Thermal Analysis of an SI Engine Piston Using Different Thermal Model

In this study, the SI engine piston heat transfer is calculated applying three different models for the heat transfer modeling. In the first model, three approximate and constant temperatures are selected for piston, cylinder and cylinder head and determined the in-cylinder gas temperature, pressure and convection coefficients using two-zone combustion model. In the second model for each of the walls (piston, cylinder and cylinder head), the relevant heat transfer equations with two zone model solved considering three unknown temperature. In third model that is the most accurate method, 24 heat transfer equations coupled with the two zone model were solved simultaneously based on resistor-capacitor thermal network model. Eventually, the three model results compared to study their effect on the piston thermal behavior. It has been shown that using of resistor-capacitor model with less number of equations and consequently less time solution is an appropriate method for solving problems of engine heat transfer. The simulations were done by a MATLAB code and the results have been validated with the experimental data of the EF7.TC engine.