Air-fuel ratio control system and method
US7200988B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 10, 2005 |
| Grant date | Apr 10, 2007 |
| Priority date | — |
| Expiry date | Aug 10, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An air-fuel ratio control system has an upstream catalyst, a downstream catalyst, a first sensor for detecting a first air-fuel ratio present upstream the upstream catalyst, a second sensor for detecting a second air-fuel ratio present between the catalysts and a third sensor for detecting a third air-fuel ratio present downstream the downstream catalyst. An ECU determines a target second air-fuel ratio based on the detected third air-fuel ratio, and a target first air-fuel ratio based on the target second air-fuel ratio and the detected second air-fuel ratio. The ECU feedback controls an air-fuel ratio of mixture based on the target first air-fuel ratio and the detected first air-fuel ratio. The target first air-fuel ratio is corrected based on the detected third air-fuel ratio so that a change in the target first air-fuel ratio becomes smaller in a predetermined range other than a normal range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.