Optimal Accumulator Sizing for Mobile Applications

For traditional applications, accumulator sizing is a relatively straightforward task as space limitations do not usually impose a significant design constraint. For mobile applications, and in particular, hydraulic hybrid systems, space limitations typically pose the most significant constraint on accumulator design.

The two key constraints placed on an accumulator system for a mobile application are its size and maximum operating pressure. This leaves the designer free to specify the minimum system operating pressure and the accumulator precharge pressure. The former is chosen based on required system performance - below some pressure, system performance becomes unacceptable. This paper presents results from a thermohydraulic study whose results show that for optimal performance, the precharge pressure should be as high as possible in piston accumulators.