JP5273661B2 - Engine accelerator control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine accelerator control method for properly shifting an engine accelerator according to the state of a load by determining the load in isochronous control. <P>SOLUTION: In the isochronous control of an engine mounted on a working machine, the state of the load on the engine is determined by the output values of the engine detected from the fuel injection state of the engine or the moving average thereof and the pump pressures of an oil which is discharged from a variable displacement main pump connected to the engine or the moving average thereof. When the load is in a heavy load region, an engine accelerator is controlled to a set accelerator position which is set by an accelerator dial. When the load state is not in the heavy load region, the engine accelerator is automatically shifted to an accelerator position which is lower than the set accelerator position. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an engine accelerator control method in an isochronous control type engine.

  When the accelerator dial position set by the accelerator dial is high, the engine accelerator is automatically shifted according to the load, achieving both low fuel consumption and low noise at light loads, and high output characteristics corresponding to heavy loads. There is an engine accelerator control method for performing control (see, for example, Patent Document 1).

  In the load determination in this case, in the droop control type engine as shown in FIG. 5, the engine speed can be detected and the engine output can be determined from the engine speed-engine output characteristic.

JP 2008-232137 A (first page, FIG. 3)

  However, the engine output can be determined from the engine speed-engine output characteristic only in the droop control, and a constant engine speed can be maintained even when the engine output changes due to a load as shown in FIG. It cannot be applied to isochronous control that can

  The present invention has been made in view of these points, and an object of the present invention is to provide an engine accelerator control method that performs load determination in isochronous control and appropriately shifts the engine accelerator in accordance with the load state.

According to the first aspect of the present invention, in isochronous control of an engine mounted on a work machine, an output value grasped from an engine fuel injection situation or a moving average thereof, and a variable displacement main pump connected to the engine The engine load status is determined based on the pump pressure discharged or its moving average. If the load status is in the heavy load range, the engine accelerator is controlled to the set accelerator position set by the accelerator dial, and the load status is heavy load. If it is not in the range, the engine accelerator is automatically shifted to a lower accelerator position than the set accelerator position, and when the load state changes from the non-heavy load range to the heavy load range, the engine accelerator is moved from the set accelerator position. Auto change from low accelerator position to set accelerator position Shift the engine accelerator at a higher output when shifting from a lower accelerator position to a higher accelerator position than when shifting the engine accelerator from a relatively higher accelerator position to a lower accelerator position. an engine acceleration control method Ru remembering hysteresis characteristics so.

According to the second aspect of the present invention, in isochronous control of an engine mounted on a work machine, an output value obtained from a pump pressure discharged from a variable displacement main pump connected to the engine and a pump displacement control position. Alternatively, the load state is determined based on the moving average and the pump pressure or the moving average. If the load state is a heavy load range, the engine accelerator is controlled to the set accelerator position set by the accelerator dial, and the load state is overloaded. If it is not in the load range, the engine accelerator is automatically shifted to a lower accelerator position than the set accelerator position. If the load changes from the non-heavy load range to the heavy load range, the engine accelerator is set to the set accelerator position. Set accelerator position from lower accelerator position Shift automatically, when shifting the engine accelerator from a lower accelerator position to a higher accelerator position than when shifting the engine accelerator from a higher accelerator position to a lower accelerator position. an engine acceleration control method Ru remembering hysteresis characteristic so as to.

Invention described in 請 Motomeko 3, in the engine accelerator control method according to claim 1 or 2, wherein the accelerator position lower than the set accelerator position, and is provided a plurality of stages.

According to the first aspect of the present invention, the load state is statically determined based on the output value obtained from the engine fuel injection situation or the moving average thereof, and the load state is dynamically determined based on the pump pressure or the moving average thereof. Therefore, even in engine isochronous control, it is possible to appropriately determine whether the load state is a heavy load range or not, and the engine accelerator is set to the set accelerator position or a lower accelerator position depending on the load state. Shifting to low fuel consumption and low noise during light loads, and high output during heavy loads. In particular, when shifting the engine accelerator to a relatively high accelerator position, rather than when shifting the engine accelerator to a relatively low accelerator position, it has a hysteresis characteristic to shift at a higher output, so the accelerator position is as low as possible Can be maintained, and the accelerator position can be switched smoothly.

According to the second aspect of the present invention, the load state is statically determined based on the output value obtained from the pump pressure and the pump displacement control position or the moving average thereof, and the load state is determined based on the pump pressure or the moving average thereof. Therefore, even in engine isochronous control, it is possible to properly determine whether the load state is a heavy load range or not, and set the engine accelerator according to the load state. By shifting the position appropriately, low fuel consumption and low noise can be achieved at light loads, and high output can be obtained at heavy loads. In particular, when shifting the engine accelerator to a relatively high accelerator position, rather than when shifting the engine accelerator to a relatively low accelerator position, it has a hysteresis characteristic to shift at a higher output, so the accelerator position is as low as possible Can be maintained, and the accelerator position can be switched smoothly.

According to the invention described in 請 Motomeko 3, by lower accelerator position than the set accelerator position it is provided a plurality of stages, since it can reduce the engine rotational speed difference of the accelerator position automatic shift control, influence on the operability, Variations in engine sound can be suppressed.

FIG. 5 is a characteristic diagram of engine speed-output characteristics showing an embodiment of an engine accelerator control method according to the present invention. It is a block diagram which shows one Embodiment of the engine accelerator control apparatus used for a control method same as the above. It is a flowchart which shows one control example of the control method same as the above. It is a characteristic view of an engine speed-output characteristic showing another embodiment of the control method. It is a characteristic view which shows general droop control by an engine speed-output characteristic. It is a characteristic figure which shows general isochronous control by an engine speed-output characteristic.

  Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS. 1 to 3 and another embodiment shown in FIG.

  FIG. 2 shows an outline of an engine accelerator control device. An engine 11 mounted on a work machine such as a hydraulic excavator and a plurality of variable displacement main pumps 12 (a drive pump 12a and an idle pump) driven by the engine 11 are shown. 12b).

  The engine 11 includes a rotational speed sensor 13 that detects an engine rotational speed (rotational speed) for fuel injection control, and a speed control governor 14 such as an electronic governor or a mechanical governor that can be electrically controlled by a control motor. The rotation speed sensor 13 and the governor 14 are connected to an engine controller 15 for fuel injection control.

  The variable displacement main pump 12 supplies hydraulic oil to a hydraulic actuator (hydraulic motor and hydraulic cylinder) that operates the work machine. The tilt angle position of the swash plate as a pump displacement variable means is determined as a pump displacement control position. Swash plate position sensors 16a and 16b to detect the pump discharge pressure, and pump pressure sensors 17a and 17b to detect the pump discharge pressure. These swash plate position sensors 16a and 16b and pump pressure sensors 17a and 17b are connected to the body controller 18. It is connected.

  The machine controller 18 includes an operation lever 19 that pilot-operates a control valve that controls a hydraulic actuator (hydraulic cylinder and hydraulic motor) of a work machine, and a plurality of engine speed-output characteristics having different engine speeds in a plurality of stages. The accelerator dial 20 set by the accelerator position is connected.

  The engine controller 15 and the body controller 18 are connected to exchange information with each other. The engine controller 15 and the body controller 18 are referred to as a controller 21.

  Among the controllers 21, the body controller 18 reads the set accelerator position set by the accelerator dial 20, takes in the engine fuel injection status from the engine controller 15 as load information, and swash plate position sensors 16a and 16b and the pump pressure sensor 17a. 17b, the pump swash plate position and pump pressure are taken as load information, and lever input presence / absence information is taken from the operation lever 19, and it is determined whether the load state is in the heavy load range or lower load range. , It has a function to automatically shift the accelerator position.

  The engine controller 15 receives the accelerator position determined by the airframe controller 18 and the engine speed obtained from the speed sensor 13, and controls the governor 14 to perform the isochronous control shown in FIG. A function for controlling the fuel injection amount and timing is provided.

  The memory of the body controller 18 stores an accelerator control table shown in Tables 1 and 2 below. The numbers in these tables are%.

  Table 1 shows an example in which the accelerator automatic shift control according to the load state is applied only in the high accelerator dial range where the set accelerator position (that is, the accelerator dial position) set by the accelerator dial 20 is 100% or 90%. Table 2 shows an example in which the accelerator automatic shift control according to the load state is applied in the entire region where the accelerator dial position is 100% to 10%.

  Next, the concept of the present engine accelerator control method will be described with reference to the engine characteristic diagram shown in FIG.

  When the set accelerator position (accelerator dial position) is 100%, the accelerator position is automatically set to 90% when the engine is started, and the engine is operated with low fuel consumption and low noise. When the load state becomes a heavy load state, the accelerator position is automatically set to 100% so as to obtain a high output. When the heavy load state changes to a light load state with a low load, the accelerator position is automatically set to 90% again.

  In the determination of the load state at that time, the output value of the engine 11 (the engine fuel injection status obtained from the engine controller 15 or the pump pressure of the main pump 12 detected by the pump pressure sensors 17a and 17b and the swash plate position sensor 16a, (Predicted from information on the position of the pump swash plate detected by 16b) or its moving average) and pump pressure of the main pump 12 or its moving average (the average in the case of multiple pumps), or a combination thereof Thus, the body controller 18 determines the load state.

  Next, two engine accelerator control methods performed by the body controller 18 will be described.

  In the first engine accelerator control method, in the isochronous control of the engine 11 mounted on the work machine, the output value grasped from the engine fuel injection status or the moving average thereof, and the variable displacement main pump connected to the engine 11 12 determines the load state of the engine 11 based on the pump pressure discharged from the pump 12 or its moving average. If the load state is a heavy load range, the engine accelerator is controlled to the set accelerator position set by the accelerator dial 20, and the load When the state is not the heavy load range, the engine accelerator is automatically shifted to an accelerator position lower than the set accelerator position.

  The set accelerator position is a heavy load accelerator, and an accelerator position lower than the set accelerator position is a light load accelerator.

  When the output value is grasped from the fuel injection state of the engine 11, the engine controller 15 obtains the engine fuel injection information (fuel injection amount, timing, etc.) of the engine controller 15 from the engine controller 15. The pump pressure is detected by pump pressure sensors 17a and 17b installed in the pump discharge line of the main pump 12.

  The output value grasped from the engine fuel injection status is static load information, and the pump pressure discharged from the main pump 12 or its moving average is dynamic load information.

  The second engine accelerator control method is grasped from the pump pressure discharged from the variable displacement main pump 12 connected to the engine 11 and the pump displacement control position in isochronous control of the engine 11 mounted on the work machine. The load state is determined based on the output value or its moving average and the pump pressure or its moving average. If the load state is in the heavy load range, the engine accelerator is controlled to the set accelerator position set by the accelerator dial 20, and the load is When the state is not the heavy load range, the engine accelerator is automatically shifted to an accelerator position lower than the set accelerator position.

  The pump displacement control position is a pump swash plate position detected from a swash plate position sensor 16a, 16b such as a stroke sensor or an angle sensor installed with respect to the pump swash plate, a control signal of a swash plate control regulator, or the like. The output value obtained from the pump pressure and the pump swash plate position is a pump output that is a product of the pump pressure and the pump flow rate, and this is static load information.

  In these first and second engine accelerator control methods, a relatively high accelerator position from a relatively low accelerator position than when the engine accelerator is shifted from a relatively high accelerator position to a relatively low accelerator position. When shifting to, control is performed so as to provide hysteresis characteristics so as to shift at higher output. In this way, by providing hysteresis to the switching of the engine output characteristics, hunting can be prevented and switching can be facilitated, and the lowest possible accelerator can be maintained.

  Next, a specific example of load determination will be described.

(Specific example of load determination 1)
For example, if the moving average of the pump pressure of the main pump 12 is equal to or greater than the threshold (16 MPa) or the moving average of the output value is equal to or greater than the maximum output threshold (70%) for 3 seconds, the aircraft controller 18 is determined to be a heavy load. On the other hand, when the pump pressure moving average is less than the threshold (12 MPa) and the output value moving average is less than the maximum output threshold (50%) for 3 seconds, the airframe controller 18 is lightly loaded. Is determined.

(Specific example of load determination 2)
For example, the moving average of the pump pressure of the main pump 12 is not less than a threshold (16 MPa) and the moving average of the output value is not less than the threshold (75%) of the maximum output value, or the moving average of the output value is If the state exceeding the threshold (70%) of the maximum output value continues for 3 seconds, the aircraft controller 18 determines that the load is heavy. On the other hand, when the state where the moving average of the pump pressure is equal to or lower than the threshold (12 MPa) continues for 3 seconds, the body controller 18 determines that the load is light.

  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.

(Step 1)
The body controller 18 reads the set accelerator position set by the accelerator dial 20 (ie, the accelerator dial position).

(Step 2)
The body controller 18 determines whether or not control from the accelerator control table stored in the memory is necessary.

(Step 3)
If not necessary, the accelerator corresponding to each accelerator dial position set by the accelerator dial 20 is set.

(Step 4)
If control from the accelerator control table is necessary, first, the accelerator is set to a light load accelerator at each accelerator dial position.

(Step 5)
The machine controller 18 calculates the load state from the load information (information on the engine fuel injection state, pump pressure, pump swash plate position, etc.) and processes the input state from the operating lever 19 for operating the work machine.

(Step 6)
The presence / absence of input from the operation lever 19 is determined. If there is no operation lever input, the process returns to step 4 to maintain the light load accelerator state.

(Step 7)
When there is an operation lever input, the work machine is in operation, so the shift is made to the accelerator position corresponding to the load determination result.

  Next, effects of the embodiment shown in FIGS. 1 to 3 will be described.

  Since the load state is statically determined based on the output value obtained from the engine fuel injection status or its moving average, and the load state is dynamically determined based on the pump pressure or its moving average, even in isochronous control of the engine 11 It is possible to appropriately determine whether the load state is a heavy load range or not, and appropriately shift the engine accelerator to the set accelerator position or a lower accelerator position according to the load state, and it is fuel efficient at light load and Low noise can be achieved, and high output can be obtained during heavy loads.

  Since the load state is statically determined by the output value obtained from the pump pressure and pump displacement control position or its moving average, and the load state is dynamically determined by the pump pressure or its moving average, engine isochronous control The engine can be properly judged whether the load is in the heavy load range or not, and the engine accelerator is appropriately shifted to the set accelerator position or a lower accelerator position according to the load condition. Fuel consumption and low noise can be achieved, and high output can be obtained during heavy loads.

  When shifting to a relatively high accelerator position than when shifting the engine accelerator to a relatively low accelerator position, a hysteresis characteristic is provided to shift at a higher output so that the accelerator position is kept as low as possible. In addition, the accelerator position can be switched smoothly.

  Next, FIG. 4 shows another embodiment of the engine accelerator control method that has been developed in multiple stages.

  The embodiment shown in FIG. 4 is an engine accelerator control method in which a plurality of accelerator positions lower than the set accelerator position are provided. That is, the set accelerator position is a heavy load accelerator, and the accelerator positions lower than the set accelerator position are a medium load accelerator and a light load accelerator.

  Table 3 below shows an example of the accelerator control table in the case of multistage. The numerical values in Table 3 are%.

  Table 3 shows an example in which the present accelerator position automatic shift control is applied only in the high accelerator dial range where the accelerator dial position is set to 100% or 90%.

(Specific example 3 of load determination)
A specific example of load determination in the case of multi-stages shown in FIG. 4 will be described.

  If the moving average of the pump pressure of the main pump 12 exceeds the threshold (16MPa) or the moving average of the output value exceeds the maximum output threshold (70%) for 3 seconds, the fuselage controller 18 is in heavy load. It is determined that

  On the other hand, when operating with a light load accelerator, if the state in which the moving average of the output values is equal to or greater than the maximum output threshold (60%) continues for 3 seconds, it is determined that the airframe controller 18 has a medium load.

  When operating with a heavy load accelerator, if the moving average of the output values continues below the maximum output threshold (60%) for 3 seconds, the airframe controller 18 determines that the load is medium.

  When operating with an accelerator at medium load, if the moving average of the output values continues below the maximum output threshold (50%) for 3 seconds, the airframe controller 18 determines that the load is light.

  According to the control method shown in FIG. 4, since a plurality of accelerator positions lower than the set accelerator position are provided, the difference in engine speed of the accelerator automatic shift control can be reduced. It has the effect of suppressing fluctuations in sound.

  Although the embodiment shown in FIG. 4 has three stages, further multi-stages are possible if necessary.

  INDUSTRIAL APPLICABILITY The present invention can be used for an engine accelerator control method such as a work machine in which the engine load is likely to vary.

11 engine
12 Main pump
20 Accel dial

Claims (3)

In the isochronous control of the engine mounted on the work machine, the output value grasped from the engine fuel injection situation or its moving average, the pump pressure discharged from the variable capacity main pump connected to the engine or its moving average, To determine the engine load condition,
If the load state is a heavy load range, control the engine accelerator to the set accelerator position set by the accelerator dial,
When the load is not in the heavy load range, the engine accelerator is automatically shifted to a lower accelerator position than the set accelerator position ,
When the load state changes from the non-heavy load range to the heavy load range, the engine accelerator is automatically shifted from the accelerator position lower than the set accelerator position to the set accelerator position,
At that time, when shifting the engine accelerator from a relatively high accelerator position to a low accelerator position, when shifting from a relatively low accelerator position to a high accelerator position, a hysteresis characteristic is set so as to shift at a higher output. engine accelerator control method characterized by Ru remembering. In isochronous control of an engine mounted on a work machine, the pump pressure discharged from a variable displacement main pump connected to the engine and the output value obtained from the pump displacement control position or its moving average, and the pump pressure or its Judgment of load status by moving average,
If the load state is a heavy load range, control the engine accelerator to the set accelerator position set by the accelerator dial,
When the load is not in the heavy load range, the engine accelerator is automatically shifted to a lower accelerator position than the set accelerator position ,
When the load state changes from the non-heavy load range to the heavy load range, the engine accelerator is automatically shifted from the accelerator position lower than the set accelerator position to the set accelerator position,
At that time, when shifting the engine accelerator from a relatively high accelerator position to a low accelerator position, when shifting from a relatively low accelerator position to a high accelerator position, a hysteresis characteristic is set so as to shift at a higher output. engine accelerator control method characterized by Ru remembering. The engine accelerator control method according to claim 1 or 2 , wherein a plurality of accelerator positions lower than the set accelerator position are provided.

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