Effect of Pre-Injection Interval on Combustion Characteristics of Dual-Fuel Engines

In this paper, a three-dimensional numerical simulation platform for methanol cracked gas/diesel dual-fuel engine was constructed based on the three-dimensional simulation software of Computational Fluid Dynamics (CFD), and the effects of different pre-main injection intervals on the combustion and emission characteristics of methanol cracked gas/diesel dual-fuel engine were investigated in the large-load working condition. In the simulation, the pre-main injection interval was increased from 10°CA to 30°CA. The results show that the multiple inj ection strategy with pre-injection can effectively reduce the emissions of Soot, HC and CO with the increase of the pre-main injection interval, but a larger pre-main injection interval will affect the thermal efficiency, and the pressure rise may be too high and lead to the increase of NOx emission. When choosing the pre-main injection interval, 15°CA to 25°CA should be avoided as much as possible, since NOx emissions are relatively high in this region. Low emissions can be achieved by adopting an appropriate pre-main -after-inj ection strategy.