Effect of nanoparticles on DI-CI engine characteristics fueled with biodiesel–diesel blends—A critical review

In this study, the methods of converting raw non-edible oil into fuel for a diesel engine are discussed. Methods of preparation of nanoparticles like sol–gel, hydrothermal, homogenous addition and sonication methods are reviewed. The effect of nanoparticles doped with biodiesel–diesel blends on engine performance (specific fuel consumption and brake thermal efficiency) and combustion parameters (cylinder peak pressure rise and heat release rate) is presented. Moreover, the emission characteristics (carbon monoxide, unburned hydrocarbon, oxides of nitrogen and smoke emissions) on the use of biodiesel doped with nanoparticles are also discussed. This review indicates that nanoparticles doped with biodiesel diesel blends enhance rapid evaporation, provide better air–fuel interaction and allow more fuel to react with oxygen. As a result, DI-CI engine performance and combustion characteristics are improved and the emission levels are reduced. Therefore, it is one of the eco-friendly fuel technologies for DI-CI engine without any major modifications. Overall, this article would be beneficial for those doing research in the biodiesel manufacturing industries, nanotechnology and pollution control board. Graphical abstract