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Old   July 4, 2017, 19:25
Default converge compression ratio
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xinkai liu
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why when I want to move the piston toward compression ratio the piston moves very ridiculous, by the way, I already make the cylinder close
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Old   July 5, 2017, 03:36
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Please define "ridiculous".

Do you have specified the correct piston moving direction?
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Old   July 5, 2017, 07:52
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I have set the piston move as z direction, ridiculous means that when it moves it will over the head or go down a lot. the compress ratio is always stuck in 3 my target compression ratio is set at 10, do I need to set the TDC first and if so how can I set the TDC position.
many thanks
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Old   July 5, 2017, 08:55
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The Piston has to be in BDC position, while the Valves are in closed position.
The minimum Lift (0.2 or 0.1 mm) causes a slightly higher compression ratio as originally defined in CAD.

Do you have selected the correct boundaries that form the combustion chamber?
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Old   July 5, 2017, 09:57
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I think I have set the correct boundary, but the compression ratio is still only 3 I don't know why, have you meet this kind problem before?
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Old   July 5, 2017, 11:26
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No, i never had this problem.
Do you have correct units for bore and stroke in the engine.in file?
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Old   July 5, 2017, 11:46
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I would also suggesto to check che model dimension: try to measure the cylinder diameter to double check you're working with your desired units
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Old   July 5, 2017, 12:09
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after I check the diameter it works, thank you guys, many thanks
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