Air Filters

Internal combustion engine air filters:
The main application for air filters are combustion air to engines. The combustion air filter prevents abrasive particulate matter from entering the engine's cylinders, where it would cause mechanical wear and oil contamination.

Most vehicles and equipment use a pleated paper filter element in the form of a flat panel. This filter is usually placed inside a plastic box connected to the throttle body with duct work. Other equipment use a cylindrical air filter, usually between 100 millimetres (4 in) and 400 millimetres (16 in) in diameter. This is positioned above or beside the carburetor or throttle body, usually in a metal or plastic container which may incorporate ducting to provide cool and/or warm inlet air, and secured with a metal or plastic lid. The overall unit (filter and housing together) is called the air cleaner.

Air Filter

Air Filters by Equipment Brand

  AC Delco
  Allis Chalmers
  Arctic Cat
  Argo
  Ariens
  AYP / Electrolux
  Bad Boy
  Baja Motor Sports
  Black & Decker
  Bobcat
  Bolens
  Bombardier
  Bosch
  Bostitch
  Briggs & Stratton
  Campbell Hausfeld
  Can-Am
  Case
  Caterpillar
  Champion Power Equipment
  Clark
  Clinton
  Club Car
  Columbia
  Comet
  Craftsman
  Cub Cadet
  Cushman
  Desa
  Dewalt
  Ditch Witch
  Dixie Chopper
  Dolmar
  Dynamark
  Earthquake
  Echo
  Emglo
  Exmark
  EZ-Go
  Ferris
  Ford
  Fram
  GEHL
  Generac
  Genie
  Grasshopper
  Gravely
  Gutbrod
  Hayter
  Hilti
  Hitachi
  Homelite
  Honda
  Huskee
  Husqvarna
  Hustler
  ICS
  Ingersoll Rand
  Ironton
  Jacobsen
  Jenny
  JLG
  John Deere
  Jonsered
  K&N
  Kawasaki
  Kohler
  Kubota
  Landpride
  Lawn-Boy
  Lawn Chief
  LCT
  Lesco
  Lull
  Makita
  Mantis
  Maruyama
  Massey Ferguson
  Mastercut
   McCulloch
  Motorcraft
  MTD
  Multiquip
  New Holland
  Northstar
  Onan
  Oregon
  Partner
  Pioneer
  Polaris
  Porter Cable
  Poulan
  Poulan Pro
  Powerhorse
  PowerMate (Formerly Coleman)
  Raisman
  Red Max
  Remington
  Ryobi
  Sabo
  Sanborn
  Scag
  Sears Craftsman
  Shindaiwa
  Simplicity
  Ski-Doo
  Skyjack
  Snapper
  Solo
  Stiga
  Stihl
  Subaru / Robin
  Suzuki
  Tanaka
  Tecnamotor
  Tecumseh
  Tomahawk
  Toro
  Troy-Bilt
  Vermeer
  Wacker
  Walker
  Weed Eater
  White Outdoor
  Wisconsin
  Yamaha
  Yanmar
  Yard Machines
  Yard-Man

Air Filter Types

Paper
Pleated paper filter elements are the nearly exclusive choice for automobile engine air cleaners, because they are efficient, easy to service, and cost-effective. The "paper" term is somewhat misleading, as the filter media are considerably different from papers used for writing or packaging, etc. There is a persistent belief among tuners, fomented by advertising for aftermarket non-paper replacement filters, that paper filters flow poorly and thus restrict engine performance. In fact, as long as a pleated-paper filter is sized appropriately for the airflow volumes encountered in a particular application, such filters present only trivial restriction to flow until the filter has become significantly clogged with dirt. Construction equipment engines also use this. The reason is that the paper is bent in zig-zag shape, and the total area of the paper is very large, in the range of 50 times of the air opening.

Foam
Oil-wetted polyurethane foam elements are used in some aftermarket replacement automobile air filters. Foam was in the past widely used in air cleaners on small engines on lawnmowers and other power equipment, but automotive-type paper filter elements have largely supplanted oil-wetted foam in these applications. Foam filters are still commonly used on air compressors for air tools up to 5 horsepower (3.7 kW). Depending on the grade and thickness of foam employed, an oil-wetted foam filter element can offer minimal airflow restriction or very high dirt capacity, the latter property making foam filters a popular choice in off-road rallying and other motorsport applications where high levels of dust will be encountered. Due to the way dust is captured on foam filters, large amounts may be trapped without measurable change in airflow restriction.

Cotton
Oiled cotton gauze is employed in a growing number of aftermarket automotive air filters marketed as high-performance items. In the past, cotton gauze saw limited use in original-equipment automotive air filters. However, since the introduction of the Abarth SS versions, the Fiat subsidiary supplies cotton gauze air filters as OE filters.

Stainless steel
Stainless steel mesh is another example of medium which allow more air to pass through. Stainless steel mesh comes with different mesh counts, offering different filtration standards. In an extreme modified engine lacking in space for a cone based air filter, some will opt to install a simple stainless steel mesh over the turbo to ensure no particles enter the engine via the turbo.

Oil bath
An oil bath air cleaner consists of a sump containing a pool of oil, and an insert which is filled with fiber, mesh, foam, or another coarse filter media. The cleaner removes particles by adhering them to the oil-soaked filter media rather than traditional filtration, the openings in the filter media are much larger than the particles that are to be filtered. When the cleaner is assembled, the media-containing body of the insert sits a short distance above the surface of the oil pool. The rim of the insert overlaps the rim of the sump. This arrangement forms a labyrinthine path through which the air must travel in a series of U-turns: up through the gap between the rims of the insert and the sump, down through the gap between the outer wall of the insert and the inner wall of the sump, and up through the filter media in the body of the insert. This U-turn takes the air at high velocity across the surface of the oil pool. Larger and heavier dust and dirt particles in the air cannot make the turn due to their inertia, so they fall into the oil and settle to the bottom of the base bowl. Lighter and smaller particles stick to the filtration media in the insert, which is wetted by oil droplets aspirated there into by normal airflow. The constant aspiration of oil onto the filter media slowly carries most of the finer trapped particles downward and the oil drips back into the reservoir where the particles accumulate.

Oil bath air cleaners were very widely used in automotive and small engine applications until the widespread industry adoption of the paper filter in the early 1960s. Such cleaners are still used in off-road equipment where very high levels of dust are encountered, for oil bath air cleaners can sequester a great deal of dirt relative to their overall size without loss of filtration efficiency or airflow. However, the liquid oil makes cleaning and servicing such air cleaners messy and inconvenient, they must be relatively large to avoid excessive restriction at high airflow rates, and they tend to increase exhaust emissions of unburned hydrocarbons due to oil aspiration when used on spark-ignition engines.

Water bath
In the early 20th century (about 1900 to 1930), water bath air cleaners were used in some applications (cars, trucks, tractors, and portable and stationary engines). They worked on roughly the same principles as oil bath air cleaners. For example, the original Fordson tractor had a water bath air cleaner. By the 1940s, oil bath designs had displaced water bath designs because of better filtering performance.