MMT对GDI、PFI汽油机微粒排放的影响

为研究MMT对GDI、PFI汽油机微粒排放数量浓度以及质量浓度的影响,利用DMS500快速型微粒光谱仪,对一台增压缸内直喷(GDI)汽油机和一台自然吸气式气道喷射(PFI)汽油机燃用基础油以及在基础油中添加有机锰(MMT)的燃油的微粒排放特性进行了试验研究.结果表明:MMT的添加均会增加GDI、PFI汽油机的微粒排放,燃用不同含Mn量的燃油,各负荷下GDI汽油机的微粒数量浓度均明显高于PFI汽油机.中小负荷下GDI、PFI汽油机微粒排放数量浓度以及质量浓度均随着Mn含量的增加而上升.大负荷下,PFI汽油机微粒数量浓度随着Mn含量的增加而上升,但GDI汽油机则是在燃用不含Mn的燃油时微粒数量浓度最低,而后随着燃油中Mn含量的增加,超细微粒数量浓度的峰值反而逐步降低.GDI、PFI汽油机核模态与积聚模态微粒数量变化的规律相似.

Effect of MMT gasoline additive on PM emissions from a GDI and PFI gasoline engine

In order to understand the effect of the organometallic antiknock additive MMT(methylcyclopentadienyl manganese tricarbonyl) on PM(particulate matter) mass and number concentrations from GDI (gasoline direct injection) and PFI (port fuel injection) gasoline engine,PM emissions were measured from a turbocharged GDI gasoline engine and a naturally aspirated PFI gasoline engine operating on a baseline fuel or the baseline fuels blending with different ratios of MMT. The measurements were conducted by means of DMS500 analyzer with fast response particulate. Measurement results showed that,compared with baseline fuel,the addition of MMT could increase PM emissions from both GDI and PFI gasoline engine. PM number concentrations from GDI gasoline engine was consistently higher than that of PFI gasoline engine operating on fuels with different MMT contents under different loads. As the MMT content of fuels increased,PM mass and number concentrations from GDI and PFI gasoline engine both increased under small and medium loads. At high load, PM number concentrations from PFI gasoline engine increased with the MMT content of fuels, but for GDI gasoline engine, its PM number concentrations were the lowest while operating on MMT-free gasoline, then the peak number concentrations of micro-particle decreased with the MMT content of fuels. The number of nucleation and accumulation mode PM from GDI and PFI gasoline engine followed the same trend.