Method of operating a three-way catalyst for internal combustion engines
US4199938A · kind A · utility
19Cited by
4References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1977 |
| Grant date | Apr 29, 1980 |
| Priority date | — |
| Expiry date | Dec 22, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A method of operating a three-way catalyst which contains an oxygen storage material and which is mounted on the exhaust system of an internal combustion engine is disclosed. In order to operate the three-way catalyst effectively, the air-fuel ratio of the mixture supplied to the engine is set to be richer than the stoichiometric ratio, and secondary air is intermittently supplied by an air pump into the exhaust system upstream of the three-way catalyst, thereby to alternately vary the air-fuel ratio of the exhaust gases supplied to the three-way catalyst to become rich and lean with respect to the stoichiometric ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.