The impact of hydrogen percentage on the combustion, performance, and emissions of NG-H2-diesel naturally aspirated engine at high engine load

This research involved an experimental investigation of gradually increasing hydrogen (H 2 ) percentage in fuel mixture on the combustion, performance, and emissions of H 2 -natural gas (NG)-diesel naturally aspirated engine at high load (20 kW). A mechanical diesel injection pump (MDIP) automatically controlled the diesel flow. Simultaneously, the NG was supplied with constant pressure and a fully open line, while a flow control valve and flowmeter adjusted the H 2 flow rate. A gas-air mixer was positioned at the intake manifold to supply the engine with NG and H 2 , while the diesel was directly injected. The results indicated that increasing H 2 in the fuel mixture reduces BSFC, CO, THC, and smoke, but increases in-cylinder peak pressure and NO X emissions. The detailed results are valuable and usable for industry implementations and upcoming scientific studies.