Successive sections of ceramic exhaust pipe collecting soot - for burning off soot, operates electrically, electrostatically or magnetically to catalytically purify fumes

摘要

Exhaust fumes taken with soot particles e.g. from an IC engine (1) enter the first section (5) of an exhaust line made of ceramics or mixed material which is electrically chargeable or magnetisable, causing the soot particles to adhere. This section (5) of exhaust pipe carries external thermal insulation (3) and leads to an uninsulated second section (7), made in this case of ceramic material to which soot particles attach electrostatically. At least one of the surfaces (5, 7) is made of NOX catalyst and/or oxidn. catalyst. The first exhaust section (5) is electrically heatable in zones. Heat insulation between the two sections (5, 7) is by an intermediate sleeve (8) with lower electrical resistance than the first section. ADVANTAGE - Soot collect only in specified areas to a given depth, in an exhaust with low pressure loss. Exhaust cleaning is improved, esp. at idling speeds, with deposited particles burning off.