Serious question (pardon my vocabulary)?

Question

what would happen to the power output of an engine if we took the engine cillinder, and without altering its radius, we doubled the piston's surface (thus increasing the piston surface-cillinder volume ratio) assume equal cillinder volume and same fuel and air imput & efficiency.

In other words, if the pressure applied to the piston was the same, but the surface was larger, what would happen to the engine's power?

I know the first example sounds stupid, and impossible but it's just an abstract thought that came to my mind.

Thanks in advance!

Answer 1

How could you increase the area without increasing the radius? You can't.

Making the surface rougher and thus increasing the area that way would not help.

edit: a mathematical analysis of an impossible question is no help, it's still not possible to increase the area as you stated the problem.

Answer 2

piston surface has absolutely nothing to do with engine performace.  So whats your point.

However, what you did was increase clearance and reduced compression ratio.  the lower the compression ration, the less efficient.

Answer 3

I assume you mean that you create some sort of shape on the face of the piston to double its surface area.  It really does depend on the radius of the cylinder. Imagine whatever shape you were considering had lots of arrows that represent force on it normal (perpendicular) to the surface.  Some arrows might be pointing sideways or slanted or even upside down.  lets say that the piston moves in the z direction, then we break up the arrows into their x y z components, and then the only component that would matter would be the z  because x and y would just be pushing sideways on the piston.  If you add up all the z components from all of our arrows and then compare that to the z component of arrows on a flat piston face you would see that they are equal. Its a bit hard to explain with out a picture, hope this helps.

Answer 4

We learn t a formula (in college)

Engine HP = PLAN/33,000

P = Pressure in lbs/sq. inch

L = Length of stroke, inches

A = Piston area in inches (pi R^2), perpendicular to stroke

N = RPM of engine

If A is doubled, engine Horse Power gets doubled