Impact of Combustion Conditions on the Performance and Emissions of Internal Combustion Engines

Abstract

This final-year project focuses on a combined experimental and numerical study of the impact of combustion conditions on the performance and emissions of internal combustion engines, particularly gasoline and diesel engines. The main objective is to better understand the mechanisms influencing thermal efficiency and pollutant formation, in a context where energy efficiency and emission reduction have become major challenges. The experimental part is based on tests carried out on an engine test bench, enabling the measurement of key parameters such as torque, effective power, specific fuel consumption, air/fuel ratio, and exhaust gas temperature. These measurements allow for a detailed comparison between diesel and gasoline engines, highlighting the effect of operating conditions on overall performance. In parallel, an in-depth numerical study was conducted using two complementary approaches. A first thermodynamic approach, based on chemical equilibrium (Gibbs law), enables the calculation of adiabatic flame temperatures and the molar fractions of species resulting from the complete and dissociated combustion of hydrocarbons (kerosene, methane, diesel). The model incorporates thermodynamic functions (enthalpy, entropy, specific heat) calculated using Bonni McBride coefficients, and the equilibrium equations were solved using the Newton-Raphson method in Fortran.