Mobile pieces of machinery (e.g., excavators) often include hydraulic systems having hydraulically powered linear and rotary actuators used to power various active machine components (e.g., linkages, tracks, rotating joints, etc.). Typically, the linear actuators include hydraulic cylinders and the rotary actuators include hydraulic motors. By accessing a user interface of a machine control system, a machine operator can control movement of the various machine components.
A typical piece of mobile machinery includes a prime mover (e.g., a diesel engine, spark ignition engine, electric motor, etc.) that functions as an overall source of power for the piece of mobile machinery. Commonly, the prime mover powers one or more hydraulic pumps that provide pressurized hydraulic fluid for driving the active machine components of the piece of machinery. The prime mover is typically required to be sized to satisfy a peak power requirement of the system. Because the prime mover is designed to satisfy peak power requirements, the prime mover often does not operate at peak efficiency under average working loads.
The operation of the active hydraulic components of the type described above can be characterized by frequent accelerations and decelerations (e.g., overrunning hydraulic loads). Due to throttling, there is often substantial energy loss associated with decelerations. There is a need for improved systems for recovering energy losses associated with such decelerations.
USPTO Backgrounds
USPTO Backgrounds