Malfunction diagnosis apparatus for evaporated fuel purge system
US5954034A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 21, 1997 |
| Grant date | Sep 21, 1999 |
| Priority date | — |
| Expiry date | Oct 21, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M25/0809
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A malfunction diagnosis apparatus for an evaporated fuel purge system comprises an evaporated fuel processing unit, an air valve arranged between a canister and the atmosphere wherein, when the air valve is open, the canister communicates with the atmosphere and, when the air valve is closed, the canister is sealed from the atmosphere, means for setting, based on an engine operating condition, a time required to lower a pressure within a least a portion of the evaporated fuel processing unit to a predetermined negative value, means for detecting an atmospheric pressure and means for changing the introduction time of the negative pressure in accordance with the atmospheric pressure. Means are provided for determining whether a failure of the evaporated fuel processing unit has occurred based on a pressure change in the system during a predetermined testing time after the predetermined negative pressure has been introduced into the evaporated fuel processing unit by closing the air valve and opening for the changed introduction time the purge control valve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.