为了提高柴油-天然气（DN）双燃料发动机在中、低负荷时的燃烧效率，降低一氧化碳（CO）和未燃碳氢化合物（UHC）排放，以D19高压共轨柴油机为研究机型，构建了发动机燃烧室CFD模型，通过3D-CFD耦合柴油天然气氢气（DNH）三燃料化学动力学机理，进行数值模拟，研究了进气掺氢对DN发动机燃烧及排放特性的影响。结果表明：在进气内掺入20%的H₂，可促进缸内关键自由基生成，加快天然气（NG）燃烧速率，使燃烧效率达到95.7%，与不掺H₂时相比提高了11.3%；而掺入25%的H₂，可使总碳氢化合物（THC）减少49.0%，CO降低37.4%，CO₂下降12.7%。

In order to improve the combustion efficiency of dieselnatural gas dual fuel engine at medium and low loads and reduce carbon monoxide (CO) and unburnt hydrocarbon (UHC), the CFD model for combustion chamber was built and the numerical simulation was conducted by using the method of 3D-CFD coupled with diesel-natural gas-hydrogen (DNH) three fuel chemical kinetic mechanism. The influences of intake mixed with hydrogen on combustion and emission characteristics of dual fuel engine were studied. The results show that the in-cylinder key free radical generation improves, the combustion rate of natural gas (NG) accelerates, and the combustion efficiency can reach 95.7%, which increases by 11.3% after adding 20% H₂ into the intake. The addition of 25% H₂ can reduce the total hydrocarbons (THC), CO and CO₂ by 49.0%, 37.4% and 12.7% respectively.