Not to nit pick..... but...
In the interest of accuracy, the "closed" in "closed loop" implies the presence of some type of feedback mechanism that is used to adjust the output control. For example, the O2 sensor in a closed loop fuel control system is used to provide feedback to the controller in order to adjust fuel delivery. The simple PCV systems that we are discussing here do not have any such feedback loop.
Just plain 'ol "closed" would probably be closer, but since the system draws in fresh air from the outside world is it really closed? Perhaps... At least in the context of this discussion - when comparing PCV to the older road draft tube systems.
Also, an often overlooked characteristic of the crankcase ventilation system is that under certain engine operating conditions, crankcase vapors are vented to atmosphere via the fresh air inlet. This usually occurs under certain speed/load conditions when manifold vacuum is relatively low, and the PCV valve/port is unable to mange the blow-by gasses being generated by the engine. Today's engines have less blow-by than their relatives of days gone by due to improvements in cylinder wall machining and piston ring fit - so this is probably not likely to be as big a deal as it once was.
It is very interesting that Cal. actually
required the retrofit of PCV on existing vehicles! Never underestimate the power of CARB, I guess... Was PCV operation somehow verified by inspectors, or was just a visual of the installation all that was required? Did the manufacturers produce these kits? Just curious as to how they were sized to each application, and if any carburetor modifications were required when the kit was installed.
The owners of these vehicles were probably PO'd at the time, but their engines probably thanked them for less oil contamination and increased longevity.
Best Regards.....
