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:
Aug. 21, 2001
Filed:
Aug. 06, 1999
Katsuhiko Kawamura, Kanagawa, JP;
Hideaki Kobayashi, Yokohama, JP;
Nissan Motor Co., Ltd., Yokohama, JP;
Abstract
In a leak diagnostic system of an evaporative emission control system for an internal combustion system, which utilizes a change in internal pressure in a predetermined fluid-flow passage ranging from a fuel tank via a canister to a purge control valve, in addition to a relative-pressure sensor for sensing the internal pressure, an atmospheric-pressure sensor is provided for sensing atmospheric pressure. The leak diagnostic system includes a control module which samples the pressure in the predetermined fluid-flow passage as a first fluid-flow passage pressure at a first sampling time when a predetermined decompressing operation is completed, and samples the pressure in the predetermined fluid-flow passage as a second fluid-flow passage pressure at a second sampling time when a predetermined time interval has been elapsed from the first sampling time. The leak diagnostic system makes a leak diagnosis by comparing the pressure differential between the first and second fluid-flow passage pressures with a predetermined leak criterion. The control module compensates for the pressure differential by the atmospheric-pressure change occurring for a time interval from the first sampling time to the second sampling time.