Abstract: Ethanol gasoline, as a low-carbon and sustainable alternative fuel to gasoline, has untapped potential for energy conservation and emission reduction. Select 8 representative operating conditions to study the effects of blending different proportions of ethanol (E10—E100) on the combustion and emission performance of direct injection gasoline engines according to the national ⅥB emission standard. The results show that blending low proportion ethanol gasoline (E10—E50) can improve combustion performance, increase heat release rate, significantly increase combustion speed, and reduce equivalent fuel consumption; Mixing high proportion ethanol gasoline (E85—E100) has poor compatibility with existing gasoline engine technology, resulting in delayed combustion process, significant decrease in combustion temperature and heat release rate, and reduced thermal efficiency. As the proportion of blended ethanol increases, the overall CO and THC emissions show a decreasing trend, while NOx emissions show an increasing and then decreasing trend. Under some operating conditions, the THC emissions of E100 significantly increase, and ethanol gasoline also has high potential for reducing particulate matter emissions.

Key words: gasoline engine, ethanol gasoline, combustion efficiency, equivalent fuel consumption, emission characteristics