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downwind
18th Feb 2009, 02:40
Dear all,
I have a question;
An engine has a compressio ratio of 5:1, if the total volume is 1500cc, the swept volume will be??
Oh and ps does anyone have a good load of pratice piston enigne exams for an upcoming exam psiton engines exams I have to sit?
Thank you.
barit1
18th Feb 2009, 03:26
The 5:1 says the total volume can be considered 1500cc, divided into 5 parts.
One piston stroke displaces four of those five parts.
So, one part is 1500/5 or 300cc. Four parts is thus 1200cc; this is the swept volume.
But it's been a while...
nick14
18th Feb 2009, 10:51
Is it not 6 parts with the 5:1??
My calculations make 1 part 250, multiplied by 5 to make 1250 swept volume.
It has been a long while for me too!
Nick
barit1
18th Feb 2009, 13:53
No - in the bottom dead center state, the volume is 1500cc.
At top dead center the volume is 1/5 of 1500, or 300cc.
(That's how compression ratio is defined, isn't it?)
So the swept volume is: 1500-300 = 1200
barit1 - The Birthday Boy :)
qiutong
18th Feb 2009, 14:15
Happy birthday Barit1!
I agree with you. Nick14, you have taken six total parts, five swept and one combustion chamber, and sqeezed them into the one (combustion chamber) thereby describing a 6:1 comp ratio. 5:1 equals five total into one. The one is part of the total.
Hakeem
18th Feb 2009, 17:25
Many more happy returns!!!!!!!
And ofcourse ur right and the given ratio is just 5:1 and not 6:1.....:ok: