JP5808635B2 - Control method of hybrid excavator - Google Patents

Description

  The present invention relates to a control method for a hybrid excavator including an engine-driven variable displacement pump.

  2. Description of the Related Art Conventionally, a hydraulic excavator that detects fluctuations in engine load based on the transition of turbocharge pressure and executes EGR (exhaust gas recirculation) control based on the detection result is known (see, for example, Patent Document 1). ).

JP 2005-163638 A

  However, the hydraulic excavator described in Patent Document 1 only uses the detection result of engine load fluctuation for EGR control, and uses the detection result to cope with torque shortage when the engine load starts to increase. There is nothing. Therefore, the hydraulic excavator described in Patent Document 1 is a variable displacement pump so that the torque of the variable displacement pump does not exceed the torque of the engine when operating elements such as a boom, an arm, and a bucket are operated and the engine load starts to increase. Must be limited to a certain level or less. This is because a certain time is required until the engine in the no-load state outputs sufficient torque. As a result, the hydraulic excavator described in Patent Document 1 restricts the operation speed at the time of the initial movement of the work element, and makes the operator feel a sense of rattling.

  In view of the above-described points, an object of the present invention is to provide a control method for a hybrid excavator that improves the operability when the work element is initially moved.

  In order to achieve the above-described object, the control method of the hybrid excavator according to the embodiment of the present invention is based on the lever signal and the engine output state, and the normal engine speed control command and the initial operation higher than the normal operation. It is characterized in that it switches between engine speed control commands at the time.

  With the above-described means, the present invention can provide a control method for a hybrid excavator that improves the operability at the time of the initial movement of the work element.

It is a side view of a hybrid type shovel. It is a block diagram which shows the structure of the drive system of the hybrid type shovel by 1st Embodiment. It is a block diagram which shows the structure of an electrical storage system. It is explanatory drawing of the principle of control at the time of initial movement. It is a block diagram (the 1) which shows the structure of the controller which performs control at the time of initial action. It is explanatory drawing of the effect of the initial time control by the controller which has the structure of FIG. It is a block diagram (the 2) which shows the structure of the controller which performs control at the time of initial action. It is explanatory drawing of the effect of the initial action control by the controller which has the structure of FIG. It is a block diagram which shows the structure of the drive system of the hybrid type shovel by 2nd Embodiment.

  FIG. 1 is a side view showing a hybrid excavator to which the present invention is applied.

  An upper swing body 3 is mounted on the lower traveling body 1 of the hybrid excavator via a swing mechanism 2. A boom 4 as a work element is attached to the upper swing body 3. An arm 5 as a work element is attached to the tip of the boom 4, and a bucket 6 as a work element is attached to the tip of the arm 5. The boom 4, the arm 5, and the bucket 6 constitute an attachment, and are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 as hydraulic actuators. The upper swing body 3 is provided with a cabin 10 and is mounted with a power source such as an engine.

  FIG. 2 is a block diagram showing the configuration of the drive system of the hybrid excavator according to the first embodiment of the present invention. In FIG. 2, the mechanical power system is indicated by a double line, the high-pressure hydraulic line is indicated by a solid line (thick line), the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a solid line (thin line).

  An engine 11 as a mechanical drive unit provided with a supercharger and a motor generator 12 as an assist drive unit are connected to two input shafts of a transmission 13, respectively. A main pump 14 as a variable displacement hydraulic pump and a pilot pump 15 as a fixed displacement hydraulic pump are connected to the output shaft of the transmission 13. A control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16.

  The engine 11 is connected to an engine control device 11A. The engine control device 11A includes an engine supercharging pressure sensor that detects an engine supercharging pressure by the supercharger.

  Further, a regulator 14 </ b> A is connected to the main pump 14. The regulator 14A is a device that controls the pump volume of the main pump 14, and is, for example, a swash plate tilt angle control device. Specifically, the regulator 14A includes a discharge pressure interlocking unit 14Aa, a pump proportional valve 14Ab, and a pump proportional valve interlocking unit 14Ac. The discharge pressure interlocking portion 14Aa is a cylinder including a piston interlocking with the discharge pressure of the main pump 14, and the piston is coupled to the swash plate. The discharge pressure interlocking unit 14Aa adjusts the tilt angle of the swash plate so as to reduce the pump volume when the discharge pressure of the main pump 14 increases. The pump proportional valve interlocking portion 14Ac is a cylinder including a piston that interlocks with the output pressure of the pump proportional valve 14Ab, and the piston is coupled to the swash plate. The pump proportional valve interlock 14Ac adjusts the tilt angle of the swash plate so as to reduce the pump volume when the output pressure of the pump proportional valve 14Ab increases. The pump proportional valve 14Ab supplies hydraulic oil having a pressure corresponding to the input current value to the pump proportional valve interlocking unit 14Ac by using the hydraulic oil discharged from the pilot pump 15.

  For example, when none of the work elements is operated, that is, when there is no operation, the regulator 14A suppresses the load on the engine by minimizing the pump volume (tilt angle) and the work element is operated. In addition, the pump volume (tilt angle) is increased so that the required hydraulic fluid is supplied to the hydraulic actuator.

  The control valve 17 is a control device that controls a hydraulic system in the hybrid excavator. The hydraulic motors 1A (for right) and 1B (for left), the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9 and the like for the lower traveling body 1 are connected to the control valve 17 via a high pressure hydraulic line.

  A power storage system (power storage device) 120 including a capacitor as a power storage is connected to the motor generator 12 via an inverter 18. The electric storage system 120 is connected to a turning electric motor 21 as an electric work element via an inverter 20. A resolver 22, a mechanical brake 23, and a turning transmission 24 are connected to the rotating shaft 21 </ b> A of the turning electric motor 21. An operation device 26 is connected to the pilot pump 15 through a pilot line 25. The turning electric motor 21, the inverter 20, the resolver 22, the mechanical brake 23, and the turning transmission 24 constitute a load drive system. Here, the turning electric motor 21 corresponds to a turning electric motor for driving the upper turning body 3 to turn, and the mechanical brake 23 corresponds to a brake device that mechanically brakes the upper turning body 3.

  The operating device 26 includes a lever 26A, a lever 26B, and a pedal 26C. The lever 26A, the lever 26B, and the pedal 26C are connected to the control valve 17 and the pressure sensor 29 via hydraulic lines 27 and 28, respectively. The pressure sensor 29 is connected to a controller 30 that performs drive control of the electric system.

  The discharge pressure sensor 29 </ b> A is a sensor that detects the discharge pressure of the main pump 14, and outputs a detection value to the controller 30.

  FIG. 3 is a block diagram showing the configuration of the power storage system 120. The storage system 120 includes a capacitor 19 as a storage battery, a step-up / down converter, and a DC bus 110. The DC bus 110 serving as the second capacitor controls the power transfer between the capacitor 19 serving as the first capacitor, the motor generator 12, and the turning motor 21. The capacitor 19 is provided with a capacitor voltage detector 112 for detecting a capacitor voltage value and a capacitor current detector 113 for detecting a capacitor current value. The capacitor voltage value and the capacitor current value detected by the capacitor voltage detection unit 112 and the capacitor current detection unit 113 are supplied to the controller 30.

  The step-up / step-down converter 100 performs control for switching between the step-up operation and the step-down operation so that the DC bus voltage value falls within a certain range according to the operating state of the motor generator 12 and the turning electric motor 21. The DC bus 110 is disposed between the inverters 18 and 20 and the step-up / down converter 100, and transfers power between the capacitor 19, the motor generator 12, and the turning electric motor 21.

  Returning to FIG. 2, the controller 30 is a control device as a main control unit that performs drive control of the hybrid excavator. The controller 30 is configured by an arithmetic processing unit including a CPU (Central Processing Unit) and an internal memory, and is realized by the CPU executing a drive control program stored in the internal memory.

  The controller 30 converts the signal supplied from the pressure sensor 29 into a speed command, and performs drive control of the turning electric motor 21. The signal supplied from the pressure sensor 29 corresponds to a signal indicating an operation amount when the operation device 26 is operated to turn the turning mechanism 2.

  The controller 30 performs operation control (switching between electric (assist) operation or power generation operation) of the motor generator 12 and charge / discharge of the capacitor 19 by drivingly controlling the step-up / step-down converter 100 as the step-up / step-down control unit. Take control. The controller 30 is a step-up / down converter based on the charged state of the capacitor 19, the operating state of the motor generator 12 (electric (assist) operation or generating operation), and the operating state of the turning motor 21 (power running operation or regenerative operation). Switching control between 100 step-up operations and step-down operations is performed, and thereby charge / discharge control of the capacitor 19 is performed.

  The switching control between the step-up / step-down operation of the buck-boost converter 100 is performed by controlling the DC bus voltage value detected by the DC bus voltage detection unit 111, the capacitor voltage value detected by the capacitor voltage detection unit 112, and the capacitor current detection unit 113. Is performed based on the capacitor current value detected by. Capacitor 19 may be a chargeable / dischargeable capacitor so that power can be exchanged with DC bus 110 via buck-boost converter 100. FIG. 3 shows a capacitor 19 as a capacitor. Instead of the capacitor 19, a secondary battery capable of charging / discharging such as a lithium ion battery, a lithium ion capacitor, or another form of power source capable of transmitting and receiving power. May be used.

  In the configuration as described above, the electric power generated by the motor generator 12 as an assist motor is supplied to the DC bus 110 of the power storage system 120 via the inverter 18 and supplied to the capacitor 19 via the step-up / down converter 100. . The regenerative power generated by the regenerative operation of the turning electric motor 21 is supplied to the DC bus 110 of the power storage system 120 via the inverter 20 and supplied to the capacitor 19 via the step-up / down converter 100.

  In addition, the controller 30 performs initial motion control that improves operability during initial motion of the attachment.

Here, the principle of the initial operation control will be described with reference to FIG. FIG. 4 shows the pump torque T _{P of} the main pump 14, the pump discharge flow rate Q _P of the main pump 14, and the amount of hydraulic oil Q _C flowing into the bottom side oil chamber of the boom cylinder 7 when the boom 4 is raised. and shows the relationship between the operating speed V _C of the boom 4.

The pump torque _TP of the main pump 14 is the maximum pump volume V _MAX of the main pump 14 and the tilt angle control amount X (the ratio of the current tilt angle to the maximum tilt angle, It becomes.) and is expressed by the product of the discharge pressure P _P of the main pump 14.

The pump discharge flow rate Q _P is the maximum pump volume V _MAX, the tilt angle control amount X, represented by the product of the engine speed N.

Thus, the increase in the engine rotational speed N, increases the pump delivery rate Q _P, does not affect the pump torque T _P of the main pump 14.

Incidentally, the hydraulic oil amount Q _C flowing into the bottom-side oil chamber of the boom cylinder 7, if the other hydraulic actuator is not actuated, proportional to the pump discharge flow rate Q _P. Further, the operating speed V _C of the boom 4 is proportional to the hydraulic oil amount Q _C flowing into the bottom-side oil chamber of the boom cylinder 7. That is, the operating speed V _C of the boom 4 is proportional to the pump discharge flow rate Q _P , and hence the engine speed N.

Such relationships, the controller 30 estimates the pump discharge flow rate Q _P of the main pump 14 based on the hydraulic oil amount Q _C of the boom cylinder 7. The controller 30 may be based on estimated and the pump delivery rate Q _P and the tilt angle control amount X at that time, and calculates the engine speed N required during initial.

From the above relation, the controller 30 may be left with a fixed tilt angle control amount X, to increase the engine rotational speed N, without increasing the pump torque T _P of the main pump 14, the boom 4 thereby increasing the operating speed V _C. This means that even when the engine 11 cannot output a sufficient torque at the time of the initial movement of the boom 4, it is possible to avoid the operation speed of the boom 4 from being limited due to insufficient torque of the engine 11.

  Next, the configuration of the controller 30 that executes the initial operation control will be described with reference to FIG.

  The controller 30 includes an operation determination unit 300 and an engine speed control command generation unit 301 for the initial operation control.

  The operation determination unit 300 is a functional element that outputs a switching signal to the engine speed control command generation unit 301.

  Specifically, the operation determination unit 300 determines whether or not the attachment needs to be actuated based on a lever signal representing the operation state of the operation device 26 output from the pressure sensor 29.

  Further, the operation determination unit 300 determines the load state of the engine 11 based on the engine output state such as the engine load factor and the engine supercharging pressure.

  The engine load factor is calculated as the current engine torque with respect to the rated torque of the engine 11. The pump torque is calculated based on, for example, the discharge pressure of the main pump 14 output from the discharge pressure sensor 29A and the tilt angle output from the regulator 14A, that is, the pump volume. The engine torque is, for example, a value output from the engine control device 11A.

  The engine supercharging pressure is used as an index representing the maximum output of the engine. The maximum output of the engine increases as the engine boost pressure increases. The engine supercharging pressure is a value output by the engine control device 11A, for example.

  When the operation determination unit 300 determines that the engine 11 is in a no-load state and the attachment needs to be operated, the operation determination unit 300 outputs an initial operation switching signal to the engine speed control command generation unit 301. . On the other hand, when the operation determining unit 300 determines that the engine 11 is in a load state or when it is determined that the attachment is not in a necessary state, the operation determining unit 300 performs a normal operation to the engine speed control command generating unit 301. A switching signal is output.

  The engine speed control command generation unit 301 is a functional element that generates an engine speed control command.

  Specifically, the engine speed control command generation unit 301 sets either the initial engine speed or the normal engine speed according to the initial operation switching signal or the normal switching signal from the operation determination unit 300. A corresponding engine speed control command is generated, and the generated engine speed control command is output to the engine control device 11A and the motor generator 12.

  In addition, the engine speed control command generation unit 301, for example, based on the lever signal indicating the operation state of the operating device 26 output from the pressure sensor 29 and the tilt angle output from the regulator 14A, the initial engine speed. To decide.

  Specifically, the engine speed control command generation unit 301 uses, for example, a reference table that determines an engine speed that is stored in advance in the internal memory and that is suitable for the combination of the lever operation angle and the tilt angle of the operation device 26. The engine speed at the time of initial motion suitable for the combination of the lever operating angle and the tilt angle at the present time is determined. Alternatively, the engine speed control command generation unit 301 estimates the pump discharge flow rate of the main pump 14 based on the amount of hydraulic oil flowing into the operation target hydraulic actuator, and the estimated pump discharge flow rate and the tilt angle at that time Based on the above, the initial engine speed may be calculated using Equation 1 (see FIG. 4). The normal engine speed is a constant value stored in advance in the internal memory.

  When the engine speed control command generation unit 301 receives the initial operation switching signal from the operation determination unit 300, the engine speed control command generation unit 301 generates an engine speed control command related to the engine speed at the time of initial operation, and generates the generated engine speed control command. Output to the engine control device 11 </ b> A and the motor generator 12. Alternatively, when the engine speed control command generation unit 301 receives the normal time switching signal, the engine speed control command generation unit 301 generates an engine speed control command related to the normal engine speed, and sends the generated engine speed control command to the engine control device 11A and the engine speed control command. Output to the motor generator 12.

  When the engine control apparatus 11A receives the initial engine speed as an engine speed control command, the engine control apparatus 11A increases the engine speed to the initial engine speed.

  Further, when the motor generator 12 receives the initial engine speed as an engine speed control command, the motor generator 12 assists the engine 11 so that the engine 11 becomes the initial engine speed.

  Next, the effect of the initial control by the controller 30 having the configuration of FIG. 5 will be described with reference to FIG.

  FIG. 6 shows temporal transitions of various physical quantities when executing the initial motion control of the boom 4, FIG. 6 (A) shows the transition of the pump volume, and FIG. 6 (B) shows the transition of the engine speed. 6C shows the transition of the pump discharge flow rate, and FIG. 6D shows the transition of the pump torque. Moreover, the transition represented by the broken line in FIG. 6 shows a transition when the engine speed is not increased during the initial movement of the boom 4 as a comparative example.

  When the boom 4 is raised, the controller 30 determines by the operation determination unit 300 that the engine 11 cannot output the necessary torque. Then, the controller 30 controls the speed of the motor generator 12 so that the engine speed at the initial operation becomes the same. Torque control may be continued until a predetermined rotational speed is reached. Thereby, as shown in FIG. 6B, the controller 30 increases the engine speed from the normal engine speed to the initial engine speed at time t1. As a result, as shown in FIGS. 6 (A) and 6 (D), the controller 30 changes the pump torque and the pump volume as in the case where the engine speed is not increased. In addition, the controller 30 can increase the increase rate of the pump discharge flow rate as shown in FIG. That is, the controller 30 can raise the boom 4 more quickly while keeping the pump torque below the engine torque.

  Thereafter, as shown in FIG. 6C, when the pump discharge flow rate reaches a predetermined value at time t2, the controller 30 gradually reduces the engine speed that is the engine speed at the time of initial operation while gradually reducing the engine speed. Return to the rotation speed. This is because the engine supercharging pressure increases with time and the engine torque also increases. That is, the pump discharge flow rate can be maintained at a predetermined value by increasing the pump volume without increasing the engine speed to the initial engine speed. Note that the predetermined value of the pump discharge flow rate is determined by the operation determination unit 300 based on the operation amount of the operation device 26.

  Thereafter, as shown in FIG. 6B, at the time t3, the engine speed returns to the normal engine speed. This is because the engine speed no longer needs to be larger than the normal engine speed. That is, as shown in FIG. 6C, the pump discharge flow rate reaches a predetermined value at the time t3 even if the engine speed is not increased at the time of the initial movement of the boom 4.

  As described above, the controller 30 temporarily increases the pump discharge flow rate without increasing the pump volume, that is, the pump torque increase pattern as compared with the comparative example, by increasing the engine speed when the boom 4 is initially moved. It is possible to improve the operation speed of the boom 4 when it is initially moved, and thus the operability.

  Note that the effect of the initial movement control shown in FIG. 6 has been described by way of example of the initial movement of the boom 4 raising operation, but is also realized in the initial movement of other work elements. Further, here, the case of the boom alone operation has been described, but the pump discharge flow rate of the main pump 14 during the combined operation of the boom 4 and the arm 5 is based on the amount of hydraulic oil flowing into the boom cylinder 7 and the arm cylinder 8. Is estimated.

  Next, another configuration of the controller 30 that executes the initial operation control will be described with reference to FIG.

  The configuration of FIG. 7 includes the pump proportional valve control command generation unit 302 and the point that the engine speed control command generation unit 301 acquires information about the tilt angle from the pump proportional valve control command generation unit 302 of FIG. Although different from the configuration, the configuration shown in FIG. Therefore, in the following, differences will be described in detail while omitting description of common points.

  The pump proportional valve control command generation unit 302 is a functional element that generates a pump proportional valve control command. The pump proportional valve control command generation unit 302 generates a pump proportional valve control command related to either the initial operation current pattern or the normal operation current pattern according to the initial operation switching signal or the normal operation switching signal from the operation determination unit 300. The generated pump proportional valve control command is output to the pump proportional valve 14Ab.

  Specifically, the pump proportional valve control command generation unit 302 determines whether the main pump 14 is based on the discharge pressure of the main pump 14 output from the discharge pressure sensor 29A and the engine boost pressure output from the engine control device 11A. It is determined whether or not there is no load.

  The pump proportional valve control command generation unit 302 determines that the load on the engine 11 can be reduced by the main pump 14 when the main pump 14 is determined to be in a no-load state, and the load on the engine 11 is reduced. The pump volume (tilt angle) of the main pump 14 required for the above is determined.

  The change in the tilt angle by the discharge pressure interlocking portion 14Aa of the regulator 14A is determined by the discharge pressure of the main pump 14, while the change in the tilt angle by the pump proportional valve interlocking portion 14Ac of the regulator 14A is determined by the pump proportional valve 14Ab. It is determined according to the current pattern supplied to.

  Accordingly, the pump proportional valve control command generation unit 302 generates a pump proportional valve control command related to the initial action current pattern output to the pump proportional valve 14Ab in order to realize the determined pump volume (tilt angle). Note that the initial current pattern and the normal current pattern are both current patterns stored in advance in the internal memory.

  In the above description, an example in which a current pattern at the initial operation is output based on the determined pump volume (tilt angle) is described. However, when the main pump 14 is in a no-load state, the pump volume (tilt angle) is output. Regardless of (), a predetermined initial-time current pattern may be output.

  When the pump proportional valve control command generation unit 302 receives the initial operation switching signal from the operation determination unit 300, the pump proportional valve control command generation unit 302 outputs the pump proportional valve control command related to the initial operation current pattern to the pump proportional valve 14Ab. When the normal time switching signal is received from the determination unit 300, the pump proportional valve control command related to the normal current pattern is output to the pump proportional valve 14Ab.

  When the pump proportional valve 14Ab receives the initial current pattern as a pump proportional valve control command, the pump proportional valve 14Ab supplies hydraulic oil to the pump proportional valve interlocking unit 14Ac so that a desired tilt angle and a desired pump volume is realized. Supply.

  Further, when the pump proportional valve control command generation unit 302 receives the initial operation switching signal from the operation determination unit 300, the pump volume (tilt angle) derived as described above is used as the engine speed control command generation unit 301. When the normal time switching signal is received from the operation determination unit 300, the tilt angle output by the regulator 14A is output to the engine speed control command generation unit 301. The engine speed control command generation unit 301 may directly acquire the tilt angle output by the regulator 14A without going through the pump proportional valve control command generation unit 302.

  In the configuration of FIG. 7, the engine speed control command generation unit 301 outputs a lever signal indicating the operation state of the operating device 26 output by the pressure sensor 29 and the regulator 14 </ b> A every one or a plurality of control cycles. Based on the tilt angle, the engine speed at the initial operation is determined. Alternatively, the engine speed control command generation unit 301 estimates the pump discharge flow rate of the main pump 14 based on the amount of hydraulic oil flowing into the hydraulic actuator to be operated every one or a plurality of control cycles, and the estimated pump discharge Based on the flow rate and the tilt angle at that time, the initial engine speed may be calculated using Equation 1 (see FIG. 4).

  Next, the effect of the initial control by the controller 30 having the configuration of FIG. 7 will be described with reference to FIG.

  FIG. 8 shows temporal transitions of various physical quantities when the initial motion control of the boom 4 is executed as in FIG. In addition, FIG. 8 shows the transition represented by the solid line in FIG. 6 with a dotted line for comparison.

  When the boom 4 is raised, the controller 30 determines by the operation determination unit 300 that the engine 11 cannot output the necessary torque. Then, as shown in FIG. 8 (B), the controller 30 sets the engine speed to the initial engine speed that the engine speed control command generation unit 301 outputs at every one or a plurality of control periods at time t1. Start adjustment. Note that the engine speed at the initial operation in this embodiment is lower than that in the case of the initial operation control by the controller 30 having the configuration of FIG. This is because the torque that the engine 11 can output is judged in more detail while considering the discharge pressure of the main pump 14 and the engine supercharging pressure in more detail, and the pump torque, that is, the pump volume is increased more positively. .

  8A and 8D show that the pump torque and the pump volume are higher than those in the case of the initial operation control by the controller 30 having the configuration of FIG. FIG. 8B shows that the increase in the engine speed is suppressed as compared with the case of the initial operation control by the controller 30 having the configuration of FIG. On the other hand, FIG. 8C shows that the pump discharge flow rate changes in the same manner as in the case of the initial operation control by the controller 30 having the configuration of FIG.

  As described above, the controller 30 having the configuration of FIG. 7 increases the pump volume, that is, the pump torque more positively at the time of the initial movement of the boom 4 than the controller having the configuration of FIG. As a result, it is possible to suppress the increase in the engine speed at the time of the initial movement of the boom 4 while realizing the same transition of the pump discharge flow rate as in the case of the controller having the configuration of FIG. That is, it is possible to improve the fuel efficiency while improving the operation speed of the boom 4 at the time of the initial movement and thus the operability.

  Note that the effect of the initial motion control shown in FIG. 8 has been described by taking the initial motion of the boom 4 raising operation as an example, but the same effect can be realized when the other motion elements are initially operated.

  Next, a second embodiment will be described. FIG. 9 is a block diagram showing the configuration of the drive system of the hybrid excavator according to the second embodiment of the present invention. 9, parts that are the same as the parts shown in FIG. 2 are given the same reference numerals, and descriptions thereof will be omitted.

  As shown in FIG. 9, the hybrid excavator according to the second embodiment is for turning instead of a load drive system including an inverter 20, a turning electric motor 21, a resolver 22, a mechanical brake 23, and a turning transmission 24. Although it is different from the hybrid excavator according to the first embodiment in that it includes the hydraulic motor 21B, it is common in other points.

  Like the hybrid excavator according to the first embodiment, the hybrid excavator according to the second embodiment can be mounted with the controller 30 having any of the configurations shown in FIGS. The controller 30 mounted on the hybrid excavator according to the second embodiment is the same as the turning mechanism 2 in the initial operation of the boom 4, the arm 5, the bucket 6, and the lower traveling body 1 in the hybrid excavator according to the first embodiment. It is possible to improve the operation speed and the operability at the initial movement. Specifically, the pump discharge flow rate is temporarily increased without increasing the pump volume, that is, the pump torque increase pattern, by increasing the engine speed at the initial operation of the swing mechanism 2. The operation speed and thus the operability can be improved.

  DESCRIPTION OF SYMBOLS 1 ... Lower traveling body 1A, 1B ... Hydraulic motor 2 ... Turning mechanism 3 ... Upper turning body 4 ... Boom 5 ... Arm 6 ... Bucket 7 ... Boom cylinder 8 ... arm cylinder 9 ... bucket cylinder 10 ... cabin 11 ... engine 11A ... engine control device 12 ... motor generator 13 ... transmission 14 ... main pump 14A ... Regulator 14Aa ... Discharge pressure interlocking part 14Ab ... Pump proportional valve 14Ac ... Pump proportional valve interlocking part 15 ... Pilot pump 16 ... High pressure hydraulic line 17 ... Control valve 18, 20, -Inverter 19 ... Capacitor 21 ... Electric motor for turning 21B ... Hydraulic motor for turning 22 ... Resolver 23 ... Mechanic Brake 24 ... turning transmission 25 ... pilot line 26 ... operating device 26A, 26B ... lever 26C ... pedal 27 ... hydraulic line 28 ... hydraulic line 29 ... pressure Sensor 29A ... Discharge pressure sensor 30 ... Controller 100 ... Buck-boost converter 110 ... Output terminal DC bus 111 ... DC bus voltage detector 112 ... Capacitor voltage detector 113 ... Capacitor Current detection unit 120 ... Power storage system 300 ... Operation determination unit 301 ... Engine speed control command generation unit 302 ... Pump proportional valve control command generation unit

Claims (5)

A control method of a hybrid excavator equipped with a hydraulic pump that supplies hydraulic oil that operates a working element and an engine that drives the hydraulic pump,
Switching between a normal engine speed control command and an engine speed control command at the time of initial operation higher than normal based on a lever signal indicating an operating state of a lever for operating the work element and an engine output state of the engine The engine speed is temporarily increased from the normal engine speed to the initial engine speed when the work element is initially moved, and then returned to the normal engine speed.
Control method for hybrid excavator. Before determining whether the state operation is required attachment containing the working elements based on crisp bar signal,
To determine the load state of the engine based on the engine output state,
When it is determined that the attachment needs to be operated and the engine is in an unloaded state, the engine speed is temporarily changed from the normal engine speed to the initial engine speed. After increasing, return to the normal engine speed,
The method of controlling a hybrid excavator according to claim 1.   The hybrid excavator control method according to claim 1, wherein the assist motor assists the engine to rotate the engine at the engine speed at the initial operation. Increasing the pump volume of the hydraulic pump according to a pre-stored pattern during the initial movement of the working element;
The control method of the hybrid type shovel in any one of Claims 1-3. The pattern is determined based on the discharge pressure of the hydraulic pump and the engine supercharging pressure.
The method of controlling a hybrid excavator according to claim 4.

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