Mass Air Flow Sensor PID:
Mass air flow meter
A mass air flow sensor is used to find out the mass of air entering a fuel-injected engine. The air mass information is
necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine. Air changes its density
as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the ambient
temperature and altitude, and this is an ideal application for a mass sensor.