ANALYSIS OF HOMOGENEOUS CHARGE COMPRESSION IGNITION ENGINE WITH EMPHASIS ON COMBUSTION TIMING AND REACTION RATE

Abstract

ANALYSIS OF HOMOGENEOUS CHARGE COMPRESSION IGNITION ENGINE WITH EMPHASIS ON COMBUSTION TIMING AND REACTION RATE Arunim Bhattacharya, MS Department of Mechanical Engineering Northern Illinois University, 2017 Dr. Pradip Majumdar, Director HCCI engines are a class of engines which use high compression ratio to ignite a charge of air-fuel mixture, essentially eliminating the need for spark plugs. This contrasts with diesel engines (although HCCI can be used for diesel engines) where the fuel is injected near the top dead center of the compression stroke regime. Gasoline HCCI engine is of significance because it attempts to improve the characteristics of the engine, for example the thermal efficiency. High compression ratio comes with higher thermal efficiency, yet the peak temperature remains low enough to have low production rates of harmful oxides of nitrogen and formation of soot. However, there are certain challenges associated with such type of engine, one of which and perhaps the most important of all is how to control the combustion rate. Flow dynamics and chemical-kinetics analysis, are essential to predict combustion timing, duration, and rate. The objective of this study is to analyze a HCCI engine using simulation analysis models including a three-dimensional CFD simulation model. Simulation analysis is carried out using a generic HCCI engine, initially with simplified chemical kinetics and using detailed chemical kinetics and RANS turbulence CFD model. A sensitivity analysis of the effect of rpm on the combustion time, burn duration, heat release, efficiency and emission concentration is carried out. NORTHERN ILLINOIS UNIVERSITY