Analysis on combustion of a hydrogen-blended gasoline engine at high loads and lean conditions

This paper analyzed the combustion characteristic of a hydrogen-blended gasoline engine running at high loads and lean conditions. The cycle-to-cycle variation in indicated mean effective pressure, cylinder pressure during combustion, heat release fraction and exhaust emissions at different conditions were experimentally investigated. The results showed that the addition of hydrogen was able to improve the engine stability through reducing the cyclic variation in indicated mean effective pressure. Moreover, the fuel heat release rate and peak cylinder pressure were accelerated after the hydrogen addition. Both HC and CO emissions were reduced significantly after the hydrogen blending. NOx emissions were slightly increased after the hydrogen addition due to the high flame temperature of hydrogen.