JP2015232268A - Hybrid construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid construction machine capable of further improving a fuel consumption rate with respect to the increase/decrease of demand load.SOLUTION: A hybrid construction machine 1 includes: an engine 11; a motor generator 12; a power storage means 120; and a controller 30A controlling the number of revolution of the engine 11 and rotational torque of the motor generator 12. The controller 30A estimates a required load, calculates an engine output based on a revolution speed detection value of the engine 11, and controls the rotational torque of the motor generator 12 so as to generate electric power or assist according to a difference between current output and load while keeping the revolution speed of the engine 11 when a deviation between the revolution speed detection value and a rotational revolution speed target value to load is within a predetermined range. The controller 30A makes the motor generator 12 output the positive (or negative) rotational torque to increase (or reduce) the revolution speed of the engine 11 when the deviation deviates from the predetermined range.

Description

  The present invention relates to a hybrid construction machine.

  Conventionally, a work machine in which a part of a drive mechanism is motorized has been proposed. Such a working machine includes a hydraulic pump for hydraulically driving movable parts such as a boom, an arm, and a bucket, for example, and an AC electric motor (electric motor) is connected to an engine (an internal combustion engine engine) for driving the hydraulic pump. A generator is connected, and an operation for assisting the driving force of the engine and an operation for charging the storage battery with electric power obtained by power generation are performed as necessary.

  In a general hybrid work machine, the engine speed is controlled to be always constant. For example, when the arm or bucket is swung, the load on the engine is small (low load mode), so the motor generator is driven by the surplus torque of the engine while maintaining the engine speed constant. The electric power is stored in the capacitor. When the engine load exceeds the engine output at the rotation speed (high load mode), the motor generator is driven by the electric power from the capacitor while maintaining the engine rotation speed constant. Add the output of the motor generator to the output.

  In addition, the construction machine described in Patent Document 1 is in a low load mode (in a mode in which the intersection point between the equal horsepower line and the governor characteristic line of the required horsepower of the engine is an engine torque smaller than the rated output of the engine). The engine torque is increased to improve the fuel consumption rate, and the generator is driven by the surplus torque to charge the capacitor.

Japanese Patent Laid-Open No. 2004-1000062

  However, if the engine speed is controlled to be always constant, the following problem occurs. In many cases, the rotational speed is set to a value at which fuel consumption is lowest for a certain medium load. If the load increases while maintaining the rotational speed, the engine output that is insufficient can be assisted by the motor generator. However, if such a high load continues, there may be cases where it cannot be assisted depending on the charge amount of the capacitor. In this case, a larger engine torque is required and the fuel consumption rate is increased.

  On the other hand, if the load is reduced while maintaining the rotation speed, the surplus engine output can be used to generate power in the motor generator. However, if such a low load continues, the charging capacity of the capacitor is limited. There are cases where power generation is not possible. In this case, although the engine torque is smaller, the number of rotations is maintained and the fuel consumption rate is prevented from being improved.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a hybrid construction machine that can further improve the fuel consumption rate with respect to increase or decrease in required load.

  In order to solve the above-described problem, a first hybrid construction machine according to the present invention is connected to an internal combustion engine engine, a speed detection unit that detects a rotation speed of the internal combustion engine engine, and the internal combustion engine engine. A motor generator that generates electric power by the driving force of the internal combustion engine motor, assists the driving force of the internal combustion engine motor by its own driving force, a storage battery that is electrically connected to the motor generator, and an internal combustion engine motor A control unit that controls the rotational speed and the rotational torque of the motor generator, the control unit calculates a load of the internal combustion engine motor required in the hybrid type construction machine, and detects a rotational speed detection value and an internal combustion engine When the deviation from the rotational speed target value corresponding to the load of the engine is within a predetermined range, the power generation by the driving force of the internal combustion engine or the internal combustion engine motor while maintaining the rotational speed of the internal combustion engine Driving The rotational torque of the motor generator is controlled to assist the motor, and when the deviation exceeds a predetermined range, a positive rotational torque is output from the motor generator based on the target rotational speed of the internal combustion engine engine. When the deviation falls below a predetermined range, a negative rotational torque is output from the motor generator based on the target rotational speed of the internal combustion engine engine.

  A second hybrid construction machine according to the present invention includes an internal combustion engine engine, a speed detection unit that detects a rotational speed of the internal combustion engine engine, and a driving force of the internal combustion engine engine that is connected to the internal combustion engine engine. A motor generator that generates electric power and assists the driving force of the internal combustion engine motor by its own driving force, a storage battery that is electrically connected to the motor generator, the rotational speed of the internal combustion engine motor, and the motor generator A control unit that controls the rotational torque of the internal combustion engine. The control unit calculates a load of the internal combustion engine motor required in the hybrid type construction machine, and a required torque calculated from the load of the internal combustion engine motor is predetermined. Of the motor generator so as to generate power by the driving force of the internal combustion engine motor or assist the driving force of the internal combustion engine motor while maintaining the rotational speed of the internal combustion engine motor. When the required torque exceeds a predetermined torque range, a positive rotational torque is output from the motor generator based on the target rotational speed of the internal combustion engine and the required torque falls within the predetermined torque range. When it falls below, a negative rotational torque is output from a motor generator based on the target rotational speed of the internal combustion engine engine.

  In the first and second hybrid construction machines, the control unit includes a switch unit that switches the motor generator from control of the rotational torque to control based on the target rotational speed of the internal combustion engine engine. It is good. In this case, the control unit includes a load determination unit that determines the load of the internal combustion engine motor, and a command value calculation unit that generates a target rotational speed of the internal combustion engine motor based on the load determination result by the load determination unit. It is preferable.

  The first and second hybrid construction machines may be characterized in that the command value calculation unit of the control unit further generates a pump horsepower setting signal based on the load determination result.

  A third hybrid type construction machine according to the present invention includes an internal combustion engine engine, a speed detection unit that detects the rotational speed of the internal combustion engine engine, and a driving force of the internal combustion engine engine that is connected to the internal combustion engine engine. A motor generator that generates electric power and assists the driving force of the internal combustion engine motor by its own driving force, a storage battery that is electrically connected to the motor generator, the rotational speed of the internal combustion engine motor, and the motor generator A control unit for controlling the rotational torque of the engine, and the control unit estimates a load required in the hybrid type construction machine and is based on a detected rotational speed value of the internal combustion engine motor provided from the speed detecting unit. If the required torque calculated from the load is within a predetermined torque range corresponding to the detected rotational speed, the rotational speed of the internal combustion engine is maintained. According to the difference between the current output and the load, the rotational torque of the motor generator is controlled so as to generate electric power by the driving force of the internal combustion engine engine or to assist the driving force of the internal combustion engine motor, and the required torque is predetermined. When the torque range is exceeded, a positive rotational torque for increasing the rotational speed of the internal combustion engine engine is output from the motor generator, and the internal combustion engine is activated when the required torque falls below the predetermined torque range. A negative rotational torque for decelerating the rotational speed of the internal combustion engine engine is output from the motor generator by generating electric power using the driving force of the engine.

  According to the hybrid type construction machine of the present invention, the fuel consumption rate can be further improved as the required load increases or decreases.

It is a perspective view showing the appearance of the hybrid type construction machine concerning one embodiment of the present invention. It is a block diagram which shows internal structures, such as an electric system and a hydraulic system, of a hybrid type construction machine. It is a figure which shows the internal structure of the electrical storage means in FIG. It is a block diagram which shows a part of internal structure of a controller. It is a control block diagram which shows the functional relationship between the components of a hybrid type construction machine. It is a graph which shows the equal fuel consumption rate curve of an engine. It is a figure for demonstrating the operation | movement at the time of changing an engine speed along a reference | standard torque line, and has shown a part of graph shown in FIG. It is a block diagram which shows a part of internal structure of the controller which concerns on a modification. It is a control block diagram which shows the functional relationship between the components of the hybrid type construction machine in a modification. It is a block diagram which shows internal structures, such as an electric system and a hydraulic system, of a hybrid type construction machine.

  Embodiments of a hybrid construction machine according to the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view showing an appearance of a hybrid construction machine according to an embodiment of the present invention. The hybrid construction machine 1 of the present embodiment is a so-called power shovel. As shown in FIG. 1, a hybrid construction machine 1 according to this embodiment includes a traveling mechanism 2 including an endless track, and a revolving body 4 that is rotatably mounted on an upper portion of the traveling mechanism 2 via a revolving mechanism 3. And. The swing body 4 is attached with a boom 5, an arm 6 linked to the tip of the boom 5, and a bucket 7 linked to the tip of the arm 6. The boom 5, the arm 6, and the bucket 7 are hydraulically driven by a boom cylinder 8, an arm cylinder 9, and a bucket cylinder 10, respectively. Further, the revolving body 4 is provided with a power source such as a driver's cab 4a for accommodating an operator who operates the position and angle of the bucket 7, and an engine (internal combustion engine engine) 11 for generating hydraulic pressure. Yes. The engine 11 is composed of, for example, a diesel engine.

  FIG. 2 is a block diagram showing an internal configuration such as an electric system and a hydraulic system of the hybrid construction machine 1 of the present embodiment. In FIG. 2, the mechanical power transmission system is indicated by a double line, the hydraulic system is indicated by a thick solid line, the steering system is indicated by a broken line, and the electrical system is indicated by a thin solid line. FIG. 3 is a diagram showing an internal configuration of the power storage means 120 in FIG.

  As shown in FIG. 2, the hybrid construction machine 1 includes a motor generator 12 and a transmission 13, and the rotation shafts of the engine 11 and the motor generator 12 are both connected to the input shaft of the transmission 13. Are connected to each other. When the load on the output of the engine 11 is large, the motor generator 12 drives the engine 11 to assist (assist) the driving force of the engine 11, and the driving force of the motor generator 12 drives the output shaft of the transmission 13. Then, it is transmitted to the main pump 14. On the other hand, when the load on the output of the engine 11 is small, the driving force of the engine 11 is transmitted to the motor generator 12 via the transmission 13 so that the motor generator 12 generates power. The motor generator 12 is configured by, for example, an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in the rotor. Switching between driving and power generation of the motor generator 12 is performed according to the load of the engine 11 and the like by the controller 30A that performs drive control of the electric system in the hybrid type construction machine 1.

  A main pump 14 is connected to the output shaft of the transmission 13. The main pump 14 is a hydraulic pump for generating pressure oil by the driving force of the engine 11, and has a pump control valve 14A for controlling the tilt angle. The pump control valve 14A is configured by an electromagnetic proportional valve connected to a gear pump, and the tilt angle of the main pump 14 is controlled by electrically driving the electromagnetic proportional valve by the controller 30A. . The pressure oil discharged from the main pump 14 is travel hydraulic motors 2a and 2b, a swing hydraulic motor 2c, a boom cylinder 8, an arm cylinder 9, and a bucket cylinder 10 for driving the travel mechanism 2 shown in FIG. Are supplied to the control valve 17 through the high-pressure hydraulic line 16.

  The control valve 17 is a device that controls a hydraulic system in the hybrid construction machine 1. Connected to the control valve 17 are traveling hydraulic motors 2a and 2b, a turning hydraulic motor 2c, a boom cylinder 8, an arm cylinder 9, and a bucket cylinder 10 via a high-pressure hydraulic line. The hydraulic pressure supplied to the vehicle is controlled according to the operation input of the driver.

  A pilot pump 15 is connected to the main pump 14. The pilot pump 15 is a hydraulic pump for generating a pilot pressure necessary for the hydraulic operation system. An operation device 26 is connected to the pilot pump 15 via a pilot line 25. The operation device 26 is an operation device for operating the traveling mechanism 2, the boom 5, the arm 6, and the bucket 7 and is operated by an operator. A control valve 17 is connected to the operating device 26 via a hydraulic line 27. The operating device 26 converts the hydraulic pressure (primary hydraulic pressure) supplied through the pilot line 25 into a hydraulic pressure (secondary hydraulic pressure) corresponding to the operation amount of the operator and outputs the hydraulic pressure. The secondary hydraulic pressure output from the operating device 26 is supplied to the control valve 17 through the hydraulic line 27.

  The output terminal of the inverter circuit 18 is connected to the electrical terminal of the motor generator 12. The power storage means 120 is connected to the input terminal of the inverter circuit 18. As shown in FIG. 3, the power storage means 120 includes a DC bus 110 that is a DC bus, a step-up / down converter 100, and a capacitor 19. That is, the input terminal of the inverter circuit 18 is connected to the input terminal of the step-up / down converter 100 via the DC bus 110. A capacitor 19 as a power storage device is connected to the output terminal of the buck-boost converter 100. The DC bus 110 includes a capacitor 110a. Here, in place of the capacitor 19, a chargeable / dischargeable secondary battery such as a lithium ion battery, or another form of power supply capable of power transfer may be used as the power storage device.

  The inverter circuit 18 controls the operation of the motor generator 12 based on a command from the controller 30A. That is, when the inverter circuit 18 power-operates the motor generator 12, necessary power is supplied from the capacitor 19 and the step-up / down converter 100 to the motor generator 12 via the DC bus 110. Further, when the motor generator 12 is regeneratively operated, the electric power generated by the motor generator 12 is charged into the capacitor 19 via the DC bus 110 and the step-up / down converter 100. The switching control between the step-up / step-down operation of the step-up / step-down converter 100 is performed by the controller 30A based on the DC bus voltage value, the capacitor voltage value, and the capacitor current value. As a result, the DC bus 110 can be maintained in a state of being stored at a predetermined constant voltage value.

  Note that the buck-boost converter 100 of this embodiment has a switching control system, and as shown in FIG. 3, transistors 100a and 100b connected in series with each other, their connection point, and the positive terminal of the capacitor 19 , A diode 100c connected in parallel in the reverse direction to the transistor 100a, and a diode 100d connected in parallel in the reverse direction to the transistor 100b. The transistors 100a and 100b are configured by, for example, an IGBT (Insulated Gate Bipolar Transistor). When DC power is supplied from the capacitor 19 to the DC bus 110, a PWM (Pulse Width Modulation) voltage is applied to the gate of the transistor 100a according to a command from the controller 30A. Then, the induced electromotive force generated in the reactor 101 when the transistor 100a is turned on / off is transmitted through the diode 100d, and this power is smoothed by the capacitor 110a of the DC bus 110. When supplying DC power from the DC bus 110 to the capacitor 19, a PWM voltage is applied to the gate of the transistor 100 b according to a command from the controller 30 A, and the current output from the transistor 100 b is smoothed by the reactor 101. Is done.

  The controller 30A constitutes a control unit in the present embodiment. The controller 30A is configured by an arithmetic processing unit including a CPU and an internal memory, and is realized by the CPU executing a drive control program stored in the internal memory. The power source of the controller 30A is a battery (for example, a 24V on-vehicle battery) different from the capacitor 19. The controller 30 </ b> A performs operation control (switching between assist operation and power generation operation) of the motor generator 12 and charge / discharge control of the capacitor 19 by drivingly controlling the buck-boost converter 100.

  FIG. 4 is a block diagram showing a part of the internal configuration of the controller 30A. As shown in FIG. 4, the controller 30 </ b> A includes a load estimation unit 31, a torque deviation calculation unit 32, a load determination unit 33, and a command value calculation unit 34.

  The load estimation unit 31 is a part for estimating a load required for the hybrid construction machine 1, that is, a load applied to the engine 11. The load estimation unit 31 inputs a hydraulic load signal Sg1 indicating the magnitude of the hydraulic load in the main pump 14 and an electric load signal Sg2 indicating the magnitude of the electric load in the motor generator 12. In FIG. 4, the sign of the electrical load signal Sg2 is positive during assist and negative during power generation. The load estimating unit 31 generates an engine load signal Sg3 indicating a load applied to the engine 11 by calculating a difference between the hydraulic load signal Sg1 and the electric load signal Sg2. As shown in FIG. 4, the load estimation unit 31 may include an efficiency multiplication unit 31a that multiplies the electric load signal Sg2 by the driving efficiency of the motor generator 12.

The torque deviation calculation unit 32 is a part that calculates the deviation between the required torque calculated from the load and the reference torque. The torque deviation calculation unit 32 receives the engine load signal Sg3 from the load estimation unit 31. Further, the torque deviation calculation unit 32 inputs a speed signal Sg4 that is provided from a rotation speed sensor (speed detection unit) that detects the rotation speed of the engine 11 and indicates a detected value of the rotation speed (engine speed) of the engine 11. To do. Based on these signals Sg3 and Sg4 and the reference torque of the engine 11, the torque deviation calculation unit 32 calculates a torque deviation Δt from the following formula (1). However, in Formula (1), Duty is a load applied to the engine 11, Re is a rotation speed detection value of the engine 11, and Tr is a reference torque. The torque deviation calculation unit 32 generates a deviation signal Sg5 indicating the torque deviation Δt.

  The load determination unit 33 receives the deviation signal Sg5 from the torque deviation calculation unit 32, and whether or not the torque deviation Δt exceeds a predetermined positive threshold and whether or not the torque deviation Δt is below a predetermined negative threshold. Determine whether. In other words, the load determination unit 33 determines whether the necessary torque calculated from the load is included in a predetermined torque range corresponding to the rotation speed detection value. Here, the predetermined torque range is set so as to include a reference torque line TS passing through the low fuel consumption region in the equal fuel consumption rate curve of the engine 11 shown in FIG. For example, the predetermined torque range is a range defined by the upper limit torque line Tmax and the lower limit torque line Tmin shown in FIG.

  When the necessary torque is included in the predetermined torque range, the load determination unit 33 generates a determination signal Sg6 indicating a medium load. When the required torque exceeds the predetermined torque range, the load determination unit 33 generates a determination signal Sg6 indicating a high load. When the required torque is below the predetermined torque range, the load determination unit 33 generates a determination signal Sg6 indicating a low load. The load determination unit 33 provides the determination signal Sg6 to the command value calculation unit 34.

  The command value calculation unit 34 calculates the following command values based on the determination signal Sg6 provided from the load determination unit 33. The command value calculation unit 34 calculates a command value related to the rotation speed (rotation speed) of the engine 11, and provides an engine rotation speed command signal Sg7 related to this command value to the ECU. The command value calculation unit 34 calculates a command value related to the hydraulic pressure of the main pump 14, and provides a pump horsepower setting signal Sg8 related to this command value to the pump control valve 14A (see FIG. 2).

  In the present embodiment, when the command value calculation unit 34 determines that the load is high at the point A in FIG. 7, based on the reference torque line Tr, the engine speed is increased from R1 to R2. An engine speed command signal Sg7 is generated. At the same time, the command value calculator 34 calculates the value of the engine output P5 shown in FIG. When it is determined that the load is low at the point C, the engine speed command signal Sg7 is generated based on the reference torque line Tr so as to decrease the engine speed from R3 to R2. At the same time, the command value calculator 34 calculates the value of the engine output P5. Further, the command value calculation unit 34 obtains a pump horsepower setting signal Sg8 based on the calculated engine output P5 and the hydraulic load signal Sg1. Further, the command value calculation unit 34 calculates the assist motor output Pa based on the hydraulic load signal Sg1 and the engine output P5 (Pa = Sg1-P5). Then, an assist motor torque command signal Sg9 described later is calculated by dividing the obtained assist motor output Pa by the speed signal Sg10.

  FIG. 5 is a control block diagram showing a functional relationship between components of the hybrid construction machine 1. FIG. 5 shows a part of the internal configuration of the controller 30A, the engine 11, the motor generator 12, the transmission 13, the engine controller unit (ECU) 40 that controls the engine 11, and the rotational speed sensors 41 and 42. Is shown. The rotation speed sensor 41 is a rotation speed detection unit that detects the rotation speed of the engine 11, and generates the speed signal Sg4 described above. The rotation speed sensor 42 is a sensor that detects the rotation speed of the motor generator 12.

  As shown in FIG. 5, the rotational torque Tm of the motor generator 12 is multiplied by N by the transmission 13 and input to the engine 11. Here, N is a reduction ratio of the transmission 13. In the engine 11, the sum of the torque Tm multiplied by N and the torque Te generated by the engine 11 itself is input, and the rotation speed (the number of rotations) R is output. The rotational speed (rotational speed) Re of the engine 11 is detected by the rotational speed sensor 41, and a speed signal Sg4 related to the rotational speed Re is sent to the ECU 40. The rotational speed Rm of the motor generator 12 is expressed as a numerical value obtained by multiplying the rotational speed Re by N, and is detected by the rotational speed sensor 42. The rotation speed sensor 42 provides a speed signal Sg10 related to the rotation speed Rm to the controller 30A.

  The ECU 40 calculates the difference between the engine speed command signal Sg7 generated in the controller 30A and the speed signal Sg4 related to the current rotational speed Re of the engine 11. Based on this difference, the speed control unit 40a of the ECU 40 calculates the injection amount. For example, PID control is used to calculate the injection amount. The injection amount limiting unit 40b of the ECU 40 determines the fuel flow rate based on the injection amount, and generates a fuel command signal Sg11 for commanding the fuel flow rate. Note that when the injection amount exceeds the allowable upper limit value, the fuel flow rate is limited so as not to exceed the allowable upper limit value. The engine 11 is controlled based on the fuel command signal Sg11 generated in this way.

  As illustrated in FIG. 5, the controller 30A further includes a torque calculation unit 35, a speed control unit 36, a switch unit 37, a torque control unit 38, and a control method determination unit 39A. The torque calculation unit 35 receives the assist motor torque command signal Sg9 and the speed signal Sg10 provided from the rotation speed sensor 42. The torque calculation unit 35 calculates a torque command value Ta1 for the motor generator 12 based on these signals Sg9 and Sg10.

  Further, the speed control unit 36 includes a deviation between a value obtained by multiplying the rotation speed command value indicated by the engine speed command signal Sg7 by a reduction ratio (N) and the rotation speed Rm of the motor generator 12 indicated by the speed signal Sg10. Is entered. The speed control unit 36 calculates a torque command value Ta2 for the motor generator 12 based on this deviation.

  The switch unit 37 selects one of the torque command value Ta1 and the torque command value Ta2, and inputs the selected value to the torque control unit 38. Selection of the switch unit 37 is controlled by the control method determination unit 39A. The control method determination unit 39A receives the engine speed command signal Sg7, the speed signal Sg4, and the fuel command signal Sg11, and controls the switch unit 37 based on these signals. The torque control unit 38 outputs a signal for controlling the motor generator 12 to the inverter circuit 18 (see FIG. 2) so that the output torque of the motor generator 12 approaches the value selected by the switch unit 37.

  Here, the control method of the switch unit 37 by the control method determination unit 39A will be further described. First, the control method determination unit 39A calculates the current output (power) of the engine 11 based on the rotational speed Re of the engine 11 indicated by the speed signal Sg4. Subsequently, the control method determination unit 39A calculates a deviation between the rotation speed Re of the engine 11 and the rotation speed target value corresponding to the load on the engine 11 indicated by the engine rotation speed command signal Sg7. Then, when this deviation is included in a predetermined range, the control method determination unit 39A switches the switch unit to select the torque command value Ta1 in order to perform control according to the difference between the current engine output and the load. 37 is controlled (torque control mode). At this time, the controller 30A keeps the engine speed command signal Sg7 constant in order to maintain the current rotational speed Re of the engine 11.

  On the other hand, the control method determination unit 39A controls the switch unit 37 to select the torque command value Ta2 when the deviation deviates from a predetermined range (speed control mode). When the deviation exceeds a predetermined range, the speed control unit 36 generates a torque command value Ta2 so that the rotational speed Re of the engine 11 increases. As a result, the controller 30 </ b> A outputs a positive rotational torque for increasing the rotational speed Re from the motor generator 12. When the deviation falls below a predetermined range, the speed control unit 36 generates a torque command value Ta2 so that the rotational speed Re of the engine 11 is reduced. Specifically, the speed control unit 36 generates the torque command value Ta <b> 2 so that the motor generator 12 generates power with the driving force of the engine 11. As a result, the controller 30A causes the motor generator 12 to output a negative rotational torque for decelerating the rotational speed Re. Here, when the torque control mode is switched to the speed control mode, it is necessary to prevent a sudden change in torque. For this reason, the control signal output from the torque control unit 38 during the speed control mode adds the torque command value Ta2 generated in the speed control mode to the torque command value Ta1 used last in the torque control mode, Or, it is output after subtraction.

  The predetermined range described above will be further described. FIG. 6 is a graph showing an equal fuel consumption rate curve of the engine 11. In this graph, the lower limit value of the rotational speed of the engine 11 is indicated as the rotational speed L, and the upper limit value is indicated as the rotational speed H. The rotational speed of the engine 11 is controlled to be included between the rotational speed L and the rotational speed H. The vertical axis in FIG. 6 represents engine torque (Nm), and the horizontal axis represents engine speed (rpm). In FIG. 6, the equal output line of the engine 11 is indicated by a dotted line, the equal fuel consumption line is indicated by a thick solid line, and the reference torque line TS is indicated by a thick one-dot chain line.

  The reference torque line TS is a continuous line connecting points where the rotational torque of the engine 11 is close to the maximum value and the fuel consumption rate is low. This reference torque line TS is a line connecting points where the fuel consumption rate becomes low in a region close to the maximum value of the rotational torque at the rotational speed when the rotational speed of the engine 11 is changed. It is preset based on the equal fuel consumption rate curve.

  When the rotational torque of the engine 11 is smaller than the minimum value of the reference torque line TS, the rotational speed of the engine 11 is set to a rotational speed L that is a lower limit value. At this time, even if the rotational torque required for the engine 11 increases, the engine rotational speed is maintained constant (rotational speed L). That is, the operating state of the engine 11 changes along the arrow A1 in FIG. When the rotational torque required for the engine 11 increases and reaches the minimum value of the reference torque line TS, the rotational torque of the engine 11 is controlled by making the rotational speed of the engine 11 variable. That is, the operating state of the engine 11 changes in the direction of the arrow A2 in FIG. 6 along the reference torque line TS.

  FIG. 7 is a diagram for explaining an operation when the rotational speed of the engine 11 is changed along the reference torque line TS, and shows a part of the graph shown in FIG. The upper limit torque line Tmax is set on the side where the rotational torque is large around the reference torque line TS, and the lower limit torque line Tmin is set on the small side.

  Now, it is assumed that the engine 11 is outputting the rotational speed and rotational torque on the reference torque line TS (point A in FIG. 7). When a rotational torque larger than the current rotational torque is requested (that is, when the engine load increases), the control method determination unit 39A causes the engine 11 indicated by the rotational speed Re of the engine 11 and the engine rotational speed command signal Sg7. This requirement is known based on the deviation from the target rotational speed corresponding to the load on the motor. Then, when this deviation is included in a predetermined range, that is, when the required rotational torque is smaller than the upper limit torque line Tmax, the control method determination unit 39A performs control according to the difference between the current engine output and the load. For this purpose, the switch unit 37 is controlled so as to select the torque command value Ta1 (torque control mode). At this time, the controller 30A keeps the engine speed command signal Sg7 constant, so that as shown in FIG. 7, the operating state of the engine 11 is the direction in which the speed is constant and the torque increases, that is, the arrow from the point A It changes in the direction of a.

When the rotational torque required for the engine 11 increases from the reference torque line TS by Δt ₁ and reaches the upper limit torque line Tmax (point B in FIG. 7), the rotational speed Re of the engine 11 and the engine rotational speed command signal Sg7 The deviation from the rotation speed target value corresponding to the load applied to the engine 11 exceeds the predetermined range described above. At this time, the speed control unit 36 generates the torque command value Ta2 so that the rotational speed of the engine 11 increases. Further, the control method determination unit 39A controls the switch unit 37 so as to select the torque command value Ta2 (speed control mode). Thereby, the motor generator 12 outputs a positive rotational torque for increasing the rotational speed of the engine 11. At this time, the rotational speed of the engine 11 increases by a predetermined rotational speed Δr ₁ . This increase in rotational speed is indicated by an arrow b in FIG.

When the number of revolutions of the engine 11 is increased by Δr ₁ , the output increases accordingly, and the operation of the engine 11 moves to a point C. Here, the rotational torque currently required for the engine 11 is the rotational torque at the point B. Therefore, by shifting the operating state of the engine 11 from the point C in the direction indicated by the arrow c, the rotational torque of the engine 11 is reduced by Δt ₂ . As a result, the operation of the engine 11 moves from point C to point D. Point B and point D have the same engine output, and point D is a point moved from point B along the iso-output line. That is, the point D is an intersection of the iso-output line passing through the point B and the reference torque line TS.

As described above, when the engine 11 is subjected to a high load and the rotational torque is increased, an increase Δr ₁ of the engine speed corresponding to the torque deviation Δt ₁ from the reference torque line TS is obtained, and the target of the engine 11 is obtained. The number of revolutions is updated to a value obtained by adding Δr ₁ to the current number of revolutions Re (Re + Δr ₁ ). Then, a power running command is sent to the inverter circuit 18 of the motor generator 12 so that the rotation speed of the engine 11 approaches the updated target rotation speed (Re + Δr ₁ ). As a result, the fuel consumption rate along the reference torque line TS can be achieved while increasing the output by increasing the rotational speed of the engine 11.

  Further, it is assumed that the engine 11 outputs the rotational speed and rotational torque on the reference torque line TS (point E in FIG. 7). When a rotational torque smaller than the current rotational torque is requested (that is, when the engine load is reduced), the control method determination unit 39A causes the engine 11 indicated by the rotational speed Re of the engine 11 and the engine rotational speed command signal Sg7. This requirement is known based on the deviation from the target rotational speed corresponding to the load on the motor. Then, when this deviation is included in a predetermined range, that is, when the required rotational torque is smaller than the lower limit torque line Tmin, the control method determination unit 39A performs control according to the difference between the current engine output and the load. For this purpose, the switch unit 37 is controlled so as to select the torque command value Ta1 (torque control mode). At this time, the controller 30A keeps the engine speed command signal Sg7 constant, so as shown in FIG. 7, the operating state of the engine 11 is in the direction in which the speed is constant and the torque decreases, that is, from the point E to the arrow. It changes in the direction of e.

When the rotational torque required for the engine 11 decreases by Δt ₃ from the reference torque line TS and reaches the lower limit torque line Tmin (point F in FIG. 7), the rotational speed Re of the engine 11 and the engine rotational speed command signal Sg7 The indicated deviation from the target rotational speed value corresponding to the load on the engine 11 falls below the predetermined range described above. At this time, the speed control unit 36 generates the torque command value Ta2 so that the rotational speed of the engine 11 is decreased. Further, the control method determination unit 39A controls the switch unit 37 so as to select the torque command value Ta2 (speed control mode). Thereby, the motor generator 12 outputs a negative rotational torque for reducing the rotational speed of the engine 11. That is, the motor generator 12 generates power using the driving force of the engine 11. At this time, the rotational speed of the engine 11 decreases by a predetermined rotational speed Δr ₂ . This decrease in the rotational speed is indicated by an arrow f in FIG.

When the rotational speed of the engine 11 is decreased by Δr ₂ , the output is also decreased accordingly, and the operation of the engine 11 moves to a point G. Since the rotational torque currently required for the engine 11 is the rotational torque at the point F, the rotational torque of the engine 11 is increased by Δt ₄ by shifting the operating state of the engine 11 from the point G in the direction indicated by the arrow g. As a result, the operation of the engine 11 moves from point G to point D. Point F and point D have the same engine output, and point D is a point moved from point F along the iso-output line. That is, the point D is an intersection between the iso-output line passing through the point F and the reference torque line TS.

As described above, when the load of the engine 11 is reduced to reduce the rotational torque, the increase amount Δr ₂ of the engine speed corresponding to the torque deviation Δt ₃ from the reference torque line TS is obtained, and the target of the engine 11 is obtained. The number of revolutions is updated to a value obtained by subtracting Δr ₂ from the current number of revolutions Re (Re−Δr ₂ ). Then, a power generation command is sent to the inverter circuit 18 of the motor generator 12 so that the rotation speed of the engine 11 approaches the updated target rotation speed (Re−Δr ₂ ). As a result, the fuel consumption rate along the reference torque line TS can be achieved while decreasing the engine speed and decreasing the output.

  In the hybrid construction machine 1 described above, the engine 11 is operated under the condition that the fuel consumption rate is low while controlling the rotation speed of the engine 11 to an arbitrary rotation speed along the reference torque line TS within a predetermined range. Make it work. Further, when the rotational torque exceeds (or falls below) a predetermined range centered on the reference torque line TS, the engine 11 is operated under the condition that the fuel consumption rate is lowered by variably controlling the engine rotational speed. Therefore, according to the hybrid type construction machine 1 of the present embodiment, the fuel consumption rate can be further improved with respect to increase / decrease in the required load.

(First modification)
Next, a modification of the above embodiment will be described. Note that, among the configurations of the hybrid type construction machine according to this modification, the configuration other than the controller is the same as that of the hybrid type construction machine 1 described above, and thus detailed description thereof is omitted.

  FIG. 8 is a block diagram showing a part of the internal configuration of the controller 30B according to this modification. As shown in FIG. 8, the controller 30 </ b> B includes a load estimation unit 31, a torque deviation calculation unit 32, a load determination unit 33, and a command value calculation unit 34. The configurations and functions of the load estimation unit 31 and the torque deviation calculation unit 32 are the same as those in the above-described embodiment.

  The load determination unit 33 receives the deviation signal Sg5 from the torque deviation calculation unit 32, and whether or not the torque deviation Δt exceeds a predetermined positive threshold and whether or not the torque deviation Δt is below a predetermined negative threshold. Determine whether. In other words, the load determination unit 33 determines whether the necessary torque calculated from the load is included in a predetermined torque range corresponding to the rotation speed detection value. Here, the predetermined torque range is set so as to include a reference torque line TS passing through the low fuel consumption region in the equal fuel consumption rate curve of the engine 11 shown in FIG. For example, the predetermined torque range is a range defined by the upper limit torque line Tmax and the lower limit torque line Tmin shown in FIG.

  When the necessary torque is included in the predetermined torque range, the load determination unit 33 generates a determination signal Sg6 indicating a medium load. When the required torque exceeds the predetermined torque range, the load determination unit 33 generates a determination signal Sg6 indicating a high load. When the required torque is below the predetermined torque range, the load determination unit 33 generates a determination signal Sg6 indicating a low load. The load determination unit 33 provides the determination signal Sg6 to the command value calculation unit 34.

  The command value calculation unit 34 calculates the following command values based on the determination signal Sg6 provided from the load determination unit 33. The command value calculation unit 34 calculates a command value related to the rotation speed (rotation speed) of the engine 11, and provides an engine rotation speed command signal Sg7 related to this command value to the ECU. The command value calculation unit 34 calculates a command value related to the hydraulic pressure of the main pump 14, and provides a pump horsepower setting signal Sg8 related to this command value to the pump control valve 14A (see FIG. 2).

  In the present embodiment, when the command value calculation unit 34 determines that the load is high at the point A in FIG. 7, based on the reference torque line Tr, the engine speed is increased from R1 to R2. An engine speed command signal Sg7 is generated. At the same time, the command value calculator 34 calculates the value of the engine output P5 shown in FIG. When it is determined that the load is low at the point C, the engine speed command signal Sg7 is generated based on the reference torque line Tr so as to decrease the engine speed from R3 to R2. At the same time, the command value calculator 34 calculates the value of the engine output P5. Further, the command value calculation unit 34 obtains a pump horsepower setting signal Sg8 based on the calculated engine output P5 and the hydraulic load signal Sg1. Further, the command value calculation unit 34 calculates the assist motor output Pa based on the hydraulic load signal Sg1 and the engine output P5 (Pa = Sg1-P5). Then, an assist motor torque command signal Sg9 described later is calculated by dividing the obtained assist motor output Pa by the speed signal Sg10.

  FIG. 9 is a control block diagram showing a functional relationship between components of the hybrid type construction machine in this modification. FIG. 9 shows a part of the internal configuration of the controller 30B, the engine 11, the motor generator 12, the transmission 13, the ECU 40 that controls the engine 11, and the rotation speed sensors 41 and 42. . Of these components, the configuration other than the controller 30B is the same as that of the above embodiment.

  The controller 30B further includes a torque calculation unit 35, a speed control unit 36, a switch unit 37, a torque control unit 38, and a control method determination unit 39B. The torque calculation unit 35 receives the assist motor torque command signal Sg9 and the speed signal Sg10 provided from the rotation speed sensor 42. The torque calculation unit 35 calculates a torque command value Ta1 for the motor generator 12 based on these signals Sg9 and Sg10.

  Further, the speed control unit 36 includes a deviation between a value obtained by multiplying the rotation speed command value indicated by the engine speed command signal Sg7 by a reduction ratio (N) and the rotation speed Rm of the motor generator 12 indicated by the speed signal Sg10. Is entered. The speed control unit 36 calculates a torque command value Ta2 for the motor generator 12 based on this deviation.

  The switch unit 37 selects one of the torque command value Ta1 and the torque command value Ta2, and inputs the selected value to the torque control unit 38. Selection of the switch unit 37 is controlled by the control method determination unit 39B. The control method determination unit 39B receives the determination signal Sg6 from the load determination unit 33 (see FIG. 8), and controls the switch unit 37 based on the determination signal Sg6. The torque control unit 38 outputs a signal for controlling the motor generator 12 to the inverter circuit 18 (see FIG. 2) so that the output torque of the motor generator 12 approaches the value selected by the switch unit 37.

Here, the control method of the switch unit 37 by the control method determination unit 39B will be further described. When the determination signal Sg6 indicates a medium load, that is, when the necessary torque calculated from the load is included in a predetermined torque range corresponding to the detected rotational speed, the control method determination unit 39B determines the current engine output and the load. In order to perform control according to the difference between the switch unit 37 and the switch unit 37 so as to select the torque command value Tb ₁ (torque control mode). At this time, the controller 30B keeps the engine speed command signal Sg7 constant in order to maintain the current rotational speed Re of the engine 11.

On the other hand, the control method determining unit 39B, if the required torque deviates from the predetermined torque range, to control the switching unit 37 to select the torque command value Tb ₂ (speed control mode). When the required torque exceeds the predetermined torque range, the speed control unit 36 generates the torque command value Tb ₂ so that the rotational speed Re of the engine 11 increases. Thus, the controller 30B outputs from the motor generator 12 a positive rotational torque for increasing the rotational speed Re. Further, when the required torque falls below the predetermined torque range, the speed control unit 36 generates the torque command value Tb ₂ so that the rotational speed Re of the engine 11 is reduced. Specifically, the speed control unit 36 generates the torque command value Tb ₂ so that the motor generator 12 generates power with the driving force of the engine 11. As a result, the controller 30B causes the motor generator 12 to output a negative rotational torque for decelerating the rotational speed Re. Here, when the torque control mode is switched to the speed control mode, it is necessary to prevent a sudden change in torque. For this reason, the control signal output from the torque control unit 38 during the speed control mode uses the torque command value Tb ₂ generated in the speed control mode with respect to the torque command value Tb ₁ used last in the torque control mode. Output after addition or subtraction.

  With reference to FIGS. 6 and 7 again, the predetermined torque range in the present modification will be further described. Also in this modification, the rotation speed of the engine 11 is controlled to be included between the rotation speed L and the rotation speed H. When the rotational torque of the engine 11 is smaller than the minimum value of the reference torque line TS, the rotational speed of the engine 11 is set to a rotational speed L that is a lower limit value. At this time, even if the rotational torque required for the engine 11 increases, the engine rotational speed is maintained constant (rotational speed L). That is, the operating state of the engine 11 changes along the arrow A1 in FIG. When the rotational torque required for the engine 11 increases and reaches the minimum value of the reference torque line TS, the rotational torque of the engine 11 is controlled by making the rotational speed of the engine 11 variable. That is, the operating state of the engine 11 changes in the direction of the arrow A2 in FIG. 6 along the reference torque line TS.

  Now, it is assumed that the engine 11 is outputting the rotational speed and rotational torque on the reference torque line TS (point A in FIG. 7). When a rotational torque larger than the current rotational torque is requested (that is, when the engine load increases), if the determination signal Sg6 indicates a medium load, the control method determination unit 39B includes the required torque within a predetermined range. (That is, the required rotational torque is smaller than the upper limit torque line Tmax). At this time, the control method determination unit 39B controls the switch unit 37 to select the torque command value Ta1 in order to perform control according to the difference between the current engine output and the load (torque control mode). At this time, the controller 30B keeps the engine speed command signal Sg7 constant, so as shown in FIG. 7, the operating state of the engine 11 is the direction in which the engine speed is constant and the torque increases, that is, the arrow from the point A It changes in the direction of a.

When the rotational torque required for the engine 11 increases by Δt ₁ from the reference torque line TS and reaches the upper limit torque line Tmax (point B in FIG. 7), the determination signal Sg6 indicates a high load. That is, the required torque exceeds a predetermined range. At this time, the speed control unit 36 generates the torque command value Ta2 so that the rotational speed of the engine 11 increases. Further, the control method determination unit 39B controls the switch unit 37 so as to select the torque command value Ta2 (speed control mode). Thereby, the motor generator 12 outputs a positive rotational torque for increasing the rotational speed of the engine 11. At this time, the rotational speed of the engine 11 increases by a predetermined rotational speed Δr ₁ . This increase in rotational speed is indicated by an arrow b in FIG.

When the number of revolutions of the engine 11 is increased by Δr ₁ , the output increases accordingly, and the operation of the engine 11 moves to a point C. Here, the rotational torque currently required for the engine 11 is the rotational torque at the point B. Therefore, by shifting the operating state of the engine 11 from the point C in the direction indicated by the arrow c, the rotational torque of the engine 11 is reduced by Δt ₂ . As a result, the operation of the engine 11 moves from point C to point D. Point D is the intersection of the iso-output line passing through point B and the reference torque line TS.

As described above, when the engine 11 is subjected to a high load and the rotational torque is increased, an increase Δr ₁ of the engine speed corresponding to the torque deviation Δt ₁ from the reference torque line TS is obtained, and the target of the engine 11 is obtained. The number of revolutions is updated to a value obtained by adding Δr ₁ to the current number of revolutions Re (Re + Δr ₁ ). Then, a power running command is sent to the inverter circuit 18 of the motor generator 12 so that the rotation speed of the engine 11 approaches the updated target rotation speed (Re + Δr ₁ ). As a result, the fuel consumption rate along the reference torque line TS can be achieved while increasing the output by increasing the rotational speed of the engine 11.

  Further, it is assumed that the engine 11 outputs the rotational speed and rotational torque on the reference torque line TS (point E in FIG. 7). When a rotational torque smaller than the current rotational torque is requested (that is, when the engine load increases), if the determination signal Sg6 indicates a medium load, the control method determination unit 39B includes the required torque within a predetermined range. (That is, the required rotational torque is greater than the lower limit torque line Tmin). At this time, the control method determination unit 39B controls the switch unit 37 to select the torque command value Ta1 in order to perform control according to the difference between the current engine output and the load (torque control mode). At this time, the controller 30B keeps the engine speed command signal Sg7 constant, so as shown in FIG. 7, the operating state of the engine 11 is in the direction in which the speed is constant and the torque decreases, that is, from the point E to the arrow. It changes in the direction of e.

When the rotational torque required for the engine 11 decreases by Δt ₃ from the reference torque line TS and reaches the lower limit torque line Tmin (point F in FIG. 7), the determination signal Sg6 indicates a low load. That is, the required torque has fallen below the predetermined range. At this time, the speed control unit 36 generates the torque command value Ta2 so that the rotational speed of the engine 11 is decreased. Further, the control method determination unit 39B controls the switch unit 37 so as to select the torque command value Ta2 (speed control mode). Thereby, the motor generator 12 outputs a negative rotational torque for reducing the rotational speed of the engine 11. That is, the motor generator 12 generates power using the driving force of the engine 11. At this time, the rotational speed of the engine 11 decreases by a predetermined rotational speed Δr ₂ . This decrease in the rotational speed is indicated by an arrow f in FIG.

When the rotational speed of the engine 11 is decreased by Δr ₂ , the output is also decreased accordingly, and the operation of the engine 11 moves to a point G. Since the rotational torque currently required for the engine 11 is the rotational torque at the point F, the rotational torque of the engine 11 is increased by Δt ₄ by shifting the operating state of the engine 11 from the point G in the direction indicated by the arrow g. As a result, the operation of the engine 11 moves from point G to point D. Point D is the intersection of the iso-output line passing through point F and the reference torque line TS.

As described above, when the load of the engine 11 is reduced to reduce the rotational torque, the increase amount Δr ₂ of the engine speed corresponding to the torque deviation Δt ₃ from the reference torque line TS is obtained, and the target of the engine 11 is obtained. The number of revolutions is updated to a value obtained by subtracting Δr ₂ from the current number of revolutions Re (Re−Δr ₂ ). Then, a power generation command is sent to the inverter circuit 18 of the motor generator 12 so that the rotation speed of the engine 11 approaches the updated target rotation speed (Re−Δr ₂ ). As a result, the fuel consumption rate along the reference torque line TS can be achieved while decreasing the engine speed and decreasing the output.

  In the modification described above, the engine 11 is operated under the condition that the fuel consumption rate is low while controlling the rotational speed of the engine 11 to an arbitrary rotational speed along the reference torque line TS within a predetermined torque range. . Further, when the rotational torque exceeds (or falls below) a predetermined torque range centered on the reference torque line TS, the engine 11 is operated under the condition that the fuel consumption rate is lowered by variably controlling the engine rotational speed. . Therefore, according to the hybrid type construction machine of this modification, the fuel consumption rate can be further improved with respect to increase / decrease in required load.

(Second modification)
FIG. 10 is a block diagram illustrating a configuration of a hybrid construction machine according to another modification. The difference between the present modification and the above embodiment is that a turning electric motor 21 is provided instead of the turning hydraulic motor 2c.

  The inverter circuit 20 is connected to the power storage means 120 of this modification. A turning electric motor 21 is connected to one end of the inverter circuit 20, and the other end of the inverter circuit 20 is connected to the DC bus 110 of the power storage means 120. The turning electric motor 21 is a power source of the turning mechanism 3 for turning the turning body 4. 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.

  When the turning electric motor 21 performs a power running operation, the rotational force of the rotational driving force of the turning electric motor 21 is amplified by the turning speed reducer 24, and the turning body 4 is subjected to acceleration / deceleration control to perform rotational motion. Further, due to the inertial rotation of the swing body 4, the rotation speed is increased by the swing speed reducer 24 and transmitted to the swing electric motor 21 to generate regenerative power. The turning electric motor 21 is AC driven by the inverter circuit 20 by a PWM control signal. As the turning electric motor 21, for example, a magnet-embedded IPM motor is suitable.

  The resolver 22 is a sensor that detects the rotation position and rotation angle of the rotation shaft 21A of the turning electric motor 21, and mechanically connects to the turning electric motor 21 to detect the rotation angle and rotation direction of the rotation shaft 21A. When the resolver 22 detects the rotation angle of the rotation shaft 21A, the rotation angle and the rotation direction of the turning mechanism 3 are derived. The mechanical brake 23 is a braking device that generates a mechanical braking force, and mechanically stops the rotating shaft 21A of the turning electric motor 21 according to a command from the controller 30A. 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 3.

  Since the motor generator 12 and the turning motor 21 are connected to the DC bus 110 via the inverter circuits 18 and 20, the electric power generated by the motor generator 12 is directly supplied to the turning motor 21. In some cases, electric power regenerated by the turning electric motor 21 may be supplied to the motor generator 12.

  A pressure sensor 29 is connected to the operating device 26 via a hydraulic line 28. The secondary hydraulic pressure output from the operating device 26 is detected by the pressure sensor 29. When an operation for turning the turning mechanism 3 is input to the operating device 26, the pressure sensor 29 detects this operation amount as a change in the oil pressure in the hydraulic line 28. The pressure sensor 29 outputs an electrical signal indicating the hydraulic pressure in the hydraulic line 28. This electric signal is input to the controller 30 </ b> A (30 </ b> B) and used for driving control of the turning electric motor 21.

  The controller 30 </ b> A (30 </ b> B) converts a signal representing an operation amount for turning the turning mechanism 3 among signals inputted from the pressure sensor 29 into a speed command, and performs drive control of the turning electric motor 21.

  For example, even with a hybrid construction machine configured as in this modification, the operational effects according to the above-described embodiment can be suitably obtained.

  DESCRIPTION OF SYMBOLS 1 ... Hybrid type construction machine, 2 ... Traveling mechanism, 2a, 2b ... Hydraulic motor, 3 ... Turning mechanism, 4 ... Turning body, 5 ... Boom, 6 ... Arm, 7 ... Bucket, 8 ... Boom cylinder, 9 ... Arm cylinder DESCRIPTION OF SYMBOLS 10 ... Bucket cylinder, 11 ... Engine, 12 ... Motor generator, 13 ... Transmission, 14 ... Main pump, 15 ... Pilot pump, 16 ... High pressure hydraulic line, 17 ... Control valve, 18 ... Inverter circuit, 19 ... Capacitor , 26 ... operating device, 30A, 30B ... controller, 31 ... load estimation section, 32 ... torque deviation calculation section, 33 ... load determination section, 34 ... command value calculation section, 35 ... torque calculation section, 36 ... speed control section, 37 ... Switch unit, 38 ... Torque control unit, 39A, 39B ... Control method determination unit, 40 ... ECU, 41,42 ... Rotational speed sensor, 100 ... Bucking pressure Converter, 101 ... reactor, 110 ... DC bus, 120 ... storage means.

Claims (6)

An internal combustion engine motor;
A speed detector for detecting the rotational speed of the internal combustion engine engine;
A motor generator connected to the internal combustion engine engine, generating electric power with the driving force of the internal combustion engine engine, and assisting the driving force of the internal combustion engine engine with its own driving force;
A storage battery electrically connected to the motor generator;
A control unit for controlling the rotational speed of the engine and the rotational torque of the motor generator;
With
The controller is
Calculating the load of the internal combustion engine motor required in the hybrid construction machine,
The internal combustion engine is maintained while maintaining the rotational speed of the internal combustion engine when the deviation between the rotational speed detection value and the rotational speed target value corresponding to the load of the internal combustion engine is within a predetermined range. Controlling the rotational torque of the motor generator so as to generate power by the driving force of the engine or assist the driving force of the engine of the internal combustion engine,
When the deviation exceeds the predetermined range, a positive rotational torque is output from the motor generator based on the rotational speed target value of the internal combustion engine engine,
When the deviation falls below the predetermined range, a negative rotation torque is output from the motor generator based on the rotation speed target value of the internal combustion engine engine. An internal combustion engine motor;
A speed detector for detecting the rotational speed of the internal combustion engine engine;
A motor generator coupled to the internal combustion engine engine, generating electric power with the driving force of the internal combustion engine engine, and assisting the driving force of the internal combustion engine engine with its own driving force;
A storage battery electrically connected to the motor generator;
A control unit for controlling the rotational speed of the engine and the rotational torque of the motor generator;
With
The controller is
Calculating the load of the internal combustion engine motor required in the hybrid construction machine,
When the required torque calculated from the load of the internal combustion engine engine is included in a predetermined torque range, the power generation by the driving force of the internal combustion engine engine or the internal combustion engine is maintained while maintaining the rotational speed of the internal combustion engine engine. Controlling the rotational torque of the motor generator so as to assist the driving force of the engine engine,
When the required torque exceeds the predetermined torque range, a positive rotational torque is output from the motor generator based on a target rotational speed of the internal combustion engine motor,
When the required torque falls below the predetermined torque range, a negative rotational torque is output from the motor generator based on a target rotational speed of the internal combustion engine engine. .   3. The hybrid type according to claim 1, wherein the control unit includes a switch unit that switches the motor generator from control of rotational torque to control based on a target rotational speed of an internal combustion engine engine. 4. Construction machinery. The controller is
A load determination unit for determining a load of the internal combustion engine motor;
The command value calculating part which produces | generates the said rotational speed target value of the said internal combustion engine engine based on the load determination result by the said load determination part, These are characterized by the above-mentioned. Hybrid construction machine.   The hybrid construction machine according to claim 4, wherein the command value calculation unit of the control unit further generates a pump horsepower setting signal based on the load determination result. An internal combustion engine motor;
A speed detector for detecting the rotational speed of the internal combustion engine engine;
A motor generator coupled to the internal combustion engine engine, generating electric power with the driving force of the internal combustion engine engine, and assisting the driving force of the internal combustion engine engine with its own driving force;
A storage battery electrically connected to the motor generator;
A control unit for controlling the rotational speed of the internal combustion engine engine and the rotational torque of the motor generator,
The controller is
Estimating the load required in the hybrid type construction machine, and calculating the current output of the internal combustion engine motor based on the rotational speed detection value of the internal combustion engine motor provided from the speed detection unit,
When the required torque calculated from the load is included in a predetermined torque range corresponding to the detected rotational speed, the difference between the current output and the load is maintained while maintaining the rotational speed of the engine. According to the control of the rotational torque of the motor generator to generate power by the driving force of the internal combustion engine motor or to assist the driving force of the internal combustion engine motor,
When the required torque exceeds the predetermined torque range, a positive rotational torque for increasing the rotational speed of the internal combustion engine engine is output from the motor generator,
When the required torque falls below the predetermined torque range, a negative rotational torque for decelerating the rotational speed of the internal combustion engine motor is generated by generating electric power using the driving force of the internal combustion engine motor. A hybrid-type construction machine characterized by being output from a generator.

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