Optimization of Skewed Injection for High Swirl, Two-Cycle, Diesel Engine

Generally, two-stroke engines have inherent advantage of higher swirl, as compared to four-stroke engines. Higher swirl helps with better mixing and atomization for mechanical and low pressure, electronic, unit injectors. With the introduction of higher injection pressure, the advantage of swirl reduced to a point in which it started to have a negative impact. In this work, the goal was to optimize a high pressure, common rail injection system for heavy-duty, two-cycle, medium speed, diesel engine (710 cubic inches of displacement per cylinder) under high load. A proprietary multi-dimensional computational fluid dynamic (CFD) code was used for the modeling work. Here, we optimized the new, skewed injection system, which takes advantage of swirl and further helps in atomization of spray. The spray in this study is introduced at a radial angle, which is aligned either along or against the swirl direction. The results showed significant improvement in combustion efficiency. Combustion efficiency is estimated as a decrease in fuel consumption and CO values. Emission parameters, such as nitrogen oxide and soot were also studied and showed significant reductions.