JP5285655B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle, in particular, a hybrid work vehicle including an engine, a generator motor, and a power storage device, and a deterioration state determination method for a generator motor of the work vehicle.

  In recent years, hybrid vehicles have been developed in the field of work vehicles such as hydraulic excavators. The hybrid work vehicle includes an engine, a generator motor, and a power storage device. The power storage device is, for example, a capacitor or a battery, and stores generated power when the generator motor generates power. The power storage device supplies the electric power stored in the power storage device to a generator motor or an electric motor for driving a work machine.

  When the power storage device is used for a long time or is repeatedly overcharged or overdischarged, the deterioration proceeds. In particular, since the work vehicle is used in a harsh environment, the power storage device mounted on the work vehicle is likely to deteriorate. For this reason, it is necessary to determine the deterioration state of the power storage device in advance and perform maintenance such as replacing the power storage device when the deterioration has progressed to the limit. Here, Patent Document 1 discloses a technique for determining a deterioration state of a power storage device. Here, the capacity of the power storage device is calculated based on the rotation speed and torque of the generator motor, the charging start voltage value and the charging end voltage value of the power storage device, and the charging time. The charging time is the time required for the power storage device to reach the charging end voltage value from the charging start voltage value. Then, the deterioration state of the power storage device is determined by comparing the calculated capacity of the power storage device with the reference capacity.

JP 2009-227044 A

  With the above technique, the deterioration state of the power storage device can be determined. However, not only the power storage device but also the generator motor deteriorates with use. Accordingly, even if only the deterioration state of the power storage device is grasped and the maintenance is appropriately performed, if the generator motor is deteriorated, the time required for charging and discharging becomes long. On the other hand, as a method for determining the deterioration state of the generator motor, it is known to input a predetermined rotation speed and a predetermined torque to the generator motor and measure the rotation speed and torque of the output of the generator motor. However, if such a method is applied to the generator motor mounted on the work vehicle, the generator motor needs to be removed from the work vehicle. In this case, enormous man-hours and costs are required. An object of the present invention is to easily determine a deterioration state of a generator motor in a work vehicle.

  A work vehicle according to a first aspect of the present invention includes an engine, a generator motor, a power storage device, and a deterioration state determination unit. The generator motor has a drive shaft connected to the output shaft of the engine, and performs a power generation operation and an electric operation. The power storage device accumulates electric power when the generator motor performs a power generation operation, and supplies power to the generator motor when the generator motor performs an electric work. The deterioration state determination unit executes at least one of power generation capacity determination and electric power capacity determination in a deterioration state determination control mode for determining the deterioration state of the generator motor. In the power generation capacity determination, the deterioration state determination unit causes the generator motor to perform a power generation operation, and measures the time required for the voltage of the power storage device to rise from the predetermined first voltage value to the second voltage value. In the electric capacity determination, the deterioration state determination unit causes the generator motor to perform electric work, and measures the time required for the voltage of the power storage device to drop from the predetermined third voltage value to the fourth voltage value.

  The work vehicle according to the second aspect of the present invention is the work vehicle according to the first aspect, and further includes a display device that displays information related to the work vehicle. The deterioration state determination unit displays a determination index based on the measured time on the display device.

  A work vehicle according to a third aspect of the present invention is the work vehicle according to the first or second aspect, and further includes an engine control unit and a work mode selection device. The engine control unit controls the engine based on the engine output torque line. The engine output torque line defines the relationship between the engine speed and the upper limit of the engine output torque. The engine control unit controls the engine based on an engine output torque line that is changed according to the selected work mode. The work mode selection device is operated to select a work mode. The deterioration state determination unit executes the deterioration state determination control mode when a specific work mode is selected from the plurality of work modes.

  A work vehicle according to a fourth aspect of the present invention is the work vehicle according to any one of the first to third aspects, and further includes a hydraulic pump, a hydraulic actuator, an operation device, and an operation lock device. The hydraulic pump is driven by the engine. The hydraulic actuator is driven by hydraulic oil discharged from a hydraulic pump. The operating device is a device for operating the hydraulic actuator. The operation lock device is a device for prohibiting the operation of the hydraulic actuator by the operation device. The deterioration state determination unit executes the deterioration state determination control mode when the operation lock device is in a state where the operation of the hydraulic actuator by the operation device is prohibited.

  The work vehicle according to a fifth aspect of the present invention is the work vehicle according to any one of the first to fourth aspects, wherein the first voltage value is at the start of charging the power storage device in the deterioration state determination control mode. Higher than the voltage value.

  A work vehicle according to a sixth aspect of the present invention is the work vehicle according to any one of the first to fifth aspects, wherein the third voltage value is the value at the start of discharging of the power storage device in the deterioration state determination control mode. Lower than the voltage value.

  A work vehicle according to a seventh aspect of the present invention is the work vehicle according to any one of the first to sixth aspects, wherein the deterioration state determination unit is configured to generate power and perform electric power on the generator motor in the deterioration state determination control mode. The operation is continuously performed, and both the power generation capacity determination and the electric power capacity determination are executed.

  The deterioration state determination method for the generator motor of the work vehicle according to the eighth aspect of the present invention is a method for determining the deterioration state of the generator motor in a work vehicle including an engine, a generator motor, and a power storage device. The generator motor has a drive shaft connected to the output shaft of the engine, and performs a power generation operation and an electric operation. The power storage device accumulates electric power when the generator motor performs a power generation operation, and supplies power to the generator motor when the generator motor performs an electric work. In this deterioration state determination method, at least one of power generation capacity determination and electric power capacity determination is executed in a deterioration state determination control mode for determining the deterioration state of the generator motor. In the power generation capacity determination, the time required for the generator motor to generate power and the voltage of the power storage device to rise from the predetermined first voltage value to the second voltage value is measured. In the electric capacity determination, the time required for the voltage of the power storage device to drop from the predetermined third voltage value to the fourth voltage value is measured by causing the generator motor to perform electric work.

  In the work vehicle according to the first aspect of the present invention, at least one of the power generation capacity determination and the power generation capacity determination is performed in a state where the generator motor is mounted on the work vehicle. For this reason, the deterioration state of the generator motor can be determined without removing the generator motor from the work vehicle. Thereby, the deterioration state of a generator motor can be determined easily.

  In the work vehicle according to the second aspect of the present invention, the determination index is displayed on the display device. For this reason, for example, the user can easily determine the deterioration state of the generator motor by comparing the determination index with a predetermined appropriate range described in a service manual or the like.

  In the work vehicle according to the third aspect of the present invention, the input torque to the generator motor or the output torque from the generator motor can be stabilized. Thereby, the deterioration state of the generator motor can be accurately determined.

  In the work vehicle according to the fourth aspect of the present invention, the input torque to the generator motor or the output torque from the generator motor can be stabilized. Thereby, the deterioration state of the generator motor can be accurately determined.

  In the work vehicle according to the fifth aspect of the present invention, the voltage rise time can be measured while the voltage is stable while avoiding the unstable voltage state at the beginning of charging. Thereby, power generation capability determination can be performed accurately.

  In the work vehicle according to the sixth aspect of the present invention, the voltage drop time can be measured while the voltage is stable while avoiding the unstable state of the voltage at the beginning of the discharge. This makes it possible to accurately determine the electric capacity.

  In the work vehicle according to the seventh aspect of the present invention, it is possible to efficiently perform both the power generation capability determination and the electric power capability determination of the generator motor while repeating the charging and discharging of the power storage device.

  In the degradation state determination method for the generator motor of the work vehicle according to the eighth aspect of the present invention, at least one of the power generation capability determination and the motor capability determination is performed in a state where the generator motor is mounted on the work vehicle. For this reason, the deterioration state of the generator motor can be determined without removing the generator motor from the work vehicle. Thereby, the deterioration state of a generator motor can be determined easily.

1 is a perspective view of a work vehicle according to an embodiment of the present invention. The block diagram which shows the structure of the control system of a working vehicle. The figure which shows the output torque line of an engine, and the absorption torque line of a hydraulic pump. The flowchart which shows the process in degradation state determination control mode. The figure which shows an example of the display screen in degradation state determination control mode. The figure which shows an example of the display screen in degradation state determination control mode. The graph which shows the change of the elapsed time at the time of charge and discharge in a degradation state determination control mode, and the voltage of a capacitor. The figure which shows an example of the display screen in degradation state determination control mode.

  A work vehicle 100 according to an embodiment of the present invention is shown in FIG. The work vehicle 100 is a hydraulic excavator and includes a vehicle main body 1 and a work implement 4.

  The vehicle body 1 includes a traveling body 2 and a turning body 3. The traveling body 2 includes a pair of traveling devices 2a and 2b. Each traveling device 2a, 2b has crawler belts 2d, 2e. The traveling devices 2a and 2b cause the work vehicle 100 to travel by driving the crawler belts 2d and 2e by a right traveling motor 37 and a left traveling motor 38 (see FIG. 2) described later.

  The swivel body 3 is placed on the traveling body 2. The revolving structure 3 is provided so as to be able to revolve with respect to the traveling body 2, and revolves when an electric motor 32 (see FIG. 2) described later is driven. The revolving unit 3 is provided with a cab 5. The revolving unit 3 includes a fuel tank 14, a hydraulic oil tank 15, an engine chamber 16, and a counterweight 18. The fuel tank 14 stores fuel for driving an engine 21 (see FIG. 2) described later. The hydraulic oil tank 15 stores hydraulic oil discharged from a hydraulic pump 25 (see FIG. 2) described later. The engine chamber 16 houses devices such as the engine 21 and the hydraulic pump 25 as will be described later. The counterweight 18 is disposed behind the engine chamber 16.

  The work machine 4 is attached to the front center position of the revolving structure 3 and includes a boom 7, an arm 8, a bucket 9, a boom cylinder 10, an arm cylinder 11, and a bucket cylinder 12. A base end portion of the boom 7 is rotatably connected to the swing body 3. Further, the distal end portion of the boom 7 is rotatably connected to the proximal end portion of the arm 8. The tip of the arm 8 is rotatably connected to the bucket 9. The boom cylinder 10, the arm cylinder 11, and the bucket cylinder 12 are hydraulic cylinders that are driven by hydraulic oil discharged from a hydraulic pump 25 described later. The boom cylinder 10 operates the boom 7. The arm cylinder 11 operates the arm 8. The bucket cylinder 12 operates the bucket 9. The work machine 4 is driven by driving these cylinders 10, 11, and 12.

  FIG. 2 shows a configuration diagram of a control system of work vehicle 100. The engine 21 is a diesel engine, and its output horsepower is controlled by adjusting the amount of fuel injected into the cylinder. This adjustment is performed by the electronic governor 23 attached to the fuel injection pump 22 of the engine 21 being controlled by a command signal from the controller 40. As the governor 23, an all-speed control type governor is generally used, and the engine speed and the fuel injection amount are adjusted according to the load so that the engine speed becomes a target speed described later. That is, the governor 23 increases or decreases the fuel injection amount so that there is no deviation between the target engine speed and the actual engine speed. The actual rotational speed of the engine 21 is detected by the rotation sensor 24. The actual rotational speed of the engine 21 detected by the rotation sensor 24 is input to the controller 40 described later as a detection signal.

  A drive shaft of the hydraulic pump 25 is connected to the output shaft of the engine 21. The hydraulic pump 25 is driven by the rotation of the output shaft of the engine 21. The hydraulic pump 25 is a variable displacement hydraulic pump, and its capacity changes as the tilt angle of the swash plate 26 changes.

  The pump control valve 27 operates in response to a command signal input from the controller 40 and controls the hydraulic pump 25 via a servo piston. The pump control valve 27 has a pump absorption torque corresponding to the command value (command current value) of the command signal input from the controller 40 to the pump control valve 27, as the product of the discharge pressure of the hydraulic pump 25 and the capacity of the hydraulic pump 25. The tilt angle of the swash plate 26 is controlled so as not to exceed. That is, the pump control valve 27 controls the absorption torque of the hydraulic pump 25 in accordance with the input command current value.

  The hydraulic oil discharged from the hydraulic pump 25 is supplied to various hydraulic actuators via the operation valve 28. Specifically, the hydraulic oil is supplied to the boom cylinder 10, the arm cylinder 11, the bucket cylinder 12, the right traveling motor 37, and the left traveling motor 38. As a result, the boom cylinder 10, the arm cylinder 11, the bucket cylinder 12, the right traveling motor 37, and the left traveling motor 38 are respectively driven, and the boom 7, the arm 8, the bucket 9, and the crawler belts 2d and 2e of the traveling body 2 are operated. The discharge pressure of the hydraulic pump 25 is detected by the hydraulic sensor 39 and input to the controller 40 as a detection signal.

  The operation valve 28 is a flow direction control valve having a plurality of control valves corresponding to the hydraulic actuators 10-12, 31, 32. The operation valve 28 supplies hydraulic oil to the corresponding hydraulic actuators 10-12, 31, 32 in accordance with the operation direction of the operation devices 51-54. The operation valve 28 moves the spool so that the oil passage is opened by an opening area corresponding to the operation amount of the operation devices 51-54.

  The drive shaft of the generator motor 31 is connected to the output shaft of the engine 21. The generator motor 31 performs a power generation operation and an electric operation. The generator motor 31 is connected to an electric motor 32 and a capacitor 34 as a power storage device via an inverter 33. Electric power is stored in the capacitor 34 by the generator motor 31 generating power. The capacitor 34 supplies power to the electric motor 32. Further, when the generator motor 31 performs an electric action, the capacitor 34 supplies electric power to the generator motor 31. The charging voltage value of the capacitor 34 is detected by the voltage sensor 35. Further, the temperature of the capacitor 34 is detected by the temperature sensor 36. The detection results of the voltage sensor 35 and the temperature sensor 36 are input to the controller 40 as detection signals. The electric motor 32 is driven by being supplied with electric power from the capacitor 34, and turns the revolving structure 3 described above.

  The torque of the generator motor 31 is controlled by the controller 40. When the generator motor 31 is controlled to generate a power, a part of the output torque generated by the engine 10 is transmitted to the drive shaft of the generator motor 31 to absorb the torque of the engine 10 to generate power. AC power generated by the generator motor 31 is converted into DC power by the inverter 33 and supplied to the capacitor 34. When the generator motor 31 is controlled to perform an electric action, the DC power stored in the capacitor 34 is converted into AC power by the inverter 33 and supplied to the generator motor 31. As a result, the drive shaft of the generator motor 31 is rotationally driven, and torque is generated in the generator motor 31. This torque is transmitted from the drive shaft of the generator motor 31 to the output shaft of the engine and added to the output torque of the engine 21. The power generation amount (absorption torque amount) and the motor drive amount (assist amount; generated torque amount) of the generator motor 31 are controlled in accordance with a command signal from the controller 40.

  The inverter 33 converts the electric power generated when the generator motor 31 generates electric power, or the electric power stored in the capacitor 34 into electric power having a desired voltage, frequency, and number of phases suitable for the electric motor 32 to be electric. Supply to the motor 32. In addition, when the turning operation | movement of the turning body 3 is decelerated or braked, the kinetic energy of the turning body 3 is converted into electrical energy. This electric energy is stored in the capacitor 34 as regenerative electric power or supplied as electric power for the electric operation of the generator motor 31.

  In the cab 5, various operation devices 51-56 and a display input device 43 are provided. The various operation devices 51-56 include a first work operation device 51, a second work operation device 52, a first travel operation device 53, a second travel operation device 54, an operation lock device 55, a target rotation speed setting device 56, and the like. Have.

  The first work operation device 51 and the second work operation device 52 are operation devices for operating hydraulic actuators such as the boom cylinder 10, the arm cylinder 11, and the bucket cylinder 12. The first work operation device 51 and the second work operation device 52 each have an operation member such as an operation lever. The operator can operate the work machine 4 by operating the first work operation device 51 and the second work operation device 52.

  The first traveling operation device 53 and the second traveling operation device 54 are operation devices for operating the crawler belts 2d and 2e, respectively. The first travel operation device 53 and the second travel operation device 54 each have an operation member such as an operation lever. The operator can drive the work vehicle 100 by operating the first work operation device 51 and the second work operation device 52.

  When the operation device 51-54 is operated, a pilot pressure (PPC pressure) corresponding to the operation amount of the operation device 51-54 is applied to the pilot port of the operation valve 28 corresponding to each operation device 51-54. . The operation amount and operation direction of the operation devices 51-54 are input to the controller 40 as operation signals. Further, the first work operation device 51 also serves as an operation device for operating the electric motor 32. The controller 40 controls the electric motor 32 based on the operation signal from the first work operation device 51. Thereby, the operator can turn the turning body 3 by operating the first work operation device 51.

  The operation lock device 55 is a device for prohibiting the operation of the hydraulic actuator by the operation devices 51 to 54 described above. The operation lock device 55 has an operation member such as an operation lever. When the operator operates the operation lock device 55 to the lock position, an operation signal (hereinafter referred to as “lock signal”) indicating that the operation lock device 55 has been operated to the lock position is input to the controller 40. A control valve 29 is provided in a hydraulic circuit that connects the above-described operating devices 51-54 and a pilot hydraulic pump (not shown) that supplies hydraulic oil to the operating devices 51-54. The control valve 29 is controlled by a command signal from the controller 40 and is switched between a communication state and a cutoff state. When the control valve 29 is in a communicating state, hydraulic fluid is supplied from the pilot hydraulic pump to the operating devices 51-54. When the control valve 29 is in the shut-off state, the supply of hydraulic oil from the pilot hydraulic pump to the operating devices 51-54 is shut off. That is, the supply of pilot pressure from the operation devices 51-54 to the operation valve 28 is shut off. When the controller 40 receives the lock signal, it sends a command signal to the control valve 29 so as to put the control valve 29 in a shut-off state.

  The target rotational speed setting device 56 is a device for setting a target rotational speed of the engine 21 described later. The target rotation speed setting device 56 has an operation member such as a dial. The operator can manually set the target rotational speed of the engine 21 by operating the target rotational speed setting device 56. The operation content of the target rotation speed setting device 56 is input to the controller 40 as an operation signal.

  The display input device 43 functions as a display device that displays various types of information on the work vehicle 100 such as the engine speed and hydraulic oil temperature. The display input device 43 has a touch panel monitor and functions as an input device operated by an operator. The display input device 43 is operated to instruct execution of a deterioration state determination control mode described later. The display input device 43 also functions as a work mode selection device that is operated to select a work mode of the work machine 4 to be described later.

  The controller 40 is realized by a computer having a memory such as a RAM and a ROM and a device such as a CPU. The controller 40 functions as an engine control unit that controls the engine 21 based on an engine output torque line as indicated by Le1 in FIG. The engine output torque line represents a torque upper limit value that the engine 21 can output according to the rotational speed. In other words, the engine output torque line defines the relationship between the engine speed and the maximum value of the output torque of the engine 21. The engine output torque line is stored in a storage device (not shown). The controller 40 changes the engine output torque line according to the set target rotational speed. The controller 40 sends a command signal to the governor 23 so that the engine speed becomes the set target speed. Note that Le1 in FIG. 3 indicates an engine output torque line when the target rotational speed is the maximum target rotational speed. This engine output torque line corresponds to, for example, the rating of the engine 21 or the maximum power output. The governor 23 controls the output of the engine 21 so that the output torque of the engine 21 does not exceed the engine output torque line.

  Further, the controller 40 calculates a target absorption torque of the hydraulic pump 25 according to the target rotation speed of the engine 21. As shown in FIG. 3, the target absorption torque is set so that the output horsepower of the engine 21 and the absorption horsepower of the hydraulic pump 25 are balanced at the target matching point M1. The controller 40 calculates a target absorption torque based on a pump absorption torque line as indicated by Lp in FIG. The pump absorption torque line defines the relationship between the engine speed and the absorption torque of the hydraulic pump 25, and is stored in the storage device.

  The target matching point is changed according to the work mode of the work machine 4 selected by the display input device 43. As the work mode of the work machine 4, a power mode and an economy mode can be selected. The power mode is a work mode in which high output of the work machine 4 is emphasized. The economy mode is a work mode in which low fuel consumption of the work vehicle 100 is emphasized. The controller 40 changes the engine output torque line so that the matching point is changed according to the selected work mode. Then, the engine 21 is controlled based on the changed engine output torque line. For example, when the maximum target rotational speed is set by the target rotational speed setting device 56 and the power mode is selected, the engine 21 is controlled based on the engine output torque line Le1 of FIG. Thus, the engine 21 and the hydraulic pump 25 are controlled so that the output horsepower of the engine 21 and the absorption horsepower of the hydraulic pump 25 are balanced at the target matching point M1. Further, when the maximum target speed is set by the target speed setting device 56 and the economy mode is selected, the engine 21 is controlled based on the engine output torque line Le2 of FIG. Thus, the engine 21 and the hydraulic pump 25 are controlled so that the output horsepower of the engine 21 and the absorption horsepower of the hydraulic pump 25 are balanced at the target matching point M2.

  The controller 40 functions as a deterioration state determination unit. That is, when the display input device 43 selects execution of the deterioration state determination control mode, the controller 40 executes the deterioration state determination control mode. The deterioration state determination control mode is a control mode for determining the deterioration state of the capacitor 34 and the generator motor 31. The deterioration means that the performance is lowered due to a physical change. Hereinafter, processing in the deterioration state determination control mode will be described based on the flowchart shown in FIG.

  First, in step S1, it is determined whether a measurement condition is satisfied. Here, it is determined whether or not work vehicle 100 is in a state suitable for executing the deterioration state determination control mode. Specifically, it is determined whether measurement conditions such as whether the engine 21 is started, the power mode is selected as the work mode, and whether the operation lock device 55 is in the lock position are satisfied. At this time, as shown in FIG. 5, a screen for prompting the operator to perform an operation so as to satisfy the measurement condition is displayed on the monitor of the display input device 43. When the measurement conditions are satisfied, a screen for confirming the start of measurement is displayed to the operator as shown in FIG.

  In step S2, it is determined whether or not the measurement start switch has been pressed. Here, it is determined whether or not the “START” key on the screen of FIG. 6 has been pressed. When the “START” key is pressed, the process proceeds to step S3.

  In step S3, the power generation operation is started. Here, the controller 40 drives the generator motor 31 at a predetermined rotational speed and a predetermined torque. That is, the controller 40 controls the engine 21 so that the rotation speed and output torque of the engine 21 are constant at predetermined values. Further, the discharge amount of the hydraulic pump 25 is reduced to the minimum. The controller 40 gives a rotational speed command to the engine 21 so as to increase the voltage of the capacitor 34 from a predetermined charging start voltage (V1) to a predetermined charging end voltage (V4). Further, the controller 40 performs constant voltage control on the generator motor 31 so that the capacitor 34 becomes the charging start voltage (V1). As shown in FIG. 7, when the capacitor 34 reaches the charging start voltage (V1), charging of the capacitor 34 is started. Thereafter, the controller 40 controls the generator motor 31 so that the capacitor 34 is charged up to the charging end voltage (V4).

  In step S4, the voltage rise time of the capacitor 34 is measured. Here, the timer is started simultaneously with the start of charging of the capacitor 34. And charging time (DELTA) T1 is measured. The charging time ΔT1 is the time required from the start of charging to the completion of charging. Further, the time Txn required for the voltage of the capacitor 34 to rise from the predetermined first voltage value (V2) to the predetermined second voltage value (V4) is measured. The first voltage value (V2) is higher than the charging start voltage (V1) to the capacitor 34. The second voltage value (V4) is the same value as the charging end voltage (V4).

  When the capacitor 34 is charged to the charge end voltage (V4), the controller 40 stops charging the capacitor 34 in step S5. Further, at the end of charging, the counting of the charging time ΔT1 by the timer ends. Whether the actual charge voltage value of the capacitor 34 has reached the charge start voltage (V1) or the charge end voltage (V4) is determined based on the detection result of the voltage sensor 35.

  As described above, in step S3 to step S5, the power generation capacity determination is executed together with the measurement of the charging time for determining the deterioration of the capacitor 34. That is, the time Txn required for the generator motor 31 to generate power and the voltage of the capacitor 34 to rise from the first voltage value (V2) to the second voltage value (V4) is measured.

  Next, in step S6, the electric action is started. Here, the controller 40 drives the generator motor 31 so as to drive the engine 21 at a predetermined rotational speed and lower the voltage of the capacitor 34 from the discharge start voltage (V4) to the predetermined discharge end voltage (V0). . The discharge start voltage (V4) is the same value as the charge end voltage (V4).

  In step S7, the voltage drop time of the capacitor 34 is measured. Here, the timer is started simultaneously with the start of the discharge of the capacitor 34, and the discharge time ΔT2 is measured. The discharge time ΔT2 is the time required from the start of discharge to the completion of discharge. Further, the time required for the voltage of the capacitor 34 to drop from the predetermined third voltage value (V3) to the predetermined fourth voltage value (V0) is measured. The third voltage value (V3) is a value lower than the discharge start voltage (V4). The fourth voltage value (V0) is the same value as the discharge end voltage (V0).

  When the capacitor 34 is discharged to the discharge end voltage (V0), the controller 40 stops the generator motor 31 and stops discharging the capacitor 34 in step S8. Further, at the end of the discharge, the time measurement of the discharge time ΔT2 by the timer ends. The determination as to whether or not the actual charge voltage value of the capacitor 34 has reached the discharge start voltage V1 and the discharge end voltage V4 is made based on the detection result of the voltage sensor 35.

  As described above, the electric capacity determination is executed from step S6 to step S8. That is, the time required for the voltage of the capacitor 34 to drop from the third voltage value (V3) to the fourth voltage value (V0) is measured by causing the generator motor 31 to perform electric work. Therefore, in the deterioration state determination control mode, the controller 40 causes the generator motor 31 to continuously perform the power generation action and the electric work, and performs both the power generation capacity determination and the electric power capacity determination. The controller 40 captures the temperature of the capacitor 34 detected by the temperature sensor 36 during execution of the deterioration state determination control mode.

  Next, in step S9, it is determined whether or not the measurement has been completed a specified number of times. If the measurement has not been completed a predetermined number of times, the processing from step S3 to step S8 is repeated. If the measurement has been completed a predetermined number of times, the process proceeds to step S10.

  In step S10, a determination index is calculated. Here, a determination index for determining the deterioration state of the capacitor 34 and the generator motor 31 is calculated. The determination index includes a capacitor capacity index, a generator motor power running performance index, and a generator motor regeneration performance index.

The capacitor capacity index is an index based on the capacitor capacity, for example, a value obtained by multiplying the average value of the capacitor capacity by a predetermined constant. The capacitor capacity is calculated based on the rotation value and torque value of the generator motor 31 during execution of the deterioration state determination control mode, the charging start voltage value V1 and the charging end voltage value V4 of the capacitor 34, and the charging time ΔT1. The Specifically, assuming that the energy efficiency when energy is supplied from the generator motor 31 to the inverter 33 is a constant α and the inverter efficiency in the inverter 33 is a constant β, the charging energy ΔJ of the capacitor 34 is the power generation energy of the generator motor 31. Using ΔW, energy efficiency α, inverter efficiency β, and charging time ΔT1, the following equation (1) is used.
ΔJ = ΔW × α− (β × ΔT1) (1)
On the other hand, the charging energy ΔJ of the capacitor 34 is expressed by the following equation (2) using the capacitance C of the capacitor 34, the charging start voltage value V1 and the charging end voltage value V4 of the capacitor 34.
ΔJ = (1/2) · C · (V4−V1) (2)
The capacitance C of the capacitor 34 is calculated from the above equations (1) and (2). And the average capacity | capacitance C is calculated by performing the calculation which averages the capacity | capacitance C of the capacitor 34 calculated from the measurement of prescribed times. A value obtained by multiplying the average capacitance C by a predetermined constant is calculated as the capacitor capacitance index.

  The generator motor power running performance index is the time Txn required for the voltage of the capacitor 34 to rise from the first voltage value (V2) to the second voltage value (V4) (hereinafter referred to as “voltage rise time Txn”). It is an index based on. The generator motor power running performance index is, for example, a value obtained by multiplying the average value of the voltage rise time Txn by a predetermined constant. As the voltage rise time Txn, the value measured in step S4 described above is used (see FIG. 7). The average voltage rise time Tx is calculated by performing an operation of averaging the voltage rise times Txn obtained by the specified number of measurements. Then, a value obtained by multiplying the average voltage rise time Tx by a predetermined constant is calculated as the generator motor power running performance index.

  The generator motor regeneration performance index is the time Tyn required for the voltage of the capacitor 34 to drop from the third voltage value (V3) to the fourth voltage value (V0) (hereinafter referred to as “voltage drop time Tyn”). Index based on. The generator motor regeneration performance index is, for example, a value obtained by multiplying an average value of the voltage drop time Tyn by a predetermined constant. As the voltage drop time Tyn, the value measured in step S7 described above is used (see FIG. 7). The average voltage drop time Ty is calculated by calculating the average of the voltage drop times Tyn obtained by the prescribed number of measurements. A value obtained by multiplying the average voltage drop time Ty by a predetermined constant is calculated as the generator motor regeneration performance index.

  Next, in step S11, the determination index is displayed. Here, as shown in FIG. 8, the capacitor capacity index, the generator motor power running performance index, and the generator motor regeneration performance index are displayed on the monitor of the display input device 43.

  The work vehicle 100 according to the present embodiment has the following features.

  In a state where the generator motor 31 is mounted on the work vehicle 100, the generator motor power running performance index and the generator motor regeneration performance index are calculated and displayed on the monitor of the display input device 43. For this reason, the deterioration state of the generator motor 31 can be determined without removing the generator motor 31 from the work vehicle 100. Thereby, the deterioration state of the generator motor 31 can be determined easily.

  Since the generator motor power running performance index and the generator motor regeneration performance index are displayed on the monitor of the display input device 43, the user can compare the index with a predetermined appropriate range described in the service manual, etc. The deterioration state of the electric motor 31 can be easily determined.

  The degradation state determination control mode can be executed when the power mode is selected as the work mode and when the operation lock device 55 is operated to the lock position. For this reason, the input torque to the generator motor 31 and the output torque from the generator motor 31 can be stabilized. Thereby, the deterioration state of the generator motor 31 can be determined with high accuracy.

  The first voltage value (V2) described above is higher than the charging start voltage value (V1) for the capacitor 34 in the deterioration state determination control mode. For this reason, the voltage rise time can be measured while the voltage is stable while avoiding the unstable state of the voltage at the beginning of charging. Thereby, the generator motor power running performance index can be calculated with high accuracy.

  The above-described third voltage value (V3) is lower than the discharge start voltage value (V4) of the capacitor 34 in the deterioration state determination control mode. For this reason, the voltage drop time can be measured while the voltage is stable while avoiding the unstable state of the voltage at the beginning of the discharge. Thereby, the generator motor regeneration performance index can be calculated with high accuracy.

  In the deterioration state determination control mode, the generator motor 31 is continuously subjected to the power generation action and the electric work, and both the power generation capacity determination and the electric power capacity determination are executed. For this reason, it is possible to efficiently perform both the power generation capacity determination and the power capacity determination of the generator motor 31 while repeating the charging and discharging of the capacitor 34.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

  The present invention is not limited to hydraulic excavators, and may be applied to other types of work vehicles.

  In the deterioration state determination control mode, only one of the power generation capacity determination and the electric power capacity determination may be executed.

  The determination of the deterioration state of the generator motor 31 and the capacitor 34 may be indicated by a display such as “OK” or “NG” instead of an index. For example, a predetermined appropriate range is stored in the storage device, and the determination index calculated by the above method is compared with the appropriate range. Then, “OK” may be displayed when the determination index is within the appropriate range, and “NG” may be displayed when the determination index is outside the appropriate range. Moreover, not only “OK” and “NG”, but other displays indicating a positive determination result and a negative determination result may be displayed.

  The power storage device is not limited to a capacitor, and may be another type of device such as a battery.

  The determination result in the deterioration state determination control mode is not limited to the monitor of the touch panel display input device 43 as described above, and may be displayed on a display-only monitor. Alternatively, the determination result may be displayed with a lamp or the like.

  The controller 40 may be realized by a plurality of computers.

  The present invention has an effect that a deterioration state of a generator motor can be easily determined. Therefore, the present invention is useful as a method for determining a deterioration state of a work vehicle and a generator motor of the work vehicle.

21 Engine 31 Generator motor 34 Capacitor (power storage device)
40 controller (degradation state determination unit, engine control unit)
100 Work vehicle 43 Display input device (display device, work mode selection device)
25 Hydraulic pump 51-54 Operation device 55 Operation lock device

Claims (8)

Engine,
A generator motor having a drive shaft coupled to the output shaft of the engine and performing a power generation action and an electric action;
A power storage device that stores electric power when the generator motor performs a power generation operation, and supplies power to the generator motor when the generator motor performs electric work;
In the deterioration state determination control mode for determining the deterioration state of the generator motor, the generator motor is caused to perform a power generation action, and the voltage of the power storage device rises from a predetermined first voltage value to a second voltage value. Power generation capacity determination that measures the time required for the power generation, and causes the generator motor to perform electric work, and measures the time required for the voltage of the power storage device to drop from the predetermined third voltage value to the fourth voltage value A deterioration state determination unit that performs at least one of electric power determination to be performed,
Work vehicle equipped with. A display device for displaying information on the work vehicle;
The deterioration state determination unit causes the display device to display a determination index based on the measured time.
The work vehicle according to claim 1. The engine is controlled based on an engine output torque line that defines the relationship between the engine speed and the upper limit of the engine output torque, and is based on the engine output torque line that is changed according to the selected work mode. An engine control unit for controlling the engine;
A work mode selection device operated to select the work mode;
Further comprising
The deterioration state determination unit executes the deterioration state determination control mode when a specific work mode is selected from among a plurality of work modes.
The work vehicle according to claim 1 or 2. A hydraulic pump driven by the engine;
A hydraulic actuator driven by hydraulic oil discharged from the hydraulic pump;
An operating device for operating the hydraulic actuator;
An operation locking device for prohibiting the operation of the hydraulic actuator by the operation device;
Further comprising
The deterioration state determination unit executes the deterioration state determination control mode when the operation lock device is in a state in which operation of the hydraulic actuator by the operation device is prohibited.
The work vehicle according to any one of claims 1 to 3. The first voltage value is higher than a voltage value at the start of charging the power storage device in the deterioration state determination control mode.
The work vehicle according to any one of claims 1 to 4. The third voltage value is lower than a voltage value at the start of discharge of the power storage device in the deterioration state determination control mode.
The work vehicle according to any one of claims 1 to 5. The deterioration state determination unit causes the generator motor to continuously perform the power generation action and the electric work in the deterioration state determination control mode, and performs both the power generation capacity determination and the electric power capacity determination.
The work vehicle according to any one of claims 1 to 6. An engine, a drive shaft connected to the output shaft of the engine, and a generator motor that performs a power generation operation and an electric operation; electric power is accumulated by the power generation operation of the generator motor; In a work vehicle comprising a power storage device that supplies power to the generator motor when performing work, a method for determining a deterioration state of the generator motor,
In the deterioration state determination control mode for determining the deterioration state of the generator motor, the generator motor is caused to perform a power generation action, and the voltage of the power storage device rises from a predetermined first voltage value to a second voltage value. Power generation capacity determination that measures the time required for the power generation, and causes the generator motor to perform electric work, and measures the time required for the voltage of the power storage device to drop from the predetermined third voltage value to the fourth voltage value Execute at least one of the electric power determination and
A method for determining a deterioration state of a generator motor of a work vehicle.

Images