JP2011190788A - Engine control device - Google Patents

Engine control device Download PDF

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Publication number
JP2011190788A
JP2011190788A JP2010060201A JP2010060201A JP2011190788A JP 2011190788 A JP2011190788 A JP 2011190788A JP 2010060201 A JP2010060201 A JP 2010060201A JP 2010060201 A JP2010060201 A JP 2010060201A JP 2011190788 A JP2011190788 A JP 2011190788A
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engine speed
speed
engine
output torque
target engine
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JP5325146B2 (en
Inventor
Teruo Akiyama
Masashi Ichihara
Takeshi Oi
健 大井
将志 市原
照夫 秋山
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Komatsu Ltd
株式会社小松製作所
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine control device which can further reduce fuel consumption, even when the maximum speed of an operating machine is lowered to reduce the fuel consumption. <P>SOLUTION: A first target engine speed is set in accordance with a command value instructed by an instruction means, and based on an operation mode selected by the first target engine speed and an operation mode setting means, a second target engine speed is set to a lower speed than the first target engine speed. The second target engine speed is set to a lower engine speed when a second operation mode is selected than when a first operation mode is selected. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an engine control device that performs engine drive control based on a set target engine speed of an engine, and more particularly to an engine control device that improves engine fuel consumption.

  For construction machinery, when the pump absorption torque is less than the rated torque of the engine, the engine output torque matches the pump absorption torque in the high-speed control area in the engine output torque characteristic line that shows the relationship between the engine speed and the engine output torque. Has been done. For example, the target engine speed is set corresponding to the setting with the fuel dial, and the high speed control region corresponding to the set target engine speed is determined.

  Alternatively, a high speed control region is determined corresponding to the setting with the fuel dial, and a target engine speed of the engine is set corresponding to the determined high speed control region. Then, control for matching the pump absorption torque and the engine output torque is performed in the determined high-speed control region.

  In general, many workers often set the target engine speed to be the rated engine speed or a speed in the vicinity thereof in order to increase the amount of work. By the way, the region where the fuel consumption of the engine is small, that is, the region where the fuel consumption is good, usually exists in the medium speed rotation speed region and the high torque region on the engine output torque characteristic line. For this reason, the high-speed control region determined between the no-load high idle rotation and the rated rotation is not an efficient region from the viewpoint of fuel consumption.

  Conventionally, in order to drive the engine in a fuel-efficient region, the target engine speed value of the engine and the target engine output torque value are set in advance in association with each work mode so that a plurality of work modes can be selected. Such a control device is known (for example, see Patent Document 1). In this type of control device, for example, when the operator selects the second work mode, the engine speed can be set lower than in the first work mode, and fuel consumption is improved. be able to.

  However, when the work mode switching method as described above is used, fuel efficiency cannot be improved unless the operator operates the mode switching means one by one. Also, when the engine speed when the second work mode is selected is set to be a speed that is uniformly reduced with respect to the engine speed when the first work mode is selected. When the second work mode is selected, the following problem occurs.

  That is, the maximum speed of the construction machine working device (hereinafter referred to as a working machine) is lower than that in the case where the first working mode is selected. As a result, the work amount when the second work mode is selected is smaller than the work amount when the first work mode is selected.

  In order to solve such problems, the applicant has already applied for an engine control device and a control method thereof (see Patent Document 2). According to the engine control device, when the pump capacity and the engine output torque are low, the engine drive control is performed based on the second target engine speed that is lower than the set first target engine speed. In response to the pump capacity or the engine output torque, the engine drive control can be performed so that the target engine speed is set in advance.

  According to the above-described invention of the engine control device, there is an effect that the maximum speed of the work implement can be maintained while improving the fuel consumption of the engine.

Japanese Patent Laid-Open No. 10-273919 International Publication No. 2009/104636 Pamphlet

  The invention of the engine control device described in Patent Document 2 described above reduces fuel consumption while maintaining the maximum speed of the work implement.

  The invention of the present application aims to further improve the invention of Patent Document 2, and even if the maximum speed of the work machine is reduced in order to reduce the fuel consumption, further fuel consumption It is an object of the present invention to provide an engine control device that can reduce the above.

The object of the present invention can be suitably achieved by the first to fourth aspects of the engine control apparatus.
That is, in the engine control apparatus according to the first aspect of the present invention, the variable displacement hydraulic pump driven by the engine, the hydraulic actuator driven by the discharge pressure oil from the hydraulic pump, and the pressure oil discharged from the hydraulic pump Of the control valve for supplying and discharging to the hydraulic actuator, detecting means for detecting the pump capacity of the hydraulic pump, a fuel injection device for controlling the fuel supplied to the engine, and command values that can be variably commanded Command means for selecting and commanding one command value, a first work mode for controlling the engine based on a first engine output torque characteristic line defining a relationship between the engine speed and the engine output torque, Based on the second engine output torque characteristic line that defines the engine output torque lower than the engine output torque characteristic line A work mode setting means capable of selecting and commanding a second work mode for controlling the engine; a first target engine speed is set according to a command value commanded by the command means; and the first target engine speed First setting means for setting a second target engine speed that is lower than the first target engine speed based on the number and the work mode selected by the work mode setting means; and the second target Second setting means for setting a target engine speed corresponding to the pump capacity with the engine speed as a lower limit value, and controlling the fuel injection device so as to be the target engine speed determined from the second setting means. Control means, wherein the second target engine speed is set to a lower speed when the second work mode is selected than when the first work mode is selected. It is the most important feature that formed by.

  In the second invention of the present application, when the first work mode is selected by the work mode setting means, a first pump absorption torque limit line for limiting the absorption torque of the hydraulic pump is set, and the second work The main feature is that when the mode is selected, the second pump absorption torque limit line is set on the rotational speed side lower than the first pump absorption torque limit line.

  Further, in the third invention of the present application, the rotation of the second target engine speed when the first work mode is selected and the second target engine speed when the second work mode is selected. The number difference includes a first target matching rotational speed at a matching point that is an intersection of the first engine output torque characteristic line and the first pump absorption torque limit line, the second engine output torque characteristic line, and the second engine output torque characteristic line. The main feature is that the rotational speed difference is set to be equal to or smaller than the second target matching rotational speed at the matching point that is an intersection with the pump absorption torque limit line.

  Furthermore, in the fourth invention of the present application, the difference in engine speed at the maximum output torque point on the first engine output torque characteristic line and the first target matching engine speed is determined by the second engine output torque characteristic. The main feature is that the engine speed at the maximum output torque point on the line is equal to the speed difference between the second target matching speed.

  The engine control apparatus according to the present invention sets the second target engine speed based on the first target engine speed and the selected work mode. When the second work mode in which the engine output torque is suppressed is selected, the second target engine speed can be set to a lower speed than when the first work mode is selected.

  Since the 1st invention of this application is constituted in this way, when the 2nd work mode is selected, fuel consumption efficiency can be improved greatly compared with the time when the 1st work mode is selected.

  By configuring as in the second invention of the present application, the second target engine speed can be set to a lower speed when the second work mode is selected. Thereby, when the second work mode is selected, the fuel efficiency can be further improved.

  By configuring as in the third invention of the present application, the second target engine rotational speed can be set to a rotational speed higher than the target matching rotational speed regulated by the pump absorption torque limit line. As a result, the pressure oil supplied to the actuator does not cause a shortage of flow rate. And even if the worker selects the second work mode, there is no sense of incongruity in the operability of the work implement.

  By configuring as in the fourth invention of the present application, engine stall is likely to occur even when the first work mode is selected or when the second work mode is selected. A desired rotational speed difference can be provided between the engine rotational speed at the maximum output torque point and the target matching rotational speed. As a result, the target matching rotational speed can be set to a rotational speed sufficiently higher than the target engine rotational speed at the maximum output torque point, so that the occurrence of engine stall can be reliably prevented.

1 is a hydraulic circuit diagram according to an embodiment of the present invention. (Example) It is an engine output torque characteristic line. (Example) It is an engine output torque characteristic line when increasing an engine output torque. (Example) It is a block diagram of a controller. (Example) FIG. 5 is an enlarged view showing a correspondence relationship between a first target engine speed and a second target engine speed. (Example) It is the figure which showed the relationship between an engine output torque characteristic line and a pump absorption torque limitation line. (Example) It is a control flow figure concerning the present invention. (Example) It is the figure which showed the relationship between a pump capacity | capacitance and a target engine speed. (Example) It is the figure which showed the relationship between engine output torque and target engine speed. (Example) It is the figure which showed the relationship between an engine speed and an engine output torque. (Example)

  Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. The engine control device of the present invention can be suitably applied as a control device for controlling an engine mounted on a construction machine such as a hydraulic excavator, a bulldozer, or a wheel loader.

  In addition to the shape and configuration described below, the shape and configuration of the engine control device of the present invention can be adopted as long as the shape and configuration can solve the problems of the present invention. Is. For this reason, this invention is not limited to the Example demonstrated below, A various change is possible.

  FIG. 1 is a hydraulic circuit diagram of an engine control apparatus according to an embodiment of the present invention. The engine 2 is a diesel engine, and the engine output torque is controlled by adjusting the amount of fuel injected into the cylinder of the engine 2. This fuel adjustment can be performed by a conventionally known fuel injection device 3. Further, the operation mode can be set to an economy mode, a power mode, or the like by operating the operation mode setting means 44.

  A variable displacement hydraulic pump 6 (hereinafter referred to as a hydraulic pump 6) is connected to the output shaft 5 of the engine 2, and the hydraulic pump 6 is driven by the rotation of the output shaft 5. The tilt angle of the swash plate 6a of the hydraulic pump 6 is controlled by the pump control device 8, and the pump capacity D (cc / rev) of the hydraulic pump 6 changes as the tilt angle of the swash plate 6a changes.

  The pump control device 8 includes a servo cylinder 12 that controls the tilt angle of the swash plate 6a, an LS valve (load sensing valve) 17 that is controlled according to the differential pressure between the pump pressure and the load pressure of the hydraulic actuator 10, It is composed of The servo cylinder 12 includes a servo piston 14 that acts on the swash plate 6a, and pressure oil discharged from the hydraulic pump 6 is supplied through oil passages 27a and 27b. The LS valve 17 operates in accordance with the differential pressure between the hydraulic pressure of the oil passage 27a (pump discharge pressure) and the hydraulic pressure of the pilot oil passage 28 (load pressure of the hydraulic actuator 10), and controls the servo piston 14. Yes.

  By controlling the servo piston 14, the tilt angle of the swash plate 6a in the hydraulic pump 6 is controlled. The control valve 9 is controlled by the pilot pressure output from the operation lever device 11 according to the operation amount of the operation lever 11a. By controlling the control valve 9, the flow rate supplied to the hydraulic actuator 10 is controlled. The pump control device 8 can be configured by a known load sensing control device.

  Further, a pilot pressure is supplied to one end of the LS valve 17 to which the oil pressure (pump discharge pressure) of the oil passage 27a is supplied from the oil passage branched from the oil passage 27a via the electromagnetic proportional valve 16. The electromagnetic proportional valve 16 is configured so that the pilot pressure supplied to one end of the LS valve 17 can be adjusted by a command value from the controller 7. The controller 7 can limit the angle (corresponding to the pump capacity) of the swash plate 6a of the hydraulic pump 6 by controlling the command value of the electromagnetic proportional valve 16.

  Therefore, the controller 7 can limit the pump absorption torque according to the engine speed detected by the engine speed sensor 20 by setting a pump absorption torque limit line described later. The means for limiting the pump absorption torque can be constituted by means other than the above. The means for limiting the pump absorption torque may be limited by providing a conventionally known torque control valve.

  The pressure oil discharged from the hydraulic pump 6 is supplied to the control valve 9 through the discharge oil passage 25. The control valve 9 is configured as a switching valve that can be switched to the 5-port 3 position. By selectively supplying the pressure oil output from the control valve 9 to the oil passages 26a and 26b, the hydraulic actuator 10 Can be activated.

  The hydraulic actuator is not limited to the illustrated hydraulic cylinder type hydraulic actuator, and may be a hydraulic motor, or may be configured as a rotary type hydraulic actuator. Further, only one set of the control valve 9 and the hydraulic actuator 10 is illustrated, but a plurality of sets of the control valve 9 and the hydraulic actuator 10 are configured. Moreover, it can also comprise so that several hydraulic actuators may be operated with one control valve.

  Further, the operation lever device 11 is configured such that, for example, the operation lever 11a can be operated in two operation directions of front and rear and left and right as viewed from the operator, and different control valves can be switched depending on each operation direction. It can also be left.

  As a hydraulic actuator operated by the operation lever device 11, for example, a hydraulic excavator in a construction machine is described as an example. A boom hydraulic cylinder, an arm hydraulic cylinder, a bucket hydraulic cylinder, a left traveling hydraulic motor, a right A traveling hydraulic motor, a turning motor, and the like are used as the hydraulic actuator. In FIG. 1, among these hydraulic actuators, for example, a boom hydraulic cylinder is shown as a representative.

  When the operation lever 11a is operated from the neutral position, pilot pressure is output from the operation lever device 11 according to the operation direction and the operation amount of the operation lever 11a. The output pilot pressure is applied to one of the left and right pilot ports of the control valve 9. As a result, the control valve 9 is switched from the (II) position, which is the neutral position, to the left and right (I) positions or (III) positions.

  When the control valve 9 is switched from the (II) position to the (I) position, the discharge pressure oil from the hydraulic pump 6 can be supplied from the oil passage 26b to the head side of the hydraulic actuator 10, and the piston of the hydraulic actuator 10 Can be stretched. At this time, the pressure oil on the rod side of the hydraulic actuator 10 is discharged from the oil passage 26a through the control valve 9 to the tank 22.

  Similarly, when the control valve 9 is switched to the (III) position, the discharge hydraulic oil from the hydraulic pump 6 can be supplied from the oil passage 26a to the rod side of the hydraulic actuator 10, shortening the piston of the hydraulic actuator 10. Can be made. At this time, the pressure oil on the head side of the hydraulic actuator 10 is discharged from the oil passage 26b to the tank 22 through the control valve 9.

  An oil passage 27c branches off from the middle of the discharge oil passage 25, and an unload valve 15 is disposed in the oil passage 27c. The unload valve 15 is connected to the tank 22 and can be switched between a position for blocking the oil passage 27c and a position for communication. The oil pressure in the oil passage 27c acts as a pressing force for switching the unload valve 15 to the communication position.

  Further, the pilot pressure of the pilot oil passage 28 on which the load pressure of the hydraulic actuator 10 acts and the pressing force of the spring act as a pressing force for switching the unload valve 15 to the shut-off position. The unload valve 15 is controlled by the differential pressure between the pilot pressure of the pilot oil passage 28 and the spring pressing force and the oil pressure in the oil passage 27c.

  Here, when the operator operates the fuel dial 4 as the command means and selects one command value from command values that can be commanded variably, the first target engine speed corresponding to the selected command value is set. can do. According to the first target engine speed set in this way, a high-speed control region that matches the pump absorption torque and the engine output torque can be set.

  That is, as shown in FIG. 2, when the target engine speed Nb, which is the first target engine speed, is set according to the operation of the fuel dial 4, the high speed control region Fb corresponding to the first target engine speed Nb. Will be selected.

  The engine speed N′b is the rotation at the point where the engine output torque matches the total value of the engine friction torque and the hydraulic system loss torque at no load when the target engine speed is set to Nb. Is a number. When the target engine speed Nb is set according to the operation of the fuel dial 4, the point Kb on the engine output torque characteristic line R at the engine speed Nb and the point at no load (engine speed N′b) Is connected as the high-speed control area Fb.

  The target engine speed N′b may be set as the first target engine speed according to the operation of the fuel dial 4, and the high speed control region Fb may be set according to the first target engine speed N′b. .

  Here, when the operator operates the fuel dial 4 to set the first target engine speed Nc lower than the first selected target engine speed Nb, the high speed control on the low speed side is set as the high speed control region. Area Fc is set.

  Thus, by setting the fuel dial 4, one high speed control region can be set corresponding to the first target engine speed that can be selected by the fuel dial 4. That is, by selecting the fuel dial 4, for example, as shown in FIG. 2, a high-speed control region Fa passing through the maximum horsepower point K1 and a plurality of high-speed control regions Fb, Fc on the low speed side from the high-speed control region Fa. ,... Can be set to any high-speed control area, or any high-speed control area in the middle of these high-speed control areas.

  The region defined by the engine output torque characteristic line R in the engine output torque characteristic line of FIG. 3 shows the performance that the engine 2 can produce. The place where the output (horsepower) of the engine 2 becomes maximum is the maximum horsepower point K1 on the engine output torque characteristic line R (hereinafter referred to as the maximum horsepower point K1). M indicates an equal fuel consumption curve of the engine 2, and the center side of the equal fuel consumption curve is the minimum fuel consumption region. K3 on the engine output torque characteristic line R indicates the maximum output torque point at which the torque of the engine 2 is maximum.

  In the following, the first target engine speed N1, which is the maximum target engine speed of the engine, is set corresponding to the command value of the fuel dial 4, and the maximum horsepower point K1 is set corresponding to the first target engine speed N1. The case where the high-speed control region F1 to pass is set will be described as an example.

  Incidentally, in response to the command value of the fuel dial 4 shown in FIG. 1, the first target engine speed N1 which is the rated speed as the engine speed (in FIG. 2, the rated speed is indicated as Nh). In FIG. 3, the first target engine speed N1 is also the rated speed.), A description will be given of a case where the high speed control region F1 passing through the maximum horsepower point K1 corresponding to the first target engine speed N1 is set. Do the following:

  However, the present invention is not limited to the case where the high speed control region F1 passing through the maximum horsepower point K1 is set. For example, as a high-speed control region corresponding to the set first target engine speed, the plurality of high-speed control regions Fb, Fc,... In FIG. Even when an arbitrary high-speed control area is set in the middle, the present invention can be suitably applied to each set high-speed control area.

  FIG. 3 shows how the engine output torque increases. In the present invention, the high-speed control region F1 can be set in accordance with the first target engine speed N1 set by the operator corresponding to the command value at the fuel dial 4. Then, a second target engine speed N2 that is lower than the first target engine speed N1 is set, and engine drive control is performed based on the high-speed control region F2 corresponding to the second target engine speed N2. Has started. The second target engine speed N2 is changed according to the selected work mode as will be described later.

  The controller 7 can be realized, for example, by a computer having a storage device used as a program memory or a work memory and a CPU that executes the program. The storage device of the controller 7 stores Table 1 to Table 3 shown in FIG.

  Next, the control of the controller 7 will be described with reference to the block diagram of FIG. In FIG. 4, the command value of the fuel dial 4 is input to the high-speed control region selection calculation unit 32 in the controller 7 and the pump torque command value required by the hydraulic pump 6 calculated by the pump torque calculation unit 31. The pump displacement detected by the swash plate angle sensor 39 and the determination result from the work mode determination unit 45 are input.

  The pump torque calculation unit 31 includes a pump pressure discharged from the hydraulic pump 6 detected by the pump pressure sensor 38 (pump discharge pressure), and a swash plate angle (pump capacity) of the hydraulic pump 6 detected by the swash plate angle sensor 39. Is entered. The pump torque calculation unit 31 calculates pump torque (engine output torque) from the input swash plate angle of the hydraulic pump 6 and pump pressure of the hydraulic pump 6.

  The pump torque calculation unit 31, the pump pressure sensor 38, and the swash plate angle sensor 39 have a function as detection means for detecting engine output torque. Further, the swash plate angle sensor 39 has a function as detection means for detecting the pump displacement of the hydraulic pump.

That is, generally, the relationship among the pump discharge pressure P (pump pressure P), the discharge capacity D (pump capacity D) and the engine output torque T of the hydraulic pump 6 can be expressed as T = P · D / 200π.
The work mode selected by the work mode setting means 44 is input to the work mode determination unit 45, and it is possible to determine which work mode is selected by the worker. As the work mode, a power mode (first work mode) and an economy mode (second work mode) that regulates the engine output torque to be low can be provided. Moreover, the state in the middle of economy mode and power mode can also be provided as a normal mode as needed, for example.

  In the high-speed control region selection calculating unit 32, based on the input signal from the work mode determining unit 45, the first target engine speed and the second target engine speed as shown in FIGS. The correspondence table corresponding to the type of work mode selected by the work mode setting means 44 is selected from the correspondence table showing the corresponding relationship. For example, when the power mode is selected by the work mode setting means 44, the correspondence table shown in FIG. 5A can be selected, and when the economy mode is selected, the correspondence table shown in FIG. A correspondence table can be selected. When the normal mode provided between the economy mode and the power mode is selected, the correspondence table shown in FIG. 5B can be selected.

  Then, the high-speed control area selection calculation unit 32 instructs the engine 2 to provide a high-speed control area command value for performing drive control of the engine 2. In addition, the correspondence table shown in FIGS. 5A to 5C is an example, and the correspondence table according to the construction machine or the like can be set as appropriate.

  Further, the pump pressure sensor 38 is configured to detect, for example, the pump pressure in the discharge oil passage 25 of FIG. The swash plate angle sensor 39 is configured as a sensor that detects the swash plate angle of the hydraulic pump 6.

  Thus, when the operator operates the fuel dial 4 as the command means and selects one command value from command values that can be variably commanded, the first target engine speed N1 corresponding to the selected command value is selected. Can be set. The high speed control region F1 for matching the pump absorption torque and the engine output torque can be set according to the first target engine speed N1 set in this way.

  The correspondence between the first target engine speed N1 and the second target engine speed N2 is selected from the correspondence table shown in FIGS. 5A to 5C, corresponding to the selected work mode. can do. For example, when the power mode is selected as the work mode, for example, the correspondence table in FIG. 5A can be selected. When the economy mode is selected, for example, the correspondence table in FIG. 5C can be selected.

  When the power mode is selected as the work mode, as shown in FIG. 5A, when the first target engine speed N1 is set to a speed between 2000 rpm and 2000 rpm, The second target engine speed N2 is set to a constant 1800 rpm.

  When the set first target engine speed is 2000 rpm or less and is set between the engine speed 1500 rpm at the maximum horsepower point K3 (see FIG. 3), the set first target engine is set. Corresponding to the decrease in the rotational speed N1, the amount of decrease when the first target engine rotational speed N1 is decreased to the second target engine rotational speed N2 is also linear as shown by the solid line in FIG. It is set to decrease.

  The specific values of the first target engine speed N1 and the second target engine speed N2 shown in FIGS. 5A to 5C are examples, and the present invention is the numerical values shown in FIG. It is not limited to. It can be changed as appropriate according to the characteristics of the engine, hydraulic pump, etc. mounted on the construction machine.

  By configuring in this way, conditions for setting the second target engine speed N2 from the first target engine speed N1 set by the command value of the fuel dial 4 in each set work mode are determined. be able to. In addition, as the command value of the fuel dial 4 is lower, that is, even if the first target engine speed N1 is set lower, the second target engine speed N2 can be similarly set lower.

  Thus, since the correspondence between the first target engine speed N1 and the second target engine speed N2 can be set, the first corresponding to the command value of the fuel dial 4 in each set work mode. If the target engine speed N1 is set, fuel efficiency can be greatly improved.

  In the present invention, the correspondence between the first target engine speed N1 and the second target engine speed N2 corresponds to the work mode selected by the work mode setting means 44 shown in FIGS. The correspondence table shown in (a) to FIG. Then, based on the correspondence table selected from the correspondence tables shown in FIGS. 5A to 5C, the second target corresponding to the first target engine speed N1 set by the command value of the fuel dial 4 is used. The engine speed N2 is set in the high speed control region selection calculation unit 32 shown in FIG.

  For this reason, the high speed control region selection calculation unit 32 sets the first target engine speed N1 in accordance with the command value commanded by the fuel dial 4, and selects the first target engine speed N1 and the work mode setting means 44. A function as a first setting means for setting a second target engine speed N2, which is a lower speed than the first target engine speed N1, is provided on the basis of the work mode.

  Next, a method for determining the second target engine speed will be described with reference to FIG. 6 when the power mode is selected by the work mode setting means and when the economy mode is selected by the work mode setting means. . When the power mode is selected, the engine 2 is controlled based on a first engine output torque characteristic line RP (shown by a dotted line). The first engine output torque characteristic line RP is defined with the maximum output torque point as K3P and the maximum horsepower point as K1P.

  When the economy mode is selected, the engine 2 is controlled based on a second engine output torque characteristic line RE (shown by a solid line) in which the engine output torque is limited to be lower than the first engine output torque characteristic line RP. . The second engine output torque characteristic line RE is defined with the maximum output torque point as K3E and the maximum horsepower point as K1E.

  The hydraulic pump 6 is controlled based on the pump absorption torque limit line (PcP, PcE). The pump absorption torque limit line is provided for adjusting engine horsepower and preventing engine stall. The controller 7 controls the angle of the swash plate 6a of the hydraulic pump 6 so that the engine output torque does not exceed the pump absorption torque limit line, according to the engine speed measured by the engine speed sensor 20.

  Accordingly, the controller 7 controls the swash plate of the hydraulic pump 6 within a range not exceeding the set pump absorption torque limit line. The engine speed and engine output torque can be controlled by limiting the upper limit of the capacity of the hydraulic pump 6. The pump absorption torque limit line is designed to be a monotonically increasing function in which the engine output torque increases as the engine speed increases with the engine speed as a variable.

  Hereinafter, a case where the power mode is selected by the work mode setting unit 44 will be described. When the power mode is selected, a second target engine speed N2P that is lower than the first target engine speed N1 set according to the command value of the fuel dial 4 is set. The engine 2 is controlled along a high speed control area F2P corresponding to the second target engine speed N2P, and when the pump capacity or the engine output torque becomes larger than a predetermined value, the high speed control area F1 corresponding to the first target engine speed N1. Is controlled along.

  The second target engine speed N2P is preferably set as follows. The lower the second target engine speed that is lower than the first target engine speed N1, the greater the effect of reducing fuel consumption. However, when the second target engine rotational speed is set lower than the predetermined rotational speed, the hydraulic actuator may be insufficient in flow rate to be supplied and cause malfunction.

  Explaining in FIG. 6, when N2E, which is the second target engine speed lower than N2P, is set, a sudden load is applied when engine 2 outputs engine output torque at point L2E. Think about the time. At this time, the engine output torque of the engine 2 suddenly increases from the engine output torque state at the L2E point toward the K2E point. However, the engine output torque interferes with the first pump absorption torque characteristic line PcP at the point X. As a result, the pump absorption torque of the hydraulic pump 6 is limited, so that the pump capacity is limited. Therefore, the hydraulic actuator 10 causes a malfunction due to a decrease in the supplied flow rate.

  Therefore, the second target engine speed is preferably equal to or higher than the engine speed N2P (including the vicinity of N2P) at the intersection Y2P between the first engine output torque characteristic line RP and the first pump absorption torque limit line PcP. Further, considering the reduction in fuel consumption, the second target engine speed is preferably N2P (including the vicinity of N2P).

  Next, the case where the economy mode is selected by the work mode setting means 44 will be described below. When the economy mode is selected, the second target engine speed that is lower than the first target engine speed N1 set according to the command value of the fuel dial 4 is set as follows. When the economy mode is selected, the engine is controlled based on a second engine output torque characteristic line RE that defines an engine output torque lower than that of the first engine output torque characteristic line RP.

  Accordingly, when the same first pump absorption torque limit line PcP as when the power mode is selected is set, the second target engine speed is determined by the second engine output torque characteristic line RE and the first pump absorption torque limit line PcP. Is preferably set to the engine speed N2E ′ at the intersection Y2E ′. The engine 2 is controlled along a high speed control region F2E ′ corresponding to the engine speed N2E ′.

  Here, the economy mode is a mode in which fuel consumption is reduced instead of lowering workability than in the power mode. Therefore, the matching rotational speed, which is the intersection of the pump absorption torque limiting line and the engine output torque limiting line, can be set at a lower rotational speed than in the power mode and with good fuel efficiency. Therefore, in the economy mode, the second pump absorption torque limit line PcE can also be set on the rotational speed side lower than the first pump absorption torque limit line PcP.

  Thus, even if the second target engine speed is reduced to the engine speed N2E at the intersection Y2E between the second engine output torque characteristic line RE and the second pump absorption torque limit line PcE, the pressure oil to the hydraulic actuator 10 is reduced. There is no shortage of flow. That is, the second target engine speed is preferably N2E (including the vicinity of N2E) or more. Further, considering the reduction of fuel consumption, the second target engine speed is preferably N2E (including the vicinity of N2E). The engine 2 is controlled along a high speed control region F2E corresponding to N2E.

  The rotational speed difference between the second target engine speed N2P when the power mode is selected and the second target engine speed N2E when the economy mode is selected is the first engine output torque characteristic line RP and the first At the first target matching rotational speed at the matching point Y2P, which is the intersection with the pump absorption torque limit line PcP, and at the matching point Y2E, which is the intersection between the second engine output torque characteristic line RE and the second pump absorption torque limit line PcE It is preferable that the rotation speed difference is set to be equal to or smaller than the second target matching rotation speed.

  With this configuration, the second target engine speed can be set to a higher speed than the target matching speed that is regulated by the pump absorption torque limit line. As a result, the pressure oil supplied to the actuator does not cause a shortage of flow rate. And even if an operator selects economy mode, there is no sense of incongruity in the operativity of a working machine.

  Also, the difference in engine speed between the maximum engine output torque point K3P and the first target matching engine speed N2P on the first engine output torque characteristic line RP is the maximum engine output torque point on the second engine output torque characteristic line RE. It is preferably equal to (including substantially equal to) the difference between the engine speed at K3E and the second target matching speed N2E.

  With this configuration, the engine rotation at the maximum output torque point at which engine stall is likely to occur even when the power mode is selected or the economy mode is selected. A desired rotational speed difference can be provided between the number and the target matching rotational speed. As a result, the target matching rotational speed can be set to a rotational speed sufficiently higher than the target engine rotational speed at the maximum output torque point, so that the occurrence of engine stall can be reliably prevented.

  In this way, even if the economy mode is selected as the work mode, the engine drive control can be started from a state in which the engine speed is lowered without adversely affecting the operation of the actuator. can do. And in order to increase the fuel consumption reduction effect, even if the second target engine speed is decreased, it is possible to prevent a shortage of flow caused by the decrease in the second target engine speed. .

Next, engine drive control will be described with reference to FIG.
In the following, the case where the power mode is selected as the work mode will be described with reference to FIG. 3, but even when the economy mode is selected as the work mode, the same as when the power mode is selected as the work mode. In addition, engine drive control can be performed.

  That is, in the following description, when the economy mode is selected as the work mode, N2E is set as the second target engine speed and F2E is set as the high speed control region as shown in FIG. become. Moreover, the case where the economy mode is selected can be described by replacing the code in the power mode shown in FIG. 6 with the code in the economy mode.

  As the drive control of the engine 2, when the control along the high speed control region F2 based on the second target engine speed N2 is being performed, the pump capacity D of the hydraulic pump 6 is set to a first pump capacity D1 (see FIG. 3 shows a state in which the first pump displacement D1 is reached as the first set position B. Control is performed along the high-speed control region F2 until the first set position B is reached. That is, until the engine output torque reaches the first set position B, the control along the high speed control region F2 is performed.

  When the pump capacity D of the hydraulic pump 6 becomes equal to or greater than the first pump capacity D1, the target engine speed N of the engine 2 is obtained based on the correspondence relationship between the pump capacity D and the target engine speed N. It will be.

  In this way, the engine 2 is controlled to shift from the high speed control region F2 to the high speed control region F1 in accordance with the target engine speed N corresponding to the pump capacity. Then, the pump capacity D of the hydraulic pump 6 driven by the engine 2 is set to a second pump capacity D2 (D2> D1) set in advance (in FIG. 3, the second setting capacity A is the second pump capacity D2). In this case, the drive control of the engine 2 is performed along the high speed control region F1 based on the first target engine speed N1. That is, when the engine output torque reaches the second set position A, control along the high speed control region F1 is performed.

  If the load on the hydraulic actuator 10 increases after the shift to the high speed control region F1, the engine output torque increases along the high speed control region F1. In the high speed control region F1, when the load of the hydraulic actuator 10 increases, the pump capacity D of the hydraulic pump 6 increases to the maximum pump capacity, and the engine output torque increases to the maximum horsepower point K1.

  In addition, during the transition between the high speed control region F1 and the high speed control region F2, when the load of the hydraulic actuator 10 increases and the engine output torque T increases to the engine output torque characteristic line R, or the high speed control region F1 After that, the engine speed and the engine output torque are matched on the engine output torque characteristic line R.

Next, the control flow shown in FIG. 7 will be described.
In the following description of the control flow, the case where the economy mode is selected as the work mode is described. However, when the power mode is selected, the second target engine speed N2E in FIG. 6 is read as the second target engine speed N2P, the high speed control area F2E is read as the high speed control area F2P, and FIG. By replacing the codes in the economy mode shown in FIG. 5 with the codes in the power mode, the same control as when the economy mode is selected can be performed. Therefore, the description of the case where the power mode is selected is omitted.

When the controller 7 reads the information on the work mode selected by the work mode setting means 44 in step S1 in FIG. 7, the process proceeds to step S2.
In step S2, based on the information from the work mode determination unit 45, work mode setting means 44 is selected from the correspondence table candidates of the first target engine speed and the second target engine speed shown in Table 1 or FIG. Select the correspondence table corresponding to the work mode selected in. When the correspondence table is selected, the process proceeds to step S3.

  In step S3, the controller 7 sets a target matching point according to the selected correspondence table. That is, as shown in FIG. 6, the difference between the engine speed N2P at the matching point Y2P and the engine speed at the maximum output torque point K3P on the first engine output torque characteristic line RP is the second engine output torque characteristic. The target matching point Y2E is set so as to be equal to (including substantially equal to) the rotational speed difference between the engine speed at the matching point Y2E on the line RE and the engine speed at the maximum output torque point K3E.

  Since the target matching point Y2E can be set as the intersection of the second engine output torque characteristic line RE and the pump absorption torque limit line PcE, setting the target matching point Y2E sets the pump absorption torque limit line PcE It is also to do. Further, when the target matching point Y2E is set, a preferable rotational speed of the second target engine rotational speed can be determined.

When the target matching point is set in step S3, the process proceeds to step S4.
In step S4, the controller 7 reads the command value of the fuel dial 4. When the command value is read, the process proceeds to step 5.

  In step S5, the controller 7 sets the first target engine speed N1 according to the read command value of the fuel dial 4, and sets the high speed control region F1 based on the set first target engine speed N1. .

  It is explained that the first target engine speed N1 of the engine 2 is first set according to the read command value of the fuel dial 4, but first, the high speed control region F1 is set and set. The first target engine speed N1 can be set corresponding to the high-speed control region F1. Alternatively, the first target engine speed N1 and the high speed control region F1 can be set at the same time in accordance with the read command value of the fuel dial 4.

As shown in FIG. 3, when the first target engine speed N1 and the high speed control region F1 are set, the process proceeds to step S6.
In step S6, the controller 7 selects the first target engine speed N1, the second target engine speed N2E corresponding to the high speed control region F1, the first target engine speed N2E based on the correspondence table selected from Table 1 or the correspondence table shown in FIG. 2 Set the high-speed control region F2E corresponding to the target engine speed N2E. At this time, the second target engine speed N2E is set to be a target matching speed at the target matching point set in step S3 or a speed close to the target matching speed.

In addition, the numerical value of the rotation speed shown in Table 1 and FIG. 5 is an example, and can be appropriately set according to the construction machine.
When the high speed control area F2E is set by the controller 7, the process proceeds to step S7.

  In step S7, in Table 2 for setting the target engine speed from the pump capacity and Table 3 for setting the target engine speed from the engine output torque, the first target engine speed N1 is the upper limit value and the second target engine speed N2E is the lower limit value. Correction is performed to obtain a value. Then, the process proceeds to step S8.

In step S8, drive control of the engine 2 along the high speed control region F2E corresponding to the set second target engine speed N2E is started, and the process proceeds to step S9 or step S12.
When drive control of the engine 2 is performed at the target engine speed N corresponding to the detected pump capacity D, control from step S9 to step S11 is performed. When drive control of the engine 2 is performed at the target engine speed N corresponding to the detected engine output torque T, control from step S12 to step S15 is performed.

First, the control step for obtaining the target engine speed corresponding to the detected pump displacement from step S9 to step S11 will be described.
In step S9, the pump capacity D of the hydraulic pump 6 is read based on the swash plate angle detected by the swash plate angle sensor 39. In step S9, when the pump displacement D is read, the process moves to step S10.

  The outline of the control for obtaining the target engine speed N corresponding to the detected pump displacement D in step S10 is as follows. That is, as shown in FIG. 8, when the engine is controlled based on the second target engine speed N2E, the second target until the pump capacity D of the hydraulic pump 6 reaches the predetermined first pump capacity D1. It is controlled based on the engine speed N2E.

  When the detected pump capacity D is equal to or greater than the first pump capacity D1, the detected pump capacity D is determined based on the correspondence between the preset pump capacity D and the target engine speed N as shown in FIG. The corresponding target engine speed N is determined. At this time, the drive control of the engine 2 is controlled so as to be the obtained target engine speed Nn.

  Until the target engine speed Nn reaches the first target engine speed N1 or the second target engine speed N2E, the target engine speed Nn corresponding to the detected pump capacity Dn is always obtained. Thus, the drive of the engine 2 is always controlled at the determined target engine speed Nn. In this control, the high-speed control region selection calculation unit 32 has a function as second setting means for setting the target engine speed corresponding to the pump capacity with the second target engine speed N2E as a lower limit value. .

  For example, when the pump capacity D detected at the present time is the pump capacity Dn, the target engine speed N can be obtained as the target engine speed Nn. If it is detected that the pump capacity Dn is changed to the pump capacity Dn + 1, the target engine speed Nn + 1 corresponding to the pump capacity Dn + 1 is newly obtained from FIG. Then, drive control for the engine 2 is performed so that the newly obtained target engine speed Nn + 1 is obtained.

  When the detected pump capacity D reaches a predetermined second pump capacity D2, the drive control of the engine 2 is performed along the high speed control region F1 based on the first target engine speed N1. When the drive control of the engine 2 is being performed based on the first target engine speed N1, the high speed control region F1 is maintained until the pump capacity D of the hydraulic pump 6 becomes equal to or less than the second pump capacity D2. The drive control of the engine 2 continues to be performed.

  Returning to FIG. 7, the description of the control step S10 will be continued. In step S10, when the target engine speed N corresponding to the detected pump capacity D is obtained based on the correspondence relationship between the preset pump capacity D and the target engine speed N shown in Table 2, the process proceeds to step S11.

In step S11, the value of the target engine speed N is corrected according to the rate of change of the pump capacity of the hydraulic pump 6, the rate of change of the pump discharge pressure, or the rate of change of the engine output torque T. That is, when the rate of change, that is, the degree of increase is high, the target engine speed N can be corrected to the higher side.
In addition, although the control step which corrects the value of the target engine speed N is described as step S11, the control of step S11 may be skipped.

Next, the control step for obtaining the target engine speed corresponding to the detected engine output torque from step S12 to step S15 will be described.
When the detection signal from the swash plate angle sensor 39 and the detection signal from the pump pressure sensor 38 are read in step S12, the process proceeds to step S13.
In step S13, the engine output torque T is calculated based on the pump displacement and pump pressure detection signals read in step S12. When the engine output torque T is calculated, the process proceeds to step S14.

  The outline of the control for obtaining the target engine speed N corresponding to the detected engine output torque T in step S14 is as follows. That is, as shown in FIG. 9, when the engine is controlled on the basis of the second target engine speed N2E, the engine is in a first state until the detected engine output torque T becomes a predetermined first engine output torque T1. It is controlled based on the two target engine speed N2E.

  When the detected engine output torque T is equal to or greater than the first engine output torque T1, it is detected based on the correspondence between the preset engine output torque T and the target engine speed N as shown in FIG. The target engine speed N corresponding to the engine output torque T is obtained. At this time, the drive control of the engine 2 is controlled so that the obtained target engine speed N is obtained.

  Until the target engine speed N reaches the first target engine speed N1 or the second target engine speed N2E, the target engine speed N corresponding to the detected engine output torque T is always obtained. Thus, the drive control of the engine 2 is performed according to the obtained target engine speed N.

  For example, when the engine output torque T detected at the present time is the engine output torque Tn, the target engine speed Nn is obtained as the target engine speed N. If it is detected that the engine output torque T has changed from the engine output torque Tn state to the engine output torque Tn + 1 state, the target engine speed Nn + 1 corresponding to the engine output torque Tn + 1 is obtained. Newly required. Then, drive control for the engine 2 is performed so that the newly obtained target engine speed Nn + 1 is obtained.

  When the detected engine output torque T becomes the predetermined second engine output torque T2, the drive control of the engine 2 is performed along the high speed control region F1 based on the first target engine speed N1. Become. When the drive control of the engine 2 along the high speed control region F1 is being performed, the engine 2 along the high speed control region F1 is detected until the detected engine output torque T becomes equal to or less than the second engine output torque T2. The drive control continues.

  Further, by obtaining the target engine speed N corresponding to the detected engine output torque T and performing drive control of the engine 2, as shown in FIG. 10, the maximum that the engine 2 can output on the engine output torque characteristic line is shown. The horsepower point K1E can be passed.

  Further, by obtaining the target engine speed N corresponding to the detected engine output torque T and performing drive control of the engine 2, as shown in FIG. 10, the maximum that the engine 2 can output on the engine output torque characteristic line is shown. The horsepower point can be passed.

  Returning to FIG. 7, the description of the control step S14 will be continued. In step S14, when the target engine speed N corresponding to the detected engine output torque T is obtained based on Table 3 showing the correspondence between the preset engine output torque T and the target engine speed N, step S15 is performed. Move on.

In step S15, the value of the target engine speed N is corrected according to the change rate of the pump capacity of the hydraulic pump 6, the change rate of the pump discharge pressure, or the change rate of the engine output torque T. That is, when the rate of change, that is, the degree of increase is high, the target engine speed N can be corrected to the higher side.
In addition, although the control step which corrects the value of the target engine speed N is described as step S15, the control of step S15 may be skipped.

  Of the target engine speed N corresponding to the detected pump capacity D and the target engine speed N corresponding to the detected engine output torque T, when using the target engine speed with the higher speed, Both the control of step S9 to step S11 and the control of step S12 to step S15 are performed. In this case, control of step S16 is performed after step S11 and step S15 are complete | finished.

  When drive control of the engine 2 is performed with the target engine speed N corresponding to the detected pump capacity D, or when drive control of the engine 2 is performed with the target engine speed N corresponding to the detected engine output torque T Skips the control of step S16 and moves to step S17.

  In step S16, the target engine speed having the higher speed is selected from the target engine speed N corresponding to the detected pump capacity D and the target engine speed N corresponding to the detected engine output torque T. Is done. When the higher target engine speed is selected, the process proceeds to step S17.

  In step S17, in order to perform engine drive control using the target engine speed N, the high-speed control region command value is output from the high-speed control region selection calculation unit 32 shown in FIG. When the control in step S17 is performed, the control returns to step S1, and the control starting from step S1 is repeatedly performed.

  Next, control during work will be outlined with reference to FIG. That is, for example, when the operator selects the power mode as the work mode and deeply operates the operation lever 11a to increase the working speed of the hydraulic excavator, the pump displacement D is detected. The control to be performed will be described.

  In the following description using FIG. 3 and FIG. 6 (FIG. 6 shows the configuration more clearly), the case where the power mode is selected as the work mode is described. However, when the economy mode is selected, the second target engine speed N2P in FIG. 6 is read as the second target engine speed N2E, the high speed control area F2P is read as the high speed control area F2E, and FIG. By replacing the code in the power mode shown in Fig. 5 with the code in the economy mode, it is possible to perform the same control as when the power mode is selected. Therefore, the description when the economy mode is selected is omitted.

  Although description of the control performed by detecting the engine output torque T is omitted, the same control as the control for detecting the pump displacement D is performed. In addition, when the economy mode is selected as the work mode, the second target engine speed is set low, but the power mode is selected for engine drive control starting from the second target engine speed. The drive control similar to the case is performed.

  It is assumed that when the power mode is selected by the work mode setting means 44 in FIG. 1 and the operation lever 11a is operated deeply, the control valve 9 is switched to, for example, the (I) position. At this time, the opening area 9a at the (I) position of the control valve 9 increases, and the differential pressure between the pump discharge pressure in the discharge oil passage 25 and the load pressure in the pilot oil passage 28 decreases. Further, the pump control device 8 configured as a load sensing control device operates in a direction to increase the pump capacity D of the hydraulic pump 6.

  The first target engine speed N1 and the high speed control region F1 can be set by setting the fuel dial 4. Then, for example, the correspondence between the first target engine speed N1 and the second target engine speed N2 (N2P in FIG. 6), which are the rated engine speed, depends on the work mode selected by the work mode setting means 44. Can be set.

  In the high-speed control region F2 (F2P in FIG. 6), the operator operates the operation lever 11a further in order to increase the work implement speed from the state where the pump capacity of the hydraulic pump 6 becomes the first pump capacity D1. When this is done, the drive control of the engine 2 is performed so that the target engine speed N corresponding to the detected pump capacity D is obtained. At this time, control is sequentially performed to shift to the optimum high-speed control region between the high-speed control region F2 (F2P in FIG. 6) and the high-speed control region F1.

  When the load on the hydraulic actuator 10 increases after the shift to the high speed control region F1, the engine output torque increases. In the high speed control region F1, when the load of the hydraulic actuator 10 increases, the engine output torque rises to the maximum horsepower point K1. Further, when the load of the hydraulic actuator 10 further increases between the high speed control region F1 and the high speed control region F2 (F2P in FIG. 6), the engine output torque T rises to the engine output torque characteristic line R. When the engine speed increases from the high speed control region F1 to the maximum horsepower point K1, the engine speed and the engine output torque are matched on the engine output torque characteristic line R thereafter.

Since it can change in this way, when the shift to the high-speed control region F1 is performed, the work machine can be driven with the maximum horsepower as usual.
That is, when shifting from the high-speed control region F2 (F2P in FIG. 6) to the high-speed control region F1, ascending control toward the engine output torque characteristic line R is performed as indicated by the dotted line L1 in FIG. become. Further, the state indicated by the dotted line L2 rises directly from the high speed control region Fn during the shift from the high speed control region F2 (F2P in FIG. 6) to the high speed control region F1 toward the engine output torque characteristic line R. Shows control. The state indicated by the arrow of the dotted line L3 shows a state where the control is performed in the state of the conventional high speed control region F1. In the high speed control region Fn, the target engine speed N varies depending on the detected pump displacement D or the detected engine output torque T, so the high speed control region Fn also varies.

  In the above-described embodiment, the example of the hydraulic circuit including the load sensing control device as the hydraulic circuit has been described. However, even if the hydraulic circuit is configured as an open center type, the same can be done.

  As described above, in the present invention, the high-speed control region F1 is set according to the first target engine speed N1 set in accordance with the command value at the fuel dial 4 to increase the fuel efficiency of the engine, According to the target engine speed N1, the high speed control region F1 and the work mode selected by the work mode setting means 44, a second target engine speed N2 (N2E in FIG. 6) on the low speed side set in advance and A high speed control region F2 (F2E in FIG. 6) is set, and engine drive control is performed based on the second target engine speed N2 (N2E in FIG. 6) or the high speed control region F2 (F2E in FIG. 6). Can start.

  In addition, by using a correspondence table of the first target engine speed N1 and the second target engine speed N2 (N2E in FIG. 6) preset according to the work mode selected by the work mode setting means 44, It is possible to set a reduction range when lowering the first target engine speed N1 to the second target engine speed N2 (N2E in FIG. 6).

  As described above, in the present invention, in a region where high engine output torque is not required, the engine speed can be controlled based on the second target engine speed N2 (N2E in FIG. 6) on the low speed side. Moreover, when the economy mode is selected by the work mode setting means 44, the second target engine speed can be set lower than when the power mode is selected. Thus, when the economy mode is selected, the fuel efficiency of the engine can be greatly increased.

  In areas where large pump capacity or high engine output torque is required, engine drive control can be performed so that the target engine speed N is preset according to the detected pump capacity D. The working speed required for operating the machine can be sufficiently obtained.

  Also, when the engine output torque T is decreased from the high output state of the engine, the engine drive control is performed so that the target engine speed N is set in advance according to the detected pump capacity D. Thus, the fuel consumption can be improved.

  The present invention can apply the technical idea of the present invention to engine control for a diesel engine.

  2 ... Engine, 3 ... Fuel injection device, 4 ... Fuel dial (command means), 6 ... Variable displacement hydraulic pump, 7 ... Controller, 8 ... Pump control device, 9 ... Control valve, 11 ... Control lever device, 11a ... Control lever, 12 ... Servo cylinder, 17 ... LS valve, 32 ... High-speed control area selection calculation unit, 44 ... Work mode setting means, 45... Work mode determination unit, F1, F2, F2P, F2E, F2E ', Fa to Fc ... high speed control area, A ... second set position, B ... first Setting position, Nh ... Rated speed, K1 ... Maximum horsepower point, K3, K3P, K3E ... Maximum output torque point, RP ... First engine output torque characteristic line, RE ... Second Engine output torque characteristic line, M ... fuel consumption curve.

Claims (4)

  1. A variable displacement hydraulic pump driven by an engine;
    A hydraulic actuator driven by pressure oil discharged from the hydraulic pump;
    A control valve for controlling the pressure oil discharged from the hydraulic pump to supply and discharge to the hydraulic actuator;
    Detecting means for detecting a pump capacity of the hydraulic pump;
    A fuel injection device for controlling fuel supplied to the engine;
    Command means for selecting and commanding one command value from command values that can be commanded variably;
    A first working mode for controlling the engine based on a first engine output torque characteristic line that defines the relationship between the engine speed and the engine output torque, and an engine output torque that is defined lower than the first engine output torque characteristic line. A work mode setting means capable of selecting and commanding a second work mode for controlling the engine based on the second engine output torque characteristic line;
    A first target engine speed is set according to the command value commanded by the command means, and the first target engine speed is set based on the first target engine speed and the work mode selected by the work mode setting means. First setting means for setting a second target engine speed that is lower than the engine speed;
    Second setting means for setting a target engine speed corresponding to the pump capacity, with the second target engine speed as a lower limit;
    Control means for controlling the fuel injection device so as to achieve the target engine speed determined from the second setting means,
    The engine control is characterized in that the second target engine speed is set to a lower speed when the second work mode is selected than when the first work mode is selected. apparatus.
  2.   When the first work mode is selected by the work mode setting means, a first pump absorption torque limit line for limiting the absorption torque of the hydraulic pump is set, and when the second work mode is selected, The engine control device according to claim 1, wherein a second pump absorption torque limit line is set on a lower rotational speed side than the first pump absorption torque limit line.
  3.   The difference in rotation speed between the second target engine speed when the first work mode is selected and the second target engine speed when the second work mode is selected is the first engine speed. A first target matching rotational speed at a matching point that is an intersection of the output torque characteristic line and the first pump absorption torque limit line, and an intersection of the second engine output torque characteristic line and the second pump absorption torque limit line The engine control device according to claim 2, wherein the engine control device is set to be equal to or less than a difference between the second target matching rotation speed at the matching point.
  4.   The rotational speed difference between the engine speed at the maximum output torque point on the first engine output torque characteristic line and the first target matching speed is the maximum output torque point on the second engine output torque characteristic line. 4. The engine control device according to claim 3, wherein the engine speed is equal to a difference between the engine speed and the second target matching speed.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015071975A (en) * 2013-10-03 2015-04-16 日立建機株式会社 Work vehicle

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0783084A (en) * 1993-09-16 1995-03-28 Hitachi Constr Mach Co Ltd Hydraulic construction machine
JPH10273919A (en) * 1997-12-22 1998-10-13 Komatsu Ltd Control device for construction machine
JP2006112280A (en) * 2004-10-13 2006-04-27 Hitachi Constr Mach Co Ltd Control device for hydraulic construction machine
JP2007113304A (en) * 2005-10-21 2007-05-10 Komatsu Ltd Hydraulic driving device
WO2008087847A1 (en) * 2007-01-18 2008-07-24 Komatsu Ltd. Engine control device, and its control method
JP2008190506A (en) * 2007-02-07 2008-08-21 Komatsu Ltd Control device for engine and its control method
WO2009104636A1 (en) * 2008-02-18 2009-08-27 株式会社小松製作所 Engine control device and engine control method

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0783084A (en) * 1993-09-16 1995-03-28 Hitachi Constr Mach Co Ltd Hydraulic construction machine
JPH10273919A (en) * 1997-12-22 1998-10-13 Komatsu Ltd Control device for construction machine
JP2006112280A (en) * 2004-10-13 2006-04-27 Hitachi Constr Mach Co Ltd Control device for hydraulic construction machine
JP2007113304A (en) * 2005-10-21 2007-05-10 Komatsu Ltd Hydraulic driving device
WO2008087847A1 (en) * 2007-01-18 2008-07-24 Komatsu Ltd. Engine control device, and its control method
JP2008190506A (en) * 2007-02-07 2008-08-21 Komatsu Ltd Control device for engine and its control method
WO2009104636A1 (en) * 2008-02-18 2009-08-27 株式会社小松製作所 Engine control device and engine control method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015071975A (en) * 2013-10-03 2015-04-16 日立建機株式会社 Work vehicle

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