Air filter prevents abrasive particulate matter from entering the engine's cylinders, where it would cause mechanical wear and oil contamination. Most fuel injected vehicles 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 an intake tube. Older vehicles that use carburetors or throttle body fuel injection typically use a cylindrical air filter, usually a few inches high and between 6 and 16 inches in diameter. This is positioned above 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 progress in filter constructing and application of modern filtration materials brings the level of contaminants filtration to the level of 99,9% for particles of even few micrometers size. Whereas the engines use a great amount of air during combustion process (average amount of 10m³ of air per 1 liter of fuel), filters with high filtering efficiency must also have low flow resistance and high contaminants absorptvity. Due to such properties, it is possible to extend the period between filter replacements.
Lubricate oil is the lifeblood of the engine. Engine with dirty oil can not last. Quality oil filter can protect your engine from all kinds of contaminants and make sure they all effectively trapped in filters. Regardless what kind of filter installed in ones car, the oil should be changed in accordance with the car manufacturer manual, so do oil filters. Oil filter can be significantly different in construction and principle of operation depending on engine type.
Serve a vital function in today's modern, tight-tolerance engine fuel systems. Unfiltered fuel may contain several kinds of contamination, for example paint chips and dirt that has been knocked into the tank while filling, or rust caused by moisture in a steel tank. If these substances are not removed before the fuel enters the system, they will cause rapid wear and failure of the fuel pump and injectors, due to the abrasive action of the particles on the high-precision components used in modern injection systems. Fuel filters also improve performance, as the fewer contaminants present in the fuel, the more efficiently it can be burnt. Diesel filter also has a function to separate water from fuel. It either holding water by double layer media or drain off the water from the bottom valve. Fuel filters need to be maintained at regular intervals. This is usually a case of simply disconnecting the filter from the fuel line and replacing it with a new one, although some specially designed filters can be cleaned and reused many times. If a filter is not replaced regularly it may become clogged with contaminants and cause a restriction in the fuel flow, causing an appreciable drop in engine performance as the engine struggles to draw enough fuel to continue running normally.