Aftertreatment mixing device with passive valve

The invention discloses an aftertreatment mixing device with a passive valve. The device is characterized in that an internal cavity is formed between a front shell and a rear shell, an air inlet is formed at an upper portion of the front shell, an air outlet is formed at a lower portion of the front shell, a flow guide plate is arranged between the front shell and the rear shell, a partition plate is arranged on one side of the flow guide plate and divides an internal cavity into an air inlet cavity and an air outlet cavity, an air inlet cavity communicates with the air inlet, an air outlet cavity communicates with the air outlet, an opening is formed in the partition plate, a passive valve is arranged on the opening, and the passive valve is closed when the airflow pressure is smaller than an initial torsion value and opened when the airflow pressure is larger than the initial torsion value. The device is provided with the passive valve, the passive valve is closed under the low-temperature and low-flow wor