The requirements of automobile for oil filter are as follows:
　　A, filter out all b > 30 um particles, reduce into lubrication gap and cause of wear particles (< 3 um um - 30) c, oil flow in engine oil demand, at least longer than the life of the engine oil replacement cycle e d and filtration precision conform to protect the engine and reduce wear requirements f, large amount of ash, suitable for harsh environment g, can adapt to the high oil temperature and corrosive environment h, filter oil differential pressure is lower, the better, to ensure that the oil can pass smoothly
　　3. Complexity