Thermodynamic Implications of Emissions Constraints on SI Combustion

摘要

First-principles thermodynamic model aids in understanding of efficiency effects due to emissions constraints: - Can specify heat release and working fluid; - Captures efficiency contributions of γ and molar expansion. EGR as diluent for stoichiometric SI: - Improve γ, enable higher r_c, reduce heat transfer, dilution limit & stability challenge; - ORNL projects for extending dilution limit via fuels, reforming, and controls. Air as diluent for lean SI: - Larger γ improvement than EGR, NOx challenge; - ORNL projects for optimizing NOx storage and conversion with lean/rich cycling in passive SCR system.