Hydraulic hybrid circuit with energy storage for excavators or other heavy equipment

摘要

A hydraulic system powered by a shaft of an engine to control a plurality of hydraulic cylinders including at least one boom lift hydraulic cylinder coupled to a boom to pivot the boom about a horizontal axis, wherein a first variable displacement pump/motor and a second variable displacement pump/motor can be connected to provide a higher flow to the at least one boom lift hydraulic cylinder than a flow achieved by one of the first variable displacement pump/motor or the second variable displacement pump/motor, and a high-pressure accumulator and the first variable displacement pump/motor and the second variable displacement pump/motor can add power back to the engine shaft.

主权项

1. A work machine, comprising:
a chassis; an engine carried by the chassis; a boom pivotally coupled to the chassis and operated by at least one boom swing hydraulic motor coupled to the boom to pivot the boom about a vertical axis; a dipper pivotally coupled to the boom; an implement pivotally coupled to the dipper; and a hydraulic system powered by a shaft of the engine to control a plurality of hydraulic cylinders including at least one boom lift hydraulic cylinder coupled to the boom to pivot the boom about a horizontal axis, a dipper hydraulic cylinder coupled to the dipper to pivot the dipper about a horizontal axis, and an implement hydraulic cylinder coupled to the implement to pivot the implement about a horizontal axis, the hydraulic system comprising:
a first variable displacement pump/motor delivering a fluid either through a first load-holding valve to a head side of the at least one boom lift hydraulic cylinder or through a second load-holding valve to a rod side of the at least one boom lift hydraulic cylinder;a second variable displacement pump/motor delivering a fluid either through a bi-directional valve to a high-pressure accumulator or through both a third load-holding valve and the first load-holding valve to the head side of the at least one boom lift hydraulic cylinder; anda charge pump delivering a fluid to a low-pressure accumulator, a boom hydraulic circuit, and a swing hydraulic circuit;wherein the first variable displacement pump/motor and the second variable displacement pump/motor can be connected to provide a higher flow to the at least one boom lift hydraulic cylinder than a flow achieved by one of the first variable displacement pump/motor or the second variable displacement pump/motor, and the high-pressure accumulator and the first variable displacement pump/motor and the second variable displacement pump/motor can add power back to the engine shaft.