Diagnostic apparatus for air-fuel ratio sensor
US5758632A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1996 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | Mar 29, 2016 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1456
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
The fuel ratio control system controls the supply of fuel to an internal combustion engine to achieve a target air-fuel ratio, based on the output of an air-fuel ratio sensor. The system may determine whether there is an abnormality in the air-fuel ratio sensor based on a comparison between a change of an air-fuel ratio correction coefficient, used to drive the air-fuel ratio to the target value, and a change of the target air-fuel ratio if the target air-fuel ratio has sharply changed. Alternatively, the diagnosis operation may be performed based on a comparison between a total air-fuel ratio correction amount and a change of the air-fuel ratio detected by the air-fuel ratio sensor, a phase difference calculation between peaks of the air-fuel ratio or the air-fuel ratio correction coefficent, or by accumulating the differences between the air-fuel ratio and the target air-fuel ratio, and the differences between the air-fuel ratio correction coefficient and a reference value, and comparing the accumulated values. In addition, the system may detect a sensor abnormality based on the deviation in phase of the air-fuel ratio from the air-fuel ratio correction coefficient. These system …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.