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Power piston diameter

Posted: Fri Sep 14, 2012 3:33 pm
by rustybarrel
Force = pressure x area
So I was thinking if I increase area of power piston by increasing its diameter will I get more power out of my stirling engine? Swept volume can be kept constant by reducing the stroke? Any idea? I will probably require a bigger flywheel also. I am not interested in more rpm but in more power.
Please tell me if I am right.
thanks
rustybarrel

Re: Power piston diameter

Posted: Fri Sep 14, 2012 9:09 pm
by Jerry
Generally speaking, decreasing the stroke increases RPMs, while increasing the stroke increases available torque.

Rather than concentrate on force, think in terms of work, which takes into account time. The same amount of force applied for a shorter time (decreased stroke) equals less work. The same amount of force applied over a longer time equals more work. In this discussion, I'm pretty sure you can equate work to power.

Re: Power piston diameter

Posted: Sun Sep 16, 2012 2:48 am
by Ian S C
You won't get any more power, high revs, low torque, or low revs high torque, sort of 2+1=3 or 1+2=3, just that it is possible to design a motor with the revs required for the aplication you want without needing much in the way of gearing, thereby increasing efficiency. Ian S C

Re: Power piston diameter

Posted: Sun Sep 16, 2012 3:05 am
by vamoose
Yes I think your right in saying that, Force = pressure x area (plus also, time and mass should be in there somewhere too)
But I liked this comment from Geoff V …............
Geoff V wrote:Pressurisation, the power output is proportional to the rate at which an engine processes the working gas, large turbo jets are probably processing around a ton every second!
i think i've interpereted it in the right context..

It helped me look at the processing of the working gas from a different angle.

vamoose