Method and apparatus for detecting abnormal state of evaporative emission-control system
US5203870A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1991 |
| Grant date | Apr 20, 1993 |
| Priority date | — |
| Expiry date | Jun 26, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M2025/0845
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
In an evaporative emission-control system having a canister for trapping a fuel-vapor evaporated from the fuel tank and a purge control valve for executing a purging, an amount of fuel-vapor trapped in the canister is measured while the engine is stopped or in an idle state. The trapped fuel-vapor is purged from the canister and mixed with an air-fuel mixture when the amount of fuel-vapor trapped in the canister is sufficient for diagnosis while the vehicle is running in a predetermined driving condition. In this purge operation, a concentration of a vapor-laden air from the canister is measured and the occurrence of an abnormal state of the evaporative emission-control system is determined when a change of the concentration of the vapor-laden air after the purging is less than a predetermined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.