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. 19, 1987
Filed:
May. 02, 1985
Katsuhiro Ina, Okazaki, JP;
Yoshihisa Sato, Nagoya, JP;
Masumi Kinugawa, Okazaki, JP;
Atsushi Suzuki, Oobu, JP;
Katsunori Ito, Ama, JP;
Susumu Akiyama, Kariya, JP;
Tiaki Mizuno, Toyota, JP;
Toshitaka Yamada, Nagoya, JP;
Tomoaki Abe, Nagoya, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
An air flowrate measuring apparatus with a heat wire measures the flow rate of the air flowing through the intake pipe of an engine. The apparatus has a temperature sensitive element which has a specific temperature-resistance characteristic and is disposed in the intake pipe. Constant heating voltage is applied to this element in response to a start signal, thus heating the element. When the temperature of the element rises to a specified value, the application of the voltage is stopped. At the same time, a pulse signal whose width corresponds to the period of applying the voltage is generated. The signal is supplied to an interface circuit through a drive circuit driven by a reference voltage which has been also used to control the heating voltage. The interface circuit comprises two wave-shaping circuits. The first wave-shaping circuit has a filter means of a small integration time constant. The second wave-shaping circuit has a filter means whose integration time constant is large enough to remove noise from the input signal.