Prediction of Equilibrium Combustion Products of Injecting Additive Urea in Diesel Engine Combustion Chamber

Abstract

Diesel engines are still the prominent source of pollutant emissions globally, despite efforts to shift to electric motors. In 2020, 28% of vehicles produced utilized diesel engines. However, the automotive industry worldwide is actively pursuing methods to curtail exhaust emissions. Three primary strategies have emerged: optimizing combustion processes, refining after-treatment procedures, and exploring alternative fuels and additives. This thesis focuses on the latter strategy - additives and alternative fuels - with the goal of identifying an additive that is capable of mitigating exhaust pollutants. While electric motors and after-treatment processes like urea solutions show promise, this study delves into the potential of urea solution as a diesel additive. Leveraging theoretical mathematical modeling through chemical atom balancing and equilibrium, emissions predictions are made using various concentrations of urea solution in diesel fuel. The Matlab software is employed to solve the system. Through the model, two scenarios are compared: pure diesel and an 80% diesel with 20% urea solution blend, accounting for factors such as pressure, temperature, and equivalence ratio in the combustion chamber. The findings reveal that introducing urea leads to decreased harmful exhaust emissions. Specifically, CO concentration drops by 0.08% to 0.8%, CO2 concentration decreases within lean mixtures by 0.144% to 0.32%, NO concentration reduces by approximately 0.11% to 0.243%, and NO2 concentration diminishes from 0.18% to 0.387%. Additionally, the lower heating value experiences a 3.67% decrease compared to pure diesel.