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 NOxcontained 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 NOxpurifier 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 NOxpurifier, whereby the diagnostic system carries out the checking of the NOxpurifier after the three way catalyst is recovered from sulphur poisoning.
