What is a PCV valve in a car?

[OAdriana]

PCV is the abbreviation for Positive-Crankcase-Ventilation, which means the active ventilation control system for the crankcase (or oil pan). The PCV valve consists of a valve body, valve, valve cover, and spring, and cannot be disassembled. The main functions are as follows: It directs gases from the crankcase into the intake manifold through the PCV valve, with a small amount of air entering the intake manifold directly from the air filter via the PCV valve. This prevents issues such as throttle icing, incomplete combustion, and worsened emissions. It also prevents exhaust gases from entering the atmosphere and keeps the engine oil from deteriorating. The PCV valve is a metering control valve installed between the engine crankcase ventilation system and the intake system. It is controlled by vacuum to regulate the flow of oil fumes from the crankcase ventilation system into the intake system. The flow rate is higher at high engine speeds than at low speeds. Additionally, when an engine backfire occurs, the PCV valve should cut off ventilation to prevent crankcase explosions.