What is a VAF Meter?

A VAF meter, also known as a Volume Air Flow meter, is an instrument used in automotive engineering to measure the volume of air flowing into an internal combustion engine. This measurement is crucial for the engine control unit (ECU) to accurately calculate the appropriate fuel injection and air-fuel mixture required for combustion.

VAF meters can come in various forms, but one common type is the hot wire or hot film VAF meter. In this design, a heated wire or film is placed in the path of the incoming air. As air flows over the wire or film, it cools it down, and the amount of cooling is proportional to the volume of air passing through. This change in temperature is then converted into an electrical signal, which the ECU uses to determine the air volume and adjust fuel injection accordingly.

Other types of VAF meters include vane meters, Karman vortex meters, and differential pressure-based meters. Each type has its own method of measuring airflow but serves the same fundamental purpose of providing input to the engine control system for efficient combustion.