JPH0599096A - Operating cam mechanism for unit injector - Google Patents

Abstract

PURPOSE:To perform optimum control on oil feeding rate in response to engine operating conditions by controlling a slide stand based on output signals from a detection means detecting engine operating conditions, and thereby changing the actuation point of an auxiliary cam arranged for a cam follower. CONSTITUTION:When a cam follower 10a is rocked around a pin 13 by rotating a main cam 21 which is interlocked with engine operations, an auxiliary cam 22 is rocked around a pin 23 so that the vertical movement of a push rod 34 allows an unit injector 30 to be driven via a locker arm 32. In this case, total cam lift (main cam plus auxiliary cam) can be made variable with the auxiliary cam 22 followed to the main cam 21 in response to the position of a slide stand 26, so that the auxiliary cam 22 is rotationally displaced in response to the displacement of the slide stand 26 slidably moved by an actuator 40 via a link 24. The actuator 40 is drivingly controlled by a controller 41 inputting accerator signals 42, revolution signals 43 and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating cam mechanism for a unit injector.

[0002]

2. Description of the Related Art A cam device for a unit injector is shown in FIG.
As described above, the roller 14 is attached by the pin 12 to the lower end of the cam follower 10 supported by the pin 11 and the pin receiver 20, and is in contact with the cam 21. The push rod 34 abuts on the upper end, and the unit injector 30 can be driven via the adjusting screw 33, the rocker arm 32, and the spring 31. When the cam 21 rotates as shown, the cam follower 10 swings around the pin 11 as a fulcrum, and the push rod 34 moves up and down to drive the unit injector 30 to inject fuel into a combustion chamber (not shown).

[0003]

However, in such a conventional unit injector cam device,
Once the shape of valve operating parts such as the cam surface shape was determined, it could not be changed even if the operating conditions changed, and therefore fuel could be injected only at the same oil feed rate. The present invention has a simple configuration and is intended to make the oil feed rate of the unit injector variable according to the operating condition of the engine.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and a main cam disposed on a cam shaft, and a cam follower, tappet, and push rod that abut on and interlock with the main cam. In the operating mechanism of the rocker arm and the unit injector that abuts on one end of the rocker arm and moves up and down, a rotatable roller is arranged at the abutting portion of the main cam of the cam follower supported by the pin on the cylinder block. Furthermore, a sub cam that is swingably supported is disposed at the contact portion of the cam follower with the tappet, and a link that is swingably supported by a pin is connected to the top of the sub cam. A slide base connected by a pin is arranged at the other end of the other side, and further, a detection means for detecting the operating condition of the engine on the slide base and the slide base by the signal of the detection means. A configuration to dispose a control means for adjusting slidably.

[0005]

With the above structure, the operating point of the auxiliary cam arranged on the cam follower is changed by the detecting means for detecting the operating condition of the engine and the control means for controlling the slide base by the signal, thereby changing the lift amount of the abutting tappet. By making it variable, the plunger stroke of the unit injector can also be made variable to change the oil feed rate.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the embodiment shown in the configuration diagram of FIG. 1 and the total cam lift velocity diagram of FIG. 3 that are the same as those in the conventional example shown in FIG. In FIG. 1, a sub cam 22 abutting against a tappet 35 is swingably mounted by a pin 13 on the top of the cam follower 10a, and a roller 14 abutting on the main cam 21 is freely mounted by a pin 12 on the top of the lower end. Has been done. The top of the other end is supported by the pin 11 and the pin receiver 20. The link 24 is swingably connected to the top of the sub cam 22 and the slide base 26 by pins 23 and 25.
The slide base 26 can be moved by the actuator 40 controlled by the controller 41. When the cam 21 rotates as shown, the cam follower 1
0a swings about the pin 11 as a fulcrum, and the sub cam 22 swings about the pin 23 as a fulcrum. Therefore, the sub cam 22 follows the main cam 21 according to the position of the slide table 26, and the total cam lift (main cam + sub cam). Cam) can be variable.
In FIG. 1, the AA positions of the sub cam 22 and the link 24 are
When the oil feed rate is the same as in the conventional case, when the cam lift of the main cam 21 is 0, the position of the slide base 26 is set so that the tappet 35 is on the base circle of the sub cam 22, and the sub cam rotates. However, as shown by the curve A in FIG. 2, the total cam lift speed is as shown in the lift speed diagram of the main cam. When it is desired to reduce the oil transfer rate at high speed and low load, the tappet 35 is used when the cam lift of the main cam 21 is 0 as shown at the position BB in FIG.
The position of the slide base 26 is set so that it is halfway down the auxiliary cam 22. Therefore, as shown by the curve B in FIG. 2, when the main cam starts to lift, the sub cam descends by the link mechanism, and the total cam lift speed decreases. When the oil feed rate is increased to shorten the injection period such as under high load, the slide base 2 is arranged so that the tappet 35 is on the up side of the sub cam 22 when the cam lift of the main cam 21 is 0 as in the CC position of FIG.
Determine the position of 6. When the main cam starts to lift, the sub cam moves up by the link mechanism, so the initial total cam lift speed increases as shown by the C curve in FIG. Therefore, a high oil transfer rate can be obtained in the initial stage. In the above embodiment, the actuator 40 of the slide table 26 may be operated by fluid pressure (hydraulic pressure, pneumatic pressure) or mechanical operation. The input signal to the controller 41 is 42 accelerator signal, 43
A rotation speed signal or the like can be arbitrarily selected. The pilot injection can be controlled by appropriately changing the cam profile of the auxiliary cam 22. In the embodiment, tappet 35
However, the same part may be used as a roller tappet.

[0007]

As described above, the unit injector variable cam device of the present invention has a simple structure as described above, and is capable of controlling the optimum oil feeding rate according to the operating condition of the engine.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an operating mechanism of a unit injector of the present invention.

FIG. 2 shows a total cam lift velocity diagram of the present invention.

FIG. 3 is a configuration diagram showing an operation mechanism of a conventional unit injector.

[Explanation of symbols]

 10, 10a ・ ・ ・ Cam follower 21 ・ ・ ・ ・ ・ ・ Main cam 22 ・ ・ ・ ・ ・ ・ Sub cam 24 ・ ・ ・ ・ ・ ・ Link 26 ・ ・ ・ ・ ・ ・ Slide base 40 ・ ・ ・.... Actuator 41 ..... Controller

Claims (2)

[Claims] 1. A main cam disposed on a cam shaft, a cam follower, a tappet, a push rod, a rocker arm that abuts and interlocks with the main cam, and a unit injector that abuts on one end of the rocker arm and moves up and down. In the operating mechanism, a rotatable roller is arranged at the contact portion of the cam follower supported by the pin on the cylinder block with the main cam.
Furthermore, a sub cam that is swingably supported is disposed at the contact portion of the cam follower with the tappet, and a link that is swingably supported by a pin is connected to the top of the sub cam. An operating cam mechanism for a unit injector, wherein a slide base connected by a pin is arranged at the other end. 2. A unit injector characterized in that the slide base is provided with detection means for detecting an operating condition of an engine and control means for slidably adjusting the slide base according to a signal from the detection means. Operating cam mechanism.