JP2864972B2 - Fuel injection control device for diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a fuel injection control device for a diesel engine.

[0002]

2. Description of the Related Art As a conventional fuel injection control device for a diesel engine, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-225758, an electronic control system for automatically adjusting the engine speed in response to a load change. Some have governors.

In a fuel injection control device for a diesel engine disclosed in Japanese Utility Model Laid-Open Publication No. 56-154537, when an abnormality is detected, the movable lever collides with a stopper bolt via a pneumatic actuator to reduce the fuel. There have been proposals for forcibly reducing the supply.

[0004]

However, such a conventional fuel injection control device for a diesel engine has a structure in which a movable lever collides with a stopper bolt via an actuator when an abnormality is detected. There is a problem that the abrasion of the collision portion of the stopper bolt progresses, which causes a decrease in durability.

Further, if the operation speed of the actuator is reduced so as to reduce the impact at the time of collision between the movable lever and the stopper bolt, there is a problem that control responsiveness is insufficient.

An object of the present invention is to improve the durability of an electronically controlled governor by focusing on the above problems.

[0007]

According to the present invention, there is provided a rotary solenoid for adjusting a fuel injection amount according to its rotational position,
A return spring that urges the rotary solenoid in the rotation direction in which the fuel injection amount decreases, locking means that regulates the rotation range of the rotary solenoid that rotates by the urging force of the return spring, and energizes the rotary solenoid according to operating conditions A fuel injection control device for a diesel engine, comprising: a control means for adjusting a fuel injection amount by means of a motor; and a fuel cut switch for reducing a fuel injection amount by opening a circuit for energizing the rotary solenoid when an abnormality is detected. And a dropping resistor interposed in parallel with the fuel cut switch.

[0008]

According to the above arrangement, when the rotary solenoid is energized via the control means, the engine speed is automatically adjusted according to the load fluctuation.

When a circuit for energizing the rotary solenoid through the fuel cut switch when an abnormality is detected is opened, the rotary solenoid rotates in a direction to reduce the fuel injection amount by the urging force of the return spring, thereby forcing the engine speed. Is lowered.

Even if the fuel cut switch is opened when the abnormality is detected, the energization of the rotary solenoid is not completely stopped via the dropping register, but the excitation generated in the rotary solenoid by the current supplied through the dropping register. By stopping the rotation of the rotary solenoid at a predetermined position against the urging force of the return spring, the rotation range of the rotary solenoid is not restricted by the locking means, and the rotation of the rotary solenoid is controlled by the locking means. It is possible to prevent the member to be stopped from being worn. Further, it is possible to avoid a decrease in the responsiveness of the rotary solenoid.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the distribution type fuel injection pump provided in the diesel engine draws fuel by a feed pump 3 driven by a drive shaft 2, and supplies fuel to the pump chamber 5 from the feed pump 3. Through the suction port 6 and the high pressure plunger pump 7
Sent to

The plunger 8 of the plunger pump 7 is rotationally driven by the drive shaft 2 via the joint 2A in synchronization with engine rotation. The cam disk 9 fixed to the plunger 8 has the same number of face cams 10 as the number of cylinders of the engine. Each time the cam disk 9 rotates and passes over the roller 12 disposed on the roller ring 11, the plunger 8
Is reciprocated by a predetermined cam lift. By the reciprocating movement of the plunger 8, the fuel sucked from the suction port 6 is pressure-fed from the distribution port 13 to the injection nozzle (not shown) through the delivery valve 14.

In the process of moving the plunger 8 to the right in the drawing to pump the fuel from the plunger high-pressure chamber 7A to the distribution port 13, if the opening of the cutoff port 15 exceeds the right end of the control sleeve 16 in the drawing. The pumped fuel is released to the low pressure pump chamber 5. The fuel injection amount is
It is determined by the position of the control sleeve 16 that opens and closes the cutoff port 15 formed in the plunger 8. That is, when the control sleeve 16 is displaced rightward in the drawing, the fuel injection timing is delayed and the fuel injection amount is increased, and when the control sleeve 16 is displaced leftward in the drawing, the fuel injection timing is advanced and the fuel injection amount is reduced.

As shown in FIG. 2, as an electronically controlled governor for automatically adjusting the position of the control sleeve 16, the control sleeve 16 is provided with a rotary solenoid 2.
The first rotor 22 is engaged with a ball 23 eccentrically provided at the tip of the rotor 22. 3, the rotational movement of the rotor 22 is converted to a linear movement of the control sleeve 16.

As shown in FIG. 4, a rotary shaft 2 of a rotary solenoid 21 which rotates integrally with the roller 12 is provided.
0 is urged by two return springs 41 in a direction to reduce the fuel injection amount.
The fuel injection amount is increased by rotating the roller 12 against the return spring 41 by the exciting force generated at the time.

A movable plate 42 is connected to the rotary shaft 20 as locking means for restricting the rotation range of the rotary solenoid 21. When the movable plate 42 abuts against the stopper bolt 43 by the urging force of the return spring 41, the rotation range of the rotary solenoid 21 is regulated.

The fuel injection timing is controlled by the timer piston 25 via the roller ring 11 through the face cam 10.
Is adjusted by rotating the roller relative to the roller 12.

A control unit 35 provided as control means for the rotary solenoid 21 receives signals from an accelerator opening sensor 36, a suction pressure sensor 37, an engine water temperature sensor 38, an engine speed sensor 39, etc. And the no-load injection amount Qi determined from the engine water temperature and the basic value as the basic value.
Control.

When the abnormality of the engine is detected, the circuit for energizing the rotary solenoid 21 is used as a normally closed fuel cut switch as a normally closed fuel cut switch to reduce the fuel supply amount and reduce the engine speed to the idle speed. 4
5, a pump pressure switch 47 and an idle switch 48 are interposed in a circuit for energizing a coil 46 for opening a fuel cut relay 45. Note that other switch means may be used instead of the fuel cut relay 45.

The pump pressure switch 47 is turned on when the fuel pressure supplied from the feed pump 3 to the pump chamber 5 rises above a predetermined value.

The idle switch 48 is turned on in conjunction with the depression of the accelerator pedal becoming zero.

When the pump pressure switch 47 and the idle switch 48 are both turned on, the coil 46
Is energized, the fuel cut relay 45 is opened, the energization of the rotary solenoid 21 is stopped, and the roller 12 rotates in a direction to reduce the fuel injection amount by the urging force of the return spring 41.

As means for detecting abnormality of the engine, when the position of the control sleeve 16 is detected and the deviation between the actual injection amount and the target injection amount becomes a predetermined value or more, the coil 46 is energized and the fuel cut relay 45 is opened. You may make it.

When the energization of the rotary solenoid 21 is completely stopped, the movable plate 42 vigorously collides with the stopper bolt 43 by the urging force of the return spring 41, so that abrasion occurs at the collision portion between the two, and the durability is improved. Etc. may be reduced.

As a measure against this, the rotary solenoid 21
A dropping register 49 is interposed in parallel with the normally-closed fuel cut relay 45 in a circuit for energizing. The dropping register 49 has a predetermined resistance value and supplies a weak current to the rotary solenoid 21 even when the fuel cut relay 45 is turned off.

The configuration is as described above. Next, the operation will be described.

When the pump pressure switch 47 and the idle switch 48 are both turned on and the rotational speed is abnormally increased, even if the fuel cut relay 45 is opened, the dropping register 4
9, the energization of the rotary solenoid 21 is not completely stopped, and the exciting force generated in the rotary solenoid 21 by the current supplied through the dropping register 49 opposes the biasing force of the return spring 41. By stopping the rotation of the motor 21 at a predetermined position, the movable plate 42 does not come into contact with the stopper bolt 43, so that it is possible to prevent the abrasion of the collision portion between the two.

[0029]

As described above, the present invention provides a rotary solenoid for adjusting the fuel injection amount, a return spring for urging the rotary solenoid in a rotational direction in which the fuel injection amount decreases, and a rotation by the urging force of the return spring. Locking means for regulating the rotation range of the rotary solenoid, control means for adjusting the amount of fuel injection by energizing the rotary solenoid in accordance with operating conditions, and opening a circuit for energizing the rotary solenoid when an abnormality is detected. In a fuel injection control device for a diesel engine having a fuel cut switch for reducing the amount, a circuit for energizing the rotary solenoid is provided with a dropping resistor interposed in parallel with the fuel cut switch. Supply via a dropping register even if the switch is opened To stop the rotation of the rotary solenoid in place excitation force generated in the rotary solenoid by current is against the biasing force of the return spring,
Wear and the like are prevented from occurring in the member for locking the rotation of the rotary solenoid in the locking means, and the durability can be improved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view of the rotary solenoid.

FIG. 3 is a view showing a positional relationship between a rotary shaft of a rotary solenoid and a control sleeve.

FIG. 4 is a plan view showing a movable plate and a stopper bolt of the rotary solenoid.

[Explanation of symbols]

 Reference Signs List 21 rotary solenoid 35 control unit 36 accelerator opening sensor 37 suction pressure sensor 38 engine water temperature sensor 39 engine speed sensor 41 return spring 42 movable lever 43 stopper bolt 45 fuel cut relay 47 pressure switch 48 idle switch 49 dropping register

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ identification code FI F02M 59/44 F02M 59/44 H (58) Field surveyed (Int.Cl. ⁶ , DB name) F02D 41/20 375 F02D 1 / 00-1/18

Claims (1)

(57) [Claims] A rotary solenoid for adjusting a fuel injection amount in accordance with the rotational position; a return spring for urging the rotary solenoid in a rotational direction in which the fuel injection amount decreases; a rotary solenoid for rotating by the urging force of the return spring; Locking means for regulating the rotation range of the motor, control means for adjusting the fuel injection amount by energizing the rotary solenoid according to the operating conditions, and reducing the fuel injection amount by opening a circuit for energizing the rotary solenoid when an abnormality is detected A fuel injection control device for a diesel engine, comprising: a fuel cut switch to be turned on; and a dropping register interposed in parallel with the fuel cut switch in a circuit for energizing a rotary solenoid.