Combustion performance of rubber seed methyl ester using aromatic and phenolic antioxidants in a multi-cylinder diesel engine

This paper analyzes the effect of antioxidants on engine combustion performance of a multi-cylinder diesel engine fueled with rubber seed biodiesel blends. Four antioxidants, namely 2-tert-butylbenzene-1,4-diol, N,N′-diphenyl-1,4-phenylenediamine, 2(3)-tert-Butyl-4-methoxyphenol and N-phenyl-1,4-phenylenediamine, were added at concentrations of 1000 and 2000 ppm to rubber seed biodiesel blends. Antioxidants blends increased the brake power by 4.21% and decreased the brake-specific fuel consumption by 6.82% compared to base biodiesel blends. The NO emissions reduction percentage for antioxidants fuels was 9.78% compared to base line biodiesel. However, the treated biodiesel blends increased carbon monoxide, hydrocarbon and smoke opacity up to 32.20, 42.15 and 43.92%, respectively, compared to non-treated blends. Compared to diesel fuel, antioxidants fuels decreased the brake power and increased the brake-specific fuel consumption, cylinder pressure and heat release rate. But compared to biodiesel blends, the cylinder pressure and heat release rate with antioxidants were reduced by 4.17 and 6.87%, respectively. It can be concluded that antioxidants addition is effective in increasing the oxidation stability and controlling the NO emissions of rubber seed biodiesel fueled diesel engines.