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:
Jul. 18, 2000
Filed:
Aug. 27, 1997
Hisashi Kadowaki, Kariya, JP;
Denso Corporation, Kariya, JP;
Abstract
To control the air-fuel ratio of an internal combustion engine without variations and thus suppress deterioration of the exhaust gas, a canister for adsorbing evaporated fuel is connected to a fuel tank. A release passage connects the canister to an intake tube for an internal combustion engine. A purge duty cycle flow rate control valve is installed in this release passage. An ECU provides feedback control of the air-fuel ratio according to the oxygen concentration in exhaust gas, controls the idle speed via an ISC valve, and controls purge by the purge duty cycle vacuum switching valve. As the purge is carried out, evaporated gas is released from the canister and purged. The ECU makes a decision, in a non-purging mode, as to whether the amount of the purged gas reaches a purge limit that is a critical value tolerated at each instant of time. If the result is that the purge limit will be reached, the execution of the purge is inhibited. At this time, the purge limit is established according to a range of purged flow rates that might hinder the operation of the internal combustion engine.