Experimental Investigations on Engine Performance and Exhaust Emissions in a HCCI Engine Fuelled with Diesel-Ethanol Fuel Blends

In this study, the effects of diesel-ethanol fuel blends on HCCI engine performance and exhaust emissions were investigated experimentally in a single cylinder, port injection HCCI engine. In the experiments, ethanol and diesel mixtures in different ratios by volume such as 10% ethanol-90% diesel (E10/D90), 20% ethanol-80% diesel (E20/D80), 30% ethanol-70% diesel (E30/D70), 40% ethanol-60% diesel (E40/D60) and 100% diesel (D100) were used as test fuels. A single cylinder Quasa test engine was converted to a HCCI engine, modifying the intake system and the warming inlet air temperature. The experiments were conducted at the engine speed of 1500 rpm and at different engine loads. The inlet air temperatures were selected as 50°C, 60°C, 70°C, 80°C, 90°C and 100°C. The variation of volumetric efficiency, engine torque and power, mean effective pressure, specific fuel consumption, thermal efficiency and the emissions of carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxides (NOx) were investigated in this study. The results showed that the test engine could not be operated at high loads with the increase of the amount of ethanol in the test fuels because of the higher octane number and higher auto-ignition temperature of ethanol. Almost zero NOx emissions were obtained for all test fuels. Consequently, it was seen that diesel and ethanol fuel blends had a remarkable effect on HCCI combustion, engine performance and exhaust emissions.

Keywords: HCCI; diesel-ethanol blends; performance; emission