Performance Evaluation of a Diesel Engine Fueled with Methyl Ester of shea Butter

Biodiesel as an alternative fuel for diesel engines has been developed for some three decades now. While it is gaining wide acceptance in Europe, USA and some parts of Asia, the same cannot be said of Africa. With more than 35 countries in the continent depending on imported crude oil, it is necessary to look for alternative fuels which can be produced from resources available locally within any country. Hence this study presents performance of single cylinder diesel engine using blends of shea butter biodiesel. Shea butter was transformed into biodiesel by transesterification process. Tests are conducted to compare the biodiesel with baseline diesel fuel in terms of engine performance and exhaust emission characteristics. The results obtained showed that the addition of biodiesel to diesel fuel decreases the brake thermal efficiency (BTE) and increases the brake specific fuel consumption (BSFC). These results are expected due to the lower energy content of biodiesel fuel. On the other hand while the NOx emissions increased with increase in biodiesel content in the fuel blends, the emissions of carbon monoxide (CO), un-burnt hydrocarbon (UHC) and smoke opacity decreased. The engine performance which indicates that the biodiesel has properties and characteristics similar to diesel fuel and the reductions in exhaust emissions make shea butter biodiesel a viable additive or substitute to diesel fuel