Influence of the compression ratio variation method on the average cycle pressure

Abstract

Introduction (problem statement and relevance). When equipping a spark ignition engine with supercharging, there is a need to reduce compression ratio ε. Generally, it can be achieved by means of four different methods. Therefore, it is important to know the nature of influence of each method for ε variation on the value of average cycle pressure pt .The purpose of the study is to analyze the nature and degree of influence of the compression ratio for different methods of its variation on average pressure value pt of the Otto thermodynamic cycle. The conclusions made based on this analysis can be extrapolated to real objects in case of necessity of engine design changing.Methodology and research methods. In order to solve the assigned task, a computational experiment has been conducted.Scientific novelty and results. The calculation results have led to the conclusion about different and, in one of the considered cases, very significant influence of the method for varying of ε on the Otto cycle average pressure and on the nature of functional relationship pt = f (ε). Practical significance. The analysis results can be used in order to improve and design reciprocating internal combustion engines with spark ignition.