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:
Sep. 09, 1997
Filed:
Apr. 04, 1996
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
A trouble-detection apparatus for an EGR system provided with an EGR control valve in an EGR passage, capable of correctly detecting a position in the EGR passage at which the clogging has occurred. The trouble-detection apparatus is applied to the system having the EGR control valve controlled by a negative pressure in the EGR passage wherein a lift amount of the EGR control valve is controlled by a lift sensor in a feedback manner in accordance with the operating state of the engine. According to the trouble-detection apparatus, the amplitude of the lift amount detected by the lift sensor is obtained and the pulses in the exhaust-gas flow are calculated from the detected amplitude. When the amplitude of the pulses in the exhaust-gas flow does not reach a threshold value preset in accordance with the operating state of the internal combustion engine, it is determined that clogging as occurred in the EGR passage. In such a case, it is also possible to determine whether or not the clogging has occurred in the EGR passage by dividing the lift amount detected by the lift sensor into two subsystems, extracting solely a pulse component therefrom, calculating an amplitude of the extracted pulse component, and comparing the calculated amplitude with a threshold value.