喷油时刻对柴油机富氧燃烧颗粒物排放特性的影响

Effects of Injection Timing on Particulate Emissions in Oxygen-Enriched Combustion Diesel Engine

为改善柴油机颗粒物排放问题,进行了柴油机富氧燃烧的试验.通过一台单缸高压共轨柴油机在不同的进气氧体积分数条件下研究了预喷时刻和主喷时刻对柴油机颗粒物排放的影响.采用DMS500型快速颗粒光谱仪测试分析了柴油机富氧燃烧排放颗粒物的数量浓度、质量浓度、粒径分布和几何平均直径.结果表明:随着预喷时刻提前,颗粒物数量浓度和质量浓度变化范围不大,几何平均粒径略有增大;随着主喷时刻推迟核态数量浓度减小,凝聚态数量浓度增加,颗粒物质量浓度增大,凝聚态质量浓度和几何平均粒径增大;进气氧体积分数增加,核态数量浓度增大,凝聚态数量浓度减少,颗粒物质量浓度下降,几何平均粒径减小.

To reduce the particulate emission of diesel engine, the oxygen-enriched combustion was studied in a die- sel engine. The effects of pilot injection timing and main injection timing on particulate matter （PM）emissions were experimentally investigated in a one-cylinder common rail light-duty diesel engine. Particle number （PN） concentra- tion, particle mass concentration, particle size distribution and geometric mean diameter were measured with a fast particle analyzer （DMSS00） under steady-state engine operating conditions. Results indicate that, with the advance of pilot injection timing, PN and particle mass changes little and geometric mean diameter increases slightly. With the delay of main injection timing, the number concentration of nucleation mode PM is decreased, the number concen- tration of accumulation mode PM is increased, the mass concentration of PM is increased, the mass concentration of accumulation mode PM increases and geometric mean diameter are increased. With the increase of intake oxygen con- centration, the number concentration of nucleation mode PM is increased, the number concentration of accumulation mode PM is decreased, the mass concentration of PM decreases and geometric mean diameter are decreased.