As the population and urbanization keep on growing at a rapid pace, fuel demands increase, and at the same time the natural fossil fuel resources are also depleting. To reduce the dependence on fossil fuel especially in transportation sectors, a more renewable source of energy, which is biodiesel is being implemented for various application in diesel engine. Biodiesel is capable of producing comparable engine performance as the mineral diesel. However, there are some arising problems including deposits issue, increased in emissions, and deterioration of overall engine performance when fuelled with biodiesel. In this study, a review of the deposits growth in the engine combustion chamber parts and its consequence impacts on the engine emissions and mechanical performance was carried out. Deposits existence and mechanism in the engine parts such as the injector nozzles and piston top, engine emissions such as hydrocarbon, carbon oxide, and nitrogen oxide, and engine mechanical performance such as the brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) were mentioned. Moreover, the experimental methods to investigate the performance of biodiesel and its comparison with ordinary diesel fuel were also presented in this paper. Finally, drawbacks of biodiesel need to be further investigated and understood in the future researches as biodiesel could become the primary replacement for petroleum diesel fuel worldwide.
