Originally Posted By: Shannow
Originally Posted By: ZeeOSix
Put a motor on a stand and take the oil pan and valve cover off of it, then pressurize the whole oiling system. What you see is every journal bearing flowing oil like mad because they are all being force fed oil through the bearing's clearance. Based on your belief, there would be no flow seen in that scenario because the bearings because the engine wasn't rotating. There's a big disconnect there and erroneous thinking.
What ???
Where have I ever said that applying pressure to the galleries of a stationary engine doesn't create flow ?
Of course it does...
In the other thread you said:
Originally Posted By: Shannow
again...the pump supplies full oil galleries.
again...the bearings draw off from those galleries what they need.
again...the artifact of them needing less than the pump delivery volume is oil pressure.
again...a pre-oiler fills the galleries...doesn't lubricate anything, nor does pressure/volume of the oil pump.
That clearly tells me (as well as many other of your posts) that you don't believe a pressure fed bearing gets increased oil flow through it from a higher supply pressure. Your premise is that the bearing "sucks" the volume it needs from the supply gallery based on it's side leakage, and the flow through it isn't influenced by the supply pressure, no matter how high the supply pressure is. But if that was really true (which it's not), then in the scenario shown in the YouTube video there would be zero flow through the bearing because all the bearings were stationary and unable to suck oil in like they normally would from their rotation action. Isn't that your whole position in these discussions.
I've shown that if the supply pressure is increased, then so is the flow through the bearing. Equation shown here - same equation (10-20) shown in the other thread:
http://www.mathworks.com/help/physmod/hy...w.mathworks.com
Increase the supply pressure p, and flow q has to increase. Simple case that a pressure difference causes fluid to flow. Still holds true when the engine is running.
Even in a pressure fed bearing, it's rotation still does help "suck in" oil from the gallery, but it's very insignificant compared to the high supply oil pressure forcing the flow through the bearing. If the oil gallery was only at atmospheric pressure (ie, gauge pressure = 0), then the rotation of the bearing and he partial internal vacuum it produces would be the only driving force to draw ("suck") oil into the bearing. That's why Figures 10-16, 10-17 and 10-18 discussed in the other thread are not valid for pressure fed bearings, but are derived to only be valid for atmospheric supplied bearings. The equation shown in the link about (same as equation 10-20 in the other thread) is what defines bearing oil volume flow as soon as positive supply pressure is involved. It's clearly discussed in the machine design handbook I referenced.
Originally Posted By: Shannow
Your static crank, electric oil pump has SFA to do with what's happening in a spinning engine...that fact that you think it's demonstrative is quite telling really.
What you're failing to see is that a positive supply pressure causes more oil volume to flow through the bearing ... and that's also true when the engine is running. The hydrodynamic action inside the bearing is still going on when it's rotating even in a pressure fed situation. The bearing doesn't care much about the supply pressure in terms of lubrication unless of course the supply oil volume is way too low (due to low pressure), which could cause lack of lubrication and/or over heating of the bearing.
Originally Posted By: Shannow
But the things that happen inside operating engines are
dynamic ... that's why Honda said that when they increase the RPM, they increased the pressure to overcome the centrifugal action from the big end throws...need enough pressure to overcome the dynamics within the crank drillings.
Big end throws
http://www.tytlabs.com/english/review/rev383epdf/e383_044suzuki.pdf
clearly not "pressure fed", as for significant parts of the rotation, there isn't any pressure at all.
Yes, Honda increased the oil pressure to the bearings to overcome the decrease in supply pressure right at the bearings due to increased centrifugal force from the increased RPM, and most likely to ensure the oil volume was still high enough for adequate cooling. If they didn't increase the supply pressure then the oil volume being forced through the bearing would be too low during high RPM and load for the bearing to survive as they wanted. Now if the bearings only "sucked in" what they wanted from the galleries due to their small internal vacuum, do you really think they would survive in an engine like that Honda F1 engine? I don't think they would last one 30 second blast to red line. That's why Honda is force feeding those bearings with 130 PSI.