The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 13, 2001
Filed:
Aug. 30, 1999
Gary D. Dawson, Rochester, MI (US);
William B. Blomquist, Lake Orion, MI (US);
Chris J. Booms, Milford, MI (US);
DaimlerChrysler Corporation, Auburn Hills, MI (US);
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 session times of the automotive vehicle.