缸内直喷汽油机颗粒排放的热物理特性研究

为了研究缸内直喷汽油机颗粒的热物理特性,基于某发动机试验台架设计了二级热稀释系统。采用EEPS3090粒谱仪对不同稀释比、加热温度、蒸发温度下的颗粒粒径分布和浓度进行了试验研究。试验结果表明:不同稀释比下颗粒数量浓度随粒径的增大呈现对数正态双峰分布,不同加热温度和蒸发温度下颗粒数量浓度随粒径增大呈现三峰分布;较大稀释比对核态数量总浓度影响较大,加热温度高于200℃后颗粒数量浓度趋于稳定,蒸发温度对积聚态颗粒有较大影响。

Thermal Physical Property of Particulate Emission for Gasoline Direct Injection Engine

To analyze the thermal physical property of GDI engine ,a two-stage thermo-dilution system was developed .The particle size distribution and concentration were measured under different dilution ratios ,heating temperatures and evaporation temperatures with the EEPS 3090 particle size spectrometer .The results show that the concentration of particle number shows a lognormal bimodal distribution under different dilution ratios and shows trimodal distribution under heating temperatures and evaporation temperatures with the increase of particle size .Moreover ,large dilution ratio has great influence on the total con-centration of nuclear mode particle number ,heating temperature higher than 200 ℃ makes the concentration of particle number stable and evaporation temperature has important influence on accumulation mode particle number .