Oil filter is a very important part of the automobile engine lubrication system, its main role is to filter the impurities in the oil to ensure the normal operation of the engine. Here is how the oil filter works:

1. Filter material: The inside of the oil filter is usually made of a special filter paper or filter material, which has a porous structure and can effectively intercept particles in the oil.
2. Oil flow: When the engine is running, the oil pump pulls the oil from the oil pan and passes through the oil filter. The filter is usually located between the oil pump and the main oil passage of the engine.
3. Impurity interception: When the oil passes through the filter material of the filter, impurities such as metal chips, dust, carbon particles, etc. are intercepted on the surface of the filter material.
4. Clean oil outflow: The filtered clean oil continues to flow to the various lubricating parts of the engine, providing lubrication, cooling, cleaning and anti-corrosion effects for the engine.
5. Bypass valve: There is usually a bypass valve on the oil filter. When the filter is blocked due to excessive impurities, the bypass valve will open, allowing the oil to bypass the filter and flow directly to the engine to prevent the engine from being damaged due to insufficient lubrication. However, the impurities in the oil will not be filtered at this time.
6. Replacement cycle: With the growth of use time, the filter will gradually accumulate more and more impurities, and the filtration efficiency will decrease. Therefore, the oil filter needs to be replaced according to the manufacturer's recommended cycle.

Although the working method of the oil filter is simple, it plays a vital role in ensuring the long-term stable operation of the engine. Regular replacement of oil and oil filter is one of the basic contents of car maintenance.