US 9,810,561 B2
Flow rate measuring apparatus
Shinichiro Hidaka, Tokyo (JP); Yuji Ariyoshi, Tokyo (JP); and Masahiro Kawai, Tokyo (JP)
Assigned to Mitsubishi Electric Corporation, Chiyoda-ku, Tokyo (JP)
Filed by Mitsubishi Electric Corporation, Tokyo (JP)
Filed on Sep. 30, 2015, as Appl. No. 14/870,152.
Claims priority of application No. 2015-099743 (JP), filed on May 15, 2015.
Prior Publication US 2017/0023389 A1, Jan. 26, 2017
Int. Cl. G01F 5/00 (2006.01); G01F 1/69 (2006.01); G01F 1/696 (2006.01); F02D 41/18 (2006.01); F02M 35/10 (2006.01); G01F 1/684 (2006.01); G01F 1/698 (2006.01); F02D 41/28 (2006.01)
CPC G01F 1/69 (2013.01) [F02D 41/187 (2013.01); F02M 35/10386 (2013.01); G01F 1/6965 (2013.01); F02D 2041/281 (2013.01); F02D 2200/0414 (2013.01); G01F 1/684 (2013.01); G01F 1/6842 (2013.01); G01F 1/698 (2013.01); G01F 5/00 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A flow rate measuring apparatus that is placed in an intake passage of an internal combustion engine and measures the flow rate of intake air, comprising:
a flow rate detecting device placed in the intake passage;
a detection circuit for outputting an analog signal varying depending on the flow rate detected by the flow rate detecting device;
a conversion circuit for converting the analog signal to a digital signal;
a temperature detecting device for detecting the temperature of intake air; and
a correction circuit for performing a primary correction by giving a correction coefficient having a temperature coefficient to a temperature characteristic correction formula that is a linear function of the digital signal,
wherein the correction coefficient varies depending on the temperature coefficient that is set in any appropriate way and the temperature detected by the temperature detecting device, and
wherein a plurality of the correction coefficients are set depending on the flow rate of intake air by dividing a flow rate region of the intake air into a plurality of flow rate regions and separately setting a correction coefficient among the plurality of correction coefficients for each of the plurality of flow rate regions.