Thermodynamic analysis of endoreversible six-stroke Otto cycle with respect to equivalence ratio, residual gas fraction and mean piston speed

Abstract

The analysis of the six-stroke Otto cycle was performed using the finitetimethermodynamics dependence on mean piston speed, equivalence ratioand residual gas fraction. In the analysis, friction loss, internalirreversibilities, heat transfer losses were taken into account by empiricalcorrelations. Relations between power output, thermal efficiency, andcompression ratio were obtained by detailed numerical examples. Theresults were presented as comparative for four- and six-stroke Otto cycle. Itwas assumed that the cycles operate with the same mixture flow per secondso that both performances of cycles can be compared. The study showedthat more fuel flow can be supplied to the six-stroke Otto cycle for the samemixture flow. However, there was a slight increase in the maximum cycletemperature. For this reason, the results are crucial in providing a goodguideline for evaluating and improving the performance of real six-strokeOtto engines.