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:
Nov. 26, 1996
Filed:
Oct. 03, 1995
Takahide Izutani, Susono, JP;
Hidemi Onaka, Susono, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
In the EGR system having an EGR control valve in an EGR passage, an orifice is provided on the exhaust side of the EGR control valve to define a negative pressure chamber between the EGR control valve and the orifice, and the pressure in the negative pressure chamber can be detected by a pressure-detector. When the operation state of the internal combustion engine is in a first operation zone wherein the amount of EGR is larger than a predetermined value, it is determined that clogging has occurred in the intake side EGR passage if the pressure value detected by the pressure-detector is smaller than a preset negative pressure value; while, it is determined that clogging has occurred in the exhaust side EGR passage if the pressure value detected by the pressure-detector is larger than the predetermined negative pressure value. An ON/OFF type pressure switch may be used as the pressure-detection means 17. As a result, it is possible to accurately detect the clogging position in the EGR passage without an increase in cost.