JP2008057468A - Engine control device of work machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform the restart of an engine after temporary stop in an excellent state while saving energy by temporarily stopping the engine which is unnecessarily operated in an engine control device of a work machine. <P>SOLUTION: This work machine comprises an engine 10 as the drive source, a cooling water temperature sensor 41 detecting the temperature of a cooling water for cooling the engine 10, an oil temperature sensor 42 detecting the temperature of a hydraulic oil for operating the work machine, and an engine control means 30 having an engine stop function for stopping the engine 10 when the state that the work machine is not operated is continued for a predetermined time when the temperature of the cooling water detected by the cooling water temperature sensor 41 and the temperature of the hydraulic oil detected by the oil temperature sensor 42 are within predetermined ranges, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine control device for a work machine.

Work machines represented by hydraulic excavators are often put into various sites such as building construction sites and road construction sites. In addition, work machines often have a long work standby time due to balance with other work on site, and it is generally said that about 30% of the engine operating time is in an idling operation state. It has been broken.
In view of this, from the viewpoint of energy saving and environmental protection, an engine control device has been developed for the purpose of reducing unnecessary idling operation as much as possible.

For example, in Patent Document 1, a stop switch for temporarily stopping the engine is provided on the operation lever when the state in which the work machine is not operated exceeds a preset time, or the operator can arbitrarily stop the stop switch. A technique for stopping the engine when operating is described.
Patent Document 2 discloses a technique for stopping the engine after a preset time has elapsed since the construction machine (work machine) is not operated and the operator detects that he is not in the driver's seat. Are listed.

Patent Document 3 describes a technique for stopping the engine when it is determined that the idling operation state has continued for a predetermined time.
JP 2003-65097 A JP 2002-13425 A JP 2005-163698 A

By the way, if the engine cooling water temperature or hydraulic oil temperature is low or high, and the engine is stopped, when it is restarted shortly thereafter, the engine is not fully warmed up or close to overheating. Or drive in.
In other words, if the engine is stopped when the engine coolant temperature or the hydraulic oil temperature is low, the engine coolant temperature or the hydraulic oil temperature will rise appropriately even if the engine is restarted immediately after the engine is stopped. It takes time, and the operation is resumed without sufficiently warming up. At the same time as the engine is stopped, the operation of the radiator that cools the engine coolant and the oil cooler that cools the hydraulic oil is also stopped. Therefore, if the engine is stopped while the engine coolant temperature or hydraulic oil temperature is high, the radiator or oil cooler will not perform cooling, so the engine coolant temperature and hydraulic oil temperature will not drop and remain high. When the operation is resumed shortly thereafter, the engine cooling water or hydraulic oil may be hot and may be operated in a state close to overheating.

However, none of the techniques described in Patent Documents 1 to 3 takes into account the engine cooling water temperature and the hydraulic oil temperature as described above, and it takes time to resume operation or overheats the work. There is a risk of being unable to do so.
The present invention has been devised in view of such a problem, and it is possible to perform restart after a temporary stop of the engine in a good state while temporarily stopping an engine that is operated unnecessarily to save energy. An object of the present invention is to provide an engine control device for a work machine.

  In order to achieve the above object, an engine control device for a work machine according to a first aspect of the present invention includes an engine that is a drive source of the work machine, a cooling water temperature sensor that detects a temperature of cooling water that cools the engine, and An oil temperature sensor for detecting a temperature of hydraulic oil for operating the work machine, a temperature of the cooling water detected by the cooling water temperature sensor, and a temperature of the hydraulic oil detected by the oil temperature sensor, respectively And engine control means having an engine stop function for stopping the engine when the working machine is not working for a predetermined time when it is within a predetermined range.

  An engine control device for a work machine according to a second aspect of the present invention is the engine control device for the work machine according to the first aspect, wherein an ON / OFF operation is performed by an operator in order to validate the engine stop function of the engine control means. A lock switch that enables the engine stop function when being turned ON by an operator, and disables the engine stop function when being turned OFF by the operator. Yes.

  According to the engine control device for a work machine of the first aspect of the present invention, when the operation of the engine is unnecessary, such as when the work machine is not operated for a predetermined time, the engine is stopped, Energy saving can be achieved. At the same time, the engine is stopped when the temperature of the cooling water or the temperature of the hydraulic oil is within a predetermined range. Therefore, when restarting after a temporary stop of the engine, the engine is operated without sufficiently warming up or close to overheating. Driving in a state can be prevented. Therefore, the engine can be restarted in a good state without taking time to resume operation or being overheated.

  According to the engine control device for a work machine of the second aspect of the present invention, the engine stop function is effective only when the lock switch is turned ON by the operator. It is possible to prevent the engine from being inadvertently stopped.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[One Embodiment]
1 to 5 show an engine control device for a working machine according to an embodiment of the present invention. FIG. 1 is a schematic block diagram thereof, and FIG. 2 is a perspective view of a hydraulic excavator equipped with the engine control device. 3 to 5 are flowcharts performed by the engine control device.

<Configuration>
As shown in FIG. 2, a hydraulic excavator 1, which is a typical example of a work machine, includes a lower traveling body 2, an upper revolving body 3 that is pivotably coupled on the lower traveling body 2, and a forward direction from the upper revolving body 3. The working device 7 includes a boom 4, an arm 5, and a bucket 6 that are attached so as to extend, and a cab 8 that is installed at the left front portion of the upper swing body 3.

  As shown in FIG. 1, the hydraulic excavator 1 includes an engine (internal combustion engine) 10 as a drive source, a main hydraulic pump 11 that is driven by the engine 10 and discharges hydraulic oil, and is driven by the engine 10 to generate a pilot pressure. A pilot pump 12 to be supplied, a plurality of actuators 21 to 25 that are operated by hydraulic oil discharged from the main hydraulic pump 11, and a plurality of hydraulic oils that control supply of hydraulic oil from the main hydraulic pump 11 to the plurality of actuators 21 to 25 A control valve unit 13 having control valves 13a to 13e, an operation lever 14 for operating the hydraulic excavator 1 by controlling the valve openings of the control valves 13a to 13e using the pilot pressure from the pilot pump 12, and Controller for controlling the engine 10 (engine control hand ) And a 30.

  Furthermore, a radiator 15 that cools the engine coolant, an oil cooler 16 that cools the hydraulic oil, a cooling fan 17 that introduces cooling air into the radiator 15 and the oil cooler 16, and a hydraulic oil tank (not shown) that stores the hydraulic oil. 18), a cooling water temperature sensor 41 attached to the radiator 15 for detecting the temperature (hereinafter referred to as cooling water temperature) Tw of the engine cooling water, and a hydraulic oil temperature (hereinafter referred to as oil temperature) To attached to the hydraulic oil tank. And an oil temperature sensor 42 to be detected. The cooling water temperature sensor 41 and the oil temperature sensor 42 are configured to output detected values (cooling water temperature Tw and oil temperature To) to the controller 30, respectively.

  The plurality of actuators 21 to 25 include a traveling motor 21 for traveling the lower traveling body 2, a turning motor 22 for rotating the upper revolving body 3, and working devices for the boom 4, the arm 5, and the bucket 6. Each has a boom cylinder 23, an arm cylinder 24, and a bucket cylinder 25 (see FIG. 2). And each actuator 21-25 operate | moves with the hydraulic fluid discharged from the main hydraulic pump 11, as mentioned above, it travels with the lower traveling body 2, turns with the upper revolving body 3, and the working devices 4 ~ 6 can work.

Here, one control valve 13 a to 13 e is provided for each of the actuators 21 to 25, and is disposed inside the upper swing body 3 as an assembly called the control valve unit 13.
The operation lever 14 is disposed in the cab 8 and has a plurality of remote control valves 14a for controlling the pilot pressure, and any one of the remote control valves 14a is activated in accordance with the operation state of the operation lever 14. ing. Each of the plurality of remote control valves 14 a is interposed on a pilot circuit indicated by a broken line in FIG. 1 between the pilot pump 12 and the control valve unit 13. In FIG. 1, only one remote control valve 14a is shown in a simplified manner. When one remote control valve 14a is activated, a pilot pressure is applied to the corresponding control valve (for example, 13a), the valve opening degree and the spool position of the control valve 13a are controlled, and the control valve 13a corresponds to the control valve 13a. The hydraulic oil is supplied to the actuator (for example, the traveling motor 21). That is, the predetermined actuators 21 to 25 are operated via the operation of the remote control valve 14a and the control valves 13a to 13e corresponding to the operation state of the operation lever 14. Further, the operation lever 14 is provided with a lever sensor 43 that detects the operation state and transmits a lever signal to the controller 30 when it is detected that the operation lever 14 is in the operation state.

  In the cab 8, in addition to the operation lever 14, a hydraulic lock switch (lock switch) 51 for locking the operation of all the actuators 21 to 25, and the engine 10 is started (including restart) or stopped (temporarily). A key switch (restart switch) 52 that is operated by an operator to include a stop, an accelerator dial 53 for setting the rotational speed Ne of the engine 10, and a monitor 54 on which characters are displayed are provided. ing.

  The hydraulic lock switch 51 is a switch that is turned ON / OFF by the operator to shut off the pilot circuit connected to the remote control valve 14a of the operation lever 14 and lock all the operations (running, turning, and work) of the work machine. In the ON position, a lock ON signal is output to the controller 30, and in the OFF position, no signal is output to the controller 30.

  Here, a bypass valve 55 is interposed between the remote control valve 14a and the pilot pump 12 of the pilot circuit. The bypass valve 55 is a two-position electromagnetic switching valve that is controlled by the controller 30 that receives a lock signal from the hydraulic lock switch 51. The bypass valve 55 is a lock position 55a that shuts off the pilot circuit, and an unlock position 55b that communicates the pilot circuit. And have.

  When the hydraulic lock switch 51 is turned on, the bypass valve 55 is switched to the lock position 55a under the control of the controller 30 to shut off the pilot circuit (set to the locked state). At this time, the pilot pressure does not rise with respect to the remote control valve 14a of the operation lever 14, the spool positions of all the control valves 13a to 13e are fixed at the neutral position, and the hydraulic oil is not supplied to all the actuators 21 to 25. That is, it becomes a state which cannot perform all the said operations concerning the hydraulic system of the hydraulic shovel 1. Conversely, when the hydraulic lock switch 51 is turned OFF, the bypass valve 55 is switched to the unlock position 55b under the control of the controller 30, the pilot circuit is released from the locked state, and each control valve 13a to 13e is used to The hydraulic oil can be supplied to the actuators 21 to 25.

  The engine 10 is started only when the hydraulic lock switch 51 is in the ON state. In addition, although not particularly illustrated, the hydraulic lock switch 51 is a lever switch composed of a tiltable lever provided on the side of the elevator opening on the side of the operator seat in the cab 8, and the lever is in an upright state. The hydraulic lock switch 51 is turned on, and the hydraulic lock switch 51 is turned off when the lever is tilted.

  The key switch 52 is a switch that is turned on / off when an operator inserts an ignition key into a key cylinder (not shown) and rotates it to a predetermined position. The key switch 52 is turned on and off (hereinafter referred to as the ST position). Position. Here, at the ON position, electric power is supplied from an unillustrated power source (for example, a battery) to the electrical components, and the power source and the controller 30 are connected to supply power to the controller 30. At the ST position, fuel supply is started and the engine is started. In the OFF position, power is not supplied from the power source to the electrical components, and the fuel supply is cut off at the same time as the connection between the power source and the controller 30 is cut off, and the engine 10 is stopped. As described above, if the hydraulic lock switch 51 is not in the ON state, the engine 10 is not started when the key switch 52 is in the ST position.

  The key switch 52 transmits a key ON signal to the controller 30 when operated to the ON position, and transmits a key ST signal (start and restart signal) to the controller 30 when operated to the ST position. When it is operated, no signal is transmitted. The key switch 52 is configured so that the ignition key automatically and automatically returns from the ST position to the ON position.

  The accelerator dial 53 is a dial type switch for setting the rotational speed Ne of the engine 10. Here, the engine speed Ne can be set in stages (for example, in 10 stages) by an arbitrary operation of the operator. The accelerator dial 53 outputs the set accelerator dial value (for example, “1” to “10”) to the controller 30.

  The engine 10 detects a fuel injection device 19 having an electronic governor, a pump, and the like that injects a predetermined amount of fuel appropriately set based on a command output from the controller 30 toward the engine 10, and an engine speed Ne. An engine speed sensor 44 that outputs to the controller 30 is attached. The engine 10 is started by operating the key switch 52 by the operator, and restarting after the engine 10 is temporarily stopped is also performed by operating the key switch 52 by the operator.

A cooling water temperature sensor 41, an oil temperature sensor 42, a lever sensor 43, an engine speed sensor 44, a hydraulic lock switch 51, a key switch 52, and an accelerator dial 53 are connected to the controller 30 on the input side. On the other hand, the fuel injection device 19, the monitor 54, and the bypass valve 55 are connected to the output side.
The controller 30 includes a storage unit 31 that stores predetermined values of various parameters, a determination unit 32 that determines various states of the excavator 1, a control unit 33 that controls the engine 10, and a monitor. 54 has a display unit 34 for displaying characters.

Further, the controller 30 has an engine stop function, an engine restart function, and an engine speed return function, which will be described later.
Specifically, the storage unit 31 includes a specified range (predetermined range) related to the oil temperature To that is preset as a preferable temperature range of the oil temperature To, and a cooling water temperature Tw that is preset as a preferable temperature range of the cooling water temperature Tw. The specified range (predetermined range) according to the above is stored. The storage unit 31 is configured to store a preset low idle rotational speed Ne _la as the rotational speed in the low idle state.

  The determination unit 32 is a controller that performs determinations related to various states of the excavator 1 based on numerical values and signals input from the sensors 41 to 44 and the switches 51 and 52. For example, the determination unit 32 includes: Then, it is determined whether or not the coolant temperature Tw detected by the coolant temperature sensor 41 is within a specified range stored in the storage unit 31. Similarly, it is determined whether or not the oil temperature To detected by the oil temperature sensor 42 is within a specified range stored in the storage unit 31.

The determination unit 32 determines whether or not the operation lever 14 is operated and there is an operation request based on the lever signal input from the lever sensor 43.
The determination unit 32 determines whether the engine 10 is operating or whether the engine 10 is operating and in a low idle state based on the engine speed Ne detected by the engine speed sensor 44. It is supposed to be. Here, if the engine speed Ne is 0 rpm, it is determined that the engine 10 is in a stopped (temporary stop) state, and otherwise, it is determined that the engine 10 is in operation. Then, if low idle rotation speed Ne _la than the engine rotational speed Ne is stored in the storage unit 31, the engine 10 is adapted to determined to be in the low idle state.

Further, the determination unit 32 determines whether or not the pilot circuit is in a locked state based on the lock signal input from the hydraulic lock switch 51, that is, whether or not the hydraulic excavator 1 is not working because all operations of the hydraulic system are stopped. It comes to judge.
Further, the determination unit 32 determines whether or not there is a restart request based on the key ST signal input from the key switch 52. That is, if a key ST signal is input from the key switch 52, it is determined that there is a restart request.

The control unit 33 is a controller that transmits a command to the fuel injection device 19 based on the determination result of the determination unit 32 and controls the rotational speed Ne of the engine 10, and the cooling water temperature Tw detected by the cooling water temperature sensor 41. When the oil temperature To detected by the oil temperature sensor 42 is within the specified range and the hydraulic excavator 1 is not working for a predetermined time, an engine stop command is transmitted to the fuel injection device 19. When the fuel injection device 19 stops the fuel injection, the engine speed Ne is set to 0 rpm, and the engine stop function for stopping the engine 10 is executed. Further, when the engine 10 is stopped and the key ST signal is input from the key switch 52, a low idle command is transmitted to the fuel injection device 19, and the fuel injection device 19 injects appropriate fuel. It is configured to execute an engine restart function for the engine speed Ne to restart the engine 10 to the low idle speed Ne _la. Further, when the engine is in a low idle state and the operation lever 14 is operated, a return command is transmitted to the fuel injection device 19, and the fuel injection device 19 injects an appropriate fuel, thereby accelerating the engine 10. The engine speed is restored to the speed set by the dial 53, and the engine speed return function is performed to bring the engine 10 into a state where normal work is possible.

The display unit 34 is a controller that displays the current state of the engine 10 (for example, “idling stop” or “low idle”) on the monitor 54 based on the determination result of the determination unit 32.
The controller 30 configured as described above repeats the following flow at a predetermined cycle.

  That is, as shown in FIG. 3, in step A <b> 10, the determination unit 32 outputs the coolant temperature Tw output from the coolant temperature sensor 41, the oil temperature To output from the oil temperature sensor 42, and the engine speed sensor 44. The engine speed Ne, the lock signal output from the hydraulic lock switch 51, and the lever signal output from the lever sensor 43 are read, and the control unit 33 sets the accelerator dial 53 output from the accelerator dial 53. The value is read.

  In step A20, the determination unit 32 determines whether or not the engine 10 is operating based on the read engine speed Ne. Here, if the read engine speed Ne is not 0 rpm, it is determined that the engine 10 is operating. If it is determined that the engine is operating, the process proceeds to step A30, and if it is determined that the engine is not operating, the process proceeds to step A40.

In step A30, the subsequent flow is shifted to the engine operation mode task.
In Step A40, the subsequent flow is shifted to the engine pause mode task.
As shown in FIG. 4, in the engine operation mode task, in step B10, the determination unit 32 determines whether the hydraulic lock switch 51 is in a locked state, that is, whether the read hydraulic lock signal is ON. Determined. If it is determined that the hydraulic lock signal is ON, the process proceeds to step B20, and if it is determined that the hydraulic lock signal is OFF, the process proceeds to step B80.

In step B <b> 20, the determination unit 32 determines whether or not the read oil temperature To is within the specified range stored in the storage unit 31. If it is determined that the oil temperature To is within the specified range, the process proceeds to step B30, and if not, the process proceeds to step B40.
In step B30, the determination unit 32 determines whether or not the read cooling water temperature Tw is within a specified range. If it is determined that the coolant temperature Tw is within the specified range, the process proceeds to step B50, and if not, the process proceeds to step B40.

In step B40, the count of the timer built in the controller 30 is reset. Then, the engine operation mode task flow ends.
In step B50, the timer counts. Then, the process proceeds to Step B60.
In Step B60, when the time counted by the timer reaches the specified time, the process proceeds to Step B70. Otherwise, the engine operation mode task flow ends.

  In step B70, the engine stop function for stopping the engine 10 after the engine speed Ne is gradually lowered is executed by the controller 33. Then, the engine operation mode task flow ends. The engine stop function in step B70 is a so-called idling stop (temporary stop). That is, in steps B20 to B70, idling stop condition determination and idling stop are performed.

In step B80, the determination unit 32 determines whether or not the engine speed Ne is in a low idle state. Here, if the read engine rotational speed Ne is low idle rotation speed Ne _la below previously stored in the storage unit 73 in the storage unit _{31 (0 <Ne ≦ Ne la} ), when the engine 10 is low idle It comes to judge. If it is determined that the engine is in the low idle state, the process proceeds to step B90; otherwise, the flow of the engine operation mode task is terminated.

In step B90, the determination unit 32 determines whether the operation lever 14 is operated, that is, whether the read lever signal is ON. If the lever signal is ON, it is determined that there is a work request and the process proceeds to step B100. Otherwise, the flow of the engine operation mode task is ended.
In step B100, the controller 33 executes an engine speed return function for returning the engine speed Ne to the engine speed Ne corresponding to the read setting value of the accelerator dial 54. Then, the engine operation mode task flow ends.

That is, in steps B80 to B100, an engine speed return function is executed that returns the low idle state to the normal state when there is a work request.
As shown in FIG. 5, in the engine pause mode task, in step C <b> 10, the determination unit 32 determines whether the hydraulic lock switch 51 is ON. If the hydraulic lock switch 51 is ON, the process proceeds to Step C20, and if not, the process proceeds to Step C30.

In step C20, the determination unit 32 determines whether a key ST signal is input from the key switch 52, that is, whether the key switch 52 is turned to the ST position. If the key switch 52 is turned to the ST position, the process proceeds to Step C40, and if not, the process proceeds to Step C30.
In step C <b> 30, the display unit 34 displays characters “idling stop” on the monitor 54. Then, the engine pause mode task flow is terminated.

In step C40, the control unit 32 executes an engine restart function that restarts the engine 10 to bring the engine into a low idle state. Then, the process proceeds to Step C50.
In step C50, the display unit 34 displays the characters “low idle” on the monitor 54. Then, the engine pause mode task flow is terminated.

<Action and effect>
The engine control device for a work machine according to an embodiment of the present invention is configured as described above, and thus has the following operations and effects.
First, when the engine 10 is stopped and the hydraulic lock switch 51 is in the ON position, when the operator inserts the ignition key into the key cylinder and turns the key switch 52 to the ON position, power is supplied from the power source to the controller 30 and electrical components. For example, an illumination lamp or the like can be turned on.

  Next, when the key switch 52 is further rotated to the ST position, a key ST signal is transmitted from the key switch 52 to the controller 30, the controller 30 sends a command to the fuel injection device 19, and the fuel injection device 19 appropriately changes the fuel. The fuel is injected toward the engine 10 by controlling the injection amount, and the engine 10 is started.

As a result, the engine 10 enters an operating state, the main hydraulic pump 11 and the pilot pump 12 are driven by the engine 10, and the hydraulic excavator 1 can perform a desired operation by operating the operation lever 14. Note that the position of the key switch 52 automatically returns from the ST position to the ON position.
Here, when the operator keeps the hydraulic lock switch 51 in the cab 8 ON, the controller 30 continues when the coolant temperature Tw is within the specified range and the oil temperature To is within the specified range for a predetermined time. Gradually decreases the engine speed Ne and stops the engine 10. Therefore, when it is not necessary to operate the engine, such as when the excavator 1 is not operating for a predetermined time, the engine 10 can be stopped to save energy.

  At the same time, the engine 10 is stopped when the cooling water temperature Tw and the oil temperature To are within the specified ranges. Therefore, when the engine 10 is restarted after being temporarily stopped, the engine 10 is operated without being sufficiently warmed up or close to overheating. Driving in a state can be prevented. Therefore, the engine 10 can be restarted in a good state without taking time to resume the operation or overheating.

Further, when the key switch 52 is turned to the ST position by the operator while the engine 10 is stopped (temporarily stopped), the engine 10 is restarted. Here, since the engine 10 is restarted after the engine 10 is restarted, the engine 10 can be prevented from abruptly rising at the time of restart and the burden on the engine 10 can be reduced.
Further, when the operator operates the operation lever 14 while the engine 10 is operating in the low idle state, it is determined that there is an operation request (running request, turning request, and work request), and the engine speed is set by the accelerator dial 53. Since it returns to several Ne, when there is no work request, the work can be resumed quickly while saving energy in the low idle state.

  Furthermore, since the determination unit 32 of the controller 30 determines that the hydraulic excavator 1 is not operating when the hydraulic lock switch 51 is in the ON state, it can reliably grasp the state where the hydraulic excavator 1 is not operating. Can do. Further, since the engine 10 is stopped in a state where the operation of the hydraulic excavator 1 is locked, it is possible to prevent the hydraulic excavator 1 from operating due to an erroneous operation when the engine 10 is about to stop.

[Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the meaning of this invention.
For example, in the above-described embodiment, the determination unit 32 of the controller 30 determines that the excavator 1 is not working when the hydraulic lock switch 51 is in the ON state. For example, when the operation lever 14 is not operated at all, that is, when the lever signal is not output from the lever sensor 43, the excavator 1 is in operation. You may make it determine with it being in the state which is not. Alternatively, a load sensor that detects a load applied to the hydraulic excavator 1 and outputs a load signal to the controller 30 when there is a load, and the determination unit 32 is in a state where no load signal is output from the load sensor. It may be determined that the excavator 1 is not working. Note that even when such a lever sensor 43 or a load sensor determines that the hydraulic excavator 1 is not working, it is one of the condition determinations that the hydraulic lock switch 51 is in an ON state. It is preferable.

  Further, in the above-described embodiment, the hydraulic lock switch 51 is a switch for creating a state in which the excavator 1 cannot work, and the engine stop function is not effective unless the hydraulic lock switch 51 is in the ON state. However, in addition to the hydraulic lock switch 51, a lock switch that is turned ON / OFF by the operator may be provided simply for switching between enabling and disabling the engine stop function of the controller 30. Also in this case, since the engine stop function is effective only when the lock switch is turned ON by the operator, the controller 30 can execute the engine stop function according to the operator's intention. There is an advantage that the stop of the prepared engine 10 can be prevented.

Further, in the above-described embodiment, the engine 10 is restarted when the key switch 52 is turned to the ST position while the engine 10 is temporarily stopped. The engine 10 may be restarted when the restart switch is turned on during the 10 pause.
In the above-described embodiment, the case where the engine control device of the present invention is applied to the hydraulic excavator 1 has been described. However, the engine control device of the present invention can be appropriately modified to other work machines such as a bulldozer and a crane. It is possible to apply.

It is a schematic block diagram of the engine control apparatus of the working machine which concerns on one Embodiment of this invention. 1 is a perspective view of a hydraulic excavator equipped with an engine control device for a work machine according to an embodiment of the present invention. It is a flowchart which the engine control apparatus of the working machine which concerns on one Embodiment of this invention performs. FIG. 4 is a flowchart executed by the engine control device for a work machine according to an embodiment of the present invention, and shows the engine operation mode task of FIG. 3. FIG. 4 is a flowchart performed by the engine control device for a work machine according to an embodiment of the present invention, and shows the engine pause mode task of FIG. 3.

Explanation of symbols

1 Excavator (work machine)
2 Lower traveling body 3 Upper turning body 4 Boom 5 Arm 6 Bucket 7 Working device 8 Cab 10 Engine (internal combustion engine)
11 Main hydraulic pump (hydraulic pump)
DESCRIPTION OF SYMBOLS 12 Pilot pump 13 Control valve 14 Operation lever 14a Remote control valve 15 Radiator 16 Oil cooler 17 Cooling fan 18 Hydraulic oil tank 19 Fuel injection apparatus 21 Motor for driving (actuator)
22 Rotating motor (actuator)
23 Boom cylinder (actuator)
24 Arm cylinder (actuator)
25 Bucket cylinder (actuator)
30 controller (engine control means)
Reference Signs List 31 Storage Unit 32 Determination Unit 33 Control Unit 34 Display Unit 41 Cooling Water Temperature Sensor 42 Oil Temperature Sensor 43 Lever Sensor 44 Engine Speed Sensor 51 Hydraulic Lock Switch (Lock Switch)
52 Key switch (restart switch)
53 Accel dial 54 Monitor 55 Bypass valve

Claims (2)

An engine that is a drive source of the work machine;
A cooling water temperature sensor for detecting the temperature of cooling water for cooling the engine;
An oil temperature sensor for detecting the temperature of hydraulic oil for operating the work machine;
When the temperature of the cooling water detected by the cooling water temperature sensor and the temperature of the hydraulic oil detected by the oil temperature sensor are within a predetermined range, the state in which the work machine is not working is determined for a predetermined time. An engine control device for a work machine, comprising engine control means having an engine stop function for stopping the engine when the operation is continued. In order to enable the engine stop function of the engine control means, a lock switch that is turned ON / OFF by an operator is provided,
The lock switch enables the engine stop function when being turned ON by an operator and disables the engine stop function when being turned OFF by an operator. Engine control device for work machines.

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