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Old 03-19-2011, 05:58 PM   #6
MagicRat
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Re: Help me for design calculations

Good post, jd,

What I was trying to get at was the engine configuration. A 14.4:1 compression ratio is virtually unusable in a 4 stroke configuration, which tells me the engine design is actually a 2-stroke.

One can apply the same math if one knows the height of the ports in the cylinder wall. The engine would only develop compression after the ports have been closed by the piston moving upwards.

For example, if the top of the port is half-way up the cylinder wall, the effective compression ratio would be cut in half, or 7.2:1.

Furthermore, the total compressible volume of the engine would also be cut in half, reducing the total fuel/air mixture available for combustion.
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