Theoretical and experimental research on the port timing of a compressed air engine

This study presents a theoretical model and an experimental investigation of a piston engine driven by compressed air. The compressed air engine (CAE) is proposed which is modified from a conventional internal combustion engine. The experiments in this study have used a test bench to examine the output torque and power performance and pressure variations of CAE at different port timing. The study has found that port timing has a direct influence on the working performances of CAE. Based on the theoretical analysis, the model of CAE developed for engine performance analysis and working process is described in this paper. In addition, good agreement of simulation results is obtained between the model and the test. The results show that, as intake advance angle increases, the cylinder pressure decreases during the expansion stroke stage and the exhaust stroke stage. An increase of cylinder pressure is shown at larger intake sustain angle. Moreover, one can find that compared with exhaust advance angle, the intake advance angle and the intake sustain angle have more influence on output torque and power. Consequently, this study of this paper will provide a theoretical and an experimental basis for further study on optimizing the design of CAE.