JP2006022701A - Engine control device in construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To limit automatic engine stop until engine temperature and operating oil temperature is lowered to temperatures set beforehand or below when providing an automatic engine stop mechanism in a hydraulic excavator 1 for automatically stopping an engine if an operation controller is not operated for a predetermined set time or more. <P>SOLUTION: The device is constructed so that an engine room temperature measuring sensor 18 is provided in an engine room 6 and the automatic stop of the engine at the time of detecting no operation can be limited until a difference between a measured temperature in the room and outside air temperature becomes a temperature set beforehand or below. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of engine control devices in construction machines such as hydraulic excavators.

Today, as part of protecting the natural environment and preventing global warming, construction machinery such as hydraulic excavators have been proposed to reduce fuel consumption, and as one of them, the engine is automatically driven when not working. Attempts have been made to stop. And as such an attempt, the operator locks the hydraulic lock switch (also expressed as a lock lever switch, gate lock switch, etc., hereinafter the same) to stop the operation and exit the operation cockpit, that is, the hydraulic lock state If the predetermined timer time elapses, the engine is automatically stopped (for example, Patent Documents 1, 2, and 3).
JP 2000-96627 A JP 2001-41069 A JP 2003-307142 A

  By the way, when the construction machine performs a heavy load work or works in a high temperature atmosphere, the temperature of the cooling water or hydraulic oil may be high. It is necessary to lower the engine speed to a standby engine speed (for example, idling engine speed) and lower the temperature of the cooling water or hydraulic oil before stopping the engine. However, the conventional ones ignore this, and even if the temperature of the cooling water or hydraulic oil is high, the engine is stopped based on the elapse of a predetermined timer time after the hydraulic lock switch is turned on. Therefore, there is a problem that it is easy to induce a failure and the life of the construction machine is shortened, and there is a problem to be solved by the present invention.

The present invention has been created in view of the above circumstances and has been created to solve these problems. The invention of claim 1 includes a hydraulic pump that drives an engine as a drive source, and the hydraulic pump. In the construction machine configured to perform the operation of the hydraulic actuator that receives the hydraulic oil supplied from the operation means based on the operation of the operation means, when the operation means is not operated for a preset time period In providing a control unit for controlling the engine to automatically stop, the control unit performs the automatic engine stop after determining that the engine temperature is equal to or lower than a preset temperature. An engine control apparatus for a construction machine, characterized in that limiting means for limiting is provided.
According to a second aspect of the present invention, in the first aspect, in addition to the determination that the engine temperature is equal to or lower than a first preset temperature set in advance, the limiting means further includes a second hydraulic oil temperature set in advance. An engine control apparatus for a construction machine, wherein the engine is set to automatically stop when it is determined that the temperature is lower than a set temperature.
According to a third aspect of the present invention, in the second aspect, the judgment that the engine temperature and the hydraulic oil temperature are lower than the first and second preset temperatures set in advance is the difference between the temperature in the engine room and the outside air temperature. An engine control apparatus for a construction machine, characterized in that is determined by whether or not the temperature is equal to or lower than a preset temperature.
According to a fourth aspect of the present invention, in the second aspect of the present invention, the determination that the engine temperature and the hydraulic oil temperature are equal to or lower than the first and second set temperatures set in advance is a temperature set in advance in the engine room. An engine control apparatus for a construction machine, characterized in that it is determined by whether or not:
According to a fifth aspect of the present invention, in the first or second aspect, the determination that the engine temperature is equal to or lower than a first preset temperature that is preset is whether or not the engine coolant temperature is equal to or lower than a preset temperature. The engine control apparatus in the construction machine is characterized by the above.
According to a sixth aspect of the present invention, in the second aspect, the determination that the hydraulic oil tank is equal to or lower than a second preset temperature that is preset is that the hydraulic oil temperature in the hydraulic oil tank is equal to or lower than a preset temperature. This is a control device for an engine in a construction machine.

According to the first aspect of the present invention, the engine is automatically stopped when the operation of the operation unit is not performed by the operation unit for a preset time set in advance. Thus, the engine-related members can be protected.
According to the invention of claim 2, not only the engine temperature but also the hydraulic oil temperature is preliminarily determined when the operation of the operation unit is not operated by the operation unit for a preset time. The temperature is limited until the temperature is lower than the set temperature, so that effective protection can be achieved not only for the engine but also for the hydraulic member.
According to the invention of claim 3 or 4, since the cooling air supplied to the engine room has passed through a radiator that cools the cooling water and an oil cooler that cools the hydraulic oil, the temperature of both is detected by one temperature detection. As a result, the temperature sensor can be shared.
By setting it as invention of Claim 5, an engine temperature can be measured by measuring a cooling water temperature.
By setting it as invention of Claim 6, the hydraulic oil temperature can be measured by measuring the temperature of the hydraulic oil tank.

  Next, embodiments of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 denotes a hydraulic excavator which is an example of a construction machine. The hydraulic excavator 1 includes a crawler-type lower traveling body 2, an upper revolving body 3 which is swingably provided on the lower traveling body 2, and the upper revolving body. A bucket 4 provided as a work attachment on the body 3, a cab-type driving cockpit 5, arranged behind the driving cockpit 5, an engine room 6 in which an engine 6 a is installed, and a side of the driving cockpit 5. It is conventional that all the components are configured using various member devices such as the fuel tank 7 and the hydraulic oil tank 8.

  The operation cockpit 5 includes an operation lever, an operation pedal, an operation tool 12 such as an operation switch, and an engine automatic stop provided for operating various hydraulic actuators 11 such as a starter switch 9, a hydraulic lock lever 10, and a bucket cylinder 11a. An automatic stop selection switch 13 for selecting whether or not to perform is provided. The hydraulic lock lever 10 stands up so as not to get in the way when the operator gets into and out of the driving cockpit 5, and falls down so as to get in the way of getting on and off when sitting in the driving cockpit 5. A hydraulic lock switch 14 for detecting the ups and downs of 10 is provided. When the hydraulic lock switch 14 is ON, that is, when the hydraulic lock lever 10 is standing up, the hydraulic valve is in a locked state, and the control valve 15 is not switched even if the operation tool 12 is operated. 11 is prohibited, and only when the hydraulic lock lever 10 is lying down and the hydraulic lock switch 14 is OFF, when the operation tool 12 is operated, a control command is output to the control valve 15 and the hydraulic actuator 11 operations are executed.

Next, the automatic stop control of the first embodiment of the engine 6a in which the present invention is implemented will be described with reference to the block circuit diagram shown in FIG. 3 and the flowchart shown in FIG. The engine room 6 is set to automatically stop the engine based on the temperature of the engine room 6. The engine room 6 includes a radiator 6b for cooling the cooling water of the engine 6a and an oil cooler 6c for cooling the working oil. Since the passing cooling air enters, by measuring the temperature of the cooling air that has entered the engine room 6, the temperatures of the cooling water and the hydraulic oil are simultaneously measured using the engine room temperature measuring sensor 18 as will be described later. Take advantage of what you can do.
In the drawing, reference numeral 16 denotes a control unit configured by using electronic and electrical equipment such as a microcomputer, which executes various controls of the hydraulic excavator, but here is related to the automatic stop control of the engine 6a. The description will be limited to. In addition to the operation tool operation detection sensor 17 for detecting that the starter switch 9, the automatic stop selection switch 13, the hydraulic lock switch 14, and the operation tool 12 have been operated, the control unit 16 includes the temperature in the engine room 6. An engine room temperature measuring sensor 18 for measuring and an outside temperature measuring sensor 19 for measuring the outside air temperature (the sensor 19 may be a dedicated one, but the cab type is provided with an air conditioning device (air conditioner). In this case, an outside air temperature measurement sensor provided in the air conditioner can be used), and signals from these switches and sensors are input. And the control part 16 performs a required calculation based on these input signals, and while outputting a drive control command with respect to the engine 6a, it is further attached to various electrical components (for example, an air conditioner and an audio equipment) mounted in the fuselage. A control command is output to a power switch 20 for power supply for supplying power, a main power switch 21 for turning on and off the main power, and a notification means 22 such as a speaker.

  When the starter switch 9 is turned on to perform initial setting for reading necessary information, and when the engine 6a is started and engine drive control is started, the control unit 16 detects the operation from the operation tool operation detection sensor 17. If it is determined whether or not a signal has been input, and YES is determined as having been input, the engine speed is set in advance for the engine 6a (for example, the accelerator dial set speed or the speed at full throttle drive). ) Is output to return to the determination state as to whether or not an operation detection signal is input. At this time, drive control of the engine 6 is executed so as to achieve the working rotational speed. On the other hand, if no operation signal is input and NO is determined as being in the no-operation state, whether or not the no-operation state has continued until a preset first timer time T1 has elapsed. If the determination is made and NO is determined that the first timer time T1 has not elapsed, a drive control command is output to the engine 6a so that the engine speed is equal to the working rotational speed. On the other hand, if YES is determined that the first timer time T1 has elapsed, it is further determined whether or not the automatic stop selection switch 13 is ON, and the automatic stop selection switch 13 is OFF (automatic stop control). If NO is determined, the drive control command is output to the engine 6a so as to have a preset standby rotational speed (for example, the rotational speed during low idling). As a result, the engine 6a is switched from driving at the working rotational speed to driving at the standby rotational speed, and the driving is executed.

  On the other hand, if the automatic stop selection switch 13 is ON, that is, if a determination of YES is made assuming that automatic stop is selected, it is further determined whether or not the hydraulic lock switch 14 is ON. If the determination is NO, assuming that the switch 14 is OFF, that is, the hydraulic lock lever 10 is in a state of obstructing the operator to get on and off, the standby drive control command is output. On the other hand, if the hydraulic lock switch 14 is OFF, that is, if a determination of YES is made assuming that the hydraulic lock lever 10 does not interfere with getting on and off the operator, the automatic stop selection switch 13 is ON and the hydraulic lock switch It is determined whether or not the state in which 14 is ON continues for a preset second timer time T2. Then, if the determination that the automatic stop selection switch 13 and the hydraulic lock switch 14 are ON is not determined that the second timer time T2 has not yet elapsed, the output of the standby drive control command is continued. Wait for the elapse of the second timer time T2 in the state.

  On the other hand, if YES is determined that the second timer time T2 has elapsed, the sensor values X1 and X2 of the engine room temperature measuring sensor 18 and the outside air temperature measuring sensor 19 are read, and the measured temperature X1 of the engine room is read. It is determined whether or not the measured temperature difference (X1−X2) from the outside air measured temperature X2 is equal to or smaller than a preset temperature difference X (X1−X2 ≦ X). If not, that is, the measured temperature difference is set. If NO is determined as being higher than the temperature difference (X1-X2> X), the output of the standby drive control command is continued. On the other hand, if a determination of YES is made assuming that the measured temperature difference is equal to or less than the set temperature difference X, the control unit 16 causes the engine such as “stops the engine” to the notification means 22 exemplified by a speaker, a display, or the like. The output of the stop warning command is continuously output during the preset third timer time T3. When the third timer time T3 has elapsed, a stop command is output to the engine 6a and the power switch 20 for electrical components is supplied. An OFF command is output to the main power switch 21 after a preset fourth timer time T4 has elapsed.

  In the first embodiment of the present invention configured as described above, when the automatic stop selection switch 13 is turned ON and the automatic stop of the engine 6a is selected, the operator should leave the operation cockpit 5. The automatic stop of the engine 6a in the hydraulic lock state is performed when the temperature in the engine room 6 is high even after the second timer time T2 has elapsed since the hydraulic lock state, that is, in the present embodiment. When the measured temperature difference obtained by subtracting the outside air temperature X2 from the measured temperature X1 in the engine room is higher than the preset temperature difference X, the engine does not stop, and the engine 6a is at the standby rotational speed. It will continue to drive, and the measured temperature difference will be lower than the set temperature difference X, and there will be no problem even if the engine is stopped. Automatic engine stop to the matter is executed.

  As described above, in the first embodiment in which the present invention is implemented, the automatic engine stop waits for the temperature in the engine room 6 to drop to a temperature at which no problem occurs even if the engine is stopped. When executed, that is, in a state where the temperature in the engine room 6 is high, the automatic stop of the engine 6a is limited even when the operation tool 12 is not operated for a predetermined time. In addition, the engine 6a does not automatically stop when the temperature in the engine room 6 is high, and as a result, the engine 6a related parts and hydraulic parts are broken or the life of the body is shortened. You can avoid that.

  In this case, the engine room 6 utilizes the fact that cooling air that has passed through the radiator 6b for cooling the engine coolant and the oil cooler 6c for cooling the working oil enters, and the temperature of the cooling air By measuring, it is possible to measure the temperature of both, and two sets of temperature measurement sensors are not required unlike those for each dedicated temperature measurement, and one set is sufficient, so the number of parts Reduction can be achieved. Of course, the present invention can also be implemented using dedicated temperature measuring sensors as will be described later.

  Moreover, in the said embodiment, since the criterion is whether or not the difference between the measured temperature and the outside air temperature is equal to or lower than a preset temperature, the temperature drop is slow as when working in a high temperature region. It is effective in some cases.

  In the present invention, as in the first embodiment, the measured temperature difference obtained by subtracting the outside air temperature X2 from the temperature X1 in the engine room is lower than the preset temperature difference X. Of course, the engine 6a is not limited to the automatic stop, and the engine is automatically stopped after the measured temperature in the engine room is lower than a preset temperature. You can also Furthermore, the engine is automatically stopped after waiting for the temperature of the cooling water for cooling the engine to be lower than the set temperature or waiting for the temperature of the hydraulic oil to be lower than the preset temperature. It can also be configured.

  Furthermore, as in the second embodiment shown in FIGS. 5 and 6, the engine is automatically stopped when the temperature of the cooling water and the temperature of the hydraulic oil are both lower than the set temperatures. However, this can be implemented, and this will be described. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and different points are mainly described. In the block circuit diagram shown in FIG. 5, the control unit 16 replaces the engine room temperature measuring sensor 18 and the outside air temperature measuring sensor 19 with detection signals from the coolant temperature detecting sensor 23 and the hydraulic oil temperature detecting sensor 24. Is to enter.

  Then, when it is determined that the ON state of the automatic stop selection switch 13 and the ON state of the hydraulic lock switch 14 are continued for the second timer time T2, the coolant temperature measurement sensor 23, the hydraulic oil temperature measurement The measured temperatures Y1 and Z1 of the sensor 24 are read, the read cooling water measured temperature Y1 is equal to or lower than a preset cooling water set temperature Y (Y1 ≦ Y), and the hydraulic oil measured temperature Z1 is preset. The automatic stop of the engine 6a is executed after it is determined that the hydraulic oil set temperature Z or lower (Z1 ≦ Z) is reached, that is, there is a limit to the automatic stop of the engine 6a until this state is reached. By doing in this way, not only the engine temperature but also the automatic stop of the engine 6 in a state where the hydraulic oil temperature is lowered is executed, not only the engine 6a, Mounting to various attractants or aircraft life failure of hydraulic equipment will be possible to avoid or shorten.

1 is an overall side view of a hydraulic excavator. It is a top view of a hydraulic excavator. It is a block circuit diagram which shows the control system of 1st embodiment. It is a flowchart figure of the control system. It is a block circuit diagram which shows the control system of 2nd embodiment. It is a flowchart figure of the control system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 6 Engine room 6a Engine 13 Automatic stop selection switch 14 Hydraulic lock switch 16 Control part 17 Operation tool operation detection sensor 18 Engine room temperature measurement sensor 19 Outside air temperature measurement sensor

Claims (6)

  In a construction machine comprising a hydraulic pump that drives an engine as a drive source and configured to perform operation of a hydraulic actuator that receives hydraulic oil supplied from the hydraulic pump based on operation of the operation means, the operation means In the case of providing a control unit that controls to automatically stop the engine when there is no preset operation for a preset time, the engine temperature is set in advance in the control unit to execute the automatic stop of the engine. A control device for an engine in a construction machine, characterized in that limiting means for limiting the temperature to be performed after determining that the temperature is equal to or lower than a predetermined temperature is provided.   In the first aspect, in addition to determining that the engine temperature is equal to or lower than a first preset temperature set in advance, the restricting means further determines that the hydraulic oil temperature is equal to or lower than a second preset temperature set in advance. An engine control apparatus for a construction machine, which is set to execute an automatic engine stop when a determination is made.   In Claim 2, the judgment that the engine temperature and the hydraulic oil temperature are equal to or lower than the first and second preset temperatures that are set in advance is that the difference between the temperature in the engine room and the outside air temperature is equal to or lower than the preset temperature. A control device for an engine in a construction machine, characterized in that it is determined by whether or not.   In claim 2, whether the engine temperature and the hydraulic oil temperature are lower than the first and second preset temperatures set in advance is determined by whether or not the temperature in the engine room is lower than the preset temperature. A control device for an engine in a construction machine, characterized by being judged.   In Claim 1 or 2, the determination that the engine temperature is equal to or lower than a first preset temperature is determined based on whether or not the engine coolant temperature is equal to or lower than a preset temperature. An engine control device for a construction machine.   In claim 2, the determination that the hydraulic oil tank is equal to or lower than a preset second set temperature is determined based on whether or not the hydraulic oil temperature in the hydraulic oil tank is equal to or lower than a preset temperature. An engine control device for a construction machine.

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