在一台4缸柴油机上研究预喷策略（预喷率和预喷间隔）对燃烧与排放特性的影响。研究结果表明：与单次喷射相比，采用预喷策略后，最大压力升高率和NOx排放降低，soot、THC和CO排放升高，热效率提高；增大预喷率，预喷放热率峰值、soot、THC和CO排放升高，NOx排放降低；增大预喷间隔，热效率和soot排放降低，最大压力升高率、THC和CO排放升高；改变预喷间隔对NOx排放无明显影响；在小负荷工况下，与单次喷射相比，采用大预喷率和小预喷间隔策略能同时实现柴油机较高热效率和较低NO排放。
The effects of pilot injection strategies on combustion and emission were investigated on a 4cylinder diesel engine, including pilot injection rate and pilotmain interval. The results show that the maximum pressure rise rate and NOx emissions decrease and the soot, THC and CO emissions increase after utilizing the pilot injection strategies. Increasing the pilot injection rate will lead to the increase of peak pilot injection heat release rate, soot, THC and CO emissions and the reduction of NOx emissions. Increasing the pilotmain interval will lead to the reduction of thermal efficiency and soot emission and the increase of maximum pressure rise rate, THC and CO emissions. Changing the pilot interval has little effect on NOx emissions. Compared with the single injection, the adoption of both large pilot injection rate and small pilot interval can achieve high thermal efficiency and low NOx emissions at the same time at low load.
