A comprehensive assessment over the environmental impact and combustion efficiency of using ammonia/ hydrogen/diesel blends in a diesel engine

To reduce the dependence on traditional fossil fuels and promote low-carbon emissions, this article takes a four-cylinder four-stroke diesel engine as the research object and constructs a simulation model. It mainly simulates and studies the effects of different ammonia energy substitution rates (AESR) and hydrogen energy substitution rates (HESR) on the combustion and emission characteristics of diesel engines. Under the full load condition, the AESR was simulated within the range of 10 %–50 %. Subsequently, HESR of 0, 2 %, 4 %, 6 %, 8 % at AESR of 10 %, 20 %, 30 %, 40 %, and 50 % are set for further study. The research results indicate that with the increase of AESR, the combustion performance of the engine is improved. The emissions of NOx, CO2, and soot are reduced, but the emissions of unburned ammonia are significantly increased. Adding hydrogen to ammonia-diesel blended fuel can effectively reduce unburned ammonia emissions. Based on the comprehensive analysis results, it is more appropriate to choose a HESR of 4 % when the AESR is 10 %.