JP2000096627A - Engine control device for construction equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine control device for construction equipment capable of restarting an engine only by re-operating a lock lever when the key switch of the engine is ON even after the engine is automatically stopped. SOLUTION: This device is provided with an engine control means 8 for controlling the drive of an engine 1. A controller is provided with a fifth judgment means for judging whether a key switch signal according to the operation of a key switch 9 for instructing the drive of the engine 1 is outputted or not and a third processing means for outputting an engine drive signal for driving the engine 1 from an output means to the engine control means 8 when the output of a lock lever signal is judged by a first judgment means in the state where the output of the key switch signal is judged by the fifth judgment means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine such as a hydraulic shovel having a lock lever capable of switching a hydraulic circuit between an operable state and an inoperable state. The present invention relates to an engine control device for a construction machine capable of stopping an engine together with an operation.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No.
There is one disclosed in Japanese Patent No. 4517. This known technique includes a pressure regulator for controlling the driving of a directional control valve, that is, an on-off valve for disconnecting and connecting between an operating device and a pilot pump,
An operating lever for switching the open / close valve, that is, a lock lever, is provided, and an engine stop control device is provided in conjunction with the lock lever.

In this known technique, when a lock lever is operated to switch an on-off valve to a position for shutting off between a pressure regulator and a pilot pump, thereby disabling a hydraulic circuit including a directional control valve. The engine stop control device operates in conjunction with the operation of the lock lever, and the engine that has been driven up to that time can be stopped at the same time.

[0004] Meanwhile, at the site where a construction machine such as a hydraulic excavator is used, during the work such as excavation work, the work is temporarily interrupted, for example, for several tens of seconds to several minutes. The construction machine operator may perform another task or task. That is, the excavation work or the like before is restarted after several tens seconds to several minutes. In such a situation, as shown in the above-described known technology, in a configuration in which the engine is stopped simultaneously with the operation of the lock lever, when the work is restarted after several tens of seconds to several minutes, the key of the engine is turned on. It has to be fixed, which adds to the burden on the operator. When the interruption of the operation as described above is frequently repeated, the number of restarts of the engine also increases, and the trouble becomes more remarkable.

[0005] Under such circumstances, conventionally, when the lock lever is operated to cut off the operation device and the pilot pump to make the hydraulic circuit including the directional control valve inoperable, the lock lever is not used. There is a configuration in which the engine is stopped with a time delay provided for the operation. In this configuration, the engine is stopped after a lapse of time slightly longer than empirically considered necessary for the operator to resume the work, and the engine is locked before the predetermined time elapses. When the lever is operated and the operating device and the pilot pump are connected again, the interrupted work can be continued without re-operation of the engine key.

The latter prior art will be described below with reference to FIG.
This will be described based on Nos. 6 to 6. FIG. 4 is a schematic configuration diagram showing an engine control device of the conventional construction machine, FIG. 5 is a diagram showing a main configuration of a controller included in the conventional engine control device shown in FIG. 4, and FIG. 6 is shown in FIG. It is a flowchart which shows the processing procedure in a controller.

The prior art shown in FIG. 4 is provided, for example, in a hydraulic shovel. The hydraulic shovel includes a drive circuit for an engine 1 and actuators for driving a boom, an arm, a bucket, a swing body, a traveling body, and the like, that is, a hydraulic circuit 3 including a hydraulic pump 2 driven by the engine 1.
It has.

Further, one of circuit set control for keeping the hydraulic circuit 3 in an operable set state and circuit set release control for releasing the set state of the hydraulic circuit 3 by the circuit set control is selectively performed. Hydraulic circuit set control means, for example, a state in which the operating device provided in the hydraulic circuit 3 is connected to the pilot pump and can be operated by the operating device, and a state in which the operating device is disconnected from the pilot pump and cannot be operated by the operating device An electromagnetic valve 4 is provided which constitutes a selection means for selectively maintaining one of the states.

Further, a lock lever 5 operated when the operator sits in the driver's seat or stands out of the driver's seat and goes out of the driver's cab, and operates the above-mentioned solenoid valve 4 in accordance with the operation of the lock lever 5. In addition to a lock lever switch 6 for outputting a lock lever signal, an engine control means 8 for controlling the driving of the engine 1, a key switch 9 used when the engine 1 is started, a power supply 10 for the key switch 9,
And a controller 7 for inputting the lock lever signal described above, performing a signal process described below, and switching the solenoid valve 4, and outputting an engine stop signal provided to the engine control means 8.

As shown in FIG. 5, the controller 7 has an input means 11 for inputting a lock lever signal output from the lock lever switch 6, and a first determination means 15 for determining whether or not the lock lever signal has been output. When it is determined that the lock lever signal has been output by the calculating means 12, the storing means 13, and the first determining means 15 of the calculating means 12, the hydraulic circuit 3 is held in an operable circuit set state. When it is determined by the first determination means 15 that the lock lever signal has not been output, the hydraulic circuit set release signal for releasing the above-described circuit set state is output to the solenoid valve 4. Output means 14 is built in.

The calculating means 12 of the controller 7 includes, in addition to the first determining means 15 described above, a second determining means 16 for determining whether or not the lock lever signal has changed from being output to not being output. This second determination means 16
When it is determined that the state has changed from a state where the lock lever signal has been output to a state where the lock lever signal has not been output, a timer 21 for measuring a predetermined time, that is, a timer 21 is included.
The predetermined time measured by the timer 21 is set in advance. As described above, the time is slightly longer than the time empirically considered necessary for the operator to temporarily suspend the work and resume the work. This predetermined time is stored in the storage unit 13, for example.

The calculating means 12 includes a third determining means 17 for determining whether or not the timer 21 has measured the above-mentioned predetermined time, and a third determining means 17 for determining that the timer 21 has measured the predetermined time. When the engine driving stop signal is output from the output means 14 to the engine control means 8
The processing means 19 and the third determination means 17 described above
In the state where it is determined that the predetermined time has not been measured, the fourth determining means 18 for determining whether or not the lock lever signal has been output, and the fourth determining means 1
8, when it is determined that the lock lever signal is output, the hydraulic circuit set signal is selected and output means 14 is selected.
And a second processing means 20 for causing the solenoid valve 4 to output a hydraulic circuit set signal from the second processing means.

The operation of the prior art thus constructed will be described below with reference to the flowchart of FIG.

At the start of the excavation work or the like, the key switch 9 of the engine 1 is operated, and the key switch signal is given to the engine control means 8, whereby the engine 1 is driven.

In such a state, first, as shown in step S1, a lock lever signal is read into the controller 7, and as shown in step S2, the first discriminating means 15 is read.
It is determined whether or not the lock lever signal is output from the lock lever switch 6. Now, assuming that the lock lever 5 is held as shown in FIG. 4, that is, the lock lever switch 6 is closed, and the lock lever signal is determined to be on, if the lock lever 5 is not tilted in the direction of the arrow in FIG. Then, the process proceeds to step S3. In step S3, a process of outputting the hydraulic circuit set signal to the solenoid valve 4 via the output means 14 is performed. As a result, the solenoid valve 4 is switched to a position where the pilot pump (not shown) and the operating device are connected, and the hydraulic circuit 3 is maintained in an operable circuit set state. Here, by appropriately operating the operating device, the corresponding directional control valve included in the hydraulic circuit 3 is operated, and the pressure oil of the hydraulic pump 2 driven by the engine 1 is supplied to the corresponding actuator via the corresponding directional control valve. Then, a boom, an arm, a bucket, etc. are operated, and a desired excavation operation or the like is performed. During the digging operation or the like, the above-described processing and operation are repeated.

In order to temporarily suspend the excavation work and the like from such a state, the operator operates the lock lever 5 as shown in FIG.
Is tilted in the direction of the arrow to get out of the cab of the excavator, the lock lever switch 6 is opened by the operation of tilting the lock lever 5, and the discrimination by the first discriminating means 15 in step S2 in FIG. "No" and the procedure S
Move to the processing of 4. In step S4, a hydraulic circuit set release signal is output to the solenoid valve 4 via the output means 14. As a result, the solenoid valve 4 is switched to a position at which the pilot valve (not shown) and the operating device are cut off, and the hydraulic circuit is brought into an unoperable circuit set release state.

Next, the procedure proceeds to step S5, where the second discriminating means 16
Thus, it is determined whether or not the lock lever signal has changed from being output to not being output. Now, the determination is yes, and the procedure moves to step S6. In this step S6, the timer 21 starts counting. Next, the procedure moves to step S7. In this step S7, the predetermined time stored in the storage means 13 is called out, and
It is determined whether 1 has counted a predetermined time. If it is determined that the timer 21 has not counted the predetermined time in the determination by the third determination unit 17 in step S7, the process proceeds to step S8. In this step S8, the fourth determination means 18 determines whether the lock lever signal is on. That is, it is determined whether or not the operator once out of the cab has pulled back the lock lever 5 to the state shown in FIG. 4 in order to sit in the driver's seat. Assuming now that the operator has not returned to the operator's cab, the lock lever 5 has been tilted down, and the lock lever switch 6 has been kept open, the determination by the fourth determination means 18 in step S8 is ""No", and returns to the procedure S7 again.

If it is assumed that the timer 21 has counted a predetermined time due to the prolonged errand of the operator or the like, the determination by the fourth determination means 18 in step S7 is "yes" and the first processing means in steps S9 and S10. 19 is performed. That is, after the timer 21 is reset in step S9, a process of outputting an engine drive stop signal to the engine control unit 8 via the output unit 14 in step S10 is performed. The engine 1 stops when an engine drive stop signal is given to the engine control means 8.

Also, if the operator's errand is shorter than the above-mentioned predetermined time as scheduled, the operator returns to the cab and pulls back the lock lever 5 to the state shown in FIG. If this is the case, the lock lever switch 6 is closed, and the determination of the fourth determination means 18 in step S8 is "yes". Here, steps S11 and S
The processing of the third second processing means 20 is performed. That is, after the timer 21 is reset in step S11, a process of outputting a hydraulic circuit set signal to the electromagnetic valve 4 via the output means 14 in step S3 is performed. As a result, the solenoid valve 4 is operated to switch to a position for connecting a pilot pump (not shown) and the operating device, and the hydraulic circuit 3 is in an operable circuit set state. Therefore, the desired excavation work or the like can be restarted by appropriately operating the operation device again without the need to restart the engine 1.

[0020]

In the latter prior art shown in FIGS. 4 to 6 described above, even if the operator tilts the lock lever 5 and goes out of the cab, if the operator returns within a predetermined time, the lock lever 5 will not move. It is convenient that the work can be continued just by pulling back.

However, this prior art is effective when the engine 1 is not stopped, and the operation after the engine 1 is stopped is not considered. That is, in the prior art shown in FIGS. 4 to 6, if the operator returns to the cab slightly after the above-described predetermined time after the lock lever 5 is tilted, the key switch of the engine 1 is used. When the engine 9 is on, the engine 1 is stopped. Therefore, it is necessary for the operator to operate the key switch 9 once so as to be turned off and then to operate it again so as to start the engine 1. From this point of view, the prior art shown in FIGS. 4 to 6 requires a troublesome restart operation of the engine 1.

The present invention has been made in view of the above situation in the prior art, and has as its object to automatically stop the engine after a predetermined time has elapsed after the operation of the lock lever. An object of the present invention is to provide an engine control device for a construction machine that can restart an engine simply by re-operating a lock lever even after the engine is automatically stopped.

[0023]

According to one aspect of the present invention, there is provided an engine and a hydraulic circuit including a hydraulic pump driven by the engine.
Hydraulic circuit set control means for selectively performing one of circuit set control for maintaining the hydraulic circuit in an operable set state and circuit set release control for releasing the set state of the hydraulic circuit by the circuit set control; The hydraulic circuit set control means includes a lock lever for outputting a lock lever signal for executing the circuit set control, and a first determination means for determining whether or not the lock lever signal has been output. When it is determined that the lock lever signal has been output, the hydraulic circuit set signal for holding the circuit set state is
When the first discriminating means determines that the lock lever signal is not output, a built-in output means for outputting a hydraulic circuit set release signal for releasing the circuit set state to the hydraulic circuit set control means, respectively. An engine control means provided on a construction machine having a controller for controlling driving of the engine; and the controller determines whether the lock lever signal has changed from being output to not being output. A second determining means, a time measuring means for measuring a predetermined time when the second determining means determines that the lock lever signal has been changed from being output to not being output, and Third determining means for determining whether or not a predetermined time has been measured; First processing means for outputting an engine drive stop signal from the output means to the engine control means when it is determined that the time has been measured, and that the time measurement means has not measured the predetermined time by the third determination means A fourth discriminating means for discriminating whether or not the lock lever signal is output in the discriminated state; and a hydraulic circuit, when the fourth discriminating means determines that the lock lever signal is output, A second processing means for selecting a set signal and outputting the hydraulic circuit set signal from the output means to the hydraulic circuit set control means, wherein the controller issues a command to drive the engine. A fifth determination means for determining whether or not a key switch signal is output in response to the operation of the key switch. In the state where it is determined that the key switch signal is output at the stage, and when the first determination means determines that the lock lever signal is output, an engine drive signal for driving the engine is output. It is configured to include third processing means for outputting the output from the output means to the engine control means.

According to the first aspect of the present invention, assuming that the operator operates the lock lever to interrupt the operation, for example, the second lever of the controller outputs the lock lever signal. It is determined that the state has been changed to a state in which the output is not performed. This starts the measurement of the predetermined time by the timer. After that, for example, it takes longer to do business than the operator thought,
It is assumed that a time exceeding a predetermined time has elapsed before the lock lever is operated again. During this time, when the third determining means determines that the time measuring means has measured the predetermined time, the first processing means outputs an engine stop signal to the engine control means. That is, when the operator operates the lock lever again, the key switch of the engine is turned on and the engine is stopped. In such a state, when the operator who has returned from the business operation again operates the lock lever, the key switch signal is now being output (ON) by the fifth determining means of the controller. Since it is determined that the lock lever signal is being output (ON), the third processing means of the controller operates to output an engine drive signal for driving the engine from the output means of the controller to the engine control means. Is performed.

Therefore, even if the engine is automatically stopped after a predetermined time has elapsed after the operation of the lock lever as described above, only by operating the lock lever again,
That is, the engine can be restarted without the need to operate the key switch of the engine.

According to a second aspect of the present invention, in the first aspect of the present invention, the controller changes from a state where the lock lever signal is output by the second determination means to a state where the lock lever signal is not output. When it is determined that the key switch signal has been output, the fourth processing means for performing auto idle control for maintaining the engine speed at a predetermined low speed, and the fifth determination means determining that the key switch signal has been output. When the first determination means determines that the lock lever signal is being output in a state where the lock lever signal is being output and the automatic idle control is being performed by the fourth processing means, The automatic idle control by the processing means is released, and the engine drive signal from the third processing means is output from the output means to the engine control means. It is characterized in that it comprises a fifth processing means.

According to the second aspect of the present invention, if the operator operates the lock lever to interrupt the operation, the lock lever signal is output by the second determination means of the controller. It is determined that the state has been changed to a state in which the output is not performed. Accordingly, in the invention according to the second aspect, particularly, the fourth controller
The processing means performs a process of executing an auto idle control for maintaining the engine speed at a predetermined low speed lower than the rated speed, for example. That is,
An engine drive signal corresponding to the above-mentioned predetermined low speed is output from the output means of the controller to the engine control means. As a result, the engine is immediately maintained at the predetermined low speed. In addition, a predetermined measurement is started by the timing unit by the above-described determination by the second determination unit. Thereafter, for example, it is assumed that a time exceeding a predetermined time has elapsed until the operator operates the lock lever again. During this time, when the third determining means determines that the time measuring means has measured the predetermined time,
The first processing means outputs an engine stop signal to the engine control means. That is, the engine that has been driven at the predetermined low speed by the auto idle control during the predetermined time is stopped with the key switch of the engine being on when the predetermined time has elapsed. In such a state,
When the operator returning from the task again operates the lock lever, the key switch signal is now being output (on) by the fifth determination means of the controller, and the lock lever signal is output by the first determination means. State (on)
Therefore, the fifth processing means is operated, the automatic idle control by the fourth processing means is released, and the engine drive signal by the third processing means, that is, the predetermined low speed by the fourth processing means, is released. A process of outputting an engine drive signal capable of giving a rotation speed higher than the rotation speed, for example, a rated rotation speed, from the output means of the controller to the engine control means is performed.

Therefore, the invention according to claim 2 also
The engine can be restarted simply by re-operating the lock lever, that is, without having to operate the key switch of the engine, and when the lock lever is operated to interrupt work, the engine speed is reduced. The rotation speed can be reduced to the minimum required speed.

The invention according to claim 3 of the present invention is the invention according to claim 1 or 2, wherein the hydraulic circuit set control means is capable of operating with an operating device provided in the hydraulic circuit. It is a selecting means for selectively maintaining any of the states in which the operation by the operation device cannot be performed.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the selecting means is an electromagnetic valve for connecting and disconnecting between the operating device and the pilot pump. It is characterized by.

According to a fifth aspect of the present invention, in the first aspect, the construction machine is a hydraulic shovel.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an engine control device for a construction machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing a main part configuration of a controller provided in the embodiment shown in FIG. 1, and FIG. 3 shows a processing procedure in the controller shown in FIG. It is a flowchart. In FIGS. 1 and 2, the same components as those shown in FIGS. 4 and 5 are denoted by the same reference numerals.

The embodiment shown in FIG. 1 is also provided in, for example, a hydraulic shovel, similarly to the embodiment shown in FIG. This hydraulic excavator includes an engine 1 and a boom (not shown).
A drive circuit of an actuator that drives an arm, a bucket, a swing body, a traveling body, and the like, that is, a hydraulic circuit 3 including a hydraulic pump 2 driven by an engine 1 is provided.

A hydraulic pressure for selectively performing one of circuit set control for keeping the hydraulic circuit 3 in an operable set state and circuit set release control for releasing the set state of the hydraulic circuit 3 by this circuit set control. Circuit set control means, for example, a state in which the operating device provided in the hydraulic circuit 3 is connected to the pilot pump and operated by the operating device, and a state in which the operating device and the pilot pump are cut off and the operating device cannot be operated. An electromagnetic valve 4 is provided which constitutes a selection means for selectively keeping one of them.

A lock lever 5, a lock lever switch 6 for outputting a lock lever signal for operating the solenoid valve 4 in accordance with the operation of the lock lever 5, and an engine control means 8 for controlling the driving of the engine 1. And a key switch 9 of the engine 1 used at the time of starting the engine;
The power supply 10 of the key switch 9 and the above-mentioned lock lever signal are inputted, and each signal processing described later is performed to execute the electromagnetic valve 4.
And a controller 7 for outputting a signal for switching the engine and an engine stop signal given to the engine control means 8.

The present embodiment shown in FIG. 1 is different from the embodiment shown in FIG. 4 in that a key switch 9 of the engine 1 is connected to a controller 7 and a key switch output when the key switch 9 is turned on. This is a point where a signal is input to the controller 7 and a configuration of a main part of the controller 7 described later.

As shown in FIG. 2, the controller 7 has a key switch signal output from the engine key switch 9, an input means 11 for inputting a lock lever signal output from the lock lever switch 6, and a lock lever signal. When it is determined that the lock lever signal has been output by the calculating means 12 having the first determining means 15 for determining whether or not the signal has been output, the storage means 13 and the first determining means 15 of the calculating means 12 described above. A hydraulic circuit set signal for holding the hydraulic circuit in an operable circuit set state,
When the first determination unit 15 determines that the lock lever signal is not output, the output unit 14 includes a hydraulic circuit set release signal for releasing the above-described circuit set state to the solenoid valve 4. .

The calculating means 12 of the controller 7 includes, in addition to the first determining means 15 described above, a second determining means 16 for determining whether or not the lock lever signal has changed from being output to not being output. This second determination means 16
When it is determined that the state has changed from a state in which the lock lever signal is output to a state in which the lock lever signal is not output, a measuring means for measuring a predetermined time, that is, a timer 1 is included. The predetermined time measured by the timer 21 is set in advance. As described above, the time is slightly longer than the time empirically considered necessary for the operator to temporarily suspend the work and resume the work. This predetermined time is stored in the storage unit 13, for example.

The calculating means 12 includes a third determining means 17 for determining whether or not the timer 21 has measured the above-described predetermined time, and a third determining means 17 for determining that the timer 21 has measured the predetermined time. When the engine driving stop signal is output from the output means 14 to the engine control means 8
The processing means 19 and the third determination means 17 described above
In the state where it is determined that the predetermined time has not been measured, the fourth determination means 18 determines whether or not the lock lever signal is output, and the fourth determination means 18 outputs the lock lever signal. And a second processing means 20 for selecting the above-described hydraulic circuit set signal and outputting the hydraulic circuit set signal to the solenoid valve 4 from the output means 14 when the determination is made.

The components of the controller 7 of this embodiment are the same as those shown in FIG.

In this embodiment, in particular, the controller 7
A fifth determining means 22 for determining whether or not a key switch signal has been output in response to an operation of the key switch 9 for instructing driving of the engine 1, and a state in which the fifth determining means 22 outputs a key switch signal. And the first
When the determination means 15 determines that the lock lever signal is being output, a third processing means 23 for outputting an engine drive signal for driving the engine 1 to the output means 14 is provided.

The operation of the embodiment constructed as described above will be described below with reference to the flowchart of FIG. When the operator lifts the lock lever 5 to sit in the driver's seat and enters the state shown in FIG. 1, the lock lever switch 6 is closed, and a lock lever signal is output to the controller 7. Here, when the key switch 9 for commanding the start of the engine 9 is operated to start the excavation work or the like, a key switch signal is output to the controller 7.

In the controller 7, first, in step S21
As shown in (5), the key switch signal and the lock lever signal are read, and it is determined in step S22 whether the key switch signal is output by the fifth determination means 22.
In this case, the determination is "yes", and the procedure goes to step S24. When the key switch 9 is not operated, the determination of the fifth determination means 22 in this step S22 is “No”.
Then, the process proceeds to step S23, and the process is performed in which the engine drive signal is not output.

In step S24, the first determining means 15
It is determined whether or not the lock lever signal is output from the lock lever switch 6. Now, since the lock lever signal is output as described above, the first determination means 1
The determination in 5 is “yes”, and the procedure moves to step S25. In this step S25, the third processing means 23 operates to output an engine drive signal for driving the engine 1 from the output means 14 to the engine control means 8. As a result, the engine control means 8 is operated, and the rotation speed of the engine 1 is increased to, for example, a rated rotation speed suitable for performing the excavation work or the like. Next, the procedure moves to step S26. In this step S26,
A process of outputting the hydraulic circuit set signal to the electromagnetic valve 4 via the output means 14 is performed. As a result, the solenoid valve 4 is switched to a position where the pilot pump (not shown) and the operating device are connected, and the hydraulic circuit 3 is maintained in an operable circuit set state. Here, by appropriately operating an operating device (not shown), a corresponding directional control valve included in the hydraulic circuit 3 is operated, and a hydraulic pump 2 driven by the engine 1 is operated.
Is supplied to the corresponding actuator via the corresponding directional control valve, and the boom, arm, bucket, etc. are operated, and a desired excavation operation or the like is performed. During the digging operation or the like, the above-described processing and operation are repeated.

From such a state, in order to temporarily suspend the excavation work or the like, if the operator falls down the lock lever 5 in the direction of the arrow in FIG. The lock lever switch 6 is closed by the operation of tilting the lock 5, and the determination by the first determination unit 15 in step S27 in FIG.
Move to the processing of 7. In step S24, a hydraulic circuit set release signal is output to the solenoid valve 4 via the output means 14. As a result, the solenoid valve 4 is switched to a position where the pilot pump (not shown) and the operating device are cut off, and the hydraulic circuit is brought into a circuit set canceled state in which the hydraulic circuit cannot be operated.

Then, the sequence proceeds to the order S28, where the second discriminating means 16
Thus, it is determined whether or not the lock lever signal has changed from being output to not being output. Now, this determination is “yes” and the procedure moves to step S29. This procedure S
At 29, the timer 21 starts counting. Next, the procedure moves to step S30. In this step S30, the predetermined time stored in the storage means 13 is called, and the third determination means 17 is called.
It is determined whether or not the timer 21 has counted a predetermined time. If it is determined in step S30 that the timer 21 has not counted the predetermined time in the determination by the third determination unit 17, the process proceeds to step S31. This procedure S3
In step 1, the fourth determination means 18 determines whether the lock lever signal is ON. That is, it is determined whether or not the operator once out of the cab has pulled the lock lever 5 back to the state shown in FIG. 1 in order to sit in the driver's seat. Assuming now that the operator has not returned to the operator's cab, the lock lever 5 has been tilted down, and the lock lever switch 6 has been kept open, the determination by the fourth determination means 18 in step S31 is ""No", and the procedure S3 is performed again.
Return to 0.

Here, if it is assumed that the timer 21 has counted a predetermined time due to the prolonged business of the operator or the like, the determination of the fourth determination means 18 in step S30 is "Yes".
The processing by the first processing means 19 in steps S32 and S33 is performed. That is, in step S32, the timer 21
Is reset, the process of outputting an engine drive stop signal to the engine control means 8 via the output means 14 is performed in step S33. The engine 1 stops when an engine drive stop signal is given to the engine control means 8.

Also, if the operator's business is shorter than the above-mentioned predetermined time as scheduled, the operator enters the operator's cab again and takes the lock lever 5
Is pulled back to the state shown in FIG. 1, the lock lever switch 6 is closed, and the fourth determination unit 1 in step S31 is performed.
The judgment of 8 is “yes”. Here, steps S31 and S3
4 is performed by the second processing means 20. That is, after the timer 21 is reset in step S34, a process of outputting the hydraulic circuit set signal to the electromagnetic valve 4 via the output means 14 is performed in step S34. As a result, the solenoid valve 4 is operated to switch to a position for connecting a pilot pump (not shown) and the operating device, and the hydraulic circuit 3 is in an operable circuit set state. Therefore, the desired excavation work or the like can be restarted by appropriately operating the operation device again without the need to restart the engine 1.

Since the operator's business has been prolonged, the determination of the fourth determination means 18 in step S30 becomes "YES", and the operation of the first processing means 19 outputs an engine drive signal in step S33. When the engine 1 is stopped, the operator enters the cab,
It is assumed that the excavation work, etc. that had been carried out until then is to be resumed. At this time, although the engine 1 has been stopped, the key switch 9 has not been operated thereafter, so that the key switch 9 is kept on. In this state, in order for the operator to take a seat, for example,
Then, the lock lever switch 6 is closed and the lock lever signal is input to the controller 7.

Therefore, at this time, the determination by the fifth determining means 22 in step S22 of FIG. 3 is “yes” and the determination by the first determining means 15 in step S24 is “yes”. , The process of step S25 and then the process of step S26 are performed. That is, the third processing means 23 is operated, and an engine drive signal for driving the engine 1 is output from the output means 14.
Is output to the engine control means 8. As a result, the engine control means 8 is operated, and the rotation speed of the engine 1 is increased to, for example, a rated rotation speed suitable for performing the excavation work or the like. Next, in step S26, a hydraulic circuit set signal is output to the electromagnetic valve 4 via the output means 14, and the electromagnetic valve 4 is switched to a position for connecting a pilot pump (not shown) and the operating device, and the hydraulic circuit 3 is activated. It is kept in a possible set state. Therefore, similarly to the above, the appropriate directional control valve included in the hydraulic circuit 3 is operated by appropriately operating the operating device (not shown), and the pressure oil of the hydraulic pump 2 driven by the engine 1 passes through the corresponding directional control valve. A desired operation such as an excavation operation can be resumed by being supplied to the corresponding actuator.

When the key switch 9 is turned off at the end of a day's work or the like, the procedure S in FIG.
The determination in step S22 is "No", the process proceeds to step S23, and a process for not outputting the engine drive signal is performed.
Are kept stopped.

In this embodiment constructed as above, the operator temporarily suspends the excavation work or the like, operates the lock lever 5, and the erroneous work is prolonged, and the above-mentioned predetermined time elapses. Accordingly, even if the engine 1 is automatically stopped, the engine 1 can be restarted only by operating the lock lever 5 again. That is, in such a case, the temporarily interrupted work or the like can be resumed without the troublesome operation of turning on and off the key switch 9 of the engine 1.

In addition, in addition to the configuration of the above-described embodiment, when the controller 7 determines that the state of the lock lever signal has been changed from the output state to the non-output state by the second determination means 16 (the procedure shown in FIG. 3). S28) Fourth processing means for performing auto-idle control for maintaining the rotation speed of the engine 1 at a predetermined low-speed rotation speed which is much lower than the rated rotation speed suitable for the excavation work and the like, and the fifth processing means described above. In a state in which the determination means 22 determines that the key switch signal is being output (procedure S22 in FIG. 3), and a state in which the automatic idle control is being performed by the fourth processing means, the first determination means When it is determined in step 5 that the lock lever signal has been output (step S24 in FIG. 3), the automatic idle control by the fourth processing means is released, and the Jin drive signal (Step S25 in FIG. 3)
May be configured to include a fifth processing unit that outputs the data.

In this configuration, if the operator operates the lock lever 5 to interrupt the work, for example, the output from the state where the lock lever signal is output by the second determination means 16 of the controller 7 is output. It is determined that the state has been changed to a state in which it is not performed. As a result, a process is executed by the fourth processing means of the controller 7 to execute the auto idle control for maintaining the rotation speed of the engine 1 at a predetermined low rotation speed lower than the rated rotation speed up to that time, for example. That is, the output means 14 of the controller 7 outputs an engine drive signal corresponding to the above-mentioned predetermined low speed to the engine control means 8. Thus, the engine 1 is immediately maintained at the predetermined low speed. Further, the timer 21 starts measuring a predetermined time by the above-described determination by the second determination unit 16. Thereafter, for example, it is assumed that a time exceeding a predetermined time has elapsed until the operator operates the lock lever 5 again. During this time, when the third determination means 17 determines that the timer 21 has measured the predetermined time, the first determination is performed.
The processing unit 15 outputs an engine stop signal to the engine control unit 8. That is, the engine 1 that has been driven at the predetermined low speed by the auto idle control during the predetermined time is stopped with the key switch 9 of the engine 1 turned on when the predetermined time has elapsed. In such a state, when the operator who has returned from the business operation again operates the lock lever 5, the key switch signal is now being output (ON) by the fifth determining means of the controller 5, and the first determining means Since it is determined at 15 that the lock lever signal is being output (ON), the fifth processing means is activated, and the automatic idle control by the fourth processing means is released, and the third processing means 17 A process of outputting an engine drive signal from the output unit 14 of the controller 7 to the engine control unit 8 from the output unit 14 of the controller 7 is performed, that is, an engine drive signal capable of giving a higher rotation speed than a predetermined low speed rotation speed, for example, a rated rotation speed, by the fourth processing unit Is done.

With this configuration, the engine 1 can be restarted only by operating the lock lever 5 again, that is, without operating the key switch of the engine 1. In particular, with this configuration, when the lock lever 5 is operated to interrupt the operation, the rotation speed of the engine 1 can be reduced to the minimum required rotation speed, and energy saving can be realized.

[0056]

According to the invention of each claim of the present invention,
The engine automatically stops after a predetermined time has elapsed after the lock lever is operated.Even after the engine has stopped automatically, the engine can be started simply by operating the lock lever again. It is not necessary for the operator to operate the key switch of the engine as described above, and the work of the construction machine, which has been temporarily suspended, can be immediately resumed.

In particular, according to the second aspect of the present invention, when the operator temporarily suspends the work, the engine speed can be reduced to the required minimum speed, thereby realizing energy saving. it can.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an embodiment of an engine control device for a construction machine according to the present invention.

FIG. 2 is a diagram showing a main configuration of a controller provided in the embodiment shown in FIG. 1;

FIG. 3 is a flowchart showing a processing procedure in the controller shown in FIG. 1;

FIG. 4 is a schematic configuration diagram showing a conventional engine control device for a construction machine.

FIG. 5 is a diagram showing a main configuration of a controller provided in the conventional engine control device shown in FIG.

6 is a flowchart showing a processing procedure in the controller shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Hydraulic pump 3 Hydraulic circuit 4 Solenoid valve 5 Lock lever 6 Lock lever switch 7 Controller 8 Engine control means 9 Key switch 10 Battery 11 Input means 12 Calculation means 13 Storage means 14 Output means 15 First discrimination means 16 Second discrimination Means 17 Third determining means 18 Fourth determining means 19 First processing means 20 Second processing means 21 Timer (time measuring means) 22 Fifth determining means 23 Third processing means

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kimio Iino 650 Kandate-cho, Tsuchiura-shi, Ibaraki F-term in the Tsuchiura Plant of Hitachi Construction Machinery Co., Ltd. (Reference) 2D003 AA01 AB06 BA05 CA02 DA03 DA04 EA04 3G093 AA10 AA15 BA21 BA22 CA02 CA04 DB00 DB22 DB23 EA03 EC01

Claims (5)

[Claims] 1. An engine, a hydraulic circuit including a hydraulic pump driven by the engine, a circuit set control for maintaining the hydraulic circuit in an operable set state, and a release of the hydraulic circuit set state by the circuit set control. A hydraulic circuit set control means for selectively performing any one of the circuit set release controls to be performed, a lock lever for outputting a lock lever signal for performing the circuit set control by the hydraulic circuit set control means, and a lock lever signal. A first determination means for determining whether or not the lock lever signal has been output is incorporated. When the first determination means determines that the lock lever signal has been output, a hydraulic circuit set signal for holding the circuit set state is provided. When the first determination means determines that the lock lever signal is not output, the circuit control And a controller having a built-in output unit for outputting a hydraulic circuit set release signal for releasing the cut state to the hydraulic circuit set control unit. The engine control unit controls the driving of the engine. A second determining means for determining whether the controller has changed from a state in which the lock lever signal has been output to a state in which the lock lever signal has not been output; and a state in which the lock lever signal has been output by the second determining means. When it is determined that the state has not been output from the device, a timer means for measuring a predetermined time, a third determination means for determining whether or not the predetermined time has been measured, and a third determination means When it is determined that the timing means has measured the predetermined time, an engine drive stop signal is sent from the output means to the engine control. First processing means for outputting to the means,
A fourth determining means for determining whether or not the lock lever signal is output in a state where the third determining means determines that the time measuring means has not measured the predetermined time; and a fourth determining means. When it is determined that the lock lever signal is output, the second processing means selects the hydraulic circuit set signal and causes the output means to output the hydraulic circuit set signal to the hydraulic circuit set control means. In the engine control device for a construction machine, the controller includes: a fifth determination unit configured to determine whether a key switch signal associated with an operation of a key switch for instructing driving of the engine is output; In a state where it is determined that the key switch signal is being output, the lock lever signal is output by the first determination unit. An engine control device for a construction machine, comprising: third processing means for outputting an engine drive signal for driving the engine from the output means to the engine control means when it is determined that the engine control signal has been driven. 2. The engine according to claim 1, wherein the controller determines that the lock lever signal has been output from a state where the lock lever signal has been output to a state where the lock lever signal has not been output. The fourth processing means for performing the held auto-idle control, and the automatic idle control by the fourth processing means is performed in a state where the key switch signal is determined to be output by the fifth determination means. When the first determining means determines that the lock lever signal is output, the automatic idle control by the fourth processing means is released, and the engine is released by the third processing means. A fifth processing means for outputting a drive signal from the output means to the engine control means.
An engine control device for a construction machine according to the above. 3. The hydraulic circuit set control means includes a selection means for selectively maintaining a state in which operation by an operation device provided in the hydraulic circuit is possible and a state in which operation by the operation device is not possible. The engine control device for a construction machine according to claim 1 or 2, wherein 4. The engine control device for a construction machine according to claim 1, wherein said selection means is an electromagnetic valve for connecting and disconnecting between an operating device and a pilot pump. 5. The engine control device for a construction machine according to claim 1, wherein the construction machine is a hydraulic shovel.