Positive pressure canister purge system integrity confirmation
US5297529A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1993 |
| Grant date | Mar 29, 1994 |
| Priority date | — |
| Expiry date | Jan 27, 2013 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M2025/0845
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
The tank/canister volume's integrity against unacceptable leakage is either confirmed or denied by a diagnostic test performed by an on-board diagnostic system which includes an electrically operated air pump and tank-mounted analog pressure transducer. At the beginning of a test, the engine management computer closes the canister purge solenoid valve and operates the pump to begin pressurization of the tank/canister volume. The pumped air is introduced via the canister's atmospheric vent port so that the pressurizing air is entrained with fuel vapors previously collected in, but not yet purged from, the canister. Failure to build to a predetermined pressure within a predetermined time indicates a gross leak. Upon attainment of the predetermined pressure, the pump is shut off. If the pressure drops by more than a certain amount during the test, integrity is denied. If not, integrity is confirmed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.