fuel tank Design

[shiv]

please tell me about how to go about fuel tank design

[shiv]

please tell me about how to go about fuel tank design

[VFR750R]

It should be designed such that it holds fuel, doesn't leak any, and conforms to the rules.


Seriously though, aluminum is a good material and you'll need to put some thought into making sure you can use all the fuel that is in your tank. Common ways are bowls below the bottom of the tank for the pickup, trap doors, and other forms of baffling. Think about where you want the tank in the car before you design the tank so that it fits.

[drivetrainUW-Platt]

remember, you have to be able to get the tank in and out of your frame, so a removable filler neck is a good idea. You have to have an access hole for putting the fuel pump in, but you can also consider running an external pump. It is a dynamic weight since as you burn up fuel it will become lighter, so centering it in the frame will prevent big disturbances in side to side weight changes.

[shiv]

Thank you for the reply, please may u tell me how do i go about the fuel tank design.

[Nitesh]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">You have to have an access hole for putting the fuel pump in, but you can also consider running an external pump. </div></BLOCKQUOTE>


do you guys use submersible pumps also? We had one last year on our car and the judges objected to it, saying they wanted an external one. They just let us make do cause changing the pump at the competition was not possible.

[J. Schmidt]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> do you guys use submersible pumps also? We had one last year on our car and the judges objected to it, saying they wanted an external one. They just let us make do cause changing the pump at the competition was not possible. </div></BLOCKQUOTE>
The rules don't state which type of pump to use. We've never had any problems with the internal pump, except for running it dry accidently and needing to replace it (good thing it was cheep). There is a discussion here (http://fsae.com/eve/forums/a/tpc/f/125607348/m/7376081334/r/7376081334#7376081334) on internal versus external pumps.

[drivetrainUW-Platt]

joel, get on the horn with me, lets get goin on this *%#$ car!

[Nihal]

shiv: I would go about figuring out how much volume you want and where in the car it is going to be placed. After that you will have dimensions for it. You should htne plan on how to get the filler neck to the outside of the car and think about the tilt test to see if it would leak gas.

You are going ot have to think about the fuel sloshing around in there and such. There are fuel cell foams, trap door designes etc. that people have used before. Give those a thought.

[kozak]

So since we are talking about fuel i was wondering about vent/check valves. the rules state that we must have a fuel tank vent, but no fuel can leak out in a roll over. i was looking over the fuel safe web catalog (thanks Mechanicaldan) and i see vent/check valves. Could i use these types like they show or the in line vent/check, or are these valves to slow to shut off during the tilt test.

[CMURacing - Prometheus]

the tilt test works like this:

tilt to 45 degrees, check leaks

tilt to 60 degrees to check rollover. if fuel starts spilling out of the check valve (as it has on our car), someone is asked to close the valve (we did it with a thumb) to prevent leakage.

so the check valve is in case of a rollover, such that fuel will not spill out onto the track.

[kozak]

so your valve didn't work is that what your saying. how were you able to compete, or do they not really care.

[Colin]

THEY CARE! trust me we missed out on a possible win in FSAE-A in 2003 because of a "fuel Leak", and our car had no problem passing the tilt table, so regardless of weather your car passes the tilt test at 45 degrees make sure it doesn't leak fuel while cornering. As is being discussed on another thread, fsae car's are starting to see higher G's than the tilt table test was designed for

[kozak]

well i don;t think there is a check valve in the world that will completely close on a partial incline. so what i was thinking of doing is run a vent hose from the tank or the filler neck up and around the main roll hoop like in our baja car so it makes a big U. and put a inline check valve in the tube. i think that this would work good

[J. Schmidt]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> ...run a vent hose from the tank or the filler neck up and around the main roll hoop like in our baja car so it makes a big U. </div></BLOCKQUOTE>
This is exactly what we've done in the past and the only issue with the judges was to make sure the vent opening pointed toward the ground so rain couldn't get in and any excess from the check valve would settle in the hose. Make sure to bring cutters and extra cable ties to the tech inspection so you can make adjustments right there if needed.

[shiv]

thanks nihal, we have fabricated the tank and it is trapizoidal in shape with a capacity of 7 ltrs.... we r using a in tank pump... plz give us more inputs .thanks once again

[Nihal]

The thing to watch out with in tank pumps is that when low on fuel they may overheat. They use the fuel to cool themselves. I've heard of a few teams having an issue with it, but I am not sure how common of a failure it is.

[Tony K]

Also, when you spec. the fuel line between the fuel pump and tank pass-through connector, be sure that it is rated for fuel contact on the inside AND outside of the hose. Asking the guy at the local speed shop if it's good for fuel on both sides isn't really the best idea... long story short, Aeroquip AQP Socketless hose has an outside cover that dissolves in fuel after a year or so, so I'd suggest something else.

[packtim]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by shiv:
thanks nihal, we have fabricated the tank and it is trapizoidal in shape with a capacity of 7 ltrs.... we r using a in tank pump... plz give us more inputs .thanks once again </div></BLOCKQUOTE>

Just think about this, you have designed a 7 litre fuel tank. However, you havent considered in this the volume the tank pump and the baffling inside it.

I think you need to go away and do some concept designs of it etc and weigh up your best options

[Frank]

make a "fuel tank / swirl pot" or "swank top"

ie, a fuel tank with a tapered / conical base that just won't starve

it does set the tank high, but simplifies everything, and ultimately saves real estate

i like foam inside, and an external pump

[Choon]

Anyone can share a piece of drawing about the fuel tank design? My university is preparing to join the competition for the first time, so i really need a lot of help from u guys...

thanks alot in advance

[Infinity]

What are the usual fuel consumption in the endurance event and in the worst case?? Generally what are the best and the worst performance in fuel economy of the SAE cars??

[Dr Claw]

speaking from experience, ANYTHING over 1.5 gallons is beyond disasterous, not just bad fuel economy. you get soo many penalties (4 minutes added to your endourance time, and a couple of other things happen too) if you use more than 1.51 gallons over the course of enodurance.

this includes if you've ran extra laps too on accident, say some circumstance stops you from entering on your last lap or driver error.

I'd recomned that you work backwards from 23.5km/1.51 gallons to find what is the worst possible fuel economy. 15.562 km/gal

[Biggy72]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dr Claw:
speaking from experience, ANYTHING over 1.5 gallons is beyond disasterous, not just bad fuel economy. you get soo many penalties (4 minutes added to your endourance time, and a couple of other things happen too) if you use more than 1.51 gallons over the course of enodurance. </div></BLOCKQUOTE>

We found this out first hand last year. We did really well in the endurance and could have been even faster had we not been with the slower group of cars, but we used 1.68 gallons and we were docked 4 minutes. This probably hurt us a little more than 10 positions in the overall standings.

[Dr Claw]

We burned 1.58 gallons on 23 laps in 2005.. Part driver error, and part track error - there was an accident arround the finish line on our last lap and we went arround once more since we couldnt get in. the track workers didnt register the crash with the extra lap, and we were penalized.

[Infinity]

Actually what i was looking forward was to consider what should be my fuel tank capacity so that the car doesnt fail out of fuel in any case. I admire you suggestions so i ll try to tune the engine well so that the fuel may be least consumed.

[Dr Claw]

1.8 gallons for racing then

as big a fuel tank as you can for testing/driver training/having fun!

make two, refueling sucks :X

[vandit]

hey nihal

what was the thing you mentioned about overheating in low fuel conditions ...i didnt understood...

[sandeep ganesh]

hey

gotta a doubt

we used a internal fuel pump attached to the top of the tank.During the event,the fuel leaked in gaps between the pump top surface and the tank.
My pump is attached to the tank and cannot be removed.the pump is attched by five nuts and bolts.Even though a rubber sleeve was provided,there was a leak.
what is the reason for the leak?
Is there any way i can make the pump detachable?[i couldnt weld the nut inside becoz the size of nut is very small]

[Chapo]

There probably is a way to make the pump detachable, but that is part of the challenge of FSAE working out how to do that for your self.

As for the pump leaking, I do not know what pump you are using specifically, but our pump (which is internal, but modified for a kind of internal external usage.) has a small check valve in it that opens when air is being pumped through the system so that its ingress into the fuel lines is minimised. This valve vents from the side of the fuel pump and if we had not accounted for it would splash small amounts of fuel out of the tank almost constantly.

Your fuel pump may have a similar valve causing you a problem.

Hope that helps

[sandeep ganesh]

thanks,
Also what sealant should be used to prevent fuel leak.[Becoz petrol reacts with some sealants].
Is it okay to use M seal to block the leak.Is there any sealant that dries quickly/settles quickly and prevents fuel leak?

[PabloH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by sandeep ganesh:
thanks,
Also what sealant should be used to prevent fuel leak.[Becoz petrol reacts with some sealants].
Is it okay to use M seal to block the leak.Is there any sealant that dries quickly/settles quickly and prevents fuel leak? </div></BLOCKQUOTE>

Super glue.

[Chapo]

Your best bet for finding an appropriate glue is to read the product data sheets. They will provide information on what the glue reacts to.

I suggest that you start looking at 2 part glues, we use an epoxy on ours. There are also a number of fuel tank repair kits that you can buy from service stations and auto stores that will work well.

[vkarmwar]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by J. Schmidt:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> do you guys use submersible pumps also? We had one last year on our car and the judges objected to it, saying they wanted an external one. They just let us make do cause changing the pump at the competition was not possible. </div></BLOCKQUOTE>
The rules don't state which type of pump to use. We've never had any problems with the internal
pump, except for running it dry accidently and needing to replace it (good thing it was cheep). There is a discussion here (http://fsae.com/eve/forums/a/tpc/f/125607348/m/7376081334/r/7376081334#7376081334) on internal versus external pumps. </div></BLOCKQUOTE>

can you please explain more what went wrong in running it "dry"..

[Drew Price]

In-tank pumps usually rely on the fuel to both cool and lubricate the pump. If you run it with just air going through, or without it completely submerged in fuel it can overheat, and eventually can fail.

[Warpspeed]

One trick with the fuel tank air vent is to loop it right around the outside of the tank a couple of times.
Even if your roll over valve leaks, the vent pipe will then form a liquid trap in any orientation.

[vkarmwar]

Hey guys...
WeAre an upcoming team from india...
so I wanted your help regarding what what material and thickness to use ina fuel tank...
Thanks....

[Jon Burford]

vkarwar
you pick, aluminium, steel, paper, wood, cheese.

[ppastorelli]

Hello everyone,

My name is Pedro, and I'm a member of team Formula CEM from UFSC Joinville in Brazil. We are building our second car this year and we have a question about the fuel tank (more precisely the path between the filler neck and the actual tank).
In order to facilitate manufacturing/accessibility/assembly, we were thinking of using something like in the photo attached. Filler neck in aluminum, a rubber hose (blue part) and the fuel tank in aluminum. We have seen stuff like this in random FSAE cars around "the internets" but we wanted to make sure it would be something legal by the rules.

722

Thanks in advance for any input!

[Jonny Rochester]

There does not seam to be anything wrong with your fuel tank design as pictured. The problems arise in the details, so if you show a more developed design I can comment further.

-the rubber hose and fuel cap needs to be the diameter as in the rules
-some rubber types can distort wildly when soaked in fuel
-there should be a vent from the fuel cap, a one-way valve type.
-a firewall should interrupt line-of-sight between the driver and the fuel cap