JP2012016993A - Control system in hybrid construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve engine efficiency in a hybrid construction machine in which an engine, a hydraulic pump and a power generation electric motor are connected in parallel with one another.SOLUTION: A control system includes: a control device 18 which outputs control commands to an engine controller 17 and a power generation electric motor controller 20; a rotation number switching dial 42 by which an operator switches the number of revolutions of the engine; and a pump output measurement unit for measuring an output of the hydraulic pump 14. The control device sets an engine target rotation number ωs at which the engine efficiency becomes maximum according to a dial value of the rotation number switching dial and a target output Pes, outputs the control command to the engine controller in order to obtain the engine target rotation number ωs, at the same time, operates a power generation electric motor target output Pgs for setting an engine output to the engine target output Pes on the basis of an output of the hydraulic pump, and outputs the control command to the power generation electronic motor controller in order to obtain the power generation electric motor target output Pgs.

Description

  The present invention relates to a technical field of a control system in a hybrid construction machine that is used in combination with an engine and a power storage device as a power source.

  In recent years, also in construction machines such as hydraulic excavators, hybrid type construction machines using an engine and a power storage device in combination as power sources are being put into practical use in order to achieve energy saving, improved fuel consumption, reduced exhaust gas, and the like. As a control system for such a hybrid type construction machine, a so-called parallel control system in which an engine, a hydraulic pump that supplies hydraulic oil to a hydraulic actuator, and a generator and a generator motor that functions as a motor are mechanically connected in parallel. Is conventionally known. Further, in such a parallel system, when the input of the hydraulic pump is smaller than the engine output, the engine is operated between a predetermined set speed and a high idle speed, and the input of the hydraulic pump is more than the engine output. When the engine speed is too large, a technique has been proposed in which the input of the hydraulic pump is reduced and the generator motor is operated to supplement the engine output to operate the engine near the set rotational speed (for example, Patent Document 1). reference.). A technique is also known in which the engine output is automatically increased or decreased so that the power shortage of the power storage device is automatically compensated by the engine power (see, for example, Patent Document 2).

JP 2001-12274 A JP 2008-49761 A

  However, in Patent Document 1, when the input of the hydraulic pump is smaller than the engine output, the engine is operated between a predetermined set rotational speed and a high idle rotational speed (no-load rotational speed). However, in this case, the engine efficiency is best when the engine speed is the set speed, and when the engine speed is higher than the set speed, that is, when the load on the engine is reduced and the engine speed is increased, Engine efficiency decreases. Moreover, in the thing of patent document 2, although the output of an engine increases / decreases automatically, as in the said patent document 1, also in this thing, an engine is between a predetermined setting rotation speed and a no-load rotation speed. When the engine is operated and the engine speed is higher than the set speed, the engine efficiency decreases. Thus, the above-mentioned Patent Documents 1 and 2 have a problem that the engine may be operated in an inefficient state, which hinders improvement in fuel consumption. Furthermore, considering the efficiency of the entire hybrid construction machine, not only the engine efficiency but also the efficiency of the power storage device is a major factor, and there are problems to be solved by the present invention.

The present invention has been made in view of the above-described circumstances in order to solve these problems. The invention of claim 1 is directed to an engine, a hydraulic pump, and pressure oil supply from the hydraulic pump. A load driven by the generator, a generator motor that functions as a generator and a motor, a power transmission mechanism that mechanically connects the engine, the hydraulic pump, and the generator motor in parallel, a motor, and a load driven by the motor And a power storage device having a storage / discharge function, and a hybrid construction machine in which the generator motor, the motor, and the power storage device are connected so that power can be exchanged between them. Engine control means for controlling, generator motor control means for controlling the output of the generator motor, and electric motor for controlling the output, rotation speed or torque of the motor Control means, power transmission intermittent means for intermittently transmitting power by the power transmission mechanism, engine control means, generator motor control means, motor control means, control device for outputting a control command to power transmission intermittent means, and the hydraulic pressure Pump output measuring means for measuring the output of the pump, and the control device sets engine target speed setting means for setting the engine target speed, and engine efficiency according to the set engine target speed. Engine target output setting means for setting an engine target output that maximizes the engine output, and outputs a control command to the engine control means so that the engine speed becomes the engine target speed when the engine is driven, while the pump output Based on the output of the hydraulic pump measured by the measuring means, the engine output is set to the engine target output. It calculates a generator motor target output is the output of the generator motor control system in a hybrid-type construction machine and outputs a control command to the generator motor control means so as to the generator motor target output.
According to a second aspect of the present invention, in the first aspect, the control device calculates the engine target rotational speed and the actual engine speed when calculating the generator motor target output for setting the engine output to the engine target output based on the output of the hydraulic pump. A control system in a hybrid type construction machine is characterized in that a deviation from a number is obtained and a generator motor target output is increased or decreased so as to eliminate the deviation.
According to a third aspect of the present invention, in the first or second aspect, the engine rotational speed switching means for the operator to arbitrarily switch the engine rotational speed is provided, and the engine target rotational speed setting means is an operation value of the engine rotational speed switching means. The control system in the hybrid type construction machine is characterized in that the target engine speed is set according to the above.
According to a fourth aspect of the present invention, in the first or second aspect of the present invention, load measuring means for measuring the power consumed by the load driven by the hydraulic pressure supplied from the hydraulic pump and the load driven by the electric motor is provided, and the target engine speed is set. The setting means is a control system for a hybrid type construction machine, wherein the engine target speed is set according to the power consumption of the load measured by the load measuring means.
According to a fifth aspect of the present invention, in the fourth aspect, the engine target speed setting means corrects the engine target speed in accordance with a rate of change in power consumption of the load, and the engine target output setting means corrects the correction. A control system for a hybrid construction machine, wherein an engine target output is set based on an engine target speed.
According to a sixth aspect of the present invention, in any one of the first to fifth aspects, a charge amount detection unit that detects a charge amount of the power storage device is provided, and the control device drives the engine according to the charge amount of the power storage device. And a drive / stop switching means for performing stop switching control, and when the engine is stopped, a control command is output to the power transmission intermittent means for interrupting power transmission between the engine, the hydraulic pump and the generator motor. It is a control system in a hybrid type construction machine.
According to a seventh aspect of the present invention, in the sixth aspect, the drive / stop switching means has a high efficiency range in which the charge amount of the power storage device is preset as a range in which the charge / discharge capacity per unit time of the power storage device is large Thus, a control system in a hybrid construction machine is characterized in that engine switching control for driving and stopping is performed.

By setting the engine target output at which the engine efficiency is maximized in accordance with the engine target rotational speed, the engine is operated at the engine target rotational speed and the engine target output. Thus, the engine can always be operated efficiently, which can greatly contribute to the improvement of fuel consumption. In addition, this system calculates a generator / motor target output for setting the engine output to the engine target output based on the output of the hydraulic pump, and uses the generator / motor output as the generator / motor target output. Since the target output is configured, the engine output can be controlled to become the engine target output regardless of the output fluctuation of the hydraulic pump.
According to the invention of claim 2, even if an error occurs in the output measurement of the hydraulic pump, the error can be compensated by the output of the generator motor, so that the engine output can be surely set to the engine target output. it can.
According to the invention of claim 3, the engine target rotational speed is set according to the operation value of the engine rotational speed switching means for the operator to arbitrarily switch the engine rotational speed. The operator can arbitrarily switch the engine speed according to the work contents and work environment performed by the mold construction machine, and the engine is always operated efficiently even if the engine speed is switched. .
According to the invention of claim 4, the engine target rotational speed is set according to the power consumption of the load. Therefore, when the power consumption of the load is large, it corresponds to the large load. While the engine target speed and engine target output are set and work can be performed efficiently, when the power consumption of the load is small, the engine target speed and engine target output corresponding to the small load are set. Fuel consumption can be reduced, which can contribute to further improvement in fuel consumption.
According to the invention of claim 5, the engine target speed and the engine target output in which the load increase / decrease change is predicted are set, and thus the engine speed control capable of quickly responding to the load increase / decrease change, Output control can be performed.
According to the sixth aspect of the present invention, when charging of the power storage device is unnecessary, it is possible to reduce wasteful fuel consumption by stopping the engine. On the other hand, when the engine is driven, the engine is always operated with good engine efficiency. Will be.
According to the seventh aspect of the present invention, the power storage device can be operated in a high efficiency range, and the power storage device can also be highly efficient.

It is a side view of a hybrid type hydraulic excavator. It is a figure which shows the whole structure of the control system in 1st embodiment. It is a block diagram which shows the structure of the engine and generator motor control part in 1st embodiment. It is a flowchart figure which shows the control procedure of the engine and generator motor control part in 1st embodiment. It is a graph which shows a response | compatibility with an engine target rotational speed and an engine target output. It is a figure which shows the relationship between an engine output and a fuel consumption rate. It is a figure which shows the whole structure of the control system in 2nd embodiment. It is a block diagram which shows the structure of the engine and generator motor control part in 2nd embodiment. It is a flowchart figure which shows the control procedure of the engine and generator motor control part in 2nd embodiment. (A) is a graph showing the correspondence between the power consumption of the load and the target engine speed in the second embodiment, and (B) shows the case where the target engine speed is corrected according to the rate of change of the power consumption of the load. It is a graph to show.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the first embodiment will be described with reference to FIGS. 1 to 6. In FIG. 1, reference numeral 1 denotes a hybrid hydraulic excavator that is an example of a hybrid construction machine according to the present invention. 1 includes a crawler type lower traveling body 2, an upper revolving body 3 that is pivotably supported by the lower traveling body 2, a front work machine 4 that is mounted on the upper revolving body 3, and the like. The machine 4 is configured using a boom 5, an arm 6, a bucket 7, and the like. Further, the hybrid hydraulic excavator 1 includes a boom cylinder 8, an arm cylinder 9, a bucket cylinder 10, and left and right traveling motors 11L, 11R for traveling the lower traveling body 2 that swing the boom 5, arm 6, and bucket 7, respectively. The upper swing body 3 is equipped with an engine 12, a power storage device 13, a hydraulic pump 14, a generator motor 15 and the like as a power source.

  Next, the overall configuration of a control system for operating the hybrid excavator 1 will be described with reference to FIG. 2. The engine 12 is mechanically parallel to the hydraulic pump 14 and the generator motor 15 via the power transmission mechanism 16. It is connected.

  The engine 12 is controlled in its rotational speed (rotational speed) by adjusting the fuel injection amount by the engine controller 17, and the engine controller 17 is operated based on a control command output from a control device 18 described later. To control. The engine controller 17 corresponds to the engine control means of the present invention.

  The hydraulic pump 14 supplies hydraulic pressure to a hydraulic actuator A (in the present embodiment, the boom cylinder 8, the arm cylinder 9, the bucket cylinder 10, and the left and right traveling motors 11L and 11R) provided in the hybrid hydraulic excavator 1. A variable displacement pump serving as a source, and between the hydraulic pump 14 and each hydraulic actuator A, oil is supplied to the hydraulic actuator A based on the operation of an operation tool (not shown) for each hydraulic actuator A. A control valve 19 for performing exhaust control is provided. Reference numeral 14a denotes a capacity variable means of the hydraulic pump 14. The capacity variable means 14a controls the discharge flow rate of the hydraulic pump 14 based on the operation amount of the operation tool for the hydraulic actuator A and the discharge pressure of the hydraulic pump 14. Is configured to do. The hydraulic actuator A constitutes a load driven by pressure oil supply from the hydraulic pump of the present invention.

  The generator motor 15 has a function as a generator that generates power by being driven by the power of the engine 12 and a function as an electric motor that drives the hydraulic pump 14. The generator operation of the generator motor 15 and the switching of the motor operation are performed by the generator motor controller 20, and the generator motor controller 20 performs the power generation based on a control command from the control device 18 described later. Machine operation, motor operation switching control, power generation output control during generator operation, output or rotation speed or torque control during motor operation are performed. The generator motor controller 20 corresponds to the generator motor control means of the present invention.

  On the other hand, the power transmission mechanism 16 mechanically connects the engine 12, the hydraulic pump 14, and the generator motor 15 in parallel as described above. The power transmission mechanism 16 includes the engine 12, the hydraulic pump 14, A clutch mechanism 16 a is provided for intermittently connecting the generator motor 15 to the power transmission mechanism 16. The clutch mechanism 16 a intermittently connects the power transmission mechanism 16 to the engine 12, the hydraulic pump 14, and the generator motor 15 based on a control command from the control device 18 described later. The clutch mechanism 16a corresponds to the power transmission intermittent means of the present invention.

  Further, the generator motor 15 is connected to the motors 26 to 29 for turning, pilot pump, cooling fan, and sub pump via the generator motor controller 20, the bus 21 and the motor controllers 22 to 25. ing.

  The motor controllers 22 to 25 are based on a control command output from the control device 18 to be described later, and outputs, rotation speeds or torques of the motors 26 to 29 for turning, pilot pump, cooling fan, and sub pump. To control each. The motor controllers 22 to 25 correspond to the motor control means of the present invention.

  The turning electric motor 26 is a dedicated electric motor that drives the turning mechanism 31 of the upper turning body 3 via the turning speed reducer 30. The pilot pump electric motor 27 is a dedicated electric motor that drives a pilot pump 32 that is a hydraulic pressure supply source of the pilot pressure. The cooling fan motor 28 is a dedicated motor that drives a heat exchanger (not shown) such as a radiator or an oil cooler or a cooling fan 33 that supplies cooling air to the engine 12. The sub-pump motor 29 drives a sub-pump 34 which is a hydraulic supply source of a hydraulic actuator B (not shown, but a hydraulic actuator provided in a hybrid construction machine other than the hydraulic actuator A using the hydraulic pump 14 as a hydraulic supply source). It is a dedicated electric motor. And control of the output or rotation speed or torque of these electric motors 26-29 is comprised based on the control command output to the electric motor controllers 22-25 from the control apparatus 18 as mentioned above. . Here, in the present embodiment, the sub-pump 34 is a variable displacement pump provided with a displacement variable means 34 a, and the displacement variable means 34 a is based on a control command output from the control device 18. Thus, the capacity of the sub pump 34 is controlled. The pilot pump 32 is a constant capacity pump. The turning mechanism 31, the pilot pump 32, the cooling fan 33, and the sub pump 34 constitute a load driven by the electric motor of the present invention.

  Further, in FIG. 2, reference numeral 13 denotes a power storage device having a storage / discharge function such as a battery or a capacitor, and the power storage device 13 is connected to the bus 21 between the generator motor controller 20 and the motor controllers 22 to 25. As a result, power can be exchanged among the power storage device 13, the generator motor 15, and the motors 26 to 29. When the generator motor 15 is operating as a motor, the power storage device 13 supplies power to the generator motor 15 and the motors 26 to 29, while the generator motor 15 is operating as a generator. The electric power is stored and discharged according to the excess and deficiency between the output of the generator motor 15 and the outputs of the motors 26 to 29. In the present embodiment, the storage and discharge of the power storage device 13 is automatically performed by the difference between the voltage of the bus 21 and the voltage of the power storage device 13. That is, when the output of the generator motor 15 has a surplus with respect to the outputs of the motors 26 to 29, the voltage of the bus 21 becomes higher than the voltage of the power storage device 13, whereby the surplus power of the generator motor 15 is increased. On the other hand, when the output of the generator motor 15 is insufficient with respect to the outputs of the motors 26 to 29, the voltage of the bus 21 becomes lower than the voltage of the power storage device 13, thereby being discharged from the power storage device 13. Insufficient power is supplied to the motors 26-29.

  On the other hand, the control device 18 includes characteristics of the engine 12 (characteristics relating to engine efficiency, engine output, engine speed, engine no-load speed, etc.), and characteristics of the generator motor 15 (generator motor efficiency, generator motor output, generator motor). Characteristics regarding the rotational speed, excitation current, etc.) characteristics of the power storage device 13 (characteristics regarding capacity, efficiency, etc.), characteristics of the hydraulic pump 14 (characteristics regarding pump efficiency, pump volume, pump rotational speed, etc.), characteristics of the motors 26-29. (Characteristics related to motor efficiency, motor output, motor speed, motor torque, etc.), characteristics of sub pump 34 (characteristics related to pump efficiency, pump volume, pump speed, etc.), pilot set pressure (pressure of the discharge line of pilot pump 32) A memo that stores various data such as preset pressure) and data used for control, which will be described later 35 is provided. Then, the control device 18 determines the charge amount sensor (corresponding to the charge amount detection means of the present invention) 36 that detects the charge amount of the power storage device 13, the voltage sensor 37 that measures the voltage of the bus 21, and the rotational speed of the hydraulic pump 14. Pump rotation number detection sensor 38 to detect, pump capacity detection sensor 39 to detect the capacity of the hydraulic pump 14, pump discharge pressure detection sensor 40 to detect the discharge pressure of the hydraulic pump 14, hydraulic actuator A (boom cylinder 8, arm cylinder 9) , Bucket cylinder 10, left and right traveling motors 11 </ b> L, 11 </ b> R), turning, and hydraulic actuator B operating tools (not shown, but operating buttons, operating pedals, operating switches, etc.) are detected. (For example, a potentiometer that electrically detects the amount of operation of the operation tool, or a pi that is output based on operation of the operation tool. A pressure sensor for detecting the pressure of the engine pressure) 41, a signal from the rotation speed switching dial 42, and the like are input, and based on these input signals and data stored in the memory 35, the clutch mechanism 16a, the engine A control command is output to the controller 17, the generator motor controller 20, the motor controllers 22 to 25, the capacity variable means 34a of the sub pump 34, and the like.

  Here, the rotation speed switching dial 42 is an operating tool for the operator to arbitrarily switch the rotation speed of the engine 12, and corresponds to the engine rotation speed switching means of the present invention. In the present embodiment, the dial value D of the rotation speed switching dial 42 is provided in 10 stages of D1 to D10, with the highest engine speed at D10 and the lowest engine speed at D1. The dial value D of the rotation speed switching dial 42 corresponds to the operation value of the engine rotation speed switching means of the present invention.

  The control device 18 is provided with an engine / generator motor control unit 43 for controlling the engine 12 and the generator motor 15. The configuration of the engine / generator motor controller 43 is shown in the block diagram of FIG. The engine / generator motor control unit 43 is based on the memory 35, the charge amount sensor 36, the rotation speed switching dial 42, the pump rotation speed detection sensor 38, the pump capacity detection sensor 39, and the pump discharge pressure detection sensor on the input side. 40 is connected, and the clutch mechanism 16a, the engine controller 17, and the generator motor controller 20 are connected to the output side, and a drive / stop reference value setting unit 44, a drive / stop determination unit 45, and an engine target speed setting unit. 46, engine target output setting unit 47, pump output calculation unit 48, command value calculation unit 49, drive / stop switching unit 50 It is configured Te. Further, the command value calculation unit 49 includes an engine speed command value calculation unit 51, a generator motor output command value calculation unit 52, and a generator motor output command value calculation unit 53 when the engine is stopped. The engine target speed setting unit 46 constitutes an engine target speed setting unit of the present invention, and the engine target output setting unit 47 constitutes an engine target output setting unit of the present invention. The drive / stop reference value setting unit 44, the drive / stop determination unit 45, and the drive / stop switching unit 50 constitute drive / stop switching means of the present invention.

  Next, control of the engine 12 and the generator motor 15 performed by the engine / generator motor controller 43 will be described with reference to the block diagram of FIG. 3 and the flowchart of FIG. First, when the hybrid excavator 1 starts operation, the engine / generator motor controller 43 reads the data stored in the memory 35 (step S1).

  Next, the charge amount SOC of the power storage device 13 detected by the charge amount sensor 36, the rotation speed of the hydraulic pump 14 detected by the pump rotation speed detection sensor 38, the pump capacity detection sensor 39, and the pump discharge pressure detection sensor 40, respectively. The volume, the discharge pressure, and the dial value D of the rotation speed switching dial 42 are read (step S2).

  Next, the engine target speed setting unit 46 sets the engine target speed ωs (ωs1 to ωs10) according to the dial values D (D1 to D10) of the speed switching dial 42 (step S3).

  Further, the engine target output setting unit 47 uses the graph (shown in FIG. 5) showing the correspondence between the engine target rotation speed ωs and the engine target output Pes, and the engine target rotation speed setting unit 46 sets the engine target. An engine target output Pes (Pes1 to Pes10) corresponding to the rotational speed ωs (ωs1 to ωs10) is set (step S4). The engine target output Pes is an engine output at which the engine efficiency is maximized when the engine 12 is at the engine target speed ωs. As shown in FIG. 5, the engine target speed ωs increases as the engine target speed ωs increases. The output Pes also increases. A graph showing the correspondence between the engine target speed ωs and the engine target output Pes is stored in the memory 35 as data.

  Here, an example of the characteristics of the engine 12 mounted on the hybrid construction machine will be described with reference to FIG. The solid line shown in FIG. 6 is a graph showing the relationship between the engine output and the fuel consumption rate when the maximum output is set to a no-load rotational speed that can be output, and the engine output is in a very low range (close to a no-load state). Excluding the (state), the fuel consumption rate is minimized at the point A where the maximum output is achieved (the engine efficiency is maximized). Further, the points B1 to B9 on the dotted line L shown in FIG. 6 have a minimum fuel consumption rate (engine efficiency) when the no-load speed is set lower than the no-load speed capable of outputting the maximum output. These points B1 to B9 have a lower engine output than the point A but a higher engine efficiency. In the case of such engine characteristics, the engine speed and engine output at point A are set as the engine target speed ωs10 and engine target output Pes10 when the dial value D10 of the speed switching dial 42 is set. Further, the engine speed and engine output at the points B1 to B9 are set as engine target speeds ωs1 to ωs9 and engine target outputs Pes1 to Pes9 when the dial values D1 to D9 of the speed change dial 42 are set. . Alternatively, in order to prevent engine stall, the points whose outputs are slightly lower than the points B1 to B9 and the point A are set as engine target outputs Pes1 to Pes10 when the rotation speed switching dial 42 has dial values D1 to D10. In this way, when the engine target output Pes is set at a point where the output is slightly lowered to prevent engine stall, strictly speaking, the engine efficiency is slightly lowered, but in this case, the engine efficiency within the range where engine stall can be prevented. Is included in the engine target output Pes that maximizes the engine efficiency of the present invention.

  Further, after setting the engine target speed ωs and the engine target output Pes in the steps S3 and S4, the drive / stop reference value setting unit 44 sets a reference value for switching the drive / stop of the engine 12 (step S5). That is, engine 12 is controlled to be switched between driving and stopping according to the amount of charge of power storage device 13 as will be described later, but the amount of charge of power storage device 13 used when driving engine 12 is set to drive reference value SOC1. And the charge amount of the power storage device 13 used when the engine 12 is stopped is set as the stop reference value SOC2. The stop reference value SOC2 is set to a value larger than the drive reference value SOC1 (SOC1 <SOC2).

  Here, in setting the reference value, in the present embodiment, the charge amount SOC of the power storage device 13 is set in advance as a range where the charge / discharge capacity per unit time of the power storage device 13 is large. The drive reference value SOC1 and the stop reference value SOC2 are set so that. In this case, when the charge amount when the efficiency of the power storage device 13 is maximum (the charge / discharge capacity per unit time is maximum) is SOCx, the drive / stop reference value setting unit 44 sets the SOCx as the median value. A range from minus α (−α) to plus α (+ α) ((SOCx−α) to (SOCx + α)) is set as a high efficiency range, and a minimum value (SOCx−α) of the high efficiency range is set as a drive reference value. It is set as SOC1, and the maximum value (SOCx + α) in the high efficiency range is set as the stop reference value SOC2. For example, the charge amount when the efficiency of the power storage device 13 is maximum is 50% (percentage when the upper limit value of the charge amount of the power storage device 13 is 100% and the lower limit value is 0%. The same applies hereinafter), and α is 10% In this case, the range of 40% to 60% charge is set as the high efficiency range, 40% charge is set as the drive reference value SOC1, and 60% charge is set as the stop reference value SOC2.

  Further, after setting the drive reference value SOC1 and the stop reference value SOC2 in step S5, the drive / stop determination unit 45 detects the charge amount SOC of the power storage device 13 detected by the charge amount sensor 36 and the drive reference value SOC1, The stop reference value SOC2 is compared to determine whether to drive / stop the engine 12 (step S6). In this case, the drive / stop determination unit 45 determines that the engine 12 is to be driven when the charge amount SOC of the power storage device 13 detected by the charge amount sensor 36 is smaller than the drive reference value SOC1 (SOC <SOC1). Further, when charge amount SOC becomes larger than stop reference value SOC2 (SOC> SOC2), it is determined that engine 12 is to be stopped. Further, when the charge amount SOC is not less than the drive reference value SOC1 and not more than the stop reference value SOC2 (SOC1 ≦ SOC ≦ SOC2), it is determined that the drive is continued if the engine 12 is being driven, and the engine 12 is stopped. If it is, it is determined that the stop is continued. Then, as described later, by switching driving / stopping of the engine 12 based on the above determination, the amount of power stored in the power storage device 13 is between the drive reference value SOC1 and the stop reference value SOC2, that is, in a high efficiency range. To be controlled.

Further, the pump output calculator 48 calculates the output Pp of the hydraulic pump 14 (step S7). The calculation of the output Pp of the hydraulic pump 14 is performed using the following equation (1).
Pp = ωp × v × pr (1)
In the above formula (1), ωp is the rotational speed of the hydraulic pump 14 detected by the pump rotational speed detection sensor 38, v is the capacity of the hydraulic pump 14 detected by the pump capacity detection sensor 39, and pr is a pump discharge pressure detection sensor. This is the discharge pressure of the hydraulic pump 14 detected by 40. In the present embodiment, the pump rotation speed detection sensor 38, the pump displacement detection sensor 39, and the pump discharge pressure detection sensor 40 constitute the pump output measuring means of the present invention.

  Further, in the engine speed command value calculation unit 51, the generator motor output command value calculation unit 52, and the engine stop time generator motor output command value calculation unit 53, the engine speed command value ωc, the generator motor output command value Pgc, and the engine stop time The generator motor output command value Pgct is calculated (step S8). The engine speed command value ωc is a command value output to the engine controller 17 in order to set the engine speed of the engine 12 to the engine target speed ωs. The generator motor output command value Pgc is output to the generator motor controller 20 to control the output of the generator motor 15 based on the output of the hydraulic pump 14 in order to set the output of the engine 12 to the engine target output Pes. It is a command value. That is, by controlling the output of the generator motor 15 based on the output of the hydraulic pump 14, the load applied to the engine 12 from the generator motor 15 and the hydraulic pump 14 is controlled to be constant. It is configured to control so that the engine target output Pes. The engine stop generator motor output command value Pgct is a command value that is output to the generator motor controller 20 when the hydraulic pump 14 is driven by the power of only the generator motor 15 when the engine 12 is stopped.

The engine speed command value calculation unit 51 uses a function (ωc = F (ωs)) indicating the relationship between the engine target speed ωs and the engine speed command value ωc stored as data in the memory 35. When the engine output is the engine target output Pes, an engine speed command value ωc for setting the engine speed to the engine target speed ωs is calculated.
Here, in the present embodiment, the engine controller 17 is configured to control the rotational speed of the engine 12 using the set value of the no-load rotational speed of the engine 12 as a command value. Is set to the engine speed command value ωc. In this case, the engine speed command value ωc (the set value of the no-load speed) is calculated using the following equation (2). When the output is the engine target output Pes, the engine speed command value ωc at which the engine speed becomes the engine target speed ωs can be obtained.
ωc = A × ωs + B (2)
In the above formula (2), A and B are constants determined by the characteristics of the engine 12.

On the other hand, the generator motor output command value calculation unit 52 calculates a generator motor target output Pgs for setting the output of the engine 12 to the engine target output Pes using the following equation (3). In the present embodiment, the generator motor controller 20 has a function of controlling the output of the generator motor 15 using the generator motor target output Pgs as a command value, and thus the generator motor target output Pgs remains as it is. It becomes the generator motor output command value Pgc.
Pgc = Pgs = (Pes−Pp / ηp) × ηg (3)
In the above equation (3), Pp is the output of the hydraulic pump 14 calculated in the pump output calculation unit 48, ηp is the efficiency of the hydraulic pump 14, ηg is the efficiency of the generator motor 15, and these values are stored in the memory 35. However, the hydraulic pump efficiency ηp and the generator motor efficiency ηg vary depending on the output and the rotational speed of the hydraulic pump 14 and the generator motor 15. The generator motor output command value Pgc is a command to operate the generator motor 15 as a generator when plus (Pgc ≧ 0), and a command to operate as a motor when minus (Pgc <0). .

Further, the engine stop generator motor output command value calculation unit 53 has a target output Pgst of the generator motor 15 when the engine 12 is stopped (hereinafter referred to as a generator motor target output Pgst when the engine is stopped). The output Pgst is not included in the generator motor target output of the present invention) using the following equation (4). The engine stop generator motor target output Pgst is directly used as the engine stop generator motor output command value Pgct.
Pgct = Pgst = (− Pp / ηp) × ηg (4)
In the above formula (4), Pp is the output of the hydraulic pump 14 calculated in the pump output calculation unit 48, ηp is the efficiency of the hydraulic pump 14, and ηg is the efficiency of the generator motor 15. Further, the generator motor output command value Pgct when the engine is stopped is negative (Pgct <0), and is a command for operating the generator motor 15 as a motor.

  Further, after the calculation of the engine speed command value ωc, the generator motor output command value Pgc, and the engine stop time generator motor output command value Pgct in step S8, the drive / stop switching unit 50 determines the drive / stop determination unit 45. However, it is determined whether the engine 12 is driven (including continuing driving) or stopped (including continuing stopping) (step S9).

  If it is determined in step S9 that the engine 12 is driven, the drive / stop switching unit 50 connects the engine 12, the hydraulic pump 14, and the generator motor 15 to the crack mechanism 16a of the power transmission mechanism 16. In addition, the control command is output, the engine speed command value ωc is output to the engine controller 17, and the generator motor output command value Pgc is output to the generator motor controller 20 (step S10). Thereby, the output of the generator motor 15 is controlled to become the generator motor target output Pgs. In this case, as described above, when the generator motor output command value Pgc is positive (Pgc ≧ 0), the generator motor 15 is controlled. Is output as a generator, and when the generator motor output command value Pgc is negative (Pgc <0), a control command for operating as a motor is output. And when the generator motor 15 is operating as a generator, the engine 12 bears the output of the generator motor 15 and the hydraulic pump 14, and when the generator motor 15 is operating as a motor, Although the output of the hydraulic pump 14 is borne by the engine 12 and the generator motor 15, in any case, the output of the generator motor 15 is controlled to become the generator motor target output Pgs based on the output of the hydraulic pump 14. Thus, the output of the engine 12 is controlled so as to be the engine target output Pes, and the rotational speed of the engine 12 is controlled so as to be the engine target rotational speed ωs. After step S10, the process returns to step S2.

  On the other hand, when it is determined in step S9 that the engine 12 is stopped, the drive / stop switching unit 50 disconnects the engine 12 from the hydraulic pump 14 and the generator motor 15 with respect to the clutch mechanism 16a of the power transmission mechanism 16, In addition, a control command is output so that the hydraulic pump 14 and the generator motor 15 are connected, and further, a stop command (engine speed command value ωc = 0) of the engine 12 is output to the engine controller 17, and power generation The engine stop generator motor output command value Pgct is output to the motor controller 20 (step S11). As a result, the engine 12 is stopped and the output of the generator motor 15 is controlled to be the generator motor output command value Pgct when the engine is stopped. The generator motor output command value Pgct when the engine is stopped is as described above. The hydraulic pump 14 is driven by the generator motor 15 that operates as an electric motor. After step S11, the process returns to step S2.

  Thus, by the control performed by the engine / generator motor control unit 43, the engine 12 is controlled to be driven / stopped so that the charge amount SOC of the power storage device 13 is in a high efficiency range. During driving, the rotational speed of the engine 12 is controlled so as to be the engine target rotational speed ωs set according to the dial value D of the rotational speed switching dial 42, and the output of the engine 12 is the engine target rotational speed ωs. At this time, the engine efficiency is controlled so as to be the engine target output Pes that maximizes the engine efficiency.

  Further, as described above, the control device 18 also outputs a control command to the motor controllers 22 to 25 and the capacity variable means 34a of the sub pump 34. In this case, the motor control for controlling the turning motor 26 is performed. A control command is output to the device 22 to drive the turning mechanism 31 at a speed corresponding to the operation amount of the turning operation tool. In addition, a control command is output to the motor controller 23 that controls the pilot pump motor 27 so that the discharge pressure of the pilot pump 32 is set to a preset pilot set pressure. Further, a control command is output to the motor controller 24 that controls the cooling fan motor 28 so that the cooling fan 33 can supply the necessary cooling air. Further, for the motor controller 25 that controls the sub-pump motor 29 and the capacity variable means 34a of the sub-pump 34, the discharge flow rate of the sub-pump 34 is the operation amount of the hydraulic actuator B operating tool that uses the sub-pump 34 as a hydraulic source. A control command is output to obtain a flow rate required according to

  Here, as described above, the control device 18 controls the discharge flow rate of the sub-pump 34 with respect to the motor controller 25 that controls the sub-pump motor 29 and the capacity variable means 34a of the sub-pump 34. A control command is output to obtain a flow rate corresponding to the amount. In this case, the sub-pump motor is set so that the total efficiency (motor efficiency ηm × pump efficiency ηp) of the sub-pump motor 29 and the sub-pump 34 is maximized. The number of revolutions 29 and the capacity of the sub pump 34 are controlled. That is, the flow rate of the sub-pump 34 is determined by the product of the rotation speed and the capacity of the sub-pump 34. The rotation speed of the sub-pump 34 is determined by the rotation speed of the sub-pump motor 29, and the rotation speed of the sub-pump motor 29 is controlled by the motor. The rotation speed of the sub pump motor 29 can be controlled by the rotation speed command value output to the compressor 25, and the displacement of the sub pump 34 can be controlled by the displacement command value output to the displacement variable means 34a. And the capacity of the sub pump 34 can be controlled so that the total efficiency (motor efficiency ηm × pump efficiency ηp) of the sub pump motor 29 and the sub pump 34 is maximized. As a result, the sub-pump motor 29 and the sub-pump 34 can be operated in a state where the total efficiency is maximized. The relationship between the rotation speed of the sub-pump motor 29 and the motor efficiency ηm and the relationship between the capacity of the sub-pump 34 and the pump efficiency ηp are stored as data in the memory 35.

  In the first embodiment configured as described, the hybrid excavator 1 includes an engine 12, a hydraulic pump 14, a hydraulic actuator A driven by pressure oil supplied from the hydraulic pump 14, and a generator. And a generator motor 15 that functions as an electric motor, a power transmission mechanism 16 that mechanically connects the engine 12, the hydraulic pump 14, and the generator motor 15 in parallel, a turning mechanism 31, a pilot pump 32, a cooling fan 33, and a sub pump 34. Each of the electric motors 26 to 29 to be driven and the power storage device 13 having a storage / discharge function is provided, and the power generator 21, the motors 26 to 29, and the power storage device 13 can transmit and receive electric power between them. In addition, the hybrid hydraulic excavator 1 further includes a rotation of the engine 12. The engine controller 17 for controlling the motor, the generator motor controller 20 for controlling the output of the generator motor 15, the motor controllers 22 to 25 for controlling the output, the rotational speed or the torque of the motors 26 to 29, respectively, and the power The clutch mechanism 16a for intermittently transmitting power by the transmission mechanism 16, the engine controller 17, the generator motor controller 20, the motor controllers 22 to 25, the control device 18 for outputting a control command to the clutch mechanism 16a, and the operator rotating the engine A rotational speed switching dial 42 for arbitrarily switching the number, and pump output measuring means (a pump rotational speed detection sensor 38, a pump capacity detection sensor 39, a pump discharge pressure detection sensor 40) for measuring the output of the hydraulic pump 14. Is provided. Then, the control device 18 sets the engine target speed ωs according to the dial value D of the speed switching dial 42, and the engine efficiency becomes maximum when the engine speed is the engine target speed ωs. The engine output is set as the engine target output Pes, and when the engine 12 is driven, a control command is output to the engine controller 17 so as to set the engine speed to the engine target speed ωs, which is measured by the pump output measuring means. Based on the output of the hydraulic pump 14, the generator motor target output Pgs for making the engine output the engine target output Pes is calculated, and the generator motor controller 20 is set so that the output of the generator motor 15 becomes the generator motor target output Pgs. Will output a control command.

  As a result, the engine 12 is set with the engine target speed ωs according to the dial value D of the speed switching dial 42, and further with the engine target output Pes with which the engine efficiency is maximized according to the engine target speed ωs. At the same time, the engine is operated at the target engine speed ωs and the target engine output Pes. Therefore, the engine 12 can always be operated efficiently, which can greatly contribute to the improvement of fuel consumption. Moreover, this calculates a generator motor target output Pgs for setting the output of the engine 12 to the engine target output Pes based on the output of the hydraulic pump 14 so that the output of the generator motor 15 becomes the generator motor target output Pgs. By controlling the engine output to the engine target output Pes, the engine output can be controlled to ensure the engine target output Pes regardless of the output fluctuation of the hydraulic pump 14. .

  Moreover, the engine target speed ωs is set according to the dial value D of the speed change dial 42 for the operator to arbitrarily switch the engine speed, so that the work content and work environment performed by the hybrid hydraulic excavator 1 are set. According to the above, the operator can arbitrarily switch the rotational speed of the engine 12, and even if the engine rotational speed is switched, the engine 12 is always operated in an efficient state.

  Further, in this device, a charge amount sensor 36 for detecting the charge amount of the power storage device 13 is provided, and the control device 18 performs switching control of driving and stopping of the engine 12 according to the charge amount of the power storage device 13. Drive / stop switching means (drive / stop reference value setting unit 44, drive / stop determination unit 45, drive / stop switching unit 50) is provided, and when the engine 12 is stopped, the engine 12, the hydraulic pump 14, and the generator motor Therefore, a control command is output to the clutch mechanism 16a of the power transmission mechanism 16 to cut off the power transmission to the power transmission mechanism 16. Thus, when charging of the power storage device 13 is not required, useless fuel consumption can be reduced by stopping the engine 12, while the engine 12 is always operated with good engine efficiency. Become.

  In addition, the drive / stop switching means is configured so that the charge amount of the power storage device 13 is in a high efficiency range that is preset as a range in which the charge / discharge capacity per unit time of the power storage device 13 is large. Drive and stop are switched. As a result, the power storage device 13 can be operated in a high efficiency range, and the power storage device 13 can also be highly efficient.

  The hybrid excavator 1 is provided with a sub-pump 34 that is not mechanically connected to the engine 12 and a sub-pump electric motor 29 that drives the sub-pump 34. A control command is output to the capacity variable means 34a to control the capacity of the sub pump 34, and a control command is output to the motor controller 25 to control the rotation speed of the sub pump motor 29, thereby controlling the discharge flow rate of the sub pump 34. In this case, the rotational speed of the sub-pump motor 29 and the capacity of the sub-pump 34 are set so that the total efficiency (motor efficiency ηm × pump efficiency ηp) of the sub-pump motor 29 and the sub-pump 34 is maximized. To control. Thus, the sub-pump electric motor 29 and the sub-pump 34 can be operated in a state where the total efficiency is maximized, which can greatly contribute to the high efficiency of the entire hybrid construction machine.

Next, a second embodiment of the present invention will be described with reference to FIGS. 1, 5, and 6 are the same as those in the first embodiment. In addition, the same reference numerals are attached to the same (same) as those in the first embodiment, and the details thereof are omitted.
First, FIG. 7 shows the overall configuration of the control system of the second embodiment. In FIG. 7, 56 is a power storage device current sensor that detects the storage / discharge current of the power storage device 13, and 57 is the second embodiment. It is an engine and generator motor control part provided in the control apparatus 18 of a form. Further, 58 is a memory provided in the control device 18 of the second embodiment, and in the memory 58, the characteristics of the engine 12, the characteristics of the generator motor 15, the power storage, as in the first embodiment. Various data such as the characteristics of the device 13, the characteristics of the hydraulic pump 14, the characteristics of the electric motors 26 to 29, the characteristics of the sub-pump 34, the pilot set pressure, data used for control described later, and the like are stored. In FIG. 7, the engine 12, the engine controller 17, the hydraulic pump 14, the capacity varying means 14a of the hydraulic pump 14, the control valve 19, the hydraulic actuator A, the generator motor 15, the generator motor controller 20, the power transmission mechanism 16, the clutch Mechanism 16a, power storage device 13, bus 21, motor controllers 22 to 25, motors 26 to 29 for turning, pilot pump, cooling fan, and sub pump, turning speed reducer 30, turning mechanism 31, pilot pump 32, About the cooling fan 33, the sub pump 34, the capacity variable means 34a of the sub pump 34, the charge amount sensor 36, the voltage sensor 37, the pump rotation speed detection sensor 38, the pump capacity detection sensor 39, the pump discharge pressure detection sensor 40, and the operation detection means 41 , Common to the first embodiment (the same ) Is therefore, description thereof will be omitted. In the second embodiment, the engine speed switching means that is arbitrarily operated by the operator is not provided like the speed switching dial 42 of the first embodiment.

  Next, the configuration of the engine / generator motor control unit 57 provided in the control device 18 of the second embodiment will be described with reference to the block diagram of FIG. A memory 58, a charge amount sensor 36, a voltage sensor 37, a power storage device current sensor 56, a pump rotation speed detection sensor 38, a pump capacity detection sensor 39, and a pump discharge pressure detection sensor 40 are connected to the clutch mechanism 16a, The engine controller 17 and the generator motor controller 20 are connected, and a drive / stop reference value setting unit 44, a drive / stop determination unit 45, a load calculation unit 59, an engine target rotation speed setting unit 60, and an engine target output setting unit 61. , A pump output calculation unit 48, a command value calculation unit 49, and a drive / stop switching unit 50. Further, the command value calculation unit 49 includes an engine speed command value calculation unit 51, a generator motor output command value calculation unit 52, and a generator motor output command value calculation unit 53 when the engine is stopped. The drive / stop reference value setting unit 44, drive / stop determination unit 45, pump output calculation unit 48, command value calculation unit 49 (engine speed command value calculation unit 51, generator motor output command value calculation unit 52, engine The stop generator motor output command value calculation unit 53) and the drive / stop switching unit 50 perform the same control as in the first embodiment. The control of the load calculation unit 59, the engine target speed setting unit 60, and the engine target output setting unit 61 will be described later. The engine target speed setting unit 60 constitutes the engine target speed setting means of the present invention. The engine target output setting unit 61 constitutes engine target output setting means of the present invention.

  Further, the control of the engine 12 and the generator motor 15 performed by the engine / generator motor controller 57 will be described with reference to the block diagram of FIG. 8 and the flowchart of FIG. First, when the hybrid hydraulic excavator 1 starts operation, the engine / generator motor controller 57 reads data stored in the memory 58 (step S21).

  Next, the charge amount SOC of the power storage device 13 detected by the charge amount sensor 36, the voltage of the bus 21 detected by the voltage sensor 37, the pump rotation speed detection sensor 38, the pump capacity detection sensor 39, and the pump discharge pressure detection sensor The rotational speed, capacity, and discharge pressure of the hydraulic pump 14 detected by 40, and the storage / discharge current of the power storage device 13 detected by the power storage device current sensor 56 are read (step S22).

  Next, the pump output calculator 48 calculates the output Pp of the hydraulic pump 14 (step S23). Since the calculation of the output Pp of the hydraulic pump 14 is the same as the calculation of the output Pp of the hydraulic pump 14 in the pump output calculation unit 48 of the first embodiment, a description thereof will be omitted, but the equation (1) ), And a pump rotation speed detection sensor 38, a pump displacement detection sensor 39, and a pump discharge pressure detection sensor 40 that respectively detect the rotation speed, capacity, and discharge pressure of the hydraulic pump 14 used for the calculation of the equation (1). Constitutes the pump output measuring means of the present invention.

Next, the load calculator 59 is driven by a load (hydraulic actuator A) driven by supply of pressure oil from the hydraulic pump 14 and by motors 26 to 29 for turning, pilot pump, cooling fan, and sub pump. The power Pf (load power consumption Pf) consumed by the load (swivel mechanism 31, pilot pump 32, cooling fan 33, sub pump 34) is calculated (step S24). In this case, in the present embodiment, as shown in the following equation (5), the sum of the output Pp of the hydraulic pump 14, the output Pg of the generator motor 15, and the stored / discharged power Pb of the power storage device 13 is calculated as load consumption. Calculated as power Pf. In this case, the output Pp of the hydraulic pump 14 corresponds to the power consumption of a load driven by the supply of pressure oil from the hydraulic pump 14, and the output Pg of the generator motor 15 and the stored / discharged power Pb of the power storage device 13. Is equivalent to the power consumption of the load driven by the electric motors 26-29.
Pf = Pp + Pg + Pb (5)
Here, as the output Pp of the hydraulic pump 14 in the above formula (5), the value of the output Pp of the hydraulic pump 14 calculated by the pump output calculation unit 48 is used. Further, as the output Pg of the generator motor 15, the generator motor output command value Pgc output from the control device 18 to the generator motor controller 20 is used. The generator motor output command value Pgc will be described later, but becomes positive (Pgc ≧ 0) when the generator motor 15 operates as a generator, and becomes negative (Pgc <0) when operated as a motor. When the generator motor output command value Pgc is not output at the time of initial operation or the like, the output Pg of the generator motor 15 is set to zero (Pg = 0). Furthermore, the stored / discharged power Pb of the power storage device 13 is calculated using the following equation (6).
Pb = Ib × V (6)
In the above formula (6), V is the voltage of the bus 21 detected by the voltage sensor 37, Ib is the storage / discharge current of the power storage device 13 detected by the power storage device current sensor 56, and the storage / discharge of the power storage device 13 The current is a plus sign when the power storage device 13 is discharged, and a minus sign when the power storage device 13 is storing power. The voltage sensor 37 and the power storage device current sensor 56 constitute load measuring means of the present invention. In addition, as described above, the calculation of the output Pp of the hydraulic pump 14 includes the rotation speed, capacity, and displacement of the hydraulic pump 14 detected by the pump rotation speed detection sensor 38, the pump capacity detection sensor 39, and the pump discharge pressure detection sensor 40. Although the discharge pressure is used, the pump rotation speed detection sensor 38, the pump displacement detection sensor 39, and the pump discharge pressure detection sensor 40 also constitute load measuring means of the present invention.

  Next, the engine target speed setting unit 60 calculates the target engine speed ωs corresponding to the power consumption Pf of the load by using the graph (shown in FIG. 10A), which is calculated by the load calculation unit 59. The engine target speed ωs is set in accordance with the consumed power Pf of the load (step S25). In this case, as shown in FIG. 10A, the target engine speed ωs is set higher as the power consumption Pf of the load increases. A graph showing the correspondence between the power consumption Pf of the load and the target engine speed ωs is created based on the characteristics of the engine 12 and stored as data in the memory 58. The rotation speed ωs can be stepless as shown by a solid line in FIG. 10A, or can be in a plurality of stages as shown by a dotted line in FIG.

Further, the engine target output setting unit 61 uses the graph showing the correspondence between the engine target rotation speed ωs and the engine target output Pes to correspond to the engine target rotation speed ωs set by the engine target rotation speed setting unit 60. An engine target output Pes is set (step S26). The engine target output Pes is the engine output at which the engine efficiency is maximized when the engine 12 is at the engine target speed ωs, and the engine target output Pes increases as the engine target speed ωs increases. A graph indicating the correspondence between the engine target speed ωs and the engine target output Pes is stored in the memory 58 as data.
The engine target speed ωs and the engine target output Pes are set according to the characteristics of the engine 12, but in the case of the engine characteristics as shown in FIG. 6, the engine target speed ωs and the engine target output are set. The output Pes is set so as to be positioned on the point A and the dotted line L in FIG. In this case, the graph showing the correspondence between the engine target speed ωs and the engine target output Pes is the same as the graph (FIG. 5) used in the first embodiment described above.

  Further, after the engine target speed ωs and the engine target output Pes are set in steps S25 and S26, the control in steps S27, S28, S29, S30, S31, and S32 is performed. Since the control in steps S27, S28, S29, S30, S31, and S32 is the same as the control in steps S5, S6, S8, S9, S10, and S11 in the first embodiment described above, description thereof is omitted. However, by the control performed by the engine / generator motor control unit 47, the engine 12 is controlled to be switched between driving and stopping so that the charge amount SOC of the power storage device 13 is in the high efficiency range, and at the time of driving the engine 12 The rotational speed of the engine 12 is controlled so as to be the engine target rotational speed ωs set according to the power Pf consumed by the load, and the output of the engine 12 has the engine efficiency when the engine target rotational speed ωs. It is configured to be controlled so that the engine target output Pes is maximized.

  In the second embodiment configured as described above, the engine 12 has an engine target speed ωs set according to the power Pf consumed by the load, and the engine efficiency according to the engine target speed ωs. Is set at the engine target output Pes, and is operated at the engine target rotational speed ωs and the engine target output Pes. Thus, as in the first embodiment, the engine 12 can always be operated efficiently, which can greatly contribute to the improvement of fuel consumption.

  Moreover, in the second embodiment, the engine target speed ωs is set according to the power Pf consumed by the load. Therefore, when the power consumption Pf of the load is large, the large load can be handled. The engine target speed ωs and the engine target output Pes to be set are set so that the work can be performed efficiently. On the other hand, when the power consumption Pf of the load is small, the engine target speed ωs corresponding to the small load, the engine By setting the target output Pes, it is possible to reduce fuel consumption and contribute to further improvement in fuel consumption.

Needless to say, the present invention is not limited to the first and second embodiments described above. For example, a generator motor for setting the output of the engine 12 to the engine target output Pes based on the output of the hydraulic pump 14. In calculating the target output Pgs, a deviation (ωs−ωa) between the engine target speed ωs and the actual engine speed ωa is obtained, and the generator motor target output Pgs is set such that the deviation is eliminated (becomes “0”). It can also be configured to increase or decrease. The control method in this case is PI control, and the generator motor target output Pgs is calculated using the following equation (7).
Pgs = (Pes−Pp / ηp) × ηg + (Kp + Ki / s) (ωs−ωa) (7)
In the above equation (7), Pp is the output of the hydraulic pump 14 calculated in the pump output calculation unit 48, ηp is the efficiency of the hydraulic pump 14, ηg is the efficiency of the generator motor 15, Kp is a proportionality constant, Ki is an integration constant, s is a Laplace operator.
Then, the output of the generator motor target output Pgs is increased or decreased so as to eliminate the deviation (ωs−ωa) between the engine target speed ωs and the actual engine speed ωa, thereby measuring the output of the hydraulic pump 14 and calculating the efficiency. (In general, the load fluctuation during the work of the construction machine is large, and therefore there is a possibility that the measurement error of the output of the hydraulic pump 14 and the calculation error of the efficiency may be large). Can be compensated for by the output of the generator motor 15, so that the output of the engine 12 can be reliably set to the engine target output Pes. The actual engine speed ωa is the actual engine speed detected by the engine speed sensor.

  In the first embodiment, the engine speed switching means 42 is provided as an engine speed switching means for the operator to arbitrarily switch the engine speed, and the dial value of the engine speed switching dial 42 is used as the dial value. Although 10 stages D1 to D10 are provided, the number of stages is not limited as long as a plurality of dial values are provided, and further, there may be no stages. Further, the engine speed switching means is not limited to the dial type, and any appropriate means such as a lever type or a method using an operation screen and operation keys of the monitor device can be adopted.

  Furthermore, in the first embodiment, the engine target speed ωs is set according to the operation value of the engine speed switching means, and the engine target output Pes is set according to the engine target speed ωs. However, in this configuration, the maximum output of the hydraulic pump 14 can be further limited in accordance with the operation value of the engine speed switching means. In this case, since the engine target output and the maximum output of the hydraulic pump 14 are both set according to the operation value of the engine speed switching means, the output of the hydraulic pump 14 becomes excessive with respect to the output of the engine. Can be avoided. In this case, the control device 18 outputs a control command for limiting the maximum output of the hydraulic pump 14 to the displacement variable means 14a of the hydraulic pump 14 in accordance with the operation value of the engine speed switching means. It will be.

  In the first and second embodiments, as pump output measuring means for measuring the output of the hydraulic pump, a pump rotational speed detection sensor for detecting the rotational speed, capacity, and discharge pressure of the hydraulic pump, and pump capacity, respectively. Although a detection sensor and a pump discharge pressure detection sensor are provided, for example, a pump flow rate detection sensor that detects the flow rate of the hydraulic pump is provided instead of the pump rotation speed detection sensor and the pump capacity detection sensor. May be. Further, the capacity of the hydraulic pump can be configured to be variable based on a control command from the control device, but in this case, the pump capacity output from the control device is not provided without providing a pump capacity detection sensor. The displacement of the hydraulic pump can be obtained based on the command value.

  Furthermore, in the second embodiment, the engine target speed ωs is set corresponding to the load power consumption Pf. In this case, the rate of change PfR (= ΔPf / sec () of the load power consumption Pf is set. It is also possible to correct the value of the engine target speed ωs according to the amount of change in load power consumption Pf per unit time)). In this case, the load calculation unit 59 calculates the power consumption Pf of the load and calculates the rate of change PfR of the power consumption Pf of the load. Further, when the absolute value of the rate of change PfR of the load power consumption Pf is smaller than the preset value S (| PfR | <S), the engine target speed setting unit 60 performs the second implementation described above. As in the case of the embodiment, the target engine speed ωs corresponding to the power consumption Pf of the load is obtained using the graph shown by the solid line in FIG. 10B (the same as the graph shown by the solid line in FIG. 10A). On the other hand, when the absolute value of the rate of change PfR of the power consumption Pf of the load is equal to or larger than the set value S (| PfR | ≧ S), when the power consumption Pf increases (rate of change PfR> 0), As indicated by the alternate long and short dash line in FIG. 10 (B), the engine target rotational speed ωs is corrected so as to increase, and when the power consumption Pf decreases (change rate PfR <0), two points are shown in FIG. As indicated by the chain line, the target engine speed ωs should be lowered. To. The correction value in this case may be a constant value set in advance, but may be increased or decreased according to the rate of change. Further, the engine target output setting unit 61 sets the engine target output Pes based on the corrected engine target speed ωs. In this way, the value of the engine target speed ωs is corrected according to the rate of change PfR (= ΔPf / sec) of the power consumption Pf of the load, and the engine target output Pes is based on the corrected engine target speed ωs. The engine target speed ωs and the engine target output Pes for which the load increase / decrease change is predicted are set, and the engine speed control and the output control capable of quickly responding to the load increase / decrease change are performed. Can do. In FIG. 10B, the case where the engine target speed ωs is set steplessly with respect to the power consumption Pf of the load is illustrated, but the same applies when the engine target speed ωs is set stepwise. Of course, it can be corrected.

In the second embodiment, the output Pg of the generator motor 15 and the stored / discharged power Pb of the power storage device 13 are summed to obtain the power consumption of the load driven by the motor. The stored / discharged power Pb is calculated based on detection signals from the voltage sensor 37 and the power storage device current sensor 56. However, the present invention is not limited to this, and the power consumption of the load is obtained using other appropriate means. You can also. For example, the stored / discharged power of the power storage device 13 can be obtained based on the rate of change of the charge amount of the power storage device 13 (storage / discharge power = coefficient × charge amount change rate, the coefficient is determined by the characteristics of the power storage device 13). It is also possible to obtain the power supply Pmi supplied to each electric motor and use the sum (ΣPmi) of these as the power consumption of the load driven by the electric motor. In this case, when the output command value is output from the control device 18 to the electric motor, the supply power Pmi to the electric motor can be obtained from the output command value. Further, when the rotation speed command value or the torque command value is output from the control device 18 to the electric motor, the electric power Pmi supplied to the electric motor can be obtained using the following equation (8).
Pmi = ωm × Tm / ηm (8)
In the above equation (8), ωm is the rotational speed command value or the rotational speed of the motor detected by the rotational speed detection sensor, Tm is the torque command value or the torque of the motor detected by the torque detection means, and ηm is the efficiency of the motor. is there. In this case, the rotation speed detection sensor and the torque detection means constitute the load measurement means of the present invention.
Furthermore, when the load driven by the electric motor is a hydraulic pump such as the pilot pump 32, the sub pump 34, etc., the electric power supplied to the electric motor driving the hydraulic pump using the following formula (9) or formula (10): Pmi can be determined.
Pmi = (ωp × v × pr) / ηp / ηm (9)
Pmi = (Lp × pr) / ηp / ηm (10)
In the above formulas (9) and (10), ωp is the number of revolutions of the hydraulic pump, v is the volume of the hydraulic pump, pr is the discharge pressure of the hydraulic pump, ηp is the pump efficiency of the hydraulic pump, and ηm is the electric motor that drives the hydraulic pump The motor efficiency Lp is the flow rate of the hydraulic pump. In the case where the above equations (9) and (10) are used, the rotational speed of the hydraulic pump is the rotational speed to the electric motor when the rotational speed command is output from the control device 18 to the electric motor that drives the hydraulic pump. It can be obtained from the command value, and when the rotational speed command is not output, it can be detected by providing a rotational speed detection sensor. Further, the volume of the hydraulic pump is a fixed value if it is a constant displacement pump, and if it is a variable displacement pump, if the displacement command is output from the control device 18 to the displacement variable means of the hydraulic pump, the displacement It can be obtained from the capacity command value to the variable means, and when the capacity command is not output, it can be detected by providing a capacity detection sensor. The discharge pressure of the hydraulic pump can be detected by providing a pressure sensor. Furthermore, the flow rate of the hydraulic pump can be detected by providing a flow rate detection sensor. In this case, the rotation speed detection sensor, the capacity detection sensor, the pressure sensor, and the flow rate detection sensor constitute the load measuring means of the present invention.

  Furthermore, in the second embodiment, an average value within the set time can also be used as the power consumption Pf of the load used when setting the engine target speed ωc. Alternatively, an instantaneous value is used as the power consumption Pf of the load, but the engine target rotation speed command value ωc and the generator motor target command value Pgc can be averaged within the set time and output. When the average value is used or the averaging process is performed in this manner, it is possible to avoid excessive fluctuations in the engine target speed ωc and the engine target output Pes due to a transient change in the load or the like.

  Furthermore, in the present invention, a generator motor having a function of a generator in addition to a function as a motor can be used as a motor supplied with power from a generator motor and a power storage device. For example, an electric motor that drives the turning mechanism can be configured using a generator motor. In this case, the generator motor operates as a generator when the turning mechanism is braked. When such a generator motor is used, the power consumption of the generator motor is calculated by making the plus and minus signs different between when operating as a motor and when operating as a generator. Yes.

  Furthermore, the present invention is configured to set an engine target speed and set an engine target output that maximizes engine efficiency according to the set engine target speed. Since the output corresponds one-to-one as shown in FIG. 5, first, the engine target output is set, and the engine target speed at which the engine efficiency is maximized according to the set engine target output is determined. Even if the configuration is set, an equivalent control system can be provided. In this case, engine output switching means is provided instead of the engine speed setting means, and the engine target output is set according to the operation value of the engine output switching means, or the engine target output is set according to the power consumption of the load. The target engine speed is set according to the set engine target output.

  Further, in performing the engine drive / stop switching control according to the charge amount of the charging device, in the first and second embodiments, the charge amount of the power storage device falls within a preset high efficiency range. However, the present invention is not limited to this. For example, the engine drive / stop is switched so that the charge amount of the power storage device falls within a preset full charge range (for example, In addition, the range of 90% or more of the charge amount is set as the full charge range, the drive reference value is set to 90% charge, and the stop reference value is set to 100% charge), or the charge amount of the power storage device is the upper limit. The engine continues to be driven until reaching the value, and after reaching the upper limit value, the engine is stopped until the preset empty charge range is reached (for example, a range of 10% or less of the charge amount is set to the empty charge range). And sets as the charge of 10% of drive reference values, it is also possible to set the charge amount of 100%) a stop reference value. Further, there is provided a reference value setting means by which a serviceman or an operator can arbitrarily set a reference value (drive reference value and stop reference value) of the charge amount of the power storage device for switching between driving and stopping of the engine. You can also

  Further, when the generator motor is operating as a generator, the power storage device stores the surplus power when there is surplus in the output of the generator motor relative to the output of the motor, and the insufficient power when the power is insufficient. In the first and second embodiments, the storage and discharge of the power storage device are automatically performed according to the difference between the voltage of the bus and the voltage of the power storage device. However, the present invention is not limited to this, and the power storage device can be stored and discharged based on a control command from the control device. In this case, storage / discharge control means for controlling storage / discharge of the power storage device based on a control command from the control device is required, and the control device calculates a difference between the output of the generator motor and the output of the motor. Based on the difference, a control command is output to the storage / discharge control means.

  Further, the present invention is not limited to the hybrid hydraulic excavator and can be implemented in various hybrid construction machines, and the number of hydraulic pumps connected to the engine via the power transmission mechanism is not limited to one. But it ’s okay. Of course, the load driven by the electric motor is appropriately provided according to the type and size of the hybrid type construction machine or the contents of work performed by the hybrid type construction machine.

  INDUSTRIAL APPLICABILITY The present invention can be used to improve engine efficiency in a parallel hybrid construction machine in which an engine, a hydraulic pump, and a generator motor are mechanically connected in parallel.

DESCRIPTION OF SYMBOLS 1 Hybrid type hydraulic excavator 12 Engine 13 Power storage device 14 Hydraulic pump 15 Generator motor 16 Power transmission mechanism 16a Clutch mechanism 17 Engine controller 18 Controller 20 Generator motor controller 22-25 Motor controller 26 Motor for turning 27 Motor for pilot pump 28 Electric motor for cooling fan 29 Electric motor for sub pump 36 Charge amount sensor 37 Voltage sensor 38 Pump rotation speed detection sensor 39 Pump capacity detection sensor 40 Pump discharge pressure detection sensor 42 Rotation speed switching dial 43, 57 Engine / generator motor controller 44 Drive / stop Reference value setting unit 45 Drive / stop determination unit 46, 60 Engine target rotation speed setting unit 47, 61 Engine target output setting unit 48 Pump output calculation unit 50 Drive / stop switching unit 52 Generator motor output command value calculation unit 5 6 Power Storage Device Current Sensor 59 Load Calculation Unit A Hydraulic Actuator

Claims (7)

  Engine, hydraulic pump, load driven by supply of pressure oil from the hydraulic pump, a generator motor functioning as a generator and a motor, and power for mechanically connecting the engine, the hydraulic pump, and the generator motor in parallel A transmission mechanism, an electric motor, a load driven by the electric motor, and a power storage device having a storage / discharge function are provided, and the generator motor, the motor, and the power storage device are connected so that power can be exchanged between them. In this hybrid construction machine, engine control means for controlling the rotational speed of the engine, generator motor control means for controlling the output of the generator motor, and motor control for controlling the output or rotational speed or torque of the motor Means, power transmission intermittent means for interrupting power transmission by the power transmission mechanism, these engine control means, generator motor control And a control device for outputting a control command to the motor control means and the power transmission intermittent means, and a pump output measuring means for measuring the output of the hydraulic pump, and the control device sets an engine target rotational speed. Engine target rotation speed setting means, and engine target output setting means for setting an engine target output that maximizes the engine efficiency according to the set engine target rotation speed. A generator / motor target output for setting the engine output to the engine target output based on the output of the hydraulic pump measured by the pump output measuring means while outputting a control command to the engine control means to obtain the engine target revolution speed And a control command is sent to the generator motor control means to set the generator motor output to the generator motor target output. Control system in a hybrid-type construction machine, characterized in that the force.   In claim 1, the control device obtains a deviation between the engine target rotational speed and the engine actual rotational speed in calculating the generator motor target output for setting the engine output to the engine target output based on the output of the hydraulic pump. A control system for a hybrid construction machine, wherein the generator motor target output is increased or decreased so as to eliminate the deviation.   3. The engine target speed setting unit according to claim 1 or 2, wherein an engine speed control unit is provided for an operator to arbitrarily switch the engine speed, and the engine target speed setting unit is set according to an operation value of the engine speed switching unit. A control system for a hybrid type construction machine, characterized in that   3. The load measuring means according to claim 1 or 2, wherein load measuring means for measuring power consumed by a load driven by pressure oil supplied from a hydraulic pump and a load driven by an electric motor is provided. A control system for a hybrid construction machine, wherein the target engine speed is set in accordance with the power consumption of the load measured by the method.   The engine target speed setting means corrects the engine target speed in accordance with the rate of change in power consumption of the load, and the engine target output setting means is based on the corrected engine target speed. A control system for a hybrid construction machine, characterized by setting an engine target output.   The charge amount detection means for detecting the charge amount of the power storage device is provided according to any one of claims 1 to 5, and the control device performs switching control of driving and stopping of the engine according to the charge amount of the power storage device. Control in a hybrid construction machine comprising drive / stop switching means, and outputting a control command to the power transmission intermittent means for interrupting power transmission between the engine, the hydraulic pump and the generator motor when the engine is stopped system.   7. The drive / stop switching unit according to claim 6, wherein the drive / stop switching unit drives the engine so that a charge amount of the power storage device falls within a high efficiency range preset as a range in which a charge / discharge capacity per unit time of the power storage device is large. A control system for a hybrid type construction machine, characterized in that it performs stop switching control.

Images