JP3826662B2 - Solenoid valve of fuel pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic valve of a fuel pump that is mounted on an internal combustion engine such as an automobile engine and supplies fuel to a fuel injection valve or the like.
[0002]
[Prior art]
Conventionally, as this type of fuel pump, one having an electromagnetic valve for opening and closing a fuel supply passage to a pressurizing chamber is known as shown in Japanese Utility Model Laid-Open No. 60-47874. This solenoid valve is provided with a valve portion composed of a valve body and a seat body, and is normally moved to a closed position where the valve body comes into contact with the seat portion of the seat body by a biasing force of a spring, The fuel supply is cut off. Further, when the coil is energized, the valve body is moved to a valve opening position that is separated from the seat portion of the seat body, and fuel is supplied from the fuel supply passage into the pressurizing chamber.
[0003]
[Problems to be solved by the invention]
However, in the conventional configuration, fuel is supplied into the pressurizing chamber by opening the valve body. Therefore, in order to take a predetermined amount of fuel into the pressurized chamber, it is necessary to set a large amount of movement of the valve body from the valve closing position to the valve opening position to increase the fuel flow rate in the valve opening state. There was a problem that the whole solenoid valve became large.
[0004]
The present invention has been made in order to solve such problems, and the object thereof is to set the amount of movement of the valve body from the valve closing position to the valve opening position within the pressurizing chamber. It is an object of the present invention to provide a solenoid valve for a fuel pump that can take in a required amount of fuel and reduce the overall shape.
[0005]
Another object of the present invention is to provide a solenoid valve for a fuel pump that can be easily processed without requiring high-precision sealing between the valve body and the seat portion of the seat body. is there.
[0006]
[Means for Solving the Problems]
In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 is a solenoid valve of a fuel pump that includes a valve portion that opens and closes a fuel supply passage to the pressurizing chamber of the fuel pump, and that adjusts the fuel supply amount to the pressurizing chamber. Separately, a gap is provided in a part of the contact surface between the valve body of the valve portion and the seat portion as a flow path for allowing the fuel to flow into the pressurizing chamber.
[0007]
Therefore, according to the first aspect of the present invention, fuel is supplied into the pressurizing chamber via the flow path even while the valve portion is closed. For this reason, a predetermined amount of fuel can be taken into the pressurizing chamber without taking a large amount of movement from the valve closing position to the valve opening position when the valve body is opened, and the overall shape can be reduced in size. Can do. In addition, since it is not necessary to completely close the valve portion, it is not necessary to ensure a highly accurate sealing property between the valve body and the seat portion of the seat body, and processing can be easily performed. Furthermore, since the flow path is formed by a gap provided in a part of the contact surface between the valve body and the seat part of the valve part, the flow path can be easily formed in a part of the contact surface between the valve body and the seat part. Can be processed and formed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS.
[0011]
As shown in FIG. 1, the high-pressure fuel pump 11 of this embodiment includes a pump unit 12 and an electromagnetic valve 13 attached to the top of the pump unit 12.
[0012]
The pump unit 12 includes a pump housing 14, a cylinder 15, a pressurizing chamber 16, and a plunger 17. The cylinder 15 is disposed at the center of the pump housing 14, and a pressurizing chamber 16 is provided on the upper end side thereof. The plunger 17 is inserted into and supported by the cylinder 15 so as to be slidable in the axial direction, and is reciprocated by the rotation of a cam mounted on a cam shaft (not shown).
[0013]
The electromagnetic valve 13 is disposed to face the pressurizing chamber 16 and includes a coil 18, a bobbin 19, a core 20, an armature 21, a poppet valve 22, a sheet body 23, and a cylindrical member 24. Yes. The coil 18 is wound around the outer periphery of the bobbin 19 in a ring shape. The bobbin 19 is fitted and fixed to the outer periphery of the cylindrical member 24, and the core 20 is fitted and fixed to the inner upper end of the cylindrical member 24. The armature 21 is slidably inserted and supported in the center of the cylindrical member 24 coaxially with the core 20 while being fixed to the upper end of the poppet valve 22. A spring 25 is disposed in a compressed state between the opposed end surfaces of the core 20 and the armature 21, and the armature 21 is urged toward the pressurizing chamber 16 by the spring 25.
[0014]
The sheet body 23 is fitted and fixed to the inner lower end of the cylindrical member 24, and a through hole 26 is formed in the upper portion of the sheet body 23 so as to extend in the axial direction. A fuel supply passage 27 including a plurality of first ports 27 a extending substantially in the radial direction and a second port 27 b extending coaxially with the through-hole 26 and extending in the axial direction is formed in the lower portion of the sheet body 23. Is formed with a seat portion 28 constituting a valve portion.
[0015]
The poppet valve 22 is slidably penetrated into the through hole 26 of the sheet body 23, and a valve body 29 constituting a valve portion is formed at an end thereof. When the coil 18 is not energized, the valve body 29 comes into contact with the seat portion 28 of the seat body 23 by the urging force of the spring 25, and the valve portion composed of the valve body 29 and the seat portion 28 is closed. ing. On the other hand, when the coil 18 is energized from an electronic control device (not shown), a magnetic circuit is formed by the core 20 and the armature 21 and the armature 21 moves toward the core 20 against the biasing force of the spring 25. Is done. As a result, the poppet valve 22 is moved to the opposite side of the pressurizing chamber 16, the valve body 29 is separated from the seat portion 28, and the valve portion is opened.
[0016]
A low pressure fuel passage 30 is formed in the pump housing 14 and the cylinder so as to communicate with the first port 27a of the fuel supply passage 27, and is connected to a pressure regulator (not shown). When the plunger 17 is lowered while the valve portion of the solenoid valve 13 is open, the low pressure fuel pumped from the fuel tank by the operation of a feed pump (not shown) is supplied to the pressure regulator, the low pressure fuel passage 30 and the fuel supply. The air is sucked into the pressurizing chamber 16 through the passage 27.
[0017]
A high pressure fuel passage 31 is formed in the cylinder 15 and the pump housing 14 so as to communicate with the pressurizing chamber 16, and a check valve (not shown) is provided in the high pressure fuel passage 31. When the pressure of the fuel pumped from the pressurizing chamber 16 through the high pressure fuel passage 31 exceeds a predetermined value, the check valve is opened. As a result, high-pressure fuel pumped from the high-pressure fuel passage 31 is supplied to a fuel distribution pipe (not shown) and distributed to each fuel injection valve attached to the cylinder head of the engine.
[0018]
In the high-pressure fuel pump 11 configured as described above, when the engine is driven, the cam is rotated along with the rotation of a camshaft (not shown), and the plunger 17 is connected to the cylinder 15 according to the profile of the cam surface. It is reciprocated in the axial direction. And the volume of the pressurization chamber 16 will be in the maximum state in the state which the plunger 17 was moved to the bottom dead center shown by the continuous line in FIG. From this state, when the plunger 17 is raised with the rotation of the cam, the volume of the pressurizing chamber 16 is compressed. When the plunger 17 reaches the top dead center indicated by a chain line in the drawing, the volume of the pressurizing chamber 16 is most compressed. The stroke from the bottom dead center to the top dead center of the plunger 17 is the pressure stroke.
[0019]
In this pressurization stroke, the valve portion of the electromagnetic valve 13 is closed, and the fuel supply passage 27 communicating with the pressurization chamber 16 is closed. For this reason, the fuel pressure in the pressurizing chamber 16 rises to become high-pressure fuel. The high-pressure fuel in the pressurizing chamber 16 is pumped from the high-pressure fuel passage 31 to the check valve side, pushes the check valve open, and is supplied to a fuel distribution pipe (not shown).
[0020]
Further, with the rotation of the cam, the plunger 17 is gradually lowered from the top dead center indicated by the chain line in FIG. 1, and again reaches the bottom dead center indicated by the solid line in FIG. The stroke from the top dead center to the bottom dead center of the plunger 17 is the suction stroke. The valve portion of the electromagnetic valve 13 is opened by energizing the coil 18 from the electronic control device at an appropriate timing of this suction stroke. As a result, fuel is sucked into the pressurizing chamber 16 from the low pressure fuel passage 30 side via the fuel supply passage 27.
[0021]
Thereafter, the pressurization stroke and the suction stroke described above are repeated, and a predetermined amount of high-pressure fuel is pumped from the high-pressure fuel passage 31 into the fuel distribution pipe.
Now, in the electromagnetic valve 13 of the high-pressure fuel pump 11 of this embodiment, as shown in FIGS. 1 to 3, the fuel to the pressurizing chamber 16 is provided separately from the valve portion composed of the valve body 29 and the seat portion 28. The flow path 32 for permitting the inflow of is provided. That is, a slit 33 is formed on the seat portion 28, and even when the valve element 29 is in contact with the seat portion 28, a gap as the flow path 32 is formed in a part between the contact surfaces. It has become.
[0022]
A check valve 34 is disposed in the second port 27 b of the fuel supply passage 27. The check valve 34 allows the flow of fuel from the first port 27a to the second port 27b side of the fuel supply passage 27. Further, the fuel in the pressurizing chamber 16 is restricted from flowing backward from the second port 27b to the first port 27a side through the flow path 32 when the valve portion is closed.
[0023]
Therefore, in the suction stroke of the high-pressure fuel pump 11, even when the valve body 29 of the electromagnetic valve 13 is in contact with the seat portion 28 and the valve portion is in the closed state, the pressure chamber 16 is brought into the pressure chamber 16 via the flow path 32. A predetermined amount of fuel is supplied. For this reason, when the valve body 29 is separated from the seat portion 28 and the valve portion is opened by energization of the coil 18, the inside of the pressurizing chamber 16 does not have to be set large. It will be possible to take in the required amount of fuel.
[0024]
In the pressurization stroke of the high-pressure fuel pump 11, since the check valve 34 is provided in the second port 27b of the fuel supply passage 27, the flow path from the pressurizing chamber 16 side with the valve portion closed is provided. The fuel does not flow back to the first port 27a side through 32. For this reason, there is no possibility that pressurization efficiency will be lowered by the outflow of fuel from the flow path 32.
[0025]
Now, this embodiment has the following effects.
(1) The electromagnetic valve 13 is equipped with a valve body 29 and a seat portion 28 for opening and closing a fuel supply passage 27 to the pressurizing chamber 16 of the fuel pump 11. In addition to the valve body 29 and the seat portion 28, a flow path 32 for allowing fuel to flow into the pressurizing chamber 16 is provided. Therefore, fuel is supplied into the pressurizing chamber 16 via the flow path 32 even while the valve body 29 and the seat portion 28 are closed. Therefore, a predetermined amount of fuel can be taken into the pressurizing chamber 16 without setting a large amount of movement from the valve closing position to the valve opening position when the valve element 29 is opened, and the electromagnetic valve 13 The overall shape, particularly in the axial direction, can be reduced in size. Further, since it is not necessary to completely close the valve portions 29 and 28, it is not necessary to ensure a highly accurate sealing property between the valve body 29 and the seat portion 28 of the seat body, and processing is easily performed. Manufacturing cost can be reduced.
[0026]
(2) In the electromagnetic valve 13, the flow path 32 is formed by a gap provided in a part of the contact surface between the valve body 29 of the valve portion and the seat portion 28. Therefore, the flow path 32 can be easily formed by processing the slit 33 or the like in a part of the contact surface between the valve body 29 and the seat portion 28.
[0027]
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, parts that are the same as or similar to those in the first embodiment are given the same reference numerals as those in the first embodiment to avoid redundant description, and detailed descriptions thereof are omitted.
[0028]
In the second embodiment, instead of the slit 33 of the first embodiment, the first port 27a and the second port 27b of the fuel supply passage 27 communicate with each other so as to bypass the seat portion 28. A small-diameter bypass hole 35 is formed. The bypass hole 35 communicates with the upstream side of the check valve 34 at the second port 27b. The bypass hole 35 constitutes a flow path 32 for allowing the fuel to flow into the pressurizing chamber 16.
[0029]
Therefore, also in this embodiment, it is possible to obtain substantially the same effect as the effect described in (1) in the first embodiment.
(Example of change)
In addition, embodiment is not limited above, You may change as follows. Even when configured in this manner, substantially the same effects as those of the above-described embodiment can be obtained.
[0030]
-In the said 1st Embodiment, you may form the slit 33 for comprising the flow path 32 in the contact surface by the side of the valve body 29. FIG.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing an electromagnetic valve of a fuel pump according to a first embodiment.
2 is an enlarged partial cross-sectional view of a part of the solenoid valve shown in FIG.
FIG. 3 is a partial plan view showing a sheet portion of a sheet body.
FIG. 4 is a partial cross-sectional view showing a solenoid valve of a fuel pump according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... High pressure fuel pump, 12 ... Pump part, 13 ... Solenoid valve, 15 ... Cylinder, 16 ... Pressurizing chamber, 17 ... Plunger, 18 ... Coil, 22 ... Poppet valve, 23 ... Seat body, 27 ... Fuel supply passage, 27a ... 1st port, 27b ... 2nd port, 28 ... Seat part which comprises valve part, 29 ... Valve body which comprises valve part, 30 ... Low pressure fuel passage, 31 ... High pressure fuel passage, 32 ... Flow path, 33 ... Slit, 34 ... Check valve, 35 ... Bypass hole.

Claims (1)

In a solenoid valve of the fuel pump that includes a valve portion that opens and closes a fuel supply passage to the pressurizing chamber of the fuel pump, and that adjusts the amount of fuel supplied to the pressurizing chamber.
Separately from the valve part, a fuel is provided with a gap in a part of a contact surface between the valve body and the seat part of the valve part as a flow path for allowing the fuel to flow into the pressurizing chamber. Pump solenoid valve.

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