Sustainable methane-hydrogen fuel in heavy duty drive cycle

COP26 aims to reduce GHG emissions by 45 % (2010–2030), requiring a shift away from carbon-intensive fuels in heavy-duty (HD) transport. Replacing diesel with natural gas can reduce tailpipe CO2, with further gains possible through partial substitution with H2. The novelty of the current work lies in showing how H2 influences a Euro 6 HD methane engine, using a combined experimental-simulation approach that explicitly converges on cycle-weighted outcomes. This is achieved by integrating experimental testing and validated Chemkin-Pro spark-ignition modelling to evaluate CH4-H2 blends across 60 % of a typical drive cycle to provide system-level insights. H2 substitution levels of 20 % and 28 % by volume were assessed. Experimentally, H2 (20 %) reduced engine-out HC and NOx emissions by 15 %, alongside up to 10 % decreases in CO2 emissions and gravimetric fuel consumption. The Chemkin-Pro multizone simulation was applied to extend the analysis across a wider range of engine speeds/loads, provide a mechanistic interpretation of NOx pathways, and reveal efficiency and emissions trends. The key contribution lies in showing not only whether H2 substitution reduces emissions, but where and under what duty-cycle conditions benefits are maximised or trade-offs emerge. This cycle-anchored, experimentally validated assessment offers valuable guidance for low-carbon powertrain development. Integrated over the drive cycle, the combined results demonstrate that H2 (20 %) can simultaneously reduce engine-out emissions (lowered NOx and HC emissions by 15 %) and deliver 4 % reductions in gravimetric fuel consumption. When combined with a renewable CH4 and H2 supply, this establishes a promising pathway to decarbonise existing engine platforms.