Computational Modeling of Internal Combustion Engines: Influence of Compression Ratio in the Indicated Performance Curves

This paper describes the development of a computational simulation model for internal combustion engines, with spark ignition, powered by ethanol fuel which include the combustion with finite duration, the instantaneous heat transfer and the intake and exhaust processes. The simulation model calculates the thermodynamic properties of each element involved in the process at every discretized instant of the motor cycle using as input the data related to the engine and to its desired operating regime.

The simulation model has as a result the temperature and the instantaneous pressure profiles inside of the combustion chamber as a function of the crankshaft angle in the range of one cycle. Besides that, the algorithm includes a variation range of certain parameters of the engine project to evaluate the influence of each one of these parameters in its performance. One of these important parameters that can be varied by this algorithm is the compression ratio, whose study of its influence on engine performance curves is discussed in this paper.