Air Flow Mass / Meter
For the modern ICE engine control unit (ECM / PCM) to control the amount of fuel delivered, one of the main input sensor signals required is the Air Flow or Air Mass entering the engine. An Air Flow Meter, AFM or Air Mass Meter, measures the air flow or air mass that is drawn into the intake of the engine. This measurement is transmitted as a frequency or a variable voltage to the ECM, ECU, or PCM so that it can calculate the correct amount of fuel to deliver via the injectors in relation to the air going into the engine. Other terms used for this sensor are: MAF Sensor, Mass Air Flow Sensor, or Karmen Vortex AFM.
Various designs have been used over the years by different manufacturers to measure the air delivery to the engine, including vane or flap, hotwire, hot film, membrane and karmen vortex type to name just a few. Early air flow meters had a swinging flap that would open in accordance with the amount of air flow into the engine, and these flaps would often be damaged during a backfire.
Injectronics can test, repair and remanufacture many brands of Air Flow Meter (AFM) and Air Mass Meters (AMM), including Bosch, Delco, Delphi, Hitachi, Kefico, Lucas, Mitsubishi, Nippon Denso, Siemens and VDO.
Injectronics tests and calibrates all air meters using an air flow analyser test bench, which flows air through the meter and precisely checks the output of AMM's and AFM's compared to learnt OEM specifications.