Failure diagnostic system of evaporated fuel processing system
US6738709B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 2002 |
| Grant date | May 18, 2004 |
| Priority date | — |
| Expiry date | Jun 27, 2022 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M25/0809
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A failure diagnostic system reduces the internal pressure of a fuel tank to a predetermined negative pressure, seals off the fuel tank from the air, and then determines whether an evaporated fuel processing system has failed or not by monitoring an increase in pressure in the fuel tank. In determination, the failure diagnostic system compares a detected pressure in the fuel tank with a reference value that is increased by a predetermined rate. The failure diagnostic system stops update of the detected pressure if the detected pressure becomes higher than the reference value, and resumes update of the detected pressure if the detected pressure becomes lower than the reference value. It is therefore possible to accurately determine whether the evaporated fuel processing system has failed or not even if the pressure in the fuel tank is rapidly increased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.