Device for diagnosing oxygen sensor deterioration
US5927260A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1997 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Oct 3, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1456
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
The air/fuel ratio of an engine is feedback controlled based upon the output of an oxygen sensor. The control includes proportional control and also correction of a control variable for this proportional control according to the actual air/fuel ratio. The period of the output signal of the oxygen sensor during feedback control is measured, a decision value is set corresponding to change in the control variable, and deterioration of the oxygen sensor is determined by comparing the period of the output signal with the decision value. By doing this, change in the control variable is prevented from exerting any influence upon the period of the output signal of the oxygen sensor, and the accuracy of deterioration diagnosis for the oxygen sensor is enhanced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.