What Does 16v , 8v, 4v Means?

[hyndai]

Guys

What does this "Valve" thing means in engines? 16v, 8v & so on... what are the pros & cons of having each level of valvs?

[maithri]

Hi, Valves are like doors operated mechanically to allow the fuel air mix to enter the combustion chambers at the top of the cylinders and for the burnt gases(exhaust) to exit from the cylinders. Older engines had one inlet valve and one exhaust valve per cylinder. Most modern engines have more-two inlet and two exhaust valves per cylinder normally to make the entry and exhaust gases more efficient giving more power as well as more economy by burning almost all the fuel air mixture admitted to the cylinder. So 16v means 16 valves in the engine-4 per cylinder times 4 cylinders. 12v is normally on 3 cylinder engines,20v on 5 cylinder engines and 24v on six cylinder engines. There were a few models with 3 valves per cylinder 2 inlet and one exhaust to confuse the issue a bit.

Hope I havent baffeled you with science.

Mike.

[Dinu]

  hyndai said:

Guys

What does this "Valve" thing means in engines? 16v, 8v & so on... what are the pros & cons of having each level of valvs?

this article might be helpful - http://auto.howstuffworks.com/engine.htm

[hyndai]

  Dinu said:

this article might be helpful - http://auto.howstuffworks.com/engine.htm

thsnkss!! so, from what i understood, it has no downfalls, is it? does it affect fuel consumption? i mean can it burn more fuel, since more valves apparently means more fuel into burn chamber?

any way, thanks guys!

[gunat]

No Mate- every engine has valves, just a question of how many. Its not an accessory or add-on...you're stuck with whatever the car has.

[Silver]

  gunat said:

No Mate- every engine has valves, just a question of how many. Its not an accessory or add-on...you're stuck with whatever the car has.

Umm... not necessarily.

Just to confuse the 'valve' issue a bit more - Most car engines nowadays use engine designs which have the 'valves' to let in the mixture/let out exhaust..

BUT on two-stroke engines (yeah yeah, I know is not really relevant, but since the valves issuse arose...] there are no valves - its designed so that the movement of the piston controls the mixture coming in or exhaust going out...

Try this if you want more info - http://www.howstuffworks.com/two-stroke.htm

As for answering the opening question - typically the no. of valves go up with the no of cylinders.

ie.

The infamous Bugatti Veyron has a staggering 64 valves in its 8l engine.

The Mercedes CL600 (W140) got an engine with 48 valves (12 cyl - 4 each - 2 inlet/2 exhaust)

The Evolution (4G63) has 16 valves (4 cyl, 4 each - 2 inlet/2exhaust)

But to confuse it more... the Toyota's 4A-GE have 20 valves in its 4 cyl engine. (I think its 3 inlet/2 exhuast valves)

So you really can't say more the better or the other way around... its part on engine design...

Edited September 5, 2007 by Silver