Oxygen concentration detector under temperature control
US4543176A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1984 |
| Grant date | Sep 24, 1985 |
| Priority date | — |
| Expiry date | Mar 2, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/4065
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An oxygen concentration detector under a temperature control for an internal combustion engine. An oxygen sensor of a critical current type is held between a gas under test and a reference gas, in the vicinity of which a heater is located for heating up the oxygen sensor in a sensor activating temperature range. A first voltage is applied for a positive bias control to the oxygen sensor during a first period, and a second voltage is applied for a negative bias control thereto during a second period. Electric current flowing through the oxygen sensor is detected during the first period in order to detect the oxygen concentration in the gas under test. The current value is also detected during the second period in order to detect and maintain constant the internal electric resistance of the oxygen sensor by controlling the heater heating output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.