JP2617365B2 - Engine control device for construction machinery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine control device for a construction machine, and more particularly to an improvement for preventing an error between an engine rotation command value and an actual engine speed.

[Conventional technology]

In general, in construction machines such as power shovels and bulldozers, a diesel engine is provided with an all-speed governor, and the governor controls the output torque of the engine as shown by a solid line in FIG. In this engine output characteristic, the regulation line 1 is determined in accordance with the engine speed command value input to the governor.

A variable displacement hydraulic pump is connected to the output shaft of the engine, and the hydraulic pump is driven by the engine. Then, the hydraulic oil from the hydraulic pump is supplied to hydraulic actuators for driving the working machine and traveling of the construction machine via the operation valve, and drives these hydraulic actuators.

In this variable displacement type hydraulic pump, pump absorption torque control as shown by a dashed line in FIG. 7 is performed. Tilt angle control of a swash plate is performed to obtain the absorption torque shown by a dashed line in FIG. At point M1, the pump absorption torque matches the engine torque. In this pump absorption torque control, the tilt angle of the swash plate is controlled so that the product of the discharge pressure of the pump and the discharge flow rate of the pump, that is, the pump absorption horsepower becomes constant. May be adopted.

[Problems to be solved by the invention]

By the way, when performing such engine control and pump control, in the conventional device, the engine rotational speed is reduced due to the manufacturing variation and aging deterioration of the engine and governor components such as the governor throttle lever, the throttle actuator, and the link mechanism. There is a problem that an error between the command value and the actual engine speed value increases, and the driver feels strange.

In addition, when the pump absorption torque control as described above is performed, the pump absorption torque overloads the engine output due to an error between the engine speed command value and the actual engine speed value, and the engine speed decreases. Or the pump absorption torque is suppressed too low to reduce the work amount, and the pump absorption torque and the engine torque cannot be accurately matched.

The present invention has been made in view of such circumstances,
An object of the present invention is to provide a diesel engine control device for a construction machine that causes an actual engine speed to accurately follow an engine speed command value.

[Means for solving the problem]

According to the present invention, an all-speed governor having a control lever drive device that variably drives the position of the control lever so that an engine output characteristic corresponding to the input target engine speed is selected, and the fuel injection amount is increased by the all-speed governor In a diesel engine control device for a construction machine having a controlled diesel engine, a hydraulic pump driven by the output of the diesel engine, and a hydraulic actuator driven by the hydraulic pressure supplied from the hydraulic pump, the hydraulic actuators are all provided. Neutral detection means for detecting that the vehicle is in a neutral state, diesel engine speed detection means for detecting the rotation speed of the diesel engine, and when a detection signal is input from the neutral detection means,
First control means for sequentially inputting a plurality of different engine speed command values to the control lever driving device to actually drive the diesel engine and the all-speed governor in a no-load state; and in the actual driving state of the diesel engine, The detection output of the diesel engine rotation detecting means is sequentially taken in corresponding to each of the plurality of different engine rotation speed designation values, and data indicating a correspondence relationship between an engine rotation speed command value and an actual engine rotation speed is stored in a predetermined memory table. A second control means for storing, when the construction machine is operating, a real engine speed value equal to the target engine speed value is specified in the memory table, and a diesel engine corresponding to the specified real engine speed value is designated. A rotational speed command value is read from the memory table, and the read diesel engine is read. Jin rotation speed command value so as comprising a third control means for outputting to the control lever drive device as the correction target engine rotational speed.

[Action]

According to this configuration, when it is detected that all the hydraulic actuators are in the neutral state, the engine correction command value registration mode is executed. According to the engine correction command value registration mode, an engine speed command value that changes as appropriate is input to the engine and the engine is actually driven. Then, the value of the actual engine speed corresponding to the change in the engine speed command value in this engine driving state is detected,
Data indicating this correspondence is stored and registered.

During the subsequent normal operation, an actual engine speed having the same value as the desired engine speed command value to be output is extracted from the stored data, and the engine speed command corresponding to the extracted actual engine speed command is output. A value is selected from the stored data, and the selected engine speed command value is output to the engine as corrected data.

That is, according to the present invention, the engine speed command value to be output is corrected based on the data indicating the actual correspondence between the actual engine speed obtained by actually driving the engine and the engine speed command value. To do.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows an embodiment of the present invention.
Is provided with a fuel injection pump 2 and an all-speed governor 3. A control lever 4 of the governor 3 is driven by a motor 5, and a driving position of the lever 4 is detected by a sensor 6.

The throttle amount setting device 7 includes a dial 7a and a potentiometer 7b, and a set value Ns of the engine speed is input from the throttle amount setting device 7 to the controller 10.

A rotation sensor 20 is attached to the output shaft of the engine 1, and the actual rotation speed Ne of the engine 1 is
Is detected and input to the controller 10.

The variable displacement hydraulic pump 8 is driven by the engine 1 and supplies the oil in the tank 9 to the hydraulic actuator 12 via the operation valve 11. The hydraulic machine 12 drives a working machine and a traveling body of a construction machine.

In the variable displacement hydraulic pump 8, the pump absorption torque control described above is performed by controlling the tilt angle of the swash plate by a pump displacement control device 13 including various valves. The pump displacement control device 13 is controlled by the controller 10.

The operation lever 14 executes switching control and flow rate control of the operation valve 11. Neutral detector 15 for operating lever 14
The neutral detection signal NT is input to the controller 10.

In this case, the pump 8, the operating valve 11, the hydraulic actuator 12, the operating lever 14, and the like are shown as one for convenience, but a plurality of them are usually provided. Therefore, the neutral detector 15 also substantially detects that all of the operation levers are neutral. That is, the neutral detector detects that the construction machine has stopped working.

The operation panel 16 displays “heavy drilling”, “digging”, “straightening”,
A work mode selection switch for selecting a work mode such as "fine operation", a power mode selection switch for selecting the engine output and the output ratio of the hydraulic pump, an auto deceleration switch and a lever for automatically lowering the engine speed during lever neutral In addition to a soft mode switch that gradually shuts off oil flowing to the hydraulic actuator in neutral, a turning lock switch, a priority work machine selection switch, a wiper switch, a lamp switch, a buzzer switch, and the like are provided. In this case, the operation panel 16 is provided with a correction command value registration mode switch SW1 for instructing execution of an engine correction command value registration mode described later. The output of each switch on the operation panel 16 is input to the controller 10.

The controller 10 determines an engine rotation command value Nc to be input to the governor motor 5 of the engine 1 according to the ON state of each switch on the operation panel 16 and the engine rotation set value Ns input from the throttle dial 7. That is, an engine rotation command to be input to the governor motor 5 according to a work mode such as “heavy excavation”, “excavation”, “correction”, “fine operation”, or a selected power mode, and whether or not there is an auto deceleration. Various values Nm are set in advance, and the controller 10 selects the smaller one of the engine rotation command value Nm determined by the mode and the engine rotation set value Ns from the throttle dial 7, and outputs the selected signal. It is determined as an engine rotation command value Nc 'to be input to the governor motor 5 of the engine 1. As will become clear later, the engine rotation command value Nc 'is different from the engine rotation command value Nc actually output to the governor motor 5.
In order to avoid confusion, the engine rotation command value Nc 'is hereinafter referred to as a temporary engine rotation command value Nc'. More controllers
The processing of 10 is normally performed in the conventional apparatus, and the processing described below is processing added by the present invention. This processing will be described with reference to the flowcharts shown in FIGS.

That is, the controller 10 detects that the engine correction command value registration mode switch SW1 on the operation panel 16 is turned on (step 100), and detects that all the operation levers are in the neutral state by the neutral detector 15. Then, a process for creating an engine command value correction table is executed (step 12).
0).

This engine command value correction table includes an engine rotation command value Nc output to the governor motor 5 as shown in FIG.
And a correspondence relationship between the actual engine speed Ne detected by the rotation sensor 20 and the actual engine speed Ne. The specific relationship is registered as follows.

<< Method 1 >> Using the operation panel described above, the operator sequentially changes each mode (heavy excavation, excavation, straightening,
Fine operation). The controller 10 outputs the engine rotation set value corresponding to the selected mode to the cabana motor 5.
, The engine 1 is actually driven, and the actual engine speed Ne at this time is detected by the rotation sensor 230. After associating the output engine speed set value with the input actual engine speed Ne, the controller 10 stores the data in a memory in the controller 10 after appropriately applying linear interpolation or curve interpolation.

<< Method 2 >> When the operator gradually rotates the dial 7a of the throttle amount setting device 7, the continuously changing engine rotation set value Ns is input to the controller 10, and the controller 10 outputs the engine rotation set value to the governor motor 5 , The engine 1 is actually driven, and the actual engine speed Ne at this time is detected by the rotation sensor 230. Controller 10
Stores the output engine speed set value Ns and the input actual engine speed Ne in the memory in the controller 10 in association with each other.

<< Method 3 >> Steps 100 and 1 in FIG.
When the condition 10 is satisfied, as shown in FIG. 5, the engine rotation command value Nc that increases from the predetermined minimum set value Nmin to the maximum set value Nmax and then decreases from the maximum set value Nmax to the minimum set value Nmin is automatically set. A function that can output the engine 1 is added, and the engine rotation command value Nc is automatically output to the governor motor 5 to actually drive the engine 1. Then, the actual engine speed Ne at this time is detected by the rotation sensor 230.
In this case, there is often a difference in the actual engine speed value Ne between when the command value of the engine speed is increased and when it is decreased, as shown by L1 and L2 in FIG. Therefore,
The controller 10 calculates, for example, an average (line L3) of the detected values of the forward path indicated by the line L1 and the detected values of the return path indicated by the line L2, and uses the average value in the correction table. In this way, the obtained actual engine speed value Ne is stored in the memory in the controller 10 in association with the engine speed set value Ns.

The controller 10 creates and stores a correction table in the manner described above. When the controller 10 detects that the engine correction command value registration mode switch SW1 has been turned off, the controller 10 ends this registration mode (step 13).
0).

Thereafter, when the working machine or the traveling body of the construction machine is actually operated, the controller 10 executes the following correction of the engine rotation command value.

That is, as described above, the controller 10 selects the smaller one of the engine rotation command value Nm determined by the operation mode selection by the operator and the engine rotation set value Ns from the throttle dial 7, and outputs the selected signal. First, a temporary engine rotation command value Nc 'to be input to the governor motor 5 of the engine 1 is determined (step 200 in FIG. 3). Then, the controller 10 corrects the determined temporary engine rotation command value Nc 'using the registered correction table, and outputs the correction value to the governor motor 5 of the engine 1 as the engine rotation command value Nc.

That is, the controller 10 extracts the actual engine speed value Ne having the same value as the determined temporary engine speed command value Nc 'from the correction table shown in FIG. 4 (step 21).
0), an engine rotation command value Nc corresponding to the extracted actual engine rotation value Ne is read from this correction table (step 220). Then, the read engine rotation command value Nc is output to the governor motor 5 of the engine 1 (step 230). That is, an actual engine speed value Ne having the same value as the desired temporary engine speed command value Nc 'is extracted from the correction table, and the engine speed command value associated with the extracted actual engine speed value Ne is extracted.
By reading Nc from the correction table, the temporary engine rotation command value Nc 'is corrected by the read engine rotation command value Nc (the engine rotation command value from which the command value is read).
Nc), and outputs the corrected engine rotation command value Nc to the governor motor 5 of the engine 1 to accurately control the engine rotation to a desired engine rotation command value Nc '.

Because the relationship between the actual engine speed value Ne and the engine speed command value Nc registered in the correction table is obtained by actually driving the engine 1,
When the engine 1 is driven in accordance with the engine rotation command value Nc obtained by inversely converting the correction table in a sense as in the present embodiment, even if there is a variation in manufacturing of engine parts or a change over time, a command based on these is used. As a result, all errors between the value and the actual value are completely absorbed, and the desired engine rotation command value Nc 'can be reliably obtained from the engine 1. That is, the actual engine speed Ne can be completely matched with the desired engine speed command value Nc '.

In the above embodiment, when the neutral detection signal NT is input from the neutral detector 15 to the controller, the controller 10 immediately creates the correction table. However, as shown in FIG.
Starting the table creation after a predetermined set time T has elapsed from the input of the NT allows a more accurate actual engine speed Ne to be obtained. That is, even if the load is released due to the operation lever 14 becoming neutral, the engine does not always immediately enter a steady state, and it usually takes some time to reach a steady state. Therefore, in this case, the sampling of the actual engine speed Ne is performed after the set time T has elapsed from the lever neutral point. Therefore, in this case, if the operation lever 14 is displaced from the neutral position before the set time T has elapsed, the sampling of the actual engine speed Ne is not performed.

Further, in the above embodiment, the engine correction command value registration mode switch SW1 is turned on when the correction table is created.However, this mode switch SW1 is omitted, and when the operation lever 14 is in the neutral state, the correction table is always turned on. A registration operation may be performed.

Further, the method of changing the engine command value when registering the correction table is not limited to the method described in the embodiment.

〔The invention's effect〕

As described above, according to the present invention, when the work is stopped, the engine is actually driven, the correspondence between the command value of the engine speed and the actual value is registered, and then the correspondence is used during the actual work. Since the command value is corrected, the engine can be accurately driven according to the command value even if the engine parts have manufacturing variations or aging. Therefore, the driver does not feel discomfort, and accurate pump absorption torque control can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 and 3 are flowcharts for explaining the operation of the embodiment,
FIG. 4 is a diagram illustrating a correction table of an engine rotation command value, FIGS. 5 and 6 are diagrams for explaining a modification of the embodiment, and FIG. 7 is a diagram illustrating an output characteristic of an engine and a pump absorption torque characteristic. FIG. DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Fuel injection pump, 3 ... All speed governor, 4 ... Control lever, 5 ... Governor motor, 6 ... Sensor, 7 ... Throttle amount setting device, 8 ... Hydraulic pump, 10 …… Controller, 11… Operation valve, 12… Hydraulic actuator, 14… Operation lever,
15 ... Neutral detector, 16 ... Operation panel, 20 ...
Rotation sensor, SW1 ... Correction command value registration mode switch

Claims (5)

(57) [Claims] 1. An all-speed governor having a control lever drive device for variably driving a position of a control lever so that an engine output characteristic corresponding to an input target engine speed is selected, and a fuel injection amount by the all-speed governor. A diesel engine controlled by a diesel engine, a hydraulic pump driven by the output of the diesel engine, and a hydraulic actuator driven by hydraulic pressure supplied from the hydraulic pump. Neutral detection means for detecting that all are in a neutral state; diesel engine speed detection means for detecting the rotation speed of the diesel engine; and a detection signal from the neutral detection means, a plurality of different engines. First control means for sequentially inputting a rotation speed command value to the control lever driving device to actually drive the diesel engine and the all-speed governor in a no-load state; and in the actual driving state of the diesel engine, the plurality of different A detection output of the diesel engine rotation detecting means is sequentially taken in corresponding to the engine speed command value, and data indicating a correspondence between the engine speed command value and the actual engine speed is stored in a predetermined memory table. And a control means for: when operating the construction machine, designating, in the memory table, an actual engine speed having the same value as the target engine speed, and a diesel engine speed command value corresponding to the designated actual engine speed. From the memory table, and the read diesel engine speed command value Third control means for outputting the corrected target engine speed to the control lever drive device, and a diesel engine control device for a construction machine. 2. The construction according to claim 1, wherein said first control means sequentially inputs a plurality of different engine speed command values to said control lever drive device over the entire range of engine speed. Diesel engine control of the machine. 3. The control device according to claim 1, wherein the first control means sequentially inputs the control command to the control lever drive while increasing the plurality of different engine speed command values, and sequentially controls the control lever while decreasing the plurality of different engine speed command values. The second control means inputs the detection output of the diesel engine rotation detection means obtained when increasing the plurality of different engine speed command values, and the plurality of different engine speeds. 3. The method according to claim 1, further comprising: averaging a detection output of the diesel engine rotation detection means obtained when the command value is decreased, and storing the average value as an actual engine rotation speed in the memory table. Diesel engine control equipment for construction equipment. 4. The control lever drive device according to claim 1, wherein after a predetermined time has elapsed from the time when the detection signal is input from the neutral detection means, the first control means sequentially outputs a plurality of different engine speed command values. The diesel engine control device for a construction machine according to claim 1, wherein the input is input to the diesel engine. 5. An all-speed governor having a control lever driving device for variably driving a position of a control lever so that an engine output characteristic corresponding to an input target engine speed is selected, and a fuel injection amount by the all-speed governor. A diesel engine controlled by a diesel engine, a hydraulic pump driven by the output of the diesel engine, and a hydraulic actuator driven by hydraulic pressure supplied from the hydraulic pump. Neutral detecting means for detecting that all are in a neutral state, diesel engine speed detecting means for detecting the speed of the diesel engine, and operation switch means for instructing execution of the diesel engine correction command value registration mode When the execution of the diesel engine correction command value registration mode is instructed by the operation switch means and a detection signal is input from the neutral detection means, a plurality of different engine speed command values are sequentially input to the control lever drive device. First control means for actually driving the diesel engine and the all-speed governor in a no-load state; and in the actual driving state of the diesel engine, the diesel engine rotation corresponding to the plurality of different engine speed command values, respectively. Second control means for sequentially taking in the detection outputs of the detection means and storing data indicating the correspondence between the engine speed command value and the actual engine speed in a predetermined memory table; and The shaft engine rotation value of the same value as the rotation speed is stored in the memory table. And reads the diesel engine speed command value corresponding to the specified shaft engine speed value from the memory table, and uses the read diesel engine speed command value as a corrected target engine speed to the control lever drive device. And a third control means for outputting. A diesel engine control device for a construction machine, comprising: