Abstract: A method of controlling an electro-hydraulic system having an engine driving a variable displacement pump, a hydraulic valve and a hydraulic actuator in order to achieve more efficient engine operation is disclosed. The pressures in the electro-hydraulic system are monitored and commands are received indicating the desired movement of the hydraulic actuator. Based on the pressure and the commands, the operation being performed by the machine is determined and the engine is set to an efficient setting for the particular segment of machine operation.

Abstract: A control valve in fluid communication with an actuator may include a pressurized pilot supply and a fluid reservoir fluidly connected to a passageway defined by a valve body. A pilot operator is selectively moveable within the passageway, and a flow metering operator is moveably disposed within the passageway. A fluid make-up operator, disposed in the passageway and in fluid communication with the fluid reservoir and the actuator, directs pressurized pilot supply fluid in response to a decrease in actuator pressure coinciding with a cavitation condition within the actuator. A control chamber within the valve body contains pressurized fluid from the pilot supply and is in fluid communication with the flow metering operator. The flow metering operator fluidly connects the actuator with the fluid reservoir under the influence of the pressurized fluid within the control chamber through activation by either the pilot operator or the fluid make-up operator.