Failure determination method for O.sub.2 sensor
US5423203A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1993 |
| Grant date | Jun 13, 1995 |
| Priority date | — |
| Expiry date | Jul 16, 2013 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF01N2560/025
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A failure determination method for an O.sub.2 sensor is provided wherein the air-fuel ratio of a mixture is maintained at a value which produces a leaner or richer air-fuel ratio than a stoichiometric ratio by a predetermined value, for a predetermined time after an engine starts operating in an idle region, to thereby make the oxygen concentration of exhaust gas surrounding the O.sub.2 sensor uniform. Subsequently, the air-fuel ratio is forcibly subjected to an oscillatory change with a predetermined amplitude of .+-.10 to 15% of the stoichiometric ratio with respect to the stoichiometric ratio at a predetermined frequency of several Hz, to determine abnormality of the O.sub.2 sensor based on the change of the output voltage of the O.sub.2 sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.