Achieving Euro 7 WHSC NOx emission targets from a Spark ignited engine using Methanol-Hydrogen co-fuelling.

E-methanol is increasingly seen as a promising clean fuel because its chemical makeup is close to fossil fuels, making it easier to use in existing engines. It offers a carbon-neutral option to help reduce greenhouse gases in sectors where cutting emissions is especially difficult, such as transportation. However, while e-methanol avoids adding new carbon dioxide, burning it in internal combustion engines still releases harmful gases like NOx and other toxic by-products like formaldehyde and formic acid that damage both health and the environment. This report explores a new strategy that combines methanol with hydrogen to run engines under “ultra-lean” conditions and its impact on emissions, performance and efficiency. Experiments were carried out on a single-cylinder spark ignition engine, with directly injected methanol and port fuelled injection of hydrogen. The findings show that adding about 15% hydrogen at low engine loads can extend the lean limit from λ=1.7 to λ=2. This change cut NOx emissions by 99% and reduced formaldehyde emissions by 18% compared to standard methanol operation. At higher loads, only 4% hydrogen was needed to see similar benefits. The trade-off, however, is that under these lean conditions, other pollutants such as unburned hydrocarbons tend to rise. This means that while hydrogen co-fuelling is an effective way to drastically lower NOx and unregulated toxic emissions, further optimization is needed to balance all pollutants.