JPWO2012029426A1 - Industrial machine engine control apparatus and industrial machine engine speed control method - Google Patents

Abstract

For an industrial machine capable of executing an auto-decel function by discriminating a state in which work is not actually performed without using an additional switch, a sensor, or the like, and without requiring an operation by an operator. An engine control device and an industrial machine engine speed control method are provided. In an engine control device for an industrial machine that controls an engine that drives a hydraulic pump for supplying hydraulic pressure to a hydraulic device that is operated by hydraulic pressure, the engine rotational speed is set based on an instruction of the target rotational speed. The engine speed control means for controlling the engine so as to achieve the engine speed, the load detection means for detecting the control parameter correlated with the load on the engine, and whether or not the value of the control parameter is less than a predetermined reduction threshold And a rotational speed reduction means for reducing the engine rotational speed regardless of the instruction of the target rotational speed when the value of the control parameter becomes less than the reduction threshold value. [Selection] Figure 3

Description

  The present invention relates to an industrial machine engine control apparatus and an industrial machine engine speed control method. In particular, the present invention relates to an industrial machine engine control apparatus and an industrial machine engine speed control method capable of automatically reducing the engine speed while the industrial machine is not working.

  2. Description of the Related Art Conventionally, as an industrial machine represented by a construction machine, an agricultural machine, and the like, an engine, a hydraulic pump driven by the engine, and a hydraulic device including an actuator that is operated by hydraulic pressure supplied from the hydraulic pump are provided. Some are configured so that a predetermined operation can be performed by operation.

  The engine used in such an industrial machine has an engine speed (hereinafter referred to as “engine speed”) according to the content of the work by means of a speed adjusting means such as a speed lever and a speed adjusting dial and a speed setting device capable of inputting a target speed. This rotational speed is referred to as “appropriate rotational speed”), and the target rotational speed is set and used. When the engine is controlled in this way, the engine continues to run at an appropriate rotation speed set by the rotation speed adjusting means, the rotation speed setting device, etc. even when the work is not actually performed. There is a risk of deterioration of the sound and noise.

  For this reason, the operation position of the operation lever of the hydraulic device and the operation signals of the valves and actuators operated by the operation of the operation lever are detected by the control device (control unit) using a sensor or the like, and the operation is actually performed. In the case where it is determined that the engine speed has not been determined, a method for automatically controlling the actual engine speed to a low speed such as an idle speed is known regardless of the set target speed (hereinafter referred to as “this”). Such control is referred to as “auto-decel function”).

  Furthermore, not only the operation position of the operation lever and the operation signals of valves and actuators, but also an operation command for controlling the engine speed to a low speed and an operation command for controlling the engine speed according to the target speed instruction. The control device is configured to control the engine speed to a low speed regardless of the set target speed when the control device receives a command to control the engine speed to a low speed by using a switch to be selected and set. There is also a control device (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 8-21269 (full text, full figure)

  However, when the auto-decel function is executed, the control device determines that the work is not being performed by the operation position of the operation lever of the hydraulic device, the operation signal of the valve or actuator, the command from the switch, etc. It is necessary to additionally provide sensors, switches, etc. in the machine body. Therefore, there is a risk that the cost of the industrial machine is increased. Further, when the auto-decel function is executed as described above, an operation by the worker is essential, and there is a possibility that an extra burden is placed on the worker.

  In view of such problems, the inventor of the present invention is actually performing work based on control parameters correlated with the load on the engine among the control parameters when the engine speed is controlled by the control device. It has been found that such a problem can be solved by making it possible to determine whether or not the present invention has been completed, and the present invention has been completed. Therefore, the present invention can execute the auto-decel function by determining a state where work is not actually performed without using an additional switch, a sensor, or the like, and without requiring an operation by an operator. It is an object of the present invention to provide an industrial machine engine control device and an industrial machine engine speed control method.

  According to the present invention, in an industrial machine engine control device that controls an engine that drives a hydraulic pump for supplying hydraulic pressure to a hydraulic device that is operated by hydraulic pressure, an engine speed based on an instruction of a target speed The engine speed control means for controlling the engine so that the engine speed becomes the target engine speed and the control parameter correlated with the load applied to the engine are read to determine whether or not the value of the control parameter is less than a predetermined reduction threshold. And an engine speed control means for reducing the engine speed regardless of the instruction of the target speed when the value of the control parameter becomes less than the reduction threshold value. Can be provided to solve the above-mentioned problems.

  That is, according to the industrial machine engine control apparatus of the present invention, it is determined whether or not work is actually performed based on the value of the control parameter correlated with the load on the engine among the engine control parameters. Thus, the auto-decel function can be executed. Therefore, it is not necessary to provide an additional switch, sensor, or the like in the industrial machine, and an increase in cost can be suppressed. In addition, since it is not necessary to perform an operation by the worker to determine whether or not the work is in progress, the burden on the worker can be reduced. Furthermore, since the auto-decel function can be executed only by the engine control device, the auto-decel function can be executed by replacing the control device even in an existing industrial machine that does not have the auto-decel function. .

  Further, in configuring the industrial machine engine control device of the present invention, the rotation speed reduction means decreases the engine rotation speed when a predetermined time elapses while the value of the control parameter is less than the reduction threshold. It is preferable. By configuring the control device for an industrial machine engine according to the present invention in this way, the target rotational speed is not repeatedly switched according to fine fluctuations in the load applied to the engine, and a reduction in work efficiency can be prevented. .

  In configuring the industrial machine engine control apparatus of the present invention, it is preferable that the control parameter is a fuel injection amount or a required load on the engine. In the industrial machine engine control apparatus of the present invention, by using the fuel injection amount or the required load value for the engine as a control parameter, it is possible to accurately grasp the load on the engine and whether or not work is being performed. Can be accurately determined.

  In configuring the industrial machine engine control device of the present invention, the rotation speed reduction means determines whether or not the value of the control parameter is equal to or greater than a predetermined return threshold value after the engine rotation speed is decreased. Then, it is preferable to cancel the control for decreasing the engine speed when the value of the control parameter becomes equal to or greater than the return threshold value. By configuring the control device for an industrial machine engine of the present invention in this way, the engine speed can be quickly returned to the target speed when work is resumed, thereby preventing a reduction in work efficiency. it can.

  Further, in configuring the industrial machine engine control device of the present invention, the return threshold value is preferably larger than the decrease threshold value. In the industrial machine engine control apparatus according to the present invention, the return threshold value is set to a value larger than the threshold value for reducing the engine speed, so that the target engine speed can be set according to the minute fluctuation of the load on the engine. It is possible to prevent switching repeatedly.

  In configuring the industrial machine engine control apparatus of the present invention, the reduction threshold value is preferably a low load state value corresponding to the minimum control parameter value required for rotating the hydraulic pump. In the industrial machine engine control apparatus according to the present invention, the threshold value for reducing the engine speed is such a low load state value, so that it is possible to reliably determine the state in which the work is not performed and to determine the engine speed. Can be reduced.

  Further, when configuring the industrial machine engine control device of the present invention, a medium load state value greater than the low load state value is further set as the reduction threshold value, and the control parameter value is set to the medium load state. It is preferable that the setting value of the engine speed that is decreased when the value is less than the value be larger than the setting value of the engine speed that is decreased when the value of the control parameter is less than the low load state value. By configuring the control device for an industrial machine engine of the present invention in this way, the engine speed can be reduced according to the load required for the work even when the work is being performed. This is advantageous for reducing fuel consumption and noise.

  Further, in configuring the industrial machine engine control apparatus of the present invention, it is preferable to set the reduction threshold value or the return threshold value to a variable value according to the operating state of the engine. By configuring the control device for an industrial machine engine of the present invention in this way, a reduction threshold value or a return threshold value is set according to the pumping efficiency of the high-pressure pump provided in the fuel injection device, and work is performed. It is possible to accurately determine whether or not there is.

  In another aspect of the present invention, the engine is controlled such that the rotational speed of the engine that drives the hydraulic pump for supplying hydraulic pressure to the hydraulic device that operates by hydraulic pressure becomes the instructed target rotational speed. In the industrial machine engine speed control method to be performed, the control parameter correlated with the load applied to the engine is read to determine whether or not the value of the control parameter is less than a predetermined reduction threshold, and the value of the control parameter is An engine speed control method for an industrial machine, comprising: a step of decreasing the engine speed regardless of an instruction of a target speed when it becomes less than a reduction threshold value.

  That is, according to the industrial machine engine speed control method of the present invention, whether or not work is actually performed based on the value of the control parameter correlated with the load on the engine among the engine control parameters. It is possible to execute the auto-decel function after determination. Therefore, it is not necessary to provide an additional switch, sensor, or the like in the industrial machine, and an increase in cost can be suppressed. In addition, since it is not necessary to perform an operation by the worker to determine whether or not the work is in progress, the burden on the worker can be reduced.

  Further, in carrying out the industrial machine engine speed control method of the present invention, after reducing the engine speed, it is determined whether or not the value of the control parameter is equal to or higher than a predetermined return threshold, and control is performed. It is preferable to cancel the control for reducing the engine speed when the parameter value is equal to or greater than the return threshold. By implementing the engine speed control method for an industrial machine according to the present invention in this way, the engine speed can be quickly returned to the target speed when the operation is resumed, and a reduction in work efficiency is prevented. be able to.

It is a figure for demonstrating an example of the whole structure of an industrial machine. It is a block diagram which shows an example of a structure of the control apparatus (ECU) concerning 1st Embodiment. It is a figure for demonstrating the driving | running state of the engine controlled by the control apparatus concerning 1st Embodiment. It is a flowchart figure for demonstrating the control method of the engine speed concerning 1st Embodiment. It is a flowchart for demonstrating the calculation procedure of target fuel injection amount. It is a flowchart figure for demonstrating the procedure of fuel-injection control. It is a block diagram which shows an example of a structure of the control apparatus (ECU) concerning 2nd Embodiment. It is a figure for demonstrating the driving | running state of the engine controlled by the control apparatus concerning 2nd Embodiment. It is a flowchart for demonstrating the control method of the engine speed concerning 2nd Embodiment. It is a flowchart for demonstrating the control method of the engine speed concerning 2nd Embodiment. It is a block diagram which shows an example of a structure of the control apparatus (ECU) concerning 2nd Embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments relating to an industrial machine engine control apparatus and control method of the present invention will be specifically described below with reference to the drawings as appropriate. However, the following embodiment shows one aspect of the present invention and does not limit the present invention, and the embodiment can be arbitrarily changed within the scope of the present invention. In addition, what is attached | subjected with the same code | symbol in each figure has shown the same element, and description is abbreviate | omitted suitably.

[First Embodiment]
1. Overall Configuration of Industrial Machine First, an outline of the overall configuration of an industrial machine including the industrial machine engine control device of the present embodiment will be described.
FIG. 1 is a functional block diagram showing a part related to the present invention in the overall configuration of an industrial machine. This industrial machine includes an engine 11 provided with a fuel injection device 13 and a rotation speed sensor 15, and a control device for performing fuel injection control using the fuel injection device 13 (hereinafter referred to as "ECU: Electronic Control Unit"). 30), a hydraulic pump 17 driven by the driving force of the engine 11, a hydraulic device 20 having an actuator 19 operated by the hydraulic pressure supplied from the hydraulic pump 17, and a rotational speed for adjusting the engine rotational speed Ne And adjusting means 23. Typical examples of the industrial machine include a construction machine and an agricultural machine, but the field to which the present invention can be applied is not limited thereto.

  In the present embodiment, the engine 11 is a fuel injection type internal combustion engine represented by a diesel engine, for example, and the output (engine speed) changes according to the fuel injection amount Qf. The fuel injection device 13 is a device for injecting the fuel in the fuel tank 12 into the cylinder of the engine 11, and is a pressure accumulation type fuel injection device having a common rail (pressure accumulator) and an electromagnetically controlled fuel injection valve. Alternatively, a fuel injection device having a fuel injection nozzle that opens when the pressure of the supplied fuel exceeds a predetermined pressure is used, but the configuration is particularly limited as long as the fuel injection amount Qf can be adjusted. Not.

  The hydraulic pump 17 is a pump for supplying the hydraulic oil in the hydraulic oil tank 16 to the hydraulic device 20, and the drive shaft 18 is coupled to the engine 11, and the pump rotational speed according to the engine rotational speed Ne. Np is also changing. The hydraulic device 20 is provided with an actuator 19 for operating various operating mechanisms provided in the industrial machine, and a hydraulic control valve (not shown) for adjusting the operating hydraulic pressure supplied to the actuator 19. Yes.

  The ECU 30 is connected to a rotation speed adjustment means 23 such as a rotation speed adjustment dial or a speed lever so that the operation amount of the rotation speed adjustment means 23 can be detected by the ECU 30. Basically, the rotation speed adjusting means 23 adjusts the operation amount by the operator so that an appropriate amount of hydraulic oil corresponding to the work content is discharged from the hydraulic pump 17 toward the hydraulic device 20. ing. The ECU 30 sets the target rotational speed Ne_target according to the operation amount of the rotational speed adjusting means 23, and controls the fuel injection device 13 so that the engine rotational speed Ne_act detected by the rotational speed sensor 15 becomes the target rotational speed Ne_target. Is configured to do. Instead of the rotation speed adjustment means 23 for the operator to adjust the operation amount himself / herself, a rotation speed setting device capable of directly inputting an instruction value of the target rotation speed may be provided.

2. Configuration of Control Device (ECU) Next, an example of a specific configuration of the control device (ECU) 30 for the industrial machine engine according to the present embodiment will be described in detail.
FIG. 2 shows a part related to the control of the engine speed Ne in the configuration of the ECU 30 as a functional block. The ECU 30 is configured with a known microcomputer as the center, and includes a rotation speed detection means 31, a rotation speed control means 33, and a rotation speed reduction means 35 as main elements. Specifically, each of these means is realized by executing a program by a microcomputer. In addition, the ECU 30 includes storage means (not shown) such as a RAM (Random Access Memory).

  The rotation speed detection means 31 is configured to read the sensor signal Sne output from the rotation speed sensor 15 and obtain the engine rotation speed Ne_act and store it in the storage means.

  The rotational speed control means 33 sets the target rotational speed Ne_target of the engine 11 according to the operation amount of the rotational speed adjusting means 23, and controls the fuel injection device 13 so that the engine rotational speed Ne_act becomes the target rotational speed Ne_target. Is configured to run. Normally, when performing work using an industrial machine, the operation amount of the rotation speed adjusting means 23 is adjusted so that the engine rotation speed Ne_act becomes an appropriate rotation speed Ne0 according to the work.

  Further, during the work, the load applied to the hydraulic device 20 varies depending on the operating state of the operating mechanism of the industrial machine, and the load applied to the engine 11 varies. Therefore, the engine rotational speed Ne_act is maintained at the appropriate rotational speed Ne0. Therefore, it is necessary to adjust the fuel injection amount Qf according to the required load Tr for the engine 11. For example, when the load applied to the engine 11 increases, the required load Tr and the fuel injection amount Qf for the engine 11 required to maintain the engine speed Ne_act at the appropriate speed Ne0 increase. On the other hand, when the load applied to the engine 11 is reduced, the required load Tr and the fuel injection amount Qf for the engine 11 that are necessary for maintaining the engine speed Ne_act at the appropriate speed Ne0 are reduced.

  Specific control of the fuel injection device 13 for adjusting the fuel injection amount Qf is realized by a conventionally known method. Specifically, the rotational speed control means 33 obtains a required load Tr for the engine 11 by calculation based on a deviation ΔNe between the target rotational speed Ne_target and the actual engine rotational speed Ne_act, and target fuel injection corresponding to the required load Tr Each control unit of the fuel injection device 13 is controlled so that the quantity Qf_target is realized.

  For example, when the fuel injection device 13 is a pressure accumulation type fuel injection device, the rotation speed control means 33 adjusts the fuel pressure by performing energization control of a metering valve capable of adjusting the fuel flow rate, while controlling the fuel pressure. By performing energization control of the fuel injection valve, the fuel injection amount Qf is adjusted by adjusting the injection start timing and the injection time. When the fuel injection device 13 is a fuel injection device including the fuel injection nozzle as described above, the rotation speed control means 33 is an electronic governor provided in a high-pressure pump that supplies fuel to the fuel injection nozzle. By controlling this, the fuel injection amount Qf is adjusted by adjusting the injection start timing and the injection time.

  The rotation speed reduction means 35 reads a control parameter correlated with the load applied to the engine 11 and, when it is determined that the work using the industrial machine is not performed based on the value of this control parameter, the rotation speed adjustment means. The engine speed Ne_act is controlled to be reduced regardless of the operation amount of 23. Any control parameter can be used as long as it has a correlation with the load applied to the engine 11. In the ECU 30 of the present embodiment, the target fuel injection amount Qf_target in the control by the rotation speed control means 33 or the value of the required load Tr for the engine 11 is used as the control parameter, and it is accurately determined whether the work is being performed. It can be determined.

  Specifically, when the work using the industrial machine is not performed and the load applied to the hydraulic device 20 is close to zero, the engine 11 necessary for maintaining the engine speed Ne_act at the target speed Ne_target. The required load Tr and the target fuel injection amount Qf_target are small values. Therefore, the rotational speed reduction means 35 determines that the work using the industrial machine is not performed when the target fuel injection amount Qf_target or the required load Tr for the engine 11 is less than a predetermined reduction threshold Thre_down_on. The target rotational speed Ne_target in the rotational speed control means 33 is forcibly set to the low speed side target rotational speed Ne_target_low. At this time, a flag indicating that the low-speed control is being executed is set.

  The reduction threshold Thre_down_on for determining that the work is not performed is, for example, a minimum fuel injection amount Qf or a required load Tr value required for rotating the hydraulic pump 17 (in the following embodiments) The value of the reduction threshold Thre_down_on may be referred to as a “low load state value”). By using such a low load state value as the reduction threshold value Thre_down_on, it is possible to accurately determine a state in which work by the industrial machine is not performed.

  While the target rotational speed Ne_target is set to the low speed side target rotational speed Ne_target_low by the rotational speed reduction means 35, the rotational speed control means 33 causes the fuel injection device 13 so that the engine rotational speed Ne_act becomes the low speed side target rotational speed Ne_target_low. The fuel injection control by is executed. As a result, not only fuel consumption but also noise can be suppressed. The value of the low speed side target rotational speed Ne_target_low is set to a value corresponding to the idle rotational speed of the engine 11, for example. By setting the low speed side target rotation speed Ne_target_low to the idle rotation speed, fuel consumption and noise can be suppressed as small as possible in a range where the engine 11 is not misfired.

  Further, the rotational speed reduction means 35 reads the target fuel injection amount Qf_target or the required load Tr for the engine 11 while the target rotational speed Ne_target is set to the low-speed target rotational speed Ne_target_low, and the work using the industrial machine is performed. It is determined whether or not it has been resumed. Specifically, the rotation speed reduction means 35 determines that the work using the industrial machine has been resumed when the target fuel injection amount Qf_target or the required load Tr for the engine 11 becomes equal to or greater than a predetermined return threshold Thre_down_off. It is configured. When it is determined that the work has been resumed, the rotation speed reduction means 35 cancels the setting of the target rotation speed Ne_target set to the low speed side target rotation speed Ne_target_low. As a result, the target rotational speed Ne_target corresponding to the operation amount of the rotational speed adjusting means 23 is returned to the set state. At this time, the flag indicating the execution state of the low speed control is reset.

  The return threshold value Thre_down_off at this time is set to a value equal to or greater than the reduction threshold value Thre_down_on when the target rotational speed Ne_target is decreased, but the engine 11 is turned on / off for low speed control that forcibly decreases the target rotational speed Ne_target In order to prevent the control state of the engine speed Ne_act from being repeatedly switched due to load fluctuations, it is preferable that the return threshold Thre_down_off is larger than the decrease threshold Thre_down_on.

  Alternatively, when the target rotational speed Ne_target is forcibly decreased, the target rotational speed Ne_target is set when the target fuel injection amount Qf_target or the required load Tr for the engine 11 falls below the reduction threshold Thre_down_on for a predetermined time. By switching the above, it is possible to prevent the control state of the engine speed Ne_act from being switched unnecessarily. However, when the target rotational speed Ne_target is returned to a value corresponding to the operation amount of the rotational speed adjusting means 23, the target fuel injection amount Qf_target reaches the return threshold Thre_down_off so that the operation can be resumed quickly. At this point, it is preferable to switch the setting of the target rotational speed Ne_target.

  Further, it is preferable that the decrease threshold value Thre_down_on or the return threshold value Thre_down_off be a variable value according to the operating state of the engine 11 such as the engine temperature, the fuel temperature, and the engine speed. As a result, even when the fuel pumping efficiency of the high-pressure pump provided in the fuel injection device 13 varies due to the difference in the operating state of the engine 11, it is possible to accurately determine the interruption and resumption of work by the industrial machine. become. For example, the relationship between the engine temperature, the fuel temperature, the engine speed, etc., and the reduction threshold value Thre_down_on or the recovery threshold value Thre_down_off is mapped and stored in a ROM (Read Only Memory) of the ECU 30 so that the engine 11 is in operation. The engine temperature or the like can be detected, and a decrease threshold Thre_down_on or a return threshold Thre_down_off corresponding to the detected value can be used for determination.

  Further, in the case where the exhaust system of the engine 11 is provided with an exhaust purification device such as a particulate filter that collects particulate matter, control of regeneration of the particulate filter, etc. is performed by controlling the engine 11. It may be done. When the exhaust purification control is executed by the control of the engine 11, even if the work using the industrial machine is interrupted, the exhaust purification control is appropriately executed if the engine speed Ne is reduced. There is a risk of being lost.

  Since the engine 11 may be controlled for various purposes other than the operation of the operation mechanism of the industrial machine as well as the exhaust purification control, the rotational speed reducing means 35 is intended for the exhaust purification control. Preferably, the engine 11 is configured to determine whether or not the engine speed Ne may be decreased, such as whether or not the engine 11 is being controlled.

3. Here, the operation state of the engine 11 controlled by the ECU 30 of the present embodiment will be described with reference to FIG.
In FIG. 3, the vertical axis indicates the calculated value of the target fuel injection amount Qf_target (the required load Tr for the engine 11), and the horizontal axis indicates the engine speed Ne. Also, the hatched area in FIG. 3 represents a controllable area (operating area) during operation of the engine 11.

  When the target rotational speed Ne_target of the engine 11 is set to the appropriate rotational speed Ne0, if the load applied to the engine 11 increases due to an increase in the load on the hydraulic device 20, the engine rotational speed Ne_act decreases and the appropriate rotational speed is achieved. Below the number Ne0. Then, the target fuel injection amount Qf_target (required load Tr for the engine 11) increases (changes in the direction of arrow B) in accordance with the deviation ΔNe between the appropriate rotational speed Ne0 and the actual engine rotational speed Ne_act.

  On the other hand, when the target rotation speed Ne_target of the engine 11 is set to the appropriate rotation speed Ne0, when the load applied to the engine 11 is decreased, for example, the load applied to the hydraulic device 20 is decreased, the engine rotation speed Ne_act is increased. Exceeds proper rotation speed Ne0. Then, the target fuel injection amount Qf_target (the required load Tr for the engine 11) decreases according to the deviation ΔNe between the actual engine speed Ne_act and the appropriate engine speed Ne0 (changes in the direction of arrow A).

  Basically, the load applied to the hydraulic device 20 fluctuates from moment to moment while a predetermined work is being performed using an industrial machine. Therefore, the operating state of the engine 11 substantially follows the solid line X along with the load variation. Will change. On the other hand, when the work using the industrial machine is interrupted, the load applied to the hydraulic device 20 becomes extremely small, so the load applied to the engine 11 also decreases, and the target fuel injection amount Qf_target (the required load Tr for the engine 11) is It is less than the decrease threshold Thre_down_on.

  As a result, the stop of the work is recognized by the rotation speed reduction means 35 of the ECU 30, and the target rotation speed Ne_target is changed to the low speed side target rotation speed Ne_target_low regardless of the operation amount of the rotation speed adjustment means 23, thereby controlling the engine rotation speed Ne. Is done. While the work using the industrial machine is interrupted, the load on the engine 11 does not basically fluctuate greatly, so the engine speed Ne_act and the target fuel injection amount Qf_target (required load Tr for the engine 11). Becomes a stable state, and the operation of the engine 11 at low speed is continued.

  Further, when the operation is resumed while the target rotational speed Ne_target is set to the low-speed side target rotational speed Ne_target_low and the engine rotational speed Ne is being controlled, the load on the hydraulic device 20 increases and the engine 11 Such a load also increases. As a result, when the target fuel injection amount Qf_target (required load Tr for the engine 11) increases and reaches the return threshold Thre_down_off, the resumption of work is recognized by the rotation speed reduction means 35 of the ECU 30, and the current target rotation speed Ne_target Is released, and the control of the engine speed Ne at the appropriate speed Ne0 corresponding to the operation amount of the speed adjusting means 23 is resumed.

4). Next, an example of a method for controlling the engine speed Ne executed by the ECU 30 according to the present embodiment will be described with reference to the flowcharts of FIGS.

  First, in step S1 after the start, the ECU 30 determines whether or not a flag indicating an execution state of the low speed control is reset. If the flag is reset and the low speed control is not being executed, it is determined Yes in step S1 and the process proceeds to step S2.

  In step S <b> 2 that has proceeded without the low speed control being executed, the ECU 30 calculates and sets the target rotational speed Ne_target based on the operation amount of the rotational speed adjusting means 23. Next, in step S3, the ECU 30 calculates a target fuel injection amount Qf_target.

  FIG. 5 is a flowchart showing a procedure for calculating the target fuel injection amount Qf_target. In calculating the target fuel injection amount Qf_target, the ECU 30 first detects the current engine rotational speed Ne_act based on the sensor signal Sne of the rotational speed sensor 15 in step S21, and then sets the set target rotational speed in step S22. The engine speed deviation ΔNe is calculated by subtracting the detected engine speed Ne_act from the number Ne_target. In step S23, the ECU 30 calculates the target fuel injection amount Qf_target by map calculation or the like based on the deviation ΔNe.

  Returning to FIG. 4, when the target fuel injection amount Qf_target is calculated in step S3, then in step S4, the ECU 30 determines whether or not the target fuel injection amount Qf_target is less than the reduction threshold Thre_down_on. As the reduction threshold Thre_down_on, a predetermined value set in advance or a value obtained by map calculation according to the operating state of the engine 11 such as the engine temperature is used. If the target fuel injection amount Qf_target is greater than or equal to the reduction threshold Thre_down_on, it is determined No in step S4, and the ECU 30 proceeds to step S12 after resetting the timer T1 in step S5, and the target fuel injection calculated in step S3. Fuel injection control is executed based on the quantity Qf_target, and the process returns to the start.

  FIG. 6 is a flowchart showing a procedure for performing the fuel injection control. When performing the fuel injection control, the ECU 30 calculates the control value of each control unit of the fuel injection device 13 based on the target fuel injection amount Qf_target in step S31, and then operates the control unit in step S32. Outputs a control instruction signal. As a result, fuel is injected from the fuel injection device 13 into the cylinder of the engine 11.

  Returning to FIG. 4, if the target fuel injection amount Qf_target is less than the reduction threshold Thre_down_on in step S <b> 4 described above, it is determined Yes and the process proceeds to step S <b> 6. In step S6, the ECU 30 counts up the timer T1, and then in step S7, the ECU 30 determines whether or not the timer T1 has reached the threshold value Ta. If the timer T1 has not reached the threshold value Ta, the determination is No and the process proceeds to step S12. The ECU 30 executes fuel injection control based on the target fuel injection amount Qf_target calculated in step S3, and returns to the start.

  On the other hand, if the timer T1 has reached the threshold Ta in step S7, it is determined Yes and the process proceeds to step S8. The ECU 30 sets a flag indicating the execution state of the low speed control in step S8, resets the timer T1 in step S9, and then sets the target rotational speed Ne_Target of the engine 11 to the low speed side target rotational speed Ne_target_low in step S10. Set. Next, in step S11, the ECU 30 calculates the target fuel injection amount Qf_target according to the flowchart of FIG. 5, and then in step S12, based on the target fuel injection amount Qf_target calculated in step S11, according to the flowchart of FIG. After executing the fuel injection control, the process returns to the start.

  In step S1 after the start, the flag indicating the execution state of the low speed control is set. If the low speed control is being executed, the determination is No and the process proceeds to step S13. After setting the target rotational speed Ne_target to the low speed side target rotational speed Ne_target_low in step S13, the ECU 30 calculates the target fuel injection amount Qf_target in step S14 according to the flowchart of FIG.

  Next, in step S15, the ECU 30 determines whether or not the target fuel injection amount Qf_target calculated in step S14 is greater than or equal to the return threshold value Thre_down_off. If the target fuel injection amount Qf_target is less than the return threshold Thre_down_off, it is determined No and the process proceeds to step S12 as it is, and the ECU 30 follows the flowchart of step S6 based on the target fuel injection amount Qf_target calculated in step S14. After executing the fuel injection control, the process returns to the start.

  On the other hand, if the target fuel injection amount Qf_target is greater than or equal to the return threshold Thre_down_off in step S15, it is determined Yes and the process proceeds to step S16, where the ECU 30 resets a flag indicating the execution state of the low speed control. Next, the ECU 30 calculates and sets the target rotational speed Ne_target based on the operation amount of the rotational speed adjusting means 23 in step S17, and calculates the target fuel injection amount Qf_target in step S18 according to the flowchart of FIG. Then, it progresses to step S12. In step S12, the ECU 30 executes fuel injection control according to the flowchart of FIG. 6 based on the target injection amount Qf_target calculated in step S18, and then returns to the start.

  In order to determine whether or not the engine speed Ne can be decreased at present, such as whether the control of the engine 11 for exhaust purification control is not being executed, for example, step S3 or step After S7, a step for performing such a determination is provided.

  According to the ECU 30 of the present embodiment and the engine speed control method executed by the ECU 30, it is determined whether or not an operation using an industrial machine is being performed by determining whether the target fuel injection amount Qf_target or the required load on the engine 11 is satisfied. This is performed based on control parameters such as Tr. Therefore, it is not necessary to provide an additional switch, sensor, or the like in the industrial machine in order to execute the auto-decel function, and an increase in cost can be suppressed. Further, since it is not necessary to perform an operation by the operator when determining whether or not an operation using an industrial machine is being performed, the burden on the operator can be reduced.

Further, according to the ECU 30 and the engine speed control method executed by the ECU 30 according to the present embodiment, the engine speed Ne is automatically suppressed while the operation is interrupted. It can be improved further.
Furthermore, the ECU 30 and the engine speed control method executed by the ECU 30 of the present embodiment detect that the operation is interrupted by the arithmetic processing of the ECU 30 of the fuel injection system and reduce the engine speed Ne. Therefore, even in an existing industrial machine that does not have an auto-decel function, the auto-decel function can be easily executed by replacing the ECU 30.

[Second Embodiment]
1. Control unit (ECU)
FIG. 7 is a functional block diagram showing a part related to the control of the engine speed Ne in the configuration of the control device (ECU) 40 according to the second embodiment of the present invention. The ECU 40 of the present embodiment is set with a plurality of target rotational speeds Ne_target for reducing the engine rotational speed Ne.

  The basic configuration of the ECU 40 of the present embodiment is configured around a known microcomputer as in the ECU 30 of the first embodiment, and includes a rotation speed detection means 31, a rotation speed control means 33, The rotational speed reducing means 45 is provided as a main element. Among these, the rotation speed detection means 31 and the rotation speed control means 33 have the same configurations as the respective means of the ECU 30 of the first embodiment.

  On the other hand, the rotation speed reduction means 45 in the ECU 40 of the present embodiment uses a low load as a reduction threshold to be compared with the target fuel injection amount Qf_target (required load Tr for the engine 11) as a control parameter correlated with the load on the engine 11. A state value Thre_down_onA and a medium load state value Thre_down_onB are provided. When the target fuel injection amount Qf_target is lower than the low load state value Thre_down_onA, the rotation speed reduction means 45 performs the same control (low speed control) as the rotation speed reduction means 35 of the ECU 30 of the first embodiment. It is comprised so that.

  Further, the rotational speed reducing means 45 of the ECU 40 according to the present embodiment has the target fuel injection amount Qf_target even when the target fuel injection amount Qf_target is not less than the low load state value Thre_down_onA and it can be determined that the operation is not interrupted. Is lower than the medium load state value Thre_down_onB, it is determined that the load of the hydraulic device 20 required for the work is medium and sufficient, and the target rotational speed Ne_target is determined regardless of the operation amount of the rotational speed adjusting means 23. Is set to the medium speed side target rotational speed Ne_target_mid (medium speed control).

  For a specific method for setting the target rotational speed Ne_target to the medium speed target rotational speed Ne_target_mid and a specific method for returning the target rotational speed Ne_target to a value corresponding to the operation amount of the rotational speed adjusting means 23, refer to the case of low speed control. It can be configured in the same manner.

2. FIG. 8 is a diagram showing the operating state of the engine 11 controlled by the ECU 40 of the present embodiment. The vertical axis shows the calculated value of the target fuel injection amount Qf_target (the required load Tr for the engine 11). The horizontal axis indicates the engine speed Ne. Further, the hatched area in FIG. 8 represents the operating area of the engine 11.

  While the target rotational speed Ne_target of the engine 11 is set to the appropriate rotational speed Ne0 and the work using the industrial machine is being performed, the operation state of the engine 11 is approximately the solid line X due to the load variation applied to the hydraulic device 20. Varies along. At this time, depending on the working state, the load on the hydraulic device 20 is kept slightly small, the load on the engine 11 is also moderate, and the target fuel injection amount Qf_target may be lower than the medium load state value Thre_down_onB. Then, a moderate workload state is recognized by the rotation speed reduction means 45 of the ECU 40, and the target rotation speed Ne_target is changed to the medium speed side target rotation speed Ne_target_mid regardless of the operation amount of the rotation speed adjustment means 23, and the engine rotation speed is changed. Ne will be controlled.

  Further, when the load on the hydraulic device 20 increases while the target rotation speed Ne_target is set to the medium speed target rotation speed Ne_target_mid and the engine rotation speed Ne is being controlled, the load on the engine 11 also increases again. To do. As a result, when the target fuel injection amount Qf_target increases and reaches the return threshold value Thre_down_offB, the target rotational speed Ne_target set to the medium speed target rotational speed Ne_target_mid is canceled, and the operation amount of the rotational speed adjusting means 23 is increased. The control of the engine rotational speed Ne at the appropriate rotational speed Ne0 is resumed.

  In addition, when the control of the engine speed Ne at the appropriate speed Ne0 or the medium speed control is being executed, the operation is interrupted and the target fuel injection amount Qf_target falls below the low load state value Thre_down_onA. Regardless of the operation amount of the rotational speed adjusting means 23, the target rotational speed Ne_target is changed to the low speed side target rotational speed Ne_target_low, and the engine rotational speed Ne is controlled.

  Further, the target fuel injection amount Qf_target (required load Tr for the engine 11) is obtained as a result of the operation being resumed while the target rotational speed Ne_target is set to the low-speed target rotational speed Ne_target_low and the engine rotational speed Ne is being controlled. Increases to reach the return threshold value Thre_down_offA, the target rotational speed Ne_target set in the low-speed target rotational speed Ne_target_low is canceled, and the engine at the appropriate rotational speed Ne0 corresponding to the operation amount of the rotational speed adjusting means 23 is released. Control of the rotational speed Ne is resumed.

3. Next, an example of a method for controlling the engine speed Ne executed by the ECU 40 of the present embodiment will be described with reference to the flowcharts of FIGS.

  First, in step S41 after the start, the ECU 40 determines whether or not a flag indicating an execution state of the low speed control has been reset. If the flag is set and the low speed control is being executed, No is determined in step S41, and the process proceeds to step S13. Thereafter, the ECU 40 executes arithmetic processing in accordance with the procedure of steps S13 to S18 in the flowchart of FIG. The return threshold Thre_down_on in step S15 at this time is read as Thre_down_onA. Thereafter, the process proceeds to step S52 where the ECU 40 executes fuel injection control according to the flowchart of FIG. 6 and returns to the start.

  On the other hand, if the flag is reset in step S41 and the low speed control is not executed, the determination in step S1 is Yes and the process proceeds to step S42. Next, in step S42, the ECU 40 determines whether or not the flag indicating the execution state of the medium speed control has been reset. If the flag is set and the medium speed control is being executed, it is determined No in step S42, and the arithmetic processing is executed according to the flowchart of FIG.

  Steps S71 to S76 in the flowchart of FIG. 10 are the low-speed target rotational speed Ne_target_low, the return threshold Thre_down_offA, and the low-speed control in steps S13 to S18 in the flowchart of FIG. 4 are the medium-speed target rotational speed Ne_target_mid and return, respectively. The threshold Thre_down_offB is replaced with medium speed control, and the same arithmetic processing as in steps S13 to S18 is executed.

  In step S52, which has been performed after the calculation processing of steps S71 to S76, the ECU 40 performs fuel injection according to the flowchart of FIG. 6 based on the target fuel injection amount Qf_target calculated in step S72 or step S76. Execute control and return to start. In step S73, when the target fuel injection amount Qf_target is less than the return threshold value Thre_down_offB, the medium speed control is continued. When the target fuel injection amount Qf_target is greater than or equal to the return threshold value Thre_down_offB, the operation amount of the rotation speed adjusting means 23 is set. Return to the corresponding control.

  Returning to FIG. 9, in step S <b> 43 in which neither the low speed control nor the medium speed control is executed, the ECU 40 calculates and sets the target rotational speed Ne_target based on the operation amount of the rotational speed adjusting means 23. Next, in step S44, the ECU 40 calculates a target fuel injection amount Qf_target according to the flowchart of FIG.

  When the target fuel injection amount Qf_target is calculated in step S44, then in step S45, the ECU 40 determines whether or not the target fuel injection amount Qf_target is less than the low load state value Thre_down_onA. If the target fuel injection amount Qf_target is less than the low load state value Thre_down_onA, “Yes” is determined in step S45, and the process proceeds to step S46. After step S46, each calculation process of step S46 to step S51 is executed according to the same procedure as step S6 to step S11 in FIG.

  In step S52, which has been executed after the calculation processing of step S46 to step S51, the ECU 40 performs fuel injection according to the flowchart of FIG. 6 based on the target fuel injection amount Qf_target calculated in step S44 or step S51. Execute control and return to start. In step S47, when the timer T1 has reached the threshold value Ta, the control is switched to the low speed control. When the timer T1 has not reached the threshold value Ta, the control according to the operation amount of the rotation speed adjusting means 23 is continued. Be made.

  On the other hand, if the target fuel injection amount Qf_target is equal to or greater than the low load state value Thre_down_onA in step S45, the determination is No and the process proceeds to step S53. The ECU 40 resets the timer T1, and then proceeds to step S54. Next, in step S54, the ECU 40 determines whether or not the target fuel injection amount Qf_target calculated in step S44 is less than the medium load state value Thre_down_onB.

  If the target fuel injection amount Qf_target is equal to or greater than the medium load state value Thre_down_onB, it is determined No in step S54, and after resetting the timer T2 in step S61, the ECU 40 proceeds to step S52 and calculates in step S44. Based on the target fuel injection amount Qf_target, the fuel injection control is executed according to the flowchart of FIG. On the other hand, if the target fuel injection amount Qf_target is less than the medium load state value Thre_down_onB, “Yes” is determined in step S54, and the process proceeds to step S55.

  Step S55 to step S60 after step S55 are the timer T1, the threshold Ta, the low speed control, the low speed side target rotation speed Ne_target_low of the step S6 to the step S11 in the flowchart of FIG. The medium speed side target rotation speed Ne_target_mid is replaced, and the same arithmetic processing as in steps S6 to S11 is executed.

  In step S52, which has been performed after the calculation processing of step S55 to step S60, the ECU 40 performs fuel injection according to the flowchart of FIG. 6 based on the target fuel injection amount Qf_target calculated in step S44 or step S60. Execute control and return to start. In step S56, when the timer T2 has reached the threshold value Tb, the control is switched to the medium speed control, and when the timer T2 has not reached the threshold value Tb, control according to the operation amount of the rotation speed adjusting means 23 is performed. Be continued.

  In order to determine whether or not the engine speed Ne can be decreased at present, such as whether the control of the engine 11 for the purpose of exhaust purification control is not executed, for example, step S44 or step After S47 and step S56, a step for performing such determination is provided.

  According to the ECU 40 of the present embodiment and the engine speed control method executed by the ECU 40, basically the same effects as the ECU 30 and the engine speed control method of the first embodiment can be obtained. . Furthermore, according to the ECU 40 and the engine speed control method of the present embodiment, the medium speed control and the low speed control can be executed according to the load applied to the hydraulic device 20 regardless of the operation amount of the speed adjusting means 23. Therefore, fuel consumption and useless noise can be further reduced.

[Third Embodiment]
FIG. 11 is a functional block diagram showing a part related to the control of the engine speed Ne in the configuration of the control device (ECU) 50 according to the third embodiment of the present invention. The ECU 50 of the present embodiment is configured so as to determine the current working state based on the value of the control parameter correlated with the load applied to the engine 11 and reduce the engine speed Ne. It is comprised similarly to ECU30 and 40 of 2nd Embodiment. Furthermore, when the engine 11 is excessively loaded, the ECU 50 according to the present embodiment increases the target rotational speed Ne_target regardless of the operation amount of the rotational speed adjusting means 23, and the engine 11 stops. Can be prevented.

  The basic configuration of the ECU 50 according to the present embodiment is configured around a known microcomputer in the same manner as the ECUs 30 and 40 according to the first and second embodiments. The ECU 50 includes a rotation speed detection means 31, a rotation speed control means 33, a rotation speed reduction means 35 (45), and a rotation speed increase means 57 as main elements. Among these, the rotation speed detection means 31, the rotation speed control means 33, and the rotation speed reduction means 35 (45) have the same configurations as the respective means of the ECUs 30 and 40 of the first or second embodiment.

  The rotational speed increasing means 57 reads a control parameter correlated with the load applied to the engine 11 such as the target fuel injection amount Qf_target (required load Tr for the engine 11) and determines that the engine 11 is excessively loaded. Is configured to perform control to increase the engine rotational speed Ne_act regardless of the operation amount of the rotational speed adjusting means 23. Specifically, the rotational speed increasing means 57 forcibly sets the target rotational speed Ne_target in the rotational speed control means 33 to the high speed side target rotational speed Ne_target_high when the target fuel injection amount Qf_target is equal to or greater than a predetermined upper limit threshold Thre_up_on. Set.

  When the target rotational speed Ne_target is set to the high speed side target rotational speed Ne_target_high by the rotational speed increasing means 57, the rotational speed control means 33 is controlled by the fuel injection device 13 so that the engine rotational speed Ne_act becomes the high speed side target rotational speed Ne_target_high. Fuel injection control is executed. As a result, the fuel injection amount Qf is increased, the output of the engine 11 is increased, and the engine 11 is prevented from stopping.

  Further, the rotational speed increasing means 57 reads the target fuel injection amount Qf_target even while the target rotational speed Ne_target is set to the high speed side target rotational speed Ne_target_high, and determines that the load on the engine 11 has returned to a normal level or less. In this case, the target rotational speed Ne_target is set so as to be set according to the operation amount of the rotational speed adjusting means 23. Therefore, fuel consumption and noise are not increased more than necessary.

  According to the ECU 50 of the present embodiment and the engine speed control method executed by the ECU 50, basically the same effects as the ECUs 30 and 40 and the engine speed control method of the first or second embodiment. Can be obtained. Furthermore, the ECU 50 and the engine speed control method of the present embodiment determine a state in which the engine 11 is overloaded without using an additional sensor or the like, and in such a state, adjust the speed. Regardless of the operation amount of the means 23, the target rotation speed Ne_target is increased to increase the output of the engine 11. Therefore, it is possible to prevent the engine 11 from being stopped due to excessive load on the engine 11.

Claims (10)

In a control device for an industrial machine engine that controls an engine that drives a hydraulic pump for supplying the hydraulic pressure to a hydraulic device operated by hydraulic pressure,
A rotational speed control means for controlling the engine so that the engine rotational speed becomes the target rotational speed based on an instruction of the target rotational speed;
When a control parameter correlated with a load applied to the engine is read to determine whether the value of the control parameter is less than a predetermined decrease threshold, and when the value of the control parameter is less than the decrease threshold A speed reduction means for reducing the engine speed regardless of the instruction of the target speed,
An industrial machine engine control apparatus comprising:   2. The industrial machine according to claim 1, wherein the engine speed reduction means reduces the engine speed when a predetermined time elapses in a state where the value of the control parameter is less than the threshold for reduction. Engine control device.   The industrial machine engine control device according to claim 1, wherein the control parameter is a fuel injection amount or a required load on the engine.   The rotational speed reduction means determines whether or not the value of the control parameter is equal to or greater than a predetermined return threshold after reducing the engine speed, and the value of the control parameter is equal to or greater than the return threshold. The control device for an industrial machine engine according to any one of claims 1 to 3, wherein the control for decreasing the engine speed is released when the engine speed is reached.   The industrial machine engine control device according to claim 4, wherein the return threshold value is larger than the decrease threshold value.   6. The reduction threshold value is a low load state value corresponding to a minimum value of the control parameter required for rotating the hydraulic pump. Control device for industrial machinery engine.   The engine speed is decreased when a medium load state value greater than the low load state value is further set as the reduction threshold and the control parameter value becomes less than the medium load state value. The set value of is set to a value larger than the set value of the engine speed to be decreased when the value of the control parameter becomes less than the low load state value. The industrial engine control device according to one item.   The industrial engine control device according to any one of claims 1 to 7, wherein the reduction threshold value or the return threshold value is a variable value corresponding to an operating state of the engine. The rotational speed of an engine for an industrial machine that controls the engine so that the rotational speed of an engine that drives a hydraulic pump for supplying the hydraulic pressure to a hydraulic device that is operated by hydraulic pressure becomes an instructed target rotational speed. In the control method,
When a control parameter correlated with a load applied to the engine is read to determine whether the value of the control parameter is less than a predetermined decrease threshold, and when the value of the control parameter is less than the decrease threshold Reducing the engine speed regardless of the target speed instruction;
An engine speed control method for an industrial machine characterized by comprising:   After reducing the engine speed, it is determined whether or not the value of the control parameter is equal to or greater than a predetermined return threshold, and when the value of the control parameter is equal to or greater than the return threshold, the engine 10. The method for controlling the rotational speed of an engine for an industrial machine according to claim 9, wherein control for reducing the rotational speed of the engine is canceled.

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