JP2008232137A - Engine accelerator control method and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine accelerator control method which realizes increased gas mileage and low noise at a light load and which can make each profile of a high output compatible with each other at a heavy load. <P>SOLUTION: When a set accelerator position (100%) set by an accelerator dial is higher than a standard accelerator position (80%) set as an accelerator position at the time of a light load, the switching control of the engine accelerator is performed by the following method. (1) The engine accelerator is automatically set at 80% at the time of engine start. (2) When a shift to a heavy-load state is made, the engine accelerator is automatically set at 100%, thus high output can be obtained. (3) When a shift from the state (2) to a light-load state is made, the engine accelerator is again automatically set at 80%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine accelerator control method and apparatus capable of setting an engine rotation speed at a plurality of stages of accelerator positions.

FIG. 4 shows a plurality of engine speed-output characteristics with different engine speeds (hereinafter referred to as “speeds”) at no load, which are set at a plurality of accelerator positions by the accelerator position setting device. As shown by a plurality of straight line parts in FIG. 4, the engine characteristic that can be controlled by the governor is generally a plus loop characteristic in which the engine speed decreases as the power increases. Since the load fluctuates during actual work, the engine speed changes along the droop curve as shown by the arrow. A plurality of droop curves are set according to the target rotational speed input from the accelerator dial (see, for example, Patent Document 1).
Japanese Patent No. 3765317 (5th page, FIG. 5)

  In this engine speed-output characteristic, since the engine speed is high at low loads, the fuel efficiency and noise are high, and the engine speed is low at high loads. This is different from characteristics desired for a machine such as a work machine.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an engine accelerator control method and apparatus that achieve both low fuel consumption and low noise at low loads and high output characteristics at high loads. To do.

  The invention described in claim 1 is an engine accelerator control method for setting a plurality of engine rotational speed-output characteristics with different engine rotational speeds at no load at a plurality of stages of accelerator positions, wherein the set accelerator position is set. To determine whether the engine load is in the low load range or the high load range, and if the set accelerator position is higher than a certain reference accelerator position and the load is in the low load range, the engine actually used This is an engine accelerator control method in which the accelerator is controlled to the reference accelerator position, and when the set accelerator position is higher than the reference accelerator position and the load is in a high load range, the engine accelerator is controlled to the set accelerator position.

  The invention described in claim 2 is an engine accelerator control method for setting a plurality of engine rotational speed-output characteristics with different engine rotational speeds when there is no load at a plurality of accelerator positions, wherein the set accelerator position is set. , Detecting whether the engine load is in a low load region or a high load region, and operating a control valve that controls the working fluid discharged from the pump driven by the engine and supplied to the fluid pressure actuator Determine whether or not there is input from the actuator, and if the set accelerator position is higher than a certain reference accelerator position and there is no input from the actuator or the load is in the low load range, the actual engine accelerator to be used Control to the reference accelerator position, the set accelerator position is higher than the reference accelerator position, A is there input work unit, and when the load is high load region is an engine acceleration control method for controlling an engine acceleration to set the accelerator position.

  According to a third aspect of the present invention, there is provided an accelerator position setter for setting a plurality of engine rotation speed-output characteristics with different engine rotation speeds at no load at a plurality of stages of an accelerator position, and an engine load in a low load range. Load range determination signal output means for outputting a determination signal for determining whether the load is in the high load range, and a determination output from the load range determination signal output means by detecting the set accelerator position set by the accelerator position setter The signal determines whether the engine load is in the low load range or the high load range. If the set accelerator position is higher than a certain reference accelerator position and the load is in the low load range, the engine accelerator to be used is selected. Control to the reference accelerator position, the set accelerator position is higher than the reference accelerator position, and the load is in the high load range. If an engine accelerator controller with a controller for controlling the engine acceleration to set the accelerator position.

  According to a fourth aspect of the present invention, there is provided an accelerator position setter for setting a plurality of engine rotational speed-output characteristics with different engine rotational speeds at no load at a plurality of accelerator positions, and an engine load in a low load range. A load region determination signal output means for outputting a determination signal for determining whether there is a high load region, a control valve for controlling a working fluid discharged from a pump driven by the engine and supplied to a fluid pressure actuator, and a control Detects the set accelerator position set by the actuator that operates the valve and the accelerator position setter, and determines whether the engine load is in the low load range or the high load range based on the determination signal output from the load range determination signal output means It is determined whether there is an input from the actuator that operates the control valve, and the set accelerator position is consistent. The engine accelerator that is actually used is controlled to the reference accelerator position and the set accelerator position is higher than the reference accelerator position when either the actuator input is not input or the load is in the low load range. The engine accelerator control device includes a controller that controls the engine accelerator to a set accelerator position when the operation unit is input and the load is in a high load range.

  According to a fifth aspect of the present invention, in the engine accelerator control device according to the third or fourth aspect, the load range determination signal output means detects the pump discharge pressure of the working fluid discharged from the pump driven by the engine. When the controller is equipped with a sensor and the controller determines that the load is low, the engine load is high when the pump discharge pressure detected by the pressure sensor or its moving average is greater than or equal to the threshold for shifting to the high load range. When it is determined that the engine has moved to the high range, and the high load range is determined, the pump discharge pressure detected by the pressure sensor or its moving average is less than or equal to the threshold for shifting to the low load range that is different from the threshold for shifting to the high load range. When the state continues for an arbitrarily set time, it is determined that the engine load has shifted to the low load range.

  The invention described in claim 6 is a pressure in which the load region determination signal output means in the engine accelerator control device according to claim 3 or 4 detects the pump discharge pressure of the working fluid discharged from the pump driven by the engine. When the controller is determined to be in the low load range, the pump discharge pressure detected by the pressure sensor or its moving average is a threshold for shifting to the high load range. If the engine speed detected by the speed sensor or its moving average is below the speed threshold for shifting to the high load range, it is determined that the engine load has shifted to the high load range, and the load is determined to be high. When the pump discharge pressure detected by the pressure sensor or its moving average is lower than the threshold for shifting to the high load range, which is different from the threshold for shifting to the high load range, , When the duration set arbitrarily, the load of the engine is one which determines that moved to the low load region.

  According to a seventh aspect of the present invention, in the engine accelerator control device according to the sixth aspect of the present invention, the speed threshold value for shifting the engine rotation speed or its moving average to a high load range is set when the load application speed is high or low. If the engine rotation speed detected by the speed sensor or its moving average is below the speed threshold value continues for an arbitrarily set time, the controller It is determined that the load has moved to the high load range.

  According to the first aspect of the present invention, even when the set accelerator position is higher than a certain reference accelerator position, when the engine load is in a low load range, the engine accelerator is set to a reference accelerator position lower than the set accelerator position. Therefore, the engine control characteristics with low fuel consumption and low noise can be realized at low load, and when the set accelerator position is higher than the reference accelerator position and the engine load is in the high load range, the engine accelerator is used as the reference accelerator. Since the accelerator position is set higher than the position, high output engine control characteristics can be realized at high loads.

  According to the invention described in claim 2, even when the set accelerator position is higher than a certain reference accelerator position, if there is no input from the operating device or the engine load is in a low load range, the engine accelerator is Since the reference accelerator position is set lower than the set accelerator position, engine control characteristics with low fuel consumption and low noise can be realized when the fluid pressure actuator is not operated or under low load, and the set accelerator position is higher than the reference accelerator position. When the actuator input is present and the engine load is in a high load range, the engine accelerator is controlled to a set accelerator position higher than the reference accelerator position, so the actuator operates the fluid pressure actuator via the control valve, and When the load is high, high output engine control characteristics can be realized. .

  According to the third aspect of the present invention, even if the set accelerator position set by the accelerator position setter is higher than a certain reference accelerator position, the engine position is determined based on the determination signal output from the load range determination signal output means. The controller that determines that the load is in the low load range sets the engine accelerator to a reference accelerator position that is lower than the set accelerator position, so that it can realize engine control characteristics with low fuel consumption and low noise when the load is low. The controller that determines that the position is higher than the reference accelerator position and the engine load is in the high load range controls the engine accelerator to a set accelerator position that is higher than the reference accelerator position, thus realizing high output engine control characteristics at high loads. it can. Further, since the control is to select the reference accelerator position and the set accelerator position, the control system can be configured simply.

  According to the invention described in claim 4, even if the set accelerator position set by the accelerator position setting device is higher than a certain reference accelerator position, there is no input from the operating device, or from the load region determination signal output means. The controller that determines that the engine load is in the low load range based on the output determination signal sets the engine accelerator to a reference accelerator position lower than the set accelerator position, so it is low when the fluid pressure actuator is not operated or when the load is low. Engine control characteristics with low fuel consumption and low noise can be realized, and the controller that has determined that the set accelerator position is higher than the reference accelerator position, that there is an actuator input, and that the engine load is in the high load range is based on the engine accelerator. Control to a set accelerator position higher than the accelerator position In, it operates the hydraulic actuator through the control valve by the operation unit, and when a high load, can be realized engine control characteristics of high output. Further, since the control is to select the reference accelerator position and the set accelerator position, the control system can be configured simply.

  According to the fifth aspect of the present invention, when it is determined that the load is low, the engine is discharged when the pump discharge pressure detected by the pressure sensor or its moving average is equal to or higher than the threshold for shifting to the high load. When it is determined that the load has moved to the high load range and is determined to be the high load range, when the pump discharge pressure or its moving average is below the threshold value for shifting to the low load range continues for a set time, By determining that the engine load has shifted to the low load range, it is possible to easily determine whether the load of the engine has shifted to the high or low range.

  According to the invention described in claim 6, when it is determined that the load is low, the pump discharge pressure detected by the pressure sensor or its moving average is equal to or higher than the threshold for high load shift, and the speed When the engine rotation speed detected by the sensor or its moving average is equal to or lower than the speed threshold for shifting to the high load range, it is determined that the engine load has moved to the high load range, and when it is determined to be the high load range, When the pump discharge pressure or its moving average is below the threshold for low load range transition for a set time, it is determined that the engine load has shifted to the low load range. Can be sure.

  According to the invention described in claim 7, the speed threshold value for shifting the engine speed or its moving average to a high load range is set higher than the engine speed that coincides when the load application speed is fast and slow. The controller determines that the engine load has shifted to a high load range if the speed is below the speed threshold for a set time, so it increases gently even when the load suddenly increases and shifts to a heavy load. Thus, even when the load is shifted to a heavy load, that is, even when the engine speed changes suddenly or gradually changes, it can be determined that the load is accurately heavy.

  Hereinafter, the present invention will be described in detail with reference to an embodiment shown in FIGS.

  FIG. 1 shows an outline of an engine accelerator control device. A hydraulic excavator 11 as a work machine includes a hydraulic oil tank 12 as a working fluid, an engine 13, and a plurality of pumps 14 (drive pumps) driven by the engine 13. 14a and idle pump 14b), a control valve 15 for controlling hydraulic oil discharged from these pumps 14 and supplied to a hydraulic motor Hm as a fluid pressure actuator and hydraulic cylinder Hc, and the like are mounted.

  The engine 13 is provided with a speed control governor 16 such as an electronic governor or a mechanical governor that can be electrically controlled by a control motor, and an engine controller 17e for fuel injection control is connected to the governor 16, The engine controller 17e is connected to a machine controller 17m for calculating a command value of the engine rotation speed (hereinafter, the rotation speed is referred to as “the number of rotations”). The engine controller 17e and the machine controller 17m constitute a controller 17.

  The engine 13 is provided with a speed sensor 21 for detecting the engine speed for fuel injection control and a speed sensor 22 for detecting the engine speed for calculating the engine speed command value. However, it is connected to the engine controller 17e and the airframe controller 17m.

  The airframe controller 17m is connected to an operation lever 23 as an operating device for inputting a pilot pressure operation signal to the control valve 15 via a pressure switch 24 for converting the pilot pressure operation signal into an electric signal. Accelerator dial 25 is connected as an accelerator position setter that sets multiple engine speed-output characteristics at multiple stages of accelerator position, and pumps of hydraulic oil discharged from multiple pumps 14 A plurality of pressure sensors 26 and 27 for detecting the discharge pressure are connected.

  At least these pressure sensors 26 and 27 constitute a load region determination signal output means 28 that outputs a determination signal for determining whether the load of the engine 13 is in a low load region or a high load region. In this case, the controller 17, particularly the machine controller 17m, determines that the load of the engine 13 is in the high load region when the pump discharge pressure detected by the pressure sensors 26 and 27 or the moving average thereof is equal to or greater than a predetermined threshold. . The moving average is an average value obtained by dividing the sum of a predetermined number of measured values in the past past by the number, and is obtained by smoothing a fine uneven waveform of the measured values.

  In addition to the pressure sensors 26 and 27, the load region determination signal output means 28 may include a speed sensor 22 that detects the engine speed. In this case, the airframe controller 17m determines that the pump discharge pressure detected by the pressure sensors 26 and 27 or its moving average is equal to or greater than a predetermined threshold, and the engine speed detected by the speed sensor 22 or its moving average is a predetermined value. When the speed is equal to or less than the speed threshold, it is determined that the load of the engine 13 is in the high load range.

  At this time, as shown in FIG. 5, when setting the engine speed or the moving average speed threshold value in the airframe controller 17m, the engine speed coincides between the case where the load application speed is fast and the case where the load is slow. The low speed threshold value A and the high speed threshold value B are set, and the aircraft controller 17m rapidly starts the engine 13 load from the state in which the engine speed detected by the speed sensor 22 or its moving average is equal to or less than the speed threshold value A. It can be determined that the engine has increased and entered the high load range, and the engine speed detected by the speed sensor 22 or its moving average is less than or equal to the speed threshold B. It can also be determined that the vehicle has entered a high load range.

  As shown in FIG. 5, even when the same amount of load is applied, when the load application speed is high, the fluctuation amount of the engine speed increases, whereas when the input speed is low, the engine It is a general characteristic of the engine that the amount of fluctuation in the rotational speed is small.

  Therefore, if the speed threshold A for determining the load of the engine speed is set in accordance with the case where the load application speed is high, if the input speed is low, it is determined that the load is light even if the same amount of load is applied. May be.

  Therefore, the reference for load determination is set to a speed threshold B higher than the engine speed that coincides between the case where the load application speed is high and the case where the load application speed is low rather than the speed threshold A, and the state below this speed threshold B is It is desirable to set the duration. Hereinafter, the case where the engine speed detected by the speed sensor 22 or the moving average thereof is equal to or lower than the speed threshold means a case where the state equal to or lower than the speed threshold B continues for an arbitrarily set time.

  The controller 17 detects the set accelerator position set by the accelerator dial 25, and based on the determination signal output from the load region determination signal output means 28, the load of the engine 13 is in the low load region or the high load region. Even if the set accelerator position is higher than a certain reference accelerator position (80%), if the load is in the low load range, the engine accelerator actually used is controlled to the reference accelerator position (80%), When the set accelerator position is higher than the reference accelerator position (80%) and the load is in the high load range, the engine accelerator is controlled to the set accelerator position.

  Further, the controller 17 detects the set accelerator position set by the accelerator dial 25, and based on the determination signal output from the load region determination signal output means 28, the load of the engine 13 is in a low load region or a high load region. If there is no operation lever input even if the set accelerator position is higher than a certain reference accelerator position (80%) In one of the cases where the load is in the low load range, the engine accelerator actually used is controlled to the reference accelerator position (80%), the set accelerator position is higher than the reference accelerator position (80%), and there is an operation lever input. If the load is in the high load range, the function to control the engine accelerator to the set accelerator position Eteiru.

  Next, the control method of the embodiment shown in FIG. 1 will be described based on FIG.

  If the set accelerator position X (here, X = 100%) set by the accelerator dial 25 is higher than the reference accelerator position A (here, A = 80%) set as the accelerator position at low load, The engine accelerator is switched and controlled by this method.

(1) When the engine is started, the engine accelerator is automatically set to 80% to operate with low fuel consumption and low noise.

(2) When the load becomes high, the engine accelerator is automatically set to 100% and high output is obtained.

(3) When the load is reduced from the state (2) above, the engine accelerator is automatically set to 80% again.

  Here, the level of the load is determined by the controller 17 based on the determination signal output from the load region determination signal output means 28, and (a) pump discharge pressure (a plurality of pumps 14 such as the drive pump 14a and the idle pump 14b) In some cases, the average pressure or maximum value of these pumps 14), or the moving average of these pump discharge pressures, and (b) the engine speed or the moving average of the engine speed, in combination Determine.

  For example, if the average pressure or the moving average of the pump 14 detected by the pressure sensors 26 and 27 is equal to or higher than the threshold for shifting to the high load range, it is determined that the load is in the high load range. Alternatively, the average pressure of the pump 14 detected by the pressure sensors 26 and 27 or the moving average thereof is equal to or higher than the threshold for shifting to the high load range, and the engine speed detected by the speed sensor 22 or the moving average thereof is When the speed threshold value A or B for shifting to the high load range shown in FIG. When the load is lower than the speed threshold A, it is limited to the case where the load changes rapidly. However, when the load is lower than the speed threshold B, not only when the load changes rapidly, but also when the load changes slowly, the load is high. Judge that there is.

  Furthermore, the state where the average pressure of the pump 14 detected by the pressure sensors 26 and 27 or the moving average thereof is equal to or lower than the low load range shift threshold value different from the high load range shift threshold value has continued for an arbitrarily set time. In this case, it is determined that the load of the engine 13 is in the low load range. Alternatively, the state in which the average pressure of the pump 14 detected by the pressure sensors 26 and 27 or the moving average thereof is equal to or lower than the threshold for shifting to the low load range different from the threshold for shifting to the high load range has continued for an arbitrarily set time. In this case, it is determined that the load of the engine 13 is in the low load range.

  Next, a control example of the engine accelerator control method according to the present invention will be described with reference to the flowchart shown in FIG. 2 and the characteristic diagram shown in FIG.

(Step S1)
The controller 17 detects the set accelerator position (accelerator dial position) set by the accelerator dial 25.

(Step S2)
The controller 17 determines whether or not the set accelerator position is higher than a certain reference accelerator position (80%).

(Step S3)
When the set accelerator position is lower than a certain reference accelerator position (80%), the controller 17 controls the engine accelerator to an accelerator value (for example, 60%) corresponding to the set accelerator position (accelerator dial position).

(Step S4)
When the set accelerator position set with the accelerator dial 25 is higher than a certain reference accelerator position (80%) (for example, 100%), the controller 17 first selects the engine accelerator to be used as a reference as shown in FIG. Control to the accelerator position (80%).

(Step S5)
The controller 17 detects the pump discharge pressure (average pressure or maximum value) of the drive pump 14a and the idle pump 14b detected by the pressure sensors 26 and 27 of the load region determination signal output means 28, and the engine speed detected by the speed sensor 22. Alternatively, a load average of the engine 13 is calculated by calculating a moving average of the engine speed.

(Step S6)
The controller 17 determines whether or not the load on the engine 13 has shifted from the low load range to the high load range. For example, when it is determined that the load is low, the load of the engine 13 is high when the pump discharge pressure detected by the pressure sensors 26 and 27 or its moving average is equal to or higher than the threshold for shifting to the high load. It is determined that it has moved to. Alternatively, when it is determined that the engine is in the low load region, the pump discharge pressure detected by the pressure sensors 26 and 27 or the moving average thereof is equal to or higher than the threshold for shifting to the high load region, and the engine detected by the speed sensor 22 When the rotational speed or the moving average is equal to or lower than the speed threshold value for shifting to the high load range, it is determined that the load of the engine 13 has shifted to the high load range.

  When the load remains in the low load range (NO in step S6), the process returns to step S4, and the actually used engine accelerator is maintained at the reference accelerator position (80%).

(Step S7)
When the load has shifted to a high load range (YES in step S6), the controller 17 sets the engine accelerator to an accelerator value corresponding to the set accelerator position (accelerator dial position 100%) as shown in FIG. Control.

(Step S8)
The controller 17 calculates the pump discharge pressure (average pressure or maximum value) of the drive pump 14a and the idle pump 14b detected by the pressure sensors 26 and 27, the engine speed detected by the speed sensor 22, or the moving average of the engine speed. The load state of the engine 13 is calculated by calculation. At the same time, the input state from the operation lever 23 for pilot-operating the control valve 15 is processed.

(Step S9)
The controller 17 determines whether or not there is an input from the operation lever 23 for operating the control valve 15. If there is no operation lever input, the controller 17 returns to step S4 and controls the actually used engine accelerator to the reference accelerator position (80%). If there is an operation lever input, the process proceeds to step S10.

(Step S10)
The controller 17 determines whether or not the load of the engine 13 has shifted from the high load range to the low load range based on the determination signal output from the load range determination signal output means 28. For example, when it is determined as the high load range, the pump discharge pressure detected by the pressure sensors 26 and 27 or the moving average thereof is lower than the low load range shift threshold value different from the high load range shift threshold value. However, when it continues for the time set arbitrarily, it determines with the load of the engine 13 having moved to the low load region. Alternatively, when it is determined as the high load range, the pump discharge pressure detected by the pressure sensors 26 and 27 or the moving average thereof is not more than the threshold for shifting to the high load range and is below the threshold for shifting to the low load range However, when it continues for the time set arbitrarily, it determines with the load of the engine 13 having moved to the low load region.

  If the load has shifted to the low load range, the process returns to step S4 to control the actually used engine accelerator to the reference accelerator position (80%). If the load remains in the high load range, the flow proceeds to step S7. Returning, the engine accelerator is controlled to the accelerator value corresponding to the set accelerator position (accelerator dial position 100%).

  Next, effects of the illustrated embodiment will be described.

  Even if the set accelerator position set by the accelerator dial 25 is higher than a certain reference accelerator position (80%), the load of the engine 13 is in the low load range based on the determination signal output from the load range determination signal output means 28. The controller 17 that has determined that the engine accelerator is set to a reference accelerator position (80%) lower than the set accelerator position, so it is possible to realize engine control characteristics with low fuel consumption and low noise at low loads, and the set accelerator position is The controller 17 that has determined that the load of the engine 13 is in the high load range even if it is higher than the reference accelerator position (80%) controls the engine accelerator to a set accelerator position higher than the reference accelerator position (80%). High output engine control characteristics can be realized under load. Further, since the control is to select the reference accelerator position and the set accelerator position, the control system can be configured simply.

  Even if the set accelerator position set with the accelerator dial 25 is higher than a certain reference accelerator position (80%), there is no input from the operation lever 23 or based on the determination signal output from the load range determination signal output means 28. The controller 17 that has determined that the load of the engine 13 is in the low load range sets the engine accelerator to a reference accelerator position (80%) lower than the set accelerator position, so the fluid pressure actuators (hydraulic motor Hm and hydraulic cylinder Hc) Engine control characteristics with low fuel consumption and low noise during non-operation and low load can be achieved. Even if the set accelerator position is higher than the standard accelerator position (80%), there is an operation lever input and the engine 13 load is high. The controller 17 that has determined that the engine is in the high load range uses the engine accelerator as a reference accelerator position. The accelerator position is higher than the engine (80%), so the hydraulic lever (hydraulic motor Hm and hydraulic cylinder Hc) is operated by the control lever 15 via the control valve 15 and the output is high when the load is high. The engine control characteristics can be realized. Further, since the control is to select the reference accelerator position and the set accelerator position, the control system can be configured simply.

  When it is determined that the engine is in the low load range, the load on the engine 13 moves to the high load range when the pump discharge pressure detected by the pressure sensors 26 and 27 or its moving average is equal to or higher than the threshold for shifting to the high load range. If the pump discharge pressure or the moving average of the pump discharge pressure or its moving average is below the threshold for shifting to the low load range continues for a set time, the load on the engine 13 is low. Therefore, it is possible to easily determine whether the controller 17 shifts the high / low range of the load.

  When it is determined that the engine is in the low load range, the pump discharge pressure detected by the pressure sensors 26 and 27 or its moving average is equal to or higher than the threshold for shifting to the high load range, and the engine detected by the speed sensors 21 and 22 When the rotational speed or its moving average is equal to or lower than the speed threshold for shifting to the high load range, it is determined that the load of the engine 13 has shifted to the high load range. By determining that the load on the engine 13 has moved to the low load range when the moving average is below the threshold for low load range transition for a set time, the controller 17 reliably determines the load transition to the low load range. it can.

  In particular, the speed threshold B for shifting the engine speed or its moving average to a high load range is set to be higher than the engine speed that matches when the load application speed is fast and slow, and the aircraft controller 17m If the state below the threshold B continues for an arbitrarily set time, it is determined that the load on the engine 13 has shifted to a high load range, so even if the load suddenly increases and shifts to a heavy load, the load increases gently. Even when the engine is shifted to a heavy load, that is, even when the engine speed changes abruptly or slowly, it can be accurately determined that the load is heavy.

  In this way, as shown in FIG. 3, the engine accelerator can be automatically switched to a low position (80%) in the low load range and to a high position (100%) in the high load range.

  The present invention is applicable when the no-load engine speed is higher than the rated engine speed, and when not applicable, the accelerator is set according to the accelerator dial position.

  The present invention is applicable to an engine accelerator control method and apparatus for a work machine or the like in which the load of the engine 13 varies.

It is a block diagram which shows one Embodiment of the engine accelerator control apparatus which concerns on this invention. It is a flowchart which shows one control example of the engine accelerator control method which concerns on this invention. It is a characteristic view which shows the engine speed-output characteristic of a control apparatus and a control method same as the above. It is a characteristic view which shows the conventional engine speed-output characteristic. It is a characteristic view which shows the change of an engine speed in relation to a threshold value.

Explanation of symbols

13 engine
14 Pump
15 Control valve
17 Controller
22 Speed sensor
23 Operation lever as a controller
25 Accelerator dial as accelerator position setter
26, 27 Pressure sensor
28 Load range judgment signal output means
Hm, Hc Hydraulic motors and hydraulic cylinders as fluid pressure actuators

Claims (7)

An engine accelerator control method for setting a plurality of engine rotational speed-output characteristics with different engine rotational speeds at the time of no load at a plurality of accelerator positions,
Detects the set accelerator position that has been set,
Determine whether the engine load is in the low or high load range,
When the set accelerator position is higher than a certain reference accelerator position and the load is in the low load range, the actual engine accelerator used is controlled to the reference accelerator position,
An engine accelerator control method comprising: controlling an engine accelerator to a set accelerator position when a set accelerator position is higher than a reference accelerator position and a load is in a high load range. An engine accelerator control method for setting a plurality of engine rotational speed-output characteristics with different engine rotational speeds at the time of no load at a plurality of accelerator positions,
Detects the set accelerator position that has been set,
Determine whether the engine load is in the low or high load range,
Determining whether or not there is an input from an operating device that operates a control valve that controls a working fluid discharged from a pump driven by an engine and supplied to a fluid pressure actuator;
When the set accelerator position is higher than a certain reference accelerator position and there is no actuator input or the load is in the low load range, the actual engine accelerator used is controlled to the reference accelerator position.
An engine accelerator control method comprising: controlling an engine accelerator to a set accelerator position when a set accelerator position is higher than a reference accelerator position, an operation device is input, and a load is in a high load range. An accelerator position setter for setting a plurality of engine rotation speed-output characteristics with different engine rotation speeds at no load, and a plurality of accelerator positions;
Load range determination signal output means for outputting a determination signal for determining whether the engine load is in a low load range or a high load range;
Detects the set accelerator position set by the accelerator position setting device, determines whether the engine load is in the low load range or the high load range based on the determination signal output from the load range determination signal output means, and sets the accelerator If the position is higher than a certain reference accelerator position and the load is in the low load range, the actual engine accelerator used is controlled to the reference accelerator position, the set accelerator position is higher than the reference accelerator position, and the load is in the high load range. And a controller for controlling the engine accelerator to the set accelerator position. An accelerator position setter for setting a plurality of engine rotation speed-output characteristics with different engine rotation speeds at no load, and a plurality of accelerator positions;
Load range determination signal output means for outputting a determination signal for determining whether the engine load is in a low load range or a high load range;
A control valve for controlling the working fluid discharged from the pump driven by the engine and supplied to the fluid pressure actuator;
An actuator for operating the control valve;
The set accelerator position set by the accelerator position setter is detected, and the control valve determines whether the engine load is in the low load range or the high load range based on the determination signal output from the load range determination signal output means. Determine whether or not there is an input from the actuator that operates the actuator, and if the set accelerator position is higher than a certain reference accelerator position and there is no actuator input or the load is in the low load range, it is actually used A controller that controls the engine accelerator to the set accelerator position when the engine accelerator is controlled to the reference accelerator position, the set accelerator position is higher than the reference accelerator position, the actuator is input, and the load is in the high load range. An engine accelerator control device comprising: Load range determination signal output means,
A pressure sensor for detecting the pump discharge pressure of the working fluid discharged from the pump driven by the engine;
The controller
When it is determined to be in the low load range, it is determined that the engine load has shifted to the high load range when the pump discharge pressure detected by the pressure sensor or its moving average is equal to or higher than the threshold for shifting to the high load range,
When it is determined as a high load range, the pump discharge pressure detected by the pressure sensor or its moving average is set to a state where the low load range shift threshold value is different from the high load range shift threshold value. 5. The engine accelerator control device according to claim 3, wherein the engine accelerator control unit determines that the engine load has shifted to a low load region when the engine load continues for a predetermined period of time. Load range determination signal output means,
A pressure sensor for detecting a pump discharge pressure of a working fluid discharged from a pump driven by the engine;
A speed sensor for detecting the engine speed,
The controller
When the low load range is determined, the pump discharge pressure detected by the pressure sensor or its moving average is equal to or higher than the threshold for shifting to the high load range, and the engine speed detected by the speed sensor or its moving average Is below the speed threshold for shifting to the high load range, it is determined that the engine load has shifted to the high load range,
When it is determined as a high load range, the pump discharge pressure detected by the pressure sensor or its moving average is set to a state where the low load range shift threshold value is different from the high load range shift threshold value. 5. The engine accelerator control device according to claim 3, wherein the engine accelerator control unit determines that the engine load has shifted to a low load region when the engine load continues for a predetermined period of time. The speed threshold for shifting the engine speed or its moving average to a high load range is set higher than the engine speed that matches when the load application speed is fast and slow,
The controller shall determine that the engine load has moved to the high load range when the engine speed detected by the speed sensor or its moving average is below the above speed threshold value continues for an arbitrarily set time. The engine accelerator control device according to claim 6.

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