Weifang University of Science and Technology, Weifang 262700, China; National Lab of Auto Performance and Emission Test, School of Mechanical and Vehicular Engineering, Beijing Institute of Technology, Beijing 100081, China.
National Lab of Auto Performance and Emission Test, School of Mechanical and Vehicular Engineering, Beijing Institute of Technology, Beijing 100081, China.
J Environ Sci (China). 2021 Aug;106:182-193. doi: 10.1016/j.jes.2021.01.021. Epub 2021 Feb 5.
In this study, ammonia emissions characteristics of typical light-duty gasoline vehicles were obtained through laboratory vehicle bench test and combined with New European Driving Cycle (NEDC) condition and Worldwide Harmonized Light Vehicles Test Cycle (WLTC) condition. The influence of ambient temperature on ammonia emissions is mainly concentrated in the cold start stage. The influence of ambient temperature on ammonia emission is shown that the ammonia emissions of light-duty gasoline vehicles under ambient temperature conditions (14 and 23°C) are lower than those under low ambient temperature conditions (-7°C) and high ambient temperature conditions (35 and 40°C). The influence of TWC on ammonia emission is shown that ammonia is a by-product of the catalytic reduction reaction of conventional gas pollutants in the exhaust gas in the TWC. Under NEDC operating conditions and WLTC operating conditions, ammonia emissions after the catalyst are 45 times and 72 times that before the catalyst, respectively. In terms of ammonia emissions control strategy research, Pd/Rh combination can reduce NH formation more effectively than catalyst with a single Pd formula. Precise control of the engine's air-fuel ratio and combination with the optimized matched precious metal ratio TWC can effectively reduce ammonia emissions.
本研究通过实验室车辆台架试验，结合新欧洲驾驶循环（NEDC）和全球轻型车辆测试循环（WLTC）条件，获得了典型轻型汽油车的氨排放特性。环境温度对氨排放的影响主要集中在冷启动阶段。环境温度对氨排放的影响表明，在环境温度条件（14 和 23°C）下，轻型汽油车的氨排放量低于低温条件（-7°C）和高温条件（35 和 40°C）下的氨排放量。TWC 对氨排放的影响表明，氨是 TWC 中废气中常规气体污染物催化还原反应的副产物。在 NEDC 运行条件和 WLTC 运行条件下，催化剂后的氨排放量分别是催化剂前的 45 倍和 72 倍。在氨排放控制策略研究方面，Pd/Rh 组合比单一 Pd 配方的催化剂更能有效地减少 NH 的形成。精确控制发动机的空燃比并结合优化匹配的贵金属比例 TWC 可以有效地降低氨排放。
