Patent ID: 7549287

Claim:
A method of operation of a hydrostatic system, comprising steps of: providing a hydrostatic system including a fluid motor driven by a pump powered by an engine, at least one of the motor and the pump having a variable displacement for controlling a speed of operation of the motor, and a controller configured for monitoring the speed of operation of the motor and an operating characteristic of the engine, and automatically controlling the displacement responsive thereto, comprising steps of: continually monitoring the speed of operation of the motor and the operating characteristic of the engine, and: if the operating characteristic is indicative of engine performance above a predetermined first threshold, then controlling the displacement for maintaining the speed of operation of the motor at about a predetermined value, and: if the operating characteristic is indicative of engine performance below the first threshold, then automatically holding the displacement at a constant value equal to a stored most recent displacement value, and if the operating characteristic subsequently increases to be equal to or greater than a second threshold, then automatically controlling the displacement for maintaining the speed of operation of the motor at the predetermined value.