Improved Performance, Combustion and Emissions of SI Engine Fuelled with Butanol: A Review

Several studies on ethanol as a biofuel have been comprehensively carried out. Today, a growing interest in longer chain alcohols has emerged due to their favourable physical and thermodynamic properties. Butanol or butyl alcohol with 4-carbon structure (C4H9OH) is a more promising biofuel as it outweighs methanol and ethanol in several ways. The production cost of butanol has been gradually reduced, and rapid progress in the development of its production technology has allowed butanol to be produced more effectively. However, studies on the effect of butanol on gasoline or spark ignition (SI) engines are not as comprehensive as the abundant research of ethanol. This paper highlights recent novelty and contribution of butanol addition in SI engine. Results of new approaches on the engine's performance, combustion and emission characteristics are summarised. Reviews from this paper suggest that there are some gaps in the addition of butanol found in the literature. Thus, several encounters and forthcoming research directions are outlined in the final section of this review article, highlighting several possible contributions that have not yet been carried out using butanol as a biofuel in a gasoline engine.