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:
Aug. 19, 1986
Filed:
May. 26, 1983
Tsuyoshi Tsuchida, Hiroshima, JP;
Yoshinobu Kido, Hiroshima, JP;
Mazda Motor Corporation, Hiroshima, JP;
Abstract
A Karman vortex generator is disposed in the air intake passage of an internal combustion engine. The frequency of the Karman vortex generated by the generator is detected by a Karman vortex frequency detector to measure the flow rate of intake air. The frequency of the Karman vortex is in proportion to the flow rate of intake air with a Strouhal number being the constant of proportionality thereof. However, when the flow rate or the flow velocity of intake air is within a certain range, the Strouhal number fluctuates and the proportionality between the Strouhal number and the flow rate of intake air is broken. This range is shifted when the kinematic viscosity of intake air changes. The kinematic viscosity of intake air depends upon the temperature thereof. Thus, the temperature of intake air is detected, and the output of the Karman vortex frequency detector is corrected when the air flow velocity represented by the output of the Karman vortex frequency detector is in such a range as to vary the Strouhal number taking into account the shift of such range due to the change of the kinematic viscosity of intake air.