Patent attributes
A measurement body is provided with a sub-outlet arranged between a U-turn portion of a bypass passage and a main outlet. The sub-outlet includes a first sub-outlet positioned on a path of air, which flows on the inside of the bypass passage, and a second sub-outlet positioned on a path of air, which flows on the outside of the bypass passage. The respective sub-outlets open in a sidewall surface of the measurement body along the thickness-wise direction. However, the first sub-outlet and the second sub-outlet are arranged in different positions with respect to the flow direction of measurement air. With this structure, a substantial length of the bypass passage can be adjusted in accordance with positions of the first sub-outlet and the second sub-outlet, so that compensation of intake pulsation is enhanced in accuracy. Thereby, measurement error caused by influences of intake pulsation can be reduced.