Method for diagnosing an exhaust gas sensor and device for carrying out the method

US8650942B2 · kind B2 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Mathias Klenk · Petershöfe, DE
• Bernhard Kamp · Ludwigsburg, DE

Key dates

• Filing date: Jul 22, 2011
• Grant date: Feb 18, 2014
• Expiry date: Mar 19, 2032

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A method is described for diagnosing an exhaust gas sensor which is situated in the exhaust gas area of an internal combustion engine for the purpose of detecting at least one exhaust gas component, which is heated with the aid of a sensor heater and whose temperature is detected. A device for carrying out the method is also described. The exhaust gas sensor is heated to a diagnosis starting temperature which is higher than the exhaust gas temperature; the heat output of the sensor heater is reduced or the sensor heater is completely turned off at least to the extent that the sensor temperature is able to decrease; the decreasing sensor temperature is detected; a measure for the temperature drop in relation to time is ascertained; this measure is compared with a first temperature gradient threshold value; and an error signal is provided if the temperature drop is too slow and therefore the ascertained measure for the temperature drop in relation to time does not exceed the first temperature gradient threshold value.