Characteristics of Transient NOx Emission of HEV under Real Road Driving 2020-01-0380
To meet the request of China National 6b emission regulations which will be officially implemented in China, firstly including the RDE emission test limits, the transient emissions on real road condition are paid more attention. Several non-plug-in hybrid light-duty gasoline vehicles (HEV) sold in the Chinese market were selected to study real road emissions employed fast response NOx analyzer from Cambustion Ltd. with a sampling frequency of 100Hz. The concentration of NOx emissions before and after the TWC (Three Way Catalyst) of the hybrid vehicle were also sampled and analyzed, and the working efficiency of the TWC in real road driving process was investigated. It is found that when the engine is at low-speed and heavy-load conditions, especially when fuel is injected after fuel cut, instantaneous spikes in tailpipe NOx emissions could be observed, which means that traffic positions such as crosswalks, speed bumps, high-speed entrances, traffic lights, would lead to higher NOx emissions. At the same time, emissions from PEMS were also recorded and compared with the results from fast response NOx analyzer. Obvious transient effects were revealed and the results could be used for further reducing NOx emissions from automotive RDE and engine calibration of RDE.
Yonghao Zhang, Jun Deng, Qiang Li, Yintong Liu, Bo He, Zongjie Hu, Shi Bo, Liguang Li