Patent ID: 6171556
Filing Date: 2001-01-09
Classification: B01D,F01N,Y02T

Abstract:
An exhaust gas purifying apparatus for converting noxious components such as hydrocarbons and other pollutants from an engine exhaust gas into innocuous products, the apparatus comprising:a flow path for conveying engine exhaust gases containing hydrocarbons and other pollutants from an engine and comprising;a first catalyst zone in the flow path and downstream of the engine comprising a first catalyst effective for the conversion of at least some of the other pollutants into innocuous substances,an adsorbent zone disposed in the flow path in gas flow communication with and downstream of the first catalyst zone and comprising an adsorbent, which comprises H Beta zeolite material havina a relative Bronsted acidity of less than 0.5, for adsorbing at least some hydrocarbons in the engine exhaust gas, at least during a cold-start period of engine operation, anda second catalyst zone disposed in gas flow communication with and downstream of the adsorbent zone and comprising a second catalyst for at least converting unburned hydrocarbons into innocuous substances; andheat exchange means disposed in a heat transfer relation between the first catalyst zone and the second catalyst zone for providing heat transfer by indirect heat exchange from the first catalyst zone to the second catalyst zone.