Numerical Investigation of Ducted Fuel Injection Strategy for Soot Reduction in Compression Ignition Engine

The ducted fuel injection strategy is a method that significantly reduces soot emissions in direct injection compression ignition engines. Fuel is injected into the combustion chamber through a duct enhancing the air-fuel mixture. It guarantees more efficient combustion and less soot formation by reducing the equivalence ratio at the autoignition zone inside the combustion chamber. The effects of the duct fuel injection on the performance, combustion, and emission of the compression ignition engine were numerically investigated in this study. The duct geometries with varying diameters, lengths, and stand-off distances were examined to find the most appropriate size using an experimentally validated CFD model and detailed soot model. Results show that up to 66.7% reduction in soot emissions were observed with the usage of the ducted fuel injection strategy compared to conventional diesel combustion. In addition to reducing soot emissions, the ducted fuel injection strategy decreased CO and HC emissions by 20.4% and 7.8%, respectively. While the ducted fuel injection strategy reduces emissions, it does not decrease engine performance; on the contrary, it increases gross IMEP by 0.58%.