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:
Jun. 13, 1995
Filed:
Jun. 30, 1993
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
An air-fuel ratio control system for an internal combustion engine which includes an evaporative fuel purge system having a canister for temporarily storing fuel vapor, detects an air to fuel ratio in the exhaust gas from the engine. An air-fuel ratio controller controls the air-fuel ratio in exhaust gas from the engine by varying a fuel quantity supplied to the engine so that the air-fuel ratio approaches a predetermined target air-fuel ratio. The evaporated fuel is purged from the canister at a specific purging rate determined based on engine operating conditions. An air-fuel ratio-shift is controlled based on the derivation of an amount by which the air-fuel ratio has shifted from the target air-fuel ratio due to a cause independent of the purging operation. The first amount, which is relatively constant over time in comparison to a second amount of air-fuel ratio shift occurring as a result of the purging operation, is derived based on a first detected air-fuel ratio-shift amount when the purge system is purging at a first purging rate. The second air-fuel ratio-shift amount is detected when the purge system is purging at a second purging rate different from the first purging rate.