Purge monitor/switch rationality diagnostics
US6327901A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1999 |
| Grant date | Dec 11, 2001 |
| Priority date | — |
| Expiry date | Aug 30, 2019 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M25/0809
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A method is provided for determining the rationality of a device for monitoring the pressure within an evaporative emission control system of an automotive vehicle. The method includes opening a valve of the evaporative emission control system and determining if a vacuum switch of the evaporative emission control system opened. If the vacuum switch opened, a code is set indicating that the vacuum switch passed an opening test. If the vacuum switch did not open, the method determines if a fail timer is greater than a first fail threshold value. The first fail threshold value corresponds to an amount of time within which a properly functioning vacuum switch should open after said valve is opened. If the fail timer is greater than the fail threshold value, the method sets a code indicating that the vacuum switch failed the opening test. If the fail timer is less than or equal to the first fail threshold value, the method increments the fail timer. If the vacuum switch passed the opening test, the method closes the valve of the evaporative emission control system and applies a vacuum thereto. The method then determines if the vacuum switch closed due to the vacuum. If the vacuum switch…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.