What is a PCV valve in a car?

[VonBrooklyn]

PCV valve, which stands for Positive Crankcase Ventilation, is an active ventilation control system, functioning as a metering control valve installed between the engine crankcase ventilation system and the intake system. 1. Introduction: The PCV valve consists of a valve body, valve, valve cover, and spring, and is non-disassemblable. Its primary function is to direct gases from the crankcase into the intake manifold via the PCV valve, with a small amount of air entering the intake manifold directly from the air cleaner through the PCV valve. This prevents throttle icing, incomplete combustion, and emission deterioration, while also stopping blow-by gases from entering the atmosphere and preventing engine oil deterioration. 2. Working Principle: The PCV valve is controlled by vacuum, regulating the flow of oil fumes generated by the crankcase ventilation system into the intake system. The flow rate is higher when the engine operates at high speeds compared to low speeds. Additionally, in the event of engine backfire, the PCV valve should cut off ventilation to prevent crankcase explosions.