Torque limiting control system for a hydraulic work machine

An apparatus for controlling an electrohydraulic system of a work machine having an engine that drives a variable displacement pump, comprising:

• a pump displacement setting device adapted to produce a pump command signal indicative of a desired displacement of the variable displacement pump;
• a pressure sensor adapted to detect the fluid pressure associated with the variable displacement pump and produce a pressure signal indicative of the detected fluid pressure;
• an engine speed sensor adapted to detect the speed of the engine and produce an actual engine speed signal indicative of the detected engine speed;
• torque computing means for receiving the pump command and pressure signals, responsively computing the torque demand on the engine and producing a torque demand signal;
• torque limiting means for receiving the torque demand and engine speed signals, responsively determining a torque limit associated with the engine and producing a torque limit signal;
• and
• scaling means for receiving the pump command and torque limit signals, determining a scaling factor, and modifying the pump command signal in response to the scaling factor to govern the engine torque.