Operating strategy for exhaust gas reduction and performance improvement in a heavy-duty hydrogen-natural gas blend engine

Hydrogen-natural gas blends (HCNG) have the advantage of lower emission levels, because of their lean combustion characteristics, compared to a direct injection diesel engine equipped with a high-cost fuel supply system and an aftertreatment system for heavy-duty vehicles. The HCNG engine has superior fuel economy with extension of the flammability limit. However, the performance and emission characteristics vary with the content of hydrogen in fuel gases and the operating strategy at each operating condition.