Thermal air-flow sensor

摘要

A thermal type air flow sensor wherein a heat generating element is arranged in an intake system, and a time for obtaining an increase in a temperature of a predetermined value is detected, which time corresponds to an amount of the intake air. The values of the intake air amount are averaged through one full cycle. This time is measured repeatedly at predetermined intervals during one full cycle of the pulsation, and a variation rate is calculated for values of the intake air amount obtained at two consecutive timings by a ratio of the difference of these values from the sum of these values. The average values of the intake air amount is corrected in accordance with this variation rate, to thus obtain a precise intake air amount.