Method and apparatus for functional monitoring of a catalytic converter

US5560200A · kind A · utility

Assignee

• EMITEC Gesellschaft fuer Emissionstechnologie mbH · DE

Inventors

• Wolfgang Maus · Bensberg, DE
• Helmut Swars · Bensberg, DE
• Rolf Brück · Bensberg, DE

Key dates

• Filing date: Jun 7, 1995
• Grant date: Oct 1, 1996
• Expiry date: Jun 7, 2015

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Environmental technology
• WIPO sector: Chemistry

Abstract

A catalytic converter has a carrier structure and a catalytically active coating adhering to the carrier structure, and is disposed downstream of an internal combustion engine of a motor vehicle for cleaning exhaust gas. A method for functional monitoring of the catalytic converter includes determining a temperature of the catalytically active coating and/or of the structure of the catalytic converter at least at one location. A temperature of the exhaust gas is determined upstream of the at least one location of the catalytic converter. At least first derivatives over time of both temperature values are formed. A difference of the derivatives over time is formed. An instant after a start of the engine at which the difference changes its sign is ascertained. An apparatus for functional monitoring of the catalytic converter includes at least one measuring sensor for measuring a temperature of the carrier structure and/or of the catalytically active coating. At least one device determines an exhaust gas temperature. A differentiation circuit forms derivatives over time of the measured or determined temperatures. A subtraction circuit forms a difference between the two derivatives ove…