Abstract: In hydrogen/diesel engine, pre-mixture of hydrogen and air is ignited by diesel oil for the purpose of quasi-homogeneous and low-temperature combustion. The spray atomization of diesel oil in the hydrogen/air environment will influence the distribution of diesel vapor in the cylinder and the combustion progress of the internal combustion engine, and determine the degree of quasi-homogeneous combustion. The spray atomization is the key point to the low-temperature combustion of engine. The spray atomization characteristics of diesel oil in the hydrogen/air environment are studied by using the KIVA-3V code. The research results show that hydrogen in the air can promote the atomization of the diesel oil spray, increase the mass of diesel vapor at the end of oil injection, influence the deflection and the penetration distance of the spray, can reduce the collision intension of the spray particles against the cylinder wall to some extent and facilitate the well-proportioned oil vapor distribution in the cylinder. But the collision probability of the spray particle against the cylinder wall will increase when the hydrogen concentration in the air exceeds a certain limit.

Key words: Diesel oil, Hydrogen, Hydrogen/diesel engine, Simulation, Spray atomization