Air-fuel ratio control apparatus for internal combustion engines
US5528899A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 12, 1994 |
| Grant date | Jun 25, 1996 |
| Priority date | — |
| Expiry date | Dec 12, 2014 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/2454
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An air-fuel ratio control system for an internal combustion engine is provided. This system has an upstream air-fuel ratio sensor arranged upstream of a catalytic converter and a downstream air-fuel ratio sensor arranged downstream thereof, and learns a given feedback control parameter upon reversal of an air-fuel ratio between rich and lean sides based on the downstream air-fuel ratio sensor. The system also learns the given feedback control parameter when preselected conditions are met even if the air-fuel ratio is not reversed. Additionally, the system, when brought under open-loop control from feedback control, stores the given control parameter. Upon resumption of the feedback control, when the air-fuel ratio shows the same status, the stored given control parameter is used. Further, the system controls the air-fuel ratio based on the output from the downstream air-fuel ratio sensor when it moves out of a preselected range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.