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. 11, 2010
Filed:
Nov. 25, 2008
Shiro Yamaoka, Hitachi, JP;
Yoshihiro Sukegawa, Hitachi, JP;
Noboru Tokuyasu, Hitachinaka, JP;
Hiroaki Hoshika, Hitachiohmiya, JP;
Kaori Kashio, Sakura, JP;
Shiro Yamaoka, Hitachi, JP;
Yoshihiro Sukegawa, Hitachi, JP;
Noboru Tokuyasu, Hitachinaka, JP;
Hiroaki Hoshika, Hitachiohmiya, JP;
Kaori Kashio, Sakura, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An engine that re-circulates its exhaust gas suffers decreased accuracy in estimating an EGR rate real-time especially while the operating state of the engine is in a transitional state, which often results in torque fluctuations and deteriorated exhaust gas. A sensor for directly detecting an EGR flow rate is disposed in an EGR path. An EGR rate and in-cylinder oxygen concentration are calculated from the output value of that sensor. In addition, when this EGR rate calculation method is used, the calculation is properly switched between a steady operation state characterized by a low load and small rotational fluctuations and a transitional operating state including the acceleration and deceleration. This makes it possible to correctly estimate the EGR rate and the in-cylinder oxygen concentration under a wide range of engine operation conditions, and thereby to avoid the fluctuation of torque and the deterioration of exhaust gas.