Advanced Combustion Operation in a Compression Ignition Engine

In this study, advanced combustion operating modes were investigated on a DDC/VM Motori 2.5 L, four-cylinder, turbocharged, common rail, direct-injection light-duty diesel engine, with exhaust emission being the main focus. The engine was operated under a partially premixed charge compression ignition (PCCI) mode, referred to as high-efficiency clean combustion (HECC), in which NOx and PM emissions dramatically decreased while fuel economy was maintained. In comparison to the default baseline operation at the given speed and load, the HECC mode reduced brake-specific NOx emissions by 72.1%, reduced brake-specific NO emissions by 83.2%, reduced brake-specific NO2 emissions by 33.8%, increased brake-specific HC emissions by 73.9%, increased brake-specific CO emissions by 105.6%, increased brake-specific CO2 emissions by 55.9%, reduced brake-specific PM emissions by 80.7%, and reduced brake-specific fuel consumption by 3.6%. The particle size distribution in the vicinity of the HECC operating mode consists almost entirely of an organic aerosol, and the solid phase of the particles becomes vanishingly small.