Is the purge control valve on rotaries the same thing as the pcv or positive crankcase ventilation on piston engine cars?

 

Basically yes, but it's a lot more complicated...
It's a vacuum triggered mechanical switch.


-Ted

 

A mechanical switch? I don't think so. Vacuum operated mechanical valve possibly. There is a diaphram inside under light spring tension which when vacuum is applied, raises the diaphram. Atleast thats how I remember it, after work I will look at it again to make sure.

The valve its self is not complicated, the "system" is more of the complicated part as the vacuum should only be applied at 2000 rpm or about 25% +/- throttle due to the where the port in the TB is placed. Its placed just before the throttle plates, when the plates open up the port is then placed in vacuum which then operates the PCV.

The operation of the purge control valve is similar to the EGR valve.