Very interesting and marries common sense with some form of data prediction analysis.
One comment about some of the verbiage. In the first paragraph, they state:
"
The resistance offered by the filtering element or filtering material is the main source of pressure drop in the lubrication system." I take exception to that. Think about it. If I removed my oil filter (replaced it with a hollow canister to complete the circuit), would the pressure gage go to near zero? No way. The engine oil pathways are the main restriction in the system as a whole, not the filter media. If your engine ran 60 psi pressure at 2000 rpm (like my diesel), would removing the filter (but closing the loop) make the pressure drop to zero? NO! I'll bet the filter unit as a whole might be good for a few PSID. The bulk of the pressure is developed by the resistance to flow in the engine itself. The "lubrication system" to me means the oil pan, pump, filter, pathways; everthing the oil touches. The pump puts up the potential (pressure) and it gets dumped back to atmospheric pressure only AFTER it's released to return to the pan via port holes to drain back channels. The bulk of the pressure is released at the oil cooling jet holes squirting the pistons, the pushrod holes lubricating the upper head components, the crankshaft and con-rod holes, etc. Which do you think is more likely in a system that has 60 psi?
1) 3 psid across the filter and 57 psid dump as the engine release the oil for return
2) 57 psid across the fiter and only 3 psid at the return?
Yeah, the numbers are ficticious and probably vary a bit, but the concept holds true. The BULK of the pressure drop is due to the engine components releasing the oil back to atmoshperic pressure. The filter is a small amount of that drop in the
system.
I think what they meant to state is that
the filter media is the greatest restriction in the filter unit (not the whole system). The media creates more pressure drop than does the ADBV, passage holes, etc. In the last paragraph, the do clarify it a bit:
"
The pressure and velocity distributions indicate that the highest pressure drop through the filter occurs through the filtering element, compared to the other restrictions in the unit." Notice that here they clearly define this PSID "in the unit" (meaning the filter itself) and not the "system" as a whole.
Nitpicking, yes. But isn't that what BITOG is about?
