The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 14, 1999
Filed:
Jan. 04, 1995
John K Hochmuth, Bridgewater, NJ (US);
Engelhard Corporation, Iselin, NJ (US);
Abstract
An exhaust gas treatment method for an exhaust system that includes a hydrocarbon trap (16) disposed upstream of a downstream catalyst zone comprising a catalyst effective at least for the oxidation of unburned hydrocarbons, in which air is added to the exhaust gas stream in an amount that provides a stoichiometric air/fuel balance in the exhaust gas entering the downstream catalyst zone. The air may be added at any point upstream of the downstream catalyst zone, but optimum results are obtained when air is added between the trap (16) and the downstream catalyst zone. The addition of air can be controlled by the output of a sensor (26) that measures the air/fuel ratio of the exhaust gas, disposed downstream of the trap (16), or by the output of a thermocouple (18) disposed upstream of the trap.