The air intake filter prevents abrasive particulate matter from entering the engines’ cylinders, where it can cause mechanical wear and oil contamination. Most fuel injected vehicles use a pleated paper filter element in the form of a flat panel. The filter is placed inside a plastic case and ducted through to the throttle body. However, older vehicles using carburetors or throttle body fuel injection typically use a cylindrical air filter. This is placed in a metal or plastic container with lid and also has ducts to provide cool or warm inlet air. The overall unit (filter & housing) is called the air cleaner.
Types of Air Filters –
- PAPER – Pleated paper filter elements are best choice for automobile engine air cleaners as these are effective, easy to service and cost-friendly. The misconception exists that paper filters allow poor air flow thus restricting engine performance. However, a suitably sized paper filter only restricts flow if it is clogged with impurities. The total area of the paper is large, approx.. 50 times the air opening.
- FOAM – Oil wetted polyurethane foam elements are used in some after-market replacement automobile air filters. Used in the past in small engines, lawnmowers and power equipment, these have been much replaced by paper filter elements. However, foam filters are still used on air compressors for small engines. It enables very high dirt trap capacity without restricting airflow. Foam filters are popular in vehicles used in off-roading and motorsport applications.
- COTTON – While its filtration efficiency is low, the oiled cotton gauze is employed in a growing number of motorsport applications due to the high air flow offered by its nature.
- STAINLESS STEEL – The SS mesh is another medium allowing more air passage. Different mesh counts offer different filtration standards. In hi-end engines with minimum space, the steel mesh over the turbo ensures no particles enter via the turbo.