Method and system for maintaining efficiency of a three-way catalyst

US6634169B1 · kind B1 · utility

Assignee

• Johnson Matthey Public Limited Company · GB

Inventors

• Paul Joseph Andersen · Audubon, US
• Todd Howard Ballinger · Audubon, US
• David S. Lafyatis · Malvern, US
• Raj Rao Rajaram · Slough, GB
• Andrew Peter Walker · Royston, GB

Key dates

• Filing date: Jun 5, 2000
• Grant date: Oct 21, 2003
• Expiry date: Jun 5, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/12
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A catalyst system includes a three-way catalyst (TWC) mounted underfloor and an engine management system programmed to initiate an enrichment of the exhaust gases exiting the engine with at least one of CO and hydrocarbons and to add secondary air to the exhaust gases in the exhaust passage upstream of the TWC. This periodic enrichment and addition of secondary air causes catalytic oxidation of the at least one of CO and hydrocarbons over the TWC thereby raising the underfloor TWC temperature to at least 550° C., preferably higher, in order to reduce sulphur poisoning of the catalyst and maintain the desired catalytic activity.