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:
May. 10, 1994
Filed:
Aug. 04, 1993
Katsuhiko Kondo, Himeji, JP;
Kouichi Nishimoto, Himeji, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In an internal combustion engine equipped with an exhaust gas recirculation control system including an exhaust gas recirculation passage connected to an exhaust pipe and an intake pipe of the engine and an exhaust gas recirculation control valve disposed in the exhaust gas recirculation passage for selectively closing and opening the exhaust gas recirculation passage, a method and an apparatus for diagnosing the exhaust gas recirculation system as to occurrence of an abnormality on the basis of a change in pressure or air flow rate within the intake pipe which is brought about by actuation of the exhaust gas recirculation control valve. By actuating the exhaust gas recirculation control valve in a diagnosis enabling operation state of the engine, it is determined whether the change in the pressure or air flow rate reaches a preset value within a predetermined time. Occurrence of an abnormality in the exhaust gas recirculation system is decided unless the change reaches the preset value within the predetermined time.