Performance analysis of an irreversible Miller cycle with considerations of relative air-fuel ratio and stroke length

The performance of an air standard Miller cycle is analyzed using finite-time thermodynamics. The results show that if compression ratio exceeds certain value, the power output first increases and then starts to decrease with increasing relative air-fuel ratio, while if compression ratio exceeds certain value, the power output decreases with increasing relative air-fuel ratio. The results also show that if compression ratio is less than certain value, the power output decreases 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 increase in compression ratio, the increase of stroke length results in decreasing the power output. The results obtained from this work can be helpful in the design and evaluation of practical Miller engines. (C) 2011 Elsevier Inc. All rights reserved.