Assessing performance variability in a dual-fuel diesel engine using diesel and biogas: an experimental study across different compression ratios

Abstract The increasing concerns about energy security and environmental sustainability have intensified the search for alternative fuels. This study investigates the performance and emission characteristics of a dual-fuel diesel engine utilizing purified biogas and diesel across various compression ratios. A single-cylinder, direct-injection, water-cooled, variable compression ratio diesel engine was adapted to operate in dual-fuel mode, running experiments at compression ratios of 12, 14, 16, 18, and 20 with a constant injection timing of 23° before top dead center under different load conditions. The study reveals a peak brake thermal efficiency of 33.25% at a compression ratio of 20, demonstrating the potential of biogas as a viable alternative fuel. Notably, while carbon monoxide and hydrocarbon emissions decreased with higher compression ratios, nitrogen oxide emissions increased, highlighting a trade-off in emission characteristics. This work contributes to the understanding of biogas utilization in diesel engines, offering insights into optimizing engine performance and emissions through compression ratio adjustments. The findings can inform future developments in sustainable energy solutions.