ilmamäärämittari

Ilmamäärämittari, also known as an air flow meter or mass air flow sensor (MAF sensor), is a device used in internal combustion engines to measure the amount of air entering the engine. This measurement is critical for the engine's electronic control unit (ECU) to determine the correct amount of fuel to inject. By accurately knowing the air mass, the ECU can optimize the air-fuel ratio, leading to better engine performance, fuel efficiency, and reduced emissions.

There are several types of air flow meters, with the hot-wire and hot-film types being the most common. The hot-wire MAF sensor uses a heated wire that is cooled by the incoming air. The amount of cooling is directly related to the mass of air flowing past it. The ECU measures the electrical current needed to keep the wire at a constant temperature, which in turn indicates the air mass. The hot-film MAF sensor works on a similar principle, but uses a heated film instead of a wire. Another type is the vortex or Karman vortex air flow meter, which measures the frequency of vortices shed by a bluff body placed in the air stream.

A malfunctioning ilmamäärämittari can cause a variety of engine problems, including rough idling, hesitation, poor acceleration, increased fuel consumption, and illumination of the check engine light. If a MAF sensor is suspected to be faulty, it is typically replaced. Regular maintenance and cleaning of the MAF sensor can help prolong its life and ensure accurate readings.