Automotive three filters, oil filters, fuel filters, and air filters. Among them, the oil filter acts on the engine lubrication system.

Introduction to Oil Filter
Oil filter, abbreviated as "machine filter", filters impurities in the lubrication system. Oil filters are divided into two types: split flow oil filters and full flow oil filters. The full flow filter is connected in series between the oil pump and the main oil passage to filter all the oil entering the system. A split flow filter, connected in parallel with the main oil passage, filters some of the oil.

Working principle of oil filter
When the engine is working, the oil is filtered through the filter element, and larger impurities in the oil are blocked. Clean lubricating oil enters the inner cavity of the filter element and flows into the main oil passage of the cylinder block through the threaded hole, completing the filter filtration of the oil.

In addition, some filters are also equipped with bypass valves and check valves.
The function of the bypass valve in the filter: When the filter element is blocked, the bypass valve will be opened, and the oil will enter the oil passage directly without filtering, ensuring that the engine is not damaged due to lack of oil lubrication.
The function of the check valve is to prevent oil from flowing back out of the filter, ensuring that there is oil lubrication in the oil passage during engine start-up, thus protecting the engine.

Disadvantages of conventional oil filters
1. The filter efficiency is low and can only remove some impurities in the engine oil
The existing oil filter has a single hole in the paper filter element. The smaller the micropores in the filter paper, the better the filtering effect of the filter, but the oil passing ability is poor. So on the same filter paper micropores, the filter element cannot effectively filter impurities, and long-term use of this filter can cause engine damage.

2. In some cases, the filter filtration function fails
To prevent damage to the engine due to a lack of lubricating oil, a bypass valve is installed at the bottom of the filter paper element. The oil circulating through the bypass valve cannot be filtered by the filter, and even the impurities that have been filtered out by the filter will be flushed back into the engine through the bypass valve, causing the filter to lose its filtering function and even cause secondary engine wear.