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. 25, 1997
Filed:
Sep. 10, 1996
Nissan Motor Co., Ltd., Kanagawa, JP;
Abstract
An apparatus for use with an internal combustion engine having a fuel vapor trap from which fuel vapor is purged into the engine through a purge passage having a purge control valve provided therein. The purge control valve is controlled to permit fuel vapor purge through the purge passage based on the existing engine operating conditions. An air/fuel ratio feedback control correction factor is calculated to correct the air/fuel ratio within a predetermined range based on the air/fuel ratio of the mixture supplied to the engine. A gain value is calculated based on a deviation between the air/fuel ratio feedback correction factor calculated with the fuel vapor purge and the air/fuel ratio feedback correction factor calculated without the fuel vapor purge and a purge rate of the fuel vapor flow rate to the intake air flow rate. The calculated gain values are stored in a memory in respective memory locations addressable by different fuel vapor amounts. The calculated gain value is stored in the memory in a memory location corresponding to the sensed fuel vapor amount to update a gain value stored previously in the memory location. A gain value is read from the memory location corresponding to the fuel vapor amount. The amount of fuel supplied to the engine is controlled according to a target value calculated based on the read gain value and the engine operating conditions.