Exhaust emission control system for internal combustion engine
US6216450A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1999 |
| Grant date | Apr 17, 2001 |
| Priority date | — |
| Expiry date | Mar 16, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An exhaust emission control system for an internal combustion engine diagnoses a NOx storage capacity of a NOx storage type three-way catalyst disposed in an exhaust passage. A control unit of the exhaust emission control system includes a calculating section which calculates a quantity of fuel to a cylinder to bring an air fuel ratio of air-fuel mixture closed to a target ratio and to output an injection signal to a fuel injector based on the calculated quantity of fuel, an executing section which executes a rich-spike treatment for temporally enriching the air-fuel ratio of air-fuel mixture supplied to the engine in a lean condition, and a diagnosing section which diagnoses a NOx storage capacity of said NOx storage type three-way catalyst on the basis of a peak value of the air-fuel ratio during the rich-spike treatment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.