JPS62191638A - Method for controlling engine with automatic deceleration device - Google Patents

Abstract

PURPOSE:To eliminate the waste of fuel while reduce noise by reducing engine speed with a curved rate of change from a set rotation condition at the time of operating to an idling engine speed, when the operating levers for all operating devices are set neutral. CONSTITUTION:When a fuel control lever 7 is set in a full position and an engine 1 is operated at full speed, direction selector valves 22a, 22b are controlled in their switchover in accordance with the operating conditions of the operating levers 20a, 20b of proportional control valves 19a, 19b, to operate various actuators 21. When an automatic deceleration switch 34 is set in on position while setting all operating levers 19a, 19b in a neutral position and, as the actuators 21 are stopped, each of detectors 23a, 23b are turned on and an electromagnetic selector valve 13 is shifted to a decelerating position 13a. Also, an electromagnetic proportional throttle valve 16 is equally controlled, and the engine speed is reduced to an idling condition with a curved rate of change.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an engine for a construction machine such as a power shovel,
In particular, the present invention relates to a 1ljl control method for an engine equipped with an auto-deceleration device.

Conventional technology Construction machines such as the Power 7 Yovel carry out work such as excavation and pouring with the engine running at full speed.
In between these tasks, there are downtimes such as waiting for dump trucks. During this downtime, it is desirable to idle the engine to prevent noise generation and to conserve fuel. However, it is troublesome for the operator to operate the secondary fuel leg lever to the idle position every time the work is stopped.

Therefore, an auto deceleration system is applied repeatedly to the engine's fuel control system, and when the work is stopped and all actuators are stopped, this is detected and the engine's fuel control system is activated so that the fuel control lever is at the full rotation position. It is designed to be in an idling state regardless of the situation.

In the conventional auto deceleration device for an engine equipped with an auto deceleration device, the auto deceleration device operates immediately when all of the operation levers of the work equipment are set to neutral and the work equipment is at rest, and the auto deceleration device operates to a predetermined position as shown by the solid line α in Fig. 8. Either the engine speed drops to idle speed within a certain period of time, or the deceleration operation starts after a certain period of time, for example about 10 seconds, as shown by the solid line in Figure 6. For example, Special Publication No. 60-38561).

1. Points to be solved by the invention In the former case, the engine speed decreases each time the work equipment is stopped and operated intermittently. The power that drives the hydraulic pump that supplies hydraulic oil causes a waving phenomenon, and the engine sound also causes a waving phenomenon. In addition, when the work equipment is stopped for a short time and the engine speed is reduced, the hydraulic pump's discharge 'Mk gradually increases, so the actuator speed changes to a value that corresponds to the amount of operation of the control lever. This does not occur immediately, and operability is significantly impaired.

On the other hand, in the latter of the above conventional examples, the engine continues to rotate at high speed for a predetermined period of time after all work equipment stops until it decelerates, so the above problem is eliminated, but it takes a particularly long time to operate the work equipment. In the case of intermittent work where there is a pause in the ftt+, fuel is wasted during this period and the noise is high. Also, during the fixed period of time before deceleration occurs, the operator cannot clearly grasp when the engine speed will drop, and the deceleration condition may suddenly occur, which can be surprising.

In addition, in both of the above conventional examples, the engine speed decreases at a constant rate from beginning to end during auto-deceleration, so the change in engine speed during high-speed rotation is large, and the engine and hydraulic equipment Impact force acts on the 4F, which has a negative impact on the lifespan of each
was giving.

Means and Action for Solving the Problems The present invention was conceived in view of the above-mentioned problems. At the same time, it is possible to reduce the engine speed even slightly to match the working conditions with the operator's feelings, and to avoid wasting fuel.
Another object of the present invention is to provide a complete control method for an engine equipped with an auto-deceleration device that can completely reduce noise and further reduce the impact force on the engine and hydraulic equipment at the initial stage of deceleration during auto-deceleration. When all the operating levers of the work equipment are in neutral, the engine speed decreases at a curved rate of change until it reaches the idle link state. Also, you can select this bending machine depending on the work situation.

Example An embodiment of the present invention will be described with reference to FIG.

In the figure, 1 is the engine, 2 is the governor, and 3 is the control lever that controls the governor 2. By moving the control lever 3 to the stop position, idle link position (deceleration position), or full position, the engine 1 is stopped. , idling rotation, full rotation. The control lever 3 is equipped with a loose spring *4, a link 5 and a rod 6'j&:
via which it is connected to a manual fuel control lever 7. A piston rod 1° of a deceleration cylinder 9 is connected to an intermediate portion of the control lever 3 via an elongated yoke 8. By supplying pressure oil to the bottom chamber 111C of the deceleration cylinder 9, the piston rod 10 is actuated against the spring 12 to operate the control lever 3 from the full position to the idle link position (deceleration position [1). It has become.

The bottom chamber 11 of the deceleration cylinder 9 has an electromagnetic switching valve 13.
It is connected to the secondary leg pump 14 and tank 15 via. An electromagnetic proportional throttle valve 16 is interposed between the bottom chamber 11 of the decel cylinder 9 and the electromagnetic switching valve 13.

The electromagnetic switching valve 13 has a "deceleration" position 13α and a "drain" position +3b, and is always in the "drain" position +
3b and solenoid 1
When power is applied to 7, the deceleration position is switched to 13α.

19α, 19b are proportional control valves (/'PC' valves), and these proportional @ potash valves 19α, 19b are the above mlJ
It is connected to the dual purpose pump 14, and each proportional control dual valve +9
By rotating the control levers 20α and 20h of cL and 19b, the directional control valve 22α installed in the hydraulic circuit of the 7-cut eater 21 for working machines such as boom cylinders, arm cylinders, packet cylinders, and swing motors can be operated.
, 22b are switched, and these directional control valves 22α, 22b are switched and controlled.

Each operating lever 20α, 20b of the proportional control valve +9cL, I9b is located near the operating lever 20α, 20b.
Detectors 23α and 23b, such as limit switches, which are turned on when α and 20b are in the neutral position are provided oppositely.

The detection range of each of these detectors 23α and 23h is the operating lever 2.
0α.

The operating levers 20α, 20b are not limited to the short range of the neutral position of the operating lever 20b, but when the operating levers 20α, 20b are rotated from the operating position to the neutral vermilion position, and the directional control valve 22 (L, 226 is substantially in the neutral position). It is designed to turn ON in the rotational position.

The tm proportional throttle valve 16 includes a check valve 24 and a variable throttle valve 25 that allow flow from the bottom chamber 11 direction of the deceleration cylinder 9.
The variable throttle valve 25 is connected in parallel with the variable throttle valve 25.
1 to 1! A magnetic proportional valve 26 is connected.

The variable throttle valve 25 of the electromagnetic proportional throttle valve 16 has a plurality of wedge-shaped throttle grooves 29 in the land 28 of the throttle spool 27 whose cross-sectional area is varied throughout in the axial force direction. is provided, and this aperture spool 27 full spring 3
By pushing in against o, the opening degree of the throttle gradually increases. A rod 32 connected to the electromagnetic proportional valve 26 is opposed to the throttle spool 27, and is biased in the pushing direction by the electromagnetic proportional valve 26 via the rod 32. Solenoid proportional valve 26
is designed to output an operating force corresponding to the applied power, and is connected to a control device ft33 such as a microcomputer. The control f111 device 33 is the detector 23
α, 23b, and the detector 23α.

A predetermined current is sent to the electromagnetic proportional valve 26 by inputting a signal just in case 23b turns ON.

Throttle spool 2 in the above 'gIL magnetic proportional throttle valve 16
7 and the change in the current from the control device 133, the flow rate of oil passing through the electromagnetic proportional throttle valve 16'ft after input signals from the detectors 23α and 23b are input to the control device 33 is shown in FIG. As shown, it changes by drawing a clear continuous curve that is convex or concave downward.

Reference numeral 34 denotes an auto-deceleration switch interposed between the detectors 23α, 23b and the control device 1133 of the electromagnetic switching valve 13, and the auto-deceleration switch 34 can select a change in engine speed. . For example, when the auto-deceleration switch 34 is operated, if the auto-deceleration switch 34 is convex downward, it is set to (■), and when it is concave downward, it is set to (5).
11), or when not operating the auto deceleration operation, set it to ■.

A control method according to the present invention using the above configuration will be described below.

The engine 1 of the construction machine is normally operated at full speed so as to exhibit its maximum capacity. That is, the fuel control lever 7 is set at the full position as shown by the solid line in FIG.

At this time, the movement of the control lever 3 of the governor 2 is not mechanically interfered with by the deceleration cylinder 9 because of the long hole in the long hole yoke g.

In this state, the operating levers 20 of the proportional control valves 19α and 19h
By operating α, 20b', the directional control valve 22α,
22b is switched and controlled, and pressure oil from the hydraulic bonders 36 and 37 driven by the engine 1 in the full rotation state is selectively supplied to the actuator 21 to operate the boom cylinder, arm cylinder, etc.

At this time, since the detectors 23α and 23b provided opposite to the operating levers 19α and 19h are OFF, even when the auto deceleration switch 34k is ON, the 'flL magnetic free valve 13 is not switched to the "drain" position Fj13AK. Therefore, the bottom chamber II of the deceleration cylinder 9 is drained through the check valve 24 and the "drain/" position ff13b'e of the electromagnetic switching valve) 3, and the piston rod 12 of the deceleration cylinder 11 is drained.
is in a shortened state.

Next, with the auto deceleration switch 34 set to ■ or ■, all operating levers 19α and 19bk are set to neutral to switch each direction -7f2, for example, to wait for a dump truck, etc.
When 2α, 22bk are set to neutral and the actuator 21 is stopped, the operating levers 19α, 19h return from the operating position to the neutral position, and the levers 23σ, 23b are turned on, thereby turning on the electromagnetic switching valve 13. 0, IV
Then, it switches to the "decel" position +3 cL.

At the same time, the detector 23' is also sent to the control device 33.
A signal is input from +23b. When a signal is input to the control device 33, the electromagnetic proportional valve 26 of the electromagnetic proportional throttle valve 16 is activated, the throttle spool 27 is pushed in the opening direction, and the control signal passes through the 1 decel position 13α of the electromagnetic switching valve 13. Pressure oil from the pump is supplied to the bottom chamber 11 of the deceleration cylinder 9 through the solenoid proportional valve 16, the piston rod 10 of the deceleration cylinder 9 is moved to extend, and the control lever 3, which was in the full position, is moved. The engine 1 is returned to the deceleration position, and the engine 1 enters an idling rotation state (FIG. 1).

At this time, the flow value of the pressure oil supplied to the bottom chamber 11 of the deceleration cylinder 9 is controlled by the electromagnetic proportional throttle valve 16 as shown in FIG. As shown in Figure 4, the rotation angle changes in a downwardly convex (or downwardly concave) smooth continuous curve, moving slowly at first and gradually becoming faster.

Therefore, due to the operation of this II7 lever 3, the engine speed, which was at full speed, changes as shown in Fig. 5, drawing a smooth continuous curve convex upward, decreasing slowly at first, and then gradually decreasing. The rate of decline increases.

In other words, the engine speed, which was at full speed, slowly decreases at first, and then greatly decreases to idle speed.

When the auto-deceleration switch 34 is set to 2aFF and 'fc, even if all the operating levers 20α and 20h become neutral and the engine load becomes lighter, the above-mentioned auto-deceleration effect is not performed.

In the above operation, the detectors 23α, 23b are turned ON when the operating levers 20α, 20b are rotated from the operating position to the neutral direction and the directional control valves 22α, 22b are substantially neutral. The deceleration operation is done by engine 1.
This is done at the same time as the load is reduced, and it is possible to prevent an unnecessary increase in engine rotation speed when the load is reduced.

In the above embodiment, the throttle groove 29 is used as a means for changing the pressure of the pressure oil supplied to the bottom chamber 11 of the deceleration cylinder 9 into a smooth continuous curve that is convex downward (or concave downward) as shown in FIG. The aperture spool 27 (
An example has been shown in which the operation of the f-driven electromagnetic proportional valve 26 is controlled by the control device 33. , without using the control device [33, the flow of pressure oil -St' supplied to the bottom chamber 11 is changed as shown in FIG. 3 by stroking the throttle spool 27 at a constant speed using the electromagnetic proportional valve 26. You can do it like this.

Further, although the oil amount is controlled in FIG. 1, the pressure may be controlled by interposing an electromagnetic proportional pressure valve 35 in the circuit connected to the bottom chamber 11 of the deceleration cylinder 9, as shown in FIG.

Furthermore, as shown in FIG. 7, the current from the microcomputer may be inputted to a contact governor 36 for control.

Effects of the Invention According to the present invention, when all the operating levers of the work equipment are in neutral, the engine speed initially decreases slowly from the operating setting speed to the idle speed, and then gradually decreases. Since the rate of decrease increases over time, the engine speed can be reduced even slightly at the time of interruption without impeding operability when work is interrupted for a short period of time and restarted. This makes it possible to match the working conditions with the sense of the operator, and also to avoid waste of fuel and reduce noise. Furthermore, according to the method of the present invention, the rotational speed of the engine 1 is gradually reduced in the initial stage when the work equipment is stopped, so that no shocking force is applied to the engine or hydraulic equipment at this time. , will not adversely affect the life of the engine or hydraulic equipment.

[Brief explanation of drawings]

Figures @1 to 8g5 show embodiments of the present invention,
Figure 1 is a schematic illustration of the configuration. 'g2 diagram is 1! A cross-sectional view showing the variable throttle valve part of the magnetic proportionality scale; FIG. 3 is a diagram showing changes in the flow direction of pressure oil flowing into the bottom chamber of the deceleration cylinder;
FIG. 4 is a diagram showing changes in the rotation angle of the control lever, FIG. 5 is a diagram showing changes in engine rotation speed, and FIGS. 6 and 7 are explanatory diagrams showing other embodiments. , FIG. 6 is a diagram showing changes in engine speed in a conventional example. 1 is the engine, 201Z, 20b is the operating lever, 23α
, 23b is a detector. Figure 2 Figure 3 Figure 4 Hours Figure 5 Hours

Claims (1)

[Claims] In an engine equipped with an auto-deceleration device, operating levers 20a, 20 of a working machine driven by this engine
A method for controlling an engine equipped with an auto-deceleration device, characterized in that the engine speed decreases at a curvilinear rate of change from the time when all the speeds b become neutral, from a set speed during work to an idle speed.