Method and apparatus of on-board catalytic converter efficiency monitoring
US5272872A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1992 |
| Grant date | Dec 28, 1993 |
| Priority date | — |
| Expiry date | Nov 25, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/40
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
Apparatus and method are disclosed for monitoring catalytic converter efficiency in treating exhaust gas from an internal combustion engine having fuel control means for controlling the air to fuel ratio at which fuel is supplied to the engine in response to a fuel flow control signal. During a normal operation mode, the control signal means generates the fuel flow control signal based at least in part on output signals from first and second EGO sensors exposed to the exhaust gas upstream and downstream, respectively, of the catalytic converter. The normal operation mode is periodically interrupted by a test operation mode, preferably initiated during substantially steady state operation of the engine, during which the engine is controlled in response to the output signal from the first EGO sensor without the signal from the second EGO sensor. Air to fuel ratio perturbations about a mean value corresponding to stoichiometry are introduced, comprising an initial lean interval of air to fuel ratio higher than stoichiometry, typically for about 5 seconds, followed by a series of rich intervals alternating with lean intervals. An efficiency value for the catalytic converter correspondi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.