Exhaust gas purifying system for internal combustion engines
US4216653A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1978 |
| Grant date | Aug 12, 1980 |
| Priority date | — |
| Expiry date | Jan 10, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An exhaust gas purifying system of the type utilizing a three-way catalyst containing an oxygen storage material includes an electronic control unit for controlling the amount of secondary air supplied to the exhaust system of an internal combustion engine. The electronic control unit receives a signal from an exhaust air-fuel ratio sensor indicative of an air-fuel ratio of the exhaust gases and provides a pulse signal to an electromagnetic valve disposed in the passage of the secondary air leading to the upstream of the three-way catalyst. The amount of secondary air supplied to the exhaust system is controlled such that the resultant exhaust gases having an exhaust air-fuel ratio greater than the stoichiometric ratio and those having an exhaust air-fuel ratio smaller than the stoichiometric ratio are alternately supplied to the three-way catalyst thereby to achieve the average exhaust air-fuel ratio to fall within the optimum purifying conditions of the three-way catalyst.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.