Air Flow Meter/Sensor: Description and Operation

Mass Air Flow Sensor:

PURPOSE
The Mass Air Flow Sensor (MAFS) converts the incoming air flow to a voltage signal that is measured by the ECCS Control Module (ECM).

OPERATION
The Mass Air Flow Sensor measures the intake air flow rate by taking a part of the entire flow. Measurements are made in such a manner that the ECM receives electrical output signals varied by the amount of heat emitting from the hot wire placed in the stream of the intake air.
When intake air flows into the intake manifold through a route around the hot wire, the heat generated from the hot wire is taken away by the air. The amount of heat depends on the air flow. On the other hand, the temperature of the hot wire is automatically controlled to a certain number of degrees.
Therefore, it is necessary to supply the hot wire with more electric current in order to maintain the temperature of the hot wire. The ECM knows the air flow by means of the electric change.