Air-fuel ratio detection system for internal combustion engine
US5540209A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 1994 |
| Grant date | Jul 30, 1996 |
| Priority date | — |
| Expiry date | Sep 13, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A system for detecting air-fuel ratio of an internal combustion engine by sampling outputs of an air-fuel ratio sensor installed at an exhaust system confluence point of said engine. A timing map is prepared to be retrieved by the engine speed and manifold absolute pressure to determine one among sampled data which are successively stored in buffers. It is selected such that as the engine speed decreases or the manifold absolute pressure increases, a datum sampled at earlier crank angular position is selected. At an engine equipped with a variable valve timing mechanism, a datum sampled at earlier crank angular position is selected in the valve timing is controlled for high engine speed provided that the engine speed and manifold absolute pressure is constant. The sampled data stored in the buffers may be transferred to another buffers at a predetermined crank angular position. The sampled data is corrected by an environmental conditions including atmospheric pressure, a mixture or sensor degradation. Each buffer may have a plurality of sampled data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.