Intellectual engine questionnnnn...

[Jorgen]

If you are defining "stopping" to have zero vertical velocity then it stops. Just not for any period of time.

boom

[Wergen7]

i'm saying theoretically it stops at the top and bottom for an infinitely small amount of time. basically immeasurable amount of time. but in practice, i would guess there is slight side to side motion in the cylinder because of the way a crank is and the rod being connected to that. so it is probably always in motion in some direction whether it be vertical or horizontal. its tough because a crank is circular and the piston is vertical. but the rod is like both depending on which side of it you're looking at

[kronus]

Guys... come on guys.

Thank you for reminding us of Newton's second law. So in a sine-like wave form, TDC and BDC still have a derivitave of zero, yes? So what's the acceleration of an object with zero velocity? Mr. Newton's second law makes it pretty clear what the net force is when something isn't accelerating.

well, no. if position = sin(t), velocity is δposition/δt = δ/δt sin(t) = cos(t). acceleration is δvelocity/δt = δ/δt cos(t) = -sin(t).

if position is


acceleration will be that wave flipped, with maxima and minima exactly where TDC and BDC occur in the position plot.

[quickervicar]

I fail to see anything in this thread yet that would constitute an "intellectual engine question". I am thoroughly disappointed, this thread fails.

Does the piston actually exist? Or are we just imagining it existing because that is all we know of internal combustion? Can that same piston exist in two different cylinders at the same moment in time?

[Wh33lhop]

Seems like by F=ma, the force must be zero at some point. Not that it matters. :twisted:

Acceleration is NOT velocity. You are confusing the two.

Guys... come on guys.

Thank you for reminding us of Newton's second law. So in a sine-like wave form, TDC and BDC still have a derivitave of zero, yes? So what's the acceleration of an object with zero velocity? Mr. Newton's second law makes it pretty clear what the net force is when something isn't accelerating.

You too.

[slammin.e28]

Don't be close minded ya'll.



I think I'm going to set myself to proving it doesn't stop....


....in my next life.

[Wh33lhop]

I fail to see anything in this thread yet that would constitute an "intellectual engine question". I am thoroughly disappointed, this thread fails. I had hopes for a topic like harmonic resonance tuning for ideal peak placements or something.

Sounds like you're way too smart for the rest of us.

Rod ratio has nothing to do with the vertical loads placed on the piston at the wrist pin.

Well, actually it does a little bit, since it will alter the piston's stroke pattern (smaller rod ratio will make the piston dwell more at tdc/bdc); however, that's not what I said.

Does the piston actually exist? Or are we just imagining it existing because that is all we know of internal combustion? Can that same piston exist in two different cylinders at the same moment in time?

:rofl:

[ak-]

Guys... come on guys.

Thank you for reminding us of Newton's second law. So in a sine-like wave form, TDC and BDC still have a derivitave of zero, yes? So what's the acceleration of an object with zero velocity? Mr. Newton's second law makes it pretty clear what the net force is when something isn't accelerating.

Well Newton's laws are still technically considered theories.

So yeah, fuck everything!

[TwoJ's]

Acceleration is NOT velocity. You are confusing the two.

You too.

Not confusing anything (ACTUALLY CONFUSING SIMPLE MATH). Did you take calc and/or physics in high school? Or 101 stuff in college? dv/dt= Acceleration. The slope of a tangent line of a velocity curve (dv/dt) is acceleration. So tell me, what is the slope of a line that is horizontal (TDC and BDC).

Again... not confusing anything. If V=0 (even just for an instant), then maths and physics tells us that acceleration is zero. And what is the net force of something that isn't accelerating? Zero.

So... when V=0 it follows that a=0. When A=0, it follows that F=0. Simple as that.

[kronus]

Not confusing anything. Did you take calc and/or physics in high school? Or 101 stuff in college? dv/dt= Acceleration. The slope of a tangent line of a velocity curve (dv/dt) is acceleration. So tell me, what is the slope of a line that is horizontal (TDC and BDC).

Again... not confusing anything. If V=0 (even just for an instant), then maths and physics tells us that acceleration is zero. And what is the net force of something that isn't accelerating? Zero.

So... when V=0 it follows that a=0. When A=0, it follows that F=0. Simple as that.

velocity isn't horizontal at TDC and BDC, it's at the zero point, with a nonzero slope. read my post again, then read his post again.

[TwoJ's]

Well Newton's laws are still technically considered theories.

So yeah, fuck everything!

Easy there Descartes.

[TwoJ's]

velocity isn't horizontal at TDC and BDC, it's at the zero point, with a nonzero slope. read my post again, then read his post again.

DERP, I'm retarded. All previous statements retracted.

[kronus]

glad it clicked :)

[ak-]

easy there descartes.

8)

[TwoJ's]

My former teachers/professors would be embarrassed/disappointed.