JPH0953479A - Engine control device of construction vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To return a throttle to a designated low rotation position when an engine is stopped so as to reduce the engine burden at the next time of starting the engine. SOLUTION: When an operator turns on a key switch 6, a controller 7 drives an engine stop motor 12 to be open, so that an engine 9 is started. The control input of a throttle 1 is detected by a potentiometer 2, and according to the detection signal, the controller 7 controls a governor driving motor 11 to adjust the rotating speed of the engine 9. When an operator turns off the key switch 6, the controller 7 drives the engine stop motor 12 to close, so that the engine 9 is stopped. The stop of the engine is detected by a rotating speed sensor 10, and according to the detection signal, the controller 7 controls a throttle driving motor 5 to return the throttle 1 to a designated low rotation position (e.g. idling position).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction vehicle, and more particularly to an engine control device for a construction vehicle having a throttle for adjusting an engine speed.

[0002]

2. Description of the Related Art Known technologies relating to this type of engine control device include, for example, the following. [Patent Document 1] Japanese Unexamined Patent Publication No. 5-222961 In this known technique, after a command to stop the engine, driving of the control device is continued for a predetermined time to stop the motor that drives the governor at a fixed position, and then the control device is stopped. .
As a result, the governor is always held at a fixed stop position, and the startability and reliability at the next engine start are improved.

[0003]

However, the above-mentioned known technique has the following problems. That is, when the governor is held at a fixed stop position after the engine stop command, the throttle (accelerator lever) stops while holding the position where the engine was stopped. Therefore, when the engine is started next time, immediately after the engine is started, the engine speed rapidly increases to the throttle position when the engine was stopped last time. Therefore, there is a possibility that the engine and the hydraulic equipment will be warmed up in the cold season before they are fully warmed up. In this case, the engine is heavily burdened.

Therefore, the present invention provides an engine control device for a construction vehicle capable of reducing the engine load at the next engine start by returning the throttle to a predetermined low rotation position when the engine is stopped.

[0005]

In order to achieve the above object, according to the present invention, a key switch for starting and stopping an engine, a throttle for adjusting the number of revolutions of the engine, and this throttle are provided. Operation amount detecting means for detecting the operation amount of the engine and outputting a corresponding detection signal, and when the key switch is ON, the engine is started and the engine speed is adjusted according to the detection signal from the operation amount detecting means. An engine control device for a construction vehicle having a rotation control means for stopping the engine when the key switch is OFF, and a throttle driving means for driving the throttle, and detecting a stop of the engine and outputting a corresponding detection signal. Stop detection means for operating the throttle valve when the stop of the engine is detected by the stop detection means. The engine control system for a construction vehicle, characterized in that it comprises a throttle driving control means for returning the said throttle by controlling the motion means to a predetermined low rotational position is provided.

That is, in the present invention configured as described above, when the operator turns on the key switch,
The rotation control means drives the engine stop motor to an open state to start the engine. At this time, on the other hand, the operation amount of the throttle is detected by the operation amount detection means, and the rotation control means adjusts the rotation speed of the engine by controlling the governor drive motor for driving the governor, for example, according to the detection signal. . When the operator turns off the key switch, the rotation control means stops the engine by driving the engine stop motor to a closed state, for example. Then, the stop of the engine is detected by stop detection means such as a rotation speed sensor, and the throttle drive control means controls the throttle drive means in response to the detection signal to set the throttle to a predetermined low rotation position (for example, idling position). Back up. Therefore, when the operator tries to start the engine next time, the throttle is already in the low rotation position, so that when the engine is started, the engine automatically starts from a predetermined low rotation speed (for example, idling rotation speed). Can be made.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
~ It demonstrates by FIG. FIG. 1 is a conceptual diagram showing the overall configuration of an engine control device for a construction vehicle according to this embodiment.
In FIG. 1, the engine control device according to the present embodiment is
A key switch 6 operated by an operator for starting and stopping the engine 9, a governor 8 for adjusting a fuel supply amount to the engine 9, and a governor 8 for controlling an engine 9 provided in a hydraulic excavator or the like. A governor drive motor 11 for driving the engine, an engine stop motor 12 for supplying and shutting off fuel to the engine 9, a throttle device 13 provided with a throttle 1 operated by an operator for adjusting the rotational speed of the engine 9, and a throttle device Operation amount detecting means for detecting the operation amount of No. 1 and outputting a corresponding detection signal, for example, potentiometer 2, throttle driving means for driving throttle 1, for example, throttle drive motor 5, and detection of stop of engine 9 and corresponding detection. Stop detection means for outputting a signal, for example, engine speed sensor 10
And a controller 7.

The detailed structure of the throttle device 13 is shown in FIGS. FIG. 2 is a front view of the throttle device 13,
3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is taken along line IV- in FIG.
It is IV sectional drawing. 2 to 4, the throttle device 13 is one stopper 3 provided on the throttle 1 side.
And two stoppers 4a and 4b provided on the throttle device main body 14 side. The throttle 1 has a low to high rotational speed within an operable range restricted by these stoppers 3, 4a and 4b. The operator can arbitrarily set the number of revolutions between them. Further, the potentiometer 2 and the throttle drive motor 5 are mounted coaxially with the throttle 1.

The operation in the above configuration is performed by the controller 7
This will be described with reference to FIG. 5, which is a flowchart showing the control contents by the above. When the operator turns on the key switch 6 with the intention of starting the engine 9, the controller 7 is also turned on and the flow of FIG. 5 is started.

First, in step 101, a drive signal is output to the engine stop motor 12 to output the engine stop motor 1
Open 2 As a result, fuel is supplied to the engine 9 and the engine 9 starts.

Next, the procedure moves to step 102, and a detection signal from the potentiometer 2 indicating the operation amount of the throttle 1 is input. The controller 7 calculates the output value of the drive signal for driving the governor 8 to the position corresponding to this detection signal,
In step 103, the drive signal having the calculated value is output to the governor drive motor 11. As a result, the engine 9 rotates at the number of revolutions corresponding to the operation position of the throttle 1 at this time.

Then, in step 104, after inputting the signal from the key switch 6, it is determined in step 105 whether the key switch is OFF. The operator intends to continue the rotation of the engine 9 and turns on the key switch.
If it is left as it is, this condition is not satisfied, and the procedure returns to step 102 and steps 102 to 105 are repeated.

When the operator turns off the key switch 6 with the intention of stopping the engine 9, the procedure 105 is performed.
When the condition of is satisfied, the procedure proceeds to step 106. In step 106, a drive signal is output to the engine stop motor 12 to close the engine stop motor 12. This cuts off the fuel supply to the engine 9,
Stops.

Then, in step 107, a signal from the engine speed sensor 10 is input, and in step 108, it is judged whether the engine 9 is rotating based on this signal. If the engine 9 is still rotating without stopping, the procedure returns to step 107 and steps 107 and 108 are repeated. If the engine 9 has stopped, the process proceeds to step 109.

In step 109, a drive signal is output to the governor drive motor 11 so that the governor 8 returns to a predetermined low rotation position (for example, an idling position). And step 1
Move to 10.

In step 110, the throttle 1 is returned to a predetermined low rotation position (for example, an idling position),
A drive signal is output to the throttle drive control motor 5.

Then, in step 111, the potentiometer 1
After the detection signal from 11 is input, in step 112, it is determined based on this detection signal whether or not the throttle 1 has returned to the low rotation position. If the throttle 1 has not yet returned to the low rotation position, the process returns to step 110 and steps 110 to 112 are repeated. When the throttle 1 has returned to the low rotation position, the procedure proceeds to step 113.

In step 113, the controller 7 powers itself off, and this flow ends.

In the above, the controller 7
The rotation control means starts the engine 9 when the key switch 6 is ON, adjusts the rotation speed and stops the engine 9 when the key switch 6 is OFF, and controls the throttle drive means when the engine stop is detected to control the throttle. A throttle drive control means for returning 1 to a predetermined low rotation position is configured.

As described above, in the engine control system of this embodiment, when the key switch 6 is turned off and the engine 9 is stopped, the controller 7 controls the throttle drive motor 5 to set the throttle 1 to a predetermined position. It is returned to the low rotation position. Therefore, when the operator tries to start the engine 9 next time, the throttle 1 is already in the low rotation position, and therefore the low rotation speed (for example, a predetermined idling rotation speed) is automatically set when the engine is started. You can start from. Therefore, unlike the conventional case, when the engine / hydraulic equipment needs to be warmed up, the engine / hydraulic equipment does not rotate at a high rotation speed at the same time as starting, so that the load on the engine 9 and the hydraulic equipment can be reduced.

[0021]

According to the present invention, after the operator stops the engine once and then tries to start the engine next time, the engine automatically changes from a predetermined low rotation speed (for example, idling rotation speed). It can be started. Therefore, unlike the conventional case, the engine speed does not rapidly increase immediately after the engine is started, and the full throttle does not occur before the engine and hydraulic equipment are warmed up. Can be reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an overall configuration of an engine control device for a construction vehicle according to an embodiment of the present invention.

FIG. 2 is a front view of the throttle device shown in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

5 is a diagram showing a flowchart showing the control contents by the controller shown in FIG. 1. FIG.

[Explanation of symbols]

1 Throttle 2 Potentiometer (operation amount detecting means) 3 Stoppers 4a, b Stopper 5 Throttle drive motor (throttle drive means) 6 Key switch 7 Controller (rotation control means, throttle drive control means) 8 Governor 9 Engine 10 Engine speed sensor ( Stop detection means) 11 Governor drive motor 12 Engine stop motor 13 Throttle device 14 Throttle device body

Claims (1)

[Claims] 1. A key switch for starting and stopping an engine, a throttle for adjusting the number of revolutions of the engine, and an operation amount detecting means for detecting an operation amount of the throttle and outputting a corresponding detection signal. , Rotation control means for starting the engine when the key switch is ON, adjusting the engine speed in accordance with a detection signal from the operation amount detection means, and stopping the engine when the key switch is OFF. In an engine control device for a construction vehicle having the above, a throttle drive means for driving the throttle, a stop detection means for detecting a stop of the engine and outputting a corresponding detection signal, and a stop of the engine is detected by the stop detection means. Control the throttle driving means to return the throttle to a predetermined low rotation position. The engine control system for a construction vehicle, characterized in that it comprises a throttle driving control means for.