KR19980022863A - Engine-pump control method of construction machinery - Google Patents

Abstract

The present invention relates to a method for controlling an engine-pump of a construction machine, and more particularly, to an engine, a pump driven by an engine, a suction torque adjusting valve capable of adjusting suction torque of a pump, and a suction torque adjusting valve. And a controller for controlling the suction torque of the pump by inputting the suction torque adjustment current, an engine speed detector for detecting the engine speed, and a throttle servomotor for adjusting the output of the engine by adjusting the throttle angle of the engine. In the engine-pump control method of construction machinery, the input current of the suction torque control valve is checked to determine whether a problem occurs, and in case of a problem, the engine speed is lowered to protect the pump and the driver is aware of the problem. In addition, by providing an engine-pump control method of construction machinery that normally operates the engine when it is normal, the pump operates stably. It can be, there is an effect that can prevent the risk of overloading the pump beforehand.

Description

Engine-pump control method of construction machinery

The present invention relates to a method for controlling an engine-pump of a construction machine to prevent the pump from being damaged by lowering the engine driving speed when the suction torque adjusting valve is not normally operated in the construction machine.

In general, the engine-pump control system of a construction machine includes an engine 10, a pump 11 driven by the engine 10, and a suction torque of the pump as shown in FIG. An adjustable suction torque adjustment valve 12, a controller 13 for controlling the suction torque of the pump 11 by inputting a suction torque adjustment current to the suction torque adjustment valve 12, and the engine 10 Engine speed detector (14) capable of detecting the speed of () and a throttle servomotor (15) for adjusting the output of the engine (10) by adjusting the throttle angle of the engine (10).

Looking at the operation of the engine-pump control system of the construction machine configured as described above, the mechanical energy generated from the engine 10 which is a power source for supplying energy is converted into fluid energy by the pump 11, and then flow rate not shown It is supplied to hydraulic actuators, such as hydraulic cylinders and hydraulic motors, that drive the work equipment through control valves.

At this time, the method for adjusting the suction torque of the pump 11 with respect to the output torque of the engine 10 is the suction torque adjustment for adjusting the maximum suction torque that the pump 11 can inhale in the controller 13 A current is output, and this suction torque adjustment current is used as a control input of the suction torque adjusting valve 12, so that the speed of the engine 10 detected from the engine speed detector 14 is rated as a reference input corresponding to the rated suction torque. Controlled through the controller 13 to be equal to the engine speed. That is, if the controlled speed of the engine 10 is the rated speed, it is assumed that the pump 11 completely absorbs the rated output torque of the engine 10, and the actual driving speed of the engine 10 is rated suction. In order to have a value equal to the rated speed corresponding to the torque, the pump 11 is controlled using a suction torque adjustment current.

Referring to the engine output torque diagram 20 and the pump suction torque diagrams 21 and 22 shown in FIG. 2, the engine output torque is shaped like the diagram 20 by the characteristics of the engine 10. The suction torque of the pump 11 when the suction torque adjusting valve 12 operates normally is the same as that of the diagram 21.

At this time, when the engine output torque is larger than the pump suction torque when the engine output torque diagram 20 and the pump suction torque diagram 21 are on the left side, the engine output torque is larger than the pump suction torque. The speed of (10) is increased to move to the right toward the contact point (a). When the pump suction torque is greater than the engine output torque when the pump suction torque is greater than the engine output torque when the right side of the contact point (a), The speed of the engine 10 slows down and moves to the left toward the contact a so that the equipment is ideally operated at the contact a where the engine output torque and the pump suction torque coincide.

However, the output of the suction torque adjustment valve 12 which forms an output pressure for adjusting the swash plate angle of the pump 11 because the input current for controlling the suction torque adjustment valve 12 from the controller 13 is not normally applied. When it does not act on this pump 11, the suction torque of the pump 11 becomes large, and the pump suction torque becomes like the curve 22, and accordingly, the engine output torque curve 20 and the pump suction torque curve 22 The contact is moved from contact a to contact b.

Referring to the diagram 23 representing the maximum rated suction torque allowed for the pump 11, the pump suction torque at the contact point b at which the equipment is operated is greater than the maximum rated suction torque of the pump 11. There is a problem that it is impossible to stably operate the pump 11 and cause a shortening of the life of the pump 11.

Accordingly, the present invention is to solve the above problems, an object of the present invention, a problem occurs in the control signal between the controller for outputting the suction torque adjustment current and the suction torque adjustment valve, the output of the suction torque adjustment valve In an abnormal case, it provides an engine-pump control method for a construction machine that can stably operate the pump by controlling the output of the engine and prevent the risk of overloading the pump in advance.

1 is a configuration diagram of an engine-pump control system of a general construction machine,

2 is an engine output torque diagram and a pump suction torque diagram according to FIG. 1;

3 is an operation flowchart of a controller for performing an engine-pump control method for a construction machine according to the present invention.

* Explanation of symbols used in the main part of the drawing

10: engine

11: pump

12: suction torque adjustment valve

13: controller

14 engine speed detector

15: Throttle Servo Motor

20: Engine output torque diagram

21: Pump suction torque diagram in normal operation of suction torque adjustment valve

22: Pump suction torque diagram when suction torque adjusting valve is abnormal

23: Maximum rated suction torque diagram of pump

a, b, c: engine-pump drive point

Features of the present invention for achieving the above object, the engine, a pump driven by the engine, a suction torque adjustment valve that can adjust the suction torque of the pump, and suction torque adjustment to the suction torque adjustment valve Construction comprising a controller for controlling the suction torque of the pump by inputting a current, an engine speed detector for detecting the engine speed, and a throttle servomotor for adjusting the output of the engine by adjusting the throttle angle of the engine. In the engine-pump control method of a machine, an engine-pump control method of a construction machine which protects a pump by lowering the driving speed of an engine in case of abnormality by checking a suction torque adjustment current input from a controller to a suction torque adjustment valve. have.

Hereinafter, a preferred embodiment of the engine-pump control method for a construction machine according to the present invention will be described in detail with reference to the accompanying drawings.

In describing FIG. 3, it will be apparent that the above-described FIGS. 1 and 2 are referred to in the same manner as the related art.

First, as shown in FIG. 2, when the input current for controlling the suction torque adjusting valve 12 from the controller 13 is not normally applied, the pump suction torque diagram 22 is again examined. At the time point b, the suction torque of the pump 11 was greater than the maximum rated suction torque allowed by the pump 11, which impeded the operation of the pump 11. At this time, if the driving speed of the engine 10 is lowered not to exceed the maximum rated suction torque of the pump, the equipment cannot be operated normally at the state point (c) where the engine-pump is driven, but the pump does not exceed the maximum rated suction torque of the pump. Can protect.

3 is an operation flowchart of the controller 13 for performing the engine-pump control method of the construction machine according to the present invention.

The operation of the controller 13 largely checks the input current of the suction torque adjusting valve 12 to determine whether the suction torque adjusting current output from the controller 13 is normally applied to the suction torque adjusting valve 12. (S1) and, if it is determined that the suction torque adjustment current is not normally applied from the controller 13 to the suction torque adjustment valve 12 in the first process, to inform the driver of a problem, to protect the pump 11 In the second process (S10) of controlling the driving speed of the engine 10 and the first process, when it is determined that the suction torque adjustment current is normally applied from the controller 13 to the suction torque adjustment valve 12, the engine 10 can be divided into a third process (S20) for normal operation.

Looking at the operation of the controller 13 in detail as follows.

First, the controller 13 determines whether an input current for adjusting suction torque is normally applied to the suction torque adjusting valve 12 (S1). If it is determined in step S1 that the input current of the suction torque adjusting valve 12 is abnormal, the controller 13 lights a warning light to inform the driver that a problem has occurred (S2), and the engine 10. The speed of the engine 10 is detected by adjusting the throttle angle by detecting the speed of the throttle servomotor 15 (S3). That is, by controlling the output of the engine 10 in the same manner as in step S3, the suction torque of the pump 11 at the engine-pump driving state point is controlled not to be greater than the maximum rated suction torque of the pump 11. It is. Therefore, even when the suction torque adjusting valve 12 cannot normally adjust the suction torque of the pump 11, the suction torque of the pump 11 during the engine-pump operation is smaller than the allowable maximum rated suction torque of the pump 11 so that the pump (11) can be operated stably. In addition, when it is determined in step S1 that the input current of the suction torque adjusting valve 12 is not abnormal, the suction torque adjusting valve 12 is regarded as normally adjusting the suction torque of the pump 11, When the warning light is turned on, the warning light is turned off (S4), and the controller 13 reduces the output of the engine 10 to a normal state (S5).

Thereafter, the process returns to the above-described step (S1) to repeat the above series of processes.

As described above, according to the engine-pump control method of a construction machine according to the present invention, the controller checks whether there is a problem in connection between the controller and the suction torque adjustment valve, and controls the output of the engine when the problem is detected to control the engine driving speed. By adjusting, it is possible to prevent the pump from being damaged and shorten the life of the pump, and to stably operate the pump.

Claims (3)

An engine, a pump driven by the engine, a suction torque adjustment valve for adjusting the suction torque of the pump, and a controller for controlling the suction torque of the pump by inputting a suction torque adjustment current to the suction torque adjustment valve. And an engine speed detector capable of detecting an engine speed, and a throttle servomotor for adjusting the output of the engine by adjusting the throttle angle of the engine. Check the input current of the suction torque control valve to determine whether there is a problem, and if a problem occurs, reduce the engine's driving speed to protect the pump and recognize the problem to the driver. Engine-pump control method. The method according to claim 1, And the controller controls the throttle angle to lower the driving speed of the engine when the input current of the suction torque adjusting valve is generated, thereby controlling the throttle angle. The method according to claim 1 or 2, wherein the controller, A first process of checking the input current of the suction torque adjusting valve to determine whether the suction torque adjusting current output from the controller is normally applied to the suction torque adjusting valve; A second process of notifying the driver of a problem and controlling the driving speed of the engine to protect the pump if it is determined that the suction torque adjusting current is not normally applied from the controller to the suction torque adjusting valve in the first step; And if it is determined that the suction torque adjusting current is normally applied from the controller to the suction torque adjusting valve in the first process, performing a third process of operating the engine normally.