Evaporative emission control for very small leak detection
US6314797A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1999 |
| Grant date | Nov 13, 2001 |
| Priority date | — |
| Expiry date | Aug 30, 2019 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/042
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A method is provided for detecting a very small leak in an evaporative emission control system of an automotive vehicle. The method includes sealing the evaporative emission control system at a key-off event and monitoring a vacuum switch coupled to the evaporative emission control system for a closing event due to a natural vacuum created in the evaporative emission control system as it cools. If the closing event is not detected, the method determines if a leak detection timer has exceeded a predetermined threshold value. If the timer has exceeded the predetermined threshold value, the method sets a fault code indicating that the very small leak has been detected. Preferably, the leak detection timer includes a first time value corresponding to an amount of time the automotive vehicle has been operating since a previous small leak detection test was conducted and a second time value corresponding to an amount of time the automotive vehicle has been inoperative since a previous small leak detection test was conducted. The first time value includes a series of individual trip times of the automotive vehicle while the second time value includes a series of individual inoperative ses…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.