What does engine size actually mean?

TheMagicPirate

TheMagicPirate

TheMagicPirate

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When people refer to engine sizes 1.1l, 1.2l etc what do these numbers actually mean? (I know its 1.1, 1.2... litres)

Is it how much petrol the engine holds in its pistons? How much petrol is runs through per minute while ticking over? The actual size of the engine should you melt it down?!

I've never thought about it until now.
 
It's the total volume of air/fuel mix that an engine can draw in during one complete cycle (i.e. a full suck/squeeze/bang/blow for each cylinder) - effectively how much the engine inhales in total once each cylinder has fired :)

For example, taking mine as the subject (5.7 litre smallblock Chevy, 10.16cm bore, 8.84cm stroke, 8 cylinders):

Displacement = pi/4 * d^2 * stroke * cyl

pi = 3.142
pi/4 = .7853975
d = bore diamenter of a cylinder (10.16cm)
d^2 = d-squared
stroke = stroke of crankshaft (8.8392cm)
cyl = number of cylinders (8)

Therefore:

Displacement = .7853975 * 10.16^2 * 8.8392 * 8
= 5732.97cm^3
= ~5.7 litres
 
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