System and method for monitoring a catalytic converter
US5953905A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 17, 1997 |
| Grant date | Sep 21, 1999 |
| Priority date | — |
| Expiry date | Jan 17, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A system and method for monitoring catalytic converter efficiency monitor the switch ratio of upstream and downstream exhaust gas oxygen sensors based on an acceptable temperature range of the catalytic converter mid-bed for each of a number of mass air flow ranges. The system and method also use vehicle speed and EGR to assure that the monitor samples data during repeatable, robust load-speed-temperature conditions. Switch data is stored in keep-alive memory to increase the confidence of the efficiency determination due to a larger data collection phase. A filter having a cycle based constant is used to filter a current switch ratio before incorporating it into an average switch ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.