Анализ расчетов идеального и реального циклов двигателя внутреннего сгорания

Abstract

The purpose of this article is to study the thermodynamic efficiency of the real cycle of the internal combustion engine. There are various methods for calculating the values of the main thermodynamic parameters of the efficiency factor and average pressure in the nodal points. According to the known data, these results significantly differ from the real ones. The most rational assessment of engine performance is the one using the proven methods. Today there are enough assessment methods of internal combustion engine efficiency, the main ones are entropy and exergy methods. The object of research is the exergy method since it is more versatile. Consideration is given to a 4-stroke diesel engine V-84, which is widely used in military equipment. The ideal and real cycles of the internal combustion engine are calculated. Their input parameters are taken from tactical and technical characteristics of the engine V-84. The exergy method applied to estimate the efficiency of both cycles serves the basis for building entropy vs enthalpy graphs. The latter demonstrate that the maximum losses occur in the real cycle. The conducted calculations allowed to obtain the dependences of the object exergy (object efficiency) on the level of energy dissipation, enthalpy. A graph of exergy variations at cycle control points is obtained. It is proposed to carry on further studies where to assess the reduction of the object performance when in operation. This can be used in the development of the actual technical condition-based operation strategy. The study results are proposed to be used in the comparison of experimental data with reference ones. Moreover, it is possible to predict the changes in the performance level by a generalized criterion, which is the exergy of the working medium.