Process, use of the same and apparatus for lambda value detection

US5140535A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Lothar Raff · Waiblingen, DE
• Eberhard Schnaibel · Hemmingen, DE
• Michael Westerdorf · Asperg, DE

Key dates

• Filing date: Feb 20, 1990
• Grant date: Aug 18, 1992
• Expiry date: Feb 20, 2010

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02D41/1456
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a method for lambda value detection, the voltages of the loaded and the unloaded lambda sensor are detected and the internal resistance of the sensor is calculated from these values with the aid of the known value of the load resistance. The value of the internal resistance and the respective value of the voltage of the sensor in the unloaded state serve as input variables for a characteristic field, in which lambda values dependent on values of the internal resistance and of the voltage of the sensor in the unloaded state are stored. The method of the invention affords the advantage that lambda values can be measured very accurately even in the strongly temperature-dependent rich branch of a sensor, for example, of a sensor of the Nernst type. The values thus detected can be indicated by a measuring device or they can be used for exhaust gas control, for example in warming-up or at full load.