Yeah well, even ancient British motorcycles that featured dry-sump lubrication incorporated such systems.
& recip' aero-mills, esp' those with the complicating factors of aerobatic/-G/altitude/supercharger pressure to deal with..
There is not much problem created by the crankcase air volume being moved about by the motion of the pistons. While some pistons are moving up other pistons are moving down, so the net change in crankcase total air volume at any given instant is not that great. Of course, having a crankcase pressure below that existing in the intake manifold will help prevent oil being drawn past the piston rings or valve guides. But with the turbo engines currently used in F1 the intake manifold pressure is usually well above ambient, so this is not really an issue.J.A.W. wrote:Not only the oil, but with the air which is being wastefully pumped around under the pistons..
..a meaningful degree of vacuum - can significantly reduce the density/drag there..
..as well as improving piston ring sealing.. ..& pressure induced oil leaks..
"Windage" losses are not the result of crankcase pressure fluctuation rather air being moved back and forth plus the aerodynamic drag of parts moving through the air.riff_raff wrote:There is not much problem created by the crankcase air volume being moved about by the motion of the pistons. While some pistons are moving up other pistons are moving down, so the net change in crankcase total air volume at any given instant is not that great.J.A.W. wrote:Not only the oil, but with the air which is being wastefully pumped around under the pistons..
..a meaningful degree of vacuum - can significantly reduce the density/drag there..
..as well as improving piston ring sealing.. ..& pressure induced oil leaks..
riff_raff wrote:
There is not much problem created by the crankcase air volume being moved about by the motion of the pistons. While some pistons are moving up other pistons are moving down, so the net change in crankcase total air volume at any given instant is not that great.
The windage losses produced by the rotating components in an engine crankcase are not due to "aerodynamic drag", instead they are primarily hydraulic losses created by the surfaces of the rotating components impacting droplets of lube oil dispersed in the air volume, and liquid oil films attached to the sump surfaces, at high velocity.gruntguru wrote:"Windage" losses are not the result of crankcase pressure fluctuation rather air being moved back and forth plus the aerodynamic drag of parts moving through the air.