RE: interference fit

[frankbauer@thevine.net]

glen sez:
>Mebbe I am wrong because it may be possible for the piston to go from upward
>deceleration to downward deceleration without reaching zero acceleration at
>while it is instantaneously at rest at TDC and before downward deceleration

acceleration means the speed is increasing.
deceleration means the speed is decreasing.
the fastest piston speeds occur near the halfway point of the stroke.
therefore, the piston accelerates from TDC to ~ halfway down, then
decelerates to zero at the bottom of the stroke, accelerates again until
~ halfway up and decelerates again until zero vertical displacement
occurs at TDC.

zero velocity occurs when change of displacement over time is zero.
zero acceleration occurs when change of velocity over time is zero.
if you make a graph of displacement and velocity of the piston over the
time period of a single engine rotation, these zero slopes are defined
wherever the curve is parallel to the time axis.  these also happen to be
the maximum and minimum points on a cyclic curve such as this.

frank

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