What is the function of the crankcase ventilation system?

The function of the crankcase ventilation system is to effectively manage the pressure within the crankcase and prevent oil leaks by recirculating gases back into the intake system. During normal engine operation, combustion gases can escape into the crankcase due to the effects of blow-by, which is when some of the combustion mixture bypasses the piston rings and enters the crankcase.

If these gases accumulate, they can create excessive pressure that can lead to oil leaks and gasket failures. The crankcase ventilation system, often comprising of components such as a positive crankcase ventilation (PCV) valve, allows these gases to be vented back into the intake manifold. This not only helps to maintain optimal crankcase pressure but also allows the gases to be re-burned in the combustion process, thus improving overall engine efficiency and reducing harmful emissions.

The other options do not accurately describe the primary function of the crankcase ventilation system. For example, increasing fuel pressure in the injectors is not related to crankcase ventilation; that function pertains to the fuel injection system. Similarly, cooling the engine oil involves the oil cooling system, and filtering impurities from the air that enters the engine is a role of the air intake and filtration system, not the crankcase ventilation system