I'm trying to understand how the crankcase ventilation system  works on my 1275 Mini engine. As I understand it a crankcase ventilation system pulls in air from the atmosphere, travels through the crankcase, through the PCV valve, and into the intake manifold all powered by engine vacuum. When I look at my car I see a hose from the rear of the crankcase, a hose from the front which join and than go into the PCV valve. Where does the fresh air enter this system? 

Thanks

Richard