Oxygen concentration sensor element impedance detecting apparatus and method
US6468478B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 7, 1999 |
| Grant date | Oct 22, 2002 |
| Priority date | — |
| Expiry date | Jul 7, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/21
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An oxygen concentration sensor element impedance detecting apparatus and method that maintains sensor detection accuracy by shortening the sweeping time period of an element impedance detecting voltage. A sub-microcomputer performs at least two sweeping actions for switching an element application voltage Vo from a reference voltage to a sweeping voltage when it once detects the element impedance of the oxygen concentration sensor AFS, and A/D converts only one of the element application voltage Vo and an element current detecting voltage Vi during the sweep, to shorten the sweeping time period. A sensor drive circuit prevents the element application voltage Vo from being changed by the element current. Even if element application voltage Vo detection and element current detecting voltage Vi detection are performed by separate sweeps, detection results substantially identical to those of the case in which detection of those two voltages are performed during one sweep are obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.