An Investigation Of Ethanol Fuelling For Compression Ignition Engines

Energy shortage and environmental pollution have become a difficult problem in the world. Diesel engine has been widely applied in the transportation sector due to the high thermal efficiency and reliability. But the high NOx emission produced in the diffusion combustion of diesel engine is a big obstacle in the development of the diesel engines. Ethanol used as renewable oxygenated biofuel can improve the NOx emission and decrease the harmful emission of diesel engine and it has received extensive attention at home and abroad recently.The research is conducted in common rail diesel engine,and studied and analyzed the influence of ethanol blended water on the dynamic performance,economy performance and emission performance before and after DOC with diesel/ethanol compound combustion.The torque gained in the DECC mode with ethanol blended water is lower than that in the baseline engine in low speed,while slightly higher than the average torque of the baseline engine in medium-high speed.The brake specific fuel consumption rate in the DECC mode with ethanol blended water is higher in low speed and a little lower in the middle-high speed in comparison with that in the baseline engine.The Fourier transform infrared spectrometer (FTIR), an advanced measure method is used to investigate and compare the emission performance between the baseline engine and the DECC mode with the ethanol blended with 30%, 40% and 50% water The results show that before DOC the NOx present a reduction trend as the blending ratio of water and ethanol increases. Furthermore, the addition of the ethanol blended water remarkably increases the CO, HC, formaldehyde and acetaldehyde emissions. After DOC, the NOx emission almost keeps the same level, the emissions of HC, CO and formaldehyde are reduced to the same level or even lower than the baseline engine before DOC, while DOC have no influence on the acetaldehyde emissions at the load of 25% in middle and high speed. And the smoke opacity in the DECC mode is lower than that in baseline engine except the operating conditions of full load.Ethanol blended water can be used as a clean and efficient alternative fuel for diesel engines with the DECC mode combined with DOC. It can partially substitute diesel fuel and effectively reduce the harmful pollutants while keep the same power and economy.