JPH0212291Y2 - - Google Patents

Description

[Detailed description of the invention] This invention uses an electric actuator to obtain the force that displaces the control rack of the fuel injection pump in the direction of increasing the injection amount, and automatically controls the operating power of this electric actuator based on fluctuations in engine speed. This invention relates to a stopping device for a diesel engine equipped with an electronic governor configured to do so.

A conventional stopping device for a diesel engine with an electronic governor includes means for displacing the control rack to a no-injection position by its return spring by cutting off the operation of an electric actuator that operates and displaces the control rack in the direction of increase in volume. However, in order to quickly and reliably move the control rack to the no-injection position, it is necessary to make the return spring quite strong.
However, if such a return spring is strengthened, the force of movement in the direction of increasing the control rack increases,
For this reason, it is necessary to make the electric actuator stronger and to increase the strength of the members connected thereto, which leads to an increase in the size and cost of the entire device.

The object of this invention is to provide a device that can reliably and quickly stop the engine while reducing such conventional drawbacks.

Embodiments of the present invention will be described below based on the drawings.

Figure 1 shows a side view of a water-cooled three-cylinder horizontal diesel engine. In the figure, 1 is the engine case, 2 is a piston that moves horizontally in the front and back, 3 is a crankshaft, 4 is a cylinder head, 5 is a fuel injection pump, 6 is a camshaft for driving the pump, 7 is a fuel injection nozzle, 8 is an intake/exhaust valve, 9 is a camshaft for valve operation, 10 is an intake pipe, 11 is an exhaust pipe, and both camshafts 6 and 9 are Timing belt 12 on crankshaft 3
are driven synchronously through.

Control rack 1 of the fuel injection pump 5
3 is controlled by an electronic governor G, the detailed configuration of which is shown in FIGS. 2 to 4.

An opening in the upper wall of the case housing the fuel injection pump 5 is closed with a cover 14, and a vertical support shaft 15 rotatably supported on the boss portion of the cover 14 is engaged with a rack pin 16 at its lower end inside the case. A governor lever 17 and an operating lever 18 are fixed to the outer upper end of the case, respectively.

The control rack 13 increases the injection amount when displaced in the a direction, and decreases it when displaced in the b direction, and extends between an operating lever 18 outside the case and a spring receiver (not shown) provided on the cover 14. A spring 19 is tensioned to bias the governor lever 17 in the injection amount decreasing direction b. Further, a solenoid 20, which is an example of an electric actuator for control, is attached to the cover 14, and the end of an operating wire 21 extending from the actuator 20 is connected to the operating lever 18, so that the operation supplied to the actuator 20 is connected to the operating lever 18. As the electric power increases and the tension of the wire 21 increases, the governor lever 17 is swung against the return spring 19, so that the amount of fuel injection increases.

This actuator 20 is connected to a control circuit unit A shown in FIG. is connected. The engine rotation speed detector 23 employs an electromagnetic coil-type rotation sensor disposed opposite to the tooth tips of a ring gear 24 (for interlocking with a starter motor and for driving a generator) attached to the crankshaft 3.
A pulse signal induced with the rotation of the motor 4 is extracted at a frequency proportional to the rotation speed.

The detection signal (pulse) from the rotational speed detector 23 is waveform-shaped in the unit A and then converted into a voltage V1 by the F-V converter (frequency-voltage converter) 25 to set the rotational speed. The setting signal (voltage) V0 from the device 22 is input to a comparison calculation circuit 26 including P, I, and D (proportional, integral, and differential) elements. Here, when the deviation between the set rotation speed and the detected rotation speed is within the allowable range, an output proportional to the set rotation speed is output, and when the detected rotation speed is lower than the set rotation speed, the above output is the speed deviation amount. The output is corrected to increase accordingly, and conversely, when the detected rotational speed becomes higher than the set rotational speed, the output is corrected to decrease.

Further, this comparison calculation circuit 26 includes a circuit 27 that generates a reference sawtooth wave signal V3 having a relatively high constant frequency.
It is also connected to the comparison circuit 28. In this comparison circuit 28, the output becomes a high level H only when the side input V2 is greater than or equal to the side input V3, and in the opposite case, the output becomes a low level L. Therefore, as shown in FIG. Output V4 from circuit 28
is extracted as a rectangular pulse signal having the same period as the sawtooth signal V3, and as the side input V2 increases, the pulse width d of the pulse output V4 increases.

This pulse output V4 is then used as an actuation signal for the actuator 20 in the transistor actuation circuit 29.
The actuator 20 is actuated in pulses by inputting d, and as the pulse width d increases, the average actuator actuation power increases and the actuation tension of the wire 21 increases. That is, as the engine rotation speed decreases below the set rotation speed, the operating power of the actuator 20 is increased and the control rack 13 is displaced in the injection amount increasing direction a, engine speed increase control is performed, and conversely, the engine speed is increased by the set rotation speed. When this occurs, the actuator operating power is reduced and the control rack 13 is returned to the injection amount decreasing direction b by the return spring 19, so that engine deceleration control is performed.

The above is the basic configuration and operation of electronic governor G.
Further, the following auxiliary control means is added to this. In addition, the reference numeral 30 in FIG. 4 is a constant voltage generating circuit used as a power source for each circuit section in the unit A, and the reference numeral 31 is a starting switch thereof.

Engine overspeed prevention mechanism The F-V converter 25 of the engine speed detector 23 is connected to the comparison circuit 33 together with the overspeed setting device 32, and when the engine speed exceeds a preset rotation speed, the comparison calculation circuit 2
6 is absorbed by the comparator circuit 33 side, and the side input terminal voltage V2 of the comparator circuit 28 becomes a low level, preventing the generation of the actuator actuation signal V4 and cutting off the operation of the actuator 20, thereby controlling the control rack. 13 is rapidly moved in the injection amount decreasing direction b by a return spring 19 to prevent damage caused by over-speeding of the engine.

Upper Limit Regulation Mechanism for Fuel Injection Quantity and Quantity Increase Mechanism for Engine Start On the case wall Va facing the injection quantity increasing direction a of the control rack 13, there is a holder with a stopper 34 that comes into contact with the tip of the control rack 13 to prevent its movement. It is attached via 35. This stopper 34 is fitted into the tip of the holder 35 so as to be able to slide in and out, and its movement stroke L is regulated via an elongated hole 36 and a pin 37. Further, the stopper 34 is biased in the projecting direction by an internal spring 38 with an initial elastic force.

Also, in the control unit A, a comparison circuit 40 connected to the F-V converter 25 and the increase rotation speed setting device 39 is provided, and only when the detected rotation speed is lower than the speed preset by the setting device 39, , is configured to apply a voltage V5 equal to or greater than the reference sawtooth wave signal V3 to the side input line of the comparison circuit 28, thereby controlling the speed when starting the engine, that is, when the engine reaches the set rotational speed from a stopped state. While rising, the output V4 from the comparator circuit 28 is made a full pulse, and the actuator 20
is set to operate at maximum power.

Then, only when the actuator 20 is operated with this maximum power, the force applied to the control rack 13 in the injection amount increasing direction a causes the stopper 34 to move backward by a predetermined stroke L against the biasing spring 38. , the strength and initial elastic bias of the spring 38 are set. Note that this spring 38 preferably has a small spring constant.

Therefore, from the time the engine is started until it reaches the set rotational speed, the engine is operated with the maximum fuel injection amount increased by the easy stroke L compared to the maximum fuel injection amount during normal operation.
When the set rotational speed is reached, the signal V5 from the comparator circuit 40 is cut off, and the engine is operated under the normal upper limit regulation.
A stopping lever 41 is provided in the opposite direction to 8, and a stopping electric actuator (solenoid) 42 is attached to this lever 41 and separately to the cover 14.
are connected by a wire 43, and when the actuator 42 is energized, the governor lever 17 is swung in the injection amount decreasing direction b.

Further, as shown in FIG. 4, this actuator 42 is connected to an engine stop switch 47 via two comparison circuits 44, 45 and a transistor drive circuit 46.
When the switch 47 is closed, the capacitor 48 connected to the side terminal of the first comparison circuit 44 is rapidly charged and the first comparison circuit 44
The output of the second comparison circuit 45 becomes high level, and accordingly, the output of the second comparison circuit 45 also becomes high level, and the actuator 42 is energized. Further, the output terminal of the first comparison circuit 44 is connected to the comparison circuit 3 for over-speed prevention.
When the output of the first comparator circuit 44 becomes high level, the output from the comparator circuit 26 is absorbed by the comparator circuit 33 side, and the voltage at the side input terminal of the comparator circuit 28 becomes V2. becomes a low level, and actuator 20 is deactivated as described above. Therefore, when the engine stop switch 47 is pressed, the operation of the control electric actuator 20 is cut off, and the now free governor lever 18 is forced back by the return spring 19 and the stop electric actuator 42, and the control rack 13 is placed in the no-injection position. It displaces it up to.

Also, when the switch 47 is opened, the capacitor 48
The charges charged in the first comparison circuit 44 are gradually discharged through the large value resistor 49, and the voltage V6 at the side input terminal of the first comparator circuit 44 gradually decreases as shown in FIG. Then, the charging voltage V6 is determined by the comparator circuit 44.
The voltage V given by the setting device 50 to the side input terminal
During the time T until the voltage drops below 7, the output V8 from the comparator circuit 44 remains at a high level H, and the control electric actuator 20 is shut off and the stop electric actuator 42 is continuously operated, and detection is stopped during this time. .

As explained above, this invention stops the operation of the control electric actuator for controlling the displacement of the control rack in the direction of increasing the injection amount and displaces the control rack to the no-injection position by operating the engine stop switch. Since the structure is configured such that energization of another stop electric actuator is performed at the same time, the engine can be stopped quickly and reliably with a simple switch operation. In addition, since the control rack is moved to the no-injection position by the actuation force of the stop electric actuator, there is no need to make the return spring of the control rack strong. , a relatively small output is required to exert an operating force commensurate with the strength of the return spring, and therefore the strength of the linking member between the control electric actuator and the control rack does not need to be very large. Although it is equipped with two actuators, the entire device can be made compact and inexpensive.

In addition, in this invention, the control rack of the fuel injection pump, which has a no-injection area at the end in the direction of decreasing injection amount, is returned to the direction of decreasing injection amount and is energized by a spring, so there is no possibility of electrical system failure or battery loss. Even if the stop electric actuator is no longer energized (the engine cannot be stopped by the stop electric actuator), the return spring acts to reduce the detected rotation speed, preventing the engine from running out of control. It is a structure that can be prevented and has a safe design.

[Brief explanation of drawings]

Figure 1 is a partially cutaway side view of the engine, Figure 2 is a perspective view of the electronic governor, Figure 3 is a longitudinal sectional front view of the fuel restriction device, Figure 4 is a control circuit diagram, and Figures 5 and 6. The figure is a time chart of control signals. 5...Fuel injection pump, 13...Control rack, 19...Return spring, 20...Electric actuator for control, 22...Engine rotation speed setting device, 23...Engine rotation speed detector, 42...
Electric stop actuator, 47...switch.

Claims (1)

[Claims for Utility Model Registration] 1. The control rack 13 of the fuel injection pump 5, which has a non-injection area at the end in the direction of decreasing the injection amount, is returned to the direction of decreasing the injection amount and is biased by the spring 19, and the control electric actuator 20 is It is configured to be displaced in the direction of increasing the injection amount by operating force, and the operating power to the control electric actuator 20 is controlled according to the deviation between the output from the engine rotation speed setting device 22 and the output from the engine rotation speed detector 23. A stop electric actuator 42 for displacing the control rack 13 to the no-injection position and an engine stop switch 47 for starting this are provided, and when the switch 47 is operated, the control electric actuator 20 A stopping device for a diesel engine with an electronic governor, characterized in that a control circuit is provided to cut off the operation of the diesel engine. 2. Scope of the Utility Model Registration Claim: The control circuit that cuts off the operation of the control electric actuator 20 incorporates a delay circuit to maintain the operation cutoff function for a certain period of time after the engine stop switch 47 is released. A stopping device for a diesel engine with an electronic governor as described in item 1.