Oil pickup idea

[Colin Mill]

I'd just like to bounce an idea around regarding the oil pickup on the K series engine. The bones of the idea is as follows:-

 

Replace the circular pickup thing on the end of the pickup pipe with a short length of pipe T'd onto the end of the pickup pipe and running across the bottom of the sump to provide pickup points at left and right of the sump. Fit weighted flap valves to the ends of the pipe so that under cornering forces the flap on the inside of the turn is pressed onto the end of the pipe to close it off so that air cannot enter the pipe at that end but the oil can be drawn from the end at the outside of the turn where (hopefully there is still some oil)

 

Clearly it needs much refinements:- a cross link between the two valves to prevent them both becoming closed together; making the cross pipe oval to keep the pickup shallow; arranging enough weight to actuate it reliably; ensurung the flaps are sufficiently airtight etc.

 

I would be interested in anyone's thoughts.

 

Colin

 

Edited by - Colin Mill on 4 May 2005 12:04:27

[thinfourth]

Tricky to machine but defiantly doable

 

okay instead of a pipe T i would have a section machined T is shape

 

Lets say a nominal inside diameter of 12mm then at either end have a support drilled with a centre hole then through this hole a rod the rod being about 10mm longer then the pipe and at either the end of this rod have a plug.

 

Now the plugs would be nice and heavy so they slide easily under force. Also instead of having the valve plugs inside a pipe you could just have it at the end of the pipe so it is submerged in oil.

 

The main problem i see is getting the plugs to move as there will always be a lower pressure in the pipe then the sump. This will not be balanced by the open plug as the closed plug will be have more force on it as a closing pressure since it will be sealed where as the other end will be open.

 

I say most of the above from 70% engineering experience and 30% guess work.

 

other ideas could be a form of float valve but you might not have enough room in a sump to pull this off.

 

Sod the heater wheres my shades

[Kevsta]

Could the oil not be diverted differently so that it went through the apollo tank first and then through the pump so that the apollo became more like a dry sump tank and as it has an oil reserve you could use the reserve which would allow the oil pressure and flow to stay the same and so it would just be that the tank would start to empty until the car became straight again and so the oil levels would level out again...?

 

This is 10% theory and 90% guess work!

[Colin Mill]

Hi Thinforth

 

I'm not sure the pressure difference between the sump and the inside of the pickup will be too bad so long as we get the dimensions of the ports right as the pressure drop is (I think) only due to the flow resistance of the oil into the ports and down the short length of the pickup. Unfortunately, I don't have a figure for the flow rate into the pump. Also, I don't have the oil viscosity in units I understand (like Ns/m^2 or poise) - all I have is that the viscosity of olive oil is 84 Ns/m^2 which I suppose would be a starting point.

 

 

 

Hi Kevsta

Unfortunately I'm not up to speed as to how the apollo is normally plumbed. Could you explain the system to me please.

 

Colin

 

[Peter Carmichael]

The Apollo tank has to exist on the pressure side of the pump in order to de-aerate. Or at least it needs to have the vent connection attached to a lower pressure than its operating pressure and that low pressure point has to be a suitable place for recycling oil into the crankcase.

 

Any sort of twin pickup setup means that at some point one of the pickup ends is definitely not going to be submerged (worse than the current single pickup in the middle). This means that you have to be better at keeping the air out than just random chance and surge in the sump would manage with a single pickup.

 

A method that would work for running multiple pickups from a single scavenge pump stage would be to run spring loaded valves at all the pickups. This will result in some air being scavenged all the time, but in a dry sump system this is normal. I don't believe the sort of setup being described is a starter for a wet sump, unless you also have a chance to redesign the oil pump (pressure relief valve etc.) to have massive extra capacity (to cope with scavenging air sometimes).

 

Nice tries though.

[Colin Mill]

Hi Peter

 

Fair point, but if you arranged that the 'inside' pickup was shut off say for anything over say 0.25g cornering the pickup would be closed before it became uncovered, especially if you did not try to get the pickups too close to the sides of the sump. So long as the pickup was designed not to 'store' air when it was re-covered I would not tend to admit air into the system on coming out of the turn. I'm encouraged by the experience I have from much simpler 'clunk' fuel systems on model helicoters and aircraft where a single weighted pickup is used on the end of a flexible pipe. Such systems have to cope with all manner of aerobatics including sustained upright, inverted and knife-edge flight and a momentary loss of continuity of supply could leave you with an engine re-build size bill.

 

 

[thinfourth]

If you had a flat bottom to where the pickup was and had a shuttle valve as i described earlier then if you got the weighting right then when the oil was pushed across to one side of the engine the lower pickup would be open and the upper closed

 

 

 

Slightly OT but have never seen inside an apollo tank i and not sure of what is inside it. I know it has an in and an out as well as a vent back to the cam cover. This vent comes from the top of the apollo which lets any gas escape from the oil system back to the sump.

 

Now as a engineer i would guess the following might be a bit better. Instead of the vent being at the top move it down to about halfway down. So when the apollo starts to press up the top half of the tank will be full of air. this air will then act as a spring and will compress storing pressure energy now when the oil pick up gets partially exposed and starts to drag in some gas then it will build up and once it reaches the vent it will be returned to the sump as per normal apollo operation. Now when the pump looses suction completely the air spring will then push the oil around the oil system.

 

 

 

Sod the heater wheres my shades

[Colin Mill]

Sounds like the expansion tank on a pressurised hot water system They use an inflated bladder as the airspring. Now it just so happens I have one in the loft

[StewartG]

Rather than blocking the inside, air sucking pickup, mechanically with sliding weights how about using an external g force sensor to electronically control valves in the two pickups?

[Peter Carmichael]

So when the apollo starts to press up the top half of the tank will be full of air. this air will then act as a spring and will compress storing pressure energy now when the oil pick up gets partially exposed and starts to drag in some gas then it will build up and once it reaches the vent it will be returned to the sump as per normal apollo operation.

 

It will also be lighter and have smaller oil change bills.

 

Why not have a tube inserted from the top of the normal Apollo. This would allow the pickup to stay central where it is assumed the majority of air will collect when the oil is swirled in the tank.

 

Do you think there would be concerns regarding flutter on the pressure relief valve from it now having a compressible spring to work against? And of course your air spring is not preloaded, unlike an Accusump, so the actual volume displacement at useable pressure would be er... small?

 

One thing that this discussion has been leading me to wonder is... if to get the whole thing working properly, you really do need two pumps (whether dry sump or otherwise), would it be more efficient to have one of those pumps pumping a small volume of air extracted from aerated oil as opposed to a scavenge pump pumping all the oil you ever circulate, mixed with that self same air - i.e. traditional dry sump vs. swirl tower (Apollo type device ) on the sump side of the pressure pump.

[elise_s1]

is there a spacer available for the Caterham sump?

I'm thinking about Tor project of raising the engine... you raise the engine by 8 mm and fit a 8 mm spacer between sump and block. Lowering the pickup by 8mm you end up with 8mm worth of extra oil (1 litre?) in ALL conditions.

Or am I missing something?

Carlo

 

Edited by - elise_s1 on 4 May 2005 15:46:13

[Colin Mill]

Hi Stewart

 

Yes, I don't see any problem in that. Actually ,Analog Devices were nice enough to send me some samples of their new two-axis accelerometers (+-2g on each axis). I've been thinking about knocking one up into a lateral g display but perhaps this would be an even better use for them (BTW these accelerometers are cheap - about $4 in quantity)

 

You do the mechanics and I'll do the electronics.

[Paul Ranson]

It seems an awful lot of energy is being put into schemes to avoid dry sumping when dry sumping is actually the only sensible solution. Simple, off the shelf, adds value to the car, cheap in comparison to most upgraded engines, added bonuses of reduced windage losses.

 

I'm assuming that a scavenge pump is actually cheap to run in the context of likely power output. The Peter Wright book on the 2000 Ferrari F1 car shows that V10 engine using 12 scavenge pumps which implies they are relatively cheap in both power and weight, I've no idea of actual figures.

 

Paul

[Colin Mill]

Hi Paul

 

Yes, dry-sumping is a very obvious solution to the problem but it also seems a sledgehammer to solve what is a rather simple requirement - a reliable oil supply. I'm not sure what the weight penalty to dry-sumping is but as a retro-fit its rather more work than a sump-off type mod would be. The residual sand in the bell tank is a bit of a turn-off as well. I like the challenge of finding a simpler, lighter, cheaper and easily fitted alternative.

[Paul Ranson]

I don't think it's a sledgehammer when you consider some of the suggestions above!

 

OTOH I'm extremely wary of hopeful innovation on the lubrication front. The effort involved in making a multiple pick up system with valves work reliably and without damaging your engine in the testing seems out of proportion to the results.

 

Good luck anyway.

 

Paul

[Colin Mill]

Hi Peter

 

Sorry for my being a bit dense on this one - can I just check - are you suggesting that you put the swirl tower on the intake side of the pump so that its below ambient pressure and then use a small air pump to extract any collected air from the top of the tower?

 

Colin

[Myles]

So why are accusumps out of fashion? OK, they add weight and complexity - but what's the downer? I've just taken it as read - from 7 folklore - that they're pants...

 

Project Scope-Creep is live...

 

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[Tony C]

I agree with Paul - I dry sumped my 2003 SV 1.8 K-Series after the first time I changed the sump foam, which I consider to be a nasty and cheap piece of engineering - dictated, as I undrestand it, by the requirement of the shallow sump pan for Caterham use ground clearance and intended to decrease aeration rather than prevent oil surge.

 

I use my car mainly on the road, with occasional track and airfild days. I went the "Pace" route and like the engineering and installation. Sure it cost £1,000 + but I feel confident that my engine lubrication is well taken care of.

 

This thread and other similar threads may just be speculative, but researching and developing a viable alternative to standard wet sump lubrication is fraught with potential engine terminating possibilities.

 

Some posts have reported OP fluctuations with the aluminium baffle fitted instead of the foam - my understanding is that the foam is merely for de-aeration, so I can't really see how refitting the foam will prevent OP fluctuations. (I guess that having air free oil will help, but uncovering of the pick-up pipe is likely to be a bigger threat). I wonder how the baffle was designed and developed - no critisism intended - just curious. I'm a little dubious that the hinged surge valves can fully prevent the pick-up becoming uncovered - there seems to be a few gaps.

 

Despite the cost, I'd go for a dry sump 😬

 

BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery)

[Colin Mill]

Can't help thinking that some good alternatives to dry sump must have been worked out - I'm not sure of current rules but in the 70's Group 2 saloon cars were not permitted a dry sump (unfortunately for the Broadspeed Jag).

[stevefoster]

My DS system only added 1.65 KG's (dry).

I can run 4l of oil (as the wet sump was approx)or 6 or 7 if I want to. I didn't notice any power lost at all.

 

What you are describing reminds me of the Radio Controlled plane's fuel pick up. A weigh on the end of a silicon tube in the cylindrical tank. It would fall to wherever the pull of gravity was

 

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[Paul Ranson]

It's a pretty safe bet that in any form of competition where dry sumping is outlawed the engineering of the lubrication system costs much more than the illegal alternative. I think WRC is an example.

 

Paul

[Tony Whitley]

If you're worried about the cost of a dry sump system, read the PPC mag article on the DIY dry sump 😬

[TorAtle]

Paulo,

 

adding a 1cm spacer between the sump and the block would add 1 litre or so of oil but unfortunately the sump is also mounted by two bolts to the bellhousing. Nice thinking though

 

Thinking out loud. Is it possible to leave sump and oil pickup as is, remove the Rover oil pump rotor and use a sandwich plate (like on an apollo-setup) for scavenge and pressure in? Add a 1+1 stage dry sump pump and a tank and you have a dry sump setup.

 

 

[Colin Mill]

Just a few numbers to throw into the problem. Figures I have for maximum oil pump throughput range from 10 to 17 litres per minute at max rpm - suggests we are turning the sump contents over 2 or 3 times per minute. The tests mentioned on page 7 of the April 2005 issue of LF can be further analysed as

follows:- If they were in the parish of 1g cornering at 52mph (23m/s) then the circumference of the 'roundabout' being followed will have been about 340 metres. So the 5 laps it took to see an oil pressure dip will have taken about 1 minute 15 seconds (longer if - dare I suggest it - they were pulling less than

1g). In that time the sump contents must have been turned over several times. I find that very interesting. If the pickup is coming out of the soup right from the word go I reckon you would see the pressure dip a lot earlier. So it looks as if the level in the sump is initially OK but falls gradually over that minute? Is it that the oil can't fall past the windage plate well enough during cornering? I notice from the following website that windage tray design is non-trivial.

 

http://circletrack.com/nls/76818/

 

Should we be looking at the windage tray rather than the pickup?

 

[Tony C]

Maybe the cornering 'g' force is slowing the rate of return of oil to the sump. I'm assuming the inside of the engine has ridges on which the lateral 'g' would be holding the oil.