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

摘要

Alcohols (ethanol and methanol) and a fewnon-edible vegetable oils are showing a greatpotential for replacing conventional diesel fuelsquite effectively. The low heat rejection semi-adiabatic compression ignition (C.I.) engines aregaining prominence for adopting these alternate fuels.The major pollutants of the exhaust emissions of C.I.engines are oxides of nitrogen (NO_x) and black smoke.When alcohols are used as alternate fuels, thepollutants have to be checked specifically foraldehydes which are carcinogenic in nature. Thepollution levels of black smoke, NO_x and aldehydesemitted through exhaust of engine are reported hereon both conventional and insulated versions of C.I.engines with different proportions of ethanol-dieseland methanol-diesel mixtures. The non-ediblevegetable oils crude, and esterified jatropha andpongamia oils are used for total replacement of dieselfuel on both configurations of the engine. The NO_xand smoke levels have been found to be lower with bothethanol and methanol induction with both conventionaland insulated versions of the engine in comparison topure diesel operation. Also, production of aldehydesin the f6rm of formaldehyde has been found to increasewith both ethanol and methanol operations. However,the insulated version of the engine with ethanoloperation helps in reducing formaldehyde emissions ofthe engine. With the non-edible vegetable oils,generation of smoke is drastically increased incomparison to pure diesel operation. However, withpreheating of vegetable oil and increased injectionpressure, the smoke levels get reduced and NO_x levels increase marginally.