直喷式柴油机排放微粒尺寸分布特性

在一台单缸柴油机上用SMPS微粒测量装置测量了不同运转条件(如转速、负荷变动、怠速运行、燃油喷射定时等)下柴油机排放微粒尺寸与浓度分布,分析了柴油机微粒排放尺寸分布和数量浓度的特征及其主要影响因素．结果表明,发动机负荷变化对微粒排放的影响较大,在各种负荷下大部分排放微粒都是碳核模式的超细或纳米尺寸微粒,而质量上以累积模式颗粒占主要部分,发动机冷机起动和怠速运行时产生的大部分排放微粒是碳核模式粒子,喷油提前角对排放微粒浓度和尺寸分布有显著影响．

Characteristics of Diesel Particle Size Distribution of Direct Injection Diesel Engine

By using SMPS(scanning mobility particle sizer),diesel exhaust particle size distribution and total number con- centration were measured in a single-cylinder diesel engine at different operating conditions,such as engine speed,load, cold start,idle operating,and injection timing.The characteristics and effects of particle size distribution and number or volume concentrations emitted from a diesel engine were studied based on a number of experimental data.The results show that for nearly all the operating conditions,engine load has much more influence on exhaust particle than the others;most of the particles exist in the so-called nuclei mode in the size of nano-particles or uhrafine particles,but particle mass exist in the accumulation mode.Most of the exhaust particles exist in nuclei mode during the cold start and idling operation.The start of injection has predominant influence on the particle matter size distribution and number concentration.