Injector sealing structure for urea-based selective catalytic reduction system, has resin seal and expanded graphite seal arranged between inner circumferential surface of housing and external circumferential surface of injector

摘要

The structure has an injector (6) for injection of a reducing agent on ammonia base e.g. aqueous urea solution and ammonia gas, into an exhaust tube (12) of a combustion engine. An air cooling mechanism (24) for air cooling the injector is connected with the exhaust tube. The cooling mechanism has a housing (24a) in which the injector is arranged. A resin seal and an expanded graphite seal are arranged between an inner circumferential surface of the housing and an external circumferential surface of the injector. An independent claim is also included for an after-treatment exhaust gas system.