JP2003254137A - Engine control device for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably control engine speed during recovery when noise is generated on a signal in a signal line connecting a vehicle body controller and an engine controller or the line breaks in an electronic control type engine control device. <P>SOLUTION: Connection between an EC dial 4 and the vehicle body controller 5 can be switched to connection between the EC dial 4 to the engine controller 3 by switching a switch 8. When a disturbance to disable engine speed control such as noise on signal in the communication route 6 or breakage of the communication route 6 occurs to stop an engine 1, an operator switches the switch 8 to directly input command signal of the EC dial 4 to the engine controller 3. The engine controller 3 computes a target engine speed from the command signal of the EC dial and controls engine speed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in a construction machine such as a hydraulic excavator, and sends a target engine speed calculated and set by a vehicle body controller to an engine controller and controls the engine by the engine controller. Regarding

[0002]

2. Description of the Related Art A construction machine such as a hydraulic excavator is equipped with a diesel engine as a prime mover. This diesel engine (hereinafter simply referred to as an engine) has a mechanical governor system that controls fuel injection using a motor-driven mechanical governor and an electronic control system that controls fuel injection by opening and closing a valve by electronic control. ,recent years,
Electronic control methods are increasing with the diversification of control.

FIG. 12 shows a mechanical governor system, and FIGS. 13 and 14 show an electronic control system.

In FIG. 12, the mechanical governor system includes a vehicle body controller 105, and
Reference numeral 5 calculates a target engine rotation based on a voltage signal from an engine control dial (hereinafter referred to as an EC dial) 104. Further, the vehicle body controller 105 is an engine control motor (hereinafter referred to as an EC motor) 1
By rotating 03 and operating the governor 102, the engine speed is controlled to reach the target engine speed.

In FIG. 13, in the electronic control system, the engine controller 20 is provided separately from the vehicle body controller 205.
Equipped with 3. The vehicle body controller 205 is equipped with an automatic engine control system such as auto idle control and mode switching control, and calculates a target engine speed based on a voltage signal from an engine control dial (hereinafter referred to as an EC dial) 104, and controls them. When the system is operating, priority is given to the instruction of the EC dial 104, and the target rotational speed is set by the control system. The vehicle body controller 205 computes the target rotational speed calculated and set in this way and outputs a corresponding voltage (for example, idle rotational speed =
1V ~ maximum rotation speed = 4V), and convert it to harness 2
It is sent to the engine controller 203 via 06. The engine controller 203 controls the fuel adjustment device 202 on the basis of the voltage signal input from the vehicle body controller 205, and controls the engine speed so that the target engine speed is reached.

FIG. 14 shows the harness 2 shown in FIG.
While a voltage signal corresponding to the target engine speed is sent to the engine controller 203 via 06, a signal line connecting the vehicle body controller 305 and the engine controller 303 is used as a communication path 306, and serial communication or CA communication is performed.
A target engine speed signal is transmitted from the vehicle body controller 305 to the engine controller 303 by N communication.

[0007]

As described above, the engine control device for the construction machine is shifting to the electronic control system because it is easy to cope with the diversification of control. However, in the electronic control method, if the signal of the harness 206 or the communication path 306 is noisy, or if it is disconnected, it becomes impossible to control the engine speed, which affects the operation of the vehicle body, or the engine stops and moves by itself. There is a problem that you can not do.

For example, in the electronic control system shown in FIG.
When the vehicle body controller 205 is sending a target engine speed of 1 V, which is a voltage of an idle speed, to the engine controller 203, if a large voltage (a kind of noise) is input from the outside due to deterioration of the covering of the harness 206 or the like. , The engine blows up or follows the fluctuation of the voltage from the outside, the engine speed sharply rises and falls,
It affects the body operation. Further, if the harness 206 is broken during work on the road, the engine 101 stops and it becomes impossible to move by itself.

In the electronic control system shown in FIG. 14 as well, if noise is added to the signal on the communication path 306 or the communication path 306 is broken, the same problem occurs.

An object of the present invention is to provide an engine control device of electronic control type with noise on the signal of a signal line connecting the vehicle body controller and the engine controller,
It is an object of the present invention to provide an engine control device for a construction machine, which can realize stable engine speed control until it is restored even if it is broken.

[0011]

(1) In order to achieve the above first object, the present invention provides an engine rotation instruction device,
A vehicle body controller that calculates a target engine speed based on an instruction from the engine rotation instruction device, an engine controller that calculates a fuel injection command based on the target engine speed from the vehicle body controller, and an engine rotation based on the fuel injection command. An engine control device for a construction machine, comprising: a fuel adjustment device for controlling the number of fuel cells; and a signal line for sending a target engine rotation speed calculated by the vehicle body controller from the vehicle body controller to the engine controller. Abnormality detecting means for detecting an abnormality in the target engine speed sent to the engine controller, means for generating a target engine speed for emergency, and the abnormality detecting means for detecting an abnormality in the target engine speed. Target engine from body controller Switching the emissions rotational speed to the target engine speed for the emergency, this is intended to comprise a selection means for outputting a target engine speed for calculating the fuel injection command.

As described above, the abnormality detecting means, the means for generating the target engine speed for emergency, and the selecting means are provided.
When an abnormality in the target engine speed is detected, the target engine speed from the vehicle body controller is switched to the emergency target engine speed, and by outputting this as the target engine speed, noise is added to the signal on the signal line. When the signal line is broken, it becomes possible to control the engine speed by the target engine speed for emergency.
Until the engine is restored, stable engine speed control can be realized with the target engine speed for emergency use. As a result, it is possible to avoid the adverse effect on the vehicle body operation caused by the sudden increase or decrease of the engine speed and to perform the work safely, and it is possible to prevent the vehicle from being stuck on the road even if the wire is disconnected during the work on the road.

(2) In the above item (1), preferably,
The operating means further comprises a manual operating means and an operation detecting means for detecting whether or not the manual operating means is operated, and the selecting means is for emergency use when the operation of the manual operating means is detected by the operation detecting means. The target engine speed shall be maintained.

As a result, even if the abnormal state occurs discontinuously, for example, the signal line is repeatedly disconnected and short-circuited (normal state), or noise is repeated or not, the manual operation means is once operated. After that, the selecting means always holds the emergency target engine speed, so that even in that case, stable engine speed control can be realized until the engine is restored.

(3) Further, in the above (1), preferably, the means for generating the target engine speed for emergency use directly inputs an instruction from the engine speed instruction device and responds to the instruction. It is a means for calculating a target engine speed to obtain the emergency target engine speed.

As a result, the target engine speed corresponding to the instruction of the engine speed instruction device can be given as the target engine speed for emergency, and therefore the engine speed can be controlled by the engine speed instruction device until the engine is restored. Can be controlled.

(4) Further, in the above (1), preferably, a connection switching means is further provided for switching the connection between the engine rotation instruction device and the vehicle body controller to the connection between the engine rotation instruction device and the engine controller.
The means for generating the target engine rotation speed for emergency use is configured to switch the connection between the engine rotation instruction device and the vehicle body controller to the connection between the engine rotation instruction device and the engine controller, and It is a means for directly inputting an instruction and calculating a target engine speed according to the instruction to obtain the target engine speed for emergency.

As a result, after switching the connection between the engine rotation instruction device and the vehicle body controller to the connection between the engine rotation instruction device and the engine controller, the above (3) is performed.
As described above, since the target engine speed corresponding to the instruction of the engine speed instruction device is given as the target engine speed for emergency, the engine speed instruction device controls the engine speed until the engine is restored. be able to.

(5) Further, in the above item (1), preferably, a connection switching means for switching the connection between the engine rotation instruction device and the vehicle body controller to the connection between the engine rotation instruction device and the engine controller is further provided,
The means for generating the target engine rotation speed for emergency use is configured to switch the connection between the engine rotation instruction device and the vehicle body controller to the connection between the engine rotation instruction device and the engine controller, and It is a means for directly inputting an instruction, calculating a target engine speed in accordance with the instruction, and setting it as the emergency target engine speed, wherein the selecting means includes first means for setting a minimum engine speed, and Second means for switching the target engine speed from the vehicle body controller to the minimum engine speed when the abnormality detecting means detects an abnormality in the target engine speed; the emergency target engine speed and the minimum engine speed; Third means for selecting the larger one of the rotation speeds.

When an abnormality is detected in this way, the lowest engine speed is first set as the target engine speed for emergency, so that the abnormal situation can be quickly avoided. Further, after switching the connection between the engine rotation instruction device and the vehicle body controller to the connection between the engine rotation instruction device and the engine controller, the engine rotation speed is set as the target engine rotation speed for emergency as described in (3) above. Since the target engine speed according to the instruction of the instruction device is given, the engine speed can be controlled by the engine speed instruction device until the engine is restored.

(6) In above (5), preferably,
The connection switching means further comprises connection switching detection means for detecting that the connection between the engine rotation instruction device and the vehicle body controller has been switched to the connection between the engine rotation instruction device and the engine controller. The means holds the minimum engine speed when the connection switching detecting means detects the connection switching.

As a result, similarly to the above (2), the signal line repeats disconnection and short circuit (normal state),
Even if the abnormal condition occurs discontinuously, such as when the signal is noisy or does not repeat, once the connection is switched between the engine rotation indicator and the engine controller, the selection means is always for emergency use. Since the target engine speed is maintained, even in that case, stable engine speed control can be realized until the engine is restored.

(7) Further, in the above (1), preferably, a signal line for connecting the engine rotation instruction device to both the vehicle body controller and the engine controller is further provided, and the target engine speed for emergency is set. The means for generating is a means for directly inputting an instruction from the engine speed instruction device through the signal line, calculating a target engine speed according to the instruction, and setting the target engine speed for emergency.

As soon as an abnormality is detected, the target engine speed corresponding to the instruction from the engine speed instruction device is given as the emergency target engine speed.
The engine speed can be quickly controlled by the engine speed instruction device.

(8) In the above item (7), preferably,
The operating means further comprises a manual operating means and an operation detecting means for detecting whether or not the manual operating means is operated, and the selecting means is for emergency use when the operation of the manual operating means is detected by the operation detecting means. The target engine speed shall be maintained.

As a result, as described in (2) above, the signal line is repeatedly disconnected and short-circuited (normal state), and the signal is repeatedly subjected to noise or not, and the abnormal state is discontinuous. Even if it occurs, since the selecting means always holds the target engine speed for emergency after operating the manual operating means once, even in that case, it is necessary to realize stable engine speed control until it is restored. You can

(9) Further, in the above (7), preferably, the wireless communication means further comprises wireless communication detection means for detecting the presence or absence of communication from the wireless communication means, and the selection means includes the wireless communication means. When the communication detecting means detects communication from the wireless communication means, the emergency target engine speed is held.

As a result, similarly to the above (2), the signal line repeats disconnection and short circuit (normal state),
Even if the abnormal condition occurs discontinuously, such as repeating noise on the signal or not, the selecting device always sets the target engine speed for emergency after communicating from the wireless communication device. Since it is held, even in that case, stable engine speed control can be realized until the engine is restored.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

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

In FIG. 1, reference numeral 1 denotes an engine mounted on a construction machine, for example, a hydraulic excavator which is a typical example of the construction machine. The engine 1 drives a hydraulic pump (not shown), and the pressure discharged from the hydraulic pump. Various actuators such as boom cylinders and arm cylinders are driven by oil to perform various operations such as excavation work and traveling work.

The engine 1 is, for example, a diesel engine, and is equipped with an electronically controlled fuel adjusting device 2. The fuel adjustment device 2 is controlled by a fuel injection command from the engine controller 3, and controls the engine speed.

An engine control dial (hereinafter appropriately referred to as an EC dial) 4 is provided as a rotation instruction device of the engine 1, and an instruction signal (voltage) of the EC dial 4 is sent to the vehicle body controller 5.

The vehicle body controller 5 calculates the target engine speed from the instruction signal (voltage) of the EC dial 4.
Further, the vehicle body controller 5 is equipped with an automatic engine control system such as automatic idle control and mode switching control. When these control systems are operating, the target engine speed by the instruction signal (voltage) of the EC dial 4 is set. To output the target speed set by the control system. The vehicle body controller 5 sends the calculated and set target rotational speed to the engine controller 3 via a communication path (signal line) 6 by serial communication or CAN communication.

The engine controller 3 calculates a fuel injection command based on the target engine speed received from the vehicle body controller 5, controls the fuel adjusting device 2 by this fuel injection command, and sets the engine speed to the target engine speed. To control.

The EC dial 4 and the vehicle body controller 5 are connected via a harness 7a, a connection changeover switch 8 and a harness 7b. The EC dial 4 can be directly connected to the engine controller 3 via the harness 7a, the switch 8 and the harness 7c by switching the switch 8. That is, by switching the switch 8, the connection between the EC dial 4 and the vehicle body controller 5 can be switched to the connection between the EC dial 4 and the engine controller 3. The switch 8 is, for example, a toggle switch that switches the tilt of the operation pin between two positions.

When a noise occurs on the communication path 6 or the communication path 6 is broken, the engine 1 is stopped, or a failure occurs such that the engine speed cannot be controlled, the operator switches the switch 8 to switch the EC dial 4 from the EC dial 4. Is input directly to the engine controller 3. The engine controller 3 calculates the target engine speed from the instruction signal of the EC dial 4, and controls the engine speed by using this as the target engine speed for emergency.

FIG. 2 is a functional block diagram showing a control function when the engine controller 3 fails.

In FIG. 2, the engine controller 3
Has a minimum rotation speed setting unit 11, an abnormality detection unit 12, a switching unit 13, a target engine speed calculation unit 14, and a maximum value selection unit 15.

The minimum speed setting unit 11 sets the minimum engine speed of the engine 1, for example, the idle speed.

The abnormality detection unit 12 detects an abnormality in the target engine speed (communication data) sent from the vehicle body controller 5 to the engine controller 3 via the communication path 6.

As a concrete method of detecting an abnormality in the abnormality detecting section 12, a communication data abnormality caused by noise on a signal on the communication path 6 is detected by a known parity check,
Detected by checksum, CRC, etc. Also, the disconnection or short circuit of the communication path 6 is checked depending on whether the normal communication data has arrived for a certain period of time, and if the normal communication data has not arrived for a certain period of time, it is judged to be the disconnection or the short circuit. Further, as communication data abnormality, the target rotation speed sent from the communication path 6 is within the normal target rotation speed range (for example, 8
It is checked whether it is in the range of 0 to 2200 rpm), and if the target rotation speed sent from the communication path 6 is not within the normal target rotation speed range, it is determined that the combination of the vehicle body controller and the engine controller is wrong. to decide.

The switching unit 13 is a switch for selecting one of the target engine speed sent from the vehicle body controller 5 and the minimum engine speed set by the minimum speed setting unit 11, and the abnormality detection unit 12 communicates with the switch. When no abnormality is detected in the data, the target engine speed received through communication is selected, and when the abnormality is detected, the engine speed is switched to the minimum engine speed.

The target engine speed calculator 14 sends an instruction signal (voltage) to the EC dial 4 sent from the harness 7c.
Is input, and the target engine speed (target engine speed for emergency) is calculated from the voltage.

The maximum value selection unit 15 selects the larger one of the engine speed selected by the switching unit 13 and the target engine speed calculated by the calculation unit 14 as the target engine speed for control.

In the above, when the abnormality detecting section (abnormality detecting means) 12 detects an abnormality in the target engine rotational speed, the minimum engine speed setting section 11, the switching section 13, and the maximum value selecting section 15 are operated by the vehicle body controller 3. The selecting means is configured to switch the target engine speed to the emergency target engine speed and output this as the target engine speed for calculating the fuel injection command.

In the engine controller 3 configured as described above, when there is no abnormality in the target engine speed data (communication data) sent through the communication path 6, the switching unit 13 sets the target engine speed received by communication. select. At this time, since the switch 8 shown in FIG. 1 is at the position shown, the voltage sent from the EC dial input harness 7c is 0, and the target engine speed calculator 14 calculates the minimum engine speed. Therefore, the maximum value selection unit 1
In 5, the target engine speed from the switching unit 13 is selected and used as the control target speed. Therefore, the engine speed is controlled to be the target engine speed sent from the vehicle body controller 5.

When the abnormality of the target engine speed data sent via the communication path 6 is detected by the abnormality detecting section 12,
The switching unit 13 selects the lowest engine speed. Therefore, the maximum value selection unit 15 selects the minimum engine rotation speed or the minimum engine rotation speed calculated by the target engine rotation speed calculation unit 14 as the emergency target engine rotation speed, and uses it as the control target. The number of rotations. For this reason,
The rotation speed of the engine 1 drops to the minimum rotation speed.

On the other hand, the operator perceives an abnormality in the communication data on the communication path 6 due to a decrease in the engine speed, and switches the switch 8 shown in FIG. 1 from the position shown in the drawing.
The EC dial 4 and the engine controller 3 are directly connected. As a result, the target engine speed calculation unit 14 outputs E
The instruction signal (voltage) from the C dial 4 is directly input,
The calculation unit 14 calculates the target engine speed according to the voltage and outputs it to the maximum value selection unit 15. For this reason,
The maximum value selection unit 15 selects the target engine speed from the target engine speed calculation unit 14 as the emergency target engine speed, and sets it as the control target speed.
As a result, even if noise is added to the signal on the communication path 6 or the signal is broken, stable engine speed control can be realized until the signal is restored.

As described above, according to the present embodiment, there is a problem that the signal of the communication path 6 is noisy or the communication path 6 is broken, the engine 1 is stopped, and the engine speed cannot be controlled. Even if it occurs, stable engine speed control can be realized by the target engine speed calculated by the target engine speed calculator 14 (target engine speed for emergency) until the engine is restored. As a result, it is possible to avoid adverse effects on the vehicle body operation of the hydraulic excavator due to a sudden increase or decrease in the engine speed, and to perform work safely, and also to prevent the vehicle from getting stuck on the road even if it is disconnected during work on the road. it can.

When an abnormality is detected, first, the lowest engine speed is set as the target engine speed for emergency, so that the abnormal situation can be avoided quickly.

Further, after the EC dial 4 and the engine controller 3 are directly connected, the target engine speed corresponding to the instruction signal from the EC dial 4 is calculated as the target engine speed for emergency use, so that the engine is restored. Until then, the engine speed can be controlled by the EC dial 4.

A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a functional block diagram showing the control function of the engine controller when a failure occurs in the present embodiment. In the figure, the same parts as those shown in FIG. 2 are designated by the same reference numerals.

In FIG. 3, the engine controller 3
Has a function of the connection switching detection unit 16 in addition to the functions of the minimum rotation speed setting unit 11, the abnormality detection unit 12, the switching unit 13A, the target engine speed calculation unit 14, and the maximum value selection unit 15.

The connection switching detector 16 detects whether or not the connection between the EC dial 4 and the vehicle body controller 5 is switched to the connection between the EC dial 4 and the engine controller 3 by switching the switch 8. An operation detecting means for detecting whether or not the connection changeover switch 8 as the operating means is operated is configured. Further, the connection switching detector 16 monitors the input from the harness 7c (see FIG. 1), and when the instruction signal (voltage) of the EC dial 4 is input from the harness 7c, the EC dial 4 and the engine controller 3 are connected. Judge that the connection has been switched.

When no abnormality is detected in the communication data or the target engine rotation speed by the abnormality detection unit 12, the switching unit 13A selects the target engine rotation speed received by communication via the communication path 6, and the abnormality is detected. Then, when the connection switching detection unit 16 detects that the connection between the EC dial 4 and the engine controller 3 is switched to the lowest engine speed, the lowest engine speed is detected regardless of the determination result of the abnormality detection unit 12. Hold the state switched to the rotation speed.

When an abnormality occurs in the communication data of the communication path 6, for example, disconnection and short circuit (normal state) are repeated due to irregular contact of the disconnected portion of the communication path 6, or noise is added to the signal. Do not ride or repeat,
The abnormal state may occur discontinuously. In such a case, if the switching unit 13A switches only based on the determination result of the abnormality detection unit 12, the minimum engine speed of the minimum speed setting unit 11 and the target engine speed received from the communication path 6 are alternately selected, Stable engine speed control becomes impossible.

According to the present embodiment, when the operator switches the switch 8 to switch the connection between the EC dial 4 and the engine controller 3 after the abnormality detection unit 12 detects an abnormality in the communication data, the fact that Detected by the connection switching detection unit 16, the switching unit 13A holds the minimum engine speed. For this reason, after the switch 8 is once switched, the switching unit 13A always holds the minimum engine speed even if an abnormal state of communication data occurs discontinuously. Since the target engine speed calculated by the calculator 14 is selected as the target engine speed for control and the target engine speed for control is selected, stable engine speed control can be realized even in that case.

A third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a diagram showing the overall configuration of the engine control device according to the present embodiment. In the figure, the same parts as those shown in FIG. 1 are designated by the same reference numerals.

In FIG. 4, the harnesses 7a and 7b are provided with terminals 18a and 18b of the connection switching connector 18, and the EC dial 4 and the vehicle body controller 5 are connected via the harness 7a, the connection switching connector 18 and the harness 7b. Has been done. In addition, the harness 7c also has a switching connector 1
8 terminals 18c are provided, and the EC dial 4 connects the terminals of the connector 18 from the terminals 18a and 18b to the terminal 1
By switching to 8a and 18c, it is possible to directly connect to the engine controller 3 via the harness 7a, the connector 18, and the harness 7c.

As described above, also in this embodiment, the EC dial 4 and the vehicle body controller 5 are connected by using the connector 18.
Connection with EC dial 4 and engine controller 3
You can switch to the connection with.

Therefore, according to this embodiment, the same effect as that of the first embodiment can be obtained.

A fourth embodiment of the present invention is shown in FIGS.
Will be described. FIG. 5 is a diagram showing an overall configuration of an engine control device according to the present embodiment, and FIG. 6 is a functional block diagram showing a control function when a failure occurs in the engine controller according to the present embodiment. Each,
The same parts as those shown in FIGS. 1 and 2 are designated by the same reference numerals.

In FIG. 5, the EC dial 4 and the vehicle body controller 5 are connected via a harness 21. Further, the engine speed fixed switch 22 is connected to the engine controller 3A via the input line 23, and when the engine speed fixed switch 22 is turned on (closed), the input line 22 is opened.
Is connected to the ground wire 24 to be in a grounded state (short circuit).

In FIG. 6, the engine controller 3A
Is the constant target engine speed setting unit 25, the abnormality detection unit 1
2. It has the functions of the switch operation detection unit 26 and the switching unit 13A.

The constant target engine speed setting unit 25 sets a constant target speed of the engine 1 as the emergency target engine speed.

The switch operation detecting section 26 detects the operation status of the engine speed fixed switch 22.
The ground state of the input line 22 is monitored, and when the input line 22 becomes the ground state, it is determined that the engine speed fixed switch 22 is turned on.

When no abnormality is detected in the target engine rotation speed data (communication data) by the abnormality detection unit 12, the switching unit 13A selects the target engine rotation speed received by communication via the communication path 6 to detect the abnormality. When it is detected, the engine speed is switched to a constant target engine speed, and when the switch operation detecting unit 26 detects that the engine speed fixing switch 22 is turned on, the engine speed is fixed regardless of the determination result by the abnormality detecting unit 12. The state of switching to the target engine speed is maintained.

In the present embodiment configured as described above, when an abnormality is detected in the target engine speed data (communication data) sent through the communication path 6, the switching unit 13A causes the target engine speed to be constant. Select the number (target engine speed for emergency) and use it as the target speed for control. For this reason, noise is added to the signal of the communication path 6,
Even if the wire breaks, stable engine speed control can be realized until the line is restored.

Further, at this time, when the operator turns on the engine speed fixing switch 22, this is detected by the switch operation detecting unit 26, and the switching unit 13A holds a constant target engine speed. Therefore, after the switch 22 is turned on once, the switching unit 13A always maintains a constant target engine speed even if an abnormal state of communication data occurs discontinuously. Therefore, even in that case, stable engine speed control can be realized.

Therefore, according to the present embodiment, the first
Also, the same effect as that of the second embodiment can be obtained.

Further, in the present embodiment, when an abnormality is detected, the target engine speed corresponding to the instruction signal from the EC dial 4 is immediately given as the emergency target engine speed, so that the EC dial 4 can be quickly operated. The engine speed can be controlled by.

FIG. 7 and FIG. 8 show a fifth embodiment of the present invention.
Will be described. FIG. 7 is a diagram showing an overall configuration of an engine control device according to the present embodiment, and FIG. 8 is a functional block diagram showing a control function when a failure occurs in the engine controller according to the present embodiment. Each,
The same parts as those shown in FIGS. 1 and 2 are designated by the same reference numerals.

In FIG. 7, the EC dial 4 and the vehicle body controller 5 are connected via a harness 21.
In addition, the engine controller 3B includes the harnesses 21 and 31.
It is directly connected to the EC dial 4 via.

In FIG. 8, the engine controller 3B
Has respective functions of the abnormality detection unit 12, the switching unit 13, and the target engine speed calculation unit 14.

The target engine speed calculator 14 inputs the instruction signal (voltage) of the EC dial 4 sent from the harnesses 21 and 22, and calculates the target engine speed (target engine speed for emergency) from the voltage. To do.

The switching unit 13 is a switch for selecting one of the target engine speed received by communication via the communication path 6 and the target engine speed calculated by the target engine speed calculation unit 14, and the abnormality detection unit 12 When no abnormality is detected in the communication data or the target engine speed in step S1, the target engine speed received by the communication is selected, and when the abnormality is detected, the target engine speed calculated by the target engine speed calculator 14 is switched to. .

In the present embodiment configured as described above, when an abnormality is detected in the target engine speed data (communication data) sent through the communication path 6, the switching unit 13 calculates the target engine speed. The target engine speed calculated by the unit 14 (target engine speed for emergency) is selected and used as the target speed for control. Therefore, even if noise is added to the signal on the communication path 6 or the communication path 6 is broken, stable engine speed control can be realized until the signal is restored.

Therefore, according to the present embodiment, the first
The same effect as that of the embodiment can be obtained.

FIG. 7 and FIG. 9 show the sixth embodiment of the present invention.
Will be described. The overall configuration of the device according to this embodiment is the same as that of the fifth embodiment shown in FIG.
FIG. 9 is a functional block diagram showing the control function of the engine controller according to the present embodiment when a failure occurs. In the figure, the same parts as those shown in FIGS. 2 and 8 are designated by the same reference numerals. ing.

In FIG. 9, the engine controller 3B
(See FIG. 7) is the abnormality detection unit 12, the switching unit 13A,
In addition to the functions of the target engine speed calculation unit 14, the handy terminal setting ON / OFF unit 32 is provided.

Handy terminal setting ON / OFF section 3
2 monitors the signal from the external handy terminal,
When the handy terminal is operated, the handy terminal is set to ON.

When no abnormality is detected in the communication data by the abnormality detecting unit 12, the switching unit 13A selects the target engine rotation speed received by the communication, and when the abnormality is detected, the target engine rotation speed calculated by the calculating unit 14 is selected. When the handy terminal ON is set in the handy terminal setting ON / OFF section 32 while switching to the number, the abnormality detection section 1
The state in which the target engine speed calculated by the calculation unit 14 is switched is maintained regardless of the determination result in 2.

According to the present embodiment, when the operator operates the handy terminal after the abnormality detection section 12 detects an abnormality in the target engine speed data (communication data), the handy terminal setting ON / OFF section 32 is operated. The handy terminal is set to ON, and the switching unit 13A holds the target engine speed calculated by the calculation unit 14.
For this reason, after operating the handy terminal once, even if an abnormal state of communication data occurs discontinuously, the switching unit 13A always holds the target engine speed calculated by the calculation unit 14 and controls it. Since the target engine speed is set to, the stable engine speed control can be realized even in that case.

The seventh embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a diagram showing the overall configuration of the engine control device according to the present embodiment.
Is a functional block diagram showing a control function when a failure occurs in the engine controller in the present embodiment,
The same parts as those shown in FIGS. 1, 5 and 7, FIG. 2, FIG. 6 and FIG. 8 are designated by the same reference numerals.

In FIG. 10, the EC dial 4 and the vehicle body controller 5 are connected via a harness 21, and the engine controller 3C is connected via a harness 21 and 31 to an E switch.
It is directly connected to the C dial 4. Further, the engine speed fixed switch 22 is connected to the engine controller 3C via the input line 23, and when the engine speed fixed switch 22 is turned on (closed), the input line 22 is connected to the ground line 24 to be grounded (short). And

In FIG. 11, the engine controller 3
C has the function of the switch operation detection unit 26 in addition to the functions of the abnormality detection unit 12, the switching unit 13A, and the target engine speed calculation unit 14.

As described above, the switch operation detection unit 26 detects the operation status of the engine speed fixed switch 22, monitors the ground state of the input line 22, and when the input line 22 is in the ground state, the engine rotation speed is changed. Number fixed switch 2
It is determined that 2 is turned on.

When no abnormality is detected in the target engine rotation speed data (communication data) by the abnormality detection unit 12, the switching unit 13A selects the target engine rotation speed received by communication via the communication path 6, and detects the abnormality. When detected, computing unit 1
When the switch operation detecting unit 26 detects that the engine speed fixing switch 22 is turned on while switching to the target engine speed (target engine speed for emergency) calculated in step 4, The state of switching to the target engine speed calculated by the calculation unit 14 is held regardless of the determination result.

In the present embodiment configured as described above, when an abnormality is detected in the target engine speed data (communication data) sent through the communication path 6, the switching unit 13A calculates the target engine speed. The target engine speed calculated by the unit 14 (target engine speed for emergency) is selected and used as the target speed for control. Therefore, even if noise is added to the signal of the communication path 6 or the communication path 6 is broken or short-circuited, stable engine speed control can be realized until the signal is restored.

At this time, when the operator turns on the engine speed fixing switch 22, this is detected by the switch operation detecting unit 26, and the switching unit 13A calculates the target engine speed calculated by the calculating unit 14 (for emergency use). The target engine speed) is maintained. Therefore, once switch 2
After turning on 2, even if an abnormal state of communication data occurs discontinuously, the switching unit 13A always holds the target engine rotation speed calculated by the calculation unit 14, and uses it as the target engine rotation speed for control. Therefore, even in that case, stable engine speed control can be realized.

Therefore, according to the present embodiment, the first
Also, the same effect as that of the second embodiment can be obtained.

Further, in this embodiment, when an abnormality is detected, the target engine speed corresponding to the instruction signal from the EC dial 4 is immediately given as the emergency target engine speed, so that the EC dial 4 can be quickly operated. The engine speed can be controlled by.

In the above embodiment, the signal line connecting the vehicle body controller 5 and the engine controllers 3 to 3C is used as the communication path 6, and the target vehicle engine speed calculated by the vehicle body controller 5 from the vehicle body controller 5 to the engine controller 3 is calculated. Although the number is sent by serial communication or CAN communication, as in the conventional technique shown in FIG. 13, the signal line connecting the vehicle body controller 5 and the engine controllers 3 to 3C is the harness 206, and in the vehicle body controller 5, This is also applicable to one that converts the calculated and set target rotational speed into a corresponding voltage (for example, idle rotational speed = 1 V to maximum rotational speed = 4 V) and sends the voltage signal from the vehicle body controller 5 to the engine controller 3 to the vehicle body controller 5. The invention can be applied, and the same effect can be obtained in this case as well.

[0095]

According to the present invention, when the signal on the signal line is noisy or the signal line is broken, the engine speed control can be performed by the target engine speed for emergency use. During this period, stable engine speed control can be realized with the target engine speed for emergency use, and it is possible to work safely on the road while avoiding the adverse effects on vehicle body operation due to sudden increases and decreases in engine speed. Even if the wire is broken inside, it can be prevented from getting stuck on the road.

In addition, even if the abnormal state occurs discontinuously, such as the signal line repeatedly being disconnected and short-circuited (normal state), the signal being noisy or not, and the like, the manual operation means is once used. After the operation, the selecting means always holds the emergency target engine speed, so that even in that case, stable engine speed control can be realized until the engine is restored.

Further, since the target engine speed corresponding to the instruction of the engine speed instruction device can be given as the emergency target engine speed, until the engine is restored,
The engine speed can be controlled by the engine speed instruction device.

When an abnormality is detected, first, the minimum engine speed is set as the target engine speed for emergency, so that the abnormal situation can be quickly avoided.

Further, as soon as an abnormality is detected, the target engine speed corresponding to the instruction from the engine speed instruction device is given as the emergency target engine speed, so that the engine speed instruction device can quickly determine the engine speed. Can be controlled.

[Brief description of drawings]

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

FIG. 2 is a functional block diagram showing a control function when an engine controller fails.

FIG. 3 is a functional block diagram showing a control function when a failure occurs in the engine controller according to the second embodiment of the present invention.

FIG. 4 is a diagram showing an overall configuration of an engine control device for a construction machine according to a third embodiment of the present invention.

FIG. 5 is a diagram showing an overall configuration of an engine control device for a construction machine according to a fourth embodiment of the present invention.

FIG. 6 is a functional block diagram showing a control function when an engine controller fails.

FIG. 7 is a diagram showing an overall configuration of an engine control device for a construction machine according to a fifth embodiment of the present invention.

FIG. 8 is a functional block diagram showing a control function when an engine controller fails.

FIG. 9 is a functional block diagram showing a control function when a failure occurs in the engine controller according to the sixth embodiment of the present invention.

FIG. 10 is a diagram showing an overall configuration of an engine control device for a construction machine according to a seventh embodiment of the present invention.

FIG. 11 is a functional block diagram showing a control function when an engine controller fails.

FIG. 12 is a diagram showing an engine control device for a conventional mechanical governor type construction machine.

FIG. 13 is a diagram showing a conventional engine control device for an electronically controlled construction machine.

FIG. 14 is a diagram showing another conventional engine control device for an electronically controlled construction machine.

[Explanation of symbols]

1 engine 2 Fuel adjustment device 3,3A, 3B, 3C Engine controller 4 Engine control dial (EC dial) 5 Body controller 6 communication path (signal line) 7a, 7b, 7c harness 8 Connection selector switch 11 Minimum speed setting section 12 Abnormality detector 13, 13A switching unit 14 Target engine speed calculator 15 Maximum value selection section 16 Connection switching detector 18 Connection switching connector 21 harness 22 Engine speed fixed switch 23 input line 24 Ground wire 25 Constant target engine speed setting unit 26 Switch operation detector 31 harness 32 Handy terminal setting ON / OFF section

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 29/02 F02D 29/02 H K 41/14 330 41/14 330D F02M 51/00 F02M 51/00 A (72) Inventor Kazunori Nakamura 650 Kazutachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd., Tsuchiura Plant (72) Inventor Yasushi Arai 650, Jincho-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. F-term, Tsuchiura Plant (Reference) 2D015 CA01 3G066 AA07 AA15 AB02 BA33 CE29 CE30 DA01 DB11 DB15 DC09 3G093 AA10 AB01 BA06 BA10 CA12 CB14 DA01 EA03 EC01 FA07 FB05 3G301 HA02 HA28 JB03 JB07 KA23 LB13 MA11 NE16 NE25 PE01A

Claims (9)

[Claims] 1. An engine rotation instruction device, a vehicle body controller that calculates a target engine speed based on an instruction from the engine rotation instruction device, and an engine that calculates a fuel injection command based on the target engine speed from the vehicle body controller. An engine control device for a construction machine including a controller, a fuel adjustment device that controls an engine speed based on the fuel injection command, and a signal line that sends the target engine speed calculated from the vehicle body controller to the engine controller by the vehicle body controller. An abnormality detecting means for detecting an abnormality in the target engine speed sent from the vehicle body controller to the engine controller through the signal line, a means for generating a target engine speed for emergency, and the target for the abnormality detecting means. Abnormal engine speed is detected And a selecting means for switching the target engine speed from the vehicle body controller to the emergency target engine speed and outputting this as the target engine speed for calculating the fuel injection command. Engine control device for construction machinery. 2. The engine control device for a construction machine according to claim 1, further comprising a manual operation means, and an operation detection means for detecting whether or not the manual operation means is operated, wherein the selection means includes the operation. An engine control device for a construction machine, characterized in that when the operation of the manual operation means is detected by the detection means, the target engine speed for emergency is held. 3. The engine control device for a construction machine according to claim 1, wherein the means for generating the target engine speed for emergency use directly inputs an instruction from the engine speed instruction device and responds to the instruction. An engine control device for a construction machine, which is a means for calculating a target engine speed of the vehicle and setting the target engine speed as the emergency target engine speed. 4. The engine control device for a construction machine according to claim 1, further comprising connection switching means for switching a connection between the engine rotation instruction device and the vehicle body controller to a connection between the engine rotation instruction device and the engine controller. The means for generating the target engine speed for emergency use is configured such that the connection between the engine rotation instruction device and the vehicle body controller is switched to the connection between the engine rotation instruction device and the engine controller. The engine control device for a construction machine, which is a means for directly inputting the instruction of, and calculating a target engine speed according to the instruction and setting the target engine speed as the emergency target engine speed. 5. The engine control device for a construction machine according to claim 1, further comprising connection switching means for switching a connection between the engine rotation instruction device and the vehicle body controller to a connection between the engine rotation instruction device and the engine controller. The means for generating the target engine speed for emergency use is configured such that the connection between the engine rotation instruction device and the vehicle body controller is switched to the connection between the engine rotation instruction device and the engine controller. Is a means for directly inputting the instruction, calculating the target engine speed according to the instruction, and setting the target engine speed for the emergency, wherein the selecting means includes first means for setting the minimum engine speed, When the abnormality detecting means detects an abnormality in the target engine speed, Second switching of the target engine speed to the minimum engine speed
An engine control device for a construction machine, comprising: means, and third means for selecting a larger one of the emergency target engine speed and the minimum engine speed. 6. The engine control device for a construction machine according to claim 5, wherein the connection switching means switches the connection between the engine rotation instruction device and the vehicle body controller to the connection between the engine rotation instruction device and the engine controller. A construction machine characterized by further comprising connection switching detection means for detecting that the second engine of the selection means holds the minimum engine speed when connection switching is detected by the connection switching detection means. Engine controller. 7. The engine control device for a construction machine according to claim 1, further comprising a signal line connecting the engine rotation instruction device to both the vehicle body controller and the engine controller, the target engine speed for emergency use. Means for directly generating an instruction from the engine speed instruction device through the signal line, calculating a target engine speed according to the instruction, and setting the target engine speed for emergency. An engine control device for construction machinery. 8. The engine control device for a construction machine according to claim 7, further comprising a manual operation means, and an operation detection means for detecting whether or not the manual operation means is operated, wherein the selection means includes the operation. An engine control device for a construction machine, characterized in that when the operation of the manual operation means is detected by the detection means, the target engine speed for emergency is held. 9. The engine control device for a construction machine according to claim 7, further comprising wireless communication means and wireless communication detection means for detecting the presence or absence of communication from the wireless communication means, wherein the selection means is the An engine control device for a construction machine, which holds the target engine speed for emergency when the communication from the wireless communication means is detected by the wireless communication detection means.