Pressure control of rotary accumulator

Accumulator is widely used in hydraulic system for the advantage of high power density. However, the energy density of accumulator is low and the system pressure is coupled with energy quantity stored. Rotary Accumulator (RA) exploits the potential of every part of accumulator, improves the energy density through rotation of the shell and internal fluid and makes the system pressure controllable by confining the nadir of the paraboloidal pressure distribution. Based on the possible operation conditions and the energy storage mechanism, the paper analyzes all the working modes of RA and proposes a pressure stabilizing control strategy for RA system with a constant displacement pump/motor. Finally, the strategy is simulated on a parallel hydraulic hybrid vehicle and the results illustrate that RA has good pressure regulating capability with this strategy, which provides reference for design and control of the emerging component RA.