JP3110021B2 - Fuel supply pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel supply pump for discharging fuel by reciprocating a plunger.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 9-112 discloses this type of apparatus.
The technology disclosed in Japanese Patent No. 731 is known. According to the technology disclosed in this publication, as shown in FIG. 6A, a fuel supply pump 100 is provided in a supply passage (low-pressure passage) 103 for supplying fuel to a pump chamber 101 and a supply passage 103. The fuel supplied to the pump chamber 101 is pressurized by the rise of the plunger 107 and is sent under pressure through the discharge valve 109.

[0003] The solenoid valve 105 includes a valve body 111 and a valve body 11.
And a spring 113 for urging the solenoid 1 away from the valve seat 112 (see arrow A). The action of the exciting coil 115 by energizing the solenoid valve 105 causes the valve body 111 to face the valve seat 112 (see FIG. (See arrow B.) The user moves and sits down, closing the supply passage 103. That is, the solenoid valve 105
It is a so-called externally-open valve, and is a type that closes when energized (valve closed when energized).

[0006] In the fuel supply pump 100 provided with such an electromagnetic valve 105, as shown in FIG. 6 (b), when the plunger 107 rises to a predetermined position during the upward stroke of the plunger 107, 105 is energized. With this energization, the valve body 111 is seated on the valve seat 112, thereby closing the supply passage 103 (closing the valve) and starting fuel pumping (controlling the start of fuel pumping). When the plunger 107 reaches the top dead center, the supply of electricity is stopped, so that the valve body 111 separates from the valve seat 112 to open the supply passage 103 and fuel flows into the pump chamber 101.

[0005]

However, in the above-mentioned prior art, when closing the supply passage 103, the valve seat 112 is closed.
Must be pulled back so as to be seated on the valve seat 112 (at the position where the air gap is at the maximum position). Therefore, it is necessary to increase the power supplied to the solenoid valve 105, and there is a problem that power consumption is large.

Accordingly, an object of the present invention is to provide a fuel supply pump that can reduce power consumption.

[0007]

According to a first aspect of the present invention, there is provided a suction valve, a discharge valve, a return passage for returning a part of fuel in a pump chamber to a low-pressure passage, and a return passage provided in the return passage and closed by energization. A fuel supply pump including an electromagnetic valve that generates an urging force in a valve direction, wherein the electromagnetic valve has a valve seat formed with a valve hole communicating with the pump chamber and a pressure in the pump chamber during a suction stroke.
And a valve body seated on the valve seat to move towards the more the pump chamber, when the valve body is in the closed state with the valve seat in the suction stroke, by performing the energization of the solenoid valve It is characterized by.

According to the first aspect of the present invention, when the pressure in the pump chamber is reduced during the fuel suction stroke, the valve body moves in the seating direction and seats on the valve seat, and the suction valve opens to open the fuel valve. Is sucked into the pump chamber. When the valve is seated on the valve seat and is in the closed state, by energizing the solenoid valve, an urging force is generated in the valve closing direction, so that the valve is provided with the valve closing force. . Then, the energized state is maintained in preparation for the next fuel discharge stroke.

Since power is supplied to the solenoid valve while the valve body is seated on the valve seat, the power supplied to the solenoid valve can be reduced, and the power consumption can be reduced. Also,
Since the electric power can be reduced, the booster circuit and the like can be omitted, and it is not necessary to increase the size of the excitation coil and the like of the solenoid valve, so that the solenoid valve can be downsized.

According to a second aspect of the present invention, in the first aspect of the present invention, the solenoid valve includes a spring for urging the valve body in a seating direction.

According to the second aspect of the present invention, the first aspect is provided.
In addition to the same effects as the invention described in (1), the moving direction of the valve body is guided by the spring, so that the valve body can be prevented from wobbling and the movement of the valve body can be stabilized.

[0012] The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described in the above, the communication with the solenoid valve is performed during the suction stroke.
The fuel discharge is controlled by starting power supply and stopping the power supply to the solenoid valve during the discharge stroke .

[0013] According to the third aspect of the present invention, the first aspect is provided.
Or when the fuel is discharged from the discharge valve and the energization of the solenoid valve is stopped, the valve element receives the fuel pressure of the pump chamber and the valve seat receives the fuel pressure. And the valve is opened. And
When the valve is opened, a part of the fuel in the pump chamber is returned to the return passage, and the discharge of the fuel ends. Discharging of the fuel can be easily terminated only by stopping the energization of the solenoid valve.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG.
An embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a sectional view showing a fuel supply pump according to the present invention, and FIG. 2 is a configuration diagram schematically showing the fuel supply pump. As shown in FIG. 1, the fuel supply pump 2 according to the present embodiment is a high-pressure pump that discharges (pressurizes) high-pressure fuel, and drives a pump housing 23 that houses a plunger 21 and the plunger 21. And a lower main body 27 in which the cam 25 is housed. The cam 25 is driven by an engine (not shown), and the cam 25 rotates by the driving of the engine. The cam 25 comes into circumferential contact with a cam contact shoe 29 provided at the lower end of the plunger 21 to reciprocate (vertically move) the plunger 21. Has become.

A first plunger 21 is provided at a lower end thereof.
The lower end of the spring 41 is in contact with the fixing member 37, and the upper end of the spring 41 is in contact with the second fixing member 39 provided below the barrel 50. The spring 41 constantly urges the plunger 21 downward. The upper end of the plunger 21 and the suction valve 17
A pump chamber 35 for pressurizing the fuel is formed between the two.

The pump housing 23 is provided with a suction port (not shown) for supplying low-pressure fuel, and a discharge port 31 for discharging fuel pressurized by raising the plunger 21.

The suction port communicates with the pressure receiving chamber 33 of the accumulator 19 provided in the pump housing 23. The pressure receiving chamber 33 of the accumulator 19 further communicates with the pump chamber 35 via the low pressure passage 45 and the suction valve 17. (See FIG. 2). The suction valve 17 is separated from the low-pressure passage 45 against the urging force of the spring 49 due to the pressure difference between the low-pressure passage 45 and the pump chamber 35 caused by the lowering of the plunger 21. Also, discharge port 3
1 is connected to a common rail (not shown) via a discharge valve 16 in the present embodiment.

On the other hand, the pump housing 23 is formed with a return passage 20 for returning a part of the fuel in the pump chamber 35 to the low-pressure passage 45 via the accumulator 19 when the fuel is being fed to the common rail by pressure. The return passage 20
Generally, it has a pump chamber-side communication passage 20a and an accumulator-side communication passage 20f, and these passages are connected to the solenoid valve 51.
Are communicated through.

The communication passage 20a on the pump chamber side is provided with a pump chamber 35.
And the high-pressure fuel from the pump chamber side communication passage 20a communicates with the accumulator 1
9 to the pressure receiving chamber 33.

The solenoid valve 51 opens and closes between the communication passage 20a on the pump chamber side and the communication passage 20f on the accumulator side.
As a result, the solenoid valve 51 opens and closes the return passage 20.
The solenoid valve 51 includes a needle valve (valve element) 53, a valve cylinder 55 that stores the needle valve 53, a valve seat 54 formed in a valve hole 52 that communicates with the pump chamber 35, and a needle valve via a shoe 57. A spring 59 for urging the valve 53 in a seating direction (toward the pump chamber 35). By providing the spring 59, the movement direction of the needle valve 59 can be guided, so that the needle valve 53 can be prevented from wobbling, and the movement of the needle valve 53 can be stabilized. In addition,
The fuel from the first intermediate passage 20b is
A guide path 57a for guiding to the intermediate passage 20c is formed.

As shown in FIG. 3, when the needle valve 53 is seated on the valve seat 54 and is closed, as shown in FIG. This is for applying a valve closing force to the needle valve 53. The solenoid valve 51 is a so-called internal valve, and generates a biasing force in the valve closing direction when energized (closed when energized).

Next, the operation of the present embodiment will be described based on the above-described configuration and FIG. 4A and 4B show the operation of the solenoid valve accompanying the plunger displacement. FIG. 4A is a graph in which the plunger displacement is plotted on the vertical axis and the time T is plotted on the horizontal axis, and FIG. The opening / closing operation is shown.

When the plunger 21 starts to descend after passing through the top dead center, the pressure in the pump chamber 35 is reduced, and the needle valve 53 is guided by the spring 59 to the seating direction (see the arrow C in FIG. 3). ) To sit on the valve seat 54.
At the same time, the suction valve 17 opens to draw fuel into the pump chamber 35. When the energization of the solenoid valve 51 is turned ON (when energization is performed) during this suction stroke, the needle valve 53 seated on the valve seat 54 has a valve closing force due to the urging force generated in the valve closing direction. Granted.

When the fuel is pressurized, the plunger 21 rises, and the fuel pressurized in the pump chamber 35 is discharged by opening the discharge valve 16. At this time, the solenoid valve 51 is in the closed state, and the energization to the solenoid valve 51 remains ON.

During the fuel discharge, when the plunger 21 rises to a predetermined position, the power to the solenoid valve 51 is turned off.
Set to F (stop energization). When the power is turned off,
The needle valve 53 receives the pressure from the pump chamber 35,
The valve hole 52 is opened apart from the valve seat 54. When the valve hole 52 is opened and the return passage 20 communicates with the pump chamber 35, the pump chamber 3
Part of the high-pressure fuel of No. 5 flows into the return passage 20 (spill), and the discharge of the fuel ends. Thus, the solenoid valve 51
It is possible to easily control the end of the fuel discharge simply by stopping the power supply to the fuel cell.

The fuel flowing into the return passage 20 is supplied to the pump chamber side communication passage 20a, the first intermediate passage 20b, the guide passage 57a,
A second intermediate passage 20c, a hole 20d, a third intermediate passage 20e,
The fluid passes through the accumulator-side communication passage 20f and returns to the low-pressure passage 45 via the pressure receiving chamber 33 of the accumulator 19. The fuel returned to the low-pressure passage 45 joins with the low-pressure fuel and is supplied to the pump chamber 35.

As shown in FIG. 3, in the case of the solenoid valve 51 which is closed when energized and is internally opened, as shown in FIG. 3, the closed state in which the needle valve 53 is seated on the valve seat 54 as shown in FIG. , Ie, energization is performed with the air gap S1 being the minimum. Therefore, the power supplied to the solenoid valve 51 can be reduced,
Power consumption can be reduced. Further, since the power can be reduced, the booster circuit and the like can be omitted, and the solenoid valve 51
Since it is not necessary to increase the size of the exciting coil 61 and the like, the electromagnetic valve 51 can be reduced in size, and the cost can be reduced.

On the other hand, even if the same internal valve is opened, FIG.
In the case of the solenoid valve 120 of the valve type which is open when energized as shown in FIG.
When the needle valve 53 seated on the valve seat 53 is energized, the valve seat 54
, And the power is supplied when the air gap S2 is at its maximum. In addition, since it is necessary to separate the needle valve 53 from the valve seat 54 against the urging force of the spring 121, a large amount of power is required for the power supplied to the solenoid valve 120, and a booster circuit is required. Or power consumption is high. Further, the urging force of the spring 121 requires a large urging force in order to oppose the fuel pressure of the pump chamber 35 at the time of fuel discharge, so that power consumption is further increased. Therefore, in the case of the solenoid valve 51 that is a valve that is closed when energized and that is opened internally as in this embodiment, it is possible to effectively reduce power consumption.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

For example, in the present embodiment, the solenoid valve 51 is energized while fuel is being sucked into the pump chamber 35. However, the present invention is not limited to this. The solenoid valve 51 may be energized, or at least when the needle valve 53 is seated to energize to apply the valve closing force. If power is supplied to the solenoid valve 51 immediately before the end of fuel suction, the power supply time can be further reduced, so that power consumption can be further reduced. In addition, the needle valve 53
Due to the pressure in the pump chamber 35, the valve seat 54 is seated,
The spring 59 does not need to be provided because the spring 59 is separated from the valve seat 54.

[0031]

According to the first aspect of the present invention, since power is supplied to the solenoid valve while the valve body is seated on the valve seat, the power supplied to the solenoid valve can be reduced, and power consumption can be reduced. The power can be reduced. Further, since the power can be reduced, the booster circuit and the like can be omitted, and it is not necessary to increase the size of the excitation coil and the like of the solenoid valve, so that the solenoid valve can be downsized.

According to the second aspect of the invention, the same effect as that of the first aspect of the invention is obtained, and the valve body is guided in the moving direction by the spring, so that the valve body can be prevented from wobbling. The movement of the valve body can be stabilized.

According to the third aspect of the present invention, the same effect as that of the first or second aspect of the present invention can be obtained, and the discharge of fuel can be easily terminated only by stopping the energization of the solenoid valve. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a fuel supply pump according to the present invention.

FIG. 2 is a configuration diagram schematically showing a fuel supply pump according to FIG. 1;

FIG. 3 is a configuration diagram schematically showing a solenoid valve that is closed when energized and that is opened internally.

FIG. 4 is a graph illustrating the relationship between plunger displacement and solenoid valve operation.

FIG. 5 is a diagram for explaining a difference from the present embodiment, and is a configuration diagram schematically showing a solenoid valve that is an energized-open type and an internally opened valve.

FIG. 6A is a configuration diagram schematically showing a conventional fuel supply pump, and FIG. 6B shows a relationship between plunger displacement and solenoid valve operation in the fuel supply pump of FIG. It is a graph.

[Explanation of symbols]

 2 High pressure pump (fuel supply pump) 16 Discharge valve 17 Suction valve 20 Return passage 21 Plunger 35 Pump chamber 45 Low pressure passage 51 Solenoid valve 52 Valve hole 53 Needle valve (valve element) 54 Valve seat 59 Spring

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-71338 (JP, A) JP-A-10-153157 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 59/34 F02M 59/36 F02M 51/00 F16K 31/06

Claims (3)

(57) [Claims] An intake valve, a discharge valve, a return passage for returning a part of fuel in a pump chamber to a low-pressure passage, and an electromagnetic valve provided in the return passage and generating a biasing force in a valve closing direction by energization. A fuel supply pump, wherein the solenoid valve has a valve seat formed with a valve hole communicating with the pump chamber, and a valve body that moves toward the pump chamber by the pressure of the pump chamber during the suction stroke and seats on the valve seat. Equipped with a suction stroke
The fuel supply pump according to any one of claims 1 to 3, wherein the solenoid valve is energized when the valve is seated on the valve seat and the valve is closed. 2. The fuel supply pump according to claim 1, wherein the solenoid valve includes a spring for urging the valve body in a seating direction. 3. The energization of the solenoid valve is started during a suction stroke.
The fuel supply pump according to claim 1 , wherein the end of fuel discharge is controlled by stopping energization of the solenoid valve during a discharge stroke .