oil And g-force

[hardhgear]

I heard that the geforce affect the oil in the enginge in corners. is that true or not and how this happend

[Monstrobolaxa]

Well since G'force affects everything in the car....probably it's true!

The highest aceleration the engine feels is in the pistons when they change the direction of their movement! The oil due to the piston rings also feels this aceleration.....but when cornering probably the oil is slightly pulled to one side of the piston.

In the case of a F1 engine the oil sump is a dry-sump system...which means the oil isn't stored in beneath the crankshaft....(this is an advantage cause it you can make the engine lower cause there isn't the necessity of a sump area)....so the oil is picked up and "injected" into the piston area (after cooling and filtering, the area is not the combustion chamber). So the slushing of oil around the sump doesn't happen.

So with no sump and oil slushing around the only way that g'force might influence the oil performance is by bringing more oil to one side of the piston then to the other.

In any case this might only be a problem in fast high g corners....cause the slow corners usually only reach high g's for a limited time and in slow corners there's a drop in the rpm....and oil "injection" into to the piston area is proporcional to the rpm....so the oil distribuition around the piston probably won't be too much affected....but in any case my opinion is that it might influence the oil distribuition around the piston....pulling/pushing (depending on your referencial) more oil to one side of the piston then to the other.

[Guest]

with g-loads of 3-4 Gs sustained ,oil sticks at thw walls and starts to go down to the bottom of the engine when the g-loads dimiísh only! So theres´a lot of oil in unusual places with no chance to get picked up by the strongest oilpump.....
very tricky stuff...

[pyry]

so at the end of the race half the oil has been drained to the bottom of the engine? wouldnt bet my money on that with all respect... how exactly does a drysump system work, id be grateful on somekind of a drawing or something where it shows how the oil circulates in the engine.

[Guest]

no ,you did get that wrong ,the oil sticks at the walls during cornering and acceleration,of course it will flow down at the end of a straight when
acceleration diminishes ...but with sustained 4 gs no oil will flow down it sticks to the wall.

[Monstrobolaxa]

in a dry sump engine the oil flows to the bottom of the engine like in a wet sump engine the only diference is that in a dry sump there is a 1 or 2 oil pumps removing the oil from the sump!

[Guest]

On the dyno ,you´re completely right.
But i remember some Mrio illien saying:You wouldn´t believe where the oil of an engine gets trapped during cornering on a high speed corner....
The oil goes down by Gravity (1g) but cornering force may be 3.6gs or braking 4gs...so during corneringor braking the oil will not flow down to the pump oil pickups,sorry to say that,It sticks to the wall as long as theres more force laterally then vertically.....simple physics.
Even with 1 g cornering loads the oil in the sump will be at 45°from horizontal .....so what will happen with more force laterally than horizontally ....you hardly have any oil in the pickup area.
The pumps have to be big and powerful and they have to be able to pump foam and splats of Oil very well ,as you won´t get a uninterupted flow of oil...

[Monstrobolaxa]

Yup the guest is absolutly right....while the lateral g's are higher then 1 the oil will tend not to flow downwards.

The thing is that the cyclinders are banked....do in any case the oil during a corner will tend to be pulled down on one bank during one corner and be pulled up in the other bank

An example imagine a 90º engine....

turning right at 3g's.

This means the lateral g's are pulling to the right!

On the right hand bank of the engine the oil is pulled into the crank area with a force of around 2 g's and will be pushed against the wall with a force of around 3g's.

On the left hand bank of the engine the oil will be pulled into the crank area with a force of around 0,8 g's and will be pushed against the wall with a force of around 3 g's...and this case it will have another vertical component pulling the oil up...of around 1,6 g's. So on the left bank the vertical component is 0,8 pulling the oil upward....this means that on a right hand corner the left hand side oil doesn't tend to go into the crank/pickup area!

It's simple geometry! Notice that I have not counted with the friction that the oil has with cylinder walls!

[StiK]

Im not an expert in engines at all, but isn´t the piston who spreads the oil inside the cilinder. What I'm saying is that the oil stiks to the cilinder wall but it also stiks to the piston so the piston pulls/pushes(?) the oil down and so counteracting the effect of G's. That's why viscosity is very impostant in an oil because the amount of oil pushed/pulled(?) depends on it.

StiK

[scarbs]

This the response I got from an F1 engine designer today.....

Oil and G-forces affect two areas, the oil tank and the sump scavenging.

The oil tank is relatively small and as the g-force acts laterally (and vertically at Spa) the oil is forced away from the oil pump and hence starves the engine of oil.

Likewise with the sump Gforce also acts laterally and longitudenally inhibiting the oil from falling down the engine and into the scavenge pumps in the sump.

He didnt mention cylinder wall oiling problems.

Scarbs...

[Lukin]

I read somewhere (one of the BMW pre-race blurbs I think) that 130R provides the greatest effect on oil supply.

[scarbs]

YEs any long corner creates a problem, as does Eau rouge as the cars crest the hil the oil moves upwards in the engine and tank..!

[Kartracer]

The oil tank is relatively small and as the g-force acts laterally (and vertically at Spa) the oil is forced away from the oil pump and hence starves the engine of oil.
Scarbs...

This is not a problem, all engines have tanks that are big enough in this respect. The main problem is oil being trapped inside the engine and causing mechanical problems because of vibration due to the weight of the oil, or impact problems where the misplaced oil is hit by fast moving parts.

[scarbs]

KartRacer, I dont agree with you, my information came direct from a current technical director of a f1 manufacturer

[Kartracer]

KartRacer, I dont agree with you, my information came direct from a current technical director of a f1 manufacturer

Certainly it is an issue, but it is not a problem. I am sure that technical director was confident that the "problem" had been solved, the real challenge is scavenging the engine, not having enough oil in the supply tank.