In opposed-piston, opposed-cylinder (OPOC) two-stroke diesel engines, the relative\nmovement rules of opposed-pistons, combustion chamber components and injector position are\ndifferent from those of conventional diesel engines. In this study, the combustion and emission\ncharacteristics of the OPOC which is equipped with a common-rail injection system are investigated\nby experimental and numerical simulation. Different split injection strategies involving different\npilot injection/fuel mass ratios and injection intervals were compared with a single injection strategy.\nThe numerical simulation was applied to calculate and analyze the effect of split injection strategies\non the combustion and emission after validation with the same experimental result (single injection\nstrategy). Results showed that using split injection had a significant beneficial effect on the combustion\nprocess, because of the acceleration effect that enhances the air-fuel mixture. Additionally, the\ntemperature of the split injection strategies was higher than that of single strategy, leading to the\nnitrogen oxides (NOx) increasing and soot decreasing. In addition, it has been found that the split\ninjection condition with a smaller pilot injection/fuel mass ratio and a medium injection interval\nperformed better than the single injection condition in terms of the thermo-atmosphere utilization\nand space utilization.
Loading....