JP2008144626A - Abnormality determining device for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine the operation abnormality of an engine due to the use of fuel other than a regular product. <P>SOLUTION: This abnormality determining device for a construction machine comprises the engine 10 driving a hydraulic pump 11 for work; a rotating speed instructing means 21 instructing the target rotating speed NT of the engine 10; a rotating speed detecting means 22 detecting the actual rotating speed NR of the engine 10; a rotating speed control means 20 controlling engine speed so that the actual rotating speed NR is the target rotating speed NT; a state detecting means 16 detecting the constant state of load applied to the engine 10; and an abnormality determining means 20 determining the operation abnormality of the engine 10 based on deviation ΔN between the target rotating speed NT instructed by the rotating speed instructing means 21 and the actual rotating speed NR detected by the rotating speed detecting means 22 when the constant state of load is detected by the state detecting means 16. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an abnormality determination device for a construction machine that determines an abnormal operation of an engine mounted on the construction machine.

  An apparatus is known in which an abnormality of a fuel injection system is determined based on an oxygen concentration in exhaust gas from a diesel engine (see, for example, Patent Document 1).

Japanese Patent No. 3721671

  By the way, diesel engines use light oil as fuel. For example, when a construction machine is rented, the customer uses kerosene or heavy oil, which is cheaper than light oil, as the fuel without the rental agent's knowledge. There is. Since kerosene has poor lubricity compared to light oil, wear of the fuel injection system occurs, and when heavy oil is used, the nozzle of the fuel injection system may be clogged. When the engine is driven using fuel other than the regular product as described above, even if the engine fuel injection system itself is not abnormal, the operation of the engine becomes abnormal, and the engine life is shortened.

An abnormality determination device for a construction machine according to the present invention includes an engine that drives a working hydraulic pump, a rotational speed command means that commands a target rotational speed of the engine, a rotational speed detection means that detects an actual rotational speed of the engine, A rotation speed control means for controlling the engine rotation speed so that the rotation speed becomes the target rotation speed, a state detection means for detecting a constant load state where the load acting on the engine is constant, and a constant load state by the state detection means Is detected, an abnormality determining means for determining an engine operation abnormality based on a deviation between the target rotational speed commanded by the rotational speed commanding means and the actual rotational speed detected by the rotational speed detecting means. Features.
If the state where the deviation between the target rotational speed and the actual rotational speed is equal to or greater than a predetermined value continues for a predetermined time, it can be determined that the engine operation is abnormal.
Temperature detection means for detecting the temperature of a substance that affects the engine speed increase characteristic, and at least one of the predetermined value and the predetermined time is set to a value corresponding to the temperature detected by the temperature detection means; You can also.
When the abnormality determination means determines that the engine operation is abnormal, the information processing apparatus may further include a storage means for storing information corresponding to the abnormal operation.
If the engine operation is determined to be abnormal by the abnormality determination unit, a transmission unit that transmits information corresponding to the abnormal operation to the base station can be further provided.

  According to the present invention, the engine operation abnormality is determined based on the deviation between the target engine speed and the actual engine speed in a state where the load acting on the engine is constant. It is possible to determine abnormal operation when the engine is driven by using it.

Hereinafter, an embodiment of an abnormality determination device according to the present invention will be described with reference to FIGS.
FIG. 1 is a side view of a hydraulic excavator equipped with the abnormality determination device according to the present embodiment. The hydraulic excavator includes a traveling body 1, a revolving body 2 provided on the traveling body 1 so as to be turnable, and a boom 3 A, an arm 3 B, and a bucket 3 C that are rotatably attached to the turning body 2. And have. Boom 3A, arm 3B, and bucket 3C are driven by hydraulic cylinders 30A, 30B, and 30C, respectively. A driver's cab 4 is provided at the front of the revolving unit 2, and an engine room 5 is provided at the rear thereof. A counterweight 6 is attached to the rear end of the revolving unit 2. A gate lock lever 7 that can be operated between a release position protruding from the boarding / alighting path and a lock position retracted from the boarding / alighting path is provided at the entrance of the cab 4.

  FIG. 2 is a diagram showing an example of a working hydraulic circuit, and here, a driving circuit for the hydraulic cylinder 30A is shown. The driving circuits for the other hydraulic cylinders 30B and 30C are the same as those in FIG. Pressure oil from the hydraulic pump 11 driven by the engine 10 is guided to the hydraulic cylinder 30 </ b> A via the direction control valve 12. Pilot pressure from the hydraulic pump 14 corresponding to the operation amount of the operation lever 13 acts on the direction control valve 12, and the hydraulic pressure switching valve 12 is switched according to the operation amount of the operation lever 13.

  A lock valve 15 operated by the gate lock lever 7 is provided downstream of the hydraulic pump 7. The lock valve 15 is switched to the position A when the gate lock lever 7 is operated to the release position, and is switched to the position B when it is operated to the lock position. When the lock valve 15 is switched to the position A, the pilot pressure action from the hydraulic pump 14 to the control valve 12 is permitted, and when the lock valve 15 is switched to the position B, the pilot pressure action is prohibited. The switching state of the lock valve 15 is detected by a pressure sensor 16 provided downstream of the lock valve 15. When the lock valve 15 is switched to the position B, the pressure sensor 16 outputs a gate lock signal.

  The engine 10 is a so-called common rail type diesel engine, a pump that pumps fuel at a high pressure, a rail that stores high-pressure fuel sent from the pump, an injector that injects high-pressure fuel, and an injection amount of fuel. It has the engine controller 20 (FIG. 3) etc. which control a time. Since the engine 10 injects fuel at a high pressure, combustion efficiency is high, NOx in the exhaust gas is reduced, and emission is improved. A radiator 17 and a heater 18 are provided in the engine cooling water circulation path.

  The engine 10 uses light oil as regular fuel, and lubricates the injector with fuel. For this reason, if inexpensive kerosene or heavy oil is used as fuel, the lubricity of kerosene or heavy oil is worse than that of light oil, so that the lubrication part is worn and the engine life is shortened. In addition, combustion efficiency also deteriorates, making it difficult to improve emissions. Therefore, in the present embodiment, it is determined whether or not the engine 10 is operating abnormally by using kerosene or heavy oil as fuel, and the determination result is notified.

  FIG. 3 is a block diagram showing a system configuration of the abnormality determination device according to the present embodiment. The hydraulic excavator includes an engine controller 20, a main controller 30, a monitor controller 40, and an information controller 50, and the controllers 20 to 50 are connected to each other via a CAN communication line 25. The engine controller 20 includes a rotation speed setting device (for example, a rotation speed setting dial) 21 that sets a target rotation speed NT of the engine 10 by an operation of a worker, and a rotation speed detector 22 that detects the actual rotation speed NR of the engine 10. And are connected. A pressure sensor 16 and a communication device 31 are connected to the main controller 30. A display device 41 is connected to the monitor controller 40, and a storage device 51 such as an EEPROM is connected to the information controller 50. The system configuration of the abnormality determination device is not limited to this, and the functions of the controllers 20 to 50 may be integrated into a single controller, for example.

  The engine controller 20 includes an arithmetic processing unit having a CPU, ROM, RAM, and other peripheral circuits, and controls the fuel injection amount and timing so that the actual rotational speed NR becomes the target rotational speed NT. That is, the target rotational speed NT and the actual rotational speed NR are compared, and if NT> NR, the fuel injection amount is increased by a predetermined amount ΔA, and if NT <NR, the process of decreasing the predetermined amount ΔA is repeatedly performed. The number NR is brought close to the target rotational speed NT.

  Here, the predetermined amount ΔA is a value set on the assumption that regular fuel (light oil) is used. If the engine 10 is operated with a constant load using regular fuel, the increase characteristic of the engine speed is For example, it becomes as shown by the characteristic f1 in FIG. That is, the deviation ΔN between the target rotational speed NT and the actual rotational speed NR becomes equal to or less than the predetermined value ΔNa at time t1 from the engine start, and the actual rotational speed NR quickly approaches the target rotational speed NT. On the other hand, when the engine 10 is operated using fuel other than light oil (heavy oil or kerosene), the deviation ΔN of the engine speed becomes equal to or less than a predetermined value ΔNa at time t2 (> t1) from the start of the engine as shown by the characteristic f2. More time is required for the actual rotational speed NR to approach the target rotational speed NT. Focusing on this point, the abnormal operation determination of the engine 10 is performed in the present embodiment.

  The main controller 30 includes an arithmetic processing unit having a CPU, ROM, RAM, and other peripheral circuits. FIG. 5 is a flowchart illustrating an example of processing executed by a program installed in the main controller 30. This flowchart starts when the engine 10 is started by turning on an engine key switch, for example. In step S1, the target rotational speed NT is read from the engine controller 20 via the CAN communication line 25, and in step S2, the actual rotational speed NR is read from the engine controller 20.

  In step S3, it is determined whether or not the gate lock signal is output from the pressure sensor 16, that is, whether or not the work is prohibited. If step S3 is affirmed, the process proceeds to step S4, where the actual engine speed NR is subtracted from the target engine speed NT to calculate the engine speed deviation ΔN. In step S5, it is determined whether or not the deviation ΔN is larger than a predetermined value ΔNa (FIG. 4). In step S6, the timer t is counted. On the other hand, if step S3 or step S5 is denied, the process proceeds to step S10 and the timer t is reset.

  In step S7, it is determined whether or not the timer t has counted a predetermined time ta. The predetermined time ta is a threshold value for determining whether or not the operation of the engine 10 is abnormal, and is set to a value between the times t1 and t2 in FIG. 4, for example. If step S7 is positive, the process proceeds to step S8, and if negative, the process returns. In step S <b> 8, an abnormality signal is output to the communication device 41 and an abnormality signal is also output to the monitor controller 40 and the information controller 50 via the CAN communication line 25.

  When an abnormal signal is output from the main controller 30, the communication device 31 transmits abnormal information corresponding to the abnormal signal to the remote base station via the communication antenna 32. The abnormality information transmitted from the communication device 31 includes, for example, the time when the abnormality occurred, the type of the hydraulic excavator, the number machine, the transition of the target rotational speed NT and the actual rotational speed NR of the engine 10, and the operation of the engine 10 thereby. Abnormality can be grasped at the base station. If the excavator is equipped with a self-position measuring device such as a GPS device, the position information may be included in the abnormality information and transmitted. The abnormality information may be transmitted every time an abnormality signal is output, or may be transmitted collectively after the work is completed.

  When an abnormal signal is output from the main controller 30, the monitor controller 40 displays alarm information corresponding to the abnormal signal on the display device (display monitor) 41 in the cab, for example, alarm information indicating that regular fuel is not used. To do. In addition to displaying alarm information, an alarm sound may be generated. As a result, it is possible to call the worker to stop using the wrong fuel.

  When an abnormal signal is output from the main controller 30, the information controller 50 stores abnormal information corresponding to the abnormal signal in a storage device 51 such as an EEPROM. The abnormality information stored in the storage device 51 includes, for example, the time when the abnormality occurred, the transition of the target rotational speed NT and the actual rotational speed NR of the engine 10, and the like. The abnormality information is included in the work history information, and other work history information is stored in the storage device 51. As a result, what kind of work has been performed can be analyzed later, and maintenance and the like can be appropriately performed based on the work history information.

  The above processing is preferably performed in a state where the target rotational speed NT is constant. For example, when the setting of the target rotational speed NT is changed, the timer is reset and the state of ΔN> ΔNa continues for a predetermined time ta. You may make it determine whether it was done.

  The operation of the abnormality determination device according to the present embodiment will be described more specifically. The abnormality determination of the engine 10 is performed in a state where the load acting on the engine 10 is constant, that is, in a state where the gate lock lever 7 is operated to the locked position and no work load acts on the engine 10 (non-working state). At this time, if the engine 10 is started using regular fuel, the deviation ΔN between the target rotational speed NT and the actual rotational speed NR becomes equal to or less than the predetermined value ΔNa before the predetermined time ta elapses. Is determined to be normal. In this state, the process of step S7 in FIG. 5 described above is denied, so that an engine abnormality signal is not output.

  On the other hand, when the engine 10 is started using fuel other than a regular product, the deviation ΔN between the target rotational speed NT and the actual rotational speed NR does not become equal to or less than the predetermined value ΔNa even when the predetermined time ta has elapsed. Ten operations are determined to be abnormal. In this state, an abnormality signal is output from the main controller 30 (step S8), and abnormality information is transmitted to the base station. For this reason, for example, when a hydraulic excavator is rented, the base station can know whether or not the hydraulic excavator is used using regular fuel, and to customers who use wrong fuel A warning can be given. Further, since the abnormality information is also stored in the storage device 51, the rental agent can grasp that the abnormality has occurred in the engine 10 when the hydraulic excavator is returned. Since the alarm information is displayed on the display device 41, it is possible to warn the worker not to use the wrong fuel.

According to the above embodiment, the following effects can be obtained.
(1) When the gate lock lever 7 is operated to the locked position, a deviation ΔN between the target rotational speed NT of the engine 10 and the actual rotational speed NR is calculated, and a state where the deviation ΔN is equal to or larger than a predetermined value ΔNa is a predetermined time. An abnormal signal is output when ta is continued. Thereby, it can be determined that there is an abnormality in the operation of the engine 10, and it is possible to suppress work using wrong fuel. As a result, the wear of the injector can be suppressed and the life of the engine 10 can be prevented from being reduced. Further, the combustion efficiency of the engine 10 is high, and the exhaust gas can be cleaned.

(2) When the gate lock lever 7 is operated to the locked position, that is, when the operation is prohibited, the abnormality determination is made, so that the engine speed changes due to the fluctuation of the work load acting on the engine 10 Therefore, it is possible to easily perform abnormality determination.
(3) When the engine speed deviation ΔN is equal to or greater than the predetermined value ΔNa continues for a predetermined time Δta, the operation of the engine 10 is determined to be abnormal. Can be determined appropriately.
(4) Since the abnormality determination of the engine 10 is performed based on the deviation ΔN of the engine speed, not only an abnormality caused by using a fuel other than a regular product but also an abnormality caused by using a fuel other than a normal engine oil, Other abnormalities that may increase the engine speed deviation ΔN, such as abnormalities caused by neglecting replacement or abnormalities caused by eye contact with the fuel filter, can also be determined.

(5) When the operation of the engine 10 is determined to be abnormal, the abnormality information is transmitted to the base station via the communication device 31. Therefore, when the hydraulic excavator is rented, the base station grasps whether there is an abnormality. It is possible to respond to an abnormal operation of the engine 10 at an early stage.
(6) When the operation of the engine 10 is determined to be abnormal, the work history information including the abnormality information is stored in the storage device 51, so that information useful for maintenance and the like is obtained.
(7) When the operation of the engine 10 is determined to be abnormal, the alarm information is displayed on the display device 41, so that the operator can be notified that an abnormality has occurred in the engine 10.

  In the above, the operation of the engine 10 is determined to be abnormal when the engine speed deviation ΔN is equal to or greater than the predetermined value ΔNa for a predetermined time Δta. However, the engine cooling water temperature or the outside air temperature is detected by the temperature detection means such as a temperature sensor. Or the like, and at least one of the predetermined value ΔNa and the predetermined time Δta may be changed according to the detected value of the engine coolant temperature or the outside air temperature. For example, the predetermined value ΔNa and the predetermined time Δta may be increased as the engine coolant temperature is lower or the outside air temperature is lower. This improves the accuracy of abnormality determination. Na and Δta may be changed in accordance with not only the engine cooling water temperature and the outside air temperature, but also the temperature of other substances that affect the engine speed increase characteristics.

  In the above-described embodiment, the target rotational speed NT is set by operating the rotational speed setter (rotational speed setting dial) 21 and the target rotational speed NT is set as the engine rotational speed command value. The rotational speed may be commanded by an operation or the like, and the configuration of the rotational speed command means is not limited to that described above. As long as the actual rotational speed NR of the engine 10 is detected, any configuration of the rotational speed detector 22 as the rotational speed detection means may be used. Although the fuel injection amount and the like are controlled by the engine controller 20 so that the actual rotational speed NR of the engine 10 becomes the target rotational speed NR, the configuration of the rotational speed control means is not limited to this. The engine 10 may not be a common rail type.

  In the above embodiment, when the operation of the gate lock lever 7 is detected by the pressure sensor 16 and the operation is prohibited by the operation of the gate lock lever 7, the abnormality determination of the engine 10 is performed. If the abnormality determination is performed in a state where the load acting on the power supply is constant, the operation is not necessarily prohibited, and the configuration of the state detection means is not limited to that described above. In this case, it is preferable that the target rotational speed NT is constant. When the engine speed deviation ΔN is equal to or greater than the predetermined value ΔNa continues for a predetermined time Δta, the main controller 30 determines that the operation of the engine 10 is abnormal. For example, depending on the magnitude of the deviation ΔN after the predetermined time The abnormality determination may be performed, and the configuration of the abnormality determination means is not limited to that described above.

  When it is determined that the operation of the engine 10 is abnormal, the abnormality information is stored in the storage device 51, but the storage means may have any configuration. When it is determined that the operation of the engine 10 is abnormal, the abnormality information is transmitted to the base station via the communication device 31. However, the transmission means may have any configuration. Abnormal information may not be transmitted. If it is determined that the operation of the engine 10 is abnormal, the operation (for example, the rotational speed) of the engine 10 may be limited to prevent a failure of the engine 10. The example in which the abnormality determination device is applied to a hydraulic excavator has been described above. However, the abnormality determination device can be similarly applied to other construction machines such as a wheeled hydraulic excavator. That is, the present invention is not limited to the abnormality determination device according to the embodiment as long as the features and functions of the present invention can be realized.

1 is a side view of a hydraulic excavator equipped with an abnormality determination device according to an embodiment of the present invention. The figure which shows an example of the hydraulic circuit for work. The block diagram which shows the system configuration | structure of the abnormality determination apparatus which concerns on embodiment of this invention. The figure which shows an example of the change of an actual rotation speed. The flowchart which shows an example of the process performed with the main controller of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 16 Pressure sensor 20 Engine controller 21 Rotation speed setting device 22 Rotation speed detector 30 Main controller 31 Communication apparatus 51 Memory | storage device

Claims (5)

An engine that drives a working hydraulic pump;
A speed command means for commanding a target engine speed;
A rotational speed detection means for detecting the actual rotational speed of the engine;
A rotational speed control means for controlling the engine rotational speed so that the actual rotational speed becomes the target rotational speed;
State detecting means for detecting a constant load state in which the load acting on the engine is constant;
When a constant load state is detected by the state detection means, an engine operation abnormality determination is made based on a deviation between the target rotational speed commanded by the rotational speed command means and the actual rotational speed detected by the rotational speed detection means. An abnormality determination device for a construction machine, comprising: In the construction machine abnormality determination device according to claim 1,
The abnormality determination means determines that the operation of the engine is abnormal when a deviation between the target rotational speed and the actual rotational speed is a predetermined value or more continues for a predetermined time. apparatus. The construction machine abnormality determination device according to claim 2,
Temperature detecting means for detecting the temperature of a substance that affects the increase characteristic of the engine speed,
At least one of the predetermined value and the predetermined time is set to a value corresponding to the temperature detected by the temperature detecting means. In the abnormality determination apparatus of the construction machine of any one of Claims 1-3,
An abnormality determination device for a construction machine, further comprising storage means for storing information corresponding to the abnormal operation when the abnormality determination means determines that the engine operation is abnormal. In the abnormality determination apparatus of the construction machine of any one of Claims 1-4,
An abnormality determination device for a construction machine, further comprising a transmission unit that transmits information corresponding to the abnormal operation to the base station when the abnormality determination unit determines that the engine operation is abnormal.

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