Vehicle exhaust blocking

摘要

A unit 1 to be fitted in or at an end of an exhaust pipe contains a mechanically, electrically, pneumatically or hydraulically remotely-operable blocking device 5. The device 5 may be a butterfly valve, a resilient flexible tube (9, Fig. 3) which is flattened, a disc (13, Fig. 4) operable by a magnet (14) subject to electromagnets (16) adjacent the exhaust pipe (15) or an inflatable bag (19, Fig.5) in the unit.