Define and Air Filter:

[Zak33]

OK..down to you guys.....stick with just the subject item, don't get drawn into other terms.

What is an Air Filter (for a cars engine)? Whats it made of, why is it important and how does it work.
Ready.....steady....
Go

[TiG]

To help the engine breathe better? More cleaner air, remove particles?. = Better combustion.

THe filter i would guess is some sort of meshed fabric to stop dirt/soot/insects etc.

Thats about my level of understanding?
TiG

[Lowe]

Erks, I could go on forever here... But I won't. Short and sharp..

An air filter is there to stop contaminants getting into the engine through the induction side... and at the same time mute the noise down somewhat. They're made from paper usually, though sometimes are made from oiled cotton or foam (like induction kits).

[sdp]

The filter is made of cotton or perforated paper (in an old car it might be wire-mesh coated in oil). There are complicated equations which dictate the ideal filter size for a particular engine.

As to their purpose they're important because it filters out the rubbish in the air, which may otherwise get into the engine and cause premature wear and damage in the cylinders.

/I was reading up on air filters for minis a while ago this quite interesting as I was thinking that the cone-typ would give the best results on any engine.

[Zak33]

OK...good start...

so an Air Filter for a retail modern day car is normally PAPER....its often CORRUGATED so that you have a much larger surface area for air to filter through.

It does mute sound (induction roar) and it cleans the muck out of the air, so stoppingit getting into our precious beast's heart