For crankcase emission to work, leaked combustion gases, are combined with air.
Then, are returned to the intake manifold, for reburning, in the combustion chamber.
The positive crankcase ventilation valve, or (PCV) valve, is the device that makes all this happen.
So, the crankcase emission system, is fairly basic. And, does not have a lot of parts. They all have a (PCV) valve, an air inlet filter, and connecting hoses. The location of these parts, however, may vary from one engine model to another.
(PCV) Valve or positive crankcase ventilation valve
The most critical part of the system is the flow control valve, commonly referred to as the (PCV) valve. The purpose of the (PCV) valve is to meter; the flow of the vapor from the crankcase to the intake manifold. This is necessary in order to provide proper ventilation for the crankcase, while not upsetting the fuel/air mixture for combustion.
Crankcase Emission, How it Works
At idle, the manifold vacuum is high; which would draw in, a large quantity of crankcase gases, causing the engine to run too lean. So, the (PCV) valve closes, restricting the quantity of crankcase gases, entering the intake system.
When the engine is under load or operating at higher (RPM), there are, even more blow-by gases. Consequently, the intake manifold vacuum, is lower in these conditions. As a result, causing the (PCV) valve to open even wider, allowing more gases flowing to the intake system.
Crankcase Emission, Failure Signs
Finally, as the (PCV) valve starts going bad, the performance of your vehicle will get worse.
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