JPS6128029Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection timing adjustment device for a distributed fuel injection system.

Generally, in an injection type internal combustion engine such as a diesel engine, a fuel injection timing adjustment device is used because it is necessary to advance the fuel injection timing as the rotational speed increases. A fuel injection timing adjustment device for a distributed fuel injection device includes a timer piston responsive to fuel pressure in a fuel injector housing supplied with fuel by a fuel supply pump driven in relation to engine speed; The displacement of the timer piston is transmitted to the injection timing control member to control the fuel injection timing.

However, the fuel injection timing characteristics when using the above-mentioned conventional fuel injection device are mainly those shown in FIG. Kaisho
56-451265 and Utility Model Application Publication No. 56-45127, but the above-mentioned devices change uniquely in response to changes in rotational speed, and do not change in response to operating conditions other than rotational speed. I couldn't let it go.

The present invention has been developed in view of the above, and as shown in Fig. 4 in a distributed fuel injection system, the fuel injection timing characteristic can be changed in two stages according to the operating condition of the engine. An object of the present invention is to provide a fuel injection timing adjustment device having the following.

This purpose, according to the present invention, includes an engaging member that engages at a predetermined position with an injection timing control member during injection timing control, and a spring that opposes a moving force in an advance direction that is applied to the engaging member. This is achieved by using the spring to reduce the speed of movement of the injection timing control member in the advance direction after the injection timing control member and the engagement member are engaged.

The present invention will be explained below with reference to examples.

Fig. 2 is a partial cross-sectional view of a distributed fuel injection device to which an embodiment of the present invention is applied, and Fig. 3 is a partial cross-sectional view of a distribution type fuel injection device to which an embodiment of the present invention is applied.
FIG.

Fuel is fed from a fuel tank 1 to a chamber 4 in a fuel injection device housing 3 by a fuel supply pump 2 which is rotated by a drive shaft (not shown) at the engine speed. A pressure regulating valve 5 is connected in the communication path between the discharge side and the suction side of the fuel supply pump 2, and the pressure regulation valve 5 causes the discharge side pressure of the fuel supply pump 2, that is, the fuel pressure in the chamber 4, to correspond to the engine speed. ing.

Barrel 6 attached to fuel injector housing 3
is fitted with a plunger 7 for fuel compression and distribution, and a cam disk 8 is fixed to one end of the plunger 7, and the cam disk 8 is connected to the drive shaft in the rotational direction via a driving disk (not shown). It is connected to. The cam disk 8 is formed with a cam surface 8' having ridges corresponding to the number of cylinders of the engine, and the cam surface 8' is held by a roller holder 9 that is rotatably held concentrically with the plunger 7. It is pressed against the roller 10 by a plunger spring (not shown). Therefore, due to the rotation of the drive shaft, the cam disk 8 rotates at the same rotation speed as the drive shaft. The plunger 7 is rotated by the rotation of the cam disk 8, and reciprocated for suction and pressure distribution of fuel by the rolling guide between the cam surface 8' and the roller 10.

During the suction stroke in which the plunger 7 moves downward in FIG. 2, the fuel in the chamber 4 is sucked into the plunger chamber 13 through the suction passage 11 and one of the suction grooves 12 that coincide with the suction passage 11. Subsequently, when the plunger 7 moves upward in FIG.
From there, it is injected into the cylinder from an injection nozzle (not shown) provided in the corresponding cylinder, via a pressure feed path 17 and a check valve 16 provided for each cylinder.

A cut-off port 19 connected to the hole 14 is provided in the portion of the plunger 7 that protrudes outside the barrel 6, and a control sleeve 18 is slidably inserted into the cut-off port 19 by reciprocating the plunger 7. When the control sleeve 19 comes off the upper edge of the control sleeve 18 and opens into the chamber 4, the compressed high-pressure fuel in the plunger chamber 13 flows out from the cut-off port 19 into the chamber 4, and fuel injection ends.

The position of the control sleeve 18 is adjusted by a known governor mechanism 20, and the injection amount is controlled to increase or decrease.

On the other hand, a timer piston 22 is provided in the cylinder hole 21 formed by the fuel injection device housing 3.
The timer piston 22 is connected to the roller holder 9 by a lever 23, and the displacement of the timer piston 22 causes the roller holder 9 to move.
It is configured to rotate. A hydraulic chamber 24 is formed between the fuel injection device housing 3 and one end surface of the timer piston 22, and fuel pressure in the chamber 4 is introduced into the hydraulic chamber 24 through a through hole 25 provided in the timer piston 22. A spring chamber 26 is formed at the other end of the timer piston 22 facing the hydraulic chamber 24, and a timer spring 27 is mounted in the spring chamber 26. Therefore, the position of the timer piston 22 responds to the fuel pressure in the hydraulic chamber 24, that is, the chamber 4, and the rotation direction and rotation stop position of the roller holder 9 are controlled via the lever 23 in accordance with the position of the timer piston 22. It will be decided.

Now, when the engine speed increases, the fuel pressure in the chamber 4 increases. Due to the increase in fuel pressure, the pressure in the hydraulic chamber 24 increases, and the timer piston 2
2 moves upward in FIG. 3 against the timer spring 27, and the roller holder 9 is rotated counterclockwise in FIG. 3 via the lever 23. This direction of rotation is opposite to the direction of rotation of the plunger 7. For this reason, the plunger 7 shifts to the pressure feeding distribution stroke earlier than the predetermined timing, the fuel injection timing becomes earlier, and the injection timing is advanced.

Further, when the engine speed decreases, that is, the fuel pressure in the chamber 4 decreases, and the pressure in the hydraulic chamber 24 decreases, and the timer piston 22 is moved downward in FIG. 3 by the timer spring 27. , the roller holder 9 is rotated clockwise, the injection timing is delayed, and the advance amount is decreased.

Therefore, the characteristic between the engine speed N and the amount of advance angle is a straight line as shown in FIG. 1 above.

Here, in this embodiment, the roller holder 9
A notch 28 is provided in the. On the other hand, a rotation shaft 29 rotatably supported by the fuel injection device housing 3
A lever 30 is fixed to the other end of the lever 30, and a pin 31 is fixed to the other end of the lever 30 so as to be positioned within the notch 28. A lever 32 is attached to the end of the rotating shaft 29 outside the fuel injection device housing, and the output shaft of an electromagnetic drive device 33 is connected to the lever 32. When the electromagnetic drive device 33 is energized, the pin 30 is moved to the lever 32. and 30 in the notch 28 of the roller holder 9
It is configured so that its position changes within the space. On the other hand, springs 34 whose tips are respectively engaged with the lever 32 and the fuel injection device housing 3 are mounted so as to oppose the movement of the pin 31 in the advancing direction.

When the electromagnetic drive device 33 is energized now, its output shaft moves in the direction of arrow B. This movement causes the pin 31 to move into the third position within the notch 28 of the roller holder 9.
It moves to a predetermined position indicated by a broken line in the figure, for example, a position corresponding to the rotational speed _N1 . In this state, as the engine speed increases as described above, the roller holder 9 rotates in the advancing direction. When the engine speed reaches N ₁ , the end surface of the notch 28 of the roller holder 9 comes into contact with the pin 31 . On the other hand, the power supply to the electromagnetic drive device 33 is cut off by a signal indicating that the engine speed exceeds _N1 by an engine speed detection device (not shown).
As the engine speed N further increases, the roller holder 9 moves in the advance direction against the spring 34. Therefore, from the time when the rotational speed _N1 is exceeded, it becomes equivalent to the force of the spring 34 being added to the force of the timer spring 27, and the moving speed of the timer piston 24, that is, the rotational speed of the roller holder 9 and the engine rotational speed N. The relationship between
Unlike the case up to N ₁ , the advance angle characteristic becomes a broken line characteristic as shown by the solid line in FIG.

The same applies when the engine speed decreases from a value higher than the rotation speed _N1 , and when the engine speed N exceeds the rotation speed _N1 , the timer spring 27 and the spring 34 act. The electromagnetic drive device 33 is excited when the engine rotational speed becomes less than or equal to the rotational speed _N1 . At this point, the movement of the pin 31 is stopped, and the roller holder 9 changes the injection timing by the force of the timer spring 27, resulting in the advance angle characteristic shown by the solid line in FIG.

Further, depending on the spring constant of the spring 34, it is possible to obtain advance angle characteristics as shown by the dashed line or broken line in FIG. Furthermore, by setting the positions of the lever 32 and the electromagnetic drive device 33, the position of the pin 31 during excitation of the electromagnetic drive device 33 can be changed, and the inflection point P in the advance angle characteristic shown in FIG. can change its position. Also, depending on the set pressure of the spring 34, at the set engine speed as shown by the two-dot chain line in FIG. It is also possible to obtain such characteristics as

Further, the electromagnetic drive device 33 may be energized and controlled according to a signal related to the engine load or the like. For example, the depression position of an accelerator pedal (not shown) or the position of the control sleeve 18 may be detected as a control signal as a signal related to the load.

Further, the electromagnetic drive device 33 may be energized and controlled by remote manual operation.

Further, in the above description, the driving device is an electromagnetic driving device, but the same applies even if a vacuum cylinder is used instead of the electromagnetic driving device. When using a vacuum cylinder, the vacuum pump line is connected to the vacuum cylinder to resist the spring 34 under engine operating conditions, for example, when the engine speed is up to N ₁ , and when the engine speed exceeds N ₁ , the vacuum pump line is connected to the vacuum cylinder to resist the spring 34. By switching the line to stop introducing vacuum to the vacuum cylinder and allowing the piston to move freely, it can be operated in the same manner as the electromagnetic drive device described above.

As described above, according to the present invention, the advance characteristic of the fuel injection timing adjustment device can be set in a polygonal manner.

[Brief explanation of the drawing]

FIG. 1 is an advance angle characteristic diagram of a conventional fuel injection timing adjustment device of a distributed fuel injection device. FIG. 2 is a partial sectional view showing an embodiment of a distributed fuel injection device to which the present invention is applied. FIG. 3 is a sectional view taken along the line AA in FIG. 2. FIG. 4 is an advance angle characteristic diagram for explaining the operation of the present invention. 2... Fuel supply pump, 3... Fuel injector housing, 4... Chamber, 7... Plunger,
8... Cam disk, 8'... Cam surface, 9... Roller holder, 10... Roller, 22... Timer piston, 23... Lever, 28... Notch,
29...Rotation axis, 30 and 32...Lever, 3
1...pin, 33...electromagnetic drive device, 34...spring.

Claims (1)

[Scope of utility model registration request] In a fuel injection timing adjustment device for a distributed fuel injection device, the fuel injection timing is controlled by driving an injection timing control member using a timer piston that responds to oil pressure that changes in relation to engine speed.
a drive device driven by the operating state of the engine;
an engaging member that is connected to the output shaft of the drive device via a connecting member and that selectively engages with the injection timing control member that is controlling the injection timing; and a movement that is applied to the engaging member in an advance direction. A distributed fuel injection device comprising a spring that resists the force, and wherein the driving device engages the engaging member with the injection timing control member according to the engine operating state to change injection timing characteristics. fuel injection timing adjustment device.