The Effect of Alcohol-Gasoline Blends on Exhaust Gas Emission Characteristics of Direct Injection Spark Ignition Engines

Abstract

This study investigates the impact of alcohol-gasoline blends on the emission of harmful pollutants, including carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) from Direct Injection Spark Ignition (DISI) engines. With increasing global concerns over air pollution and the depletion of fossil fuels, alternative fuels such as alcohols have gained attention due to their renewable nature and lower carbon footprint. D-optimal Response Surface Methodology (RSM) design of Design Expert Software (13.0.1) with two factors (engine speed and engine load) and three responses (CO, HC and NOX emissions) was used for the experimental design to determine the effect of alcohol-gasoline (methanol-ethanol-butanol-gasoline) blends on the exhaust gas emission characteristics of DISI engine. Four-stroke, single-cylinder DISI engine which was connected to a hydraulic dynamometer together with instrumentation panel and fuelled with pure gasoline, and two alcohol gasoline blends were used. The best fit model for each response was selected and analysis of variance was applied for a better understanding of model attributes. Results indicate that alcohol-gasoline blends lead to a significant reduction of 49.94% in HC emission, a 47.76% reduction in CO emission and a marginal increase of 0.79% in NOx emission compared to pure gasoline. Statistical analysis showed that all the models and model terms are significant and can therefore be used for accurate prediction. This study concludes that alcohol-gasoline blends present a viable option for reducing harmful emissions in DISI engines, but careful optimization of blend ratios and engine parameters are essential to balance performance and environmental impact.