Effect of ammonia/hydrogen mixture ratio on engine combustion and emission performance at different inlet temperatures

Ammonia fuel is considered one of the most promising zero-carbon fuels. However, ammonia fuel's ignition and combustion performance are poor, and the autoignition temperature is high. Mixing hydrogen fuel and increasing the inlet air temperature is one of the effective methods to realize the ammonia engine. The purpose of this paper is to research the effect of ammonia/hydrogen mixture ratio with engine combustion and emission performance at different inlet temperatures. At the four intake temperatures of 476K–551K, we set the ammonia-hydrogen fuel mixture ratio of 0–90% to study the changes in engine combustion and emission performance. The research shows that in the hydrogen ignition mode when the intake air temperature is 476K, and the hydrogen mixing ratio is 30%, the engine power is the highest, and the KI value is slightly greater than 2MPa/°CA. Fewer parts do negative work, the overall engine performance is the best, the ammonia escape phenomenon is eliminated, and the emission performance is better. A hydrogen/ammonia blended fuel is the best solution to achieve zero-carbon combustion. The research results can promote the development of ammonia/hydrogen engines and promote the internal combustion engine towards zero-carbon combustion mode.