Cylinder-by-cylinder air-fuel ratio-estimating system for internal combustion engines
US5806506A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1997 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Jul 25, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2200/0402
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A cylinder-by-cylinder air-fuel ratio-estimating system for an internal combustion engine includes an air-fuel ratio sensor arranged in the exhaust system of the engine, at a confluent portion of the exhaust system. The air-fuel ratio of a mixture supplied to each of the cylinders is estimated based the output from the air-fuel ratio sensor, by using an observer for observing the internal operative state of the exhaust system based on a model representative of the behavior of the exhaust system. The air-fuel ratio at the confluent portion is estimated by using a delay parameter representative of the response delay of the air-fuel ratio sensor, and the air-fuel ratio of the mixture supplied to each of the cylinders is estimated by using the estimated air-fuel ratio at the confluent portion. The estimated air-fuel ratio of the mixture supplied to each of the cylinders is subsequently used for estimating a value of the air-fuel ratio at the confluent portion of the exhaust system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.