Effect of Ethanol Additives on Combustion and Emissions of a Diesel Engine Fueled by Palm Oil Biodiesel at Idling Speed

Abstract

Biodiesel is known for its high cetane number and high oxygen content among other advantages, but its high viscosity and density are not trivial issues for fuel flow and atomization, especially under idling conditions. Due to low cylinder temperature and incomplete combustion, engine idling is one of the worst operating conditions. As a common fuel additive, ethanol can address some of the shortcomings of biodiesel. This work evaluated the combustion and emission characteristics of different concentrations of ethanol additives on a diesel engine fueled with palm oil biodiesel under idling conditions. The results show that ethanol helps to increase peak cylinder pressure and heat release rate, suppressing the production of certain emissions with a maximum reduction in smoke opacity of 71%.

Keywords

• biodiesel
• ethanol additives
• idling speed
• engine performance
• combustion and emission characteristics