Method for monitoring the efficiency of a catalytic converter for treating exhaust gases from an internal combustion engine
US5487269A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1994 |
| Grant date | Jan 30, 1996 |
| Priority date | — |
| Expiry date | Jun 22, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
An oxygen sensor, whose output signal switches between two levels, is arranged in the gas flow leaving the catalytic converter. During regulation at a stabilized speed, the injection time suitable for ensuring stoichiometry of the air/fuel mixture is determined. During a predetermined time interval a time variation of symmetric deviation, whose amplitude and shape is predetermined about a base injection time chosen from the determined injection time, is imposed on the injection time. The base injection time used during successive time intervals is modified progressively and in a monotonic manner so as to center the deviation of the injection time on that of the oxygen storage capacity of the catalytic converter. Catalyst efficiency is evaluated from an oscillation of this signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.