Would this work?

[ozkat]

Here goes. First of all this would only be for dragracing.
A turbo forces more air into a engine and combined with more fuel produces a bigger bang... more HP.
Nitrous Oxide injection does a similar thing by chemicaly introducing more oxygen to the engine, combined with the extra fuel creates a bigger bang.... more HP.
Now here is the question.
If you were to use compressed air/compressed oxygen, in a cylinder similar to a scuba or oxy welding cylinder that can maintain very high psi, then regulate the exiting air/oxygen to say 35 psi, then using secondry regulators linked to a gear shift sensor, so you can regulate the psi for the chosen gear selected. Say 6psi 1st gear, 10psi 2nd gear, 18psi 3rd gear, 25psi 4th gear, 30psi 5th gear. Also you could regulate the psi to only operate at wide open throttle, so as soon as you back off psi is reduced to nothing. Using a rising rate fuel pressure regulator would solve fueling issues in theory. You may say that the cylinder required would have to be to large but very small tanks are available these days that hold an extreemly large amount of compressed air/oxygen, more than enough for a few passes. Am i nuts or does this sort of system have any merits for drag racing?
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[Large]

I would have thought someone would be doing it already if it worked

[Large]

And don't they use NOS because it's 2 "O" atoms per molecule?

Whereas "O" is just one O?

[ozkat]

Turbos only use 1 "O" as well. All i was thinking was you would have a turbo system with virtually no moving parts, no oil supply issues and a very controlable system.

[sharky]

What are the class rules like here for bikes ? Obviously you wouldn't be 'normally aspirated' so wouldn't it put you up against the full on turbo/nitrous boys ?

[Deano]

if you worked out how much air your would need to supply i think you will be surprised at how huge the tank would be.

the theroy behind it all sounds doable but i think the tank will be the issue. and the equipment needed to compress the air to the massive pressure required wouldn't be cheap.

you could always go to your local BOC agent and see if you can buy a bottle of oxygen and give it a go

are you allowed to tow a trailer at the drags?

[zx12argh]

I had a simliar idea for a type of at need supercharger... Have a compressor link to the engine that pumps the cylinder when you are just cruising and then at the flick of a switch you get a boosted engine.

The only thing I can think of is that you would need to calc volume air needed for the application required (litres per pass) to determine the size of tank required at given PSI (kPa why the fudge is everything still in imperial) and set everything up like a supercharger setup. It would be like have a blower but with out the need for belts running everwhere and possibly stealth installed.

[Large]

quote:Originally posted by ozkat

Turbos only use 1 "O" as well. All i was thinking was you would have a turbo system with virtually no moving parts, no oil supply issues and a very controlable system.


Goooogle is your friend :)

In racing, nitrous is injected into an automobile's air intake to increase power. This isn't magic -- basically it is just providing more oxygen which allows more fuel to burn per stroke. The extra fuel per stroke gives you the extra power -- the nitrous just provides the oxygen needed to burn that fuel. It also provides a cooling effect as it transitions from a liquid (in the bottle under pressure) to a gas -- this helps offset the additional heat of burning more fuel.

There is an oxygen atom per molecule of nitrous (N2O) -- 33% versus 21% in regular air (which is also mostly nitrogen). Nitric Oxide (NO) would be better (with 50% oxygen), but that molecule is much more tightly bound. N2O falls apart at 572 degrees F.

O2 gas would theoretically be better, but you'd need a much thicker (heavier) tank to obtain the higher pressure needed to keep it liquid. Also it'd be much more of a hazard in a crash, line break, etc. Boom.

[zx12argh]

After a rough calc you'd use about 200 litres of air per pass - so run the bike on 14 psi boost you'd need a tank with 3000 psi. I standard scuba tank can hold 3500psi...

If you recharged the tank every pass if may work tho you would add a bit of weight...

[derangedrover]

Your biggest issue is going to be flowing the required volume, and in a controlled manner, ie regulated. Another problem is going to be finding a lightweight cylinder that will reliably handle the stresses of the near instant releases of pressure. There are some composite (carbon/kevlar that doesn't work harden) scuba and lpg tanks that might fit the bill.
Go outside and knock the regulator off a full scuba or whatever chosen cylinder and time how long it takes to empty, probably longer than you want....and thats at absolute free flow condition with no restrictions like a regulator. It will probably drop cylinder pressure so fast you wont be able to flow the required volume for any period of time...

Cheers
Daryl

[derangedrover]

Did some math for fun.

A 1000cc (61 cu in) engine spinning @ 10,000 rpm will consume 150 cfm. @ 85% volumetric efficiency.

cfm = .85 x 61 x 10000/3456

= 150 cubic feet per minute

A 'C' size cylinder (11" long, 4.4" dia) charged to ~3000psi with compressed air (as a gas) will contain 9 cubic feet of air, or 255 liters. This is enough volume to theoretically supply the engine for ~10 seconds.
So if you can sort a delivery system to handle the flow rates achieve the positive manifold pressure like you describe, it might be possible.
Don't forget N2o works because its not only an oxidizing agent, but also supplys the Nitrogen atom which is the non consumed particle in the combustion process that is superheated and expands causing the rising cylinder pressure, ie the power stroke.

Another source for a cylinder might be personal oxygen systems for medical purposes etc, smaller sizes and usually lightweight, but made of aluminium usually, which probably wont like the sudden depressurisation required for your idea to work, neck size might not support the flow rate either.

This might all be pure bullshit, but I had some fun thinking about it.

I once tried to 'submarineise' a small diesel 4wd by strapping the workshop compressor on the tray and plumbing a 3/4" hose straight into a plate that was bolted over the intake manifold. Couldn't get it to run above 1500 rpm and it emptied the ~400lt water content tank, charged to 300 psi and regulated by a ball valve, in under a minute. Had much more success using it to spool up the turbo by plumbing the airline into the exhaust housing, good for off idle boost :)

Cheers
Daryl

[Slain]

weight is no drama, the carbon wrapped cylinders we use at work weigh bugger all

[shift1313]

I see this has already been answered but i would say there is no way this could happen. the calcs look right but that cfm number seems awful low to me. my 4cyl 2.6l car will flow 180cfm at 6000rpm per cylinder. on a flow bench anyway, i dont know if that is swaying my perspective.

but as it has been said there are alot of obstacles to overcome. I think you would be better off trying to get an electric turbocharger fitted on your bike. 1 fan can produce 2psi and can be mounted in series. Low boost means minimal modifications. Even if you could theoretically get the numbers worked out i dont think you are ever going to get the volume flow rate you need coming out of a cylinder. That pesky bernoullis equation which lets you calculate without considering frictional losses.

another issue that would pop up here in the states is legality. They dont let just anything on the tracks here. There had better be some sort of DOT stamp on whatever cylinder made it on a bike.


more power too you if you can get it to work but i think you would need a sub 500cc motor to even make it feasable.