JPH094471A - Injection time control device for fuel injection pump - Google Patents

Abstract

PURPOSE: To improve the responsiveness of an injection time control device for a fuel injection pump, and to restrict unevenness of the characteristic of products, and to reduce the cost. CONSTITUTION: An injection time control device is provided with a timer cylinder 20, a timer high-pressure chamber 22 and a timer low-pressure chamber 24 provided in both ends of the timer cylinder 20, a timer piston 21 to be moved in response to a pressure difference between both the chambers so as to adjust the injection time of the fuel through a slide pin 19, and a hydraulic control valve 27 for changing the pressure of the high-pressure chamber 22 or the low- pressure chamber 24. In this injection time control device, the hydraulic control valve 27 is provided with a conical-shaped valve seat 37 and a valve needle 43 having a conical surface 38 for opening and closing the valve seat 37. A flow rate adjusting throttle 39 is provided in an inlet flow passage 41 (or an outlet flow passage 42) to the hydraulic control valve 27. A filter 34 is provided. With this valve structure, since a large valve opening is obtained by the fine lift of the valve needle 43, the responsiveness is improved, and in the other hand, growth of a difference between each product can be restricted by the easy adjustment of the flow quantity adjusting throttle 39.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection pump mainly used in a diesel engine, and more particularly to a fuel injection pump of a distribution type, which controls fuel injection timing in response to a command from an electronic control unit. The present invention relates to an injection timing control device characterized by a hydraulic control valve for freely adjusting.

[0002]

2. Description of the Related Art For example, as disclosed in Japanese Utility Model Laid-Open Publication No. 63-110640, a distribution type fuel injection pump for a diesel engine employs a plunger for pumping fuel to control fuel injection timing. A timer piston for changing the timing of the driving cam is provided.
Then, by adjusting the hydraulic pressure acting on the chambers by means such as a hydraulic control valve provided between the chambers on both sides of the timer piston, the timer piston is moved to adjust the fuel injection timing. You can do it.

A device in which a hydraulic control valve is electromagnetically opened and closed by a solenoid coil is described, for example, in Japanese Utility Model Laid-Open No. 56-173736. By controlling the energization or interruption of the solenoid coil in the solenoid valve as such a fuel oil pressure control valve using an electronic control device, the oil pressure acting between the chambers on both sides of the timer piston is changed to change the timer piston. If the position of is adjusted, the fuel injection pump can be electronically controlled.

An example of the hydraulic control valve is shown as 50 in FIG. By controlling the energization of the coil 54, communication / interruption between the flow path 55 and the flow path 56 is determined. That is, when the coil 54 is energized, the armature 52 integrated with the valve needle 51 is attracted to the stator 53 against the spring force of the spring 57, and the surface 58 of the valve needle 51 contacts the stopper 59. The flow path 55 and the flow path 56 communicate with each other and move to the right in the middle direction to open the valve. The lift amount l ₅ at that time is l ₅ = 0.7 mm. In this case, armature 5
2 is an air gap l ₆ between the stator 53 and the stator 53.
Since there is a relation of ₆ = l ₅ +0.1 mm, l ₆ = 0.8 mm when the valve is closed and l ₆ = 0.1 mm when the valve is open. When the power supply to the coil 54 is stopped, the spring 57
The armature 52 integrated with the valve needle 51 is moved leftward in the figure by the spring force of, and the hydraulic control valve 50 is closed.

With the recent tightening of exhaust gas regulations, Japanese Patent Laid-Open No.
As described in Japanese Patent Application Laid-Open No. 2-101865, since high speed responsiveness of the valve needle 51 is required, it has been required to perform rotation synchronization control. Since the hydraulic control valve 50 takes a long time from when the coil 54 is energized to when it is opened, that is, the valve opening response is extremely poor, a hydraulic control valve having a good valve opening response is desired.

[0006] It is necessary to shorten the valve opening response of the valve needle 51, that is, the time from when the coil 54 is energized until a sufficient suction force is generated. For that purpose, it is effective to reduce the number of coil turns N as shown in FIG. However, if the number of coil turns N is reduced, a large amount of current is required to obtain the same attraction force, which causes another problem that the cost of the drive circuit increases.

On the other hand, as shown in FIG. 10, if the air gap l ₆ is made small, a large suction force can be obtained with a small current, but in that case, the lift amount l ₅ needs to be made small. Another problem arises in that a sufficiently large flow passage area cannot be obtained between the flow passages 55 and 56 due to the notch 51a of the valve needle 51.

Therefore, as shown in FIG. 3, in the hydraulic control valve 27 for the injection timing control device of the fuel injection pump, a sufficient flow passage area can be obtained with a lift amount smaller than the conventional valve lift amount. It is conceivable to have a valve structure comprising a valve cylinder 44 having a conical valve seat 37 and a valve needle 43 having a conical surface 38 that is inserted into it and moved by the control device and that opens and closes the valve seat 37. . According to this approach, the diameter of the sealing edge, which is the circular line of contact between the conical surface 38 of the valve needle and the conical valve seat 37 when closing the valve, is equal to or greater than the diameter of the valve needle 43. Since it is set to be slightly smaller, a small valve needle lift results in a larger valve opening.

However, in the hydraulic control valve according to the above-described trial, the influence of the setting error of the valve lift amount on the flow rate characteristic of the hydraulic control valve becomes large, so that the difference between individual timers (variation of product characteristics) is reduced. In this case, it is necessary to set a highly precise setting for the valve lift amount of the hydraulic control valve. In other words, since a high dimensional accuracy and high accuracy assembly jig are required in the processing of the components that make up the hydraulic control valve, it is easy to increase the flow rate of the hydraulic control valve and adjust the flow rate outflow from the timer high pressure chamber. There was a problem that it was incompatible to do.

[0010]

SUMMARY OF THE INVENTION The present invention solves these problems by a very simple means in view of the above-mentioned prior art and some problems in an attempt to improve it. (EN) An injection timing control device for a fuel injection pump, which is excellent in responsiveness due to a large valve opening when the hydraulic control valve is opened, but has little individual difference in operating characteristics and which can be manufactured at low cost. It is an object.

[0011]

SUMMARY OF THE INVENTION Therefore, according to the present invention, in an injection timing control device for a fuel injection pump, a hydraulic control valve is formed in a valve body and a substantially conical shape on one end side formed in the valve body. A valve cylinder having a valve seat, and a valve needle slidably inserted into the valve cylinder and moved by a control device, and at least a part of which has a conical surface for opening and closing the conical valve seat. And a diameter of a sealing edge, which is a circular line where the conical surface of the valve needle and the conical valve seat contact each other when the valve is closed, is substantially equal to the diameter of the valve needle. By setting the above, it is possible to obtain a sufficiently large flow passage area with a smaller lift amount than before, and the flow rate adjustment throttle for adjusting the amount of oil flowing into the hydraulic control valve is provided as described above. In combination with pressure control valve, to solve the above problems by suppressing the inter-individual differences in the flow characteristics of the hydraulic control valve.

Further, in the present invention, by providing a filter between the low pressure chamber and the flow path on the side surface of the valve needle,
This prevents foreign matter from clogging the flow passage and closing the valve, and clogging of the flow control throttle provided in the flow passage. Further, in the present invention, the movement of the valve needle is ensured by communicating the flow paths at both ends of the valve needle.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As a premise for explaining an injection timing control device for a fuel injection pump of the present invention, particularly a hydraulic control valve used therein, two timer systems of a fuel injection pump to which it is applied, That is, the configurations of the timer high pressure chamber control system and the timer low pressure chamber control system will be described. In addition, in the embodiment of the present invention, the same reference numerals are attached to substantially the same components as those of the above-mentioned conventional example.

First, the structure of the distributed fuel injection pump 1 of the timer high pressure chamber control system shown in FIG. 1 will be described. The drive shaft 2 is rotationally driven by an engine (not shown) in synchronization with the rotation of the engine. Drive shaft 2
The signal rotor 3 is coaxially attached to
A plurality of convex teeth are formed on the outer circumference thereof. Reference numeral 4 denotes a rotation angle sensor which faces the outer periphery of the signal rotor 3, generates a pulse signal according to the engine speed by electromagnetic induction of the convex teeth of the signal rotor 3, and outputs the pulse signal to the electronic control device 5. I do. Here, the electronic control unit 5 is the spill valve 1
8 and a drive circuit for driving the hydraulic control valve 50.
A face cam 7 for driving a plunger 6 for pumping fuel and a vane pump 8 as a fuel feed pump are connected to the drive shaft 2. The face cam 7 is integrated with the plunger 6 and is a roller 11 rotatably supported on a roller ring 10 by a spring 9.
Pressed against.

Therefore, when the face cam 7 is rotationally driven by the drive shaft 2, the convex portion of the face cam 7 rides on the roller 11, and the face cam 7 itself and the plunger 6 integrated with it are rotated. Along with this, the plunger 6 reciprocates in the axial direction. Since the plunger 6 is inserted into the cylinder bore 12a of the pump cylinder 12 and forms the pressure chamber 13 at its tip, the volume of the pressure chamber 13 is expanded or contracted by the component of the reciprocating motion of the plunger 6, and at the same time the rotational motion Depending on the component, the suction side port and the discharge side port opening to the pressure chamber 13 are sequentially switched to communicate with each other.

The fuel discharged from the discharge port 14 of the feed pump 8 and pressurized to about 10 atmospheres is stored in the fuel chamber 15. The fuel is sucked into the pressure chamber 13 and pressurized to a high pressure to a predetermined pressure. The fuel is injected under pressure to the fuel injection valve 16 and injected into the combustion chamber of the engine (not shown). The pressure chamber 13 is provided in the housing 17 of the fuel injection pump 1.
Is equipped with a spill valve 18 to release the pressure of
By opening and closing the spill valve 18 by the electronic control unit 5, the fuel injection start timing, injection amount, and injection rate can be controlled.

A cylindrical outer peripheral surface 10a of the roller ring 10.
Can rotate about the axis of the drive shaft 2 within a predetermined angle range. The rotation causes the position of the roller 11 to move in the rotation direction.
The timing at which the convex portion of the vehicle rides on the roller 11 changes, whereby the fuel injection timing can be changed. In order to rotate the roller ring 10, a slide pin 19 extends from the roller ring 10 downward in FIG. 1, and a lower end of the slide pin 19 is formed in a timer cylinder 20 formed in a housing 17.
It is engaged with a timer piston 21 which is fitted so as to be able to reciprocate in the left and right directions inside.

In FIG. 1, the timer high-pressure chamber 22 on the right side of the timer piston 21 communicates with the fuel chamber 15 via the throttle 23 and the check valve 63, and receives the fuel pressurized by the feed pump 8. Although the hydraulic pressure pushes the timer piston 21 to the left, a timer spring 25 is mounted in the timer low pressure chamber 24 on the left side of the timer piston 21 in opposition thereto. Timer low pressure chamber 24
Communicates with the suction port 26 of the feed pump 8,
It is always low pressure during operation. The hydraulic pressure of the fuel acting on the timer high-pressure chamber 22, that is, the supply pressure, changes in magnitude depending on the engine speed, and thus the rotational speed of the drive shaft 2. Therefore, the urging force by the hydraulic pressure and the timer spring 25 are used.
The timer piston 21 moves to a position in which the urging force of the fuel is balanced and the roller ring 10 is rotationally adjusted via the slide pin 19, so that the fuel injection timing changes according to the engine speed.

In the conventional electronically controlled timer (electronically controlled injection timing control device), the hydraulic control valve 50 composed of the solenoid valve as described above is inserted between the timer high pressure chamber 22 and the timer low pressure chamber 24. By electrically connecting the hydraulic control valve 50 to the electronic control unit 5 to control opening and closing,
The hydraulic pressure in the timer high pressure chamber 22 is partially converted to the timer low pressure chamber 24.
The position of the timer piston 21 and the position of the roller ring 10 in the direction of rotation are changed to control the fuel injection timing. The present invention relates to the hydraulic control valve 50, the timer high pressure chamber 22 and the timer low pressure chamber 24.
The structure of the passage (including the flow passage on the side surface of the valve needle 51 shown in FIG. 8) that communicates with and is improved.

As described above, the timer device (injection timing control device) 28 for the face cam pressure feed type distributed fuel injection pump 1 shown in FIG. 1 includes the timer cylinder 20, the timer piston 21, and the timer piston 21. It comprises a roller ring 10 interlocked with, a hydraulic control valve 50 for controlling the position of the timer piston 21, and the like. Note that the drive shaft 2 and the timer piston 21 are drawn in parallel in FIG. 1 for easy understanding, but the latter is in a direction perpendicular to the former in order to operate as described above. Crosses Similarly, the axis of the feed pump 8 is also shown rotated 90 ° with respect to the drive shaft 2. .

The rotation speed sensor 4 is composed of the roller ring 1
It is carried on the outer peripheral surface 10a of No. 0, and its output signal is inputted to the electronic control unit 5, but the control unit 5 is also shown as a TDC signal from the engine as shown in FIG. A point signal, an accelerator opening signal indicating the magnitude of the load on the engine, an output signal from a water temperature sensor detecting a cooling water temperature, etc. are input.

Next, as another timer type fuel injection pump, the structure of the timer type low pressure chamber control type distribution type fuel injection pump shown in FIG. 2 will be described. Since a considerable part of the structure shown in FIG. 2 is substantially the same as that of the distributed fuel injection pump 1 of the timer high pressure chamber control system shown in FIG. 1, the same reference numerals are given to them. I will decide.

In FIG. 2, the timer high-pressure chamber 22 on the right side of the timer piston 21 is always in communication with the fuel chamber 15 via the throttle 23, and receives the fuel pressurized to about 10 atmospheres by the feed pump 8. . Timer piston 2
The timer spring 2 is provided in the timer low-pressure chamber 24 on the left side of 1.
5 is installed. The timer low pressure chamber 24 communicates with the suction port 26 of the feed pump 8 via the throttle 64, and the amount of inflow from the fuel chamber 15 is controlled by the hydraulic control valve 27 of the present invention.
The pressure in the timer low-pressure chamber 24 (range from atmospheric pressure to 10 atmospheric pressure, which is the same as the fuel chamber 15) is determined by adjusting by. Then, the timer high pressure chamber 22 and the timer low pressure chamber 24
The force generated by the pressure difference between
The position of the timer piston 21 is determined by the balance with the urging force of 5. The present invention relates to a hydraulic control valve 50 used in the distributed fuel injection pump 1'of the timer low pressure chamber control system shown in FIG. 2 and a passage (a valve needle (Including the side channels).

Next, a first embodiment of the combination of the hydraulic control valve 27 and the flow rate adjusting throttle 39, which is a feature of the present invention, will be described with reference to FIG. The hydraulic control valve 27 of the present invention can replace the hydraulic control valve 50 in the fuel injection device shown in FIGS. 1 and 2. The flow rate adjustment diaphragm 39 shown in FIG.
The timer high pressure chamber 22 is provided in the flow passage 41 that communicates with the flow passage 60 formed inside the valve body 40. The system illustrated in FIG. 3 is applied to the timer high pressure chamber control method shown in FIG. To be done.

More specifically, a valve cylinder 44, on which a valve needle 43 is slidable, is provided at the center of the valve body 40.
Is formed, and the side surface of the flow channel 60 is opened in an annular shape.
A flow path 61 that opens as the valve seat 37 is formed at the left end. The channel 60 is connected to the timer high pressure chamber 22 via the channel 41.
Also, the flow path 61 is connected to the timer low pressure chamber 24 via the flow path 42.
It communicates with each. The flow rate adjusting diaphragm 39, which is a feature of the embodiment, is provided in the flow path 41. The flow rate adjustment throttle 39 is provided in the flow path 6 that opens inside the valve body 40.
It may be provided between 1 and the timer low pressure chamber 24. In the case of the distributed fuel injection pump of the timer low pressure chamber control system shown in FIG. 2, since the flow passage 60 and the flow passage 61 are connected to the fuel chamber 15 and the timer low pressure chamber 24, respectively, the flow rate adjustment throttle 39
Is provided in the flow path that connects the fuel chamber 15 and the hydraulic control valve 27.

Inside the valve cylinder 44 at the center of the valve body 40, a valve needle 43 which is movable in the left-right direction is disposed so as to be slidable. An armature 52 is fixed by press fitting to the right end side of the valve needle 43 in the figure, and the armature 52 faces the stator 53 with a space (air gap) l ₂ . Further, a spring chamber 62 is provided inside the stator 53, and the spring 5
7 are provided. The armature 52 is constantly urged leftward in the figure by the elasticity of the spring 57. Therefore, when the coil 54 is not energized, the tip of the valve needle 43 is in close contact with the valve seat 37, the hydraulic control valve 27 is closed, and the valve between the timer high pressure chamber 22 and the timer low pressure chamber 24 is closed. Communication is cut off.

When the coil 54 is energized, the armature 5
2 is attracted to the stator 54 and moves to the right in the figure against the spring force of the spring 57, the tip of the valve needle 43 integrated with the armature 52 separates from the valve seat 37, and the hydraulic control valve 27 opens. The valve state is established, and the timer high pressure chamber 22 and the timer low pressure chamber 24 communicate with each other. The lift amount l ₁ of the valve needle 43 at that time is l ₁ = 0.15 mm, and the valve needle 4
The lift of the valve needle 43 is completed at the position where the right shoulder surface 47 of No. 3 contacts the stopper 59. At that time, the air gap l ₂ was l ₂ = 0.25 mm when the valve was closed, but became l ₂ = 0.1 mm when the valve was opened.

When the coil 54 is damaged, the most advanced fuel injection timing is better than the most retarded fuel injection timing. Therefore, as described above, the hydraulic control valve 27 is normally closed (normally closed). ) Is configured to be.

The coil 54 is wound around a coil bobbin 49, which is housed in a casing 39. The left end of the casing 39 in the figure is fixed to the valve body 40 by caulking, and the right end of the casing 39 is also fixed to the stator 53 by caulking.

Next, the structure of the tip of the valve needle 43 will be described with reference to FIG. It should be noted that FIG. 4 is a diagram showing when the valve is open and FIG. 3 is a diagram showing when the valve is closed. A flow passage 60 is formed inside the valve body 40 so as to enclose the valve needle 43, and a flow passage 61 is provided on the downstream side of the valve needle 43. The valve needle 43 connects or disconnects.

The valve needle 43 has a valve diameter d ₁ of 5.0 mm and an inclination angle θ ₁ = 93 ° of the conical surface 38 at the tip of the valve needle, and the conical surface of the valve seat 37 on the flow path side has a right end diameter d _2. 5.
The inclination angle θ ₂ is 90 ° at 1 mm, and the diameter d of the channel 61 is
₃ is set to 4.4 mm. Here, if the value of the flow path diameter d ₃ is too large as compared with the value of the right end diameter d ₁ , the area of the valve seat 37 becomes insufficient and the valve seat surface wears. If it is too small, a small amount of fuel leaks due to the roughness of the conical surface 38 of the tip end of the valve needle 43 even when the valve needle 43 is seated. Therefore, the fuel pressure causes the valve needle 43 to move to the right in the figure. The force pushing to becomes large and the valve closes poorly.

Since the structure of the tip of the valve needle 43 is as described above, when the valve is closed, the sealing edge 36 of the conical surface 38 is in close contact with the surface of the valve seat 37 and the flow paths 60 and 61 are shut off from each other. It

Further, as a modification of the example shown in FIG. 4, the tip of the valve needle 43 may be as shown in FIG. That is,
The conical surface at the tip of the valve needle 43 changes its angle in two steps to form a seal edge 35 having a valve diameter d ₄ = 4.9 mm, and the relationship of the inclination angles is θ ₃ <θ ₂ <θ ₁ . . To give a specific example of the numerical value of the tilt angle, θ ₁ = 93 °, θ ₂
= 90 ° and θ ₃ = 80 °.

Since the hydraulic control valve 27 of the first embodiment has such a valve structure, it can be opened with a smaller lift amount of the valve needle 43 as compared with the conventional hydraulic control valve 50 shown in FIG. Sometimes a sufficiently large opening area can be obtained.

The area of the flow control throttle 39 of the first embodiment is equal to the lift amount of the valve needle 43 of the hydraulic control valve 27.
It is set to be smaller than the opening area at full lift. Further, the area of the flow rate adjusting diaphragm 39 of the first embodiment is set to be larger than the area of the diaphragm 23 shown in FIGS.

Returning to FIG. 3 again, a filter 34 having an opening of 0.1 mm is provided in the flow path 41 at a position on the upstream side of the flow path 60 and the flow rate adjusting throttle 39 (on the side of the timer high pressure chamber 22).
Is provided. The filter 34 is provided to prevent foreign matter from being caught between the surface of the valve seat 37 and the conical surface 38 of the tip of the valve needle 43 and to be in a normally open state. It is also for preventing clogging of 39. Therefore, the opening of the filter 34 is 0.1 mm, which is smaller than the area of the flow rate adjusting throttle 39 and smaller than the lift amount l ₁ of the valve needle 43.

When the hydraulic control valve 27 is applied to the fuel injection pump 1'of the timer low pressure chamber control system shown in FIG. 2, the hydraulic pressure of the timer low pressure chamber 24 changes within the range of atmospheric pressure to 10 atmospheric pressure. Therefore, the hydraulic pressure in the flow path 61 also changes within the same pressure range. Therefore, in this case, in order to avoid the influence of the pressure change, the communication passage 33 is connected to the valve body 40.
However, the stopper 59 is provided with the flow passage 32 so that the spring chamber 62 and the flow passage 61 are communicated with each other to maintain the same pressure.

In the present embodiment, the filter 34
Although it is provided in the flow path 41, it may be installed anywhere on the way from the fuel chamber 15 through the timer high pressure chamber 22 to the flow rate adjusting throttle 39. Further, in the case of the fuel injection pump of the timer low pressure chamber control system shown in FIG.
It may be installed at any position on the way to 9.

Next, the operation of the first embodiment will be described with reference to FIGS. When the coil 54 is energized by the electronic control unit 5, the valve needle 43 moves to the valve opening position and the hydraulic control valve 27 opens. As a result, the oil (fuel) in the timer high pressure chamber 22 flows into the timer low pressure chamber 24, the pressure in the timer high pressure chamber 22 decreases, and the timer piston 21 moves to the right in the figure by the biasing force of the spring 25, and the injection timing Changes in the retard direction.

It should be noted here that the hydraulic control valve 27
The amount of oil flowing from the timer high pressure chamber 22 to the timer low pressure chamber 24 via the valve is not adjusted by the opening area at full lift generated by the opening of the valve needle 43 of the hydraulic control valve 27, but by the flow rate adjusting throttle. That is, the amount is adjusted according to the size of the opening area of 39.

Next, the coil 5 is activated by the operation of the controller 5.
4 is stopped, the valve needle 43 is moved to the closed position by the urging force of the spring 57, and the hydraulic control valve 2
7 is closed, and the communication between the timer high pressure chamber 22 and the timer low pressure chamber 24 is cut off. As a result, the timer high pressure chamber 22
Rises to the pressure of the fuel chamber 15, the timer piston 21 moves leftward in FIG. 3, and the injection timing changes in the advance direction.

As is clear from the above description, the lift amount l is determined from the shape of the seat portion of the hydraulic control valve 27 of the first embodiment, that is, the conical surface 38 of the valve needle 43 and the valve seat 37.
_{Since 1} may be as small as 0.15 mm, the air gap l ₂ before the coil 54 sucks the armature 52
Since it also becomes smaller, the number of coil turns N can be reduced. Therefore, the opening response of the hydraulic control valve 27 is improved.

A second embodiment of the combination of the hydraulic control valve 27 and the flow rate adjusting throttle 39, which is a feature of the present invention, will be described with reference to FIGS. 6 and 7. Since most of the structure shown in FIG. 6 is substantially the same as that of the hydraulic control valve 27 of the first embodiment shown in FIG. 3, they are designated by the same reference numerals.

A valve cylinder 45 is formed in the center of the valve body 31, and the flow passage 2 is formed in the body 31.
9 and 30 are provided, each of which opens upward in the right side of the cylinder 45 and downward in the left side of the cylinder 45 in FIG. The flow passage 29 communicates with the timer high pressure chamber 22 (in the case of the timer high pressure chamber control system of FIG. 1) or the fuel chamber 15 (in the case of the timer low pressure chamber control system of FIG. 2), and the flow passage 30 is the flow passage 30. Is in communication with.

The flow rate adjusting diaphragm 39 is provided in the middle of the flow path 29. Then, the flow rate adjusting diaphragm 3 in the middle of the flow path 29.
9, the lift amount l ₃ = 0.15 on the side of the timer high pressure chamber 22.
mm and the opening smaller than the inner diameter of the flow rate adjusting diaphragm 39.
A 1 mm filter 65 is provided. Of course, the flow rate adjusting throttle 39 and the filter 65 may be installed at positions other than the inside of the valve body 31 as long as the filter 65 is closer to the timer high pressure chamber 22 than the flow rate adjusting throttle 39.

In the valve cylinder 45 formed in the center of the valve body 31, a valve needle 66 movable in the left-right direction is inserted in a liquid-tight manner so that it can slide. An armature 52 is press-fitted into and integrated with the right end side of the valve needle 66 in the figure, and the armature 52 faces the stator 53 with an interval (air gap) l ₄ . When the coil 54 is not energized, the valve needle 66 is pushed to the closed position by the biasing force of the spring 57, and the hydraulic control valve 27 is closed. As described above, the hydraulic control valve 27 of the second embodiment is also normally closed as in the first embodiment.

When the coil 54 is energized by the electronic control unit 5 shown in FIG. 1, the armature 52 moves to the spring 57.
Is attracted by the stator 53 against the urging force of 1 ₃ = 0.
Lift by 15mm and open the valve. The opening area of the flow rate adjustment throttle 39 is set so as to be smaller than the opening area when the lift amount of the valve needle 66 is full lift. The amount of oil flowing out to the flow passage 30 in the valve body 31 is adjusted according to the opening area of the flow rate adjusting throttle 39. At that time, l ₄ = 0.1 mm.

Then, similarly to the case of the first embodiment shown in FIG. 3, the passage 32 provided in the stopper 48 connects the spring chamber 62 and the flow passage 30 to each other, and further the flow provided in the valve body 31. Valve body chamber 6 by way 67
8 and the flow path 30 are communicated with each other so that the pressure of the timer low pressure chamber 24 does not affect the operation of the valve needle 66.

Next, the seat portion of the valve needle 66 in the second embodiment will be described with reference to FIG. Note that FIG.
Shows a valve open state unlike FIG. Valve body 3
The conical surface of the valve seat 69 on the first side has an inclination angle θ ₅ of 93 °, and the conical surface 70 formed in the middle of the valve needle 66 has an inclination angle θ ₄ of 90 °. Here, the diameter of the valve needle 66 is such that d ₆ is 5.0 mm and d ₅ is 5.5 mm.

Therefore, when the valve needle 66 is pushed to the closed position by the urging force of the spring 57, the seal edge 71 of the valve seat 69 and the conical surface 70 of the valve needle come into close contact with each other and the flow passage 29 and the flow passage 30 are connected. Cut off communication between them. Further, the conical surface of the valve seat 69 has two stages, and the diameter of the seal edge 71 is d.
May be slightly larger than ₆ .

The combination of the hydraulic control valve 27 and the flow rate adjusting throttle 39 of the second embodiment having such a structure is different from that of the first embodiment in that the valve seat 69 forming the seat portion and the cone of the valve needle are formed. There is an advantage that the processing of the surface 70 becomes easy.

The present invention can be applied not only to the face cam pressure feeding type distribution type fuel injection pump as in the above embodiment, but also to a well-known inner cam pressure feeding type distribution type fuel injection pump itself. .

[0053]

According to the present invention, the structure of the valve body of the hydraulic control valve in the injection timing control device of the fuel injection pump is slightly changed, and the flow control throttle is provided in a part of the flow path of the hydraulic control valve. By extremely simple means, the response of the injection timing control of the fuel injection pump is improved, while it is possible to manufacture it at a low cost without causing a large individual difference.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a system configuration of a distribution type fuel injection pump and an injection timing control device attached to the distribution fuel injection pump by a timer high pressure chamber control system.

FIG. 2 is a cross-sectional view showing a system configuration of a distribution type fuel injection pump and an injection timing control device by a timer low pressure chamber control system attached thereto.

FIG. 3 is a sectional view showing a first embodiment of the hydraulic control valve in the injection timing control device, which is a feature of the present invention.

FIG. 4 is a sectional view showing a main part of a hydraulic control valve in the injection timing control system of the first embodiment shown in FIG.

5 is a sectional view showing a modification of the first embodiment shown in FIG.

FIG. 6 is a sectional view showing a second embodiment of the hydraulic control valve in the injection timing control device, which is a feature of the present invention.

FIG. 7 is a sectional view showing a main part of the hydraulic control valve according to the second embodiment shown in FIG.

FIG. 8 is a sectional view showing a hydraulic control valve in a conventional injection timing control device.

FIG. 9 is a diagram showing the relationship between the number of turns of the coil and the suction force, and thus the valve opening response of the hydraulic control valve.

FIG. 10 is a diagram showing a relationship between an air gap and a suction force.

[Explanation of symbols]

1 ... Distribution type fuel injection pump by timer high pressure chamber control system 1 '... Distribution type fuel injection pump by timer low pressure chamber control system 2 ... Drive shaft 5 ... Electronic control device 6 ... Plunger 7 ... Face cam 8 ... Feed pump 9 ... Spring 10 ... Roller ring 12 ... Pump cylinder 13 ... Pressure chamber 14 ... Feed pump discharge port 15 ... Fuel chamber 16 ... Fuel injection valve 17 ... Pump housing 18 ... Spill valve 19 ... Slide pin 20 ... Timer cylinder 21 ... Timer piston 22 ... Timer high pressure chamber 24 ... Timer low pressure chamber 25 ... Timer spring 26 ... Feed pump suction port 27 ... Hydraulic control valve 28 of the present invention ... Injection timing control device (timer device) 30 ... Flow path 31 ... Hydraulic pressure of the second embodiment Valve body 33 of control valve ... Communication passage 34 ... Filter 35, 36 ... Rule edge 37 ... Valve seat 38 ... Conical surface of valve needle tip 39 ... Flow rate adjusting throttle 40 ... Valve body of hydraulic control valve of the first embodiment 43 ... Valve needle (first embodiment) 44, 45 ... Valve cylinder 47 ... Valve Needle shoulder surface 48 ... Stopper 50 ... Conventional hydraulic control valve 51 ... Valve needle (conventional technology) 52 ... Armature 53 ... Stator 54 ... Coil 57 ... Spring 59 ... Stopper 65 ... Filter 66 ... Valve needle (second embodiment) 69 ... Valve seat 70 ... Conical surface of valve needle 71 ... Seal edge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Moriyasu Goto 14 Iwatani Shimohakaku-cho, Nishio-shi, Aichi Japan Auto Parts Research Institute (72) Inventor Yukihiro Shinohara 1-1-chome, Showa-cho, Kariya city, Aichi Japan Denso Co., Ltd.

Claims (11)

[Claims] 1. A timer cylinder, a timer high pressure chamber formed at both ends of a timer cylinder, and a timer, which are attached to a fuel injection pump for an internal combustion engine for injecting fuel by injecting fuel to a fuel injection valve by reciprocating movement of a plunger. A low pressure chamber,
At least the timer high pressure chamber and the timer low pressure chamber, which are slidably inserted into the timer cylinder and move according to the pressure difference between the timer high pressure chamber and the timer low pressure chamber to adjust the fuel injection timing. In an injection timing control device including a hydraulic control valve for changing one pressure, the hydraulic control valve includes a valve body, and a valve seat formed in the valve body and having a substantially conical valve seat on one end side. A valve cylinder including: a valve needle slidably inserted into the valve cylinder and moved by a control device; and at least a part of which has a conical surface for opening and closing the conical valve seat, And a flow rate adjusting throttle for adjusting the amount of oil flowing through the hydraulic control valve, and
The diameter of the seal edge, which is a circular line that makes the conical surface of the valve needle and the conical valve seat contact each other when the valve is closed, is set to be substantially equal to the diameter of the valve needle. A characteristic injection timing control device for a fuel injection pump. 2. In order to prevent the valve needle from moving due to a difference in pressure acting on both ends of a portion of the valve needle inserted into the valve cylinder, a pressure on one end side of the valve needle is adjusted. The injection timing control device for a fuel injection pump according to claim 1, further comprising a communication passage that leads to the other end side. 3. The injection timing control device for a fuel injection pump according to claim 1, wherein the flow rate adjusting throttle is provided upstream of the hydraulic control valve. 4. The injection timing control device for a fuel injection pump according to claim 1, wherein the flow rate adjusting throttle is provided on the downstream side of the hydraulic control valve. 5. The injection timing control device for a fuel injection pump according to claim 3, wherein the area of the flow rate adjusting throttle is set smaller than the opening area of the valve needle of the hydraulic control valve at the time of full lift. 6. The injection timing control device for a fuel injection pump according to claim 5, further comprising a filter provided upstream of the hydraulic pressure control valve and the flow rate adjusting throttle. 7. The opening of the filter is smaller than the opening area of the valve needle of the hydraulic control valve at the time of full lift,
7. The injection timing control device for a fuel injection pump according to claim 6, wherein the area is set smaller than the area of the flow rate adjusting throttle. 8. The fuel injection according to claim 1, wherein the opening direction of the valve needle of the hydraulic control valve is opposite to the flowing direction of oil passing through the hydraulic control valve when the valve is opened. Pump injection timing control device. 9. The injection timing control device for a fuel injection pump according to claim 8, wherein a conical surface is formed on the tip side of the valve needle. 10. The injection of the fuel injection pump according to claim 1, wherein a valve opening direction of the valve needle and a flow direction of oil passing through the hydraulic pressure control valve at the time of valve opening coincide with each other. Timing control device. 11. The injection timing control device for a fuel injection pump according to claim 10, wherein a conical surface is formed on the rear end side of the valve needle.