Positive pressure canister purge system integrity confirmation
US5146902A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 1991 |
| Grant date | Sep 15, 1992 |
| Priority date | — |
| Expiry date | Dec 2, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M25/0818
- 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 a pressure switch. 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. Failure to build to a predetermined pressure indicates a gross leak. Upon attainment of the predetermined pressure, the pump is shut off by the operation of the pressure switch from one state to another. The pressure switch has hysteresis so that if the pressure falls below the predetermined pressure by a certain amount during the predetermined duration of the test, the pressure switch returns to its one state thereby giving a signal denying the integrity. Integrity is confirmed by the pressure switch remaining in its another state during the test.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.