摘要 |
<p>In an exhaust gas system comprising a hydrocarbon trap (28) and a downstream catalyst zone (30), a heat exchange catalyst member (10) is incorporated into the system to provide heat exchange between the exhaust gas and air that is pumped through the heat exchange catalyst member (10). The heated air is injected into the exhaust gas stream to facilitate the oxidation of hydrocarbons in the downstream catalyst zone. The heat exchange catalyst member (10) defines two separate flow paths therethrough, one of the flow paths containing a catalyst zone for the exhaust gas. In an alternative embodiement, the injected air is heated by a heat exchange trap (28') or by a separate heating element (62).</p> |