Exhaust Chemistry of Low-NOX, Low-PM Diesel Combustion

The exhaust chemistry of combustion regimes characterized by simultaneous low-NO_X and low-PM emissions were investigated on a Mercedes 1.7-L diesel engine. Two approaches for entering low-NO_X low-PM regimes were explored using a California specification low aromatic certification diesel fuel. Detailed characterizations of gas-phase hydrocarbons, particulate soluble organics, and aldehydes are presented for both approaches. Results indicate significant formation of partially oxygenated hydrocarbons and fuel reformation products during periods of low-NO_X, low-PM combustion.