JP5274978B2 - Hybrid construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid construction machine which can continue an operational state even if assistance from a motor generator cannot be obtained. <P>SOLUTION: The hybrid construction machine includes: a hydraulic pump which is driven by an internal combustion engine; the motor generator which assists the drive of the internal combustion engine for the hydraulic pump; a drive control section which controls the drive of the motor generator, and constitutes a motor generator system together with the motor generator; a capacitor which supplies electric power to the motor generator; a storage control section which controls the charging/discharging of the capacitor, and constitutes a charging/discharging system together with the capacitor; an abnormality detecting section which is provided in the motor generator system or the charging/discharging system, and detects an abnormality in the motor generator system or the charging/discharging system; and a controller which sends a control command to the drive control section and the storage control section. The controller comprises an assist abnormality determination section which determines that the assist abnormality occurs according to a detection value in the abnormality detecting section, and an engine failure prevention section which keeps an upper limit value of an output of the internal combustion engine higher than an output value of the hydraulic pump when the assist abnormality determination section determines that the assist abnormality occurs. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a hybrid construction machine including an electric work element and a hydraulic work element.

  Conventionally, a hybrid construction machine in which a part of a drive mechanism is electrically driven has been proposed. Such a construction machine includes a hydraulic pump for hydraulically driving work elements such as a boom, an arm, and a bucket, and a motor generator is connected to an engine for driving the hydraulic pump via a speed increaser. The motor generator assists the drive of the engine, and the power obtained by the power generation is charged in the capacitor.

In addition to a hydraulic motor as a power source for the turning mechanism for turning the upper turning body, an electric motor is provided in addition to assisting the drive of the hydraulic motor with the electric motor when the turning mechanism is accelerated, and regenerative operation with the electric motor when the turning mechanism is decelerated. The electric power generated is charged in the battery (see, for example, Patent Document 1).
JP-A-10-103112

  By the way, when an abnormality occurs in the motor generator that assists the drive of the hydraulic pump or the inverter that controls the drive of the motor generator, or an abnormality occurs in the battery or the buck-boost converter, the assist cannot be obtained. The output for driving the hydraulic pump may be insufficient.

  In this case, when the motor generator assist cannot be obtained, if the engine output is insufficient with respect to the output of the hydraulic motor, there is a possibility that the operating state cannot be secured.

  Therefore, an object of the present invention is to provide a hybrid construction machine that can continue the operation state even when the motor generator cannot be assisted.

A hybrid construction machine according to one aspect of the present invention includes a hydraulic pump driven by an internal combustion engine, a motor generator that assists the hydraulic pump in driving the internal combustion engine, and drive control of the motor generator. A drive control unit that configures the motor generator and the motor generator system, a capacitor that supplies power to the motor generator, and a power storage control unit that controls charging / discharging of the capacitor and configures a charge / discharge system of the capacitor And an abnormality detection unit that is provided in the motor power generation system and detects an abnormality of the motor power generation system, and a controller that sends a control command to the drive control unit and the power storage control unit, wherein the controller detects the abnormality detection An assist abnormality determination unit that determines an assist abnormality based on a detection value at the unit, and an output upper limit value of the internal combustion engine when the assist abnormality determination unit determines an assist abnormality. And a engine stall prevention portion to maintain a high state than the output value of the pump.

  Further, the engine stall prevention unit may reduce the output value of the hydraulic pump below an output upper limit value of the internal combustion engine.

The pump output control unit may further control the output of the hydraulic pump, and the pump output control unit may control the output of the hydraulic pump by controlling a tilt angle of the hydraulic pump.
The engine stall prevention unit may increase the output upper limit value of the internal combustion engine to be greater than or equal to the output upper limit value of the hydraulic pump.

  The engine speed detector further includes an engine speed detector that detects an engine speed of the internal combustion engine, and the engine stall prevention unit is configured such that the engine speed detected by the engine speed detector is higher than the maximum output generation speed. The output of the internal combustion engine may be increased by reducing the engine speed.

  The engine speed detection unit further detects an engine speed of the internal combustion engine, and the engine stall prevention unit is configured to detect the engine speed detected by the engine speed detection unit when the engine speed is lower than a maximum output generation speed. The output of the internal combustion engine may be increased by increasing the engine speed.

  In addition, a pump output control unit that controls the output of the hydraulic pump may be further included so that the output of the hydraulic pump is less than or equal to the output of the internal combustion engine.

  The required output may be calculated based on an operation amount of an operation unit for operating a work element driven by the hydraulic pressure.

  The output of the hydraulic pump may be calculated based on an operation amount of an operation unit for operating a work element driven by the hydraulic pressure.

  According to the present invention, it is possible to provide a unique effect that it is possible to provide a hybrid construction machine capable of continuing the operation state even when the assist of the motor generator cannot be obtained.

  Embodiments to which the hybrid type construction machine of the present invention is applied will be described below.

[Embodiment 1]
FIG. 1 is a side view showing the hybrid construction machine of the first embodiment.

  An upper turning body 3 is mounted on the lower traveling body 1 of the hybrid construction machine via a turning mechanism 2. In addition to the boom 4, the arm 5, and the bucket 6, and the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 for hydraulically driving them, the upper swing body 3 is equipped with a cabin 10 and a power source. Is done.

"overall structure"
FIG. 2 is a block diagram illustrating the configuration of the hybrid construction machine according to the first embodiment. In FIG. 2, the mechanical power system is indicated by a double line, the high-pressure hydraulic line is indicated by a solid line, the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a solid line.

  An engine 11 as a mechanical drive unit and a motor generator 12 as an assist drive unit are both connected to an input shaft of a speed reducer 13 as a booster. A main pump 14 and a pilot pump 15 are connected to the output shaft of the speed reducer 13. A control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16.

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

  Further, the motor generator 12 is connected to a battery 19 as a capacitor via an inverter 18 and a step-up / down converter 100 as a drive control unit of the motor generator 12. The inverter 18 and the buck-boost converter 100 are connected by a DC bus 110. The motor generator 12 and the inverter 18 constitute a motor generator system, and the battery 19 and the step-up / down converter 100 constitute a charge / discharge system.

  Further, a turning electric motor 21 as an electric work element is connected to the DC bus 110 via an inverter 20. The DC bus 110 is disposed for transferring power between the battery 19, the motor generator 12, and the turning motor 21. The turning electric motor 21, the inverter 20 as a drive control unit of the electric work element, the resolver 22, and the turning speed reducer 24 constitute a load drive system.

  The DC bus 110 is provided with a DC bus voltage detector 111 for detecting a voltage value of the DC bus 110 (hereinafter referred to as a DC bus voltage value). The detected DC bus voltage value is input to the controller 30.

  Further, the battery 19 is provided with a battery voltage detector 112 for detecting the battery voltage value and a battery current detector 113 for detecting the battery current value. The battery voltage value and battery current value detected by these are input to the controller 30.

  A resolver 22, a mechanical brake 23, and a turning speed reducer 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 operating device 26 includes a lever 26A, a lever 26B, and a pedal 26C. The control valve 17 and the pressure sensor 29 are connected to the lever 26A, the lever 26B, and the pedal 26C 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 of the hybrid construction machine of the first embodiment.

  The hybrid construction machine according to the first embodiment is a hybrid construction machine that uses the engine 11, the motor generator 12, and the turning electric motor 21 as power sources. These power sources are mounted on the upper swing body 3 shown in FIG. Hereinafter, each part will be described.

"Configuration of each part"
The engine 11 is an internal combustion engine composed of, for example, a diesel engine, and its output shaft is connected to one input shaft of the speed reducer 13. The engine 11 is controlled by the controller 30 and is always operated while the hybrid construction machine is in operation.

  The motor generator 12 may be an electric motor capable of both electric (assist) operation and power generation operation. Here, a motor generator that is AC driven by an inverter 20 is shown as the motor generator 12. The motor generator 12 can be constituted by, for example, an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in a rotor. The rotating shaft of the motor generator 12 is connected to the other input shaft of the speed reducer 13. The motor generator 12 is provided with a temperature sensor 12A as an abnormality detection unit of the motor generator system. When a load is applied to the motor generator 12, the temperature detection value of the temperature sensor 12A increases. Thereby, if the temperature detection value of the temperature sensor 12A is too high, it can be grasped that the motor generator 12 is in an overload state.

  The speed reducer 13 has two input shafts and one output shaft. A drive shaft of the engine 11 and a drive shaft of the motor generator 12 are connected to each of the two input shafts. Further, the drive shaft of the main pump 14 is connected to the output shaft. When the load on the engine 11 is large, the motor generator 12 performs an electric driving (assist) operation, and the driving force of the motor generator 12 is transmitted to the main pump 14 via the output shaft of the speed reducer 13. Thereby, driving of the engine 11 is assisted. On the other hand, when the load of the engine 11 is small, the driving force of the engine 11 is transmitted to the motor generator 12 through the speed reducer 13, so that the motor generator 12 generates power by the power generation operation. Switching between the power running operation and the power generation operation of the motor generator 12 is performed by the controller 30 according to the load of the engine 11 and the like.

  The main pump 14 is a pump that generates pressure oil to be supplied to the control valve 17, and includes a pump control valve 14A that controls the tilt angle. The pump control valve 14A is electrically driven by the controller 30, and the tilt angle of the main pump 14 is controlled. Pressure oil discharged from the main pump 14 is supplied to drive each of the hydraulic motors 1 </ b> A, 1 </ b> B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 via the control valve 17.

  The pilot pump 15 is a pump that generates a pilot pressure necessary for the hydraulic operation system.

  The control valve 17 receives the hydraulic pressure supplied to each of the hydraulic motors 1A, 1B, the boom cylinder 7, the arm cylinder 8 and the bucket cylinder 9 for the lower traveling body 1 connected via a high pressure hydraulic line. It is a hydraulic control device which controls these hydraulically by controlling according to the above.

  The inverter 18 is provided between the motor generator 12 and the step-up / step-down converter 100 and performs operation control of the motor generator 12 based on a control command from the controller 30. As a result, when the inverter 18 controls the power running of the motor generator 12, necessary power is supplied from the battery 19 and the step-up / down converter 100 to the motor generator 12 via the DC bus 110. Further, when the regeneration control of the motor generator 12 is being controlled, the battery 19 is charged with the electric power generated by the motor generator 12 via the DC bus 110 and the step-up / down converter 100. The inverter 18 is provided with a temperature sensor, a current detector, and a voltage detector (not shown) as an abnormality detection unit of the motor power generation system. In the temperature sensor, the temperature of the switching element of the inverter 18 can be detected, and the current of the motor generator 12 can be detected by the current detector. For example, when a disconnection occurs between the inverter 18 and the motor generator 12, it is possible to detect that an abnormality has occurred by rapidly decreasing the current value detected by the current detector.

  The battery 19 is connected to the inverter 18 and the inverter 20 via the step-up / down converter 100. Thereby, when at least one of the electric (assist) operation of the motor generator 12 and the power running operation of the turning electric motor 21 is performed, electric power necessary for the electric (assist) operation or the power running operation is supplied. In addition, when at least one of the power generation operation of the motor generator 12 and the regenerative operation of the turning motor 21 is performed, the electric power generated by the power generation operation or the regenerative operation is stored as electric energy. Is the power source. The battery 19 is provided with a temperature sensor (not shown) as a charge / discharge abnormality detector. If the overcurrent continues to flow through the battery 19, the temperature detection value of the temperature sensor rises. Therefore, by detecting the temperature detection value of the temperature sensor, it can be determined whether the battery 19 is in an overload state, and charging / discharging System abnormalities can be detected.

  The charge / discharge control of the battery 19 is based on the charge state of the battery 19, the operation state of the motor generator 12 (electric (assist) operation or power generation operation), and the operation state (powering operation or regenerative operation) of the turning motor 21. This is done by the buck-boost converter 100. Switching control between the step-up / step-down operation of the step-up / step-down converter 100 is performed by controlling the DC bus voltage value detected by the DC bus voltage detection unit 111, the battery voltage value detected by the battery voltage detection unit 112, and the battery current detection unit 113. Is performed according to a control command from the controller 30 based on the battery current value detected by the controller 30.

  The inverter 20 is provided between the turning electric motor 21 and the step-up / down converter 100, and performs operation control on the turning electric motor 21 based on a control command from the controller 30. Thereby, when the inverter is operating and controlling the power running of the turning electric motor 21, necessary electric power is supplied from the battery 19 to the turning electric motor 21 through the step-up / down converter 100. Further, when the turning electric motor 21 is performing a regenerative operation, the battery 19 is charged with the electric power generated by the turning electric motor 21 via the step-up / down converter 100. FIG. 2 shows a configuration including a swing motor (1 unit) and an inverter (1 unit). However, by providing a drive unit other than the magnet mechanism and the swing mechanism unit, a plurality of motors and a plurality of inverters are connected to the DC bus. 110 may be connected.

  The buck-boost converter 100 has one side connected to the motor generator 12 and the turning electric motor 21 via the DC bus 110 and the other side connected to the battery 19, so that the DC bus voltage value is within a certain range. Thus, control for switching between step-up and step-down is performed. When the motor generator 12 performs an electric driving (assist) operation, it is necessary to supply electric power to the motor generator 12 via the inverter 18, and thus it is necessary to boost the DC bus voltage value. On the other hand, when the motor generator 12 performs a power generation operation, it is necessary to charge the battery 19 through the inverter 18 with the generated power, and thus it is necessary to step down the DC bus voltage value. The same applies to the power running operation and the regenerative operation of the turning electric motor 21. In addition, the operation state of the motor generator 12 is switched according to the load state of the engine 11, and the turning electric motor 21 is changed to the upper turning body 3. Since the driving state is switched in accordance with the turning operation, the motor generator 12 and the turning motor 21 are either in an electric (assist) operation or a power running operation, and the other is in a power generation operation or a regenerative operation. Can occur.

  For this reason, 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 two inverters 18 and 20 and the step-up / down converter, and is configured to be able to transfer power between the battery 19, the motor generator 12, and the turning electric motor 21. Yes.

  The DC bus voltage detection unit 111 is a voltage detection unit for detecting a DC bus voltage value. The detected DC bus voltage value is input to the controller 30, and is used for switching control between the step-up operation and the step-down operation for keeping the DC bus voltage value within a certain range.

  The battery voltage detection unit 112 is a voltage detection unit for detecting the voltage value of the battery 19 and is used for detecting the state of charge of the battery. The detected battery voltage value is input to the controller 30 and used for switching control between the step-up / step-down operation of the step-up / step-down converter 100. When the disconnection abnormality occurs between converter 100 and battery 19, DC bus voltage detection unit 111 and battery voltage detection unit 112 compare the voltage values of battery voltage detection unit 112 and DC bus voltage detection unit 111. Thus, it also functions as an abnormality detection unit that can identify the occurrence of an abnormality and the location where the abnormality has occurred.

  The battery current detection unit 113 is a current detection unit for detecting the current value of the battery 19. As the battery current value, a current flowing from the battery 19 to the step-up / down converter 100 is detected as a positive value. The detected battery current value is input to the controller 30 and used for switching control between the step-up / step-down operation of the step-up / down converter 100. When a disconnection abnormality occurs between the step-up / down converter 100 and the battery 19, the battery current detection unit 113 detects a sudden decrease in the current value detected by the battery current detection unit 113, thereby Also functions as an abnormality detection unit.

  The turning electric motor 21 may be an electric motor capable of both a power running operation and a regenerative operation, and is an electric work element provided for driving the turning mechanism 2 of the upper turning body 3. During the power running operation, the rotational force of the rotational driving force of the turning electric motor 21 is amplified by the speed reducer 24, and the upper turning body 3 is subjected to acceleration / deceleration control to perform rotational motion. Further, due to the inertial rotation of the upper swing body 3, the number of rotations is increased by the speed reducer 24 and transmitted to the turning electric motor 21, and regenerative power can be generated. Here, as the electric motor 21 for turning, an electric motor driven by an inverter 20 by a PWM (Pulse Width Modulation) control signal is shown. The turning electric motor 21 can be constituted by, for example, a magnet-embedded IPM motor. Thereby, since a larger induced electromotive force can be generated, the electric power generated by the turning electric motor 21 at the time of regeneration can be increased.

  The resolver 22 is a sensor that detects the rotational position and the rotational angle of the rotating shaft 21A of the turning electric motor 21, and is mechanically connected to the turning electric motor 21 to rotate the rotating shaft 21A before the turning electric motor 21 rotates. The rotation angle and the rotation direction of the rotation shaft 21A are detected by detecting the difference between the position and the rotation position after the left rotation or the right rotation. By detecting the rotation angle of the rotation shaft 21A of the turning electric motor 21, the rotation angle and the rotation direction of the turning mechanism 2 are derived. Further, FIG. 2 shows a form in which the resolver 22 is attached, but an inverter control system that does not have an electric motor rotation sensor may be used.

  The mechanical brake 23 is a braking device that generates a mechanical braking force, and mechanically stops the rotating shaft 21 </ b> A of the turning electric motor 21. This mechanical brake 23 is switched between braking and release by an electromagnetic switch. This switching is performed by the controller 30.

  The turning speed reducer 24 is a speed reducer that reduces the rotational speed of the rotating shaft 21 </ b> A of the turning electric motor 21 and mechanically transmits it to the turning mechanism 2. Thereby, in the power running operation, the rotational force of the turning electric motor 21 can be increased and transmitted to the turning body as a larger rotational force. On the contrary, during the regenerative operation, the number of rotations generated in the revolving structure can be increased, and more rotational motion can be generated in the turning electric motor 21.

  The turning mechanism 2 can turn in a state where the mechanical brake 23 of the turning electric motor 21 is released, whereby the upper turning body 3 is turned leftward or rightward.

  The operating device 26 is an operating device for operating the turning electric motor 21, the lower traveling body 1, the boom 4, the arm 5, and the bucket 6. The levers 26A and 26B and the pedal 26C are disposed around the driver's seat in the cabin 10 and are operated by an operator of the hybrid type construction machine.

  The operation device 26 converts the hydraulic pressure (primary hydraulic pressure) supplied through the pilot line 25 into hydraulic pressure (secondary hydraulic pressure) corresponding to the amount of operation of the levers 26A and 26B and the pedal 26C by the operator. Output. The secondary hydraulic pressure output from the operating device 26 is supplied to the control valve 17 through the hydraulic line 27 and detected by the pressure sensor 29.

  The lever 26 </ b> A is a lever for operating the turning electric motor 21 and the arm 5, and the lever 26 </ b> B is a lever for operating the boom 4 and the bucket 6. The pedals 26C are a pair of pedals for operating the lower traveling body 1, and are provided under the feet of the driver's seat.

  When the levers 26A and 26B and the pedal 26C of the operating device 26 are operated, the control valve 17 is driven through the hydraulic line 27, whereby the hydraulic motors 1A and 1B, the boom cylinder 7, the arm cylinder 8 and the bucket cylinder 9 are driven. The lower traveling body 1, the boom 4, the arm 5, and the bucket 6 are driven by controlling the hydraulic pressure inside.

  The hydraulic line 27 supplies hydraulic pressure necessary for driving the hydraulic motors 1A and 1B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder to the control valve.

  The pressure sensor 29 is a sensor as an operation detection unit. When the lever 26A is operated to turn the turning mechanism 2, the pressure sensor 29 detects the operation amount as a change in hydraulic pressure in the hydraulic line 28. To do.

  The pressure sensor 29 outputs an electrical signal indicating the hydraulic pressure in the hydraulic line 28. Thereby, the operation amount of the lever 26A for turning the turning mechanism 2 input to the operating device 26 can be accurately grasped.

  An electric signal representing the operation amount of the turning mechanism 2 and the boom 4 is input to the controller 30 and used for drive control of the turning electric motor 21 and drive control of the boom 4.

  In the first embodiment, a mode in which a pressure sensor as a lever operation detection unit is used will be described. However, an operation amount for turning the turning mechanism 2 input to the lever 26A of the operating device 26 is directly read as an electrical signal. A sensor may be used.

"Controller 30"
The controller 30 is a control device that performs drive control of the hybrid type construction machine of the present embodiment. The controller 30 is composed of an arithmetic processing unit including a CPU (Central Processing Unit) and an internal memory.

  The controller 30 performs operation control of the engine 11, drive control of the motor generator 12, and drive control of the main pump 14. The engine 11 and the motor generator 12 are controlled according to the load of the main pump 14, and the pressure oil generated by the main pump 14 is supplied to the control valve 17.

  Further, the controller 30 applies pressure from the control valve 17 to the hydraulic motors 1A, 1B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 in accordance with operations input to the levers 26A, 26B and the pedal 26C of the operating device 26. The supply amount of oil is controlled and drive control of the lower traveling body 1, the boom 4, the arm 5, and the bucket 6 is performed.

  The controller 30 also includes an assist abnormality determination unit 40. The assist abnormality determination unit 40 includes the temperature of the motor generator 12 detected by the abnormality detection unit, the current value flowing through the motor generator 12, and the motor generator 12. A signal representing a voltage value to be applied, a temperature of a switching element included in the inverter 18, a voltage value supplied to the inverter 18, and a current value supplied to the inverter 18 is input. Similarly, the temperature of the battery 19 detected by the abnormality detection unit, the current value energized to the battery 19 and the buck-boost converter 100, the voltage value applied to the battery 19 and the buck-boost converter 100, and the switching element of the buck-boost converter 100 A signal representing the temperature is input.

  When the detection value detected by the abnormality detection unit is input, the assist abnormality determination unit 40 determines that an assist abnormality has occurred when a threshold value set corresponding to each type of detection value is exceeded.

  In addition, the controller 30 includes an engine stall prevention unit 32. When the engine stall prevention unit 32 determines that an assist abnormality has occurred, the engine malfunction prevention unit 32 performs an engine stall prevention process. In the first embodiment, the engine stall prevention unit 32 controls the pump control valve 14A to prevent engine stall by reducing the tilt angle of the main pump 14 so that the output of the hydraulic pump 14 falls below the engine output upper limit value. Processing is executed.

  Here, the abnormality of the motor generator 12 refers to, for example, a case where a disconnection occurs in the power storage system of the motor generator 12 or the buck-boost converter 100 or the battery 19, or a state where the temperature is abnormally increased.

  Further, the abnormality of the inverter 18 means that the temperature, voltage value, or current value of the switching element exceeds the respective threshold value due to disconnection or failure, and an overheat state, an overvoltage state, or an overcurrent state occurs. Say.

  FIG. 3 is a diagram showing characteristics when the output of the main pump 14 is reduced when an abnormality occurs in the motor generator 12 or the inverter 18 in the hybrid type construction machine of the first embodiment. 11 is a diagram illustrating the output of the main pump 14 and the total output of the engine 11 and the motor generator 12 before and after the abnormality detection. FIG. 5B is a diagram illustrating the main pump when the control command input to the pump control valve 14A changes. It is a figure which shows the relationship between the discharge pressure of 14 and an output. The discharge pressure of the main pump 14 is determined according to the load conditions received by the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, and the hydraulic motors 1A and 1B. Therefore, when the load is light, the output of the main pump 14 is lower than the output upper limit value of the engine 11, and when the load is large, the output is higher than the output upper limit value of the engine 11. Here, when the output of the main pump 14 is higher than the output upper limit value of the engine 11, the motor 11 assists the engine 11.

3A, W _Eng is the output upper limit value of the engine 11, W _Pmpn is the output value of the main pump 14, W _ASM is the output upper limit value of the motor generator 12, and W _Eng + W _ASM is the engine 11 (W _Eng ). And the total output value W _Pmp0 of the motor generator 12 (W _ASM ) represents the output of the main pump 14 after the engine stall prevention process by the engine stall prevention unit 32 of the controller 30 is performed.

At time t = t0, no abnormality has occurred in the motor generator 12 or the inverter 18. At this time, a high output is demanded to the hydraulic cylinder by the operator's lever operation. Accordingly, the output W _Pmpn of the main pump 14 is higher than the output upper limit value W _Eng of the engine 11. For this reason, the controller 30 sends a command to the inverter 18 to assist the engine 11 to the motor generator 12 in order to prevent engine stall. Thereby, even if an output higher than the output upper limit value W _Eng of the engine 11 is requested by the main pump 14, the work can be performed without being stalled. Here, the output upper limit value W _ASM of the motor generator 12 is set to be higher than the output W _Pmpn of the main pump 14 when added to the output upper limit value W _Eng of the engine 11.

However, when the motor generator 12 is overloaded and the detected value by the temperature sensor 12A reaches a predetermined temperature, the assist abnormality determination unit 40 of the controller 30 determines that the motor generator 12 is in an overload state. . In this case, the assist abnormality determination unit 40 of the controller 30 determines that an abnormality has occurred in the motor generator system, and performs motor assist generation to the inverter 18 so as to reduce the load on the motor generator 12 by performing assist abnormality processing. A command is sent to stop the output from the machine 12. Thereby, since the output from the motor generator 12 is lost, the output W _Pmpn of the main pump 14 becomes higher than the output upper limit value W _{Eng of the} engine. Here, in the present embodiment, when an abnormality occurs in the motor generator 12 at time t = t1, the engine stall prevention unit 32 of the controller 30 detects the abnormality of the motor generator 12, and controls the pump control valve 14A. Change the drive command to reduce the tilt angle. As a result, the output of the main pump 14 is _reduced from W _Pmpn to W _Pmp0 that is smaller than the output upper limit value W _{Eng of the} engine 11.

  Here, the drive command for controlling the pump control valve 14A is a pump current I for controlling the tilt angle of the swash plate of the main pump 14.

Therefore, as shown in FIG. 3 (b), the discharge pressure of the main pump 14 in a state of constant at Pi, the pump current I is reduced to _{I 0 (I n> I 0} ) from _{I n,} pump current tilt angle is controlled in accordance with the value, the output of the main pump 14 is reduced from _{W Pmpn} the _{W Pmp0.}

As shown in FIG. 3B, for example, even if the discharge output Pi fluctuates arbitrarily, the current I0 is set so that the output of the main pump 14 does not exceed the output upper limit value W _Eng of the engine 11. Specifically, the current I0 is set so that the maximum value W _Pmpnmax of the output of the main pump 14 does not exceed the output upper limit value W _Eng of the engine 11. For this reason, the main pump 14 can be driven only by the output W _{Eng of the} engine 11 even in a state where there is no assist force by the motor generator 12.

Thus, the output W _Eng of the engine 11 can satisfy the condition of W _Eng > W _Pmp0 even if the output W _Pmpn of the main pump 14 varies depending on the discharge pressure Pi.

As described above, according to the hybrid construction machine of the first embodiment, when an abnormality occurs in the motor generator 12 or the inverter 18, the tilt angle of the main pump 14 is reduced to a predetermined angle by the controller 30. Thus, the output W _Pmp0 of the main pump 14 is controlled to be lower than the output W _{Eng of the} engine 11.

Thus, according to the hybrid type construction machine of the first embodiment, the output of the main pump 14 is reduced even if an abnormality occurs in the motor generator 12 or the inverter 18 and the assist force by the motor generator 12 is lost. Thus, the main pump 14 can be driven only by the output W _Eng of the engine 11, so that the operating state can be continued even when the assist of the motor generator 12 cannot be obtained.

  Further, in the present embodiment, the processing when the temperature abnormality has occurred in the motor generator 12 has been described. However, based on the detection values of the current detector and the voltage detector of the inverter 18 that is the abnormality detection unit of the motor power generation system. Thus, the assist abnormality determination unit 40 may determine abnormality of the motor power generation system. In this case, in addition to this, the engine stall prevention unit 32 may perform processing for reducing the output of the main pump 14.

  Further, even when an abnormality occurs in the charge / discharge system due to a detection value from the abnormality detection unit provided in the charge / discharge system configured by the battery 19 and the step-up / down converter 100, the assist abnormality determination is performed in the same manner as described above. The unit 40 may determine abnormality of the motor power generation system. In this case, since the power supply from the battery 19 to the motor generator 12 becomes impossible, the assist abnormality determination unit 40 determines that the assist is impossible, and performs an assist abnormality determination process for stopping the electric operation and the power generation operation of the motor generator 12. Do. For this reason, even when an abnormality occurs in the charge / discharge system, the engine stall prevention unit 32 may perform the process of reducing the output of the main pump 14 in the same manner as when the abnormality occurs in the motor power generation system.

[Embodiment 2]
FIG. 4 is a diagram showing characteristics when the engine speed of the engine 11 is reduced when an abnormality occurs in the motor generator 12 or the inverter 18 in the hybrid type construction machine of the second embodiment. The figure which plotted the output upper limit value of the engine 11 and the output upper limit value of the main pump 14 with respect to the engine speed, (b) is the output upper limit value of the engine 11, the output of the main pump 14, and the output upper limit value of the motor generator 12. FIG. 3 is a diagram showing a total output upper limit value of an engine 11 and a motor generator 12 before and after abnormality detection.

  The hybrid construction machine according to the second embodiment does not reduce the output of the main pump 14 when an abnormality occurs in the motor generator 12 or the inverter 18, but the output characteristics of the engine 11 and the output characteristics of the main pump 14. The hybrid construction machine according to the first embodiment is different from the hybrid construction machine of the first embodiment in that the engine speed of the engine 11 is set higher than the output of the main pump 14 by adjusting the engine speed of the engine 11 based on the relationship.

  In addition, the output characteristic of the main pump 14 shown to Fig.4 (a) is an output characteristic in case a tilt angle is the maximum. For this reason, in a state where the tilt angle is set smaller than the maximum value, the output characteristic of the main pump 14 takes a lower value than the characteristic shown in FIG.

As shown in FIG. 4A, the output of the main pump 14 has a characteristic that increases approximately linearly as the engine speed increases. On the other hand, the output upper limit value W _Eng of the engine 11 has a characteristic that it increases like a quadratic curve to reach the maximum output as the engine speed increases, and slightly decreases in a region where the engine speed r is high. .

For this reason, as shown in FIG. 4A, when the engine speed is r1, the output W _Pmp1 of the main pump 14 is larger than the output W _{Eng1 of the} engine 11. This state continues until the engine speed increases to r2. That is, the region where the engine speed is equal to or less than r2 is a region where assistance by the motor generator 12 is necessary to drive the hydraulic pump 14.

When the engine speed becomes r2, equals the output _{W Eng1} output _{W PMP1} the engine 11 of the main pump 14, the output upper limit value _{W Eng} of the engine 11, the maximum output _{W Eng3} next when the engine speed r3, then gradually decreased, the engine rotational speed r4, the output _{W Eng1} output _{W PMP1} the engine 11 of the main pump 14 is equal again. That is, when the engine speed is between r2 and r4, the output upper limit value W _Eng of the engine 11 is larger than the output W _Pmp of the main pump 14, so that the hydraulic pump 14 can be operated even without the assist of the motor generator 12. When the engine speed, which can be driven, is higher than r4, the output W _Pmp1 of the main pump 14 becomes larger than the output W _{Eng1 of the} engine 11, as in the area where the engine speed is r2 or less. In order to drive the hydraulic pump 14, assistance by the motor generator 12 is required.

  In the hybrid type construction machine of the second embodiment, when an abnormality occurs in the motor generator 12 or the inverter 18 when the normal engine speed is less than r2, the motor generator 12 or the inverter 18 has an abnormality. The controller 30 controls the engine speed of the engine 11 within a range from r2 to r4.

Thereby, even in the state where the assist of the motor generator 12 is not obtained, the main pump 14 can be driven only by the output upper limit value W _Eng of the engine 11, so that the operation state can be continued.

As shown in FIG. 4B, at time t = 0, the motor generator 12 and the inverter 18 are operating normally, and the engine speed of the engine 11 is r1 when it is normal. At this time, a high output is demanded to the hydraulic cylinder by the operator's lever operation. Here, the output requested to the main pump 14 is requested to be the same value as the output upper limit value W _Pmp1 of the main pump 14 at the rotational speed r1. The output W _Pmp1 to the main pump 14 is an output value higher than the output upper limit value W _Eng of the engine 11. For this reason, the controller 30 sends a command to the inverter 18 to assist the engine 11 to the motor generator 12 in order to prevent the engine 11 from stalling. Thereby, even if the main pump 14 requires a higher output than the output upper limit value W _Eng of the engine 11, the work can be performed without being stalled. Here, the total output upper limit value obtained by adding the output upper limit value W _ASM of the motor generator 12 to the output upper limit value W _Eng of the engine 11 is set to be higher than the output W _Pmp1 of the main pump 14.

However, when the motor generator 12 is overloaded and the detected value by the temperature sensor 12A reaches a predetermined temperature, the assist abnormality determination unit 40 of the controller 30 causes the motor generator 12 to be overloaded. Judge that there is. In this case, the assist abnormality request bottom 40 of the controller 30 determines that an abnormality has occurred in the motor generator system, and performs the assist abnormality process to the inverter 18 so as to reduce the load on the motor generator 12. A command is sent to stop the output from 12. Thereby, since there is no output from the motor generator 12, the output W _Pmp1 of the main pump 14 becomes higher than the output upper limit value W _{Eng1 of the} engine 11. Here, in the present embodiment, when an abnormality occurs in the motor generator 12 at time t = t1, the engine stall prevention unit 32 of the controller 30 detects the abnormality and controls the engine speed of the engine 11 to r3. Here, the output upper / lower value W _Pmp1 of the main pump 14 slightly increases as the rotational speed increases, and becomes W _Pmp3 . At the engine speed r3, the output upper limit value W _Pmp3 of the main pump 14 is the output upper limit value W of the engine 11 even if the main pump 14 is operating at the capability limit value that can be output by the hybrid construction machine of the second embodiment. _It becomes higher than _Eng3 .

Accordingly, the output _{WA ASM} of the motor generator 12 becomes zero due to the occurrence of an abnormality, but the output of the engine 11 becomes W _Eng3 and exceeds the output W _Pmp3 of the main pump 14, so that only the output W _{Eng3 of the} engine 11 The operation of the pump 14 can be continued.

  In the above description, for convenience of explanation, a description has been given of a mode in which the engine speed of the engine 11 is controlled to r3 where the maximum output is generated when an abnormality occurs in the motor generator 12 at time t = t1. The rotation speed is not limited to r3, and may be between r2 and r4. This is because if the engine speed is in the operating range between r2 and r4, the output of the engine 11 exceeds the output of the main pump 14.

As described above, according to the hybrid type construction machine of the second embodiment, when an abnormality occurs in the motor generator 12 or the inverter 18, an operation in which the output of the engine 11 exceeds the output of the main pump 14 by the controller 30. Since it is set in the region, the main pump 14 can be driven only by the output upper limit value W _Eng of the engine 11 even when the assist force by the motor generator 12 is lost, and the operation state can be continued.

  In the above description, the engine speed of the engine 11 is used as the engine speed. However, the speed of the motor generator 12 mechanically coupled to the engine 11 may be used as the engine speed.

[Embodiment 3]
FIG. 5 is a diagram showing characteristics when the engine speed of the engine 11 is reduced when an abnormality occurs in the motor generator 12 or the inverter 18 in the hybrid type construction machine of the third embodiment. The figure which plotted the output upper limit value of the engine 11 and the output upper limit value of the main pump 14 with respect to the engine speed, (b) is the output upper limit value of the engine 11, the output of the main pump 14, and the output upper limit value of the motor generator 12. FIG. 5 is a diagram showing the total output upper limit value of the engine 11 and the motor generator 12 before and after the abnormality detection.

  The output characteristics of the engine 11 and the output characteristics of the main pump 14 shown in FIG. 5A are the same as the characteristics of the second embodiment shown in FIG.

  The hybrid construction machine of Embodiment 3 is operated when the abnormality occurs in the motor generator 12 or the inverter 18 when the normal engine speed is operated at an engine speed r5 higher than r4. 11 is different from the hybrid construction machine of the second embodiment in that the engine speed of 11 is set in the operating range between r2 and r4.

At time t = 0, the motor generator 12 and the inverter 18 are operating normally, and the engine speed of the engine 11 is r5 when normal. At this time, a high output is required for the hydraulic cylinder by the lever operation of the operator. Here, the output requested to the main pump 14 is requested to be the same value as the output upper limit value W _Pmp5 of the main pump 14 at the engine speed r5. The output W _Pmp5 to the main pump 14 is higher than the output upper limit value W _Eng5 of the engine 11. For this reason, the assisting operation by the motor generator 12 is executed. Therefore, the total output upper limit value _obtained by adding the output upper limit value W _ASM of the motor generator 12 and the output upper limit value W _Eng5 of the engine 11 can be set higher than the output W _Pmp5 of the main pump 14.

However, when the motor generator 12 is continuously overloaded and the detection value by the temperature sensor 12A reaches a predetermined temperature, the assist abnormality request bottom 40 of the controller 30 causes the motor generator 12 to be overloaded. Judge that there is. In this case, the assist abnormality request bottom 40 of the controller 30 determines that an abnormality has occurred in the motor generator system, and performs the assist abnormality process to the inverter 18 so as to reduce the load on the motor generator 12. A command is sent from 12 to stop the output. Thereby, since the output of the motor generator 12 is lost, the output W _Pmp5 of the main pump 14 becomes higher than the output upper limit value W _{Eng5 of the} engine 11. Here, in the second embodiment, when an abnormality occurs in the motor generator 12 at time t = t1, the engine stall prevention unit 32 of the controller 30 detects the abnormality and controls the engine speed of the engine 11 to r3.

Here, the output upper limit value _{W PMP5} of the main pump 14 is also reduced to _{W Pmp3} with decreasing rotational speed. In the state where the engine speed is r3, the output upper limit value W _Pmp3 of the main pump 14 is the output of the engine 11 even if the main pump 14 is operating at the capability limit value that can be output by the hybrid type construction machine of the third embodiment. It becomes higher than the upper limit W _Eng3 . Accordingly, the output _{WA ASM} of the motor generator 12 becomes zero due to the occurrence of an abnormality, but the output of the engine 11 becomes W _Eng3 and exceeds the output W _Pmp3 of the main pump 14, so that only the output W _{Eng3 of the} engine 11 The operation of the pump 14 can be continued.

  In the above description, for convenience of explanation, a description has been given of a mode in which the engine speed of the engine 11 is controlled to r3 where the maximum output is generated when an abnormality occurs in the motor generator 12 at time t = t1. The rotation speed is not limited to r3, and may be between r2 and r4. This is because if the engine speed is in the operating range between r2 and r4, the output of the engine 11 exceeds the output of the main pump 14.

As described above, according to the hybrid type construction machine of the third embodiment, when an abnormality occurs in the motor generator 12 or the inverter 18, an operation in which the output of the engine 11 exceeds the output of the main pump 14 by the controller 30. Since it is set in the region, the main pump 14 can be driven only by the output upper limit value W _Eng of the engine 11 even when the assist force by the motor generator 12 is lost, and the operation state can be continued.

  Moreover, although demonstrated using the rotation speed of the engine 11 as an engine speed, you may use the rotation speed of the motor generator 12 mechanically couple | bonded with the engine 11 as an engine speed.

  In the second and third embodiments, the processing when the temperature of the motor generator 12 exceeds the temperature has been described. However, the detection values of the current detector and the voltage detector of the inverter 18 which is an abnormality detection unit of the motor generator system are described. Based on the above, the assist abnormality determination unit 40 may be configured to determine abnormality of the motor power generation system.

  In this case, the engine speed is increased / decreased from the normal rotation speed by the engine stall prevention unit 32 so that the output upper limit value of the engine 11 is driven in a rotation speed region higher than the output upper limit value of the main pump 14. Is done.

  Further, the same applies to the case where an abnormality occurs in the charge / discharge system due to the detection value from the abnormality detection unit provided in the charge / discharge system including the battery 19 and the step-up / down converter 100. In this case, since no power is supplied from the battery 19 to the motor generator 12, the assist abnormality request bottom 40 determines that the assist is impossible, and performs an assist abnormality determination process for stopping the motor operation and the power generation operation of the motor generator 12. . For this reason, even when an abnormality occurs in the charging / discharging system, the engine speed of the engine 11 is higher than the upper limit of the output of the main pump 14 by the engine stall prevention unit 32 in the same manner as when the abnormality occurs in the motor power generation system. The engine speed of the engine 11 is changed so that it can be driven in the region.

  In the first to third embodiments, the hybrid construction machine including the bucket 6 has been described. However, a lifting magnet 200 may be provided instead of the bucket 6. The lifting magnet is an electric working element that attracts or releases metal objects by electromagnetic attraction.

  The hybrid construction machine according to the exemplary embodiment of the present invention has been described above, but the present invention is not limited to the specifically disclosed embodiment and departs from the scope of the claims. Various modifications and changes are possible.

1 is a side view illustrating a hybrid type construction machine according to a first embodiment. 1 is a block diagram illustrating a configuration of a hybrid construction machine according to a first embodiment. It is a figure which shows the characteristic at the time of reducing the output of the main pump 14 when abnormality generate | occur | produces in the motor generator 12 or the inverter 18 in the hybrid type construction machine of Embodiment 1, (a) is the output of the engine 11, The figure which shows the output of the main pump 14, and the total output of the engine 11 and the motor generator 12 before and after abnormality detection, (b) is the discharge pressure of the main pump 14 when the control command input to the pump control valve 14A changes. FIG. FIG. 6 is a diagram illustrating characteristics when the engine speed of the engine 11 is reduced when an abnormality occurs in the motor generator 12 or the inverter 18 in the hybrid construction machine of the second embodiment. FIG. The upper limit value, the output upper limit value of the main pump 14 is plotted against the engine speed, (b) is the output upper limit value of the engine 11, the output of the main pump 14, the output upper limit value of the motor generator 12, the engine 11 and It is a figure which shows the total output upper limit of the motor generator 12 before and after abnormality detection. FIG. 6 is a diagram showing characteristics when the engine speed of the engine 11 is reduced when an abnormality occurs in the motor generator 12 or the inverter 18 in the hybrid type construction machine of the third embodiment. FIG. The upper limit value, the output upper limit value of the main pump 14 is plotted against the engine speed, (b) is the output upper limit value of the engine 11, the output of the main pump 14, the output upper limit value of the motor generator 12, the engine 11 and It is a figure which shows the total output upper limit of the motor generator 12 before and after abnormality detection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower traveling body 1A, 1B Traveling mechanism 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 12 Motor generator 12A Temperature sensor 13 Decelerator 14 Main pump 14A Pump Control valve 15 Pilot pump 16 High pressure hydraulic line 17 Control valve 18 Inverter 19 Battery 20 Inverter 21 Turning electric motor 22 Resolver 23 Mechanical brake 24 Turning reduction gear 25 Pilot line 26 Operating device 26A, 26B Lever 26C Pedal 27 Hydraulic line 28 Hydraulic line 29 Pressure sensor 30 Controller 40 Turning drive control device

Claims (8)

A hydraulic pump which is mechanically connected to the internal combustion engine at all times and is driven by the internal combustion engine ;
A motor generator that assists the hydraulic pump in driving the internal combustion engine;
Drive control of the motor generator, the drive control unit constituting the motor generator and the motor generator system,
A battery for supplying electric power to the motor generator;
A charge control unit for controlling charge / discharge of the capacitor, and constituting a charge / discharge system with the capacitor;
Provided in the electric power generating system, an abnormality detecting unit for detecting an abnormality of said electric power system,
A controller for sending a control command to the drive control unit and the power storage control unit,
The controller includes an assist abnormality determination unit that determines an assist abnormality based on a detection value in the abnormality detection unit, and an output upper limit value of the internal combustion engine that is determined as an assist abnormality by the assist abnormality determination unit. And an engine stall prevention unit that maintains a higher state than the output value.   The hybrid construction machine according to claim 1, wherein the engine stall prevention unit lowers the output value of the hydraulic pump below an output upper limit value of the internal combustion engine. A pump output controller for controlling the output of the hydraulic pump;
The hybrid construction machine according to claim 1 or 2, wherein the pump output control unit controls the output of the hydraulic pump by controlling a tilt angle of the hydraulic pump.   The hybrid construction machine according to claim 1, wherein the engine stall prevention unit increases an output upper limit value of the internal combustion engine to be equal to or higher than an output upper limit value of the hydraulic pump. An engine speed detector for detecting the engine speed of the internal combustion engine;
The engine stop prevention unit increases the output of the internal combustion engine by decreasing the engine speed when the engine speed detected by the engine speed detection unit is higher than a maximum output generation speed. 4. The hybrid type construction machine according to 4. An engine speed detector for detecting the engine speed of the internal combustion engine;
The engine stop prevention unit increases the output of the internal combustion engine by increasing the engine speed when the engine speed detected by the engine speed detection unit is lower than a maximum output generation speed. 4. The hybrid type construction machine according to 4.   The hybrid-type construction machine according to any one of claims 4 to 6, further comprising a pump output control unit that controls an output of the hydraulic pump so that an output of the hydraulic pump is equal to or less than an output of the internal combustion engine. .   The hybrid construction machine according to any one of claims 4 to 7, wherein the output of the hydraulic pump is calculated based on an operation amount of an operation unit for operating a work element driven by the hydraulic pressure.

Images