The engine has air, oil, and fuel filters, which are responsible for the engine intake system, lubrication system, and combustion system intermediary filtration. below are the simple discription for the 3 filter element:
1: Air filter: clear the air,remove the dust enter into the engine, acts like a face mask,
protect the engine "heart" parts like cylinder,piston from abrasion.
2: Oil filter: mainly to filter oil impurities to ensure normal lubrication for engine and other engine parts.
3: Fuel filter: it's a kind of fuel filter which filter out fuel impurities, provide clean fuel for engine,
that protect engine and other important parts of the oil supply system.