Air-fuel Ration Control

Sensor Review

ISSN: 0260-2288

Article publication date: 1 December 2004




Rigelsford, J. (2004), "Air-fuel Ration Control", Sensor Review, Vol. 24 No. 4.



Emerald Group Publishing Limited

Copyright © 2004, Emerald Group Publishing Limited

Air-fuel Ration Control

Air-fuel Ration Control

Applicant: Honda Giken Kogyo Kabushiki Kaisha, JapanPatent number: US6,739,122Publication date: 25 May 2004Title: Air-fuel ratio feedback control apparatus

Keywords: Patents, Control equipments, Aviation

The present invention provides an air-fuel ratio feedback control apparatus for an internal- combustion engine. The air-fuel ratio feedback control is performed when deterioration of a lean NOx catalyst is detected.

The apparatus includes: an air-fuel ratio detector that is disposed in an exhaust system of the engine, which detects the air-fuel ratio of the exhaust gas; a NOx purifier for purifying NOx contained in the exhaust gas during a lean operation; and feedback controller for making a feedback control upon an air-fuel ratio of air-fuel mixture to be supplied to the engine based on an output of the air-fuel ratio detector; and a diagnostic system that diagnoses the NOx purifier based on an output of an O2 sensor disposed downstream of the NOx purifier when the air-fuel ratio of the air-fuel mixture to be supplied to the engine has been changed from lean to rich. Additionally, the controlling apparatus comprises a three way catalyst disposed upstream of the NOx purifier, whereby the diagnostic system carries out the checking of the NOx purifier after the three way catalyst is recovered from sulphur poisoning.

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