Air flow meter

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An air flow meter, also know as air consumption meter, is a device that measures how much air is flowing through a tube. It does not measure the volume of the air passing through the tube, it measures the amount of mass flowing through the device in a defined time segment. Thus air flow meters are simply an application of mass flow meters for a special medium.

The typical physical value is kg/h.

Contents

[edit] Types of air flow meters

[edit] Air flow meter in cars

An air flow meter is used in some cars to measure the quantity of air going to the engine. All modern electronically controlled Diesel engines use air flow meter as it is the only possible means of determining the air intake for them. The electronic control unit then calculates how much fuel is needed to inject into the intake manifold.

NOTE - the vane (flap) type air flow meters (Bosch L-Jetronic and early Motronic EFI systems) actually do measure air volume, whereas the later "hot wire" and "hot film" air flow meters measure mass flow.

The flap type meter includes a spring which returns the internal flap to the initial position. Sometimes if the spring is tensioned too tight it would make a restriction to the incoming air and it would cause the intake air speed to increase when not opened fully.

[edit] Symptoms

Air flow meters commonly fail in Vauxhall Corsa B's. This can be identified by jerkiness and extreme sluggishness. Often, when accelerating to about 50mph in third gear, the engine management light may come on and the car will slow suddenly.

[edit] Air flow meter for R&D of cars

In the development process of combustion engines with engine test stands an air flow meter/air flow measuring unit is used for measuring the continuous gravimetric air consumption of combustion engines.

[edit] See also

[edit] External links

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