Stuck Open PCV valve

Dears,
Can someone tell me how a stuck open PCV valve can cause oil consumption?

Thank you

Both stuck open and stuck closed can cause high oil consumption.
Normally on a gasoline engine in conditions of high vacuum or when the throttle is closed the PCV valve is either fully closed or only slightly open this prevents excessive oil droplets bring drawn into the inlet.
Where the valve is stuck closed excessive pressure builds up in the crankcase, this has two effects: the first is it prevents the piston rings from effectively sealing as piston rings depend on the difference between compression pressure and crankcase pressure to hold the rings out against the cylinder wall, secondly the increased crankcase pressure increases oil leakage past seals and gaskets.

Thank you Adny.
May God repay you back for your kindness.

Have a great day

Back in the days of carbs in the 1960's and 1970's crankcase breathers vented into the air filter and before that directly into the atmosphere and no valve was required, usually just a mesh filter was use to try and recover some of oil mist droplets escaping.

As I mentioned earlier the piston rings seal depend on compression and combustion pressure exerted on the piston ring to force the ring into good contact with the bore. The gas pressure travels between the piston and bore pushing the piston ring downwards against the bottom of the piston ring groove and outwards against the bore.