crazy thought of tday: stored boost for instant HP

[sammyg2]

With the emphasis today on hybrids .... small efficient turbo engines etc a thought just popped into my head:
stored boost.

Suppose we had a small compressor that built up presure in an air tank and that pressure was released into the intake manifold on demand, = instant (and temporary) boost.

Why? it could be charged while iding, while decellerating, with significantly less detrimental parasitic losses than a conventional supercharged or turbo engine.

Heck why not take it another step, have one or two cylinders switch from internal combustion to air compression on decell, like a jake brake or such. It'd help with braking and take that energy and sasve it instead of turning into heat.

Wouldn't do much for constant cruise but would be nice for stop and go driving.

'spose it could build up 15 or 20 psig in a 10 gallon tank, maybe that's too big for packaging but we'll go with it for 'sposes.

On a small 1.6 liter engine that could produce a 5 psi boost under accelleration for what, 10 seconds maybe longer? Haven't done the math here, so just guessing so far. Who doesn't want an extra 50 hp once in a while, and if it's basically free with ZERO lag ....

We don't need much power on steady cruise or gradual accelleration, just on innitial start up to 30 or 40 mpg, that would allow a much smaller engine to push around a bigger vehicle.

Yes it'd be fairly complex, prolly more than I could pull off in my garage with all the computerized stuff, but the big car makers could do something like that in their sleep.

Oh well, just a thought.

[stomachmonkey]

Sorta like NOX without the NOX?

[1990C4S]

I suspect you would need a significant reservoir to assist a turbo.

And since you reduce efficiency it's a non-starter.

[sammyg2]

Originally Posted by 1990C4S

I suspect you would need a significant reservoir to assist a turbo.

And since you reduce efficiency it's a non-starter.

please elaborate.

[aschen]

I think your guess for volume and pressure of air required are off by an order of magnitude or 2

The math is straight forward to do a back of envelope calc however. For reference an engine will be sucking 10 lbs of air per min at 100 HP.

A 10 gal tank at 1 ATM over ATM (2 ATM absolute) will be holding .2 lbs of air and will only be able to maintain 5 psi boost for a small fraction of even that tiny mass

[Porsche-O-Phile]

Interesting idea... I'm guessing the weight of a tank / distribution system would more than negate any gain. If you went with REALLY high stored pressures maybe, but then there are potential safety / liability issues, etc.

Maybe a 10 ft^3 tank at... I dunno... 300 psi? Maybe higher? That bled off to provide +/- 1 or 2 atmospheres of boost would probably last a while.

[widebody911]

So like an E-Ram?

[gwood]

Why only 300 psi? I have an air rifle and a hand pump that uses 3000 psi, so the techs not that exotic.

[MBAtarga]

Make sure to wrap it with a cool collar!

[aschen]

Composite tanks go to about 5kpsi with conventional construction.

Again I think you will find practcally speaking you won't be able to store enough air to make the concept worthwhile

[John Rogers]

Years ago a Porsche nut in San Diego, had Mark Kinninger at Black Forest build him up a twin turbo 4L monster with some sort of electrical boost storage system and tanks so there was instantaneous power with very poor control and gas millage but hey it is only $$$$$$. They did some work on it at the guy's rice rocket shop and FORGOT to hook back up the boost limiter power to the electric pop off valves! It went "really fast" according to the owner till the engine actually blew two cylinders and heads off one side and fractured the case so it looked like a mosaic piece of fine art. Mark figured probably 20 bar of boost to do that??!! So I guess it would work.........

[DanielDudley]

You would have to put in a check valve, and once on boost, you would have to use the tank for 100 % of the total volume. Many engines will flow at over 600CFM at WOT and max RPMS.

[Flieger]

Audi tried to use a compressed air storage system on their LMP1 car but it got banned after testing.

There is a car that runs on compressed air being made but it's not a hybrid.

There are hybrid systems for busses that use hydraulic accumulators and motors instead of batteries.

I think rather than turn it into an air motor it is more efficient to use a separate hydraulic motor.

[manbridge 74]

Backyard Billy that sh-eet!

[Por_sha911]

Bah. Been there done that. VW had a compressed air storage system...oh wait...it was the spare tire to run the wipers.

Never mind.

[wdfifteen]

You could store the energy as electricity and have an electric supercharger for the extra hp. You can't store a lot of energy in a car-size volume of compressed air.

[wdfifteen]

Originally Posted by Por_sha911

Bah. Been there done that. VW had a compressed air storage system...oh wait...it was the spare tire to run the wipers.

Never mind.

Wasn't it was for windshield WASHER?

[pcardude]

When I was a kid I rigged up a small tank to my 5hp mini bike. The pressure regulator wasn't fast enough to maintain boost psi. It wouldn't flow enough when I revved the motor up and the tank emptyed really fast.

Then I put a propane tank on it and just opened the valve which didn't make it go any faster. Which was a bummer.

[Gogar]

Sounds kind of cool!

I've also heard of a concept where they convert the physical energy from braking into electricity, and store it in a battery. Then they place electric motors at each wheel and utilize them for instant torque that even the best turbocharger would have trouble replicating.

Sounds a bit far off, though. Definitely not as cool as the turbo idea!

[Bill Douglas]

Good idea. We'll call it Can of Boost, pronounced Can-a-boost.