A drum-type aftertreatment system equipped with a new type of circumferential variable flow exhaust mixer was developed.Taking the aftertreatment of a 3.0 L China Ⅵ diesel engine as an example. First

the structure of the exhaust mixer was designed

the models of flow

as well as urea injection

atomization and diffusion in the catalytic converter were established

the full-scale exhaust flow field simulation analysis was carried out

the velocity uniformity

NH3 concentration distribution and pressure drop loss of the mixer were studied

and feature sizes were optimized. The results show that the uniformity of NH3 can reach 0.996 with the pressure drop of less than 4.17 kPa at the rated condition. Then

the validation by bench test was conducted. The results show that the newly designed aftertreatment system has smaller resistance

NH3 uniformity at the rated condition is 0.98

the mixer without spoiler performs better at different space velocities and temperatures. Finally

the engine emissions testing was carried out

the WHTC and WHSC cycle emissions meet the requirements of China Ⅵ standards

confirming that the newly developed SCR system and mixer can be used in the China Ⅵ heavy-duty diesel engine for on-road vehicles.