Wedg1e
They call me Mr. Bodge-angles
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Why? Didn't you like the Landrover injection system?
- Thread starter whensparksfly
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super noob
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No, its not getting a landrover engine anymore its cadillac
whensparksfly
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whensparksfly
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dose anyone know much about this setup or more about this sort of venturi effect
i think this method is that as the fuel is returned it drags the fuel from the tank into the center with it.
i think this method is that as the fuel is returned it drags the fuel from the tank into the center with it.
Bill briefly explained how the venturi effect is used in fuel tanks back in post #24. Principle is exactly the same as the venturi in a caburettor...
It's used to continually refill the fuel pick up chamber (in tank "swirl pot") from other areas of the tank and, done right, the pump can almost literally run the tank dry even when the vehicle is sitting on a steep hill
It's most commonly illustrated with a saddle tank design as you obviously need a way of getting fuel from the 'passive' side of the tank to the delivery side and they're commonly referred to as a 'venturi jet pump'...
http://www.freepatentsonline.com/6607005.html and http://www.hessh.de/Corvette/FuelTankSystem.pdf explain in detail while
shows a home hade one in action
The pic in post 43 is a simple fuel pick up baffle. Tank shape plays a large role but as long as there are no 'dead areas' for fuel to get trapped they work very well by themselves (better than 'sumps' in the tank) and negate the need for additional swirl pots. Venturi jet pumps can be used with them to scavenge any dead areas created by tank shape- long and shallow, scalloped to fit around/over chassis rails and full on saddle tank shape for example. With OEM tanks they're usually made of plastic and while they can be as simple as that example in ally they're often deceptively clever units that contain a strainer to prevent any crud in the tank from getting picked up as well as being a plumbed in a way to centrifuge/swirl the fuel to help deaerate it.
It's used to continually refill the fuel pick up chamber (in tank "swirl pot") from other areas of the tank and, done right, the pump can almost literally run the tank dry even when the vehicle is sitting on a steep hill
It's most commonly illustrated with a saddle tank design as you obviously need a way of getting fuel from the 'passive' side of the tank to the delivery side and they're commonly referred to as a 'venturi jet pump'...
http://www.freepatentsonline.com/6607005.html and http://www.hessh.de/Corvette/FuelTankSystem.pdf explain in detail while
shows a home hade one in action
The pic in post 43 is a simple fuel pick up baffle. Tank shape plays a large role but as long as there are no 'dead areas' for fuel to get trapped they work very well by themselves (better than 'sumps' in the tank) and negate the need for additional swirl pots. Venturi jet pumps can be used with them to scavenge any dead areas created by tank shape- long and shallow, scalloped to fit around/over chassis rails and full on saddle tank shape for example. With OEM tanks they're usually made of plastic and while they can be as simple as that example in ally they're often deceptively clever units that contain a strainer to prevent any crud in the tank from getting picked up as well as being a plumbed in a way to centrifuge/swirl the fuel to help deaerate it.
bill_gj
Tired and irritable
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Thanks for the ref Hotrodder - here's a couple of links to systems I designed for a certain Midlands car maker for engines up to 500bhp.
The first link shows diagrams of a jet pump and the second an in-tank layout.
Click the 'mosaics' link in the left hand panel for the diagram.
http://worldwide.espacenet.com/publ...30102&DB=worldwide.espacenet.com&locale=en_EP
http://worldwide.espacenet.com/publ...P&FT=D&date=20030416&CC=EP&NR=1302354A1&KC=A1
The first link shows diagrams of a jet pump and the second an in-tank layout.
Click the 'mosaics' link in the left hand panel for the diagram.
http://worldwide.espacenet.com/publ...30102&DB=worldwide.espacenet.com&locale=en_EP
http://worldwide.espacenet.com/publ...P&FT=D&date=20030416&CC=EP&NR=1302354A1&KC=A1
whensparksfly
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that setup i the video seem to work good with venturi jet feeds from each side and the fuel return all retuning fuel to the collector in the center.it seem to be a sealed collector in the video would it be better to use the one in the picture i posted with the fuel returning just before the entrance to the collector dragging in all the fuel close to the collector.
whensparksfly
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What's best is all dependant on the design of the actual tank... the example in the vid is massively long compared to it's height and so really needs fuel scavenging from the ends to prevent a chunk of it's capacity being wasted. Tha tank in my daily driver (70 litres) has plenty of depth relative to it's height/width and so there's little need to scavenge fuel from the ends. Early examples were very similar to the pic in post #43, the only real difference being that the return was plumbed in via a venturi so it still stands a chance of actively filling the pot when the fuel in the tank is being sloshed about etc. Later they changed to this set up http://www.w124performance.com/service/w124CD1/Program/Engine/LHIS/47-0010.pdf which is more refinement than anything. The pump is outside of the tank in either case on these.
The two beetle tanks in my photo albums... no proper venturis on either of them as it'd be creating work for the sake of it. The shape of the tank means that hills don't bother it unless you're driving 'across' them with the car leaning sideways at 45 degrees and on fumes. There is a venturi pump in this tank
as the space it had to fit into had a chassis rail in the way which wasn't compatible with the requested tank size unless i scalloped the tank over it which created a dead space (haven't got any other pics of it)
If it weren't for the fact that the brief for those tanks was something with an OE flavour/they didn't want to buy new a pump etc i'd have used a modern 'drop in' fuel delivery module and saved myself even more work as you can have a self contained unit that incorporates everything including sender, plumbing and a venturi circuit to actively fill it's resevoir through a built in filter
The two beetle tanks in my photo albums... no proper venturis on either of them as it'd be creating work for the sake of it. The shape of the tank means that hills don't bother it unless you're driving 'across' them with the car leaning sideways at 45 degrees and on fumes. There is a venturi pump in this tank
as the space it had to fit into had a chassis rail in the way which wasn't compatible with the requested tank size unless i scalloped the tank over it which created a dead space (haven't got any other pics of it)
If it weren't for the fact that the brief for those tanks was something with an OE flavour/they didn't want to buy new a pump etc i'd have used a modern 'drop in' fuel delivery module and saved myself even more work as you can have a self contained unit that incorporates everything including sender, plumbing and a venturi circuit to actively fill it's resevoir through a built in filter
Shox Dr
Chief Engineer to Carlos Fandango
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I don't know who designed the Petrol tank in my Pickup, he knows his stuff, and I doubt there's even a baffle in it. I have run out of petrol twice now,* and where wasn't a wiff of petrol left. 
*(because of the wonky gauge)
*(because of the wonky gauge)
whensparksfly
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Ive been missing with a water pump a different venturi setup got it to work but what is the best design to use as my one ist very good.do you make the venturi or buy in
I make 'em when i have to as things designed for ponds/water pumps are inevitably plastic but the flavour is never stated so compatability with todays ethanol blends of fuel is unknown etc. Also by machining a short length of ally bar into something venturi shaped i can do all the internal tank plumbing in welded hard line
Again can't comment on the 'best design' when the shape/layout of the tank is unknown. That comes first as it's dictated by the available space etc, then i'd decide on pump/sender/plumbing and worry about venturi pumps if/when it becomes apparent that something will be needed and i can't do it with an off the shelf modern fuel pump module. The pic in post 43 may be more than good enough and if not then between that example and a 'proper' venturi tube have a look at a blowtorch nozzle...
which uses the venturi effect to mix air with fuel gas. Quick and simple to approximate and should pull more fuel into the return stream than simply tucking the return into an oversize hole in the pick up baffle. If you want to buy something instead of making it then look at venturi nozzles for blow guns If the tank shape results in the need to scavange from dead areas of the tank then the choice is a smaller tank or 'proper' venturis and loads of internal plumbing.
If the tank is shaped like the one in Shox Drs pickup (tall and narrow squeezed between the bench seat and back of the cab) it'll be self emptying like the beetle tanks i mentioned previously and just need a simple baffle around the outlet with fuel injection to do the same job that float bowls in carbs- deal with temporary fuel surge from cornerning etc
Again can't comment on the 'best design' when the shape/layout of the tank is unknown. That comes first as it's dictated by the available space etc, then i'd decide on pump/sender/plumbing and worry about venturi pumps if/when it becomes apparent that something will be needed and i can't do it with an off the shelf modern fuel pump module. The pic in post 43 may be more than good enough and if not then between that example and a 'proper' venturi tube have a look at a blowtorch nozzle...
which uses the venturi effect to mix air with fuel gas. Quick and simple to approximate and should pull more fuel into the return stream than simply tucking the return into an oversize hole in the pick up baffle. If you want to buy something instead of making it then look at venturi nozzles for blow guns If the tank shape results in the need to scavange from dead areas of the tank then the choice is a smaller tank or 'proper' venturis and loads of internal plumbing.
If the tank is shaped like the one in Shox Drs pickup (tall and narrow squeezed between the bench seat and back of the cab) it'll be self emptying like the beetle tanks i mentioned previously and just need a simple baffle around the outlet with fuel injection to do the same job that float bowls in carbs- deal with temporary fuel surge from cornerning etc
whensparksfly
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my tank will be a simple rectangle with a flat bottom will not be tall to keep center of gravity low.thanks for the blow gun pic explains what im doing wrong
