Effect of di-tertiary-butyl peroxide additive on combustion, performance and emissions of a karanja methyl ester fueled diesel engine

Abstract The present work studies the influence of di-tertiary-butyl peroxide (DTBP) as a cetane-improving additive to karanja methyl ester (KME) on the combustion, performance and emission characteristics of a diesel engine. KME produced by base catalyzed transesterification of non-edible karanja oil was blended with DTBP in different volume proportions to result KMED1 (99% KME + 1% DTBP), KMED2 (98% KME + 2% DTBP), KMED3 (97% KME + 3% DTBP) and KMED5 (95% KME + 5% DTBP) fuel blends. With increase in DTBP content, viscosity was reduced, whereas the cold flow properties, cetane index and calorific value were enhanced. Engine test results exhibited improvement in brake thermal efficiency and brake specific energy consumption for all blends compared to neat KME. Combustion analysis showed improved combustion with rise in DTBP content in the blends. The CO, HC and NOx emissions with KME-DTBP blends were less compared to neat KME and the same significantly reduced with rise in DTBP percentage in the blends. This shows improved combustion due to more oxygen availability and improvement in fuel properties with addition of DTBP to KME. However, the NOx emissions were marginally higher with KME-DTBP blends compared to neat KME and diesel that may be further studied.