JPS58133451A - Engine controller - Google Patents

Abstract

PURPOSE:To obtain the effect of energy saving or favorable workability corresponding to the working condition in such a way that resistance in the duct of a hydraulic device can be selected and changed over at the time of transferring the engine from its high speed revolution to its low speed revolution. CONSTITUTION:When a change-over valve 20 is manually changed over to a position 1, the pressurized oil in a pump 8 actuates a change-over valve 7 and arrives at the change-over valve 20 upon control of a lever 9. Since duct resistance for a throttle valve 23 is large, the pressurized oil is quickly fed to a cylinder 12, a piston 13 is moved to the right, and the engine 1 makes its high speed revolution. When the lever 9 is returned to its neutral position, the piston 13 is moved to the left, and the revolution speed of the engine 1 is lowered, or the pressurized oil can not be quickly returned to a tank 5, and the descent time is made longer. Besides, when the valve 20 is changed over to the position II, and a control lever 9 is returned to its neutral position, the pressurized oil on the rod side of the cylinder 12 is returned to the tank 5 the piston 13 is also quickly moved to the left, the injecting rate is reduced at once, and the descent time is made shorter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine control device, and more particularly to an engine control device suitable for controlling a tank that drives a hydraulic engine of a working machine.

A working machine such as a hydraulic pump is equipped with a hydraulic pump that supplies pressure oil to an actuator, and this hydraulic pump is driven by an engine mounted on the working machine. The rotational speed of this engine is controlled by a control lever.

A conventional example of such an engine control device is shown in FIG.

In the figure, 1 is an engine, 2 is a fuel injection mechanism provided with the engine IK4Is, and 3 is a fuel injection amount control lever of the fuel injection mechanism. The control lever 8 is rotatably provided around an axis C. When the control lever 8 is rotated clockwise, the amount of fuel injected from the fuel injection mechanism 8 is reduced to make the engine 1 sluggish, and when the control lever 8 is rotated counterclockwise, the fuel injection The injection amount is increased to make the engine 1 rotate at a high speed.

Reference numeral 4 designates a Sanno pump which is operated by an engine llcJItAm, and supplies oil stored in a tank 5 to the hydraulic circuit as pressure oil. 6 is an actuator driven by the pressure oil of the hydraulic pump 4, and in the figure (a circular pressure cylinder is shown). Controls the operating direction of the actuator 6 and the amount of pressure oil supplied to the actuator 6.

8 is a pilot hydraulic pump for supplying pressure oil to operate the directional control valve 7; 9 is an operating lever provided on the driver's seat; the pilot hydraulic pump 8 is activated depending on the operating direction and operating amount of the operating lever 9; Pressure oil is supplied to the directional control valve 7 to operate it.

10a and lOb are pilot switching valves that are switched according to the amount of operation of the operating lever 9. When the operating lever 9 is pushed to the left in the figure, the pilot switching valve 10a is switched, and when it is pushed to the right, the pilot switching valve 10b is switched, and the operating lever is switched. When 9 is in the neutral position, it communicates with tank 5. 11 is a shuttle valve that allows the pressure oil from the pilot hydraulic pump 8 to pass through the pilot switching valves 10a and 1Ob.

12 is a control cylinder. The control cylinder 12 includes a piston 18, a piston rod 14. It consists of a spring 15 that pushes the piston 1B toward the rod 14 side. The rod 1411111 of the control cylinder 12 is connected to the shuttle valve 11. Reference numeral 16 is a connecting rod that rotatably connects the end of the control lever 8 and the end of the rod 14.

Shuttle valve 11. The control cylinder 12, the connecting rod 16, the control lever 8, and the fuel injection mechanism 2 constitute an engine control device.

Note that 17 and 18 are relief valves that set the maximum pressure of the hydraulic pump 4 and the pilot hydraulic pump 8, respectively.

Next, the operation of this engine control device will be explained.

When the operating lever 9 is tilted to the left or right in the figure, the pressure oil from the pilot hydraulic pump 8 flows through the pilot switching valve 10a or lOb, and the pressure causes the directional switching valve 7 to shift to the right in the figure according to the amount of operation of the operating lever 9. The pressure oil from the hydraulic pump 4 is supplied to the head side or the rod side of the actuator 6, and the oil from the rod side or head side is returned to the tank 5.

Thereby, the actuator 6 operates according to the amount of operation of the operating lever 9.

At the same time, the pressure oil that has passed through the pilot switching valve 10a or 10b is supplied to the rod side of the control cylinder 12 via the shuttle valve 11. Note that at this time, the shuttle valve 11 cuts off the circuit that passes through the pilot switching valve 10b or 10a and leads to the tank 5. As a result, the piston 18 moves to the right against the spring force of the spring 15. therefore,
The rod 14 and the connecting rod 16 also move to the right, and the control lever 8 rotates counterclockwise around the axis C to increase the fuel injection amount, rotate the engine at high speed, and increase the discharge amount of the hydraulic pump command. increase

When the operating lever 9 is returned to the neutral position, the pilot switching valve 10
a or 1 (Jb returns to its original position, pilot A hydraulic pump 8
While blocking the passage of pressure oil from the control cylinder 12
The oil on the rod side is returned to the tank 5 via the shuttle valve 11. For this reason, piston 1B &! It moves to the left by the spring force of the spring 15. Therefore, the rod 14 and the connecting rod 16 are also moved to the left to move the control lever 8 to the axis C.
It rotates clockwise around , decreases the fuel injection amount, and lowers the rotational speed of the engine l.

In such an engine control device, the operating lever 9
By returning the engine to the neutral position, the fuel injection amount is automatically reduced and the engine speed is reduced, so unnecessary fuel consumption can be suppressed and an energy saving effect can be obtained. This energy-saving effect is greater as the transition time from high-speed rotation to low-speed rotation (hereinafter referred to as descent time) of the engine 1 is faster.

On the other hand, the time it takes for the engine 1 to shift from low speed rotation to high speed rotation (hereinafter referred to as return time) is quite long when the load is large. That is, when the operating lever 9 is operated from the neutral position, the engine returns to high speed rotation in a short time if the load is light, but it takes a long time to return to high speed if the load is large. Therefore, during this long return time, the amount of pressure oil discharged from the hydraulic pump 4 is not sufficient, which adversely affects work efficiency. Sometimes,
In operations where the operating lever 9 is frequently cut from the neutral position to the operating position, its influence is large.

In order to eliminate this negative effect and improve workability, the lowering time of the engine 1 may be lengthened so that switching of the operating lever 9 from the neutral position to the operating position takes K during the lowering time. That is, by doing this, if the operating lever 9 is frequently switched, if the operating lever 9 is placed in the neutral position and switched to the operating position at regular intervals, the engine l has not yet reached low speed rotation. , the time to return to high speed rotation is extremely short.

However, in operations where it takes a long time to switch the operating lever 9 to the next operating position after returning it to the neutral position, it is desirable to shorten the lowering time from the viewpoint of energy saving effect, as described above.

In the end, there are contradictory demands: it is necessary to shorten the descent time in order to obtain an energy-saving effect, but it is necessary to lengthen the descent time in order to obtain good workability, and there are drawbacks to either option. It is inevitable that this will occur.

An object of the present invention is to provide an engine control device that can satisfy both energy saving effects and good workability.

To achieve this object, the present invention provides an engine connected to a hydraulic pump, a fuel injection of the engine, an operating device for operating an actuator connected to the oil pump, and an operating device connected to the hydraulic device for operating the actuator. In an engine control device equipped with a conduit that guides pressure oil according to the operation of the device,
A feature of the present invention is that the resistance of the conduit can be selectively changed when the engine is moved from high speed to low speed.

Hereinafter, the invention will be explained based on an embodiment shown in FIG.

In this embodiment, the same parts as those in the conventional example shown in FIG. 1 are given the same reference numerals, and their explanation will be omitted. 2° is a switching valve that can be manually switched between two positions, and can be selectively switched between the first position (■) and the second position (■). 21a,
21bs and 21c are pipe lines having one end connected to the switching valve 20. Reference numeral 22 denotes a check valve interposed in the pipe line 21a, which allows pressure oil from the switching valve 2o to pass therethrough and blocks pressure oil from the control cylinder 12. Reference numeral 28 denotes a throttle provided in the pipe line 21b, and the resistance of the pipe line against the pressure oil passing through this throttle increases. Note that the conduit 21C is not provided with a restriction, and the conduit resistance to the pressure oil passing through the conduit 21C is extremely small. Conduit 21a.

The other ends of 21b and 21C are both connected to the rod side of the control cylinder 12.

Next, the operation of this embodiment will be explained.

It is assumed that the switching valve 20 has been manually switched to position I. As mentioned above, when the operating lever 9 is operated, the pressure oil of the pilot hydraulic pump 8 is transferred to the pilot switching valve 1.
0a or 10b to operate the directional switching valve 7 and pass through the shuttle valve 11 to reach the switching valve 20. A check valve 22 and a throttle 28 are connected in parallel to the switching valve 20, but since the pipe resistance of the throttle 28 is large, the pressure oil suitable for the switching valve 20 is the check valve 22 in the pipe 21H. is rapidly supplied to the control cylinder 12 through the piston 18, and moves the piston 18 to the right. From this K, the amount of fuel injected from the fuel injection mechanism 2 increases, and the engine 1 rotates at a high speed.

When the operating lever 9 is returned to the neutral position, the pilot switching valve 1
Both 0a and 1Ob are in communication with the tank 5.

The piston 1B of the control cylinder 1z moves to the left by the spring force of the spring 1z, discharging the pressure oil on the rod side, and reducing the fuel injection amount to make the engine 1 rotate at a low speed. At this time, the pressure oil discharged from the rod side of the control cylinder 12 cannot pass through the check valve 22, so the pipe line 21
Going back through the throttle 28 of b, the shuttle valve 11. It returns to the tank 5 via the pilot switching valve 9. In this case, the pressure oil from the control cylinder 12 cannot quickly return to the tank 5 because the pipe resistance due to the throttle 28 is large, and as a result, the return of the screw 718 of the control cylinder 12 becomes slow. Therefore, it takes time to reduce the amount of fuel injected by the fuel injection mechanism 2, and the descent time becomes longer.

When the switching valve 20 is manually switched to position (2), only the pipe ZIC is connected to the switching valve 20. Therefore, in this case, the condition is the same as that of the conventional example shown in FIG. The fuel injection amount is immediately reduced by moving to the left, and the descent time is shortened.

In this way, by switching the switching valve 20 to position I, a long descending time can be obtained, and by switching the switching valve 20 to position II, a short descending time can be obtained.

Note that in this embodiment, the switching valve 20 is switched to two positions so that two falling times can be selected, but it is also possible to prepare pipes with different degrees of restriction and use switching valves accordingly. Accordingly, eight or more descent times can be selected and used.

As described above, in the present invention, it is possible to select and switch the line resistance of the hydraulic system line when the engine shifts from high-speed rotation to low-speed rotation, so energy can be saved depending on the working condition. effect or good workability can be obtained.

[Brief explanation of drawings]

Figure g1 is a system diagram of the hydraulic circuit of a conventional engine control device.
FIG. 2 is a system diagram of a hydraulic circuit of an engine control device according to an embodiment/example of the present invention. l...Engine, 2...Fuel injection mechanism, 8...Actuator, 9...Control lever, lOa, 10b... Pilot switching valve, 11... Curved shuttle valve, 1z... Control cylinder, 18... Piston, ■4... Lot, 15... Spring, 16... ...Connecting pipe, 20...Switching valve, 21a, 21b121
c...Curved pipe line, 22-knee check valve, 2B...
・Aperture. Sai1kan';i2 figure

Claims (1)

[Claims] An engine connected to an oil pump, a fuel injection mechanism for this engine, and a hydraulic system that controls this fuel injection mechanism;
An engine control device comprising: an operating device for operating an actuator connected to the hydraulic pump; and a path connected to the hydraulic device to guide pressure oil in response to operation of the operating device, the engine control device operating the engine at high speed. An engine control device characterized by providing a means for selectively switching the resistance of the pipe when the rotation is shifted from rotation to low speed rotation.