A comprehensive review on advancement and challenges of renewable biofueled reactivity controlled compression ignition (RCCI) engine

The widespread adoption of compression ignition engines in major industries such as agriculture, electric power production, and transportation has caused an increase in fossil fuel consumption, resulting in a fossil fuel energy crisis, environmental degradation, escalating fuel prices, and global warming. Moreover, nitrogen oxides and smoke emissions from diesel engines remain a vital issue for researchers. Hence, to alleviate the use of fossil fuels and to diminish emissions, researchers are tirelessly establishing numerous strategies. Low temperature combustion (LTC) is one such promising advanced combustion strategy. Although LTC is achieved in many ways, the reactivity controlled compression ignition (RCCI) approach is reported to be more effective from the perspective of combustion phasing control, high efficiency, and near-zero emissions. However, the RCCI engine encounters increased concentrations of hydrocarbon and carbon monoxide emissions and a higher rate of pressure rise, which restrict their range of operation and commercialization. From another research perspective, biofuels like alcohol and biodiesel offer carbon-neutral, renewable, sustainable, biodegradable, and lower emissions than fossil fuels. Furthermore, the use of biofuels in RCCI operations has demonstrated improved performance and reduced emissions. Hence, in this work, the review is centered on recent research on RCCI engines with sustainable biofuel and highlights the challenges involved in operating and commercializing these engines. This review would facilitate engine researchers to explore the features of a biofueled reactivity-controlled compression ignition engine.