Air-fuel ratio control system for internal combustion engines
US5682866A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1996 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Aug 30, 2016 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1456
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An air-fuel ratio control system for an internal combustion engine has an air-fuel ratio sensor arranged in the exhaust system of the engine, for detecting the air-fuel ratio of exhaust gases emitted from the engine, and various engine operating parameter sensors for detecting operating conditions of the engine. An ECU controls the air-fuel ratio of an air-fuel mixture to be supplied to the engine to a desired air-fuel ratio in a feedback manner responsive to an output from the air-fuel ratio sensor. A first learned value for correcting the desired air-fuel ratio is calculated based on the feedback control when the engine is detected to be in a first predetermined operating condition, and a second learned value for correcting the desired air-fuel ratio when the engine is detected to be in a second predetermined engine operating condition. The air-fuel ratio of the air-fuel mixture is controlled to a value leaner than a stoichiometric value, by using the first learned value. The first learned value is learned again when the difference between the first and the second learned values is larger than a predetermined re-learning-determining threshold value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.