JP2851219B2 - Hydraulic pump drive engine control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an engine for driving a hydraulic pump which is a power source of a hydraulic actuator, and more particularly to a method for controlling an engine for driving a hydraulic pump, which is highly useful in construction machinery.

[0002]

2. Description of the Related Art In a conventional method for controlling an engine for driving a hydraulic pump, as disclosed in Japanese Patent Laid-Open No. 61-255232, engine output rotation reduced in response to a manual decelerating command switch operation. The number is increased in response to a signal corresponding to the operation angle of the operation lever that commands the operation of the hydraulic actuator powered by the hydraulic pump.

[0003]

In the above prior art, when the operating lever is operated after the engine output speed is lowered in response to the operation of the dezel command switch, the engine output speed is increased. However, the hydraulic actuator operates at a speed that cannot be predicted by the operator or is higher than the maximum speed that the operator can handle, which is very dangerous. According to the present invention, even if the operating lever is operated after the engine output speed is reduced, it is possible to prevent the operator from predicting or operating the hydraulic actuator at a speed higher than the maximum limit that the operator can handle. A method for controlling an engine for driving a hydraulic pump is provided. Further, according to the present invention, even if the operator erroneously permits the engine output to be changed, if the desired operating speed of the hydraulic actuator is higher than a predetermined level, the engine output can be reduced. This prevents the risk of sudden stop or involuntary movement of the actuator due to reduction of the hydraulic actuator output.

[0004]

According to the present invention, there is provided a method for controlling an engine for driving a hydraulic pump, wherein a desired operating speed of a hydraulic actuator powered by an hydraulic pump driven by the engine is a predetermined operating speed. The level below the level, the level of a signal indicating that the engine output is allowed to change, and the desired actuation speed of the hydraulic actuator at a predetermined level. Changing the output of the engine when it is determined that the following is true and there is a signal indicating that it is allowed to change the engine output.

[0005]

In the method of controlling the engine for driving the hydraulic pump according to the present invention, it is determined that the desired operating speed of the hydraulic actuator is below a predetermined level, and it is permitted to change the engine output. The engine output is changed only when it is determined that the signal is present, so it is not determined that the desired operating speed of the hydraulic actuator is below a predetermined level, or it is allowed to change the engine output. If it is not determined that the signal indicating is present, the engine output is not changed. Therefore, it is possible to prevent the hydraulic actuator from operating at a speed higher than the maximum limit that the operator can handle, and further to prevent the hydraulic actuator from operating at a speed that the operator cannot predict.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a voltage is applied to one end of a deceleration switch 2 and a resistor 3 is applied to the other end.
Grounded through. The contact of the decel switch 2 is closed only when the operator pushes it, and the voltage level of one input terminal of the AND element 16 connected between the other end and the resistor 3 is set to High. If the operator does not press it, the contact opens, and the voltage level at one of the input terminals of the AND element 16 becomes Low. Decel switch 2
Output, that is, the voltage level of one of the input terminals of the AND element 16 functions as a signal indicating that the engine output is allowed to be changed, and when it is High, the engine output is allowed to be changed. It is determined that a signal indicating that the engine output is changed is present, and when it is Low, it is determined that there is no signal indicating that changing the engine output is permitted.

A travel operation lever (not shown) of a pilot valve (not shown) for instructing the operation of a travel rotary actuator (not shown) of the construction machine is provided with a travel rotary actuator (not shown) in its neutral position. It commands the stop of the operation, and commands the operating speed of the traveling rotary actuator according to the tilt angle from the neutral position. That is, the tilt angle of the traveling operation lever corresponds to the desired operation speed of the traveling rotary actuator. When the inclination angle exceeds a predetermined level, that is, when the desired operating speed of the traveling rotary actuator exceeds a certain level greater than zero, the contact of the traveling operation lever detection switch 6 is closed.

A work operation lever (not shown) of a pilot valve (not shown) for instructing the operation of a work actuator (not shown) for driving an arm or a bucket of a construction machine, has its neutral position in its neutral position. A command is issued to stop the operation of the work actuator, and the operation speed of the work actuator is commanded according to the tilt angle from the neutral position. That is, the tilt angle of the work operation lever corresponds to the desired operation speed of the work actuator. When the tilt angle exceeds a predetermined level, that is, when the desired operation speed of the work actuator exceeds a certain level higher than zero, the contact of the work operation lever detection switch 5 is closed.

One terminals of the work operation lever detection switch 5 and the traveling operation lever detection switch 6 are connected to each other, a voltage is supplied through the resistor 15, and the other terminals thereof are grounded. An AND is provided between the resistor 15 and one of the terminals to which the work operation lever detection switch 5 and the travel operation lever detection switch 6 are connected.
The other of the input terminals of the element 16 is connected. When one of the contacts of the work operation lever detection switch 5 and the travel operation lever detection switch 6 is closed, the AND element 1
When the other of the input terminals of 6 is grounded and becomes Low, and the contacts of both the work operation lever detection switch 5 and the travel operation lever detection switch 6 are opened, a voltage is supplied to the other input terminal of the AND element 16 and becomes High. Becomes That is, if the desired operating speed of any actuator of the construction machine exceeds some suitable level above zero, A
The other of the input terminals of the ND element 16 is grounded and becomes Low, and it is determined that the desired operating speed of the hydraulic actuator powered by the hydraulic pump driven by the engine is not lower than the predetermined operating speed level. When the desired operation speeds of both actuators are substantially zero, a voltage is supplied to the other input terminal of the AND element 16 to become High, and the desired pressure of the hydraulic actuator powered by the hydraulic pump driven by the engine is set. Is determined to be below a predetermined operating speed level.

The AND element 16 sets its output terminal to High only when both of its input terminals are High, and sets its output terminal to Low when at least one of its input terminals is Low. The F / F flip-flop 4 is AND
Each time the level of the signal input to the input terminal connected to the output terminal of the terminal 16 rises from Low to High, the output is switched from High to Low and further from Low to High. (See FIG. 3) Unless the level of the signal input to the input terminal of the F / F flip-flop 4 rises from Low to High again, the level of the output signal up to that point is maintained. That is, the operator does not press the decel switch 2 and the contact is opened, the voltage level of one of the input terminals of the AND element 16 is set to Low, and / or the desired operating speed of any actuator of the construction machine is zero. A certain level of the work operation lever detection switch 5 and the travel operation lever detection switch 6 is closed, and the voltage level of the other input terminal of the AND element 16 is set to Low. Then, after the output terminal of the AND element 16 is set to Low, the operator pushes the deceleration switch 2 to close its contact,
The voltage level of one of the input terminals of the D element 16 is set to High, and the desired operation speed of both actuators of the construction machine is higher than zero without exceeding an appropriate level. The work operation lever detection switch 5 and the travel operation lever detection are performed. When both contacts of the switch 6 are opened and the voltage level of the other input terminal of the AND element 16 is set to High, AND
The output terminal of the element 16 rises from Low to High, and in the F / F flip-flop 4, the level of the signal input to its input terminal connected to the output terminal of the AND element 16 rises from Low to High and its input terminal Each time the level of the signal input to the signal rises from Low to High, its output is changed from High to Low or Lo.
Switch from w to High. This means that the desired operating speed of both actuators of the construction machine does not exceed a certain level (which may be approximately zero) that is greater than zero, and the contacts of both the work operation lever detection switch 5 and the travel operation lever detection switch 6 are contacted. When it is opened, or when the desired operating speed of both actuators of the construction machine is greater than zero and does not exceed a certain level, the contacts of both the work operation lever detection switch 5 and the travel operation lever detection switch 6 are opened. However, this means that the output of the F / F flip-flop 4 does not switch from High to Low or from Low to High.

When the fact that the output of the F / F flip-flop 4 is High is input to the microcomputer 7, the microcomputer 7 uses the engine speed setting dial 1 for analog-digital conversion. The set engine speed input to the microcomputer 7 via the converter 8 is reduced to a predetermined low engine speed effective for fuel saving or low noise. Such a state is called a deceleration operation state. The rotation speed control of the engine 11 by the microcomputer 7 supplies a voltage corresponding to a desired engine speed from the microcomputer 7 to the drive circuit 9, and the drive circuit 9 supplies a current corresponding to the desired engine speed. Applied to the actuator 12, the actuator 12 generates a displacement corresponding to a desired engine speed, and the link 1
It is performed by displacing the governor lever 14 of the engine 11 by a distance corresponding to a desired engine speed via the control unit 3. When the fact that the output of the F / F flip-flop 4 is Low is input to the microcomputer 7,
The microcomputer 7 includes a drive circuit 9 and an actuator so that the actual engine speed is maintained at the set engine speed input to the microcomputer 7 via the analog-digital converter 8 by the engine speed setting dial 1. The governor lever 14 of the engine 11 is controlled via 12 and the link 13. Such a state is called a normal operation state. The rotation speed sensor 10 is
The actual engine speed is measured and fed back to the microcomputer 7,
Corrects the output signal to the drive circuit 9 so that the difference between the desired engine speed and the actual engine speed becomes small.

The desired operating speed of both actuators of the construction machine does not exceed a certain level (which may be approximately zero) greater than zero, and the work operation lever detection switch 5
When both the contacts of the traveling operation lever detection switch 6 and the traveling operation lever detection switch 6 are opened, if the deceleration switch 2 is already pressed and the contacts are closed, switching is performed between the deceleration operation state and the normal operation state. Alternatively, when the desired operating speeds of both actuators of the construction machine do not exceed a certain level higher than zero and the contacts of both the work operation lever detection switch 5 and the travel operation lever detection switch 6 are opened,
If the decel switch 2 is pressed and its contacts are closed,
Switching is performed between the decel operation state and the normal operation state. Therefore, as shown in FIG.
Is already pushed and its contacts are closed, the desired operating speeds of both actuators of the construction machine do not exceed a certain level (which may be almost zero) greater than zero and the work operation lever detection switch 5 and the traveling When both contacts of the operating lever detection switch 6 are opened, or the desired operating speed of both actuators of the construction machine is greater than zero and does not exceed a certain level, the work operating lever detection switch 5 and the traveling operating lever detection switch 6 Only when the decel switch 2 is pressed and both contacts are closed while both contacts are open, switching between the decel operation state and the normal operation state is performed.

F / F flip-flop 4 and AND element 1
6 is not used, that is, the hard wire logic is not used, the signal voltage from the work operation lever detection switch 5, the travel operation lever detection switch 6 and the deceleration switch 2 is directly input to the microcomputer, and the software log (See FIG. 4), the substantially same function as described above may be achieved. First, it is determined whether or not the decel switch 2 has been pressed and the signal voltage level from that point has risen from Low to High. In the routine shown in FIG. 4, the signal voltage level input last time is stored in the memory, and when it is Low, and the signal voltage level input this time in the routine shown in FIG. 4 is High, It is judged that the decelerating switch 2 is pushed and the signal voltage from it rises from Low to High, and then the desired operating speeds of both actuators of the construction machine are higher than zero. ) Is not exceeded, or both the work operation lever and the travel operation lever are not operated, and it is judged whether or not the contacts of both the work operation lever detection switch 5 and the travel operation lever detection switch 6 are open. enter. If it is determined that the signal voltage level does not rise from Low to High, the switching between the decel operation state and the normal operation state is not performed. It is determined that the decel switch 2 has been pressed, the signal voltage level from it has risen from Low to High, and the desired operating speeds of both actuators of the construction machine are higher than zero. If it is determined that both the work operation lever and the travel operation lever are not operated and the contacts of both the work operation lever detection switch 5 and the travel operation lever detection switch 6 are open, Until the deceleration operation state,
It is switched to the normal operation state, and if it is the normal operation state until then, it is switched to the deceleration operation state. Even if it is determined that the decel switch 2 has been pressed and the signal voltage level from it has risen from Low to High, the desired operating speed of at least one actuator of the construction machine is higher than zero. ), Or at least one of the work operation lever and the travel operation lever is operated, and the contact of at least one of the work operation lever detection switch 5 and the travel operation lever detection switch 6 is closed, the deceleration operation state is established. There is no switching between normal operating conditions. That is, the desired operating speed of both actuators of the construction machine does not exceed some suitable level (which may be approximately zero) greater than zero.
Alternatively, the switching between the deceleration operation state and the normal operation state is performed only when both the work operation lever and the travel operation lever are not operated.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an engine control system according to the present invention.

FIG. 2 is a diagram showing an example of switching logic between a normal operating state and a decelerating operating state according to a decelerating switch operating state and an operating lever position state according to the present invention.

FIG. 3 is a diagram showing a relationship between an input state and an output state of an F / F flip-flop element used in an embodiment of the present invention.

FIG. 4 is a flowchart showing another embodiment of the present invention.

[Explanation of symbols]

 1 Engine speed setting dial 2 Decel switch 4 F / F flip-flop 5 Work control lever detection switch 6 Travel control lever detection switch 7 Microcomputer 11 Engine 14 Governor lever 16 AND element

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-176633 (JP, A) JP-A-61-255232 (JP, A) Actually opened 61-192542 (JP, U) Actually opened 2- 40743 (JP, U) (58) Fields investigated (Int.Cl. ⁶ , DB name) F02D 29/04

Claims (8)

(57) [Claims] 1. A method for controlling an engine for driving a hydraulic pump, wherein it is determined whether or not a desired operating speed of a hydraulic actuator powered by an hydraulic pump driven by the engine is below a predetermined operating speed level. And determining whether there is a signal indicating that it is allowed to change the engine output, the desired actuation speed of the hydraulic actuator is determined to be below a predetermined level, and Increasing the output of the engine when it is determined that there is a signal indicating that changing the engine output is allowed, and controlling the hydraulic pump driving engine. 2. The predetermined operating speed level is substantially zero,
A method for controlling an engine for driving a hydraulic pump according to claim 1. 3. When it is determined that the desired actuation speed of the hydraulic actuator is below a predetermined level and, at about the same time, it is determined that there is a signal indicating that the engine output is allowed to change. The method for controlling an engine for driving a hydraulic pump according to claim 1, wherein the output of the engine is increased . 4. A method of determining that the desired operating speed of the hydraulic actuator is not below a predetermined level, and then determining that the desired operating speed of the hydraulic actuator is below a predetermined level, and changing the engine output. The method for controlling an engine for driving a hydraulic pump according to claim 1, wherein the output of the engine is increased when it is determined that there is a signal indicating that is permitted. 5. The desired actuation speed of the hydraulic actuator is determined to be less than or equal to a predetermined level after it is determined that there is no signal indicating that changing the engine output is allowed, and the engine output The method for controlling an engine for driving a hydraulic pump according to claim 1, wherein the output of the engine is increased when it is determined that there is a signal indicating that the change is allowed. 6. The output of the engine when it is determined that the desired operating speed of the hydraulic actuator is below a predetermined level and there is a signal indicating that it is allowed to change the engine output. And then the hydraulic actuator is determined to be not below the desired operating speed of the hydraulic actuator or there is no signal indicating that it is permissible to change the engine output. The hydraulic pump drive that increases the output of the engine when it is determined that the desired operating speed of the engine is below a predetermined level and there is a signal indicating that it is allowed to change the engine output. Engine control method. 7. A method of controlling an engine for driving a hydraulic pump, which prevents increasing the output of the engine when it is determined that the desired operating speed of the hydraulic actuator is higher than a predetermined level. 8. The desired operating speed of the hydraulic actuator is
It is judged to be below a predetermined level, and the engine output
There is a signal that it is allowed to change the force
When it is judged that, increase the output of the engine,
Then, the desired operating speed of the hydraulic actuator is adjusted to the desired level.
It is judged that it is not below the bell or the engine output is changed.
There is no signal indicating that permission to activate
Desired operation of the hydraulic actuator after
It is judged that the speed is below a predetermined level, and
A signal indicating that it is allowed to change the gin output
When it is determined that the
A method for controlling an engine for driving a hydraulic pump.