Auxiliary air flow control device

The invention discloses a secondary air flow control device which is arranged between an intake end and an exhaust end of an engine. The air flow control device comprises a device body. The inside of the device body is provided with an air chamber. An intake pipe which is communicated with the intake end, and an exhaust pipe which is communicated with the exhaust end are arranged on the device body. The intake pipe is communicated with the exhaust end by the air chamber. The inside of the air chamber is provided with a bearing seat and has at least one vent. The inside of device body or the bearing seat is pivoted with a moving part which has at least one choke and a shielding part which control the open area of the vent. The moving part is connected with a throttle lead wire which draws the moving piece to rotate and reset to allow the choke and the shielding part to control the open area of the vent to control secondary air flow precisely. The device allow NOX and CO to be reduced effectively in the presenc