Failure diagnosis apparatus for evaporative fuel processing system
US7367326B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 2006 |
| Grant date | May 6, 2008 |
| Priority date | — |
| Expiry date | Oct 15, 2026 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M25/0809
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A failure diagnosis apparatus for diagnosing a failure of an evaporative fuel processing system. The system includes a fuel tank, a canister having adsorbent for adsorbing evaporative fuel generated in the fuel tank, an air passage connected to the canister for communicating the canister with the atmosphere, a first passage for connecting the canister and the fuel tank, a second passage for connecting the canister and an intake system of an internal combustion engine, and a purge control valve provided in the second passage. A pressure in the evaporative fuel processing system is detected. An opening of the purge control valve is controlled by changing a duty ratio of a drive signal which drives the purge control valve. First and second filterings of the detected pressure are performed. A second passing frequency band of the second filtering is narrower than a first passing frequency band of the first filtering. A flow rate abnormality of a purge gas flowing in the second passage is determined based on the filtered pressures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.