Car Engine valve's

HungryJoey

Can somebody please explain to me exactly what Valves are in car engines.. I know roughly what they are but what do they do ? And how does how many of them you have affect performance of your car? I have googled it but havn't found much exactly on valves them selves. Good description of a car engine on http://howstuffworks.com But nothing specific on Valves

Cheers,
Hj

dahamsta

You'll get a better idea of what a valve does by looking at a generic description in a dictionary, but in terms of engines the task of a(n inlet) valve is to let fuel into a cylinder and nothing back out. So the cam pushes the valve open, fuel goes in, and then the cam closes the valve to prevent the fuel (and exhaust) getting back into the inlet port. The exhaust (outlet) valve is much the same, except the cam opens the valve to let the exhaust out, and closes to prevent it getting back into the cylinder.

Multivalve engines "breath" better because you can have wider openings - and thus get more fuel into, and exhaust out of, the engine - with the same amount of lift from the cam. There's a fairly good descriptions of camshafts and valvetrains here.

If you want to see just how complex an engine can get, it's worth checking out the Veyron on the Bugatti website*. 16 cylinders in a W configuration, 4 valves per cylinder for a total of 64 on 4 camshafts, with 4 turbos thrown in for a power output of 1001bhp from 8 litres. Say what you like about the car, but that's bloody impressive engineering.

adam

* Models > Veyron > Engineering > Engine. You'll need Flash, and a broadband connection would be handy.

HungryJoey

Ok thanks Dude...

Few more thing's. Say Your Standard 16V 4 Cylinder Engine... I presume its Valves then per Cylinder ... What are 4 valve's for in 1 cylinder?

bp_me

Two inlet, two outlet.