Studies on exhaust emissions in semi-adiabatic compression ignition engine with alternate fuels

Abstract

249-255Alcohols (ethanol and methanol) and a few non-edible vegetable oils are showing a great potential for replacing conventional diesel fuels quite effectively. The low heat rejection semi-adiabatic compression ignition (C.I.) engines are gaining prominence for adopting these alternate fuels. The major pollutants of the exhaust emissions of  C.I. engines are oxides of nitrogen (NOx) and black smoke. When alcohols are used as alternate fuels, the pollutants have to be checked specifically for aldehydes which are carcinogenic in nature. The pollution levels of black smoke, NOx and aldehydes emitted through exhaust of engine are reported here on both conventional and insulated versions of C. I. engines with different proportions of ethanol-diesel and methanol-diesel mixtures. The non-edible vegetable oils crude, and esterified jatropha and pongamia oils are used for total replacement of diesel fuel on both configurations of the engine. The NOx and smoke levels have been found to be lower with both ethanol and methanol induction with both conventional and insulated versions of the engine in comparison to pure diesel operation. Also, production of aldehydes in the form of formaldehyde has been found to increase with both ethanol and methanol operations. However, the insulated version of the engine with ethanol operation helps in reducing formaldehyde emissions of the engine. With the non-edible vegetable oils, generation of smoke is drastically increased in comparison to pure diesel operation. However, with preheating of vegetable oil and increased injection pressure, the smoke levels get reduced and NOx levels increase marginally