Device for catalytic purification or decomposition of hot exhaust gases

摘要

The exhaust gases are passed through a two stage catalyst comprising a metal catalyst (10) which rapidly reaches the operating temperature after starting the engine and a ceramic catalyst (2) for normal operation. The metal catalyst is mounted on an inner support wall spaced from the outer wall of the catalyst by an air space to minimise thermal conduction. The inlet end of the catalyst housing is made of two concentric cone sections to form the insulating air space. The rear end of the inner wall is supported on a shaped insert ring (11) braced on the front lip of the ceramic catalyst support. The ceramic catalyst is slid axially into the housing and locates against a stop prior to sealing the housing.