JP6872510B2 - Work machine - Google Patents

Description

The present invention relates to a working machine.

A hydraulic excavator, which is a kind of work machine, is used in various situations. For example, it is used for various operations such as excavation work, loading work on a dump truck, and ground leveling work. In recent years, fuel efficiency has been required for work machines from the viewpoint of environmental problems and running costs.

Therefore, as a technique for reducing fuel consumption of such a work machine, for example, in Patent Document 1, a fuel remaining amount sensor for detecting the remaining amount of fuel in the fuel tank and a fuel detected by the fuel remaining amount sensor are described. Based on the value, the fuel consumption calculation unit that calculates the actual fuel consumption as the fuel consumption per unit time by calculating the amount of fuel actually consumed from a certain point in the past to the present time, and this fuel consumption calculation unit obtains it. Construction equipped with a comparison unit that compares the actual fuel consumption with the target fuel consumption stored in advance, and an operation control unit that controls the engine speed and switches the construction machine to energy-saving operation when the actual fuel consumption falls below the target fuel consumption. A fuel-efficient operating device for a machine is disclosed.

Japanese Unexamined Patent Publication No. 2002-285890

By the way, at the site where the work machine operates, it is required to complete the work within a predetermined construction period, so it is necessary to secure a work speed, that is, a so-called maximum work speed, which greatly affects the progress of the work by the work machine. is there. However, in the above-mentioned conventional technique, since the actual fuel consumption is brought closer to the target fuel consumption by limiting the engine speed, it is considered that the maximum working speed is greatly reduced, which greatly delays the working process. In addition to the concern, it is also possible that the fuel consumption required to complete the work will not change as a result of the longer work time. In addition, in work machines, there are various situations where the force and speed of the excavator are required, and the fuel consumption varies greatly depending on the work content and the operation method of the operator. There is a concern that the effect of

The present invention has been made in view of the above, and an object of the present invention is to provide a work machine capable of suppressing fuel consumption while suppressing a decrease in work speed.

The present application includes a plurality of means for solving the above problems, for example, a prime mover, one or more variable displacement hydraulic pumps driven by the prime mover, and discharge from the hydraulic pump. Output from a plurality of hydraulic actuators driven by pressure oil, a front device driven by the plurality of hydraulic actuators, a plurality of operating devices for operating the plurality of actuators, and the plurality of operating devices. A flow rate control valve that controls the flow rate of pressure oil supplied from the hydraulic pump to the plurality of hydraulic actuators based on an operation signal, an operation amount detection device that detects an operation signal output from the operation device, and the above. A vehicle body controller that outputs a pump torque command value for controlling the operation of the hydraulic pump according to a characteristic line showing the relationship between the discharge pressure and the discharge flow rate in the hydraulic pump so that the absorption horsepower of the hydraulic pump becomes a predetermined value. The vehicle body controller is determined based on the presence / absence and operation amount of each of the plurality of operation devices based on the operation signal of the operation device detected by the operation amount detection device. An operation state determination unit that determines which of the plurality of operation states of the front device is, and an operation ratio that calculates an operation ratio that is a ratio of fuel consumption for each operation state in a predetermined period. The calculation unit, the target fuel pressure reduction coefficient calculation table in which the target fuel pressure reduction coefficient corresponding to each of the plurality of operating states is determined for each operation ratio in consideration of the working speed and the degree of fuel pressure reduction, and the operation ratio calculation unit. The target fuel pressure reduction coefficient calculation unit that calculates the target fuel pressure reduction coefficient for each of the plurality of operating states using the operation ratio calculated in the above, and the target hydraulic pump input in advance as the target hydraulic pump by the operator of the work machine. Based on the reduction rate, the target fuel consumption reduction coefficient calculated by the target fuel consumption reduction coefficient calculation unit, and the preset ratio of the target fuel consumption reduction coefficient and the pump output reduction rate basic value, the plurality of operating states. a pump output reduction rate calculation unit that calculates the pump output reduction ratio in each, of the previous SL plurality of pump output reduction rate calculated by the pump output reduction rate calculating unit, the determined said operation by said operation state determining section It shall have a pump torque control command correction unit that corrects the pump torque command value based on the pump output reduction rate corresponding to the state.

According to the present invention, it is possible to suppress fuel consumption while suppressing a decrease in working speed.

It is a side view which shows typically the appearance of the hydraulic excavator which is an example of a work machine. It is a figure which shows typically the main part of the hydraulic circuit system by extracting it together with the related structure of this invention. It is a functional block diagram which shows a vehicle body controller. It is a figure which shows the processing content of the pump torque control command correction part. It is a figure which shows the operation ratio 1 which is an example of the operation ratio. It is a figure which shows the operation ratio 2 which is an example of the operation ratio. It is a figure which shows the operation ratio 3 which is an example of the operation ratio. It is a figure which shows an example of the relationship between the target fuel consumption reduction coefficient and the degree of fuel consumption reduction, and an example of the relationship of each target fuel consumption reduction coefficient. It is a figure which shows an example of the target fuel consumption reduction coefficient calculation table. It is a flowchart which shows the target fuel consumption reduction coefficient calculation process in the target fuel consumption reduction coefficient calculation part. It is a figure which shows an example of the pump output reduction rate basic value calculation table. It is a figure which shows an example of a pump output reduction rate calculation table. It is a flowchart which shows the setting process of enabling or invalidating a fuel saving mode. It is a figure which shows an example of the change of the horsepower curve such as PQ of a hydraulic pump in a fuel saving mode.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, as an example of the work machine, a hydraulic excavator having a bucket as a work tool at the tip of the front device will be described as an example. However, the present invention will be described as a hydraulic excavator having an attachment other than the bucket such as a breaker or a magnet. It is also possible to apply the invention. It is also possible to apply the present invention to a work machine (including a work machine) other than a hydraulic excavator equipped with a work arm such as a crane car.

FIG. 1 is a side view schematically showing the appearance of a hydraulic excavator which is an example of a work machine according to the present embodiment. Further, FIG. 2 is a diagram schematically showing a main part of the hydraulic circuit system according to the present embodiment, together with a related configuration of the present invention.

In FIG. 1, the hydraulic excavator 100 is an articulated front device 30 configured by connecting a plurality of driven members (boom 31, arm 33, bucket (working tool) 35) that rotate in each vertical direction. The upper swivel body 20 and the lower traveling body 10 constituting the vehicle body are provided, and the upper swivel body 20 is provided so as to be able to swivel with respect to the lower traveling body 10. The upper swivel body 20 is configured by arranging each member on a swivel frame 21 which is a base, and the swivel frame 21 constituting the upper swivel body 20 can swivel with respect to the lower traveling body 10. Further, the base end of the boom 31 of the front device 30 is rotatably supported by the front portion of the upper swing body 20 in a vertical direction, and one end of the arm 33 is an end portion (tip) different from the base end of the boom 31. The bucket 35 is rotatably supported in the vertical direction at the other end of the arm 33.

The boom 31, arm 33, bucket 35, upper swivel body 20, and lower traveling body 10 are the boom cylinder 32, the arm cylinder 34, the bucket cylinder 36, the swivel motor 23, and the left and right traveling motors 11 (however, the left and right traveling motors 11). Only one traveling motor is driven by (shown). On the swivel frame 21 constituting the upper swivel body 20, along with the engine 22 which is a prime mover, each hydraulic actuator 11, 23 such as a boom cylinder 32, an arm cylinder 34, a bucket cylinder 36, a swivel motor 23, and left and right traveling motors 11 , 32, 34, 36 are equipped with a hydraulic circuit system 40 for driving.

In FIG. 2, the hydraulic circuit system 40 is an operation of the engine controller 25 and the engine 22 which are controlled based on a control signal input from the vehicle body controller 49 which controls the entire operation of the hydraulic excavator 100 via the signal path 25a. An engine 22 that operates based on a control signal input from the engine controller 25 that controls the engine to the governor 24 via the signal path 22a, and one or more driven by the engine 22 (in the present embodiment, one case is exemplified). Based on the variable displacement hydraulic pump 41, the fixed capacitance pilot pump 44 driven by the engine 22, and the pilot pressure (control signal) input from the pilot pump 44 via the torque control solenoid valve 45. A control signal (pump torque control command) input from the regulator 46 that controls the tilt angle (discharge flow rate) of the hydraulic pump 41 and the vehicle body controller 49 that controls the operation of the entire hydraulic excavator 100 via the signal path 45a. The torque control solenoid valve 45 that controls the control signal (pilot pressure) input to the regulator 46 and the hydraulic pump 41 driven by the engine 22 supply the hydraulic actuators 11, 23, 32, 34, and 36 based on the above. It is provided with a control valve (flow control valve) 42 that controls the direction and flow rate of the hydraulic oil to be operated. In FIG. 2, the hydraulic actuators 11, 23, 32, 34, and 36 are represented by the flood control actuators 43a and 43b for the sake of simplicity of illustration and description. That is, the hydraulic actuators 43a and 43b correspond to any of the hydraulic actuators 11, 23, 32, 34 and 36.

In the driver's cab (cab) 57 on which the operator is boarded, a plurality of operation lever devices (operation devices) 50 (one in the present embodiment) that output operation signals for operating the hydraulic actuators 23, 32, 34, 36 (one in the present embodiment). (Illustrated on behalf of only) is provided. The control valve 42 is operated by an operation signal (pilot pressure) discharged from a pilot pump 44 driven by the engine 22 and output from an oil passage (not shown) via an operation lever device 50. Although not shown, the plurality of operation lever devices 50 can be tilted back and forth and left and right, respectively, and control valves are based on the pilot pressure (operation signal) according to the operation direction and operation amount of the operation lever device 50 operated by the operator. By controlling 42, the operation of each of the hydraulic actuators 23, 32, 34, 36 is controlled. That is, the operations of the hydraulic actuators 23, 32, 34, and 36 are assigned to the front-rear direction or the left-right direction of the operation lever device 50, respectively. In the signal path of the operation signal output from the operation lever device 50 to the control valve 42, a pressure sensor (operation amount detection device) 53a, which detects the pilot pressure as the operation signal (that is, the operation amount of the operation lever device 50), 53b is provided, and the detection result is input to the vehicle body controller 49 via the signal paths 53f and 53g, respectively.

The operation lever device 50 may be of an electric signal system, and includes a detection device that electrically detects the tilt amount of the lever, that is, the lever operation amount, which is the operation signal of the operation lever device 50 operated by the operator. The lever operation amount detected by the detection device is output to the vehicle body controller 49, which is a control device, via electrical wiring, and the vehicle body controller 49 controls an electromagnetic proportional valve or the like to drive the hydraulic actuators 23, 32, 34, 36. It may be configured to do so.

Further, in the driver's cab (cab) 57, a monitor (display device) for displaying various information about the hydraulic excavator 100, a setting screen, and the like based on a control signal input from the vehicle body controller 49 via the signal path 55a. ) 55 and an operation switch 56 that outputs a control signal for operating various setting screens displayed on the monitor 55 to the vehicle body controller 49 via the signal path 56e are arranged, and the operation lever device 50 has a hydraulic actuator 23. , 32, 34, 36, so that they can be operated in parallel with the operation of the operation lever device 50 (that is, at the same time as the operation of the operation lever device 50). A lever switch 58 (temporary release switch) having a signal path 58a is arranged. The operation switch 56 is for operating various setting screens and the like displayed on the monitor 55. For example, the direction instruction button 56a for moving the position of the instruction display such as the cursor displayed on the monitor 55 in the vertical direction. It includes a 56b, a decision button 56c for determining the selected content, a cancel button 56d for canceling the selected content and returning to the previous process, and the like.

The operation switch 56 is not limited to the above configuration because it is sufficient to operate the contents displayed on the monitor 55. For example, the operation switch 56 is selected or determined by rotating and pressing the rotation switch. The configuration may be adopted.

The vehicle body controller 49 controls the operation of the entire hydraulic excavator 100, and has a PQ iso-horsepower curve (relationship between the discharge pressure of the hydraulic pump 41 and the discharge flow rate) so that the absorption horsepower of the hydraulic pump 41 becomes a predetermined value. The rotation speed of the engine 22 and the discharge flow rate of the hydraulic pump 41 are controlled according to the characteristic line (characteristic line indicating).

FIG. 3 is a functional block diagram showing a vehicle body controller. Further, FIG. 4 is a diagram showing the processing contents of the pump torque control command correction unit.

In FIG. 3, the vehicle body controller 49 includes an operating state determination unit 61, an operating time storage unit 62, a fuel consumption storage unit 63, an input / output control unit 64, a period setting unit 65, an operation ratio calculation unit 66, and a target fuel consumption reduction coefficient calculation. It has a unit 67, a target fuel consumption reduction rate setting unit 68, a pump output reduction rate calculation unit 69, a parameter storage unit 70, a mode setting unit 71, a pump torque control command correction unit 72, and a pump torque command generation unit 73. ..

The operation state determination unit 61 determines the operation state of the hydraulic excavator 100 based on the operation amount of the operation lever device 50 detected by the pressure sensors (operation amount detection devices) 53a and 53b, and determines the determination result as a pump torque control command. Output to the correction unit 72. The operating state of the hydraulic excavator 100 is determined based on the presence or absence of each operation of the operation lever device 50 and the operation amount. That is, more specifically, the operating state of the hydraulic excavator 100 includes work contents such as an idle state, an operation such as excavation by the front device 30 (front operation), a turning operation, and a running operation, and an operation of the operation lever device 50. It is defined by the amount, and in the present embodiment, each operating state is divided into four groups of operating state A, operating state B, operating state C, and other operating states (). See Fig. 4 below). For example, the operating state A is a state in which a running operation is performed (running operation) and a state in which a lever operation for a front operation or a turning operation is performed, and the lever operation amount is equal to or higher than a predetermined lever operation amount large threshold value. A certain operating state (hereinafter referred to as a large amount of front operation lever operation together with the turning operation) is defined. Similarly, the operating state B is a state in which the lever operation of the front operation or the turning operation is performed, the lever operating amount is less than the predetermined lever operating amount large threshold, and the lever operating amount is the predetermined lever. An operation state larger than the operation amount small threshold (hereinafter, referred to as a front operation lever operation amount in combination with the turning operation) is defined, and the operation state C is a state in which the front operation or the turning operation lever operation is performed. Therefore, an operating state in which the lever operating amount is equal to or less than a predetermined lever operating amount small threshold (hereinafter, referred to as a front operating lever operating amount small together with the turning operation) is defined. Further, as other operation states, a running operation, a front operation, an idle state in which the lever operation of the turning operation is not performed, and the like are defined.

The operating time storage unit 62 stores the operating time of each operating state determined by the operating state determining unit 61, and stores the operating state at each time by the clock function (not shown) built in the vehicle body controller 49. Remember. The information on the operating state at each time stored in the operating time storage unit 62 is output to the operating ratio calculation unit 66.

The fuel consumption storage unit 63 stores the fuel consumption of the engine 22 controlled by the engine controller 25, and stores the fuel consumption at each time by the clock function (not shown) built in the vehicle body controller 49. Remember. The fuel consumption information at each time stored in the fuel consumption storage unit 63 is output to the operation ratio calculation unit 66.

The input / output control unit 64 displays various setting screens on the monitor 55, changes the display of the monitor 55 based on the input signals from the operation switch 56 and the lever switch 58, and various types input by the operation switch 56 and the lever switch 58. A GUI (Graphical User) that outputs setting information and controls the presentation of information to the operator and the input from the operator together with the operation switch 56 and the lever switch 58 which are input devices and the monitor 55 which is a display device. Interface) is configured. In the present embodiment, the case where the monitor 55 and the operation switch 56 are separated from each other is illustrated, but these functions may be configured by the touch panel.

The operation ratio calculation unit 66 is set by the period setting unit 65 based on the operation state information at each time from the operating time storage unit 62 and the fuel consumption information at each time from the fuel consumption storage unit 63. Calculates the ratio of the fuel consumption by the engine 22 for each operating state determined by the operating state determination unit 61 in the period (set period), that is, the operating ratio which is the fuel consumption per unit time for each operating state. It is a thing. In the period setting unit 65, a fixed period in the past arbitrarily input by the operator with the operation switch 56 is set as the setting period. If the set period is not set in the period setting unit 65, a period such as the latest one day (24 hours) in the past or the latest one week in the past is set as the set period. The operation ratio calculation unit 66 calculates the operation ratio by integrating the fuel consumption for each operating state for the set period set by the period setting unit 65, and outputs the operation ratio to the target fuel consumption reduction coefficient calculation unit 67. Further, the operation ratio calculated by the operation ratio calculation unit 66 is displayed on the monitor 55 via the input / output control unit 64, and the operator can confirm what kind of operation ratio is calculated according to the set period. it can.

5 to 7 are diagrams showing an example of an operation ratio, FIG. 5 is a diagram illustrating an operation ratio 1, FIG. 6 is a diagram illustrating an operation ratio 2, and FIG. 7 is a diagram illustrating an operation ratio 3.

In FIG. 5, the operation ratio 1 indicates an idle state, a running operation, a large front operation lever operation amount, a medium front operation lever operation amount, and a small front operation lever operation amount in the set period set by the period setting unit 65. It shows the operation ratio with relatively little bias of each operation (state). Further, in FIG. 6, the operation ratio 2 indicates an operation ratio in which the ratio of the fuel consumption in the idle state in the set period is larger than that in the operation ratio 1 and the ratio of the operation in which the front operation lever operation amount is large is small. ing. That is, when the operation ratio such as the operation ratio 2 is shown, it can be said that the work with a relatively light work load is performed such that a small amount of the work with a small load is performed during the set period. Further, in FIG. 7, the operation ratio 3 has a smaller ratio of operations in the front operation lever operation amount during the set period than the operation ratio 2, and a larger operation ratio of the operations with a large front operation lever operation amount. Is shown. That is, when the operation ratio is shown as the operation ratio 3, a large amount of heavy-duty work (work in which the operation state is a large amount of front operation lever operation) such as excavation by front operation and loading by turning operation is performed during the set period. It can be said that this is the case when the work with a relatively heavy workload is performed.

The target fuel consumption reduction coefficient calculation unit 67 uses the target fuel consumption reduction coefficient calculation table empirically set in advance and stored in the parameter storage unit 70 based on the operation ratio calculated by the operation ratio calculation unit 66, and the target fuel consumption reduction coefficient calculation unit 67 is used. Calculate the reduction factor.

FIG. 8A is a diagram showing an example of the relationship between the target fuel consumption reduction coefficient and the degree of fuel consumption reduction and an example of the relationship between each target fuel consumption reduction coefficient, and FIG. 8B is a diagram showing an example of the target fuel consumption reduction coefficient calculation table. Further, FIG. 9 is a flowchart showing a target fuel consumption reduction coefficient calculation process in the target fuel consumption reduction coefficient calculation unit.

As shown in FIG. 8B, the target fuel consumption reduction coefficient calculation table defines the target fuel consumption reduction coefficient for each operating state for each operation ratio. For example, in FIG. 8B, when the operation ratio is 1, the target fuel consumption reduction coefficient for the running operation is A, the target fuel consumption reduction coefficient for the front operation lever operation amount is A, and the operation state is the front. The target fuel consumption reduction coefficient in the operating lever operating amount is B, and the target fuel consumption reduction coefficient in the operating state where the front operating lever operating amount is small is C. Similarly, in FIG. 8B, when the operation ratio is 2, the target fuel consumption reduction coefficient for the running operation is A, the target fuel consumption reduction coefficient for the operating state is A, and the operating state is A. The target fuel consumption reduction coefficient during the front operation lever operation amount is B', and the target fuel consumption reduction coefficient when the operation state is small with the front operation lever operation amount is C'. Further, in FIG. 8B, when the operation ratio is 3, the target fuel consumption reduction coefficient for the running operation is A, the target fuel consumption reduction coefficient for the operating state is A', and the operating state is A'. The target fuel consumption reduction coefficient during the front operation lever operation amount is B', and the target fuel consumption reduction coefficient when the operation state is small with the front operation lever operation amount is C'.

Each target fuel consumption coefficient A, A', B, B', C, C'shown in FIG. 8B has, for example, a relationship as shown in FIG. 8A, that is, A <A'<B <B'<C <C. The relationship of'is set to hold. As will be described later, the final degree of fuel consumption reduction increases as the target fuel consumption coefficient increases. Further, the magnitude of the difference between the fuel consumption reduction degree in the case of the target fuel consumption coefficient A and the fuel consumption reduction degree in the case of the target fuel consumption coefficient A'is ΔA, and the fuel consumption reduction degree and the target fuel consumption coefficient B'in the case of the target fuel consumption coefficient B. If the magnitude of the difference in the degree of fuel consumption reduction is ΔB, and the magnitude of the difference between the degree of fuel consumption reduction in the case of the target fuel consumption coefficient C and the degree of fuel consumption reduction in the case of the target fuel consumption coefficient C'is ΔC, then ΔA <ΔB <ΔC. Each target fuel consumption coefficient A, A', B, B', C, C'is set so that the relationship holds.

For example, in an operating state in which the amount of operation of the front operating lever is large, the effect on the decrease in working speed due to the reduction in fuel consumption is large. Therefore, when the operator considers this, the operator (for example, the operating ratio 1) In contrast to), the operation ratio 2 is output in the operation ratio calculation unit 66 in order to increase the fuel consumption reduction rate (that is, the target fuel consumption reduction coefficient) in the front operation lever operation amount is small or the front operation lever operation amount is small. You can set the setting period like this.

In addition, in the operation ratio 3, the ratio of the idle state and the operation state with a large front operation lever operation amount is large, so that the ratio of the front operation lever operation amount is small and the front operation lever operation amount is small, and the front operation lever is occupied. Since reducing fuel in an operating state with a small amount of operation or an operating amount of the front operating lever may not be sufficient as an effect of reducing fuel consumption, the rate of reduction in fuel consumption even in an operating state with a large amount of operating the front operating lever. (That is, the target fuel consumption reduction coefficient) is increased from the operation ratios 1 and 2. However, as shown in FIG. 8A, in an operating state in which the front operating lever operating amount is large, the reduction in fuel consumption has a large effect on the decrease in working speed. Therefore, the front operating lever operating amount is small and the front operating lever is operated. The fuel consumption reduction rate (that is, the target fuel consumption reduction coefficient) in the operating state where the front operating lever operation amount is large is set smaller than the fuel consumption reduction rate (that is, the target fuel consumption reduction coefficient) in the operating state during the amount.

In addition, the running operation has a large effect on the decrease in working speed due to the reduction in fuel consumption, as in the operating state in which the front operating lever operating amount is large. It is conceivable to set a similar target fuel consumption reduction coefficient.

In FIG. 9, the target fuel consumption reduction coefficient calculation unit 67 first determines whether or not the operation ratio in the idle state is 30% or more of the total operation ratio with respect to the operation ratio calculated by the operation ratio calculation unit 66 (step). S100) If the determination result is YES, it is determined whether or not the operation ratio with a large front operation lever operation amount is 30% or more of the total operation ratio (step S110).

If the determination result in step S110 is YES, it is determined that the operation ratio calculated by the operation ratio calculation unit 66 is the operation ratio 3 closest to the operation ratio 1 to the operation ratio 3, and the target fuel consumption is reduced. The target fuel consumption reduction coefficient corresponding to the operation ratio 3 of the coefficient calculation table is output to the pump output reduction rate calculation unit 69 (step S111). If the determination result in step S110 is NO, it is determined that the operation ratio calculated by the operation ratio calculation unit 66 is closest to the operation ratio 1 to the operation ratio 3, and the target is The target fuel consumption reduction coefficient corresponding to the operation ratio 2 of the fuel consumption reduction coefficient calculation table is output to the pump output reduction rate calculation unit 69 (step S112).

Further, when the determination result in step S100 is NO, that is, when the operation ratio in the idle state of the operation ratio calculated by the operation ratio calculation unit 66 is less than 30% of the total operation ratio, the operation ratio calculation unit. It is determined that the operation ratio calculated in 66 is the operation ratio 1 that is closest to the operation ratio 1 to the operation ratio 3, and the target fuel consumption reduction coefficient corresponding to the operation ratio 1 in the target fuel consumption reduction coefficient calculation table is pumped out. Output to the reduction rate calculation unit 69 (step S101).

The pump output reduction rate calculation unit 69 is a pump output reduction rate basic value calculation table (FIG. 10) that is predetermined and stored in the parameter storage unit 70 based on the target fuel consumption reduction coefficient calculated by the target fuel consumption reduction coefficient calculation unit 67. Refer to), the pump output reduction rate calculation table (see FIG. 11), the lower limit value Z of the fuel consumption reduction rate, and the target fuel consumption reduction rate Y set by the target fuel consumption reduction rate setting unit 68 to determine the pump torque reduction rate. It is calculated and output to the pump torque control command correction unit 72. In the target fuel consumption reduction rate setting unit 68, the target fuel consumption arbitrarily input by the operator with the operation switch 56 is set as the target fuel consumption reduction rate.

FIG. 10 is a diagram showing an example of a pump output reduction rate basic value calculation table. Further, FIG. 11 is a diagram showing an example of a pump output reduction rate calculation table. Note that FIG. 11 illustrates a case where the target fuel consumption reduction coefficient calculation unit 67 calculates the target fuel consumption reduction coefficient of the operation ratio 1 in FIG. 8B.

In the pump output reduction rate calculation unit 69, first, the pump output reduction rate basic value calculation table shown in FIG. 10 is used, and the pump output reduction rate basic value is calculated based on the target fuel consumption reduction coefficient calculated by the target fuel consumption reduction coefficient calculation unit 67. Calculate the value. At this time, the slope X of the pump output reduction rate basic value calculation table becomes the target fuel consumption reduction coefficient-pump output reduction rate basic value ratio X of the pump output reduction rate calculation table of FIG.

Subsequently, the pump output reduction rate calculation unit 69 calculates the pump output reduction coefficient for each operating state as shown in the pump output reduction rate calculation table shown in FIG. 11, and pump output according to the value of the pump output reduction coefficient. Calculate the reduction rate. That is, the pump output reduction coefficient is calculated by multiplying the target fuel consumption reduction coefficient by the target fuel consumption reduction rate divided by the lower limit value of the fuel consumption reduction rate, and when the pump output reduction coefficient is less than 1, the pump output reduction rate is calculated. The pump output reduction rate is calculated by multiplying the target fuel consumption reduction coefficient by the pump output reduction rate basic value ratio, and when the pump output reduction coefficient is 1 or more, the pump output reduction rate is set to 1.

Specifically, the pump output reduction rate is calculated as follows according to each operation state of the running operation, the front operation lever operation amount large, the front operation lever operation amount, and the front operation lever operation amount small illustrated in FIG. To do.
<Operating state: Running operation>
When A × Y ÷ Z <1: A1 = A × Y ÷ Z × X
When A × Y ÷ Z ≧ 1: A1 = 1
<Operating state: Large amount of front operating lever operation>
When A × Y ÷ Z <1: A1 = A × Y ÷ Z × X
When A × Y ÷ Z ≧ 1: A1 = 1
<Operating state: During front operating lever operation amount>
When B × Y ÷ Z <1: B1 = B × Y ÷ Z × X
When B × Y ÷ Z ≧ 1: B1 = 1
<Operating state: Front operating lever operation amount is small>
When C × Y ÷ Z <1: C1 = C × Y ÷ Z × X
When C × Y ÷ Z ≧ 1: C1 = 1
The pump torque control command correction unit 72 determines the pump output reduction rate (A1, B1, C1 in this embodiment) calculated for each operating state by the pump output reduction rate calculation unit 69 and the operating state determination unit 61. Effective operation state (in this embodiment, running operation, front operation lever operation amount is large, front operation lever operation amount is medium, front operation lever operation amount is small), and the fuel saving mode set by the mode setting unit 71 is effective. Alternatively, the pump torque command value output from the pump torque command generation unit 73 to the torque control solenoid valve 45 is corrected based on the invalid setting.

The mode setting unit 71 sets whether to enable or disable the fuel consumption mode input by the operator with the operation switch 56, or to disable the fuel consumption mode input with the lever switch 58 which is a temporary release switch for the fuel consumption mode. Is set as the fuel economy mode state.

FIG. 12 is a flowchart showing a setting process of enabling (ON) or disabling (OFF) of the fuel saving mode.

In FIG. 12, the mode setting unit 71 determines whether or not the operator has input the effective setting of the fuel saving mode by the operation switch 56 with reference to the setting screen (not shown) displayed on the monitor 55 (not shown). In step S200), if the determination result is NO, the fuel saving mode is set to invalid (OFF) and output to the pump torque control command correction unit 72 (step S201). Further, when the determination result in step S200 is YES, that is, when the setting for enabling the fuel saving mode is input, it is determined whether or not the lever switch 58, which is a temporary release switch, has been operated (step S210). If the determination result is NO, the fuel consumption mode is set to valid (ON) and output to the pump torque control command correction unit 72 (step S211). If the determination result in step S210 is YES, that is, When it is determined that the lever switch 58 has been operated, it is determined whether or not a predetermined period (for example, 10 seconds) has elapsed since the lever switch 58 was operated (step S220), and the determination result is NO. In this case, the fuel consumption mode is set to invalid (OFF) until a predetermined time (for example, 10 seconds) elapses from the operation of the lever switch 58 until the determination result becomes YES, and the pump torque control command is issued. Output to the correction unit 72 (step S221). Further, when the determination result in step S220 is YES, that is, when a predetermined time (for example, 10 seconds) has elapsed since the lever switch 58 was operated, the fuel saving mode is set to absorption (ON). Output to the pump torque control command correction unit 72 (step S211).

In FIG. 4, the pump torque control command correction unit 72 has an operating state selection function unit 72a, a fuel consumption mode selection function unit 72b, and a pump output reduction rate integration function unit 72c.

The operation state selection function unit 72a determines which of the plurality of pump output reduction rates calculated by the pump output reduction rate calculation unit 69 for each operation state is used, as a result of the operation state determination unit 61. Select based on. That is, for example, when the determination result of the operation state determination unit 61 is the operation state A, the operation state selection function unit 72a has the pump output reduction rate calculated by the pump output reduction rate calculation unit 69 for the operation state A. Select A1. Similarly, when the determination result of the operation state determination unit 61 is the operation state B, the pump output reduction rate B1 calculated for the operation state B by the pump output reduction rate calculation unit 69 is used by the operation state determination unit 61. When the determination result is the operating state C, the pump output reduction rate calculation unit 69 selects the pump output reduction rate C1 calculated for the operating state C, respectively. When the determination result of the operation state determination unit 61 is another operation state, the pump output reduction rate “1” which is predetermined and stored in the constant storage unit 72d is selected.

The fuel-saving mode selection function unit 72b selects whether or not to enable the pump output reduction rate selected by the operation state selection function unit 72a based on the setting of the mode setting unit 71. That is, for example, when the setting of the mode setting unit 71 is the effective (ON) of the fuel consumption mode, the fuel consumption mode selection function unit 72b selects the pump output reduction rate selected by the operation state selection function unit 72a. When the setting of the mode setting unit 71 is invalid (OFF) of the fuel saving mode, the pump output reduction rate "1" which is predetermined and stored in the constant storage unit 72e is selected.

The pump output reduction rate integration function unit 72c integrates the pump output reduction rate selected by the fuel saving mode selection function unit 72b into the pump torque command value (basic value) generated by the pump torque command generation unit 73. The pump torque command value (correction value) is corrected and output to the torque control electromagnetic valve 45.

The operation and effect of the present embodiment configured as described above will be described.

FIG. 13 is a diagram showing an example of a change in the horsepower curve such as PQ of the hydraulic pump in the fuel saving mode.

In the hydraulic excavator 100 according to the present embodiment, the absorption horsepower of the hydraulic pump 41 is reduced according to the working state by enabling (ON) the fuel saving mode by the operation switch 56 provided in the driver's cab 57. As a result, the mode shifts to the fuel saving mode in which the fuel consumption per unit time (so-called fuel consumption) is suppressed. At this time, as shown in FIG. 13, the product of the pump discharge pressure P of the hydraulic pump 41 and the pump discharge flow rate Q becomes a predetermined constant value smaller than that during normal operation, and the PQ iso-horsepower curve for the fuel saving mode is obtained. Since the hydraulic pump 41 is controlled based on this, the output of the hydraulic actuators 23, 32, 34, and 36 can be suppressed as compared with the normal operation, so that the fuel consumption per unit time can be suppressed.

Further, in the fuel consumption saving mode, the operation ratio, which is the fuel consumption per unit time for each operating state of the hydraulic excavator 100, is calculated, the target fuel consumption reduction coefficient is calculated using this operation ratio, and the target fuel consumption reduction coefficient is used. The pump output reduction rate used for correcting the pump torque command is calculated, and the pump output reduction rate is selected and used according to the operating state of the hydraulic excavator 100. At this time, in the operating state where the working speed is not desired to be reduced as much as possible even in the fuel saving mode (for example, the running operation or the front operation lever operation amount is large), the reduction of the pump output is the minimum necessary even in the fuel saving mode. To suppress the decrease in the maximum working speed of the hydraulic excavator 100 at the work site as much as possible, and reduce the pump output in other working conditions (for example, during the front operating lever operating amount or the front operating lever operating amount is small). Can be. That is, the pump output reduction rate in the fuel-saving mode can be calculated in consideration of the balance between the suppression of fuel consumption and the reduction of the maximum working speed according to the operating state, so that the decrease in working efficiency is suppressed. At the same time, fuel consumption can be suppressed in the fuel saving mode.

Further, since a fixed period in the past arbitrarily input by the operator with the operation switch 56 is set as a set period and the operation ratio is calculated based on this set period, it is closer to the current work content of the hydraulic excavator 100. Since an appropriate operation ratio can be calculated, fuel consumption in the fuel saving mode can be suppressed more accurately.

Further, in the fuel consumption mode, when the operator inputs the invalid setting of the fuel consumption mode with the lever switch 58 which is a temporary release switch of the fuel consumption mode, the fuel consumption mode is set for a predetermined time (for example, 10 seconds). Is disabled, so when the maximum working speed during normal operation is required, the fuel saving mode can be temporarily canceled by operating the lever switch 58, without compromising the convenience of work as much as possible. It is possible to suppress the fuel consumption in the fuel saving mode more accurately while suppressing the decrease in the work efficiency more accurately.

Next, the features of each of the above embodiments will be described.

(1) In the above embodiment, it is driven by a prime mover (for example, engine 22), one or more variable displacement hydraulic pumps 41 driven by the prime mover, and pressure oil discharged from the hydraulic pump. A plurality of hydraulic actuators (for example, a boom cylinder 32, an arm cylinder 34, a bucket cylinder 36, a swivel motor 23, and left and right traveling motors 11), a front device 30 driven by the plurality of hydraulic actuators, and the plurality. Pressure supplied from the hydraulic pump to the plurality of hydraulic actuators based on a plurality of operating devices (for example, an operating lever device 50) for operating each of the actuators and operation signals output from the plurality of operating devices. A flow rate control valve (for example, control valve 42) that controls the flow rate of oil, an operation amount detection device (for example, pressure sensors 53a and 53b) that detects an operation signal output from the operation device, and the hydraulic pump. A vehicle body controller 49 that outputs a pump torque command value for controlling the operation according to a characteristic line showing the relationship between the discharge pressure and the discharge flow rate in the hydraulic pump so that the absorption horsepower of the hydraulic pump becomes a predetermined value is provided. the working machine has, the vehicle body controller, based on the operation signal detected by the operation amount detecting apparatus the operating device, the front determined based on the presence or absence or the operation amount of each operation of said plurality of operating devices Device An operation state determination unit 61 that determines which of a plurality of operation states is, and an operation ratio calculation unit that calculates an operation ratio that is a ratio of fuel consumption for each operation state in a predetermined period. 66, a target fuel pressure reduction coefficient calculation table in which target fuel pressure reduction coefficients corresponding to each of the plurality of operating states are determined for each operation ratio in consideration of the working speed and the degree of fuel pressure reduction, and the operation ratio calculation unit. The target fuel pressure reduction coefficient calculation unit 67 that calculates the target fuel pressure reduction coefficient for each of the plurality of operating states using the calculated operation ratio, and the target hydraulic pump that is input in advance as the target hydraulic pump by the operator of the work machine. Based on the reduction rate, the target fuel consumption reduction coefficient calculated by the target fuel consumption reduction coefficient calculation unit, and the preset ratio of the target fuel consumption reduction coefficient and the pump output reduction rate basic value, the plurality of operating states. the pump output reduction ratio calculation unit 69 for calculating a pump output reduction ratio, among the plurality of pump output reduction rate calculated in the previous SL pump output reduction ratio calculation unit each, the It is assumed to have a pump torque control command correction unit 72 that corrects the pump torque command value based on the pump output reduction rate corresponding to the operation state determined by the operation state determination unit.

As a result, fuel consumption can be suppressed while suppressing a decrease in working speed.

(2) Further, in the above embodiment, in the work machine of (1), a period setting unit 65 for setting a certain period in the past is provided based on the operation of the input device (for example, the operation switch 56) by the operator. In addition, the operation ratio calculation unit 66 of the vehicle body controller 49 calculates the operation ratio based on the period set by the period setting unit.

As a result, a more appropriate operation ratio can be calculated, and fuel consumption in the fuel saving mode can be suppressed more accurately.

(3) Further, in the above embodiment, in the work machine of (1), a temporary release switch (for example, a lever switch 58) that can be operated in parallel with the operation device (for example, the operation lever device 50). The pump torque control command correction unit 72 of the vehicle body controller 49 invalidates the correction of the pump torque command value by the pump torque command correction unit when the temporary release switch is operated.

As a result, it is possible to suppress the fuel consumption in the fuel saving mode more accurately while suppressing the decrease in the work efficiency more accurately without impairing the convenience of the work as much as possible.

<Additional notes>
In the above embodiment, a general hydraulic excavator in which a hydraulic pump is driven by a prime mover such as an engine has been described as an example, but a hybrid type hydraulic excavator in which the hydraulic pump is driven by an engine and a motor, and Needless to say, the present invention can be applied to an electric hydraulic excavator or the like in which a hydraulic pump is driven only by a motor.

Further, the present invention is not limited to the above-described embodiment, and includes various modifications and combinations within a range that does not deviate from the gist thereof. Further, the present invention is not limited to the one including all the configurations described in the above-described embodiment, and includes the one in which a part of the configurations is deleted. Further, each of the above configurations, functions and the like may be realized by designing a part or all of them by, for example, an integrated circuit. Further, each of the above configurations, functions, and the like may be realized by software by the processor interpreting and executing a program that realizes each function.

10 ... Lower traveling body, 11 ... Traveling motor, 11 ... Hydraulic actuator, 20 ... Upper rotating body, 21 ... Swivel frame, 22 ... Engine, 22a, 25a, 45a, 50a, 50b, 53f, 53g, 55a, 56e, 58a ... signal path, 23 ... swivel motor, 24 ... governor, 25 ... engine controller, 30 ... front device, 31 ... boom, 32 ... boom cylinder, 33 ... arm, 34 ... arm cylinder, 35 ... bucket, 36 ... bucket cylinder, 40 ... Hydraulic circuit system, 41 ... Hydraulic pump, 42 ... Control valve (flow control valve), 43a, 43b ... Hydraulic actuator, 44 ... Pilot pump, 45 ... Torque control electromagnetic valve, 46 ... Regulator, 49 ... Body controller, 50 ... operation lever device (operation device), 53a, 53b ... pressure sensor (operation amount detection device), 55 ... monitor (display device), 56 ... operation switch, 56a ... direction indicator button, 56b ... direction indicator button, 56c ... determination Button, 56d ... Cancel button, 57 ... Driver's cab (cab), 58 ... Lever switch (temporary release switch), 61 ... Operating state determination unit, 62 ... Operating time storage unit, 63 ... Fuel consumption storage unit, 64 ... ON Output control unit, 65 ... period setting unit, 66 ... operation ratio calculation unit, 67 ... target fuel consumption reduction coefficient calculation unit, 68 ... target fuel consumption reduction rate setting unit, 69 ... pump output reduction rate calculation unit, 70 ... parameter storage unit, 71 ... Mode setting unit, 72 ... Pump torque control command correction unit, 72a ... Operating state selection function unit, 72b ... Fuel saving mode selection function unit, 72c ... Pump output reduction rate integration function unit, 72d ... Constant storage unit, 72e ... Constant storage unit, 73 ... Pump torque command generator, 100 ... Hydraulic excavator

Claims (3)

The prime mover and
One or more variable displacement hydraulic pumps driven by the prime mover
A plurality of hydraulic actuators driven by the pressure oil discharged from the hydraulic pump, and
The front device driven by the plurality of hydraulic actuators,
A plurality of operating devices for operating the plurality of actuators, and
A flow control valve that controls the flow rate of the pressure oil supplied from the hydraulic pump to the plurality of hydraulic actuators based on the operation signals output from the plurality of operating devices.
An operation amount detection device that detects an operation signal output from the operation device, and an operation amount detection device.
A vehicle body controller that outputs a pump torque command value for controlling the operation of the hydraulic pump according to a characteristic line showing the relationship between the discharge pressure and the discharge flow rate in the hydraulic pump so that the absorption horsepower of the hydraulic pump becomes a predetermined value. In a work machine equipped with
The vehicle body controller
Any of the plurality of operating states of the front device determined based on the presence / absence of each operation of the plurality of operating devices and the operating amount based on the operating signals of the operating device detected by the operating amount detecting device. The operation state determination unit that determines whether or not it is in the operation state of
An operation ratio calculation unit that calculates the operation ratio, which is the ratio of fuel consumption for each operation state in a predetermined period,
The target fuel consumption reduction coefficient corresponding to each of the plurality of operating states was calculated by the target fuel consumption reduction coefficient calculation table and the operation ratio calculation unit, which were determined for each of the operation ratios in consideration of the working speed and the degree of fuel consumption reduction. A target fuel consumption reduction coefficient calculation unit that calculates a target fuel consumption reduction coefficient for each of the plurality of operation states using the operation ratio, and a target fuel consumption reduction coefficient calculation unit.
Wherein the target fuel consumption reduction rate which is previously inputted as the target fuel consumption by a work machine operator, said the target fuel consumption reduction coefficient the target fuel consumption reduction coefficient calculated by the calculating unit, the target fuel consumption reduction factor and the pump output reduction rate set in advance A pump output reduction rate calculation unit that calculates a pump output reduction rate for each of the plurality of operating states based on the ratio to the basic value, and a pump output reduction rate calculation unit.
Before Symbol Of calculated for the plurality of pump output reduction rate at the pump output reduction rate calculating unit, the pump torque command value based on the pump output reduction ratio corresponding to the operation state determined by the operation state judgment unit A work machine characterized by having a pump torque control command correction unit for correcting the above. In the work machine according to claim 1,
It is equipped with a period setting unit that sets a certain period in the past based on the operation of the input device by the operator.
The operation ratio calculation unit of the vehicle body controller is a work machine characterized in that the operation ratio is calculated based on the period set by the period setting unit. In the work machine according to claim 1,
It is equipped with a temporary release switch that can be operated in parallel with the operating device.
The pump torque control command correction unit of the vehicle body controller is a work machine characterized in that the correction of the pump torque command value is invalidated when the temporary release switch is operated.

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