| 摘要 |
Provided is a method for controlling a variable displacement pump using a closed center type directional control valve and calculation by a controller. According to the method of the present invention, it is possible to effectively utilize the variable displacement pump without concerns about engine failure. [Solution] A first virtual discharge pressure is determined from an actual discharge flow rate of the variable displacement pump based on a characteristic valve determining a discharge pressure and the discharge flow rate of the variable displacement pump, and a virtual bleed-off flow rate is determined based on a virtual bleed-off area of the closed center type directional control valve, which is determined according to the amount that the directional control valve operates. A second virtual discharge pressure of the variable displacement pump is determined from the virtual discharge flow rate of the variable displacement pump based on a value obtained by calculating an actuator flow rate and the virtual bleed-off flow rate, and the variable displacement pump is controlled based on the smaller value of the first virtual discharge pressure and the second virtual discharge pressure. |
