Malfunction diagnostic apparatus for evaporated fuel purge system
US6679111B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 2002 |
| Grant date | Jan 20, 2004 |
| Priority date | — |
| Expiry date | May 30, 2022 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M25/0818
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
The present invention provides a malfunction diagnostic apparatus for an evaporated fuel purge system in an internal combustion engine, capable of detecting abnormalities such as looseness or clogging in the purge line between a purge valve and an engine intake passage. An electric pump 14 is turned on when a purge valve 5 is in a closed state and a selector valve 20 is in an open state. After the lapse of a given time period Tref, a load-current initial value I1 of the electric pump 14 is detected at the moment switching the selector valve 20 to a closed state. After the lapse of a given time period Tpump, the purge valve 5 is switched to an open state, and a load-current final value at the moment after the lapse of a given time period Tpurge. As in the curve A, when a load current final value I2A is equal to or less than the load current initial value I1, it is determined that the gaseous communication state in the purge line between the purge valve 5 and the intake passage is normal. On the other hand, as in the curves B and C, when load current final values I2B and I2C are greater than the load current initial value I1, it is determined that the gaseous communication state is a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.