Method for determining small quantities of carbon monoxide and nitrogen oxides in gaseous mixtures

US5503000A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Gerhard Huth · Stuttgart, DE
• Anton Kling · Gerlingen, DE
• Detlef Baresel · Stuttgart, DE

Key dates

• Filing date: May 20, 1994
• Grant date: Apr 2, 1996
• Expiry date: May 20, 2014

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02A50/20
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to a method for determining small quantities of carbon monoxide and nitrogen oxides in gaseous mixtures containing oxygen with the aid of a sensor whose electrical resistance changes at a higher temperature with the carbon monoxide and nitrogen oxide concentrations. It makes use of the fact that, with suitable sensors, on the one hand the resistance-temperature curve of the one of the gases to be determined is clearly different from that of the reference mixture over a broad temperature range (gaseous mixture without the two gases to be determined) and, on the other hand, the resistance-temperature curves of the two gases to be determined approach one another in one part of this temperature range, or coincide, and maintain a clear distance from one another in another part of this temperature range.