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:
Jan. 11, 2005
Filed:
Jul. 21, 2003
Takahisa Koseki, Yokohama, JP;
Youichi Oshimi, Tokyo, JP;
Hatsuo Nagaishi, Yokohama, JP;
Nissan Motor Co., Ltd., Yokohama, JP;
Abstract
An internal exhaust gas recirculation amount estimation system calculates an in-cylinder temperature at an exhaust valve closure timing, an in-cylinder pressure at the exhaust valve closure timing, and a gas constant corresponding to a change in a composition of exhaust gas, based on an air-fuel mixture ratio. An exhaust valve closure timing in-cylinder residual gas amount is calculated based on at least the in-cylinder temperature, the in-cylinder pressure, and the gas constant. Also calculated is a valve overlap period blow-back gas amount, which is defined as a quantity of gas flow from one of intake and exhaust ports via a combustion chamber to the other port during a valve overlap period. An internal exhaust gas recirculation amount is calculated based on the exhaust valve closure timing in-cylinder residual gas amount and the valve overlap period blow-back gas amount.