A system and method for controlling a pump/motor

摘要

A system for transmitting power hydraulically to and from the wheels of a motor vehicle includes an accumulator containing fluid at relatively high pressure, a reservoir containing fluid at lower pressure, and a pump/motor driveably connected to the wheels and having a variable volumetric displacement for pumping fluid between the accumulator and the reservoir. A first circuit connects the inlet to the reservoir and the outlet to the accumulator. A second circuit includes a first path having a low flow rate capacity, a second path having a higher flow rate capacity. A controller switches between pumping operation and motoring operation, opens and closes the first path during motoring operation, and reduces the displacement before switching between pumping operation and motoring operation.