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:
Dec. 15, 2009
Filed:
Nov. 20, 2003
Hiroshi Nakano, Hitachi, JP;
Masamichi Yamada, Hitachinaka, JP;
Masahiro Matsumoto, Hitachi, JP;
Izumi Watanabe, Hitachinaka, JP;
Keiji Hanzawa, Mito, JP;
Keiichi Nakada, Munich, DE;
Hiroshi Nakano, Hitachi, JP;
Masamichi Yamada, Hitachinaka, JP;
Masahiro Matsumoto, Hitachi, JP;
Izumi Watanabe, Hitachinaka, JP;
Keiji Hanzawa, Mito, JP;
Keiichi Nakada, Munich, DE;
Hitachi, Ltd., Tokyo, JP;
Hitachi Car Engineering Co., Ltd., Hitachinaka-shi, JP;
Abstract
A thermal air flowmeter having excellent temperature characteristics and improved measurement accuracy. The thermal air flowmeter includes a temperature sensor disposed in a casing of the air flowmeter, a computing unit for correcting a flow rate detection voltage from a measuring element by using the temperature sensor, and a heating temperature control disposed in a temperature control circuit for performing temperature control of a heating resistor to vary a temperature rise of the heating resistor relative to an air temperature depending on the air temperature. Flow rate detection errors of the thermal air flowmeter caused by an overall temperature change and a temperature change on an intake passage wall surface can be corrected simultaneously and a thermal air flowmeter having superior measurement accuracy can be realized.