The oil filter paper is the core component of the oil filter. It is mainly used to filter impurities in the oil and protect the engine. Its specific functions are as follows:

#### Filtering Impurities
- **Mechanical Impurity Filtration**: During the operation of the engine, engine oil may mix with metal wear debris, dust, and carbon deposits formed from combustion. The oil filter paper can effectively intercept these impurities, preventing them from entering the lubrication system and reducing the wear of engine components.
- **Gum and Sediment Filtration**: Under high temperatures and oxidative conditions, engine oil will produce gum and sediment, which can clog the oil passages and affect the fluidity of the oil. The filter paper can filter out these harmful substances, maintaining the cleanliness and fluidity of the oil.

#### Protecting the Engine
- **Reducing Wear**: By filtering impurities, the oil filter paper reduces the wear of the engine's internal precision components (such as the crankshaft, connecting rods, camshafts, piston rings, etc.), thereby extending the engine's service life.
- **Maintaining Lubrication Performance**: Clean oil can better perform its lubrication function, reduce friction, lower power loss, and enhance the engine's working efficiency and performance.

#### Auxiliary Functions
- **Pressure Regulation**: Some oil filters are equipped with a bypass valve. When the filter paper gets clogged and causes excessive oil pressure, the bypass valve will open, allowing the unfiltered oil to directly enter the lubrication system to prevent the engine from being damaged due to lack of oil. The filter paper plays a role in triggering the opening of the bypass valve during this process.
- **Preventing Air Locks**: The filtering function of the filter paper helps prevent air from entering the oil system, avoiding the occurrence of air lock and ensuring the normal operation of the oil pump.

In conclusion, the oil filter paper plays a crucial role in the engine lubrication system. It can effectively filter out impurities in the oil, protect the engine, extend its service life, and ensure the normal operation of the vehicle.