area 41 Delivery valve (mounting parts)
41a Virtual extension area 42 Pressure regulator (Mounting parts)
42a Virtual extension area

Claims (6)

A fuel supply device for supplying high pressure fuel to a fuel injection device of an internal combustion engine,
A housing;
A plunger that is reciprocally supported by a cylinder portion in the housing and pressurizes the fuel sucked into the fuel pressurizing chamber;
A plurality of attachment parts attached to the side of the cylinder portion of the housing;
A virtual extension region that extends the seating surface of the housing that locks all the mounting parts in the mounting direction is located outside the inner peripheral surface of the cylinder portion that slides with the plunger ,
The fuel supply device according to claim mounting Rukoto at least one pair of the fitting is disposed in the fuel passage to face on the same cross-section of the housing with the same fuel pressure. 2. The fuel supply device according to claim 1, wherein the attachment component is attached to the housing in parallel with a perpendicular line that is lowered from a restraining position where the fuel supply device is attached to the internal combustion engine toward the central axis of the plunger. A fuel supply device for supplying high pressure fuel to a fuel injection device of an internal combustion engine,
  A housing;
  A plunger that is reciprocally supported by a cylinder portion in the housing and pressurizes the fuel sucked into the fuel pressurizing chamber;
  A plurality of attachment parts attached to the side of the cylinder portion of the housing;
  A virtual extension region that extends the seating surface of the housing that locks all the mounting parts in the mounting direction is located outside the inner peripheral surface of the cylinder portion that slides with the plunger,
  The fuel supply device, wherein the attachment component is attached to the housing in parallel with a perpendicular line that is lowered from a restraining position where the fuel supply device is attached to an internal combustion engine toward a central axis of the plunger. The fuel supply device according to any one of claims 1 to 3, wherein the attachment component is screwed to the housing. The fuel according to any one of claims 1 to 4, wherein the housing and the cylinder part are separate members, and the virtual extension region is located outside the outer peripheral surface of the cylinder part. Feeding device. 6. The mounting part according to claim 1, wherein the other mounting part is attached to the housing in parallel or opposite to one of the mounting parts. Fuel supply system.

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