KR101630457B1 - Power control apparatus for construction machinery - Google Patents
Power control apparatus for construction machinery Download PDFInfo
- Publication number
- KR101630457B1 KR101630457B1 KR1020090130426A KR20090130426A KR101630457B1 KR 101630457 B1 KR101630457 B1 KR 101630457B1 KR 1020090130426 A KR1020090130426 A KR 1020090130426A KR 20090130426 A KR20090130426 A KR 20090130426A KR 101630457 B1 KR101630457 B1 KR 101630457B1
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- engine
- horsepower
- hydraulic pump
- control unit
- pressure
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- Operation Control Of Excavators (AREA)
- Control Of Vehicle Engines Or Engines For Specific Uses (AREA)
Abstract
An apparatus for controlling power of a construction machine according to the present invention includes an engine (10) connected to a hydraulic pump (20) to drive the hydraulic pump (20); And an engine load ratio defined by a ratio of a load torque of the engine to an engine maximum torque calculated from the input engine target rotation speed, and wherein the engine rotation speed command value is calculated based on the engine load ratio so that the engine is driven at the target rotation speed, And outputs the calculated value to the engine.
Engine rotation speed, target rotation speed, hydraulic pump, horsepower control, hydraulic shock, soot, vibration
Description
BACKGROUND OF THE
Generally, a construction machine such as an excavator drives a plurality of working devices such as a boom, an arm, and a bucket by using hydraulic oil discharged from a variable displacement hydraulic pump directly connected to the engine.
The discharge flow rate of these hydraulic pumps is controlled by various parameters to meet various conditions such as efficiency of operation and fuel consumption.
More specifically, a method of controlling a hydraulic pump includes a work flow control for controlling a discharge flow rate in accordance with an operation signal inputted from an operation unit, and a flow control for controlling the flow rate of the hydraulic pump, according to the discharge pressure of the hydraulic pump, A constant horse power control for controlling the discharge flow rate, and a power shift control for controlling the discharge flow rate of the hydraulic pump depending on the load state of the engine.
In order to achieve the above-described control method, a hydraulic pump is provided with a regulator. The regulator includes a work flow rate controller for controlling the work flow rate, an equal horsepower controller for controlling the horsepower, And a horsepower control unit for the vehicle. The working flow control unit receives the center bypassed negative pressure, the pilot pressure of the operation unit, or the load sensing pressure of each actuator, and controls the discharge flow rate of the hydraulic pump. The equal horsepower regulating unit receives the discharge pressure (load pressure) of the hydraulic pump and controls the discharge flow rate of the hydraulic pump according to the set equal horsepower diagram. Finally, the horsepower control unit controls the discharge flow rate of the hydraulic pump according to the target engine speed set by the dial gauge of the engine and the engine load calculated from the current engine speed.
1, when the operation amount of the operating portion sharply increases, an operation signal is inputted to the working flow control portion so that the flow rate of the hydraulic pump is rapidly increased. As a result, The discharge pressure suddenly increases and the required horsepower of the hydraulic pump rapidly increases. Then, the suddenly increased discharge pressure of the hydraulic pump is input to the equal horsepower regulating unit, and the discharge flow rate of the hydraulic pump starts to decrease.
However, the flow rate of the hydraulic pump is reduced by the constant power regulator after a certain time from the point at which the discharge pressure of the hydraulic pump rises due to the response delay time of the regulated horsepower. In this way, the discharge pressure of the hydraulic pump continuously rises during the time when the equi-horsepower control point is delayed, and the hydraulic shock occurs. As a result of the hydraulic shock, the required horsepower of the hydraulic pump is rapidly increased as in the section A of FIG.
As described above, the sudden increase in required horsepower of the hydraulic pump acts as a large load on the engine, and the rotational speed of the engine suddenly drops below the set target rotational speed. If the engine rotation speed is suddenly lowered in this way, there arises a problem that not only the amount of soot is increased but also the vibration is increased. Particularly, as in the section B of FIG. 1, the engine has a low output increase rate of the engine in a section (turbo charger time lacking period) in which the drive of the turbo charger reaches a steady state, And the vibration becomes larger.
On the other hand, when the rotational speed of the engine suddenly drops from the target rotational speed, the horsepower control unit lowers the driving force of the hydraulic pump from the maximum horsepower (200 mA) to the minimum horsepower (600 mA) As a result, the flow rate of the hydraulic fluid discharged from the hydraulic pump is reduced and the working efficiency of the construction machine is lowered.
Fig. 2 is a rear view showing the outline of the above-mentioned process. Referring to FIG. 2, it can be seen that, due to the time delay at the time of the equi-horsepower control, the discharge pressure of the hydraulic pump suddenly increases like the C-line, and then the flow rate and the pressure are returned to the equi-horsepower line again.
SUMMARY OF THE INVENTION [0005] In summary, the conventional hydraulic pump control apparatus has a hydraulic shock in which the required horsepower of the hydraulic pump is rapidly increased due to the time delay of the equi-horsepower control point by the equi-horsepower control unit, The rotational speed of the engine is rapidly lowered to increase the amount of smoke and vibration. In order to recover the rotational speed of the engine to the target rotational speed, the horsepower of the hydraulic pump is drastically lowered in the process of driving the hydraulic pump with the minimum horsepower The work performance of the construction machine is deteriorated.
The control unit may control the horsepower control unit so that the flow rate of the hydraulic pump is reduced to return the engine rotational speed to the target rotational speed when the engine rotational speed is less than the target rotational speed. . When the rotational speed of the engine becomes larger than the target rotational speed by controlling the discharge flow rate of the hydraulic pump to be small, a control signal is output to the horsepower control unit again to increase the flow rate of the hydraulic pump. As described above, the rotational speed of the engine is manually controlled by the load of the hydraulic pump. When the engine load ratio (load torque of the engine with respect to the engine maximum torque) is increased as shown in Fig. 3, the rotational speed of the engine becomes close to the target rotational speed , The engine rotation speed becomes higher than the target rotation speed as the engine load ratio becomes smaller. Thus, even when the load transmitted from the hydraulic pump to the engine is small, the rotational speed of the engine is maintained at a high level, resulting in a large energy loss.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a power control apparatus for a construction machine capable of improving fuel economy by keeping the rotational speed of the engine constant at a target rotational speed.
It is another object of the present invention to provide a hydraulic pump power control apparatus for a construction machine capable of preventing occurrence of hydraulic shock due to time delay at the time of equi-horsepower control.
It is still another object of the present invention to provide a power control apparatus for a construction machine capable of preventing a sudden decrease in the rotational speed of the engine even when a sudden and large manipulated variable is input from the control unit, thereby improving the work performance of the construction machine.
In order to achieve the above object, a power control apparatus for a construction machine according to the present invention comprises an engine (10) connected to a hydraulic pump (20) to drive the hydraulic pump (20); And an engine load ratio defined by a ratio of a load torque of the engine to an engine maximum torque calculated from the input engine target rotation speed, and wherein the engine rotation speed command value is calculated based on the engine load ratio so that the engine is driven at the target rotation speed, And outputs the calculated value to the engine.
According to an embodiment of the present invention, the
The power control apparatus as described above includes a
When the load pressure Pd sensed by the
The
According to the problem solving means as described above, the engine rotational speed command value according to the engine load ratio is calculated and output to the engine, whereby the engine rotational speed can be maintained at the target rotational speed, thereby improving the fuel economy of the construction machine And vibration can be reduced.
In addition, the equipment control unit, which receives the engine load factor from the engine control unit, calculates the engine rotation speed command value and outputs the calculated engine rotation speed command value to the engine control unit, thereby making it easy to apply the power control system of the present invention to the existing system .
In addition, by gradually changing the required horsepower of the hydraulic pump according to the load pressure, it is possible to prevent the hydraulic shock caused by the time delay of the conventional horsepower control. In addition, by preventing the hydraulic shock, it is possible to prevent the engine rotational speed from being rapidly lowered by the load of the hydraulic pump, thereby minimizing the soot amount and vibration of the engine.
In addition, in order to return the engine rotational speed, there has been a problem that the required horsepower of the hydraulic pump is drastically reduced to lower the workability of the construction machine. However, since the required horsepower of the hydraulic pump is gradually brought closer to the target pump- , It is not necessary to return the rotational speed of the engine, thereby preventing the required horsepower of the hydraulic pump from being reduced, thereby improving the workability of the construction machine.
Particularly, when the load pressure Pd is the no-load pressure Pd1, the target pump-required horsepower is set to the minimum horsepower POmin so that the load applied to the engine by the hydraulic pump can be minimized, thereby improving the fuel economy .
Further, by setting the maximum set pressure Pd2 at which the target pump required horsepower becomes the maximum horsepower POmax to be equal to or smaller than the pressure Pd2 at the start point of equi-horsepower control of the maximum horsepower POmax of the hydraulic pump, The discharge flow rate of the hydraulic pump can be secured as much as possible at the time when the horsepower reaches the target pump required horsepower, thereby further improving the workability.
In addition, by setting the predetermined time (DELTA t) to be proportional to the horsepower difference value (DELTA PO) between the current pump required horsepower of the hydraulic pump and the target horsepower required horsepower, the horsepower difference value And when the horsepower difference value? PO is large, it is possible to secure a sufficient control time that the hydraulic shock does not occur.
On the other hand, by configuring the horsepower control unit as an electron proportional pressure reducing valve for varying the opening amount of the oil path connecting the horsepower control unit, the pilot pump, and the horsepower control unit, the idea of the present invention can be applied to a general hydraulic system in general .
Hereinafter, a power control apparatus for a construction machine according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
Referring to FIG. 4, the power control apparatus for a construction machine according to an embodiment of the present invention includes an
The
The
5, an engine rotation speed command value for an engine load ratio for keeping the rotation speed of the
Accordingly, when the target rotational speed of the engine is input to the
As a result, the fuel injection amount is controlled so that the torque can be increased in accordance with the load factor of the engine, so that the rotational speed of the
Hereinafter, the rotational speed control method of the engine having the above-described configuration will be described in detail.
Referring to Fig. 7, when the engine target rotation speed is first set from the
Then, the
When the engine load ratio is calculated, the
On the other hand, when the engine target rotation speed is input from the
The power control apparatus and the power control method have been described above with reference to the rotational speed control of the engine. The power control apparatus and the power control method based on the control of the
4, the
The
The operation
The equal
The
The present embodiment is defined as a
More specifically, when the
The electromagnetic proportional
The
The
The
9, a pump horsepower increase / decrease rate is set in the
When the load pressure Pd is inputted from the
When the horsepower difference value? PO is calculated, the
When the calculation of the horsepower increase rate is completed, the
8, the target pump-required horsepower is set to the minimum horsepower POmin when the load pressure Pd detected by the
Hereinafter, the power control method using the hydraulic pump control having the above-described configuration will be described in detail.
Referring to Fig. 12, the load pressure Pd detected by the
In this state, as shown in Fig. 12, when the operation amount of the
To this end, the
As described above, the
Conventionally, when the engine rotational speed drops below the target engine rotational speed set from the
Referring to FIG. 13, the process of raising the
FIG. 14A shows the boom rising speed and the engine rotation speed by the conventional hydraulic pump control apparatus, and FIG. 14B shows the change amounts of the boom rising speed and the engine rotation speed by the hydraulic pump control apparatus according to the present embodiment.
Referring to FIG. 14A, the boom rising speed rapidly increases due to an abrupt flow rate and an increase in load pressure. However, due to the hydraulic shock, the engine rotational speed is suddenly lowered as in the case of the E region, and therefore, the horsepower control is started and the required horsepower of the
However, referring to FIG. 14B, in the present embodiment, the increase rate of the boom rising speed is somewhat lower than that in FIG. 14A, but the boom rising speed is not lowered in the section F and the engine rotation speed is not significantly lowered as in the G section . As a result, not only the workability of the construction machine can be improved, but also the occurrence of soot and vibration can be minimized.
On the other hand, when the load pressure does not fluctuate to the reference pressure, the horsepower control of the
FIG. 1 is a graph schematically showing changes in pump discharge flow rate and required horsepower, engine output and rotation speed, and horsepower control current command value according to the existing hydraulic pump control apparatus under the class operation condition of the operation unit,
Fig. 2 is a graph showing the control process of Fig. 1 in the pressure-flow rate diagram (back horsepower diagram) of the hydraulic pump,
3 is a graph schematically showing the engine rotation speed according to the conventional engine load ratio,
4 is a conceptual diagram schematically showing a power control apparatus for a construction machine according to an embodiment of the present invention,
FIG. 5 is a graph schematically showing an engine rotation speed command value according to the engine load ratio set in the equipment control unit of FIG. 4,
Fig. 6 is a graph schematically showing the engine rotation speed according to the engine load ratio of the engine controlled by the power control apparatus shown in Fig. 4,
FIG. 7 is a flowchart schematically showing a power control process by the power control apparatus shown in FIG. 4,
8 is a graph schematically showing the target pump-required horsepower and current command value for the load pressure set in the control unit of FIG. 3,
FIG. 9 is a graph schematically showing a rise time with respect to a horsepower difference value between the target pump required horsepower set in the control unit of FIG. 3 and the current pump required horsepower,
FIG. 10 is a graph schematically showing a horsepower increase rate with respect to a specific horsepower difference value set in the control unit of FIG. 4,
FIG. 11 is a graph schematically illustrating the maximum equal horsepower diagram and the minimum equal horsepower diagram of the hydraulic pump shown in FIG. 4,
12 is a graph schematically showing the pump discharge flow rate and the required horsepower according to the hydraulic pump control apparatus shown in Fig. 4, the engine output and the rotational speed under the operating condition of the operating unit,
13 is a graph showing the control process of FIG. 12 in a pressure-flow rate diagram (back horsepower diagram) of a hydraulic pump,
FIG. 14A is a graph showing the boom rising speed and the engine rotation speed according to the control process of FIG. 1,
FIG. 14B is a graph showing the boom rising speed and the engine rotation speed according to the control process of FIG.
DESCRIPTION OF THE REFERENCE NUMERALS OF THE DRAWINGS
10;
30;
32; Electron proportional
40; A
60; A
62; Equipment control part? PO; Horsepower difference value
Δt; Rise time, preset time POmin; Pump minimum horsepower
POmax; Pump maximum horsepower Pd; Load pressure
Pd1; No-load pressure Pd2; Maximum setting pressure
Claims (5)
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020090130426A KR101630457B1 (en) | 2009-12-24 | 2009-12-24 | Power control apparatus for construction machinery |
| PCT/KR2010/009207 WO2011078578A2 (en) | 2009-12-24 | 2010-12-22 | Power control apparatus and power control method for construction machinery |
| CN201080058965.6A CN102713089B (en) | 2009-12-24 | 2010-12-22 | Power control apparatus for construction machinery |
| BR112012015598A BR112012015598B1 (en) | 2009-12-24 | 2010-12-22 | power control apparatus and power control method for construction machinery |
| US13/518,743 US8720629B2 (en) | 2009-12-24 | 2010-12-22 | Power control apparatus and power control method of construction machine |
| EP10839775.3A EP2518222B1 (en) | 2009-12-24 | 2010-12-22 | Power control apparatus for a construction machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020090130426A KR101630457B1 (en) | 2009-12-24 | 2009-12-24 | Power control apparatus for construction machinery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR20110073711A KR20110073711A (en) | 2011-06-30 |
| KR101630457B1 true KR101630457B1 (en) | 2016-06-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020090130426A KR101630457B1 (en) | 2009-12-24 | 2009-12-24 | Power control apparatus for construction machinery |
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| KR (1) | KR101630457B1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101452823B1 (en) * | 2012-12-21 | 2014-10-22 | 주식회사 포스코 | Anomaly monitoring device for metal pump of galvanizing snout and method thereof |
| WO2015099437A1 (en) * | 2013-12-26 | 2015-07-02 | 두산인프라코어 주식회사 | Hydraulic system of construction machinery and method of controlling hydraulic system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4967557A (en) | 1988-01-27 | 1990-11-06 | Hitachi Construction Machinery Co., Ltd. | Control system for load-sensing hydraulic drive circuit |
| JP2008151001A (en) * | 2006-12-15 | 2008-07-03 | Komatsu Ltd | Engine load control device of working vehicle |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3589710B2 (en) * | 1994-09-28 | 2004-11-17 | 住友建機製造株式会社 | Engine and pump control devices for construction machinery |
| JP3155722B2 (en) * | 1997-03-06 | 2001-04-16 | 住友建機株式会社 | Engine and hydraulic pump control device for construction machinery |
-
2009
- 2009-12-24 KR KR1020090130426A patent/KR101630457B1/en active IP Right Grant
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4967557A (en) | 1988-01-27 | 1990-11-06 | Hitachi Construction Machinery Co., Ltd. | Control system for load-sensing hydraulic drive circuit |
| JP2008151001A (en) * | 2006-12-15 | 2008-07-03 | Komatsu Ltd | Engine load control device of working vehicle |
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|---|---|
| KR20110073711A (en) | 2011-06-30 |
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