DOC+CDPF配方对柴油公交车颗粒物排放特性影响

为研究不同DOC+CDPF（催化型连续再生颗粒捕集器）配方对公交车颗粒物排放特性的影响，以一辆满足国Ⅲ排放的柴油公交车为试验样车，在重型底盘测功机上分别进行了加装3种不同DOC+CDPF的柴油机在中国典型城市公交车循环（CCBC）中的排放特性试验，分析了不同贵金属负载量对柴油机颗粒物排放特性的影响.结果表明：在相同贵金属配比情况下，当DOC+CDPF催化剂配方中贵金属负载量较高时，颗粒物浓度降幅较大.3种方案的颗粒物质量浓度综合减排率分别为99.3%、98.8%、96.4%，平均降幅达到98.2%；当使用DOC+CDPF后，柴油机颗粒物粒径分布由双峰对数分布变为三峰对数分布，但不同催化剂配方下对应的粒径最大峰值点会偏移；采用DOC+CDPF装置后，发动机排放背压略有增加.且当贵金属负载量越高时，装置压降增量越少，被动再生性能越优异.

Effects of formulations of DOC+CDPF on characteristics of particle emission from a diesel bus

To study the impacts of formulations of DOC+CDPF on characteristics of particle emission from a Diesel Bus, a China-Ⅲ diesel bus with three different DOC+CDPF diesel engines were tested on heavy chassis dynamometer under China typical cities bus driving cycle (CCBC). The results showed that the mass concentration of PM was lower when precious medal load in DOC+CDPF catalyst was increased with the same ratio of proportion. The decrease of mass concentration of three recipes are 99.3%, 98.8% and 96.4% respectively, by an average of 98.2%. After using DOC+CDPF, particle size distribution of particulate matter changed from bimodal lognormal distribution to tri-modal lognormal distribution and the maximum peak point of corresponding particle size shifted with different catalyst formulations. At the same time, backpressure of engines emission increased slightly. In addition, while the precious metal load went higher, the pressure drop increment became less and the passive regeneration performance improved.