2007-07-17 04:25:42 · 6 answers · asked by smashear 1 in Science & Mathematics ➔ Engineering
Cylinders are round for many reasons. Machining is easier typically than something like a square. Circular shapes provide tremendous strength. The explanation of this requires high level physics and calculus, but examples of it being applied is everywhere. Most tunnels are round, pipes for thing under pressure (water, gas, etc.), fuel tanks are round, and the high pressure gasses even have rounded caps or ends. The circular and spherical shape has no weak points. Flat sides and points of other shapes are week points. Also, with moving parts, you want no points. These points have a tendency of breaking off because of their weakness. A circle or oval has no points to break of and cause other problems.
2007-07-19 08:06:24 · answer #1 · answered by Ryan K 2 · 0⤊ 0⤋
If it was cubical (had a square cross section), then forces would not be distributed evenly inside the cylinder when combustion took place. Eventually metal fatigue would weaken the places inside the "square" cylinder where the pressures were the greatest and it would fail (develop a hole, warp, etc.).
With a circular cross section, the forces of combustion are more equalized around the perimiter of the circle. A circle is an inheritly stronger structure than a square, rectangle, triangle, or most other polygons.
It is also easier to machine a circular cylinder out of a block of metal, than a polygon with corners.
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2007-07-17 04:41:13 · answer #2 · answered by tlbs101 7 · 1⤊ 0⤋
The answer is simple ... manufacturability. Round (cylindrical) parts are by far the easiest to manufacture with a high degree of precision and reliability. Also, because of the pressures associated with internal combustion engines, cylinders provide a geometry with relatively low numbers of stress concentrations.
2007-07-17 06:13:46 · answer #3 · answered by Kevin S 2 · 1⤊ 0⤋
it's a long story unless you're into calculus but a (round) cylinder has the greatest volume per unit area of its base and its the change in volume of the fuel/air mixture that generates force on the piston.
2007-07-17 04:35:45 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Circular pistons distributed force evenly.
But actually, Honda made some motorbikes with OVAL pistons, rather than round pistons. e.g. NR750.
2007-07-17 04:34:37 · answer #5 · answered by dryheatdave 6 · 1⤊ 0⤋
it needs to reciprocate so whatever shape, i has to be long and uniform to make a seal. next you dont want the cross section to have any corners because any misalignment could cause them to seize up and gall. The only shape with no corners and no problems if it mis-aligns is a circle. So...a cylinder
2007-07-17 04:35:14 · answer #6 · answered by billgoats79 5 · 2⤊ 0⤋