| An air filters remove solid particulates such as dust, | | | | that encounter high dust levels. |
| pollen, mold, and bacteria from air. Air filters are used | | | | Cotton |
| in applications where air quality is important, such as in | | | | Oiled cotton gauze is employed in a small number of |
| internal combustion engines, gas compressors, diving | | | | aftermarket automotive air filters marketed as |
| air compressors, gas turbines and others. The air | | | | high-performance items. In the past, cotton gauze |
| intakes of internal combustion engines and | | | | saw limited use in original-equipment automotive air |
| compressors tend to use either paper, foam, or | | | | filters. |
| cotton media. | | | | Oil Bath |
| Automotive cabin air filters | | | | An oil bath air cleaner is a round base bowl containing |
| The cabin filters are a pleated-paper filter that is | | | | a pool of oil, and a round insert which is filled with |
| located in the outside-air intake for the vehicle's | | | | fibre, mesh, foam, or another coarse filter media. |
| passenger compartment. Some filters are rectangular. | | | | When the cleaner is assembled, the media-containing |
| Others are shaped to fit the available space of the | | | | body of the insert sits a short distance above the |
| vehicles' outside-air intake. This filter is often | | | | surface of the oil pool. The rim of the insert overlaps |
| overlooked by owners. Clogged or dirty cabin air | | | | the rim of the base bowl. This arrangement forms a |
| filters can reduce airflow from the cabin vents, as | | | | labyrinthine path through which the air must travel in |
| well as introduce allergens into the cabin air. | | | | a series of U-turns: up through the gap between the |
| Internal combustion air filters | | | | rims of the insert and the base bowl, down through |
| The air filter prevents abrasive like dirt from entering | | | | the gap between the outer wall of the insert and the |
| the engine's cylinders that would cause engine wear | | | | inner wall of the base bowl, and up through the filter |
| and oil contamination. Most fuel injected cars use a | | | | media in the body of the insert. This U-turn takes the |
| pleated paper filter that looks like a flat panel. This | | | | air at high velocity across the surface of the oil pool. |
| filter is placed inside a plastic box connected to the | | | | Larger and heavier dust and dirt particles in the air |
| throttle body between the intake tube. Older vehicles | | | | cannot make the turn due to their inertia, so they fall |
| use carburetors or throttle body fuel injection | | | | into the oil and settle to the bottom of the base |
| sometimes use a round air filter, usually a few inches | | | | bowl. Lighter and smaller particles are trapped by the |
| high and between 6 and 16 inches round. It is usually | | | | filtration barrier in the insert, which is wetted by oil |
| located directly over the carburetor or throttle body | | | | drops aspirated by normal airflow. |
| and secured with a metal or plastic lid. | | | | Oil bath air cleaners were very widely used in |
| Paper | | | | automotive and small-engine applications until the |
| Pleated paper filters are the preferred choice for | | | | widespread industry adoption of the paper filter in |
| automobile engine air filters, because they are | | | | the early 1960s. Such cleaners are still used in |
| efficient, easy to service, and inexpensive. The | | | | off-road equipment where very high levels of dust |
| "paper" , as the filter media are considerably different | | | | are encountered, for oil bath air cleaners can |
| from other papers. | | | | sequester a great deal of dirt relative to their overall |
| Foam | | | | size, without loss of filtration efficacy or airflow. |
| Oil-wetted foam filters are used in some replacement | | | | However, the liquid oil makes cleaning and servicing |
| air filters. Foam was used in air cleaners on small | | | | such air cleaners messy and inconvenient, they must |
| engines and other power equipment, but cars paper | | | | be relatively large to avoid excessive restriction at |
| filter media has since replaced oil-wetted foam filters. | | | | high airflow rates, and they tend to increase exhaust |
| An oil-wetted foam filter can offer minimal airflow | | | | emissions of unburned hydrocarbons due to oil |
| restriction or high dirt capture, which makes this type | | | | aspiration when used on spark-ignition engines. |
| the choice in off-road vehicles and other motorsport | | | | References from Wikipedia, the free encyclopedia. |