Guinness
|
| posted on 31/3/07 at 09:56 AM |
|
|
Help with Maths
How much air does my engine need, and how much comes out the exhaust?
I'm too thick to be confident of my working out of the maths! If my four cylinder engine is 1.1 litre (four stroke engine) then 1 cylinder is
0.275 litres.
So 1 revolution sees 0.275 litres expelled from 1 cylinder (plus expansion), 0.275 litres taken into 1 cylinder, 1 cylinder is in compression phase
and 1 cylinder is in the burn / expansion phase. So each revolution needs 0.275 litres of air and expels more than that.
So at max rpm 11,500 rpm I need 3,162.5 litres of air a minute? And my exhaust is going to be shifting somewhat more than that?
So 3,162.5 litres a minute is about 111 cubic feet per minute?
Second example, my V8 four stroke 4.4l engine, where each cylinder is 0.55 litre and max revs is 5,750rpm, works out at the same figure, 111 cubic
feet per minute.
Can someone wiser than me please check my maths?
Thanks
Mike
|
|
|
|
|
matt_claydon
|
| posted on 31/3/07 at 12:17 PM |
|
|
Those figures you give are for half a revolution (1 compression, 1 ignition, 1 intake and 1 exhaust). There are 2 intakes and 2 exhausts per
revolution, not one, so double those figures for a start!
[Edited on 31/3/07 by matt_claydon]
|
|
|
Simon
|
| posted on 31/3/07 at 01:09 PM |
|
|
This may, or may not be of assistance
http://www.grapeaperacing.com/GrapeApeRacing/tech/turbochargers.pdf
They have other pages too.
ATB
Simon
|
|
|
Angel Acevedo
|
| posted on 31/3/07 at 05:25 PM |
|
|
Volume of air= 1/2 Engine displacement X RPM X VE where
VE is a value ranging from something like 85% to above 100% for blown engines
Beware of what you wish.. for it may come true....
|
|
|
