Method for actuating a hydraulic servo system
View Patent ↗A method for actuating a hydraulic servo system with a proportional valve that converts an electrical control signal into a hydraulic pilot pressure with which the hydraulic servo system is actuated. An additional impulse is fed to the proportional valve at the beginning of a desired change of the electrical control signal.
1. A method for actuating a hydraulic servo system with the aid of a proportional valve that converts an electrical control signal into a hydraulic pilot pressure with which the hydraulic servo system is actuated, said method comprising the steps of: providing a first electrical control signal to the proportional valve, and feeding an additional electrical control signal impulse to the proportional valve before a beginning of a desired change of the first electrical control signal in order to reduce a time delay between a desired hydraulic pilot pressure increase and an actual hydraulic pilot pressure increase.
2. A method in accordance with claim 1 , including the step of feeding the additional electrical control signal impulse as a current impulse, and adjusting a level and duration of the current impulse as a function of a system temperature.
3. A method in accordance with claim 1 , wherein the additional electrical control signal impulse is a square-wave impulse.
4. A method in accordance with claim 1 , including the steps of: measuring an actual pressure in the hydraulic servo system when the proportional valve is actuated, and comparing the measured actual hydraulic pressure with a desired hydraulic pressure.
5. A method in accordance with claim 4 , including the step of feeding the additional electrical control signal impulse to the proportional valve before a desired change of the first electrical control signal when a deviation of the actual hydraulic pressure in the hydraulic servo system from the desired hydraulic pressure exceeds a predetermined value.
6. A method in accordance with claim 1 , including the step of measuring an actual pressure in, the hydraulic servo system when the proportional valve is actuated both with and without an additional impulse.
7. A method in accordance with claim 6 , including the step of comparing the measured actual pressure values with each other both with and without an additional impulse.
8. A method in accordance with claim 7 , including the step of feeding the additional electrical control signal impulse to the proportional valve before a desired change of the first electrical control signal when deviations of the measured actual hydraulic pressure values from corresponding desired hydraulic values exceed predetermined deviation values.
9. A method in accordance with claim 1 , wherein the first electrical control signal provided to the proportional valve is a ramp signal.
10. A method in accordance with claim 1 , wherein the hydraulic servo system includes at least one of a clutch and a variable speed drive unit of a belt-driven conical-pulley transmission having a variably adjustable transmission ratio.