Effects of Mixing and Chemical Parameters on Homogeneous Charge Induced Ignition Combustion Based on a Light-Duty Diesel Engine with Ultra-Low NO_x and Soot Emissions and High Thermal Efficiency

摘要

A Homogeneous charge induced ignition (HCII) combustion, realized by in-cylinder fuel blending of gasoline and diesel fuel, was developed and carefully optimized, both on a single cylinder and a multi-cylinder light-duty diesel engines, for high thermal efficiency and near zero emissions in a wide engine-operation range up to IMEP of 1 MPa. The effects of mixing and chemical parameters of HCII combustion, which can be controlled by production-viable hard-ware using conventional gasoline and diesel fuel, include injection timing of diesel fuel, injection rate pattern of diesel fuel (such as split injection), the gasoline/diesel ratio, boost pressure and exhaust gas recirculation (EGR). Based on a single cylinder engine, the experimental result shows that the interaction of the mentioned control parameters plays decisive role in determination of exhaust emissions and thermal efficiency. The coefficient of variability (COV) of IMEP, difference among cylinders, fuel consumption and emissions of the HCII combustion were also examined on a four-cylinder diesel engine. At more than half load, ultra-low NO_x and soot emissions can be achieved with clean HCII combustion. Meanwhile, compared with the original diesel engine, the fuel consumption can be decreased even up to 9%.