Abstract:

Performance and emission characteristics unmodified diesel engines operating on different alternative fuels with smaller blend proportions are comparable with pure diesel operation. But with increased blend proportions due to the associated problems of vegetable oils like high viscosity and low volatility pollution levels increase which however is accompanied by operating and durability problems with the long term usage of engine. This paper discusses the necessary modifications required to overcome the problems associated with unmodified diesel engines like Low heat rejection (LHR),dual fuel mode of operation, Turbocharged engines and EGR engines (exhaust gas recirculation) with different alternative fuels . The energy of the biodiesel can be released more efficiently with the concept of low heat rejection (LHR) engine. LHR engine can be used for improving engine performance when biodiesel is used as an alternative fuel. Low heat rejection engines with vegetable oils may give better performance and lower smoke emissions. Exhaust emissions (NOx and smoke) were improved in dual fuel operation. If direct injection diesel engine is modified to operate with dual fuel operation a reduction of exhaust emissions from diesel engines were investigated

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