Prediction of Two-Cycle Engine Performance Characteristics

Previous papers published by the author have described unsteady gas flow through a naturally aspirated two-cycle engine and the most recent of these publications details a theoretical modelling of the gas exchange or scavenge process for the cylinder of this type of power unit. This results in the ability to predict the trapped charge state, mass, and purity characteristics. With such information it becomes sensible to apply a closed cycle thermodynamic analysis to it and to further predict directly power, torque, and fuel consumption characteristics. This paper describes such a simple closed cycle analysis and compares the theoretical results of power, mean effective pressure, specific fuel consumption, and cylinder pressure diagrams with corresponding measured data from two engines.