Air Flow Meter/Sensor: Description and Operation

Air Flow Meter (Karman-Vortex):

A Karman-Vortex mass airflow meter is mounted in the air induction system near the air cleaner. The airflow meter measures intake air volume, and converts these readings into voltage signals by means of an ultrasonic sound transmitter mounted in the intake air stream. The transmitter sends sound waves across the airflow sensor at a specific reference time (speed). As air enters the intake stream, it strikes a vortex generating column and begins to swirl alternately from clockwise to counterclockwise. As the air flow passes between the transmitter and the receiver, the sound waves are interrupted, sending a square wave voltage signal to the ECU. These voltage signals are used by the ECU to determine injection duration and proper fuel delivery. The Airflow Sensor inputs the ECU through terminal KS.