Back to results
US 10,539,482 B2Granted
Oxygen sensor element blackening detection
AssigneeFord Global Technologies, LLC
InventorsMichael McQuillen, Gopichandra Surnilla, Richard E. Soltis, Daniel A. Makled, John Joseph Virga
Life of this patent
Estimating the term…
Abstract
The present description relates generally to methods and systems for detecting thermal aging and blackening in oxygen sensors. Thermal aging and blackening effects may be differentiated based on a monitored change in impedance in each of a pump cell and a Nernst cell of the oxygen sensor following application of an alternating voltage. In response to detection of thermal aging and/or blackening in the oxygen sensor corrective measures may be taken to ensure accurate oxygen estimation using the sensor.
Claims4
A method comprising:
- in a first mode of operation of an oxygen sensor:
- flowing exhaust gas from a combustion engine into a first cavity formed on one side by a zirconium oxide layer and on another side by a ceramic layer, the ceramic layer positioned between the first cavity and a second cavity containing a reference gas;
- applying a first voltage across the zirconium oxide layer to pump oxygen ions between the first cavity and the exhaust gas;
- and applying a second voltage across the ceramic layer, limiting the first voltage when the second voltage reaches a threshold;
- and
- in a second mode of operation of the oxygen sensor, detecting breakdown of a portion of the zirconium oxide layer to zirconium by comparing a change in impedance of the zirconium oxide layer to a change in impedance of the ceramic layer.
3 more elements
Dependencies are inferred from the claim text.