piston engine questions

[downwind]

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]

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]

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]

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]

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]

@ barit 1

Many more happy returns!!!!!!!
And ofcourse ur right and the given ratio is just 5:1 and not 6:1.....