Analysis of compressed air braking process under variable inlet pressure
WEI Wei, HUANG Rui, CHEN Jun xuan, DOU Wen bo, YU Xiao li
(Power Machinery and Vehicular Engineering Institute, Zhejiang University, Hangzhou 310027, China)


Abstract: Aiming at the problem that the energy recovery effect of hybrid pneumatic engine based on single stage energy storage system decreased with the increase of the pressure of the air tank, double stage energy storage system was used into hybrid pneumatic engine, the viewpoint that the COP (coefficient of performance) could be improved by changing the inlet pressure was drawn preliminary. Based on the theory of variable mass thermodynamics, a mathematical model of compressed air circulation which was verified by testbed was established. Through the steady state simulation of the model, the influence of inlet pressure and air tank pressure on compressing braking process were obtained. The results indicate that the change of inlet pressure and the air tank pressure affect the quality of the recycled compressed air per circulation linearly. the ratio of air tank pressure and inlet pressure is a key factor affecting the COP which will decrease when the ratio increases.
Key words: braking energy recovery; double stage energy storage; inlet pressure