Diamante Wagon V6-2972cc 3.0L SOHC (1993)
Air Flow Meter/Sensor: Description and Operation
Volume Air Flow Sensor Operation
Purpose
Provides the ECM with precise volume of air entering the engine. The ECM uses this information in addition to several other signals, to calculate
basic fuel injection pulse width.
Operation
"Karman Vortex" type AFS, measures volume of air by measuring the effect of incoming air on ultrasonic sound waves travelling through the
sensor chamber.
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An ultrasonic emitter sends sound waves across the airflow sensor chamber, where they are detected by the receiver. The time it takes the
sound to reach the receiver without any air flow is the "Reference Time" (speed).
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As air enters the intake stream, it strikes the vortex generating column creating vortices that swirl clockwise and counterclockwise. The
vortices interrupt the sound waves causing them to speed up, and slow down alternately.
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The change in speed is detected by the receiver and converted into a square wave signal, which is sent to the ECM in the form of the intake air
volume signal.
