Performance, emission and combustion characteristics of a diesel engine fuelled with diesel/coconut shell oil blends

Abstract

In this work the coconut shell oil (CSO) - diesel blends are utilized in a compression ignition (CI) engine and its performance, combustion and emission behaviour are analysed with different loading conditions. The coconut shell oil is extracted from coconut shells by the pyrolysis method conducted in an oxygen-free environment with different processing temperatures. The extracted fuel was tested in a single-cylinder, four-stroke, direct-injected (DI) diesel engine with different diesel/coconut shell oil blends (CSO20, CSO40, CSO60, CPO80 and CSO100). During the experimentation, the engine was operated with a constant speed of 1500 rpm and an injection pressure of 250 bar at 23 deg before TDC. The result of this study is clearly showing that the neat coconut shell oil and its blends could be used effectively in diesel engines with better thermal efficiency and exhaust pollutants. It is found that the total fuel consumption by the diesel engine is increased with the presence of CSO in the blends. The blend of CSO20 has registered a lower fuel consumption rate compared to other blends, due to its high heating value. The brake thermal efficiency (BTE) of diesel engines operated with CSO and its blends have registered lower values compared to diesel fuel. The blend of CSO20 has resulted with high heat release rate (HRR) and in-cylinder pressure compared to other blends. The exhaust pollutants like carbon monoxide, hydrocarbon and smoke from CSO blends were registered at different values based on the presence of CSO in the blends. The blend of CSO20 has produced lower pollutants compared to other blends, which is nearer to the values of diesel fuel. The blends of CSO80, and CSO100 produced lower NOx emissions compared to neat diesel and other blends.