Air filter: What does it do, and what are its types?

Air filter
Publié le Traduit avec l'aide de l'IA à partir de notre article original (source :

Almost every reasonable car owner does not forget about the regular maintenance of his car, including changing the air filter. However, some owners do not consider air filter replacement as something crucial and ignore it.

In this article, we'll look at what air filter does, what types of air filters there are, and when is the best time to replace them.

Table des matières

What does the air filter do?

The air filter is a device that captures solid particles such as dust, pollen, various insects, and similar things that could damage the combustion chambers, valves, and pistons.

It is usually placed in a plastic cover in the intake pipe of the combustion engine and thus prevents dirt from entering the combustion chamber.

Internal combustion engines most often use three types of air filters, namely:

  • paper air filter

  • cotton air filter

  • foam air filter

1. Paper air filter

Paper air filter

This type of filter is the most commonly used air filter for internal combustion engines. This is mainly because they are effective and very cheap. However, a paper air filter is only effective until its surface is covered with dust and other impurities. This is when the airflow is restricted, so less air enters the engine.

2. Foam air filter

Foam air filter

In the past, foam filters were mainly used in small engines and lawnmowers. Such a filter retains more dirt than a classic paper filter, while the airflow is only minimally restricted. This type of air filter is very popular with off-road and rally cars where there is a high level of dust.

A large amount of dirt can be captured on the foam filters without restricting the airflow. However, we can still find paper air filters on which a foam layer about 1 cm thick is glued, a combination of both filters.

3. Cotton air filter

Cotton air filter

Instead of a paper filter, a cotton filter can be used. This type of filter has greater air permeability, meaning that a larger amount of air gets into the engine while maintaining the same filtration as a classic paper filter. The disadvantage of the cotton filter is its price.

On the other hand, the advantage is a longer lifespan - it lasts for the entire car life and a slight performance increase. Sports and racing cars mainly use this type of air filter.

A clogged air filter has a bad effect on engine performance and consumption. The control unit adjusts the amount of injected fuel according to how much air gets into the intake.

If this filter is clogged, less air enters the combustion chamber, resulting in lower engine performance. This decrease in performance is often imperceptible, which is why many people forget about the air filter.


It should be noted that the price of the air filter is low, depending on the brand and the type of material from which the filter is made; therefore, its replacement should not be forgotten. The best option is to change the air filter along with an engine oil change, or at least every other engine oil change, depending on the dustiness of the environment in which you drive.