Heizungsanordnung für einen Katalysator

摘要

A heating device for a catalyst, designed to reduce reaction delay and to guarantee that the catalyst carries out all of its functions. Said device can be electrically heated independently from the engine in order to avoid heat loss in the start phase before reaching operating temperature. According to the invention, the device comprises a sandwich structure with a thin, temperature-stable, heat-conductive electrically insulated supporting layer (16) connected to the surface (12) of the outer shell of the catalyst or the surface (14) of the inner shell of the catalyst or the surface (13) of the support for the catalyst, and a thicker electrically conductive heating layer (22) deposited on the surface of the support in a solid, flowable or pastelike form and provided with electrodes(18). Said heating layer functions as a resistance heating and a heat accumulator and contains carbon, graphite particles and carbon fibres. It is also surrounded by a heat insulating layer (23) when viewed from outside. The heating device is employed in a catalyst, especially a regulated three-way catalyst fitted with a catalyst support, comprising a ceramic monolith or a metal wrapped body with a honeycomb structure, to detoxify exhaust gas from internal combustion engines.