Air flow meter for internal-combustion engine.

摘要

The air flowing in through an air cleaner is passed through a main passage and sucked into an internal-combustion engine. A part of the air flowing through the main passage (16) flows in a by-pass passage (18). An air flow sensor (20) is provided in the by-pass passage. In this case, the length (1) of the bypass passage is substantially three or more times longer than that of a part (L) of the main passage corresponding thereto. Accordingly, even when the internal-combustion engine is operated with a throttle nearly totally open and the air in the main passage is pulsated, the average flow rate in the by-pass passage increases owing to the inertial lag effect obtained by lengthening the by-pass passage, so that it is possible to prevent the output of the flow sensor from undesirably lowering.