JP2011174468A - Engine, hydraulic pump, and control device for generator motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To operate an operating machine etc. with good responsiveness according to intention of an operator while improving engine efficiency, pump efficiency or the like. <P>SOLUTION: In a required power generation amount calculation part 120, in accordance with the storage state of a capacitor, required power generation amount of a generator motor is calculated. An assist determination part 90 determines whether or not engine torque assist action of the generator motor is performed. When performance of the engine assist action is determined, a generator motor command value switching part 187 is switched to a modulation processing part 97 side, so as to perform the engine torque assist action of the generator motor. When it is determined that the engine torque assist action is not performed, rotational frequency control of the generator motor is turned off, so as to prevent the engine torque assist action, and power generation action of the generator motor is performed so as to obtain power generation amount corresponding to the required power generation amount calculated by the required power generation amount calculation part 120. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device for an engine, a hydraulic pump, and a generator motor, and more particularly to a control device used when a hydraulic pump is driven by an engine.

  Construction machines such as hydraulic excavators, bulldozers, dump trucks, and wheel loaders are equipped with diesel engines.

  The configuration of a conventional construction machine 1 will be schematically described with reference to FIG. 1. As shown in FIG. 1, a hydraulic pump 3 is driven using a diesel engine 2 as a drive source. As the hydraulic pump 3, a variable displacement hydraulic pump is used, and the capacity q (cc / rev) is changed by changing the tilt angle of the swash plate 3a. Pressure oil discharged from the hydraulic pump 6 at a discharge pressure PRP and a flow rate Q (cc / min) is supplied to the hydraulic actuators 31 to 36 such as the boom hydraulic cylinder 31 via the operation valves 21 to 26. The operation valves 21 to 26 are actuated by operation of the operation levers 41, 42, 43, 44. By supplying the hydraulic oil to each hydraulic actuator 31-36, each hydraulic actuator 31-36 is driven, and a working machine including a boom, an arm, and a bucket connected to each hydraulic actuator 31-36, an upper swing body, Undercarriage operates.

  While the construction machine 1 is in operation, the load applied to the work implement, the upper swing body, and the lower traveling body constantly changes according to the excavated soil quality, the traveling path gradient, and the like. In accordance with this, the load (oil machine load) of the hydraulic equipment (hydraulic pump 3), that is, the load applied to the engine 2 changes.

  Control of the output P (horsepower; kw) of the diesel engine 2 is performed by adjusting the amount of fuel injected into the cylinder. This adjustment is performed by controlling the governor 4 attached to the fuel injection pump of the engine 1. As the governor 4, an all-speed control type governor is generally used, and the engine speed n and the fuel injection amount (torque T) according to the load so that the target engine speed set by the fuel dial is maintained. ) And are adjusted. That is, the governor 4 increases or decreases the fuel injection amount so that the difference between the target rotational speed and the engine rotational speed is eliminated.

FIG. 2 shows a torque diagram of the engine 2. The horizontal axis represents the engine speed n (rpm; rev / min), and the vertical axis represents the torque T (N · m).

The area defined by the maximum torque line R in FIG. 2 indicates the performance that the engine 2 can produce. The governor 4 controls the engine 2 so that the torque T does not exceed the maximum torque line R and the exhaust smoke limit is not reached, and the engine speed n does not exceed the high idle speed nH to cause overspeed. At the rated point V on the maximum torque line R, the output (horsepower) P of the engine 2 becomes maximum. J indicates an equal horsepower curve in which the horsepower absorbed by the hydraulic pump 3 is equal horsepower.

  When the maximum target rotational speed is set by the fuel dial, the governor 4 adjusts the speed on the maximum speed regulation line Fe connecting the rated point V and the high idle point nH.

  As the load on the hydraulic pump 3 increases, the matching point at which the output of the engine 2 and the pump absorption horsepower balance moves to the rated point V side on the highest speed regulation line Fe. When the matching point moves to the rated point V side, the engine speed n is gradually reduced, and at the rated point V, the engine speed n becomes the rated speed.

  If the engine speed n is fixed at a substantially constant high speed in this way, there is a problem that the fuel consumption rate is large (poor) and the pump efficiency is low.

  The fuel consumption rate (hereinafter referred to as fuel consumption) refers to the amount of fuel consumed per hour and output of 1 kW, and is an index of the efficiency of the engine 2. The pump efficiency is the efficiency of the hydraulic pump 3 defined by volumetric efficiency and torque efficiency.

  In FIG. 2, M indicates an equal fuel consumption curve. The fuel consumption is minimized at M1 that is the valley of the equal fuel consumption curve M, and the fuel consumption increases toward the outside from the fuel consumption minimum point M1.

  As is clear from FIG. 2, the regulation line Fe corresponds to a region where the fuel consumption is relatively high on the equal fuel consumption curve M. For this reason, according to the conventional control method, fuel consumption is large (poor), which is not desirable for engine efficiency.

  On the other hand, in the case of the variable displacement hydraulic pump 3, in general, when the discharge pressure PRP is the same, the larger the pump capacity q (swash plate tilt angle), the higher the volume efficiency and torque efficiency, and the higher the pump efficiency. Are known.

  As is clear from the following equation (1), if the flow rate Q of the pressure oil discharged from the hydraulic pump 3 is the same, the pump capacity q is increased as the rotational speed n of the engine 2 is decreased. Can do. For this reason, if the engine 2 is slowed down, the pump efficiency can be increased.

Q = n · q (1)
Therefore, in order to increase the pump efficiency of the hydraulic pump 3, the engine 2 may be operated in a low speed region where the rotational speed n is low.

  However, as is clear from FIG. 2, the regulation line Fe corresponds to a high speed region of the engine 2. For this reason, according to the conventional control method, there exists a problem that pump efficiency is low.

  In addition, when the engine 2 is operated on the regulation line, the engine speed decreases when the load is high, which may lead to engine stall.

A control method in which the engine speed is changed according to the lever operation amount and the load is described in Patent Document 1 below, in contrast to the control method in which the engine speed is substantially fixed regardless of the load.

  That is, in Patent Document 1, as shown in FIG. 2, a target engine operating line L0 passing through the fuel efficiency minimum point is set.

  Then, based on the operation amount of each operation lever 41, 42, 43, 44, etc., the required rotational speed of the hydraulic pump 3 is calculated, and the first engine required rotational speed corresponding to this pump required rotational speed is calculated. . Further, the required engine horsepower is calculated based on the operation amount of each operation lever 41, 42, 43, 44, etc., and the second required engine speed corresponding to this engine required horsepower is calculated. Here, the second required engine speed is calculated as the engine speed on the target engine operating line L0 in FIG. Then, the engine speed and the engine torque are controlled so that the larger engine target speed of the first and second engine required speeds can be obtained.

  As shown in FIG. 2, when the rotational speed of the engine 2 is controlled along the target engine operating line L0, fuel efficiency, engine efficiency, and pump efficiency are improved. This is because, even when the same horsepower is output and the same required flow rate is obtained, the point pt2 on the target engine operating line L0 is the same point on the equal horsepower line J rather than matching at the point pt1 on the regulation line Fe. This is because the matching is performed at a point close to the minimum fuel consumption point M1 on the equal fuel consumption curve M because the pump displacement q is increased from high rotation and low torque to low rotation and high torque. . Further, when the engine 2 is operated in the low rotation region, noise is improved, and engine friction, pump unload loss, and the like are improved.

  In the field of construction machinery, a hybrid construction machine that assists the driving force of an engine with a generator motor is being developed, and many patent applications have already been filed.

In Patent Document 2, when FIG. 2 is used, the engine 2 is controlled along the regulation line Fe0 corresponding to the set rotational speed set by the fuel dial. When the target rotational speed nr corresponding to the point A where the regulation line Fe0 and the target engine operating line L0 intersect is obtained, and the deviation between the engine target rotational speed nr and the current engine rotational speed n is positive, the generator motor , And the driving force of the engine 2 is assisted by the torque generated by the generator motor. When the deviation is negative, the generator motor is caused to generate power and the electric power is accumulated in the capacitor.
JP-A-11-2144 JP 2003-28071 A

  In the invention described in Patent Document 1, the target engine speed is determined according to the load of the hydraulic pump 3. In FIG. 2, the higher the load on the hydraulic pump 3, the more the matching point moves from B to A on the high load side on the target engine operating line L0.

  However, even if the engine speed is increased from the state where the engine 2 is matched at the low rotation point B to the target high rotation point A, the absorption of the hydraulic pump 3 is absorbed at the low rotation matching point B. Since the torque is small, the work implements (lower traveling body, upper swinging body) may operate only very slowly even if each of the operation levers 41 to 44 is moved greatly at the beginning of the rise of engine rotation. For this reason, the work implement or the like does not operate with good responsiveness to the operation levers 41 to 44, giving the operator a sense of incongruity in operation and reducing work efficiency.

  On the other hand, in the invention described in Patent Document 2, the matching point moves from C to A along the regulation line Fe0. The higher the load on the hydraulic pump 3, the more the matching point moves to the high load side on the regulation line Fe0.

  When moving from the low load side matching point C on the regulation line Fe0 to the high load side matching point A, the engine speed n is gradually reduced. As the engine speed n decreases, the output accumulated on the flywheel of the engine 2 momentarily goes outside, and the apparent output becomes larger than the actual output of the engine 2. For this reason, it is said that the movement of the matching point along the regulation line is originally responsive.

  However, in Patent Document 2, the target engine speed nr is uniquely determined by the setting of the fuel dial, and the engine speed n varies only slightly along the regulation line Fe0. Like the movement from the point B to the point A on the target engine operation line L0, the engine speed does not vary greatly along the target engine operation line L0 according to the load of the hydraulic pump 3. For this reason, unless the fuel dial is set, there is a problem that the engine 2 does not operate in a low rotation region, and pump efficiency, fuel consumption, and noise are deteriorated.

  SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is an object of the present invention to operate a work machine or the like with high responsiveness as intended by an operator while improving engine efficiency, pump efficiency, and the like. It is.

The first invention is
A hydraulic pump driven by an engine;
A hydraulic actuator to which pressure oil discharged from the hydraulic pump is supplied;
A generator motor connected to the output shaft of the engine;
A battery that accumulates the power generated by the generator motor and supplies power to the generator motor;
A calculation means for calculating the required power generation amount of the generator motor according to the storage state of the battery,
Engine target speed setting means for setting a target engine speed;
Maximum torque line setting means for setting a maximum torque line indicating the maximum absorption torque that can be absorbed by the hydraulic pump according to the engine target speed,
A speed control means for controlling the engine speed so that the engine speed matches the current engine target speed;
Capacity control means for controlling the capacity of the hydraulic pump so as to obtain a pump absorption torque whose upper limit is the pump absorption torque on the maximum torque line corresponding to the current target engine speed;
A determination means for determining whether or not to cause the generator motor to act as an engine torque assist, or not to act as an engine torque; and
When it is determined by the determination means that the generator motor is to perform the engine torque assist operation, the generator motor is operated to perform the engine torque assist, and when it is determined that the generator motor is not to perform the engine torque assist operation, It is a control device for an engine, a hydraulic pump, and a generator motor provided with a generator motor control means for generating electricity according to the quantity.

The second invention is
A hydraulic pump driven by an engine;
A hydraulic actuator to which pressure oil discharged from the hydraulic pump is supplied;
A generator motor connected to the output shaft of the engine;
A battery that accumulates the power generated by the generator motor and supplies power to the generator motor;
A calculation means for calculating the required power generation amount of the generator motor according to the storage state of the battery,
Engine target speed setting means for setting a target engine speed;
First maximum torque line setting means for setting a first maximum torque line indicating a maximum absorption torque that can be absorbed by the hydraulic pump in accordance with the target engine speed;
Second maximum torque line setting means for setting a second maximum torque line for increasing the maximum absorption torque in the engine low rotation region with respect to the first maximum torque line;
A speed control means for controlling the engine speed so that the engine speed matches the current engine target speed;
A determination means for determining whether or not to cause the generator motor to act as an engine torque assist, or not to act as an engine torque; and
When it is determined by the determination means that the generator motor is to be subjected to engine torque assist, the second maximum torque line is selected as the maximum torque line, and the second maximum torque line corresponding to the current engine target rotational speed is selected. When the capacity of the hydraulic pump is controlled so as to obtain a pump absorption torque whose upper limit is the pump absorption torque, and the determination means determines that the generator motor does not act as an engine torque assist, the first torque line is set as the maximum torque line. Capacity control means for controlling the capacity of the hydraulic pump so as to obtain a pump absorption torque whose upper limit is the pump absorption torque on the first maximum torque line corresponding to the current engine target speed When,
When it is determined by the determination means that the generator motor is to perform the engine torque assist operation, the generator motor is operated to perform the engine torque assist, and when it is determined that the generator motor is not to perform the engine torque assist operation, It is a control device for an engine, a hydraulic pump, and a generator motor provided with a generator motor control means for generating electricity according to the quantity.

The third invention is the first invention or the second invention,
The judging means is
When the absolute value of the deviation between the engine target speed and the actual engine speed is greater than or equal to a predetermined threshold value, it is determined that the generator motor is to be acted on by the engine torque, and the engine target speed and the engine When the absolute value of the deviation from the actual rotational speed is smaller than a predetermined threshold, it is determined that the generator motor is not allowed to act as an engine torque assist.

The fourth invention is the third invention,
A storage amount calculating means for calculating a storage amount that the capacitor is currently storing;
The determination means includes
When the calculated amount of stored electricity is equal to or less than a predetermined threshold value, it is determined that the generator motor is not allowed to act as an engine torque assist.

The fifth invention is the third invention,
A turning electric motor for turning the upper turning body of the construction machine;
A turning operation means for turning the upper turning body;
Control means for driving and controlling the swing motor in accordance with the turning operation by the turning operation means;
Output calculation means for calculating the current output of the swing motor;
Computation means for computing the required power generation amount of the generator motor according to the storage state of the capacitor and the drive state of the swing motor,
The determination means includes
When the current output of the swing motor is equal to or greater than a predetermined threshold value, it is determined that the generator motor is not allowed to act as an engine torque assist.

A sixth invention is the first invention to the fifth invention,
When the current engine speed is smaller than the engine target speed, the generator motor control means adds the shaft torque of the engine on the engine torque diagram so that the engine speed is equal to the engine target speed. The output torque of the generator motor is controlled so that the engine speed is the same. If the current engine speed is greater than the target engine speed, the engine speed is absorbed by absorbing the engine shaft torque on the engine torque diagram. The output torque of the generator motor is controlled so that the number is equal to the engine target speed.

A seventh invention is the first invention to the sixth invention,
Torque control means for controlling the torque of the generator motor within a range of a torque upper limit value or less during engine torque assist operation of the generator motor;
Torque upper limit value setting means for gradually reducing the torque upper limit value as the amount of electricity stored in the capacitor decreases from the first predetermined value to a second predetermined value smaller than the first predetermined value. It is characterized by.
An eighth invention is the first invention to the sixth invention,
Torque control means for controlling the torque of the generator motor within a range of a torque upper limit value or less during engine torque assist operation of the generator motor;
The torque upper limit value is gradually reduced as the amount of electricity stored in the battery decreases from the first predetermined value to a second predetermined value smaller than the first predetermined value, while the torque upper limit value once reduced. Is increased, the torque upper limit value gradually increases as the storage amount of the battery increases from the third predetermined value to the fourth predetermined value that is larger than the third predetermined value. And a value setting means.
A ninth invention is the fifth invention or the sixth invention,
Torque control means for controlling the torque of the generator motor within a range of a torque upper limit value or less during engine torque assist operation of the generator motor;
Torque upper limit setting means for gradually decreasing the torque upper limit as the current output of the swing motor increases from a first predetermined value to a second predetermined value greater than the first predetermined value. It is characterized by that.
The tenth invention is the fifth invention or the sixth invention,
Torque control means for controlling the torque of the generator motor within a range of a torque upper limit value or less during engine torque assist operation of the generator motor;
As the current output of the swing motor increases from the first predetermined value to the second predetermined value that is larger than the first predetermined value, the torque upper limit value is gradually decreased while the torque once reduced When increasing the upper limit value, the torque upper limit value is gradually increased as the current output of the swing motor decreases from the third predetermined value to the fourth predetermined value smaller than the third predetermined value. Torque upper limit value setting means.
The eleventh invention is the first invention,
The generator motor control means is
Immediately after switching the generator motor from the engine torque assist operation to the power generation operation, control is performed so that the power generation torque of the generator motor is gradually changed from the torque at the end of the assist to the power generation torque corresponding to the required power generation amount of the generator motor. It is a thing.

The twelfth invention
A hydraulic pump driven by an engine;
A hydraulic actuator to which pressure oil discharged from the hydraulic pump is supplied;
A generator motor connected to the output shaft of the engine;
A battery that accumulates the power generated by the generator motor and supplies power to the generator motor;
A calculation means for calculating the required power generation amount of the generator motor according to the storage state of the battery,
Engine target speed setting means for setting a target engine speed;
First maximum torque line setting means for setting a first maximum torque line indicating a maximum absorption torque that can be absorbed by the hydraulic pump in accordance with the target engine speed;
Second maximum torque line setting means for setting a second maximum torque line for increasing the maximum absorption torque in the engine low rotation region with respect to the first maximum torque line;
A speed control means for controlling the engine speed so that the engine speed matches the current engine target speed;
A determination means for determining whether or not to cause the generator motor to act as an engine torque assist, or not to act as an engine torque; and
When it is determined by the determination means that the generator motor is to perform the engine torque assist operation, the generator motor is operated to perform the engine torque assist, and when it is determined that the generator motor is not to perform the engine torque assist operation, The hydraulic pump as the generator motor control means for generating electric power according to the amount and the torque upper limit value at the time of assisting the generator motor decrease from the first predetermined value to the second predetermined value smaller than the first predetermined value. A third pump maximum absorption torque calculating means for calculating a third maximum torque by which the maximum absorption torque of the first pump is gradually reduced;
If it is determined by the determination means that the generator motor is to be subjected to engine torque assist, the pump absorption torque on the second maximum torque line corresponding to the current engine target speed or the third pump maximum absorption torque calculation means When the hydraulic pump capacity is controlled by setting the smaller one of the calculated third pump maximum absorption torques as the upper limit of the pump absorption torque, and when it is determined by the determination means that the generator motor does not act on the engine torque, A pump capacity control means for controlling the capacity of the hydraulic pump so as to obtain a pump absorption torque whose upper limit is the pump absorption torque on the first maximum torque line corresponding to the current engine target speed;
And a control device for a hydraulic pump and a generator motor.

The thirteenth invention
A hydraulic pump driven by an engine;
A hydraulic actuator to which pressure oil discharged from the hydraulic pump is supplied;
A generator motor connected to the output shaft of the engine;
A battery that accumulates the power generated by the generator motor and supplies power to the generator motor;
A calculation means for calculating the required power generation amount of the generator motor according to the storage state of the battery,
Engine target speed setting means for setting a target engine speed;
First maximum torque line setting means for setting a first maximum torque line indicating a maximum absorption torque that can be absorbed by the hydraulic pump in accordance with the target engine speed;
Second maximum torque line setting means for setting a second maximum torque line for increasing the maximum absorption torque in the engine low rotation region with respect to the first maximum torque line;
A speed control means for controlling the engine speed so that the engine speed matches the current engine target speed;
A determination means for determining whether or not to cause the generator motor to act as an engine torque assist, or not to act as an engine torque; and
When it is determined by the determination means that the generator motor is to perform the engine torque assist operation, the generator motor is operated to perform the engine torque assist, and when it is determined that the generator motor is not to perform the engine torque assist operation, The hydraulic pump as the generator motor control means for generating electric power according to the amount and the torque upper limit value at the time of assisting the generator motor decrease from the first predetermined value to the second predetermined value smaller than the first predetermined value. A third pump maximum absorption torque calculating means for calculating a third maximum torque by which the maximum absorption torque of the first pump is gradually reduced;
If it is determined by the determination means that the generator motor is to be subjected to engine torque assist, the pump absorption torque on the second maximum torque line corresponding to the current engine target speed or the third pump maximum absorption torque calculation means When the hydraulic pump capacity is controlled by setting the smaller one of the calculated third pump maximum absorption torques as the upper limit of the pump absorption torque, and when it is determined by the determination means that the generator motor does not act on the engine torque, The capacity of the hydraulic pump is controlled so that the pump absorption torque with the upper limit of the pump absorption torque on the first maximum torque line corresponding to the current engine target speed is obtained, and the maximum absorption torque of the hydraulic pump is selected. When switched, the pump maximum absorption torque before switching is changed from the pump maximum absorption torque before switching. To the maximum absorption torque, and the pump displacement control means for gradually changing,
And a control device for a hydraulic pump and a generator motor.

In a fourteenth aspect based on the thirteenth aspect,
The time constant for changing from the pump maximum absorption torque before switching to the pump maximum absorption torque after switching is greater than the case where the pump maximum absorption torque before switching is smaller than the pump maximum absorption torque after switching. When the pump maximum absorption torque is larger than the pump maximum absorption torque after switching, it is set to a larger value.

According to the first invention, as shown in FIG. 16, the required power generation amount calculation unit 120 calculates the required power generation amount Tgencom of the generator motor 11 according to the storage state of the battery 12.

  Then, in the assist presence / absence determination unit 90, it is determined whether the generator motor 11 is to perform the engine torque assist operation (determination result T) or whether the engine torque assist operation is not performed (determination result F).

When the assist presence / absence determination unit 90 determines that the generator motor 11 is to be subjected to engine torque assist (determination result T), the generator motor command value switching unit 187 is switched to the T side, that is, the modulation processing unit 97 side. Then, the generator motor 11 is caused to act as an engine torque assist. On the other hand, when the assist presence / absence determination unit 90 determines that the engine motor 11 does not perform the engine torque assist operation (determination result F), the generator motor command value switching unit 187 is switched to the F side, and the generator motor is 11 is turned off so that the engine torque assist operation is not performed, and the generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side. Power generation is performed so that a power generation amount corresponding to the required power generation amount Tgencom calculated by the required power generation amount calculation unit 120 is obtained.

As described above, according to the first aspect of the invention, the generator motor 11 performs the power generation according to the required power generation amount without causing the engine torque assist action or the engine torque assist action depending on the necessity of the engine torque assist action. Since it did in this way, while being able to maintain stably the state of charge of the electrical storage device 12 always at the target state, the operativity of a working machine and an upper turning body can always be maintained at a high level.

  According to the second invention, as shown in FIG. 16, the required power generation amount calculation unit 120 calculates the required power generation amount Tgencom of the generator motor 11 according to the storage state of the battery 12.

  In the first pump target absorption torque calculation unit 66, a first maximum torque line 66a indicating the maximum absorption torque that can be absorbed by the hydraulic pump 3 is set according to the engine target rotational speed.

  In the second pump target absorption torque calculation unit 85, a second maximum torque line 85a that increases the maximum absorption torque in the engine low rotation region is set with respect to the first maximum torque line 66a.

  Then, in the assist presence / absence determination unit 90, it is determined whether the generator motor 11 is to perform the engine torque assist operation (determination result T) or whether the engine torque assist operation is not performed (determination result F).

When the assist presence / absence determination unit 90 determines that the generator motor 11 is to be subjected to engine torque assist (determination result T), the pump absorption torque command value switching unit 88 is on the T side, that is, the second pump target absorption torque. The pump is switched to the calculation unit 85 side, the second maximum torque line 85a is selected as the maximum torque line, and the pump absorption torque on the second maximum torque line 85a corresponding to the current engine target rotational speed is the upper limit. The capacity of the hydraulic pump 3 is controlled so that the absorption torque can be obtained. On the other hand, when the assist presence / absence determination unit 90 determines that the generator motor 11 does not perform the engine torque assist operation (determination result F), the pump absorption torque command value switching unit 88 is on the F side, that is, the first pump target Switching to the absorption torque calculation unit 66 side, the first maximum torque line 66a is selected as the maximum torque line, and the pump absorption torque on the first maximum torque line 66a corresponding to the current engine target speed is set as the upper limit. The capacity of the hydraulic pump 3 is controlled so as to obtain the pump absorption torque.

When the assist presence / absence determination unit 90 determines that the generator motor 11 is to be subjected to engine torque assist (determination result T), the generator motor command value switching unit 187 is switched to the T side, that is, the modulation processing unit 97 side. Then, the generator motor 11 is caused to act as an engine torque assist. On the other hand, when the assist presence / absence determination unit 90 determines that the engine motor 11 does not perform the engine torque assist operation (determination result F), the generator motor command value switching unit 187 is switched to the F side, and the generator motor is 11 is turned off so that the engine torque assist operation is not performed, and the generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side, and the required power generation amount calculation unit The generator motor 11 is caused to generate power so that a power generation amount corresponding to the required power generation amount Tgencom calculated at 120 is obtained. As described above, in the second invention, similarly to the first invention, depending on the necessity of the engine torque assist action, the engine torque assist action is performed or the engine torque assist action is not performed, and the power generation according to the required power generation amount is performed. Since it was made to perform with the generator motor 11, while being able to maintain stably the amount of electrical storage of the electrical storage device 12 always to the target state, the operativity of a working machine and an upper turning body can always be maintained at a high level.

Moreover, in the second invention, while the engine torque assist action is performed by the generator motor 11,
With respect to the first maximum torque line 66a, the hydraulic pump 3 has a pump absorption torque whose upper limit is the pump absorption torque on the second maximum torque line 85a in which the maximum absorption torque increases in the engine low rotation region. Since the capacity is controlled, it is possible to increase the absorption torque of the hydraulic pump 3 at the initial stage when the engine speed is increased. For this reason, the working machine starts to move quickly with respect to the movement of the operation lever, so that a reduction in work efficiency can be suppressed, and the uncomfortable feeling of operation given to the operator can be reduced. If control is to be performed according to the second maximum torque line L2 without causing the engine torque assist operation by the generator motor 11, the engine 2 may be overloaded. That is, if the capacity of the hydraulic pump 3 is controlled according to the second maximum torque line 85a without the engine torque assisting action, the hydraulic pump 3 absorbs torque exceeding the output of the engine alone, and the engine Not only can the engine speed not be increased, but the engine speed may decrease due to a high load, leading to an engine stall in the worst case. As described above, in the control example 2, the control according to the second maximum torque line 85a is guaranteed on the premise of the engine torque assist action by the generator motor 11.

In the third invention, as shown in FIG. 17, since a threshold value is provided for the deviation Δgenspd and it is determined whether or not the engine torque assist operation is performed, the control is stabilized. In other words, if the engine torque assist action is performed immediately when there is a deviation without setting a threshold for the deviation, the engine torque assist action is continued at an engine speed near the engine target speed. , Leading to energy loss. This is because the energy source for the engine torque assisting action is originally the energy of the engine 2, so that the engine torque assisting action always increases the energy loss by the efficiency of the generator motor 11. Generally, when the generator motor 11 is driven and generated with a small torque, the efficiency decreases.

According to the fourth invention, as shown in FIG. 17, when the voltage value BATTvolt of the battery 12, that is, when the charged amount is equal to or less than the predetermined threshold value BC 1, it is determined that the generator motor 11 is not allowed to act as an engine torque assist. The assist flag assist flag is set to F. As described above, by preventing the engine torque assist operation when the storage amount of the storage battery 12 is low, overdischarge of the storage battery 12 can be avoided, and a decrease in the life of the storage battery 12 can be avoided. In particular, in the case of an electric swivel system, stored energy is required to turn the upper swing body, and if the amount of stored power is excessively reduced, the turning performance is adversely affected. By preventing the engine torque assist operation when the amount of electricity stored in the battery 12 is low, it is possible to avoid deterioration in turning performance due to a reduction in the amount of electricity stored.

According to the fifth invention, as shown in FIG. 17, when the current output SWGpow of the swing motor 103 is equal to or greater than a predetermined threshold value SC1, it is determined that the generator motor motive 11 is not allowed to act on the engine torque, While the engine torque assist operation is prohibited, the required power generation amount Tgencom of the generator motor 11 is calculated in consideration of not only the storage state of the battery 12 (voltage value BATTvolt) but also the drive state of the swing motor 6 (turn load current SWGcurr). Then, power generation corresponding to the required power generation amount Tgencom is performed by the generator motor 11, and the generated power is supplied to the turning motor 103. For this reason, it is possible to turn the upper turning body without lowering the turning performance.

According to the sixth aspect of the present invention, when the rotational speed deviation Δgenspd is larger than a certain value with a sign plus, the generator motor speed command value (generator motor target rotational speed) Ngencom is sent from the modulation processor 97 to the generator motor controller 100. In response to this, the generator controller 100 controls the rotational speed of the generator motor 11 so that the generator motor target rotational speed Ngencom is obtained, and causes the generator motor 11 to be electrically operated. That is, when the current engine speed is smaller than the engine target speed, the generator motor 11 is electrically operated, and the shaft torque of the engine 2 is added on the torque diagram of the engine 2 to increase the engine speed. The output torque of the generator motor 11 is controlled so that the engine speed is equal to the target engine speed.

When the rotation speed deviation Δgenspd is a sign minus and increases to a certain degree or more, a generator motor speed command value (generator motor target rotation speed) Ngencom is output from the modulation processing unit 97 to the generator motor controller 100, and the generator In response to this, the controller 100 controls the rotational speed of the generator motor 11 so that the generator motor target rotational speed Ngencom is obtained, and causes the generator motor 11 to generate power. That is, when the current engine speed is greater than the engine target speed, the generator motor 11 is caused to generate power, absorb the shaft torque of the engine 2 on the engine torque diagram, and decrease the engine speed. The output torque of the generator motor 11 is controlled so that the rotation speed is equal to the engine target rotation speed.

According to the seventh aspect of the present invention, as shown in FIG. 18, the upper limit of the torque that can be generated by the generator motor 11 before switching from the state in which the engine torque assist operation is performed to the state in which the power generation operation according to the required power generation amount is performed. Since the value (torque limit) GENtrqlimit is gradually made smaller in accordance with the decrease in the storage amount (voltage value BATTvolt) of the battery 12, the power generation operation according to the required power generation amount is achieved from the state where the engine torque assist operation is performed. The change in the power generation torque of the generator motor 11 when the state is switched to a smooth state becomes smooth, and it can be avoided that the engine speed decreases during the switching.

According to the eighth invention, as shown in FIG. 18, as the voltage value BATTvolt of the battery 12 decreases from the first predetermined value BD1 to the second predetermined value BD2 smaller than the first predetermined value BD1, While the torque upper limit value (generator motor torque limit) GENtrqlimit of the motor 11 is obtained and outputted as a value that is gradually reduced, the voltage value BATTvolt of the battery 12 is increased when the torque upper limit value GENtrqlimit once reduced is increased. Increases the torque upper limit value (generator motor torque limit) GENtrqlimit of the generator motor 11 as the value increases from the third predetermined value BD3 to the fourth predetermined value BD4 that is larger than the third predetermined value BD3. As output. Thus, by providing hysteresis in the way of changing the generator motor torque limit GENtrqlimit, the control can be performed stably.

According to the ninth invention, as shown in FIG. 18, the upper limit of the torque that can be generated by the generator motor 11 before switching from the state in which the engine torque assist operation is performed to the state in which the power generation operation according to the required power generation amount is performed. Since the value (torque limit) GENtrqlimit is gradually decreased in accordance with the increase in the current output SWGpow of the swing motor 103, the power generation operation corresponding to the required power generation amount is performed from the state in which the engine torque assist operation is performed. The change in the power generation torque of the generator motor 11 when switching to the existing state becomes smooth. For this reason, it is possible to avoid a decrease in engine speed during switching.
According to the tenth aspect, as shown in FIG. 18, as the current output SWGpow of the swing motor 103 increases from the first predetermined value SD1 to the second predetermined value SD2 that is larger than the first predetermined value SD1. When the torque upper limit value (generator motor torque limit) GENtrqlimit of the generator motor 11 is obtained and outputted as a value that is gradually decreased, the torque upper limit value GENtrqlimit once reduced is increased. As the current output SWGpow decreases from the third predetermined value SD3 to the fourth predetermined value SD4 that is smaller than the third predetermined value SD3, the torque upper limit value (generator motor torque limit) GENtrqlimit of the generator motor 11 gradually increases. It is obtained as an increased value and output. Thus, by providing hysteresis in the way of changing the generator motor torque limit GENtrqlimit, the control can be performed stably.

According to the eleventh invention, as shown in FIG. 19, immediately after switching from the state in which the engine torque assist operation is performed to the state in which the power generation operation according to the required power generation amount is performed, the power generation torque of the generator motor 11 is assisted. Since the control for gradually changing the torque from the torque at the end to the power generation torque corresponding to the required power generation amount of the generator motor 11 is performed, the power generation action corresponding to the required power generation amount is performed from the state where the engine torque assist operation is performed. The change in the power generation torque of the generator motor 11 when switching to the current state becomes smooth. For this reason, it is possible to avoid a decrease in engine speed during switching.

According to the twelfth aspect of the invention, as shown in FIG. 16, the third pump maximum absorption torque calculator 106 has a maximum absorption torque (third value) of the hydraulic pump 3 as the torque upper limit value Tgencom2 of the generator motor 11 decreases. The third maximum torque line L3 in which the maximum pump absorption torque (Tpcommax) is gradually reduced is set. According to the twelfth aspect of the invention, the capacity of the hydraulic pump 3 is controlled so that the maximum absorption torque of the hydraulic pump 3 is gradually reduced as the torque upper limit value of the generator motor 11 is reduced. When the power generation action corresponding to the required power generation amount is switched from the current state to the state where the power generation action is performed, the absorption torque of the hydraulic pump 3 decreases in accordance with the decrease in the assist force of the engine 2 and the change in the shaft torque of the engine 2 changes. Smoothness can be avoided, and deterioration of the engine speed acceleration associated with a decrease in the assist force of the engine 2 can be avoided.

According to the thirteenth aspect, as shown in FIG. 16, from the pump maximum absorption torque (third pump maximum absorption torque Tpcommax) on the maximum torque line (for example, the third target torque line L3) before switching, after switching. The maximum torque line (for example, the third target torque) before switching without being directly switched to the pump maximum absorption torque (first pump maximum absorption torque Tpcom1) on the maximum torque line (first maximum torque line L1) From the pump maximum absorption torque on the line L3) (third pump maximum absorption torque Tpcommax), the pump maximum absorption torque on the maximum torque line after switching (first maximum torque line L1) (first pump maximum absorption torque) It gradually changes smoothly over time t to Tpcom1). As a result, the load applied to the output shaft of the engine 2 is suddenly changed due to a sudden change in the pump absorption torque at the time of switching between the state in which the engine torque assist operation is performed and the state in which the power generation operation is performed according to the required power generation amount. It can be avoided that the engine speed decreases.

  In a fourteenth aspect based on the thirteenth aspect, the time constant τ when changing the pump maximum absorption torque before switching from the pump maximum absorption torque after switching to the pump maximum absorption torque after switching by the pump maximum absorption torque before switching. The case where the pump maximum absorption torque before switching is larger than the pump maximum absorption torque after switching is set to a larger value than when the torque is smaller than the torque. This is because when the time constant τ is uniformly set to a large value, when the pump maximum absorption torque is switched from a small state to a large state, the time constant of the change in the pump maximum absorption torque is large. Because it becomes dull.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the present embodiment, a description will be given assuming that a diesel engine and a hydraulic pump mounted on a construction machine such as a hydraulic excavator are controlled.

  FIG. 3 shows the overall configuration of the construction machine 1 according to the embodiment. The construction machine 1 is assumed to be a hydraulic excavator.

  The construction machine 1 includes an upper swing body and a lower traveling body, and the lower traveling body includes left and right crawler tracks. A work machine including a boom, an arm, and a bucket is attached to the vehicle body. The boom is operated by driving the boom hydraulic cylinder 31, the arm is operated by driving the arm hydraulic cylinder 32, and the bucket is operated by driving the bucket hydraulic cylinder 33. Further, the left crawler belt and the right crawler belt are rotated by driving the left traveling hydraulic motor 36 and the right traveling hydraulic motor 35, respectively.

  When the swing hydraulic motor 34 is driven, the swing machinery is driven, and the upper swing body is rotated via a swing pinion, a swing circle, and the like.

  The engine 2 is a diesel engine, and its output (horsepower; kw) is controlled by adjusting the amount of fuel injected into the cylinder. This adjustment is performed by controlling the governor 4 attached to the fuel injection pump of the engine 2.

  As will be described later, the controller 6 outputs a rotation command value for setting the engine speed to the target speed ncom to the governor 4, so that the governor 4 can obtain the target speed ncom by the target torque line L1. Increase or decrease the fuel injection amount.

  The output shaft of the engine 2 is connected to the drive shaft of the generator motor 11 via the PTO shaft 10. The generator motor 11 performs a power generation operation and an electric operation. That is, the generator motor 11 operates as an electric motor (motor) and also operates as a generator. The generator motor 11 also functions as a starter that starts the engine 2. When the starter switch is turned on, the generator motor 11 is electrically operated, and the engine 2 is started by rotating the output shaft of the engine 2 at a low speed (for example, 400 to 500 rpm).

  The generator motor 11 is controlled by an inverter 13. As will be described later, the inverter 13 controls the generator motor 11 in accordance with the generator motor command value GENcom output from the controller 6.

  The inverter 13 is electrically connected to the battery 12 via a DC power line.

  The battery 12 is configured by a capacitor, a storage battery, or the like, and stores (charges) the power generated when the generator motor 11 generates power. In addition, the battery 12 supplies the electric power stored in the battery 12 to the inverter 13. In this specification, a capacitor that accumulates electric power as static electricity and a storage battery such as a lead battery, a nickel metal hydride battery, or a lithium ion battery are also referred to as a “capacitor”.

  The drive shaft of the hydraulic pump 3 is connected to the output shaft of the engine 2 via the PTO shaft 10, and the hydraulic pump 3 is driven by the rotation of the engine output shaft. The hydraulic pump 3 is a variable displacement hydraulic pump, and the capacity q (cc / rev) is changed by changing the tilt angle of the swash plate 3a.

  The pressure oil discharged from the hydraulic pump 3 at the discharge pressure PRp and the flow rate Q (cc / min) is used for the boom operation valve 21, the arm operation valve 22, the bucket operation valve 23, the turning operation valve 24, and the right traveling. They are supplied to the operation valve 25 and the left travel operation valve 26, respectively. The pump discharge pressure PRp is detected by a hydraulic pressure sensor 7 and a hydraulic pressure detection signal is input to the controller 6.

  The hydraulic oil output from the boom operation valve 21, the arm operation valve 22, the bucket operation valve 23, the turning operation valve 24, the right traveling operation valve 25, and the left traveling operation valve 26 is respectively used as a boom hydraulic cylinder. 31, an arm hydraulic cylinder 32, a bucket hydraulic cylinder 33, a turning hydraulic motor 34, a right traveling hydraulic motor 35, and a left traveling hydraulic motor 36. As a result, the boom hydraulic cylinder 31, the arm hydraulic cylinder 32, the bucket hydraulic cylinder 33, the turning hydraulic motor 34, the right traveling hydraulic motor 35, and the left traveling hydraulic motor 36 are driven, and the boom, arm, bucket, The upper track, the left track and the right track of the lower track are activated.

  A work / turning right operation lever 41 and a work / turning left operation lever 42 are provided on the right side and the left side in front of the driver's seat of the construction machine 1, respectively, as well as a traveling right operation lever 43 and a traveling left operation lever. A lever 44 is provided.

  The work / turning right operation lever 41 is an operation lever for operating the boom and the bucket, and operates the boom and the bucket according to the operation direction, and operates the boom and the bucket at a speed according to the operation amount.

  The operation lever 41 is provided with a sensor 45 that detects an operation direction and an operation amount. The sensor 45 inputs a lever signal indicating the operation direction and the operation amount of the operation lever 41 to the controller 6. When the operation lever 41 is operated in the direction in which the boom is operated, the boom lever signal Lb0 indicating the boom raising operation amount and the boom lowering operation amount according to the tilt direction and the tilt amount with respect to the neutral position of the operation lever 41 is transmitted to the controller. 6 is input. Further, when the operation lever 41 is operated in the direction in which the bucket is operated, the bucket lever signal Lbk indicating the bucket excavation operation amount and the bucket dump operation amount according to the tilt direction and the tilt amount with respect to the neutral position of the operation lever 41 is obtained. Input to the controller 6.

  When the operating lever 41 is operated in the direction in which the boom is operated, the pilot pressure (PPC pressure) PRbo corresponding to the tilting amount of the operating lever 41 is adjusted in the lever tilting direction ( Are added to the pilot port 21a corresponding to the boom raising direction and the boom lowering direction).

  Similarly, when the operation lever 41 is operated in the direction in which the bucket is operated, the pilot pressure (PPC pressure) PRbk corresponding to the tilting amount of the operation lever 41 is the lever among the pilot ports of the bucket operation valve 23. It is added to the pilot port 23a corresponding to the tilting direction (bucket excavation direction, bucket dumping direction).

  The work / swirl left operation lever 42 is an operation lever for operating the arm and the upper swing body, and operates the arm and the upper swing body in accordance with the operation direction and at the speed corresponding to the operation amount. Operate the swivel body.

  The operation lever 42 is provided with a sensor 46 that detects an operation direction and an operation amount. The sensor 46 inputs a lever signal indicating the operation direction and the operation amount of the operation lever 42 to the controller 6. When the operation lever 42 is operated in the direction in which the arm is operated, the arm lever signal Lar indicating the arm excavation operation amount and the arm dump operation amount according to the tilt direction and the tilt amount with respect to the neutral position of the operation lever 42 is obtained from the controller. 6 is input. In addition, when the operation lever 42 is operated in a direction to operate the upper swing body, the turn lever indicating the right turn operation amount and the left turn operation amount according to the tilt direction and the tilt amount with respect to the neutral position of the operation lever 42. The signal Lsw is input to the controller 6.

  When the operation lever 42 is operated in the direction in which the arm is operated, the pilot pressure (PPC pressure) PRar corresponding to the amount of tilt of the operation lever 42 is the lever tilt direction ( The pilot port 22a corresponding to the arm excavation direction and the arm dump direction).

  Similarly, when the operation lever 42 is operated in the direction in which the upper swing body is operated, the pilot pressure (PPC pressure) PRsw corresponding to the tilting amount of the operation lever 42 is applied to each pilot port of the turning operation valve 24. Of these, it is added to the pilot port 24a corresponding to the lever tilting direction (right turning direction, left turning direction).

  The traveling right operation lever 43 and the traveling left operation lever 44 are operation levers for operating the right crawler track and the left crawler track, respectively, and actuate the crawler track according to the operation direction and at the speed corresponding to the operation amount. Operate.

  A pilot pressure (PPC pressure) PRcr corresponding to the tilting amount of the operation lever 43 is applied to the pilot port 25a of the right travel operation valve 25.

  The pilot pressure PRcr is detected by the hydraulic pressure sensor 8, and the right traveling pilot pressure PRcr indicating the right traveling amount is input to the controller 6.

  Similarly, a pilot pressure (PPC pressure) PRcl corresponding to the tilting amount of the operation lever 44 is applied to the pilot port 26 a of the left travel operation valve 26.

  The pilot pressure PRcl is detected by the hydraulic pressure sensor 9, and the left traveling pilot pressure PRcl indicating the left traveling amount is input to the controller 6.

  Each of the operation valves 21 to 26 is a flow direction control valve, and moves the spool in a direction corresponding to the operation direction of the corresponding operation lever 41 to 44, and also oils the opening area corresponding to the operation amount of the operation lever 41 to 44. Move the spool so that the path opens.

The pump control valve 5 is operated by a control current pc-epc output from the controller 6, and the pump control valve 5 is changed via a servo piston.
The pump control valve 5 prevents the product of the discharge pressure PRp (kg / cm 2) of the hydraulic pump 3 and the capacity q (cc / rev) of the hydraulic pump 3 from exceeding the pump absorption torque Tp com corresponding to the control current pc-epc. Next, the tilt angle of the swash plate 3a of the hydraulic pump 3 is controlled. This control is called PC control.

  The generator motor 11 is provided with a rotation sensor 14 that detects the current actual rotational speed GENspd (rpm) of the generator motor 11, that is, the actual rotational speed of the engine 2. A signal indicating the actual rotation speed GENspd detected by the rotation sensor 14 is input to the controller 6.

 In addition, the livestock battery 12 is provided with a voltage sensor 15 for detecting the voltage BATTvolt of the livestock battery 12. A signal indicating the voltage BATTvolt detected by the voltage sensor 15 is input to the controller 6.

  The controller 6 outputs a rotation command value to the governor 4 to increase or decrease the fuel injection amount so that the target rotation speed corresponding to the current load of the hydraulic pump 3 is obtained. And adjust the torque T.

  In addition, the controller 6 outputs the generator motor command value GENcom to the inverter 13 to cause the generator motor 11 to generate power or operate. When a command value GENcom for operating the generator motor 11 as a generator is output from the controller 6 to the inverter 13, a part of the output torque generated in the engine 2 is generated via the engine output shaft. Is generated by absorbing the torque of the engine 2. The AC power generated by the generator motor 11 is converted to DC power by the inverter 13 and stored (charged) in the battery 12 via the DC power line.

  Further, when a command value GENcom for operating the generator motor 11 as an electric motor is output from the controller 6 to the inverter 13, the inverter 13 controls the generator motor 11 to operate as an electric motor. That is, electric power is output (discharged) from the battery 12 and the DC power stored in the battery 12 is converted into AC power by the inverter 13 and supplied to the generator motor 11 to rotate the drive shaft of the generator motor 11. As a result, torque is generated in the generator motor 11, and this torque is transmitted to the engine output shaft via the drive shaft of the generator motor 11 and added to the output torque of the engine 2 (the output of the engine 2 is assisted). ). This added output torque is absorbed by the hydraulic pump 3.

  The power generation amount (absorption torque amount) and the motor drive amount (assist amount; generated torque amount) of the generator motor 11 change according to the contents of the generator motor command value GENcom.

  Next, a comparative example of the present embodiment will be described.

  FIG. 1 shows a configuration of a construction machine 1 of a comparative example.

  As can be seen by comparing FIG. 1 and FIG. 3, in the comparative example, the PTO shaft 10, the generator motor 11, the capacitor 12, the inverter 13, the rotation sensor 14, and the voltage sensor 15 in FIG. The electric operation and the power generation operation are not performed.

  The contents of control executed by the controller 6 will be described below.

(Comparative example)
First, a comparative example of this example will be described.
4 and 6 are control block diagrams showing the contents of processing performed by the controller 6.

  As shown in FIG. 4, the hydraulic actuator target flow rate calculation unit 50 is based on the boom lever signal Lbo, the arm lever signal Lar, the bucket lever signal Lbk, the turning lever signal Lsw, the right traveling pilot pressure PRcr, and the left traveling pilot pressure PRcl. The target flow rate Qbo of the corresponding boom hydraulic cylinder 31, the target flow rate Qar of the arm hydraulic cylinder 32, the target flow rate Qbk of the bucket hydraulic cylinder 33, the target flow rate Qsw of the turning hydraulic motor 34, and the target of the right traveling motor 35 The flow rate Qcr and the target flow rate Qcl for each left traveling motor 36 are calculated.

  In the storage device, functional relationships 51a, 52a, 53a, 54a, 55a, and 56a between the operation amount and the target flow rate are stored in a data table format for each hydraulic actuator.

  In the boom target flow rate calculation unit 51, a boom target flow rate Qbo corresponding to the current operation amount in the boom raising direction or the operation amount Lbo in the boom lowering direction is calculated according to the functional relationship 51a.

  The arm target flow rate calculation unit 52 calculates the arm target flow rate Qar corresponding to the current operation amount in the arm excavation direction or the operation amount Lar in the arm dump direction according to the functional relationship 52a.

  In the bucket target flow rate calculation unit 53, the bucket target flow rate Qbk corresponding to the current operation amount in the bucket excavation direction or the operation amount Lbk in the bucket dump direction is calculated according to the functional relationship 53a.

  In the turning target flow rate calculation unit 54, the turning target flow rate Qsw corresponding to the current operation amount in the right turning direction or the operation amount Lsw in the left turning direction is calculated according to the functional relationship 54a.

  The right travel target flow rate calculation unit 55 calculates the right travel target flow rate Qcr corresponding to the current right travel pilot pressure PRcr according to the functional relationship 55a.

  The left travel target flow rate calculation unit 56 calculates the left travel target flow rate Qcl corresponding to the current left travel pilot pressure PRcl according to the functional relationship 56a.

  For calculation processing, the boom up operation amount, arm excavation operation amount, bucket excavation operation amount, and right turn operation amount are treated as plus sign operation amounts, boom lowering operation amount, arm dump operation amount, bucket dump operation amount. The left turn operation amount is treated as a minus sign operation amount.

  In the pump target discharge flow rate calculation unit 60, the sum of the hydraulic actuator target flow rates Qbo, Qar, Qbk, Qsw, Qcr, Qcl calculated by the hydraulic actuator target flow rate calculation unit 50 is set as a pump target discharge flow rate Qsum as follows. Thus, the processing to be obtained is executed.

Qsum = Qbo + Qar + Qbk + Qsw + Qcr + Qcl (2)
Here, the sum of the target flow rates of the hydraulic actuators is used as the pump target discharge flow rate. The maximum target flow rate among the hydraulic actuator target flow rates Qbo, Qar, Qbk, Qsw, Qcr, Qcl is set as the target of the hydraulic pump 3. The discharge flow rate may be used.
In the first engine target speed calculation unit 61, a first engine target speed ncom1 corresponding to the pump target discharge flow rate Qsum is calculated.

  In the storage device, a functional relationship 61a in which the first engine target rotational speed ncom1 increases as the pump target discharge flow rate Qsum increases is stored in a data table format. As shown below, the first engine target speed ncom1 is the minimum engine that can discharge the pump target discharge flow rate Qsum when the hydraulic pump 3 is operated at the maximum capacity qmax, with the conversion constant α. It is given as the number of revolutions.

ncom1 = Qsum / qmax · α (3)
In the first engine speed calculation unit 61, the first engine target speed ncom1 corresponding to the current pump target discharge flow rate Qsum is calculated according to the functional relationship 61a, that is, the above equation (3).

  The determination unit 62 determines whether or not the current pump target discharge flow rate Qsum is larger than a predetermined flow rate (for example, 10 (L / min)). Here, the predetermined flow rate serving as the threshold is set to a flow rate for determining whether or not each of the operation levers 41 to 44 has been operated from the neutral position.

In the second engine target speed setting unit 68, as a result of the determination by the determination unit 62, the current pump target discharge flow rate Qsum is not more than a predetermined flow rate (for example, 10 (L / min)), that is, the determination result is NO. The second engine target speed ncom2 is set to a speed nJ (for example, 1000 rpm) near the low idle speed nL of the engine 2. On the other hand, when the current pump target discharge flow rate Qsum is larger than a predetermined flow rate (for example, 10 (L / min)), that is, when the determination result is YES, the second engine target rotational speed ncom2 is Is set to a rotational speed nM (for example, 1400 rpm) larger than a low idle rotational speed nL of 2.

In the maximum value selection unit 64, the higher engine target speed ncom12 is selected from the first engine target speed ncom1 and the second engine target speed ncom2.
The pump output limit calculation unit 70 shown in FIG. 4 is specifically shown in FIG. In the following, the determination result TRUE is abbreviated as T, and the determination result FALSE is abbreviated as F.

  It is determined that the work pattern of the plurality of hydraulic actuators 21 to 26 is the operation pattern (1) “traveling operation”, and the output limit value Pplimit of the hydraulic pump 3 is adapted to the work pattern “traveling operation”. Is set to Pplimit1.

  The pump output limit calculation unit 70 calculates the output (horsepower) limit value Pplimit of the hydraulic pump 3 according to the work pattern of the plurality of hydraulic actuators 21 to 26.

  As output limit values of the hydraulic pump 3, Pplimit1, plimit2, Pplimit3, Pplimit4, Pplimit5, and Pplimit6 are calculated in advance. The size of the output limit value of the hydraulic pump 3 is set so as to decrease sequentially in the order of Pplimit1, Pplimit2, Pplimit3, Pplimit4, Pplimit5, and Pplimit6 as shown in the torque diagram shown in FIG. And

  That is, when the right traveling pilot pressure Prcr is larger than the predetermined pressure Kc or when the left traveling pilot pressure Prcl is larger than the predetermined pressure Kc (determination T in step 71), the plurality of hydraulic actuators 21 to 26 are operated. It is determined that the work pattern is the work pattern (1) “traveling operation”, and the output limit value Pplimit of the hydraulic pump 3 is set to Pplimit1 so as to match the work pattern “traveling operation”.

  In the same manner, the following determinations are made in steps 72 to 79.

  That is, in step 72, it is determined whether or not the right turn operation amount Lsw is larger than the predetermined operation amount Ksw and the left turn operation amount Lsw is smaller than the predetermined operation amount −Ksw.

  In step 73, it is determined whether or not the boom lowering operation amount Lbo is smaller than a predetermined operation amount -Kbo.

  In step 74, whether or not the boom raising operation amount Lbo is larger than a predetermined operation amount Kbo, whether the arm excavation operation amount La is larger than the predetermined operation amount Ka, or whether the arm dump operation amount La is Whether or not the predetermined operation amount −Ka is smaller than that, or whether or not the bucket excavation operation amount Lbk is larger than the predetermined operation amount Kbk, or the bucket dump operation amount Lbk is smaller than the predetermined operation amount −Kbk. It is determined whether or not.

  In step 75, it is determined whether or not the arm excavation operation amount La is larger than a predetermined operation amount Ka.

  In step 76, it is determined whether or not the bucket excavation operation amount Lbk is larger than a predetermined operation amount Kbk.

  In step 77, it is determined whether or not the discharge pressure PRp of the hydraulic pump 3 is smaller than a predetermined pressure Kp1.

  In step 78, it is determined whether or not the arm dump operation amount La is smaller than a predetermined operation amount -Ka.

  In step 79, it is determined whether or not the bucket dump operation amount Lbk is smaller than a predetermined operation amount -Kbk.

  In step 80, it is determined whether or not the discharge pressure PRp of the hydraulic pump 3 is greater than a predetermined pressure Kp2.

  In step 81, it is determined whether or not the discharge pressure PRp of the hydraulic pump 3 is greater than a predetermined pressure Kp3.

  When the determination at step 71 is F, the determination at step 72 is T, and the determination at step 73 is T, the operation pattern of the hydraulic actuators 21 to 26 is an operation pattern of “turning operation and boom lowering operation” ( 2), the output limit value Pplimit of the hydraulic pump 3 is set to Pplimit6 so as to conform to the work pattern.

  When the judgment of step 71 is F, the judgment of step 72 is T, the judgment of step 73 is F, and the judgment of step 74 is T, the work pattern of the hydraulic actuators 21 to 26 is “turn operation and boom”. It is determined that the work pattern (3) is “work machine operation other than lowering”, and the output limit value Pplimit of the hydraulic pump 3 is set to Pplimit1 so as to match the work pattern.

  When the judgment at step 71 is F, the judgment at step 72 is T, the judgment at step 73 is F, and the judgment at step 74 is F, the work pattern of the plurality of hydraulic actuators 21 to 26 is “single operation of turning operation”. It is determined that the operation pattern is “operation” (4), and the output limit value Pplimit of the hydraulic pump 3 is set to Pplimit6 so as to match the operation pattern.

  When the judgment of step 71 is F, the judgment of step 72 is F, the judgment of step 75 is T, the judgment of step 76 is T, and the judgment of step 77 is T, the work patterns of the plurality of hydraulic actuators 21 to 26 Is determined to be a work pattern (5) of “when the load is small (for example, work for holding earth and sand) by arm excavation operation and bucket excavation operation”, and the output limit of the hydraulic pump 3 is limited so as to conform to the work pattern. The value Pplimit is set to Pplimit2.

  When the judgment of step 71 is F, the judgment of step 72 is F, the judgment of step 75 is T, the judgment of step 76 is T, and the judgment of step 77 is F, the work patterns of the plurality of hydraulic actuators 21 to 26 Is determined to be the work pattern (6) “when the load is large in the arm excavation operation and the bucket excavation operation (for example, excavation work by simultaneous operation of the arm and bucket)”, and the hydraulic pressure is adjusted so as to conform to the work pattern. The output limit value Pplimit of the pump 3 is set to Pplimit1.

  When the judgment of step 71 is F, the judgment of step 72 is F, the judgment of step 75 is T, and the judgment of step 76 is F, the work pattern of the plurality of hydraulic actuators 21 to 26 is “arm excavation operation”. The output limit value Pplimit of the hydraulic pump 3 is set to Pplimit1 so as to match the work pattern (7).

  If the determination in step 71 is F, the determination in step 72 is F, the determination in step 75 is F, the determination in step 78 is T, the determination in step 79 is T, and the determination in step 80 is T, a plurality of hydraulic pressures The work pattern of the actuators 21 to 26 is determined to be a work pattern (8) of “when the load is large in the arm earthing operation and the bucket earthing operation (for example, earth and sand pushing work by simultaneous earth and bucket earthing operation)”. Then, the output limit value Pplimit of the hydraulic pump 3 is set to Pplimit3 so as to conform to the work pattern.

  If the judgment of step 71 is F, the judgment of step 72 is F, the judgment of step 75 is F, the judgment of step 78 is T, the judgment of step 79 is T, and the judgment of step 80 is F, a plurality of hydraulic pressures The work pattern of the actuators 21 to 26 is determined to be a work pattern (9) of “when the load is small in the arm earthing operation and the bucket earthing operation (for example, the work for returning the arm and the bucket simultaneously in the air)” The output limit value Pplimit of the hydraulic pump 3 is set to Pplimit5 so as to conform to the work pattern.

  If the determination in step 71 is F, the determination in step 72 is F, the determination in step 75 is F, the determination in step 78 is T, the determination in step 79 is F and the determination in step 81 is T, a plurality of hydraulic actuators The work patterns 21 to 26 are determined to be work patterns (10) of “when the load is large due to the single arm earth removal operation (for example, earth and sand pushing work by the arm earth removal work)”, and are adapted to the work pattern. In addition, the output limit value Pplimit of the hydraulic pump 3 is set to Pplimit3.

  If the judgment of step 71 is F, the judgment of step 72 is F, the judgment of step 75 is F, the judgment of step 78 is T, the judgment F of step 79 is F and the judgment of step 81 is F, a plurality of hydraulic actuators The work patterns 21 to 26 are determined to be the work pattern (11) “when the load is small (for example, work to return the arm in the air) by the arm single earth removal operation”, and so as to conform to the work pattern. The output limit value Pplimit of the hydraulic pump 3 is set to Pplimit5.

  When the judgment of step 71 is F, the judgment of step 72 is F, the judgment of step 75 is F, and the judgment of step 78 is F, the work pattern of the plurality of hydraulic actuators 21 to 26 is “other work”. The output limit value Pplimit of the hydraulic pump 3 is set to Pplimit1 so as to match the work pattern (12).

  In the third engine target speed calculator 63, the third engine target speed ncom3 corresponding to the output (horsepower) limit value Pplimit of the hydraulic pump 3 calculated by the pump output limit calculator 70 is calculated.

  In the storage device, a functional relationship 63a in which the third engine target speed ncom3 increases in accordance with the increase in the output limit value Pplimit of the hydraulic pump 3 is stored in a data table format.

  In the third engine speed calculation unit 63, the current working pattern of the plurality of hydraulic actuators 21 to 26, that is, the third engine target speed ncom3 corresponding to the output limit value Pplimit of the hydraulic pump 3 follows the functional relationship 63a. Calculated.

  The minimum value selection unit 65 selects the lower engine target speed ncom, which is the lower one of the engine target speed ncom12 selected by the maximum value selection part 64 and the third engine target speed ncom3.

  The controller 6 outputs to the governor 4 a rotation command value for setting the engine speed n to the target speed ncom so that the governor 4 can obtain the engine target speed ncom on the target torque line L1. Increase or decrease the fuel injection amount.

  The pump absorption torque calculation unit 66 calculates the target absorption torque Tpcom of the hydraulic pump 3 corresponding to the engine target rotation speed ncom.

  In the storage device, a functional relationship 66a in which the target absorption torque Tpcom of the hydraulic pump 3 increases as the engine target speed ncom increases is stored in a data table format. This function 66a is a curve corresponding to the target torque line L1 on the torque diagram shown in FIG.

  A target torque line L1 shown in FIG. 10 is a maximum torque line indicating the maximum absorption torque that can be absorbed by the hydraulic pump 3, and the maximum absorption torque corresponding to each engine speed is set to the upper limit (limit) of the pump absorption torque. ), The capacity of the hydraulic pump 3 is controlled. For example, in the hydraulic pump system, load sensing (LS) control is performed. As a result of the load sensing control, the swash plate tilt angle of the hydraulic pump 3 is determined, and the swash plate tilt angle and the load pressure at that time are determined. Pump absorption torque is determined. If the pump absorption torque is equal to or less than the maximum absorption torque corresponding to the current engine speed on the target torque line L1, the pump capacity is adjusted according to the pump absorption torque determined by load sensing control. When the maximum absorption torque is exceeded, the pump capacity is adjusted according to the maximum absorption torque. Similarly, torque lines L2 and L3 described later are treated as maximum torque lines.

  FIG. 10 shows a torque diagram of the engine 2 as in FIG. 2, where the horizontal axis represents the engine speed n (rpm; rev / min) and the vertical axis represents the torque T (N · m). The function 66a corresponds to the target torque line L1 on the torque diagram shown in FIG.

  The pump absorption torque calculation unit 66 calculates the target absorption torque Tpcom of the hydraulic pump 3 corresponding to the current engine target rotational speed ncom according to the function 66a.

  In the control current calculator 67, a control current pc-epc corresponding to the pump target absorption torque Tpcom is calculated.

  In the storage device, a functional relationship 67a in which the control current pc-epc increases as the pump target absorption torque Tpcom increases is stored in a data table format.

  In the pump absorption torque calculation unit 66, the control current pc-epc corresponding to the current pump target absorption torque Tpcom is calculated according to the functional relationship 67a.

  A control current pc-epc is output from the controller 6 to the pump control valve 5 to change the swash plate 3a of the hydraulic pump 3 via the servo piston. The pump control valve 5 prevents the product of the discharge pressure PRp (kg / cm 2) of the hydraulic pump 3 and the capacity q (cc / rev) of the hydraulic pump 3 from exceeding the pump absorption torque Tp com corresponding to the control current pc-epc. In addition, the tilt angle of the swash plate 3a of the hydraulic pump 3 is PC-controlled.

  Next, the effect of the configuration of such a comparative example will be described with reference to FIG.

  As shown in FIG. 10, when the engine 2 and the hydraulic pump 3 are controlled according to the target torque line L1 in which the pump absorption torque Tpcom decreases as the engine speed n decreases, fuel efficiency, engine efficiency, and pump efficiency are improved. Although the effect of reducing noise and preventing engine stall is obtained, there is a problem that the responsiveness of the engine 2 is poor. That is, for example, even if the operation lever 41 is tilted from the neutral position to start excavation work and the engine 2 is raised from a low rotation, the load on the hydraulic pump 3 is suddenly increased in the initial stage (transient state) at which the lever starts to be tilted. Therefore, the engine output has no margin for the power of the pump absorption horsepower, and the power for accelerating the engine 2 is insufficient. For this reason, the engine 2 may not be raised to the target rotational speed or may be raised only very slowly.

  In this regard, in this comparative example, while setting the first engine target rotational speed ncom1 suitable for the current pump target discharge flow rate Qsum, the current pump target discharge flow rate Qsum is set to a predetermined flow rate (for example, 10 (L / min When it is determined that the engine speed is greater than)), a rotation speed nM (for example, 1400 rpm) larger than the engine low idle rotation speed nL is set as the second engine target rotation speed ncom2. If the second engine target speed ncom2 is equal to or higher than the first engine target speed ncom1, the engine speed is controlled so as to obtain the second engine target speed ncom2, and the second engine target speed The hydraulic pump 3 is controlled so that a pump absorption torque corresponding to several ncom2 is obtained.

  For this reason, for example, when the operation lever 41 is tilted from the neutral position in order to start excavation work, the engine speed increases in advance and the engine torque increases before the load of the hydraulic pump 3 suddenly increases. There is a margin in power for accelerating 2. For this reason, the engine 2 can be rapidly raised from the low speed range to the target speed, and the response of the engine 2 is improved.

  Further, in this comparative example, the first engine target rotational speed ncom1 suitable for the current pump target discharge flow rate Qsum is set, while the hydraulic pump 3 is operated according to the work pattern of the plurality of hydraulic actuators 21 to 26. An output limit value Pplimit is set, and a third engine target speed ncom3 corresponding to this is set. If the third engine target speed ncom3 is equal to or lower than the first engine target speed ncom1, the engine speed is controlled so that the third engine target speed ncom3 is obtained. The hydraulic pump 3 is controlled so as to obtain a corresponding pump absorption torque. For this reason, the pump absorption torque can be set to an appropriate value, and unnecessary energy consumption can be suppressed.

  In FIG. 12, the horizontal axis is time t, and as an example, the work pattern (7), work pattern (5), work pattern (3), work pattern (11), work pattern (12), work pattern (2) When the operations are performed in order, the boom lever signal Lbo, the arm lever signal Lar, the bucket lever signal Lbk, and the turning lever signal Lsw, which are the operation amounts of the operation levers 41 and 42, change over time, and the pump absorption torque Tp. The change and the time change of the engine speed n are respectively shown.

  According to this comparative example, it is confirmed that the pump absorption torque can be set to an appropriate value when working with the series of work patterns shown in FIG. 12, and unnecessary energy consumption can be suppressed more than necessary. It was done.

Example 1
Next, Example 1 will be described.
The configuration of the construction machine 1 according to the first embodiment is as described above with reference to FIG. 3. The PTO shaft 10, the generator motor 11, the capacitor 12, the inverter 13, the rotation sensor 14, and the voltage sensor 15 are compared with the comparative example in FIG. 1. In addition, an electric action and a power generation action by the generator motor 11 are performed.

  5, 6, 7, and 8 are control block diagrams showing the processing contents performed by the controller 6.

  FIG. 5 is a diagram corresponding to FIG. 4 of the comparative example, and a description of the same parts as those in FIG. 4 is omitted.

  As shown in FIGS. 5 and 6, in this embodiment, when the engine target speed ncom is selected by the minimum value selection unit 65 as in the comparative example, the process proceeds to the control block diagram shown in FIG. The processing described below is executed.

  In the following, calculation processing is performed after converting the engine speed and the engine target speed to the generator motor speed and the generator motor target speed, respectively. However, in the following explanation, the generator motor speed and power generation It is also possible to perform the same calculation process by replacing the motor target rotational speed with the engine rotational speed and the engine target rotational speed, respectively.

  In the generator motor target rotational speed calculation unit 96, the target rotational speed Ngencom of the generator motor 11 corresponding to the current engine target rotational speed ncom is calculated by the following equation.

Ngencom = ncom × K2 (4)
Here, K2 is a reduction ratio of the PTO shaft 10.

In the assist presence / absence determination unit 90, the target rotation speed Ngencom of the generator motor 11, the current actual rotation speed GENspd of the generator motor 11 detected by the rotation sensor 14, and the current voltage BATTvolt of the livestock generator 12 detected by the voltage sensor 15. Based on the above, it is determined whether or not the generator motor 11 assists the engine 2 (assist presence / absence).

  The assist presence / absence determination unit 90 is specifically shown in FIG.

  First, the deviation calculation unit 91 calculates a deviation Δgenspd between the generator motor target rotation speed Ngencom and the generator motor actual rotation speed GENspd.

  Next, in the first determination unit 92, when the deviation Δgenspd between the generator motor target rotation speed Ngencom and the generator motor actual rotation speed GENspd is equal to or greater than the first threshold value ΔGC1, the generator motor 11 is electrically operated. The assist flag assist flag is set to T, and the deviation Δgenspd between the generator motor target rotation speed Ngencom and the generator motor actual rotation speed GENspd is equal to or smaller than the second threshold value ΔGC2 which is smaller than the first threshold value ΔGC1. In this case, it is determined that the generator motor 11 is not electrically operated (however, if necessary, the power is generated and the electric power is stored in the battery 12), and the assist flag is set to F.

  Further, when the deviation Δgenspd between the generator motor target rotation speed Ngencom and the generator motor actual rotation speed GENspd becomes equal to or less than the third threshold value ΔGC3, it is determined that the generator motor 11 generates power, and the assist flag assist flag is set to T When the deviation Δgenspd between the generator motor target rotational speed Ngencom and the generator motor actual rotational speed GENspd is equal to or larger than the fourth threshold value ΔGC4 which is larger than the third threshold value ΔGC3, the generator motor 11 generates power. It is determined that the power is not generated (however, if necessary, the electric power is stored in the battery 12), and the assist flag is set to F.

  As described above, when the rotational speed deviation Δgenspd becomes larger than a certain value by a plus sign, the current engine rotational speed and the target rotational speed are different from each other in that the generator motor 11 is electrically operated to assist the engine 2. This is to increase the engine speed quickly toward the target engine speed.

  Further, when the rotational speed deviation Δgenspd is a sign minus and increases to a certain degree or more, the generator motor 11 generates power and the engine 2 is reversely assisted. The engine speed is reduced rapidly by generating power when the engine speed is decelerated. This is because the energy of the engine 2 is regenerated.

  Further, by providing hysteresis between the first threshold value ΔGC1 and the second threshold value ΔGC2, and by providing hysteresis between the third threshold value ΔGC3 and the fourth threshold value ΔGC4, Control hunting is prevented.

  In the second determination unit 93, when the voltage BATTvolt of the battery 12 is within the predetermined range BC1 to BC4 (BC2 to BC3), the assist flag assist flag is set to T, and when the voltage is outside the predetermined range The assist flag assist flag is set to F.

  The first threshold value BC1, the second threshold value BC2, the third threshold value BC3, and the fourth threshold value BC4 are set to the voltage value BATTvolt. It is assumed that the first threshold value BC1, the second threshold value BC2, the third threshold value BC3, and the fourth threshold value BC4 increase in this order.

  The assist flag assist flag is set to T when the voltage value BATTvolt of the battery 12 becomes equal to or lower than the third threshold value BC3, and the assist flag assist flag is set to F when the voltage value BATTvolt of the battery 12 becomes equal to or higher than the fourth threshold value BC4. . When the voltage value BATTvolt of the battery 12 becomes equal to or higher than the second threshold value BC2, the assist flag assist flag is set to T. When the voltage value BATTvolt of the battery 12 becomes equal to or lower than the first threshold value BC1, the assist flag assist flag is set to F. To.

  As described above, only when the voltage BATTvolt of the battery 12 is within the predetermined range BC1 to BC4 (BC2 to BC3), the assist is performed when the voltage is low or high outside the predetermined range. This is to avoid adverse effects such as overcharge and complete discharge applied to the battery 12 by preventing the assist.

  Further, by providing a hysteresis between the first threshold value BC1 and the second threshold value BC2, and providing a hysteresis between the third threshold value BC3 and the fourth threshold value BC4, Control hunting is prevented.

  In the AND circuit 94, when the assist flag assist flag obtained by the first determination unit 92 and the assist flag assist flag obtained by the second determination unit 93 are both T, the assist flag assist flag is finally set. If the content is T, otherwise, the content of the assist flag assist flag is finally set to F.

  The assist flag determination unit 95 determines whether or not the content of the assist flag assist flag output from the assist presence determination unit 90 is T.

  In the generator motor command value switching unit 87, the content of the generator motor command value GENcom to be given to the inverter 13 is set to the target rotational speed according to whether or not the determination result of the assist flag determination unit 95 is T (F). Switch to target torque.

  The generator motor 11 is controlled by rotation speed control or torque control via the inverter 13.

  Here, the rotation speed control is control for adjusting the rotation speed of the generator motor 11 so that the target rotation speed can be obtained by giving the target rotation speed as the generator motor command value GENcom. Moreover, torque control is control which adjusts the torque of the generator motor 11 so that a target torque can be obtained by giving a target torque as the generator motor command value GENcom.

  In the modulation processing unit 97, the target rotational speed of the generator motor 11 is calculated and output. The generator motor torque calculation unit 68 calculates and outputs the target torque of the generator motor 11.

  That is, the modulation processing unit 97 outputs the rotation speed Ngencom that has been subjected to the modulation process according to the characteristic 97a with respect to the generator motor target rotation speed Ngencom obtained by the generator motor target rotation speed calculation unit 96. Rather than outputting the generator motor target speed Ngencom input from the generator motor target speed calculator 96 as it is, the generator motor target speed calculator 96 gradually increases the speed over time t. The input generator motor target rotational speed Ngencom is reached.

  With reference to FIG. 13 and FIG. 14, the effect when the modulation process is performed with respect to the case where the modulation process is not performed will be described.

  13 (a), 13 (b), 14 (a), and 14 (b) show torque diagrams in which the horizontal axis is the engine speed n and the vertical axis is the torque T as in FIGS. Yes.

  FIG. 13A is a diagram for explaining the movement of the governor 4 when there is no modulation processing at the time of engine acceleration, and FIG. 13B is a diagram for explaining the motion of the governor 4 when there is modulation processing at the time of engine acceleration. It is.

  FIG. 14A is a diagram for explaining the movement of the governor 4 when there is no modulation processing at the time of engine deceleration, and FIG. 14B is a diagram for explaining the motion of the governor 4 when there is modulation processing at the time of engine deceleration. It is.

  When a mechanical governor is used as the governor 4, there is a problem that the rotational speed designated by the governor 4 is delayed from the actual engine rotational speed.

  As shown in FIGS. 13A and 13B, it is assumed that the engine 2 is accelerated from the low rotation matching point P0 to the high rotation side when the load of the hydraulic pump 3 is large.

  In FIGS. 13A and 13B, P2 corresponds to the engine torque, and the total torque P3 of the engine 2 and the generator motor 11 is obtained by adding the assist torque to the engine torque. P1 corresponds to the pump absorption torque, and the sum of the pump absorption torque and the acceleration torque corresponds to the total torque P3.

  As shown in FIG. 13 (a), when there is no modulation process, an assist torque corresponding to the deviation between the target engine speed and the actual engine speed is generated. When the deviation is large, the assist torque by the generator motor 11 increases corresponding to the large deviation. For this reason, the engine 2 accelerates faster than the movement of the governor 4, and the actual rotational speed becomes larger than the rotational speed designated by the governor 4. When the engine 2 accelerates quickly, the fuel injection amount is reduced by adjusting the governor 4, and the engine torque is reduced. For this reason, although the engine 2 is assisted by the generator motor 11, the engine 2 becomes friction, and the acceleration of the engine 2 does not increase. For this reason, while reducing the fuel injection amount and reducing the engine torque, the engine 2 is lost and the engine 2 is accelerated, resulting in energy loss and the result that the engine 2 is not sufficiently accelerated.

  On the other hand, as shown in FIG. 13B, when the modulation process is present, the modulation process is performed on the target engine speed, and the deviation between the target engine speed and the actual engine speed becomes small. Accordingly, a small assist torque is generated in the generator motor 11. For this reason, the movement of the governor 4 follows the acceleration of the engine 2, and the rotational speed designated by the governor 4 matches the actual rotational speed.

  For this reason, energy loss is reduced and the engine 2 is sufficiently accelerated.

  Next, a case where the engine 2 is decelerated will be described.

  As shown in FIGS. 14A and 14B, it is assumed that the engine 2 is decelerated from the high rotation matching point P0 to the low rotation side when the load of the hydraulic pump 3 is large.

  14A and 14B, P2 corresponds to the engine torque, and the sum of the engine torque and the regenerative torque is the total torque P3 of the engine 2 and the generator motor 11 combined. P1 corresponds to the pump absorption torque, and the sum of the pump absorption torque and the deceleration torque corresponds to the total torque P3.

  As shown in FIG. 14A, when there is no modulation processing, regenerative torque is generated according to the deviation between the target engine speed and the actual engine speed. When the deviation is large, the regenerative torque by the generator motor 11 is increased corresponding to the large deviation. For this reason, the engine 2 decelerates faster than the movement of the governor 4, and the actual rotational speed becomes smaller than the rotational speed designated by the governor 4. When the engine 2 decelerates quickly, the fuel injection amount is increased by adjusting the governor 4 and the engine torque is increased. Therefore, the engine 2 decelerates while generating power with the generator motor 11 while increasing the torque. As a result, while the engine 2 increases the torque and the generator motor 11 collects the increased engine energy, the engine 2 is decelerated, and wasteful power generation is performed and fuel is wasted. .

  On the other hand, as shown in FIG. 14 (b), when the modulation process is present, the engine target speed is subjected to the modulation process, and the deviation between the engine target speed and the actual engine speed becomes small. Accordingly, a small regenerative torque is generated in the generator motor 11. For this reason, the movement of the governor 4 follows the deceleration of the engine 2, and the rotational speed designated by the governor 4 matches the actual rotational speed. For this reason, the torque of the engine 2 becomes negative, and the engine 2 decelerates while recovering the speed energy of the engine 2 by the generator motor 11. For this reason, the engine 2 can be decelerated efficiently without causing unnecessary energy consumption.

  In the generator motor torque calculation unit 68, the target torque Tgencom corresponding to the voltage BATTvolt is calculated based on the current voltage BATTvolt of the livestock generator 12 detected by the voltage sensor 15.

  The storage device has a functional relation 68a with hysteresis that the target torque Tgencom decreases according to the increase 68b of the voltage BATTvolt of the battery 12 and increases as the target torque Tgencom increases according to the decrease 68c of the voltage BATTvolt of the battery 12. Stored in table format. This functional relationship 68a is set in order to maintain the voltage value of the battery 12 within a desired range by adjusting the power generation amount of the generator motor 11.

  In the generator motor torque calculator 68, the target torque Tgencom corresponding to the current voltage BATTvolt of the battery 12 is output according to the functional relationship 68a.

  When the assist flag determination unit 95 determines that the content of the assist flag assit flag is T, the generator motor command value switching unit 87 is switched to the modulation processing unit 97 side and output from the modulation processing unit 97. The target rotational speed Ngencom is output to the inverter 13 as a generator motor command value GENcom, the rotational speed of the generator motor 11 is controlled, and the generator motor 11 performs an electric action or a power generation action.

  When the assist flag determining unit 95 determines that the content of the assist flag assit flag is F, the generator motor command value switching unit 87 is switched to the generator motor torque calculating unit 68 side, and the generator motor torque calculating unit 68 is switched. Is output to the inverter 13 as a generator motor command value GENcom, the torque of the generator motor 11 is controlled, and the generator motor 11 generates power.

  The pump absorption torque command value switching unit 88 determines the content of the pump target absorption torque T to be given to the control current calculation unit 67 according to whether or not the determination result of the assist flag determination unit 95 is T (F). The first pump target absorption torque Tpcom1 is switched to the second pump target absorption torque Tpcom2.

  The first pump target absorption torque Tpcom1 is calculated by the first pump target absorption torque calculator 66 (the same configuration as the pump absorption torque calculator shown in FIG. 4).

  That is, the first pump target absorption torque Tpcom1 is given as a torque value on the first target torque line L1 in the torque diagram of FIG. As described with reference to FIG. 10, the first target torque line L1 is set as a target torque line such that the target absorption torque Tpcom1 of the hydraulic pump 3 decreases as the engine target speed n decreases.

  The second pump target absorption torque Tpcom2 is calculated by the second pump target absorption torque calculation unit 85.

  In other words, the second pump target absorption torque Tpcom2 is a second target torque line in which the pump target absorption torque is larger in the low rotation region than the first target torque line L1 in the torque diagram of FIG. It is given as a torque value on L2.

  The first pump target absorption torque calculator 66 calculates the first pump target absorption torque Tpcom1 of the hydraulic pump 3 corresponding to the engine target speed ncom.

  In the storage device, a functional relationship 66a in which the first target absorption torque Tpcom1 of the hydraulic pump 3 increases in accordance with the increase in the engine target rotational speed ncom is stored in a data table format. This function 66a is a curve corresponding to the first target torque line L1 on the torque diagram shown in FIG. 9 (a) (FIG. 10).

  FIG. 9 (a) shows a torque diagram of the engine 2 as in FIG. 10, with the horizontal axis representing the engine speed n (rpm; rev / min) and the vertical axis representing the torque T (N · m). ing. The function 66a corresponds to the target torque line L1 on the torque diagram shown in FIG.

  In the first pump target absorption torque calculating unit 66, the first pump target absorption torque Tpcom1 corresponding to the current engine target rotational speed ncom is calculated according to the functional relationship 66a.

  The second pump target absorption torque calculation unit 85 calculates the second pump target absorption torque Tpcom2 of the hydraulic pump 3 corresponding to the generator motor rotation speed GENspd (engine actual rotation speed).

  In the storage device, a functional relationship 85a in which the second target absorption torque Tpcom2 of the hydraulic pump 3 changes according to the generator motor speed GENspd (engine actual speed) is stored in a data table format. The function 85a is a curve corresponding to the second target torque line L2 on the torque diagram shown in FIG. 9A, and the pump target absorption torque in the low rotation region with respect to the first target torque line L1. Has a characteristic of increasing. For example, the second target torque line L2 is a curve corresponding to an equal horsepower line, and the characteristic can be adopted so that the torque decreases as the engine speed increases.

  The second pump target absorption torque calculation unit 85 calculates the second pump target absorption torque Tpcom2 corresponding to the current generator motor rotation speed GENspd (engine actual rotation speed) according to the functional relationship 85a.

  When the assist flag determining unit 95 determines that the content of the assist flag assit flag is T, the pump absorption torque command value switching unit 88 is switched to the second pump target absorption torque calculating unit 85 side, and the second The second pump target absorption torque Tpcom2 output from the pump target absorption torque calculation unit 85 is output to the subsequent filter processing unit 89 as the pump target absorption torque Tpcom.

  When the assist flag determining unit 95 determines that the content of the assist flag assit flag is F, the pump absorption torque command value switching unit 88 is switched to the first pump target absorption torque calculating unit 66 side, and the first The first pump target absorption torque Tpcom1 output from the first pump target absorption torque calculator 66 is output to the subsequent filter processing unit 89 as the pump target absorption torque Tpcom.

  As described above, the pump absorption torque command value switching unit 88 switches the selection of the target absorption torques Tpcom1 and Tpcom2 of the hydraulic pump 3, that is, the target torque lines L1 and L2 in FIG.

  In the filter processing unit 89, when the selection of the target torque lines L1 and L2 is switched, the pump target absorption torque (second pump target absorption) on the target torque line before switching (for example, the second target torque line L2) is switched. A filter process for gradually changing from the torque Tpcom2) to the pump target absorption torque (first pump target absorption torque Tpcom1) on the target torque line after switching (first target torque line L1) is performed.

  That is, when the selection of the target torque lines L1 and L2 is switched, the filter processing unit 89 outputs the target torque value Tpcom that has been subjected to the filter processing according to the characteristic 89a. When the selection of the target torque lines L1 and L2 is switched, switching is performed from the pump target absorption torque (second pump target absorption torque Tpcom2) on the target torque line (for example, the second target torque line L2) before switching. Instead of switching to the pump target absorption torque (second pump target absorption torque Tpcom1) on the subsequent target torque line (first target torque line L1) as it is, it is gradually switched over over time t. Pump target absorption torque (second target torque line L2) pump target absorption torque (second pump target absorption torque Tpcom2) on the target torque line after switching (first target torque line L1) Smoothly reach the absorption torque (second pump target absorption torque Tpcom1).

  9A, the first pump target at the point H on the first target torque line L1 from the second pump target absorption torque Tpcom2 at the point G on the second target torque line L2. It gradually changes over time toward the absorption torque Tpcom2.

As a result, it is possible to suppress a shock applied to the operator and the vehicle body due to a sudden change in torque, and to eliminate a sense of incongruity in the operational feeling.

  The filter process may be performed in both cases where the determination result of the assist flag determination unit 95 is switched from T to F and when the determination result is switched from F to T. Filter processing may be performed only when it is performed. In particular, when the determination result of the assist flag determination unit 95 is switched from T to F and switched from the second target torque line L2 to the first target torque line L1, if the filter process is not performed, the torque decreases rapidly. In many cases, the operator feels uncomfortable. For this reason, when the determination result is switched from T to F and the second target torque line L2 is switched to the first target torque line L1, it is desirable to perform a filtering process.

  The pump target absorption torque Tpcom output from the filter processing unit 89 is given to the control current calculation unit 67 having the same configuration as that shown in FIG.

  In the control current calculator 67, a control current pc-epc corresponding to the pump target absorption torque Tpcom is calculated.

  In the storage device, a functional relationship 67a in which the control current pc-epc increases as the pump target absorption torque Tpcom increases is stored in a data table format.

  In the control current calculator 67, the control current pc-epc corresponding to the current pump target absorption torque Tpcom is calculated according to the functional relationship 67a.

  A control current pc-epc is output from the controller 6 to the pump control valve 5 to change the swash plate 3a of the hydraulic pump 3 via the servo piston. The pump control valve 5 prevents the product of the discharge pressure PRp (kg / cm 2) of the hydraulic pump 3 and the capacity q (cc / rev) of the hydraulic pump 3 from exceeding the pump absorption torque Tp com corresponding to the control current pc-epc. In addition, the tilt angle of the swash plate 3a of the hydraulic pump 3 is PC-controlled.

  Next, the effect of this embodiment will be described.

  According to this embodiment, as shown in FIG. 9 (a), the first target torque line L1 is set, in which the target absorption torque of the hydraulic pump 3 decreases as the engine target speed decreases. Further, a second target torque line L2 is set with respect to the first target torque line L1, which increases the pump target absorption torque in the low rotation range.

  Then, the engine speed is controlled so as to coincide with the engine target speed. For example, when it is determined that the load of the hydraulic pump 3 is small from the operation amount of each operation lever 41 to 44, the engine target rotation speed is set to a low rotation speed nD, and the hydraulic pump 3 is determined from the operation amount of each operation lever 41 to 44. When it is determined that the engine load is large, the engine target speed is set to a high speed nE.

  Then, it is determined whether or not the deviation between the target engine speed and the actual engine speed is equal to or greater than a predetermined threshold value, that is, whether or not the generator motor 11 should assist the engine 2.

  When the deviation between the engine target speed and the actual engine speed is not equal to or greater than a predetermined threshold value, the first target torque line L1 is selected, and the first target speed corresponding to the engine target speed is selected. The capacity of the hydraulic pump 3 is controlled so that the pump target absorption torque on the target torque line L1 is obtained.

  Therefore, when the engine target speed is set to the low speed nD, the governor 4 sets the upper limit torque at a point D that intersects the first target torque line L1 on the regulation line FeD corresponding to the engine target speed nD. As a value, the fuel injection amount is increased or decreased so that the engine 2 and the hydraulic pump absorption torque are balanced. Statically, matching is performed at a point D on the first target torque line L1.

  When the target engine speed is set to the high engine speed nE, the governor 4 sets an upper limit torque value at a point E that intersects the first target torque line L1 on the regulation line FeE corresponding to the engine target engine speed nE. The fuel injection amount is increased or decreased so that the engine 2 and the hydraulic pump absorption torque are balanced. Statically, matching is performed at a point E on the first target torque line L1.

  Therefore, when the assist by the generator motor 11 is not performed, the engine 2 is controlled along the target torque line L1 as in the comparative example, so that the fuel efficiency is improved, the pump efficiency and the engine efficiency are improved, the noise is reduced, and the engine stall is increased. Effects such as prevention can be obtained.

  When the deviation between the target engine speed and the actual engine speed is equal to or greater than a predetermined threshold value, the generator motor 11 is electrically operated. As a result of the generator motor 11 being electrically operated, the torque indicated by the broken line in FIG. 9A is added to the engine torque.

  When the threshold value is equal to or greater than the threshold value, the second target torque line L2 is selected so that the pump target absorption torque on the second target torque line L2 corresponding to the engine speed can be obtained. The capacity of the hydraulic pump 3 is controlled.

  This control will be described in comparison with a comparative example.

  Here, for example, a case is assumed where the operation lever 41 or the like is tilted from the neutral position in order to start excavation work. In this case, it is necessary to increase the engine speed from a low rotation to a high load matching point E of high rotation.

  In the case of the comparative example, the engine 2 accelerates along the path LN1 in FIG. In the initial stage of starting the excavation work, it is necessary to operate the work implement or the like while increasing the engine rotation (at the time of transition). In the case of the comparative example, although the responsiveness of the engine 2 is good, there is no assist by the generator motor 2 and no shift to the second target torque line L2, so that the hydraulic pump 3 is in an initial stage when the engine speed is increased. Absorption torque will be reduced. For this reason, the start of movement of the work implement is delayed with respect to the movement of the operation lever, causing a reduction in work efficiency and giving the operator an uncomfortable feeling of operation.

  When the assist by the generator motor 11 is added to the comparative example described above, the engine 2 is accelerated along the path LN2. In this case, since there is assistance by the generator motor 2, the absorption torque of the hydraulic pump 3 becomes larger at the initial stage when the engine speed is increased than in the comparative example. For this reason, the work machine starts to move faster than the operation lever, so that a reduction in work efficiency can be suppressed, and an uncomfortable feeling of operation given to the operator can be reduced. Therefore, as a modification of the present embodiment, it is possible to simply add the assist by the generator motor 11 to the comparative example.

  Furthermore, in the case of the present embodiment, the engine 2 accelerates along the path LN3 in FIG. According to the present embodiment, the point E is reached from the low rotation speed via the point F on the second target torque line L2. That is, immediately after the operation lever 41 is tilted, the hydraulic pump absorption torque immediately reaches a point F where the torque becomes high, so that the working machine starts to move faster than the operation lever moves. For this reason, the work implement can be instantaneously and powerfully moved without lagging the movement of the operation lever while accelerating the engine 2. This improves work efficiency and does not give the operator a sense of incongruity. If there is no assistance from the generator motor 11 (without the hatched portion shown in FIG. 9C) and the transition to the second target torque line L2 is attempted, the engine 2 may be overloaded. In this embodiment, on the premise of assist by the generator motor 11, the transition to the second target torque line L2 is guaranteed.

  As described above, according to this embodiment, it is possible to operate a work machine or the like with high responsiveness as intended by the operator while improving engine efficiency, pump efficiency, and the like.

(Example 2)
In the first embodiment described above, the description has been made on the assumption that the upper swing body of the construction machine 1 is swung by a hydraulic actuator (hydraulic motor). However, in the following, the upper swing body of the construction machine 1 is swung by an electric actuator. A second embodiment based on an electric turning system to be operated will be described.

  FIG. 15 is a configuration diagram of the second embodiment and shows a configuration of the construction machine 1 equipped with the electric turning system.

As shown in FIG. 15, similarly to the configuration of FIG. 3, a PTO shaft 10, a generator motor 11, a capacitor 12, an inverter 13, a rotation sensor 14, and a voltage sensor 15 are added to the comparative example of FIG. However, the electric motor 11 and the electric power generator 11 are operated in the same manner, but further, the constituent elements for rotating the upper swing body with the electric actuator (swing motor 103), that is, the generator motor controller 100, the current A sensor 101, a turning controller 102, a turning motor 103, and a turning speed sensor 105 are added.

  5, 6, 16, 17, 18, and 19 are control block diagrams showing processing contents performed by the controller 6.

  FIG. 16 is a diagram illustrating the control block 2 corresponding to FIG. 7 of the first embodiment, and the description of the same parts as those in FIG.

  As shown in FIG. 16, in the control block 2 of the second embodiment, the assist torque limit calculation unit 110, the third pump maximum absorption torque calculation unit 106, and the minimum value selection are compared with the control block 2 of the first embodiment. Is added, and generator motor command value switching units 187 and 287 are provided instead of the generator motor command value switching unit 87 in the control block 2 of the first embodiment, and the generator motor in the control block 2 of the first embodiment is provided. Instead of the torque calculator 68, a required power generation amount calculator 120 is provided.

  FIG. 17 is a block diagram illustrating an internal configuration of the assist presence / absence determination unit 90 corresponding to FIG. 8 of the first embodiment, and a description of the same parts as those in FIG.

FIG. 18 is a block diagram showing a detailed internal configuration of the assist torque limit calculation unit 110.

FIG. 19 is a block diagram illustrating a detailed internal configuration of the required power generation amount calculation unit 120.

In describing this embodiment, the engine torque assist action will be defined.

  The engine assist function is such that when the governor 4 and the fuel injection pump are adjusted to control the engine 2 so that the engine speed reaches a certain target engine speed, the actual engine engine speed quickly reaches the target engine speed. It means that torque is applied to the engine output shaft by the generator motor 11. Here, “adding torque” is not only to add shaft torque to quickly increase the engine speed when accelerating engine rotation, but also to quickly decrease engine speed when decelerating engine rotation. It is also used to include the case where the shaft torque is absorbed.

That is, the engine torque assist operation corresponds to the above-described first embodiment in which the generator motor 11 is electrically operated to assist the engine 2 and the generator motor 11 is caused to generate power to reversely assist the engine 2.

  As described in the first embodiment, the effect of the engine torque assist function is that the acceleration response of the engine is improved when the engine rotation is accelerated, the workability is improved, and the engine shaft torque is absorbed when the engine rotation is decelerated. As a result, the engine speed decreases rapidly, and the noise and vibration during deceleration of the engine speed are improved. In addition, since the engine shaft torque is absorbed when the engine speed is reduced, the rotational kinetic energy that the inertia around the engine output shaft has can be recovered, resulting in an improvement in energy efficiency. It is done.

On the other hand, “no engine torque assist operation” means that the generator motor 11 generates electric power and supplies its energy (electric power) to the battery 12 or directly to the swing motor 103 to drive the electric motor. It means that the revolving body is operated.

As described later, the generator motor controller 100 and the turning controller 102 execute the control to cause the engine torque assist action as described above or not to cause the engine torque assist action, as described later.

  As shown in FIG. 15, in the second embodiment, a turning motor 103 as an electric motor is connected to a drive shaft of the turning machinery 104, and the turning machinery 103 is driven to drive the turning machinery 104. The upper revolving body is driven and driven to swing through a swing pinion, a swing circle, and the like.

  The turning motor 103 performs a power generation operation and an electric operation. That is, the turning motor 103 operates as an electric motor and also operates as a generator. When the swing motor 103 operates as an electric motor, the upper swing body performs a swing operation, and when the upper swing body stops swinging, the torque of the upper swing body is absorbed and the swing motor 103 operates as a generator.

  The turning motor 103 is driven and controlled by the turning controller 102. The turning controller 102 is electrically connected to the battery 12 through a DC power supply line and is also electrically connected to the generator motor 100. The generator motor controller 100 is configured to include the function of the inverter 13 of the first embodiment (FIG. 3). The turning controller 102 and the generator motor controller 100 are controlled in accordance with a command output from the controller 6.

  The current supplied to the swing motor 103, that is, the swing load current SWGcurr indicating the load of the upper swing body is detected by the current sensor 101. The turning load current SWGcurr detected by the current sensor 101 is input to the controller 6.

  In the second embodiment, as shown in FIGS. 5 and 6, when the engine target speed ncom is selected by the minimum value selection unit 65 as in the first embodiment, the process proceeds to the control block 2 shown in FIG. Then, the processing described below is executed. Hereinafter, each control example will be described.

(Control example 1)
In the present control example 1, the required power generation amount calculation unit 120 calculates the required power generation amount Tgencom of the generator motor 11 according to the storage state of the battery 12.

  Then, in the assist presence / absence determination unit 90, it is determined whether the generator motor 11 is to perform the engine torque assist operation (determination result T) or whether the engine torque assist operation is not performed (determination result F).

When the assist presence / absence determination unit 90 determines that the generator motor 11 is to be subjected to engine torque assist (determination result T), the generator motor command value switching unit 187 is switched to the T side, that is, the modulation processing unit 97 side. Then, the generator motor 11 is caused to act as an engine torque assist. In this case, the generator motor speed command value (generator motor target rotational speed) Ngencom is output from the modulation processing unit 97 to the generator motor controller 100. In response to this, the generator controller 100 controls the rotational speed of the generator motor 11 so that the generator motor target rotational speed Ngencom is obtained, and causes the generator motor 11 to perform an electric torque action or an engine torque assist action. On the other hand, when the assist presence / absence determination unit 90 determines that the engine motor 11 does not perform the engine torque assist operation (determination result F), the generator motor command value switching unit 187 is switched to the F side, and the generator motor is 11 is turned off so that the engine torque assist operation is not performed, and the generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side. Power generation is performed so that a power generation amount corresponding to the required power generation amount Tgencom calculated by the required power generation amount calculation unit 120 is obtained. In this case, the required power generation amount Tgencom is output from the required power generation amount calculation unit 120 to the generator motor controller 100 as a generator motor torque command value (generator motor target torque). In response to this, the generator motor controller 100 controls the torque of the generator motor 11 so that the generator motor target torque Tgencom is obtained, and causes the generator motor 11 to generate power. In this case, the turning controller 102 performs control to supply the electric power generated by the generator motor 11 to the battery 12 or directly to the turning motor 103 to operate the electric upper turning body.

As described above, in the present control example 1, the generator motor 11 is configured to generate power corresponding to the required power generation amount without performing the engine torque assist function or performing the engine torque assist function depending on the necessity of the engine torque assist function. As a result, the amount of electricity stored in the battery 12 can be stably maintained in a target state at all times, and the operability of the work implement, particularly the upper swing body, can always be maintained at a high level.

(Control example 2)
In the present control example 2, the required power generation amount calculation unit 120 calculates the required power generation amount Tgencom of the generator motor 11 according to the storage state of the battery 12.

  In the first pump target absorption torque calculation unit 66, a first maximum torque line 66a indicating the maximum absorption torque that can be absorbed by the hydraulic pump 3 is set according to the engine target rotational speed.

  In the second pump target absorption torque calculation unit 85, a second maximum torque line 85a that increases the maximum absorption torque in the engine low rotation region is set with respect to the first maximum torque line 66a.

  Then, in the assist presence / absence determination unit 90, it is determined whether the generator motor 11 is to perform the engine torque assist operation (determination result T) or whether the engine torque assist operation is not performed (determination result F).

When the assist presence / absence determination unit 90 determines that the generator motor 11 is to be subjected to engine torque assist (determination result T), the pump absorption torque command value switching unit 88 is on the T side, that is, the second pump target absorption torque. The pump is switched to the calculation unit 85 side, the second maximum torque line 85a is selected as the maximum torque line, and the pump absorption torque on the second maximum torque line 85a corresponding to the current engine target rotational speed is the upper limit. The capacity of the hydraulic pump 3 is controlled so that the absorption torque can be obtained. On the other hand, when the assist presence / absence determination unit 90 determines that the generator motor 11 does not perform the engine torque assist operation (determination result F), the pump absorption torque command value switching unit 88 is on the F side, that is, the first pump target Switching to the absorption torque calculation unit 66 side, the first maximum torque line 66a is selected as the maximum torque line, and the pump absorption torque on the first maximum torque line 66a corresponding to the current engine target speed is set as the upper limit. The capacity of the hydraulic pump 3 is controlled so as to obtain the pump absorption torque. The pump capacity is controlled by outputting the control current pc-epc from the controller 6 to the pump control valve 5 and changing the swash plate 3a of the hydraulic pump 3 via the servo piston, as in the first embodiment. .

When the assist presence / absence determination unit 90 determines that the generator motor 11 is to be subjected to engine torque assist (determination result T), the generator motor command value switching unit 187 is switched to the T side, that is, the modulation processing unit 97 side. Then, the generator motor 11 is caused to act as an engine torque assist. In this case, the generator motor speed command value (generator motor target rotational speed) Ngencom is output from the modulation processing unit 97 to the generator motor controller 100. In response to this, the generator controller 100 controls the rotational speed of the generator motor 11 so that the generator motor target rotational speed Ngencom is obtained, and causes the generator motor 11 to perform an electric torque action or an engine torque assist action. On the other hand, when the assist presence / absence determination unit 90 determines that the engine motor 11 does not perform the engine torque assist operation (determination result F), the generator motor command value switching unit 187 is switched to the F side, and the generator motor is 11 is turned off so that the engine torque assist operation is not performed, and the generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side, and the required power generation amount calculation unit The generator motor 11 is caused to generate power so that a power generation amount corresponding to the required power generation amount Tgencom calculated at 120 is obtained. In this case, the required power generation amount Tgencom is output from the required power generation amount calculation unit 120 to the generator motor controller 100 as a generator motor torque command value (generator motor target torque). In response to this, the generator motor controller 100 controls the torque of the generator motor 11 so that the generator motor target torque Tgencom is obtained, and causes the generator motor 11 to generate power. In this case, the turning controller 102 performs control to supply the electric power generated by the generator motor 11 to the battery 12 or directly to the turning motor 103 to operate the electric upper turning body.

As described above, in the second control example, as in the first control example, depending on the necessity of the engine torque assist function, the engine torque assist function is performed or the engine torque assist function is not performed, and the power generation according to the required power generation amount is performed. Since it was made to perform with the generator motor 11, while being able to maintain stably the amount of electrical storage of the electrical storage device 12 always to the target state, the operativity of a working machine, especially an upper turning body can always be maintained at a high level.

Moreover, in the control example 2, while the engine torque assist action is performed by the generator motor 11,
With respect to the first maximum torque line 66a, the hydraulic pump 3 has a pump absorption torque whose upper limit is the pump absorption torque on the second maximum torque line 85a in which the maximum absorption torque increases in the engine low rotation region. Since the capacity is controlled, it is possible to increase the absorption torque of the hydraulic pump 3 at the initial stage when the engine speed is increased. For this reason, the working machine starts to move quickly with respect to the movement of the operation lever, so that a reduction in work efficiency can be suppressed, and the uncomfortable feeling of operation given to the operator can be reduced. As described in the first embodiment, if an attempt is made to perform control according to the second maximum torque line L2 without causing the generator motor 11 to perform the engine torque assist operation, the engine 2 may be overloaded. That is, if the capacity of the hydraulic pump 3 is controlled according to the second maximum torque line 85a without the engine torque assisting action, the hydraulic pump 3 absorbs torque exceeding the output of the engine alone, and the engine Not only can the engine speed not be increased, but the engine speed may decrease due to a high load, leading to an engine stall in the worst case. As described above, in the control example 2, the control according to the second maximum torque line 85a is guaranteed on the premise of the engine torque assist action by the generator motor 11.

(Control example 3)
In the control example 1 and the control example 2 described above, the assist presence / absence determination unit 90 specifically performs the determination as shown in FIG. That is, in the first determination unit 92, when the absolute value of the deviation Δgenspd between the generator motor target rotational speed Ngencom and the generator motor actual rotational speed GENspd exceeds a predetermined threshold, that is, the engine target rotational speed and the engine 2 When the absolute value of the deviation from the actual rotational speed is greater than or equal to a predetermined threshold value, it is determined that the generator motor 11 is to perform the engine torque assist operation, and the assist flag assist flag is set to T. On the other hand, when the absolute value of the deviation Δgenspd between the generator motor target rotational speed Ngencom and the generator motor actual rotational speed GENspd is below a predetermined threshold value, that is, the engine target rotational speed and the actual rotational speed of the engine 2 Is smaller than a predetermined threshold value, it is determined that the generator motor 11 is not subjected to engine torque assist, and the assist flag is set to F.

  When the rotational speed deviation Δgenspd becomes larger than a certain value with a sign plus, the generator motor 11 is electrically operated to assist the engine 2. As a result, when the current engine speed is different from the target speed, the engine speed rapidly increases toward the engine target speed. When the rotational speed deviation Δgenspd is a sign minus and increases to a certain degree or more, the generator motor 11 is caused to generate power and the engine 2 is counter-assisted. As a result, power is generated when the engine speed is decelerated, and the engine speed is rapidly reduced and the energy of the engine 2 is regenerated.

As described above, in the present control example 3, since a threshold value is provided for the deviation and it is determined whether or not the engine torque assist operation is performed, the control is stabilized. In other words, if the engine torque assist action is performed immediately when there is a deviation without setting a threshold for the deviation, the engine torque assist action is continued at an engine speed near the engine target speed. , Leading to energy loss. This is because the energy source for the engine torque assisting action is originally the energy of the engine 2, so that the engine torque assisting action always increases the energy loss by the efficiency of the generator motor 11. Generally, when the generator motor 11 is driven and generated with a small torque, the efficiency decreases.

(Control example 4)
In the control example 1 and the control example 2 described above, the assist presence / absence determination unit 90 specifically performs the determination as shown in FIG. That is, the second determination unit 93 determines that the generator motor motivation 11 is not to perform the engine torque assist operation when the voltage value BATTvolt of the battery 12, that is, the charged amount is equal to or less than the predetermined threshold value BC1, and the assist flag assist Set flag to F. As described above, by preventing the engine torque assist operation when the storage amount of the storage battery 12 is low, overdischarge of the storage battery 12 can be avoided, and a decrease in the life of the storage battery 12 can be avoided. In particular, the second embodiment is based on the assumption that the electric swing system is used, and therefore, energy storage energy is required to rotate the upper swing body. If the amount of stored energy is excessively reduced, the turning performance is adversely affected. By preventing the engine torque assist operation when the amount of electricity stored in the battery 12 is low, it is possible to avoid deterioration in turning performance due to a reduction in the amount of electricity stored.

(Control example 5)
In the control example 1 and the control example 2 described above, the assist presence / absence determination unit 90 specifically performs the determination as shown in FIG. That is, in the turning output calculation unit 95, the current output SWGpow of the turning motor 103 is calculated using the turning load current SWGcurr and the voltage value BATTvolt of the battery 12 by the following equation (5).

SWGpow = SWGcurr × BATTvolt × Kswg (5)
Kswg is a constant.

Then, in the third determination unit 96, when the current output SWGpow of the swing motor 103 is equal to or greater than the predetermined threshold value SC1, it is determined that the generator motor 11 is not operated with the engine torque assist, and the assist flag assist flag To F. Further, when the current output SWGpow of the swing motor 103 is equal to or less than the threshold value SC2 smaller than the threshold value SC1, it is determined that the generator motor motivation 11 is caused to perform the engine torque assist operation, and the assist flag assist flag is set to T To. Thus, by providing hysteresis between the threshold value SC1 and the threshold value SC2, control hunting is prevented.

In the AND circuit 94, the assist flag assist flag obtained by the first judging unit 92, the assist flag assist flag obtained by the second judging unit 93, and the assist flag assist obtained by the third judging unit 96 are used. When both flags are T, the content of the assist flag assist flag is finally set to T, and when either is F, the content of the assist flag assist flag is finally set to F.

On the other hand, as shown in FIG. 19, the required power generation amount calculation unit 120 generates the generator motor according to the voltage value BATTvolt of the battery 12, that is, the storage state of the battery 12, and the swing load current SWGcurr, that is, the drive state of the swing motor 103. Eleven required power generation amounts Tgencom are calculated.

In the case of the electric turning system, electric energy is required to turn the upper turning body. In order to turn the upper swing body at a high output, the stored energy of the battery 12 is not sufficient, and the generator motor 11 must generate electric power to supply power to the swing motor 103. This means that the required power generation amount calculation unit 120 considers not only the storage state (voltage value BATTvolt) of the battery 12 but also the drive state (turning load current SWGcurr) of the swing motor 11.

According to the present control example 5, when the current output SWGpow of the swing motor 103 is equal to or greater than the predetermined threshold value SC1, it is determined that the generator motor motivation 11 is not to perform the engine torque assist operation, and the engine torque assist operation is prohibited. On the other hand, the required power generation amount Tgencom of the generator motor 11 is calculated in consideration of not only the storage state of the battery 12 (voltage value BATTvolt) but also the drive state of the swing motor 6 (swing load current SWGcurr). Power generation according to Tgencom is performed by the generator motor 11, and the generated power is supplied to the turning motor 103. For this reason, it is possible to turn the upper turning body without lowering the turning performance.

(Control example 6)
As described above, when the rotational speed deviation Δgenspd is larger than a certain value by the sign plus, the generator motor speed command value (generator motor target rotational speed) Ngencom is output from the modulation processing unit 97 to the generator motor controller 100, In response to this, the generator controller 100 controls the rotational speed of the generator motor 11 so that the generator motor target rotational speed Ngencom is obtained, and causes the generator motor 11 to be electrically operated. That is, when the current engine speed is smaller than the engine target speed, the generator motor 11 is electrically operated, and the shaft torque of the engine 2 is added on the torque diagram of the engine 2 to increase the engine speed. The output torque of the generator motor 11 is controlled so that the engine speed is equal to the target engine speed.

When the rotation speed deviation Δgenspd is a sign minus and increases to a certain degree or more, a generator motor speed command value (generator motor target rotation speed) Ngencom is output from the modulation processing unit 97 to the generator motor controller 100, and the generator In response to this, the controller 100 controls the rotational speed of the generator motor 11 so that the generator motor target rotational speed Ngencom is obtained, and causes the generator motor 11 to generate power. That is, when the current engine speed is greater than the engine target speed, the generator motor 11 is caused to generate power, absorb the shaft torque of the engine 2 on the engine torque diagram, and decrease the engine speed. The output torque of the generator motor 11 is controlled so that the rotation speed is equal to the engine target rotation speed.

(Control example 7)
As described above, when the assist presence / absence determination unit 90 determines that the voltage value BATTvolt of the battery 12, that is, the amount of charge is equal to or less than the predetermined threshold value BC 1, the generator motor 11 is not allowed to perform the engine torque assist (determination result). F), the generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side, and the power generation amount corresponding to the required power generation amount Tgencom calculated by the required power generation amount calculation unit 120 is obtained. The generator motor 11 generates power so as to be obtained.

However, if the amount of electricity stored in the battery 12 reaches a threshold value or less, the engine torque assist operation is immediately prohibited, and the power generation operation corresponding to the required power generation amount is performed from the state where the engine torque assist operation is being performed. If it is suddenly switched to a state where the engine 2 is running, a sudden load may be applied to the output shaft of the engine 2. For this reason, the engine 2 cannot cope with the sudden load, the output of torque cannot catch up, and the engine speed may suddenly decrease. A sudden decrease in the engine speed leads to a decrease in the output of the work machine, which is undesirable in terms of work efficiency.

Therefore, in this control example 7, before switching from the state in which the engine torque assist operation is performed to the state in which the power generation operation according to the required power generation amount is performed, the upper limit value (torque limit) of the torque that can be generated by the generator motor 11 is set. Then, the value is gradually decreased in accordance with a decrease in the charged amount (voltage value BATTvolt) of the battery 12. Specifically, as shown in FIG. 18, in the calculation unit 111 of the assist torque limit calculation unit 110, the voltage value BATTvolt of the battery 12 is a second value that is smaller than the first predetermined value BD1 from the first predetermined value BD1. As the predetermined value BD2 is decreased, the torque upper limit value (generator motor torque limit) GENtrqlimit of the generator motor 11 is obtained as a value that is gradually reduced and output.

When it is determined that the generator motor 11 is to be subjected to engine torque assist (determination result T) and the generator motor command value switching unit 287 is switched to the T side, that is, the assist torque limit calculation unit 110 side, the assist torque limit calculation is performed. The generator motor torque limit GENtrqlimit is output from the unit 110 to the generator motor controller 100 as a limit value of the generator motor torque command value (generator motor target torque) Tgencom.

When it is determined that the engine torque assist operation is to be performed, the generator motor 11 operates by speed control so as to obtain the target rotational speed. The generator motor torque command value (generator motor target torque) Tgencom of the generator motor 11 is calculated as a result of the speed control loop.

The generator motor controller 100 controls the generator motor so that the generator motor torque command value (generator motor target torque) Tgencom calculated from the speed control loop does not exceed the generator motor torque limit GENtrqlimit calculated by the assist torque limit calculation unit 110. 11 to control the generator motor 11 to assist. That is, the torque of the generator motor 11 is controlled within the range of the torque upper limit value GENtrqlimit or less. Then, when the voltage value BATTvolt of the battery 12 becomes equal to or less than the predetermined threshold value BC1 and the generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side, the required power generation amount calculation unit 120. The generator motor 11 is caused to generate power so as to obtain a power generation amount corresponding to the required power generation amount Tgencom calculated in (1). In this case, the required power generation amount Tgencom is output from the required power generation amount calculation unit 120 to the generator motor controller 100 as a generator motor torque command value (generator motor target torque). In response to this, the generator motor controller 100 controls the torque of the generator motor 11 so that the generator motor target torque Tgencom is obtained, and causes the generator motor 11 to generate power. As described above, in the present control example 7, the upper limit value (torque limit) of the torque that can be generated by the generator motor 11 before switching from the state in which the engine torque assist operation is performed to the state in which the power generation operation according to the required power generation amount is performed. Since GENtrqlimit has been gradually decreased in accordance with the decrease in the storage amount (voltage value BATTvolt) of the battery 12, the engine torque assist operation is changed to the state in which the power generation operation according to the required power generation amount is performed. The change in the power generation torque of the generator motor 11 at the time of switching becomes smooth, and it can be avoided that the engine speed decreases during this switching.

(Control example 8)
In this control example 8, the following control is performed by the calculation unit 111 of the assist torque limit calculation unit 110 in the control example 7 described above. That is, as the voltage value BATTvolt of the battery 12 decreases from the first predetermined value BD1 to the second predetermined value BD2 smaller than the first predetermined value BD1, the torque upper limit value (generator motor torque limit) of the generator motor 11 While the GENtrqlimit is obtained and outputted as a value that is gradually reduced, when the torque upper limit GENtrqlimit once reduced is increased, the voltage value BATTvolt of the capacitor 12 is changed from the third predetermined value BD3 to the third value BDtrqlimit. The torque upper limit value (generator motor torque limit) GENtrqlimit of the generator motor 11 is obtained as a value that gradually increases as the fourth predetermined value BD4 larger than the predetermined value BD3 is increased, and is output.

Thus, by providing hysteresis in the way of changing the generator motor torque limit GENtrqlimit, the control can be performed stably.

(Control example 9)
As described above, when the assist presence / absence determination unit 90 determines that the current output SWGpow of the turning motor 103 is equal to or greater than the predetermined threshold value SC1, the generator motor 11 is not allowed to act on the engine torque (determination result F). The generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side, and a power generation amount corresponding to the required power generation amount Tgencom calculated by the required power generation amount calculation unit 120 is obtained. Thus, the generator motor 11 generates power.

Here, as in the control example 7, when the current output SWGpow of the turning motor 103 reaches a predetermined threshold value SC1 or more, the engine torque assist operation is immediately prohibited and requested from the state where the engine torque assist operation is performed. If the power generation action corresponding to the amount of power generation is suddenly switched, a sudden load may be applied to the output shaft of the engine 2. For this reason, the engine 2 cannot cope with the sudden load, the output of torque cannot catch up, and the engine speed may suddenly decrease. A sudden decrease in the engine speed leads to a decrease in the output of the work machine, which is undesirable in terms of work efficiency.

In Control Example 9, as in Control Example 7, the upper limit value of the torque that can be generated by the generator motor 11 before switching from the state in which the engine torque assist operation is performed to the state in which the power generation operation according to the required power generation amount is performed. (Torque limit) is gradually made smaller as the current output SWGpow of the swing electric motor 11 increases.

Specifically, as shown in FIG. 18, in the turning output calculation unit 112 of the assist torque limit calculation unit 110, the current output SWGpow of the turning motor 103 is expressed by the above-described equation (5) (SWGpow = SWGcurr × BATTvolt × Kswg). Next, in the calculation unit 113, as the current output SWGpow of the swing motor 103 increases from the first predetermined value SD1 to a second predetermined value SD2 that is larger than the first predetermined value SD1, the generator motor The torque upper limit value (generator motor torque limit) GENtrqlimit of 11 is obtained as a value that is gradually reduced and output.

The smaller value of the torque upper limit value GENtrqlimit determined by the calculation unit 111 and the torque upper limit value GENtrqlimit determined by the calculation unit 113 is selected by the minimum value selection unit 114, and the final torque upper limit value (generator motor) The torque limit GENtrqlimit) is output from the assist torque limit calculation unit 110.

When it is determined that the generator motor 11 is to be subjected to engine torque assist (determination result T) and the generator motor command value switching unit 287 is switched to the T side, that is, the assist torque limit calculation unit 110 side, the assist torque limit calculation is performed. The generator motor torque limit GENtrqlimit is output from the unit 110 to the generator motor controller 100 as a limit value of the generator motor torque command value (generator motor target torque) Tgencom.

When it is determined that the engine torque assist operation is to be performed, the generator motor 11 operates by speed control so as to obtain the target rotational speed. The generator motor torque command value (generator motor target torque) Tgencom of the generator motor 11 is calculated as a result of the speed control loop.

The generator motor controller 100 controls the generator motor so that the generator motor torque command value (generator motor target torque) Tgencom calculated from the speed control loop does not exceed the generator motor torque limit GENtrqlimit calculated by the assist torque limit calculation unit 110. 11 to control the generator motor 11 to assist. That is, the torque of the generator motor 11 is controlled within the range of the torque upper limit value GENtrqlimit or less.

When the current output SWGpow of the swing motor 103 becomes equal to or greater than the predetermined threshold value SC1, and the generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side, the required power generation amount calculation is performed. The generator motor 11 generates power so that a power generation amount corresponding to the required power generation amount Tgencom calculated by the unit 120 is obtained. In this case, the required power generation amount Tgencom is output from the required power generation amount calculation unit 120 to the generator motor controller 100 as a generator motor torque command value (generator motor target torque). In response to this, the generator motor controller 100 controls the torque of the generator motor 11 so that the generator motor target torque Tgencom is obtained, and causes the generator motor 11 to generate power. As described above, in this control example 9, the upper limit value (torque limit) of the torque that can be generated by the generator motor 11 before switching from the state in which the engine torque assist operation is performed to the state in which the power generation operation according to the required power generation amount is performed. Since GENtrqlimit is gradually decreased as the current output SWGpow of the swing motor 103 increases, when the engine torque assist operation is switched to the power generation operation corresponding to the required power generation amount The change in the generated torque of the generator motor 11 becomes smooth, and it can be avoided that the engine speed decreases during this switching.
(Control example 10)
In this control example 10, the following control is performed by the calculation unit 113 of the assist torque limit calculation unit 110 in the control example 9 described above. That is, as the current output SWGpow of the swing motor 103 increases from the first predetermined value SD1 to the second predetermined value SD2 that is larger than the first predetermined value SD1, the torque upper limit value (generator motor torque) of the generator motor 11 is increased. Limit) When GENtrqlimit is obtained and output as a value that is gradually reduced, while the torque upper limit GENtrqlimit once reduced is increased, the current output SWGpow of the swing motor 103 is a third predetermined value SD3. To the fourth predetermined value SD4 smaller than the third predetermined value SD3, the torque upper limit value (generator motor torque limit) GENtrqlimit of the generator motor 11 is obtained as a value that is gradually increased and output. The

Thus, by providing hysteresis in the way of changing the generator motor torque limit GENtrqlimit, the control can be performed stably.

(Control Example 11)
As described above, when the assist presence / absence determination unit 90 determines that the voltage value BATTvolt of the battery 12 is equal to or lower than the predetermined threshold value BC1, or the current output SWGpow of the swing motor 103 is equal to or higher than the predetermined threshold value SC1. When it is determined, it is determined that the generator motor 11 is not allowed to act on the engine torque (determination result F), and the generator motor command value switching unit 287 is switched to the F side, that is, the required power generation amount calculation unit 120 side, and the request is made. The generator motor 11 generates power so that a power generation amount corresponding to the required power generation amount Tgencom calculated by the power generation amount calculation unit 120 is obtained.

Here, when the voltage value BATTvolt of the battery 12 reaches a predetermined threshold value BC1 or less, or when the current output SWGpow of the swing motor 103 reaches a predetermined threshold value SC1 or more, the engine torque assist operation is immediately prohibited. If the engine torque assist operation is suddenly switched to the power generation operation corresponding to the required power generation amount, a sudden load may be applied to the output shaft of the engine 2. For this reason, the engine 2 cannot cope with the sudden load, the output of torque cannot catch up, and the engine speed may suddenly decrease. A sudden decrease in the engine speed leads to a decrease in the output of the work machine, which is undesirable in terms of work efficiency.

In the present control example 11, instead of implementing the control example 7, the control example 8, the control example 9 and the control example 10, or together with the implementation of each of these control examples, the required power generation amount from the state in which the engine torque assist is being applied. Immediately after switching to the state in which the power generation action according to the operation is performed, control is performed to gradually change the power generation torque of the generator motor 11 from the torque at the end of the assist to the power generation torque corresponding to the required power generation amount of the generator motor 11. This avoids a sudden drop in engine speed during the switching.

Specifically, as shown in FIG. 19, in the calculation unit 121 of the required power generation amount calculation unit 120, the voltage value BATTvolt of the battery 12 is a second value that is smaller than the first predetermined value BE1 from the first predetermined value BE1. As the predetermined power value BE2 decreases, the required power generation output P is obtained and output as a value that gradually increases from zero output to the power generation output Pmax corresponding to the required power generation amount of the generator motor 11. Here, when the required power generation output P once increased is decreased, the voltage value BATTvolt of the battery 12 is increased from the third predetermined value BE3 to the fourth predetermined value BE4 which is larger than the third predetermined value BE3. Accordingly, the required power generation output P is obtained as a value that gradually decreases and is output.

Thus, by giving hysteresis to the way of changing the required power generation output P, the control is stably performed.

On the other hand, in the turning output calculation unit 122, the current output SWGpow of the turning motor 103 is obtained by using the turning load current SWGcurr and the voltage value BATTvolt of the battery 12 as described above (5) (SWGpow = SWGcurr × BATTvolt × Kswg). Is required. Next, in the calculation unit 123, as the current output SWGpow of the swing motor 103 increases from the first predetermined value SE1 to the second predetermined value SE2 that is larger than the first predetermined value SE1, the required power generation output P is increased. It is obtained and output as a value that is gradually increased from zero output to the power generation output Pmax corresponding to the required power generation amount of the generator motor 11. Here, when the required power generation output P once increased is decreased, the current output SWGpow of the swing motor 103 is changed from the third predetermined value SE3 to the fourth predetermined value SE4 smaller than the third predetermined value SE3. The required power generation output P is obtained as a value that gradually decreases as the power decreases, and is output.

Thus, by giving hysteresis to the way of changing the required power generation output P, the control is stably performed.

The larger value of the required power generation output P obtained by the calculation unit 121 and the required power generation output P obtained by the calculation unit 123 is selected by the maximum value selection unit 124, and as the final required power generation output Pgencom, It is added to the generator motor required power generation torque calculator 125. The generator motor required power generation torque calculating unit 125 calculates the generator motor required power generation torque Tgencom by the following equation (6) using the generator motor rotation speed GENspd and the required power generation output Pgencom.

Tgencom = Pgencom ÷ GENspd × Kgen (6)
Kgen is a constant.

  From the required power generation amount calculation unit 120, the generator motor required power generation torque Tgencom finally obtained by the above equation (6), that is, the power generation torque of the generator motor 11 is gradually generated from zero torque according to the required power generation amount of the generator motor. The required power generation torque Tgencom that increases the torque is output.

When the voltage value BATTvolt of the battery 12 reaches a predetermined threshold value BC1 or less, or when the current output SWGpow of the swing motor 103 reaches a predetermined threshold value SC1 or more, the generator motor command value switching unit 287 is switched to the F side. That is, it is switched to the required power generation amount calculation unit 120 side.

Immediately after this switching, as described above, the required power generation torque for gradually increasing the power generation torque of the generator motor 11 from zero torque to the power generation torque corresponding to the required power generation amount of the generator motor 11, that is, the required power generation amount Tgencom is the generator motor torque. It is output to the generator motor controller 100 as a command value (generator motor target torque). In response to this, the generator motor controller 100 controls the torque of the generator motor 11 so that the generator motor target torque Tgencom is obtained, and causes the generator motor 11 to generate power.

As described above, in this control example 11, immediately after switching from the state where the engine torque assist operation is performed to the state where the power generation operation according to the required power generation amount is performed, the power generation torque of the generator motor 11 is gradually increased from zero torque to the generator motor. Since the control to increase the power generation torque corresponding to the required power generation amount of 11 is performed, the generator motor at the time of switching from the state where the engine torque assist operation is performed to the state where the power generation operation corresponding to the required power generation amount is performed Therefore, it is possible to avoid a decrease in engine speed at the time of switching.

(Control example 12)
In the control examples 7, 8, 9, and 10, the control for gradually decreasing the torque limit value of the generator motor 11 during the engine torque assist operation has been described.

However, if the control for gradually decreasing the torque upper limit value (torque limit value) of the generator motor 11 during the engine torque assist operation is performed, the force for assisting the engine 2 gradually decreases. The acceleration of the engine 2 is deteriorated when switching from the operated state to the state where the power generation operation corresponding to the required power generation amount is performed.

Therefore, in this control example 12, the assist force of the engine 2 is controlled by controlling the capacity of the hydraulic pump 3 so that the maximum absorption torque of the hydraulic pump 3 is gradually reduced as the torque upper limit value of the generator motor 11 decreases. The absorption torque of the hydraulic pump 3 is reduced in accordance with the decrease of the engine speed, and the deterioration of the engine speed acceleration accompanying the decrease of the assist force of the engine 2 is avoided.

That is, as shown in FIG. 16, the generator torque limit GENtrqlimit is output from the assist torque limit calculator 110 to the third pump maximum absorption torque calculator 106 as the torque upper limit value Tgencom2 of the generator motor 11. . In the third pump maximum absorption torque calculation unit 106, the maximum absorption torque (third pump maximum absorption torque) Tpcommax of the hydraulic pump 3 is gradually decreased as the torque upper limit value Tgencom2 of the generator motor 11 decreases. The maximum torque line L3 is stored in a data table format as a functional relationship 106a between the torque upper limit value Tgencom2 and the third pump maximum absorption torque Tpcommax. In the third pump maximum absorption torque calculation unit 106, a third pump maximum absorption torque Tpcommax corresponding to the current torque upper limit value Tgencom2 of the generator motor 11 is calculated according to the functional relationship 106a.

On the other hand, the first pump maximum absorption torque (first pump target absorption torque) Tpcom1 is calculated by the first pump target absorption torque calculator 66 on the first maximum torque line (first target torque line) L1. The value is calculated according to the function relation 66a.

  The second pump maximum absorption torque (second pump target absorption torque) Tpcom2 is calculated by the second pump target absorption torque calculation unit 85 on the second maximum torque line (second target torque line) L2. The value is calculated according to the functional relationship 85a.

  The minimum value selection unit 107 selects a pump maximum absorption torque value which is smaller between the current third pump maximum absorption torque Tpcommax and the current second pump maximum absorption torque Tpcom2, and outputs a pump absorption torque command value. It is output to the T side terminal of the switching unit 88.

The current first pump maximum absorption torque Tpcom is applied to the F-side terminal of the pump absorption torque command value switching unit 88.

If the assist flag determination unit 95 determines that the content of the assist flag assit flag is T, the pump absorption torque command value switching unit 88 is switched to the minimum value selection unit 107 side, and the second pump target absorption torque calculation is performed. The smaller one of the current second pump maximum absorption torque Tpcom2 output from the unit 85 and the current third pump maximum absorption torque Tpcommax output from the third pump maximum absorption torque calculation unit 106 is The pump maximum absorption torque Tpcom is output to the subsequent filter processing unit 89.

When the assist flag determining unit 95 determines that the content of the assist flag assit flag is F, the pump absorption torque command value switching unit 88 is switched to the first pump target absorption torque calculating unit 66 side, and the first The current first pump maximum absorption torque Tpcom1 output from one pump target absorption torque calculation unit 66 is output to the subsequent filter processing unit 89 as the pump maximum absorption torque Tpcom. Thereafter, the filter processing unit 89 performs the above-described filter processing, the control current calculation unit 67 outputs the control current pc-epc to the pump control valve 5, and the swash plate 3a of the hydraulic pump 3 is adjusted. That is, when the power generation operation is performed, the first pump maximum absorption torque Tpcom1 determined from the first maximum torque line L1 irrespective of the magnitude of the third pump maximum absorption torque Tpcommax determined from the third maximum torque line L3. Is selected, and the capacity of the hydraulic pump 3 is controlled using the first pump maximum absorption torque Tpcom1 as the upper limit Tpcom of the pump absorption torque. On the other hand, when the engine torque assist operation is performed, the second pump maximum absorption torque Tpcom2 determined from the second maximum torque line L2 and the third pump maximum absorption torque Tpcommax determined from the third maximum torque line L3 are smaller. Is selected, and the capacity of the hydraulic pump 3 is controlled using the smaller pump maximum absorption torque as the upper limit Tpcom of the pump absorption torque.

As described above, according to this control example, the capacity of the hydraulic pump 3 is controlled so that the maximum absorption torque of the hydraulic pump 3 is gradually reduced as the torque upper limit value of the generator motor 11 is reduced. When the torque assist operation is switched to the power generation operation corresponding to the required power generation amount, the absorption torque of the hydraulic pump 3 decreases in accordance with the decrease in the assist force of the engine 2 and the shaft torque of the engine 2 Thus, the change in the engine speed becomes smooth, and the deterioration of the engine speed acceleration accompanying the decrease in the assist force of the engine 2 can be avoided.

(Control Example 13)
As described above, at the time of switching between the state in which the engine torque assist operation is performed and the state in which the power generation operation according to the required power generation amount is performed, the selection of the maximum absorption torque of the hydraulic pump 3 is the second pump maximum It switches between the absorption torque Tpcom2 or the third pump maximum absorption torque Tpcommax and the first pump maximum absorption torque Tpcom1. For this reason, at the time of switching, due to a sudden change in pump absorption torque, the load applied to the output shaft of the engine 2 may change suddenly, and the engine speed may decrease.

Therefore, in this control example, when the selection of the maximum absorption torque of the hydraulic pump 3 is switched, control is performed to gradually change from the pump maximum absorption torque before switching to the pump maximum absorption torque after switching. Thus, a sudden change in the load applied to the output shaft of the engine 2 at the time of switching is prevented, and a decrease in the engine speed is avoided.

That is, as shown in FIG. 16, when the selection of the maximum torque line is switched between the second maximum torque line L2 or the third maximum torque line L3 and the first maximum torque line L1, the filter processing unit In 89, the maximum torque value Tpcom is gradually changed according to the characteristic 89a in which the maximum torque value Tpcom changes with the passage of time t. The characteristic 89a has a curve corresponding to the time constant τ. Thus, from the pump maximum absorption torque (third pump maximum absorption torque Tpcommax) on the maximum torque line before switching (for example, the third target torque line L3), the maximum torque line after switching (first maximum torque line). L1) The pump maximum absorption torque (first pump maximum absorption torque Tpcom1) on the maximum torque line (for example, the third target torque line L3) before switching is not directly switched to the pump maximum absorption torque (first pump maximum absorption torque Tpcom1). 3 gradually from the pump maximum absorption torque Tpcommax (3) to the pump maximum absorption torque (first pump maximum absorption torque Tpcom1) on the maximum torque line (first maximum torque line L1) after switching. It will change smoothly. The movement on the torque diagram is the same as described above with reference to FIG.

As a result, the load applied to the output shaft of the engine 2 is suddenly changed due to a sudden change in the pump absorption torque at the time of switching between the state in which the engine torque assist operation is performed and the state in which the power generation operation is performed according to the required power generation amount. It can be avoided that the engine speed decreases.

  The filter processing described above may be performed in both cases where the determination result of the assist flag determination unit 95 is switched from T to F, and when the determination result is switched from F to T. Filter processing may be performed only when switching is performed.

(Control example 14)
In the above control example 13, the time constant τ when changing from the pump maximum absorption torque before switching to the pump maximum absorption torque after switching is such that the pump maximum absorption torque before switching is higher than the pump maximum absorption torque after switching. It is desirable to set a larger value when the pump maximum absorption torque before switching is larger than the pump maximum absorption torque after switching, rather than when it is small.

  This is because when the time constant τ is uniformly set to a large value, when the pump maximum absorption torque is switched from a small state to a large state, the time constant of the change in the pump maximum absorption torque is large. Because it becomes dull.

FIG. 1 is a configuration diagram of a comparative example. FIG. 2 is a torque diagram used to explain the prior art. FIG. 3 is a configuration diagram of the first embodiment. FIG. 4 is a control block diagram of a comparative example. FIG. 5 is a control block diagram of the first embodiment. FIG. 6 is a control block diagram common to the comparative example and the first embodiment. FIG. 7 is a control block diagram of the first embodiment. FIG. 8 is a control block diagram of the first embodiment. FIGS. 9A, 9B, and 9C are torque diagrams used to describe the example. FIG. 10 is a torque diagram used for explaining a comparative example. FIG. 11 is a diagram illustrating pump output limit values corresponding to each work pattern. FIG. 12 is a diagram for explaining parameter changes during work of the construction machine. FIGS. 13A and 13B are diagrams for explaining the modulation processing during engine acceleration. FIGS. 14A and 14B are diagrams for explaining the modulation process during engine deceleration. FIG. 15 is a configuration diagram of the second embodiment and is a diagram illustrating a configuration of the construction machine 1 equipped with the electric turning system. FIG. 16 is a control block diagram showing the contents of processing performed by the controller 6. FIG. 17 is a control block diagram showing the contents of processing performed by the controller 6. FIG. 18 is a control block diagram showing the contents of processing performed by the controller 6. FIG. 19 is a control block diagram showing details of processing performed by the controller 6.

  2 Engine 3 Hydraulic pump 5 Pump control valve 6 Controller 11 Generator motor 31-36 Hydraulic actuator 41-44 Operation lever 103 Turning motor

Claims (10)

A hydraulic pump driven by an engine;
A hydraulic actuator to which pressure oil discharged from the hydraulic pump is supplied;
A generator motor connected to the output shaft of the engine;
A battery that accumulates the power generated by the generator motor and supplies power to the generator motor;
Calculation means for calculating the required power generation amount of the generator motor so that the required power generation amount decreases in accordance with the increase in the voltage of the capacitor, and the required power generation amount increases in accordance with the decrease in the voltage of the capacitor .
Engine target speed setting means for setting a target engine speed;
Maximum torque line setting means for setting a maximum torque line indicating the maximum absorption torque that can be absorbed by the hydraulic pump according to the engine target speed,
A speed control means for controlling the engine speed so that the engine speed matches the current engine target speed;
Capacity control means for controlling the capacity of the hydraulic pump so as to obtain a pump absorption torque whose upper limit is the pump absorption torque on the maximum torque line corresponding to the current target engine speed;
At least when the current voltage of the capacitor is within a predetermined range, the generator motor is operated with an engine torque assist, or the current voltage of the capacitor becomes a low voltage or a high voltage outside the predetermined range. Determining means for determining whether or not the engine torque assist operation is to be performed,
When it is determined by the determination means that the generator motor is to perform the engine torque assist operation, the generator motor is operated to perform the engine torque assist, and when it is determined that the generator motor is not to perform the engine torque assist operation, the generator motor is An engine, a hydraulic pump, and a generator motor control device, comprising: a generator motor control means for generating power according to the amount. The judging means is
When the absolute value of the deviation between the engine target speed and the actual engine speed is greater than or equal to a predetermined threshold value, it is determined that the generator motor is to be acted on by the engine torque, and the engine target speed and the engine 2. The engine according to claim 1 , wherein when the absolute value of the deviation from the actual rotational speed is smaller than a predetermined threshold value, the generator motor is determined not to act as an engine torque assist. , Hydraulic pump and generator motor control device. A storage amount calculating means for calculating a storage amount that the capacitor is currently storing;
The determination means includes
3. The engine, hydraulic pump, and generator motor control according to claim 2 , wherein when the calculated amount of stored electricity is equal to or less than a predetermined threshold value, the generator motor is determined not to perform engine torque assist. apparatus. A turning electric motor for turning the upper turning body of the construction machine;
A turning operation means for turning the upper turning body;
Control means for driving and controlling the swing motor in accordance with the turning operation by the turning operation means;
Output calculation means for calculating the current output of the swing motor;
Computation means for computing the required power generation amount of the generator motor according to the storage state of the capacitor and the drive state of the swing motor,
The determination means includes
The engine, the hydraulic pump, and the generator motor according to claim 2 , wherein when the current output of the swing motor is equal to or greater than a predetermined threshold value, the generator motor is determined not to perform an engine torque assist operation. Control device. When the current engine speed is smaller than the engine target speed, the generator motor control means adds the shaft torque of the engine on the engine torque diagram so that the engine speed is equal to the engine target speed. The output torque of the generator motor is controlled so that the engine speed is the same. If the current engine speed is greater than the target engine speed, the engine speed is absorbed by absorbing the engine shaft torque on the engine torque diagram. 5. The engine, hydraulic pump, and generator motor control apparatus according to claim 1, wherein the output torque of the generator motor is controlled so that the number of rotations is equal to the engine target speed. . Torque control means for controlling the torque of the generator motor within a range of a torque upper limit value or less during engine torque assist operation of the generator motor;
Torque upper limit value setting means for gradually reducing the torque upper limit value as the amount of electricity stored in the capacitor decreases from the first predetermined value to a second predetermined value smaller than the first predetermined value. The engine, hydraulic pump, and generator motor control device according to claim 1 . Torque control means for controlling the torque of the generator motor within a range of a torque upper limit value or less during engine torque assist operation of the generator motor;
The torque upper limit value is gradually reduced as the amount of electricity stored in the battery decreases from the first predetermined value to a second predetermined value smaller than the first predetermined value, while the torque upper limit value once reduced. Is increased, the torque upper limit value gradually increases as the storage amount of the battery increases from the third predetermined value to the fourth predetermined value that is larger than the third predetermined value. An engine, a hydraulic pump, and a generator motor control device according to claim 1 , further comprising: a value setting unit. Torque control means for controlling the torque of the generator motor within a range of a torque upper limit value or less during engine torque assist operation of the generator motor;
Torque upper limit setting means for gradually decreasing the torque upper limit as the current output of the swing motor increases from a first predetermined value to a second predetermined value greater than the first predetermined value. The control device for an engine, a hydraulic pump, and a generator motor according to claim 4 or 5 . Torque control means for controlling the torque of the generator motor within a range of a torque upper limit value or less during engine torque assist operation of the generator motor;
As the current output of the swing motor increases from the first predetermined value to the second predetermined value that is larger than the first predetermined value, the torque upper limit value is gradually decreased while the torque once reduced When increasing the upper limit value, the torque upper limit value is gradually increased as the current output of the swing motor decreases from the third predetermined value to the fourth predetermined value smaller than the third predetermined value. The engine, hydraulic pump, and generator motor control device according to claim 4 or 5, further comprising: The generator motor control means is
Immediately after switching the generator motor from the engine torque assist operation to the power generation operation, control is performed so that the power generation torque of the generator motor is gradually changed from the torque at the end of the assist to the power generation torque corresponding to the required power generation amount of the generator motor. The engine, hydraulic pump, and generator motor control device according to claim 1, wherein

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