Air flow meter assembly

摘要

An air flow meter for detecting the air flow supplied to an internal combustion engine includes a hot-wire disposed in a by-pass air passage opening at its one end to a portion of an air passage upstream from a venturi portion formed in the air passage and at its other end in the venturi portion. The by-pass air passage is provided to lengthen a distance between the inlet opening of the by-pass passage and the hot-wire, to thereby settle the flow of air in the by-pass passage at least in the area around the hot-wire. The inlet opening of the by-pass air passage may open in a plane perpendicular to the axis of the venturi portion and within the area of upper projection of the venturi portion, to prevent carbon and oil particles from coming into the by-pass passage to thereby prevent the contamination of the hot-wire.