Air Flow Meter
If you live in the United States of America, chances are you live in one of the many states which require annual emissions inspections for cars that are older than a certain number of years old. This measure was passed in order to keep our air unpolluted and our environment clean and green, and most people are happy (though they grumble about the small expense, anywhere from $20 to $40 in most places) to get their emissions checked annually and understand that this is one way to "go green."
Emissions inspections are also a good way to encourage auto makers to make more fuel efficient and cleaner running cars. This also encourages competition. With American automakers making admirable, clean and green cars, automakers from less developed countries are encouraged to follow their lead in order to help create a green, environmentally friendly world.
But what happens when you fail your emissions test? That can be a real pain in the rear. And people fail for many interesting reasons. I heard of one gentleman who failed because his gas cap did not fit tightly enough onto the car. Though gas caps not fitting tightly enough are one reason that a car might fail emissions, one big reason is that there is a problem with the car or truck's air flow meter.
An air flow meters, which is sometimes also known as an air consumption meter, is a device that is used to measure exactly how much air is flowing through a tube on a car. Contrary to some explanations, an air flow meter does not measure the volume of air passing through the car's tube. That belief is a misconception about the role of the air flow meter. No, the air flow meter is used to measure the speed of air flowing through the device. It does this by measuring the air flow through that tube or space within a defined segment of time.
The air flow meter came out of a subsection of physics dealing with mass flow meters. The air flow meter is simply and invention that allows for the applications of the principals of mass flow meter in order to measure the speed of the flow of air through a tube or device. Air flow meters, based on the science of mass flow meters, are not only used in cars and trucks, but in industrial machines and many other devices and pieces of equipment. When measuring air flow with an air flow meter, one will generally use kg/h (i.e. kilograms per hour.) Most physics is measured on the metric system due to its ease of measurement as compared to the standard system, which is still primarily used only in the United States and some other small countries such as Liberia. (Though, it can be argued that Liberia uses the metric system, only that they have not taken the time to officially adopt the practice.)
When dealing with using the air flow meter in your automobile, you may see it referred to as a mass air flow meter or a MAF. Don't be confused. This is simply the same thing, only used in such as way that it only refers to cars, trucks and other automobiles.
Air flow meters are used in cars in order to measure the quantity of air going to the engine. In fact, all modern, electronic diesel engines (such as those found in tractor trailer trucks, etc.) use an air flow meter in order to determine the quantity of air going to the engine. If the engine is not getting enough air, performance can drop off rapidly and that can eventually lead to a truck that overheats and simply will not run.