Experimental Investigation of Different Blends of Diesel and Gasoline (Dieseline) in a CI Engine

Combustion behaviour and emissions characteristics of different blending ratios of diesel and gasoline fuels (Dieseline) were investigated in a light-duty 4-cylinder compression-ignition (CI) engine operating on partially premixed compression ignition (PPCI) mode. Experiments show that increasing volatility and reducing cetane number of fuels can help promote PPCI and consequently reduce particulate matter (PM) emissions while oxides of nitrogen (NOx) emissions reduction depends on the engine load. Three different blends, 0% (G0), 20% (G20) and 50% (G50) of gasoline mixed with diesel by volume, were studied and results were compared to the diesel-baseline with the same combustion phasing for all experiments. Engine speed was fixed at 1800rpm, while the engine load was varied from 1.38 to 7.85 bar BMEP with the exhaust gas recirculation (EGR) application. Results show that, compared to the diesel baseline, the total particle number concentration of G50 was reduced by up to 50% and 90% and count median diameter (CMD) was reduced by 25% and 75% at medium and low loads respectively. The G50 blend had the lowest smoke emission level (0.5 FSN) for all tested load conditions. NOx emissions decreased by 50% at low load and increased by 20% at medium load for G50 compared with the diesel. Compared to diesel, Dieseline led to lower in-cylinder pressure rise and heat release rate peaks at low loads and it prolonged the combustion delay by up to 7 angles compared to the diesel-baseline condition. Dieseline proved to be an attractive fuel for improving the premixed combustion in CI engines.