Experimental study of castor oil–diesel–n-butanol blends used in a CRDI diesel engine with double injection strategy.

In the present study, experimental investigations were carried out on a diesel engine fuelled with castor oil–diesel–n-butanol blends to determine the combustion characteristics and emissions. In comparison with diesel fuel, the blends represented the retarded start of combustion (SOC), the higher peak in-cylinder pressure and heat release rate, and the shortened combustion duration. The brake-specific fuel consumption of the blends was higher by 7% for CD80B20, and 11% for CD60B40, respectively, whereas the difference of the brake thermal efficiency was less than 3%. The blends exhibited bi-modal particle size distribution (PSD), and diesel showed uni-modal behaviour under all operating conditions. The total number concentration of blends was larger, but the geometric mean diameters were 83, 47 and 40 nm for diesel fuel, CD80B20 and CD60B40, respectively. Nitrogen oxide emissions of the blends were higher by 14% and slightly increased with the growth of n-butanol content in the blends. Carbon monoxide (CO) and hydrocarbon (HC) emissions were decreased at 1000 r/min and increased at 1400 r/min. [ABSTRACT FROM AUTHOR]