Patent attributes
A speed control system for a hydrostatic transmission includes an engine having a drive shaft connected to a hydraulic pump. At least one hydrostatic motor is connected to the pump in a closed circuit by a flow line. Connected to the motor via a system shaft is a vehicle system. A controller is connected to a plurality of sensors and a high pressure relief valve that is connected to the flow line between the pump and the motor. Based on information received from the sensors, the controller sets the pump and motor displacements to limit the pressure to a value that will not overspeed the engine and allow the system to automatically provide braking beyond the engine's capability. This may be accomplished through the use of various algorithms.
