EXPERIMENTAL INVESTIGATION OF A HYDROGEN-ENRICHED RCCI ENGINE FUELED WITH MICROALGAE BIODIESEL

The present study examines the impact of hydrogen induction on the performance and emission attributes of a Reactivity Controlled Compression Ignition (RCCI) Engine operating on a microalgae biodiesel–diesel blend (B20D80) with a constant injection timing of 23° BTDC and an injection pressure of 200 bar. Experiments were conducted with hydrogen induction at flow rates of 3, 6, and 9 lpm, referred to as B20D80 + H? 3 lpm, B20D80 + H? 6 lpm, and B20D80 + H? 9 lpm, respectively. Among the tested fuel combinations, the B20D80 + H? 9 lpm blend showed improved performance under these fixed injection conditions, achieving a 20.8% enhancement in brake thermal efficiency and a 28.1% decrease in brake specific fuel consumption compared to conventional diesel operation. Emission analysis indicated that hydrogen enrichment led to substantial reductions in major pollutants, carbon monoxide, and smoke opacity, decreasing by 24% and 25%, while carbon dioxide and hydrocarbon emissions were reduced by around 8.6% and 35%, owing to the carbon-free nature of hydrogen and the oxygenated structure of biodiesel. However, nitrogen oxide emissions increased moderately by 22.8%, which is due to higher in-cylinder temperatures resulting from enhanced combustion. Overall, the results demonstrate that hydrogen-assisted microalgae biodiesel operation significantly improves combustion efficiency while effectively reducing most exhaust emissions, highlighting its viability as a cleaner, more efficient dual-fuel strategy for RCCI engines.