An Efficient and Unified Combustion Model for CFD of SI and CI Engine Operation

Mianzhi Wang, Suya Gao, Chia-Fon Lee

Research output: Contribution to journalConference articlepeer-review


In this work, an efficient and unified combustion model is introduced to simulate the flame propagation, diffusion-controlled combustion, and chemically-driven ignition in both SI and CI engine operation. The unified model is constructed upon a G-equation model which addresses the premixed flame propagation. The concept of the Livengood-Wu integral is used with tabulated ignition delay data to account for the chemical kinetics which is responsible for the spontaneous ignition of fuel-air mixture. A set of rigorously defined operations are used to couple the evolution of the G scalar field and the Livengood-Wu integral. The diffusion-controlled combustion is simulated equivalent to applying the Burke-Schumann limit. The combined model is tested in the simulation of the premixed SI combustion in a constant volume chamber, as well as the CI combustion in a conventional small bore diesel engine. The result shows satisfactory accuracy of the predicted cylinder pressure and heat release rate, while maintaining low computational cost. The combined model provides a natural, robust, and efficient solution to two difficult tasks in development-oriented computational-power-constrained engine simulation: a) to predict SI knock in G-equation simulation; b) to account for the CI induction time in spray combustion simulation at the Burke-Schumann limit.

Original languageEnglish (US)
JournalSAE Technical Papers
Issue numberMarch
StatePublished - Mar 28 2017
EventSAE World Congress Experience, WCX 2017 - Detroit, United States
Duration: Apr 4 2017Apr 6 2017

ASJC Scopus subject areas

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering


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