Exhaust emission control system for internal combustion engine
US6839637B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 2002 |
| Grant date | Jan 4, 2005 |
| Priority date | — |
| Expiry date | Aug 30, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An exhaust emission control system for an internal combustion engine is disclosed. The system includes a NOx removing device provided in an exhaust system of the engine for removing NOx contained in exhaust gases, and an oxygen concentration sensor provided in the exhaust system. The air-fuel ratio of the air-fuel mixture to be supplied to the engine is changed from a value which is leaner than the stoichiometric ratio to a value which is richer than the stoichiometric ratio. It is determined whether or not a sulfur oxide concentration in the exhaust gases is high according to a transient characteristic of an oxygen concentration detected by the oxygen concentration sensor after the air-fuel ratio is changed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.