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. 04, 1997
Filed:
May. 09, 1995
Kazuhiro Sato, Kanagawa Pref., JP;
Yutaka Kawamoto, Kanagawa Pref., JP;
Nissan Motor Co., Ltd., Kanagawa, JP;
Abstract
A method of purging a canister is disclosed, wherein purge ratio is variably controlled under predetermined condition when air fuel ratio closed loop or feedback control based on output of an oxygen sensor is effected. Accumulated amount of purge air (EVPCNT) is calculated. The purge rate is increased as EVPCNT increases. But, when EVPCNT exceeds a predetermined large value (N), the purge rate is fixed at a very small value, for example 1% since the fuel remainder in the canister is considered minimum. As purging process proceeds, i.e., as EVPCNT increases, the percentage of evaporated fuel within the purge air is subject to a drop. To compensate for this drop, the purge rate is increased to cause the purge air to increase in amount, thereby to keep a ratio of flow rate of evaporated fuel to flow rate of air constant.