How does an exhaust valve on a sulzer wallen engine work?

-how does an exhaust valve on a sulzer wallen engine work? I can not find a good explanation of how it works so i'm wondering if anyone knows?MAGIC!!!! THEM GOSH BLAM DARN WIZARDS ARE MIXING UP THE WHOLE WORLD WITH THIER FANCY SMANCY FLAYING MOCHINES
Not sure what kind of engine you're talking about. Read the manual, ask the chief, ask W盲rtsil盲...