Performance analysis of irreversible Atkinson cycle with considerations of stroke length and volumetric efficiency

Abstract

This paper presents finite time thermodynamics analysis of an irreversible air standard Atkinson cycle. An irreversible Atkinson cycle model, which is closer to practice, is established. In this model, the effects of stroke length and volume efficiency by considering the non‐linear relation between the specific heats of working fluid and its temperature, the frictional loss, the internal irreversibility and heat transfer loss are analysed. The results show that if compression ratio is less than certain value, the power output increases with increasing stroke length, while if compression ratio exceeds certain value, the power output first increases and then starts to decrease with increasing stroke length. With further increasing compression ratio, the increase in stroke length results in a decrease in the power output. The results also show that, throughout the compression ratio range, the power output increases with increasing volumetric efficiency. The results obtained in the present study are of importance to provide good guidance for performance evaluation and improvement of practical internal combustion engines.