Technical Paper
Optical Investigation of Premixed Low-Temperature Combustion of Lighter Fuel Blends in Compression Ignition Engines
2011-09-11
2011-24-0045
Optical imaging and UV-visible detection of in-cylinder combustion phenomena were made in a single cylinder optically accessed high swirl multi-jets compression ignition engine operating with two different fuels and two EGR levels. A commercial diesel fuel and a lighter fuel blend of diesel (80%) and gasoline (20%), named G20, were tested for two injection pressures (70 and 140 MPa) and injection timings in the range 11 CAD BTDC to 5 CAD ATDC. The blend G20 has a lower cetane number, is more volatile and more resistant to the auto-ignition than diesel yielding an effect on the ignition delay and on the combustion performance. Instantaneous fuel injection rate, in-cylinder combustion pressure, NOx and smoke engine out emissions were measured. Taking into account the particular configuration of the engine, the efficiency was estimated by determining the area under the working engine cycle.