Application of Narrow Cone Angle Injectors to Achieve Advanced Compression Ignition on a Mass-Production Diesel Engine - Control Strategy and Engine Performance Evaluation

Advanced compression ignition combustion system which reduces simultaneously both nitride oxides (NOx) and particulate matter (PM) is a promising approach to meet future emission regulations. In order to achieve advanced compression ignition, flexible fuel injection is required for ultra-early and post-TDC injections, which conventional injector fails to accomplish due to wall-wetting effect. In this work, special injectors with the spray angle of 60 degree are applied on a 4 cylinder mass-production diesel engine without modification of the engine configuration. For application-oriented study, sweep experiments of injection timings and durations, fuel injection pressure and the boost pressure are carried out to investigate the relationships between the control parameters and the engine performance. Model based calibration and real application tests validate the maximum applicable operation range of maximum speed of 2200 RPM and IMEP of 8.0 bar. Evaluation result shows that narrow cone angle injector is capable to achieve very low NOx (<100ppm) and smoke (>0.01 m^-1) emissions without much penalty of the fuel consumption within certain engine operation range. This engine with prototype advanced combustion system is developed to be applied in a mild hybrid power system framework.