(1-15) Numerical Analysis of Auto Ignition and Combustion of n-Butane and Air Mixture in The Homogeneous Charge Compression Ignition Engine by Using Elementary Reactions((NCS-1)Novel Combustion Systems 1-Homogeneous Charge, Premixed Charge Compression Ignition Engines)

Abstract

The present study focuses on clarifying the combustion mechanism of the homogeneous charge compression ignition (HCCI) engine in order to control ignition and combustion as well as to reduce HC and CO emissions by calculating the chemical kinetics of elementary reactions. For the calculations and experiments, n-Butane was selected as fuel since it is the fuel with the smallest carbon number in the alkane family that shows two-stage auto-ignition (heat release by low temperature reaction (LTR) and by high temperature reaction (HTR)) similar to higher hydrocarbons such as gasoline. The CHEMKIN code was used for the calculations assuming zero dimensions in the combustion chamber and adiabatic change. Calculations were carried out for various parameters, including : equivalence ratio, initial temperature, initial pressure, compression ratio, engine speed and initial chemical species concentrations. The influences of these parameters on the appearance timing of LTR and HTR, and on the combustion duration of LTR and HTR were clarified. The results of the present study indicate that in order to reduce HC and CO emissions in exhaust gas and/or to maintain high combustion efficiency for the HCCI engine, it is necessary that the maximum temperature of the combustion cycle be over 1500K.