Air flow amount measuring apparatus having flow rectifier

• Main Authors: KOHNO, YASUSHI, KOYAMA, HIDEKI, TSUNEKAWA, MAKOTO, TAKIGUCHI, TOMOYUKI, NAGASAKA, RYO, KONDO, MINORU
• Format: Patent
• Language: English; French; German
• Published: 29.04.2009
• Subjects: MEASURING; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; METERING BY VOLUME; PHYSICS; TESTING

A throttle unit (20) formed in a part of an inlet-side bypass passage (17) which is rectangular in transverse cross section is formed on both side walls from a throttle start end (25) to a throttle terminal end (26) relative to an air flow direction. Support members (27, 28, 29, 30) are provided in a throttle outlet side space (21) of the throttle terminal end and at a position which is hidden behind a convex throttling surface as viewed from the inlet side of the throttle unit (20). As the flow of air in the inlet-side bypass passage (17) does not contact directly with the support members (27, 28, 29, 30), turbulence of air is less likely to occur. Thus, an air flow amount signal is produced in the rectified air flow. The variation in the output of a thermal sensing unit can be reduced, because the flow amount is detected under a condition where the turbulence of air is less likely to occur over a wide range from a small air flow amount area to a large air flow amount area.