Impact of Calorific Intensity on the Efficiency of an Internal Combustion Engine Operating Cycle

Abstract

The processes of heat exchange in an internal combustion engine serve as indicators of its good technical condition and efficient operation. The processes of heat exchange and the calorific intensity of engine parts affect the engine reliability and operating life as well as its operating cycle efficiency. The mean effective and mean indicated cycle pressure are the universal criteria of calorific intensity, as a load increase results in an increase in the temperature of the cylinder-piston group. The engine indicator diagram is the most common and efficient way to obtain the required and reliable information on the operating cycle—the process of air-fuel mixture combustion. A thermodynamic analysis of the diagram will allow obtaining more detailed information, which promotes more accurate conclusions with respect to the operating cycle and the technical condition of the engine and its parts. To this end, a simplified method for calculating the amount of heat released during fuel combustion is considered. The method involves presenting the heat release as a sum of heat transferred to gas and heat transferred to the walls of the combustion chamber. This paper provides calculations of heat for each of these processes. Several models for calculating the heat transfer coefficient are presented, and possible errors and inaccuracies of the result obtained using the suggested method are outlined.