国六轻型汽油车氨排放特性研究

Research on Ammonia Emission Characteristics of China-VI Light-duty Gasoline Vehicles

选择9辆国六轻型汽油车测定在WLTC工况下的氨排放。结果表明:9辆国六轻型汽油车平均氨排放因子达2.90 mg/km,最高可达11.62 mg/km;氨排放主要集中于低速段与中速段,其中低温环境下(-10℃与0℃)的氨排放远高于常温环境(23℃),采用自然吸气方式的轻型汽油车的温度影响系数更高;在高温环境(40℃)热启动试验中,在高速段与超高速段,由于偏离理论空燃比,导致在持续加速过程中出现氨排放峰值;在低温环境下,混合动力车辆氨排放持续存在;而在常温环境下低速段行驶过程中,由于动力电池参与动力供应,发动机启停频繁,导致催化器温度较低,氨排放在低速段并不明显,主要集中于中速段与高速段。

The ammonia emissions of 9 China-VI light-duty gasoline vehicles were measured under WLTC condition.The results show that the average ammonia emission factor of 9 light-duty gasoline vehicles is 2.90 mg/km,while the highest is 11.62 mg/km.Ammonia emission is mainly concentrated at low speed and medium speed,and ammonia emission at low temperature(-10℃and 0℃)is much higher than that at normal temperature(23℃).The influence coefficient of temperature of light-duty gasoline vehicle with natural aspirated engine is higher.In the hot start test at high temperature(40℃),ammonia emission peak appears in the process of continuous acceleration due to deviation from theoretical air-fuel ratio in the high-speed and ultra-high-speed sections.Under low temperature environment,ammonia emission of hybrid power vehicle continues to exist.However,in the low-speed driving process under normal temperature environment,because the power battery participates in power supply and the engine starts and stops frequently,the temperature of catalytic converter is low,and ammonia emission is not obvious in the low-speed section,while the ammonia emission mainly concentrates in the medium-speed section and the high-speed section.