Air Flow Sensor

Air Flow Sensor is a sensor used to measure air flow that sucked to the engine. Sensor will send information about air quantity to the ECU and ECU will compute data from sensor and send order to the injector to inject amount of fuel to the intake manifold for fuel air formation.
there are many type of air flow sensor such a Vane Type Air Flow Sensor


This sensor use a flap to measure air quantity sucked in to the engine. The greater air sucked the greater fuel will be injected to the manifold. This means, the angle of flap will be greater when air flow is high.


Hot Wire Air Flow Meter measure volume and density of air sucked to engine to calculate correct amount of fuel to be injected.The sensing element is a very fine wire of platinum alloy, just 0.7 millimeters (less than 0.003 inches) in diameter, strung across the interior of housing through which all the incoming air stream has to pass. The wire is heated by an electric current, but cooled by the passing air stream. An electrical circuit adjusts the current passing through the wire so as to maintain it at a temperature that is consistently 180° F above that of the entering air. Thus, if the air temperature is 80° F, the wire will be running at 260° F; if the air is at 30° F, the wire temperature will be at 210°. The current required to maintain this equilibrium is a measure of the mass of air passing the wire, and is used as the principal signal to the ECU as to air quantity.