HCCI ENGINE MODELING AND EXPERIMENTAL INVESTIGATIONS—PART 1: THE REDUCTION, COMPOSITION AND VALIDATION OF A n-HEPTANE/ISO-OCTANE MECHANISM

Abstract

A certain possible approach for the control of HCCI chemistry is to use kinetic chemistry mechanisms. This opens a field of interest that lead to the composition of a validated reduced PRF chemistry mechanism. For this purpose a skeletal chemical reaction mechanism for n-heptane and for iso-octane are constructed from a detailed n-heptane and iso-octane mechanism of the Chalmers University of Technology. Subsequently these two mechanisms are forged into one reduced chemical reaction mechanism for mixtures of n-heptane and iso-octane (39 species and 47 reactions). This mechanism is numerically validated against the Chalmers mechanisms, respecting the HCCI application range. The reduced mechanism is also successfully numerically validated against another more detailed mechanism provided by LLNL. Engine experiments are performed validating this mixture mechanism with respect to the fuel composition containing n-heptane and iso-octane. The influence of the compression ratio and the equivalence ratio is also studied and used to validate the reduced PRF mechanism.

Keywords:

• Auto ignition control
• HCCI engine application
• Influence of fuel composition
• Numerical and experimental validation
• Reduced mechanism kinetics