A Comparative Study of Performance, Combustion and Emissions of Diesel, Jatropha Methyl Ester and Karanj Methyl Ester in a DI-CI Engine

Biodiesel produced from different vegetable oils and fats are likely to have some comparative advantages and disadvantages. Two major oil varieties, considered suitable for biodiesel making are ‘Jatropha curcas’ and ‘Pongamia pinnata’. This study targets at making a comparison of the methyl esters of these oils in a diesel engine vis-a-vis diesel fuel. The performance of the fuels was evaluated in terms of thermal efficiency, specific fuel consumption, power output and mean effective pressure, cylinder pressure, rate of pressure rise and heat release rates. The emissions of carbon monoxide (CO), carbon dioxide (CO2), unburnt hydrocarbon (HC), oxides of nitrogen (NOx) and Smoke opacity with the three fuels were also compared. Both the varieties of the oil, after transesterification, exhibit the major properties within acceptable limits of biodiesel standards set by many countries. Karanj methyl ester (KME) performed better than Jatropha methyl ester (JME) whereas shortest ignition delay is observed with JME. Both the esters performed poorer than diesel but emissions of HC, NOx and smoke were found lower with esters. The three fuels delivered almost same brake power even when the indicated power was higher with diesel.