Abstract:Due to its impact structure and easily to drive multi-actuators with a single power source, valve-controlled cylinder is widely used in industrial equipment and mobile machine. Oftentimes, its utilization is limited by its inferior efficiency caused by throttling loss. The most direct method is adopting the direct pump control technology which eliminates the throttle losses. However, to a traditional symmetric pump controlled asymmetric cylinder, a complex compensation circuit is

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... to compensate asymmetric volume flow of the cylinder. And also, the operation stability of the system will become worse when the load force direction changes frequently and the control chamber changes alternatively. A new displacement controlled system that can match the differential area of an asymmetric cylinder based on a new designed asymmetric pump is put forward. To research the working performance and energy efficiency of the designed system, it is used to control the arm cylinder of excavator which works under four quadrants. To verify the feasibility of the new circuit, based on the pre-simulation results, the operating characteristics and energy efficiency characteristics of the arm with the new scheme are studied on a real excavator. The results show that the stability is satisfied, and there is no obviously velocity fluctuation. Compared with the independent metering circuit with pump and valve accordance control, the energy-saving reaches to 57.0% during a working cycle. Key words:asymmetric pump;four-quadrant operating;pump-controlled cylinder;energy efficiency