Failure diagnostic system of evaporated fuel processing system
US6651491B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 2002 |
| Grant date | Nov 25, 2003 |
| Priority date | — |
| Expiry date | May 24, 2022 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M25/0836
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
There is provided a failure diagnostic system of an evaporated fuel processing system, which comprises a first failure diagnostic device that shuts off an evaporated fuel purge passage connecting a fuel tank and an engine intake passage from the air and determines whether there is any leakage from a large hole by monitoring the degree of increase in pressure in the fuel tank in which engine intake negative pressure is introduced; and a second failure diagnostic device that reduces a pressure the fuel tank to a predetermined negative pressure and seals off the fuel tank from the air to carry out failure diagnosis as to whether there is any leakage from a small hole by monitoring the degree of increase in pressure in the fuel tank. An operating range of the second failure diagnostic device is set to substantially include an operating range of the first failure diagnostic device and to be extended from the operating range of the first failure diagnostic device to include a lower intake negative pressure range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.