Method and circuit arrangement for detecting the readiness for operation of an oxygen measurement probe

US4759328A · kind A · utility

Assignee

• VDO Adolf Schindling AG · DE

Inventors

• Thomas Blumel · Möhrendorf, DE
• Bernhard Lukas · Raunheim, DE
• Wolfgang Reisch · Bad Orb, DE
• Eberhard Mausner · Ludwigsburg, DE

Key dates

• Filing date: Oct 9, 1987
• Grant date: Jul 26, 1988
• Expiry date: Oct 9, 2007

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N33/007
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a method for detecting the readiness for operation of a oxygen measurement probe which is arranged in the exhaust duct of an internal combustion engine and serves together with a regulating device to regulate the preparation of the mixture for the internal combustion engine, the output voltage of the oxygen measurement probe is integrated with an integration time constant which is dependent on the internal resistance of the oxygen measurement probe. The rate of change of the output voltage is measured. Above a predetermined value of the rate of change, readiness for operation is noted. In a circuit arrangement for the carrying out of the method, there is connected to the output of the oxygen measurement probe the input of an integrator whose output is connected via an analog-to-digital converter to the input of a microcomputer. Also there can be fed to an integrator an initial value which lies in a central part of the operating range of the output voltage of the integrator.