The working principle of the crankcase ventilation filter
Crankcase Ventilation filters are usually used in combination with PCV (Positive Crankcase Ventilation, crankcase forced ventilation) systems. The working principle of the PCV system is as follows:

Fresh air introduction: Fresh air is introduced into the crankcase from behind the air filter and mixes with the gas inside the crankcase.
Oil-gas separation: The mixed gas passes through the oil-gas separator. The separated engine oil is returned to the crankcase, while the gas continues to pass through the PCV valve.
Exhaust gas re-combustion: The gas enters the intake pipe through the PCV valve and is drawn into the combustion chamber together with fresh air or a mixture for re-combustion.
The installation position of the crankcase ventilation filter
The installation position of the crankcase ventilation filter usually varies by model, but it is generally located below the engine, close to the oil pan or transmission. The specific location may need to be referred to the vehicle's maintenance manual. Ventilation ducts are usually connected to the intake passage and pass through the oil-gas separation device on the valve cover before entering the intake pipe for combustion.

Maintenance of crankcase ventilation filters
To ensure the normal operation of the crankcase ventilation filter, regular maintenance is required

Inspect the ventilation ducts: Regularly check if the ventilation ducts are blocked and if there is any loosening or air leakage at each joint.
Clean or replace the filter: If the ventilation filter is contaminated or clogged, it should be cleaned or replaced in a timely manner.
Check the PCV valve: The PCV valve is a key component in the ventilation system. It is necessary to check whether it is flexible and whether the seal is intact.
Keep the air filter clean: The cleanliness of the air filter directly affects the efficiency of the ventilation system, so it needs to be cleaned or replaced regularly.