JP4977722B2 - Engine speed control device for work machines - Google Patents

Description

  The present invention relates to an engine speed control device for a work machine that is provided in a work machine such as a hydraulic excavator and controls the engine speed.

  2. Description of the Related Art Conventionally, a work machine such as a hydraulic excavator is provided with an engine speed control device for the work machine in order to control the speed of a mounted engine. This type of engine speed control device includes an engine controller (engine speed calculation unit) that calculates a target engine speed, a work mode storage unit that stores a speed corresponding to each of a plurality of work modes, A work mode switching switch (work mode switching means) that selects any one of the work modes and a work mode control unit that outputs the selected work mode to the engine controller are provided.

  In addition, the work mode includes an economy mode that is a mode during light load work and a high load mode that is higher in rotation speed than the economy mode. For example, the work content is work such as light excavation. The economy mode is used, and the high load mode is used in the case of normal excavation, rooting or deep excavation or other heavy excavation work.

  When an operator operating this type of work machine selects an economy mode or a high load mode as a work mode with a work mode changeover switch, the work mode control unit outputs the selected work mode to the engine controller. The engine controller that has received this output reads the engine speed corresponding to the work mode output from the work mode control unit from the work mode storage unit, and outputs the read engine speed as the target engine speed. Control the engine speed.

  Thus, the operator can freely select a work mode suitable for the work content with the work mode changeover switch, thereby controlling the engine speed and saving extra fuel consumption. However, if it is left to the operator to select the work mode at the actual work site, even if the work content is light load work, the operator can freely change the work mode to a high load mode with higher workability than the economy mode. There is a risk of using.

  Therefore, in order to restrict the change of the work mode repeated during the work of the work machine, the engine speed control of the work machine provided with the change management means for restricting or permitting the change of the work mode selected by the work mode changeover switch. An apparatus has been proposed (see, for example, Patent Document 1).

JP 2006-226255 A

  By the way, in the engine speed control device for a work machine disclosed in Patent Document 1, once the change of the work mode is restricted, the work mode used last time when the work machine is used is continued. Therefore, when the work is finished while the previous work mode is limited to the high load mode and the current work content is a light load work, the engine controls the engine speed in the high load mode at the start of the work machine. Therefore, there was a problem that extra fuel was consumed and the economy was low. In addition, when the work is finished while the previous work mode is restricted in the economy mode and the current work content is a high load work, the work machine administrator etc. It is necessary to set the change management means so that the change is approved and the change management means does not restrict the change of the work mode. Therefore, there is a possibility that the work mode cannot be changed when the manager of the work machine is absent, and there is a problem that the setting of the change management means becomes complicated and the convenience is low.

  The present invention has been made in view of such a state of the art, and an object of the present invention is an engine of a working machine that can suppress the consumption of excess fuel and can easily change the working mode. An object of the present invention is to provide a rotation speed control device.

In order to achieve the above object, an engine speed control device for a work machine according to the present invention is provided in a work machine having an engine, and an engine speed calculation unit that calculates a target speed of the engine; A work mode storage unit for storing a rotation speed corresponding to each of a plurality of work modes including an economy mode that is a time mode and a high load mode having a higher rotation speed than the rotation speed of the economy mode, and the plurality of operations A work mode switching means for selecting any one of the modes; and a work mode control section for outputting the work mode selected by the work mode switching means to the engine speed calculation section. The engine reads out the engine speed corresponding to the work mode output from the work mode control unit from the work mode storage unit, In the engine rotation speed control device for a work machine that outputs the engine rotation speed as the target rotation speed, the work mode control unit is configured to switch the work mode switching means at the time of start of the work machine. look including the startup process means be selected performs starting processing for outputting the economy mode to the engine rotational speed computing unit, connected to the work mode control unit, the starting process by the startup processing means An external maintenance device that outputs a signal for enabling or disabling the operation mode, and the work mode control unit stops the work machine from a state where the work in the high load mode is being performed, and for a certain period of time after the stop. When the work machine is started before the time elapses, the start time processing by the start time processing means is invalidated and the work mode is The high load mode comprises disabling processing means for performing processing to output to the engine rotational speed computing section as the external maintenance apparatus is characterized in that it comprises a variably settable setting means the predetermined time.

In the present invention configured as described above, when the previous work mode is the high load mode and the work is finished, and the current work content is a light load work, the economy mode automatically suits the work content. No fuel is consumed. In addition, when the work is finished while the previous work mode is limited to economy mode and the current work content is high-load work, the work mode selector switch is kept in economy mode after starting the work machine Thus, the work mode can be easily changed from the high load mode to the high load mode, so that it is not necessary to obtain permission for changing the work mode from a manager of the work machine or the like and to make complicated settings. In addition, when the operator knows that the work content starts in high-load work in advance, the high-load mode is used from the start of the work machine by outputting a signal to be invalidated by the external maintenance device. Therefore, convenience can be improved. Furthermore, even if the operator interrupts the work once during the work in the high load mode, if the work machine is started within a certain time, the work can be performed again in the high load mode, so that continuity of the work can be ensured. In addition, a fixed time suitable for work can be easily set by the external maintenance device.

  In the engine rotation speed control device for a work machine according to the present invention, in the above invention, the work machine includes a monitor display device capable of displaying a current work mode, and the work mode control unit operates when the work machine is started. Including display processing means for performing processing for displaying on the monitor display device that the engine speed is controlled by the speed of the economy mode when a work mode other than the economy mode is selected by the mode switching means. It is a feature.

  In the present invention configured as described above, even if the operator selects a work mode other than the economy mode by the work mode switching means, the current work mode can be known by the monitor display device. Or, it is possible to prevent concern about failure of the work machine.

  In the engine speed control device for a work machine according to the present invention, in the invention, the work machine includes a hydraulic pump driven by the engine, and a hydraulic actuator operated by pressure oil discharged from the hydraulic pump. A discharge pressure that detects a discharge pressure of the hydraulic pump, and includes a direction control valve that controls a flow of pressure oil supplied from the hydraulic pump to the hydraulic actuator, and an operation device that switches the direction control valve. It is determined which of the above-described work modes corresponds to the detection means and the work content actually performed by the discharge pressure detection means, and the determined work mode is output to the work mode control unit. A work load calculation unit, and the work mode control unit is configured to perform the start-up processing means when the high load mode is output from the work load calculation unit. Stopping the starting process is characterized in that it comprises a stop processing unit that performs a stop process of outputting the high-load mode to the engine rotational speed computing section. With this configuration, the operation mode is automatically changed to the work mode suitable for the work load by the stop process by the stop processing unit regardless of the work mode selected by the work mode changeover switch, and the operability can be improved. , Can reduce fuel consumption.

  In the engine speed control device for a work machine according to the present invention, the work mode control unit outputs the economy mode to the engine speed calculation unit regardless of which work mode is selected by the work mode switching means when the work machine is started. It is suitable for work content automatically when the previous work mode is high load mode and the current work content is light load work. Because it becomes economy mode, it does not consume extra fuel. Thereby, economical efficiency can be improved compared with the past. In addition, when the work is completed while the previous work mode is limited to the economy mode and the current work content is a high-load work, the work mode selector switch can easily switch from the economy mode to the high-load mode after starting the work machine. Therefore, it is not necessary to obtain permission for changing the work mode from a manager of the work machine or the like, and it is not necessary to make complicated settings. Thereby, convenience can be improved compared with the past.

1 is a side view showing a hydraulic excavator cited as an example of a work machine provided with an embodiment of an engine speed control device for a work machine according to the present invention. It is a figure which shows the structure of the engine speed control apparatus which concerns on this embodiment with which the hydraulic shovel shown in FIG. 1 is equipped. It is a flowchart which shows the process sequence in the work mode control part with which this embodiment is equipped.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the engine speed control apparatus of the working machine which concerns on this invention is demonstrated based on figures.

  FIG. 1 is a side view showing a hydraulic excavator cited as an example of a working machine provided with an embodiment of an engine rotation speed control device for a working machine according to the present invention, and FIG. 2 shows the embodiment provided in the hydraulic excavator shown in FIG. It is a figure which shows the structure of the engine speed control apparatus which concerns on a form.

  An engine rotation speed control device for a work machine according to an embodiment of the present invention is applied to a work machine, for example, a hydraulic excavator 1. As shown in FIG. 1, the hydraulic excavator 1 is arranged on a traveling body 2, a revolving body 3 that is disposed on the upper side of the traveling body 2 and has a revolving frame 3 a, and is attached to the revolving body 3 to rotate in the vertical direction. It is comprised from the front work machine 4 which moves. The revolving unit 3 includes a cab 7 at the front, a counterweight 6 at the rear, and an engine room 5 between the cab 7 and the counterweight 6.

  As shown in FIG. 2, the engine speed control device for a work machine according to this embodiment includes an engine speed calculation unit 10 that calculates a target speed of an engine (not shown) provided in the engine room 5, and a plurality of A work mode storage unit 11 that stores the number of rotations according to each of the work modes, for example, three work modes, and a work mode switching means for selecting any one of these three work modes, for example, a work mode switch 12 A work mode control unit 13 for outputting the selected work mode to the engine speed calculation unit 10; and a monitor display provided in the cab 7 so that the work mode currently being operated can be visually recognized by the output from the work mode control unit 13 Device 16.

  The above work modes include an economy mode, which is a mode for light load work such as light excavation work and leveling work, and a high load mode with a higher rotation speed than this economy mode. There are a normal mode used for this work and a heavy excavation mode which is higher in rotation speed than this normal mode and used for heavy excavation work such as rooting and deep excavation. The engine speed calculation unit 10 is connected to an engine speed adjustment dial 14 that can adjust the engine speed in each of these three work modes.

  On the other hand, as shown in FIG. 2, the hydraulic excavator 1 includes a hydraulic pump 20 driven by an engine, a boom cylinder, an arm cylinder, a bucket cylinder, a swing motor that is operated by pressure oil discharged from the hydraulic pump 20, A hydraulic actuator (not shown) such as a travel motor, a direction control valve 21 for controlling the flow of pressure oil supplied from the hydraulic pump 20 to the hydraulic actuator, and an operating device 22 for switching the direction control valve 21 are provided. . A discharge pressure detection unit 18 that detects the discharge pressure of the hydraulic pump 20 and an operation amount detection unit 19 that detects an operation amount of the operation device 22 are provided. The operation amount detection means 19 is a pilot secondary pressure that is generated by reducing the pilot primary pressure from the pilot pump 25 in accordance with the operation of the operating device 22 by the pressure reducing valve 22 a and is guided as a pressure for switching the direction control valve 21. Is detected. That is, the value of the pilot secondary pressure corresponding to the operation amount of the operation device 22 detected by the operation amount detection means 19, that is, the operation amount is output to the work load calculation unit 17 described later.

  Further, the engine speed control device for the work machine according to the present embodiment is based on the discharge pressure of the hydraulic pump 20 detected by the discharge pressure detection means 18 and the operation amount detected by the operation amount detection means 19. It is provided with a workload calculation unit 17 that determines which of the above-described work modes the work content actually performed corresponds to, and outputs the determined work mode to the work mode control unit 13. . The work load calculation unit 17 determines that the operation is a high load operation when the operation amount of the operating device 22 is larger than a predetermined amount and the discharge pressure of the hydraulic pump 20 detected by the discharge pressure detecting means 18 is larger than the predetermined pressure.

  Here, the work mode control unit 13 includes four processing units, that is, a startup processing unit 13a, a display processing unit 13b, an invalid processing unit 13c, and a stop processing unit 13d. Hereinafter, these four processing means will be described in order.

  When the hydraulic excavator 1 is turned on and started, the start time processing means 13a operates the economy mode in the economy mode regardless of which of the three modes is selected by the operation mode changeover switch 12 at this time. Is a processing means for performing start-up processing for outputting the engine speed to the engine speed calculation unit 10.

  When the start time processing by the start time processing means 13a is effective, the display processing means 13b turns on the hydraulic excavator 1 and starts it up. At this time, the work mode changeover switch 12 causes the normal mode or heavy load other than the economy mode. Even when the excavation mode is selected, the processing unit 13 performs processing for displaying on the monitor display device 16 that the engine speed is controlled by the speed of the economy mode that is actually implemented. is there.

  The invalidation processing means 13c stops the hydraulic excavator 1 by turning off the power from the state where the engine speed of the hydraulic excavator 1 is operating in the high load mode normal mode or the heavy excavation mode. When the hydraulic excavator 1 is started again by turning on the power before a predetermined time A has elapsed from when the hydraulic excavator 1 is stopped, the work mode control unit 13 is started by the start time processing means 13a. This is a processing means for performing processing for invalidating the time processing and outputting the normal mode or the heavy excavation mode of the high load mode as the work mode to the engine speed calculation unit 10.

  When the start time processing by the start time processing means 13a is valid, the stop processing means 13d is configured so that when the high load mode normal mode or heavy excavation mode is output from the work load calculation section 17, the work mode control section 13 This is a processing means for performing a stop process for stopping the start-time process by the start-time processing means 13a and outputting the normal mode or the heavy excavation mode in the high load mode to the engine speed calculator 10.

  The work mode control unit 13 is appropriately connected with an external maintenance device 15 that outputs a signal for validating or invalidating the start-up process by the start-up processing means 13a. The external maintenance device 15 includes setting means capable of variably setting the above-described predetermined time A for disabling the economy mode at the time of engine start.

  The operation of the engine speed control device for a work machine according to this embodiment configured as described above will be described below.

  FIG. 3 is a flowchart showing a processing procedure in the work mode control unit provided in the present embodiment.

  As shown in FIG. 3, when the hydraulic excavator 1 is started by turning on the power, the work mode control unit 13 determines whether or not the start time processing by the start time processing means 13a is valid or invalid (S1). If the start time processing by the start time processing means 13a is valid, the work mode control unit 13 outputs the work mode from the work mode changeover switch 12 and the work mode changeover switch 12 is in the normal mode of the high load mode other than the economy mode or It is determined whether or not the heavy excavation mode is set (S2).

  If the work mode switch 12 is in the normal mode or heavy excavation mode in a high load mode other than the economy mode, the work mode control unit 13 determines whether the work mode switch 12 has been switched to another mode (S3). ). For example, when the excavator 1 has already been operated in the economy mode by the start-up process, when the operator feels uncomfortable with the difference between the operation mode selected by the operation mode change-over switch 12 and the operation state, the operation mode change-over switch 12 again. The work mode control unit 13 determines whether or not an operation such as switching to the normal mode or the heavy excavation mode by operating is performed.

  If the work mode change-over switch 12 is not switched to another mode, the work pressure calculating unit 17 detects the discharge pressure of the hydraulic pump 20 detected by the discharge pressure detecting means 18 when the operation amount of the operating device 22 is equal to or less than a predetermined amount. Is determined to be less than or equal to a predetermined pressure. That is, the work mode control unit 13 determines whether the normal load mode or the heavy excavation mode is output from the work load calculation unit 17 (S4).

  When the operation amount of the operating device 22 is not more than a predetermined amount and the discharge pressure of the hydraulic pump 20 is not more than a predetermined pressure, that is, the work mode control unit 13 is operated by the work load calculation unit 17 from the normal mode or the heavy excavation mode Is not output, the work mode control unit 13 performs start-up processing by the start-up processing means 13a, and outputs the economy mode to the engine speed calculation unit 10. Then, the engine speed calculation unit 10 reads the engine speed in the economy mode from the work mode storage unit 11, and outputs the read engine speed to the engine as the target speed (S5). Then, the work mode control unit 13 displays on the monitor display device 16 that the engine speed is controlled at the economy mode based on the display processing by the display processing means 13b (S6). In this state, for example, light excavation work or the like by the front work machine 4 is performed at an engine speed corresponding to the economy mode.

  On the other hand, if the start time processing by the start time processing means 13a is not valid in step S1, the work mode control unit 13 outputs the work mode selected by the work mode changeover switch 12 to the engine speed calculation unit 10. Receiving this output, the engine speed calculation unit 10 reads the engine speed corresponding to the work mode output from the work mode control unit 13 from the work mode storage unit 11, and uses the read engine speed as the target speed. By outputting as a number, the engine speed is controlled (S7).

  In step S2, if the work mode switch 12 is not the normal mode or heavy excavation mode other than the economy mode, that is, if the work mode switch 12 is in the economy mode, the work mode switch 12 is selected. The economy mode is output to the engine speed calculator 10. The engine speed calculation unit 10 that has received this output reads the engine speed corresponding to the economy mode from the work mode storage unit 11, and outputs the read engine speed as a target speed, thereby outputting the engine speed. The rotational speed is controlled (S7).

  Similarly, if the work mode switch 12 is switched to another mode in step S3, the work mode selected by the work mode switch 12 is output to the engine speed calculator 10. Receiving this output, the engine speed calculation unit 10 reads the engine speed corresponding to the work mode output from the work mode control unit 13 from the work mode storage unit 11, and uses the read engine speed as the target speed. By outputting as a number, the engine speed is controlled (S7).

  In step S4, the operation amount of the operating device 22 is not more than the predetermined amount and the discharge pressure of the hydraulic pump 20 is not less than the predetermined pressure. If the heavy excavation mode is output, the work mode control unit 13 stops the start-up processing by the start-up processing means 13a based on the stop processing by the stop processing means 13d, and the high load selected by the work mode changeover switch 12 The normal mode or the heavy excavation mode is output to the engine speed calculation unit 10. The engine speed calculation unit 10 that has received this output reads out the engine speed corresponding to the normal mode or heavy excavation mode of the high load mode output from the work mode control unit 13 from the work mode storage unit 11. The engine speed is controlled by outputting the read engine speed as the target engine speed (S7). Thereafter, after the process of step S6 or step S7 is completed, the process is repeated from step S1.

  Here, in the case where the steps from Step S3 or Step S4 to Step S7 are repeated, the operator operating the excavator 1 once stops driving the excavator 1, for example, the front work machine 4 in order to interrupt the work. When stopped, the work mode control unit 13 starts the timing process. When, for example, the front work machine 4 is driven again before this time-measured time reaches the predetermined time A, the work mode control unit 13 performs invalidation processing by the invalidation processing unit 13c, and by the start time processing unit 13a. The start-up process is invalidated, and the normal mode or the heavy excavation mode of the high load mode that has been utilized in the previous work is output to the engine speed calculation unit 10. The engine speed calculation unit 10 that has received this output reads out the engine speed corresponding to the normal mode or heavy excavation mode of the high load mode output from the work mode control unit 13 from the work mode storage unit 11. The engine speed is controlled by outputting the read engine speed as the target engine speed.

  According to the present embodiment configured as described above, when the work is completed in the normal mode or the heavy excavation mode in which the previous work mode is the high load mode and the current work content is a light load work, the procedure from step S1 is performed. In S6, the work mode control unit 13 performs start-up processing by the start-time processing means 13a, so that the engine speed calculation unit 10 can control the engine with the engine speed in the economy mode as the target speed. Therefore, when the excavator 1 is started, an economy mode suitable for the work content is automatically set, and excess fuel is not consumed, so that the economy can be improved.

  In addition, when the work is finished while the previous work mode is restricted in the economy mode and the current work content is a high load work, the work mode changeover switch 12 is used to switch to a mode other than the economy mode in step S3 after the excavator 1 is started. In step S7, the work mode control unit 13 outputs the normal mode or the heavy excavation mode selected by the work mode changeover switch 12 to the engine speed calculation unit 10 in step S7. The number calculation unit 10 can control the engine with the engine speed in the normal mode or the heavy excavation mode in the high load mode as the target engine speed. Therefore, the engine speed can be easily changed from the state in which the engine speed is controlled to the economy mode to the normal mode of the high load mode or the heavy excavation mode, and the manager of the excavator 1 or the like can change the work mode. Therefore, it is not necessary to obtain permission for the change, and it is not necessary to make complicated settings, so that convenience can be improved.

  In step S6, the work mode control unit 13 can display on the monitor display device 16 that the engine speed is controlled by the speed of the economy mode by the display processing by the display processing means 13b. In S5, the engine speed is controlled to the economy mode by the start mode processing by the start mode processing unit 13a in S5, and the normal mode or heavy excavation in the high load mode other than the economy mode is switched by the work mode switch 12. Even if the mode is selected, the monitor display device 16 can know that the current state is the economy mode, and can prevent the operator from feeling uncomfortable or concerned about the failure of the hydraulic excavator 1. it can.

  In addition, since the work mode control unit 13 includes the invalidation processing unit 13c, when the steps from the step S3 or the step S4 to the step S7 are repeated, the operator is in the normal mode of the high load mode or the heavy excavation mode. Even if, for example, the front work machine 4 of the excavator 1 is stopped in order to interrupt the work once during the work, the work mode control unit 13 uses the invalidation processing means 13c when the work is resumed before reaching the predetermined time A. By performing the invalidation process, it is possible to continue working in the normal mode of the high load mode or the heavy excavation mode. Thereby, work continuity can be ensured.

  Further, since the external maintenance device 15 can enable or disable the startup process by the startup processing means 13a of the work mode control unit 13, the external maintenance device 15 is connected to the work mode control unit 13 to start processing. By invalidating the start-up process by the means 13a, in step S1, the work mode control unit 13 determines that the start-up process by the start-up processing means 13a is invalid, and proceeds to step S7 as it is. Therefore, when the operator knows in advance that the work content is a high-load work, the normal mode or the heavy excavation mode of the high-load mode can be used from the start of the hydraulic excavator 1, thereby improving convenience. Can do.

  When the operation amount of the operation device 22 is larger than the predetermined amount and the discharge pressure of the hydraulic pump 20 is higher than the predetermined pressure, that is, when the work load is large, the work is output according to the work mode output from the work load calculation unit 17. The mode control unit 13 performs stop processing by the stop processing unit 13d, and automatically outputs a work mode suitable for the work load to the engine speed calculation unit 10 regardless of the work mode selected by the work mode changeover switch 12. Therefore, operability can be improved and fuel consumption can be suppressed.

  In the present embodiment, the case where the external maintenance device 15 is appropriately connected when the start time processing by the start time processing means 13a of the work mode control unit 13 is changed to valid or invalid has been described. The apparatus 15 may be provided in the cab 7 of the excavator and the start time processing by the start time processing means 13a may be changed to valid or invalid by inputting a personal identification number or the like.

  Further, in the present embodiment, the work load calculation unit 17 performs high load work when the operation amount of the operating device 22 is larger than a predetermined amount and the discharge pressure of the hydraulic pump detected by the discharge pressure detecting means 18 is larger than the predetermined pressure. However, the work load calculating unit 17 does not look at the operation amount of the operating device 22 and determines whether or not the work is a high load work only with the discharge pressure of the hydraulic pump 20 detected by the discharge pressure detecting means 18. You may do it.

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 2 Traveling body 3 Revolving body 3a Revolving frame 4 Front work machine 5 Engine room 6 Counterweight 7 Cab 10 Engine speed calculating part 11 Work mode memory | storage part 12 Work mode changeover switch (work mode switching means)
DESCRIPTION OF SYMBOLS 13 Work mode control part 13a Start time processing means 13b Display processing means 13c Invalidation processing means 13d Stop processing means 14 Engine speed adjustment dial 15 External maintenance device 16 Monitor display device 17 Work load calculation portion 18 Discharge pressure detection means 19 Operation amount detection Means 20 Hydraulic pump 21 Directional control valve 22 Operating device 22a Pressure reducing valve 25 Pilot pump

Claims (3)

Provided in a working machine having an engine,
A plurality of operation modes including an engine rotation speed calculation unit for calculating a target rotation speed of the engine, an economy mode which is a mode at light load work, and a high load mode which is higher than the rotation speed of the economy mode. A work mode storage unit that stores the number of rotations according to each of the above, a work mode switching unit that selects any one of the plurality of work modes, and a work mode selected by the work mode switching unit as the engine rotation A work mode control unit that outputs to the number calculation unit, the engine rotation number calculation unit reads out the engine rotation number corresponding to the work mode output from the work mode control unit from the work mode storage unit, In the engine speed control device for a work machine that outputs the read engine speed as the target speed,
The work mode control unit performs start-up processing for outputting the economy mode to the engine speed calculation unit regardless of what work mode is selected by the work mode switching means when the work machine is started. look including the time processing means being connected to the work mode control unit, the external maintenance apparatus for outputting a signal to enable or disable the start-up processing by the startup processing means is provided, the work mode control unit, the When the work machine is stopped from a state where work in the high load mode is being performed and the work machine is started before a certain time has elapsed since the stop, the start time processing by the start time processing means is performed. Including invalid processing means for performing processing of invalidating and outputting the high load mode as the work mode to the engine speed calculation unit; Maintenance device, working machine the engine rotational speed control apparatus which comprises a variably settable setting means the predetermined time.   2. The work machine according to claim 1, wherein the work machine includes a monitor display device capable of displaying a current work mode, and the work mode control unit is configured to switch the work mode control unit to a mode other than the economy mode by the work mode switching unit when the work machine is started. A work machine comprising: a display processing unit configured to display on the monitor display device that the engine speed is controlled by the speed of the economy mode when the work mode is selected; Engine speed control device. 2. The working machine according to claim 1, wherein the work machine includes a hydraulic pump driven by the engine, a hydraulic actuator operated by pressure oil discharged from the hydraulic pump, and a pressure supplied from the hydraulic pump to the hydraulic actuator. A directional control valve for controlling the flow of oil, and an operating device for switching the directional control valve;
The discharge pressure detection means for detecting the discharge pressure of the hydraulic pump, and the work content actually performed by the discharge pressure detection means are determined to correspond to any of the above work modes. A work load calculation unit that outputs a work mode to the work mode control unit;
When the high load mode is output from the work load calculation unit, the work mode control unit stops the start time processing by the start time processing means and outputs the high load mode to the engine speed calculation unit. An engine speed control device for a working machine, comprising stop processing means for performing stop processing .

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