COMPUTATIONAL STUDY OF PARTIAL FUEL STRATIFICATION FOR HCCI ENGINES USING GASOLINE SURROGATE REDUCED MECHANISM

Abstract

Fuel stratification is a potential strategy for reducing the maximum pressure rise rate in HCCI engines. Simulations of partial fuel stratification (PFS) have been performed using a modified version of KIVA-3 V that computes chemistry using CHEMKIN. A novel 96-species reduced mechanism for a four-component gasoline surrogate has been developed from a 312-species skeletal mechanism given by Mehl et al. (2011) using the Computer Assisted Reduction Mechanism algorithm (the detailed mechanism from Lawrence Livermore National Laboratory has about 1400 species and 6000 reactions). The reduced mechanism is validated for ignition delay against the detailed mechanism and experimental shock tube data. Simulations of PFS and homogeneous charge compression ignition (HCCI) engine operation using the gasoline surrogate and PRF73 were performed for a cooperative fuel research (CFR) engine of compression ratio 14:1 at ambient and boosted intake pressures. Analysis of numerical results reveals that the temperature distribution of the mixture stratification dictates whether single-stage or multi-stage combustion is observed for PFS.

Keywords:

• Fuel stratification
• Gasoline
• HCCI
• Reduced mechanism
• Surrogate

ACKNOWLEDGMENTS

The authors would like to thank Gregory Chin for developing the computational grid of the CFR engine.

Notes

Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/gcst.