在高强化柴油机提升轨压、缩小孔径的背景下，对3种工况下不同喷孔直径的柴油机燃烧过程进行了试验研究，将燃烧及排放结果进行了对比分析，并通过仿真研究揭示其工作机理。研究表明：单缸机试验过程中，随着孔径从0.30 mm减小到0.25 mm，燃油消耗率和烟度均减小，其中燃油消耗率最多可减小2.5%，烟度可减小63.9%；当孔径从0.25 mm继续减小至0.24 mm，缸内的燃烧过程均有恶化趋势。标定工况的缸内三维仿真表明：孔径对工况的匹配有一定的适用范围，对于超过这一范围的0.24 mm和0.30 mm孔径，燃烧均出现恶化现象，而当孔径为0.25 mm时缸内的油气混合较好、热效率最高，具有最好的燃烧效果。

Under the context of increasing rail pressure and reducing orifice diameter for highly intesified diesel engines, the combustion processes of diesel engines with different injection hole diameters were tested and studied under three operating conditions, the combustion and emission results were compared and analyzed, and their working mechanisms were given through the simulation research. The research results show that both the fuel consumption rate and the soot decrease, the fuel consumption rate reduces by up to 2.5% and the soot reduces by 63.9% as the hole diameter decreases from 0.30 mm to 0.25 mm during the test process of the single-cylinder diesel engine. However, when the hole diameter decreases from 0.25 mm to 0.24 mm, the in-cylinder combustion process shows a consistent deterioration trend. The three-dimensional in-cylinder simulation results under the calibration operating conditions show that the matching of hole diameter to operating condition has a range of application, and the combustion shows a deterioration trend for the hole diameter of 0.24 mm and 0.30 mm beyond this range, while for the hole diameter of 0.25 mm, the fuel and gas mixes well, and the thermal efficiency reaches the highest, therefore the optimal combustion is achieved.