Oxygen concentrator sound level

[rbowman]

It's easy enough to destroy your engine and drivetrain with nitrous without getting that exotic.

[rbowman]

And might consume as much power as it produced.

[rbowman]

I imagine somebody tried it and found it wanting.

Hey, if it works in a Titan II rocket it ought to work in a fuelie. Or maybe they were emulating a Me-163. Hydrazine, methanol, and 80% hydrogen peroxide. What's not to like?

My physics TA was a drag racing fan. He liked to point out the textbook illustration of the maximum coefficient of friction and linear acceleration was getting bent at the strip. He also mentioned that if you were trying to adjust the CG on a commercial airliner depleted uranium was just the stuff.

Another good reason not to fly.

[Mike Duffy]

Might? I decided to perform a simple first order estimation:

From

get some basic specs on the concentrator:

4.1 Kg, 2 litres/min O2 produced, 120 W power consumed. (Also specified is O2 concentration 87% to 96%; I use 91% for calculation below marked with "&".)

From

we get (for a 1600 cc engine) the relation of 54 cubic feet per minute of normal air to make 78 horsepower.

First, we figure out how many of the O2 concentrators we need:

54 cubic feet per minute = 1530 litres / min. If one O2 concentrator produces 2 litres / min, we need the equivalent of 765 O2 concentrators.

These (or one big one) will weigh in at 3.1 metric tons (4.1 kg * 765), and require 120 W * 765 = 92 Kw = 122 hp.

The power from the engine though, is 5 * 78 hp * 0.91 (&) = 335 hp. (The factor of 5 is the gain from using pure oxygen instead of air). But we need to subtract the 122 hp used by the concentrator, thus 233 hp. Effective 'gain' is 233 / 78 = 3.0

From

We get an entry for a 1600 cc engine:

VW flat-4 Type 1 250 1600cc dual port

I have no idea of the actual power rating of this engine; I am only interested in the weight of 250 Kg.

So the entire contraption (concentrator + engine) ends up wighing 3.35 metric tons (3.1 + 0.25).

Total power available to wheels is increased by a factor of 3. Total weight is increased by a factor of 13.5

So on first glance, probably it won't work. But then again, one big concentrator should be more efficient than 765 small ones. If it could be made 4 or 5 times more efficient (13.5 / 3), we reach the break-even point.

Then, we need to work out how not to burn holes through the engine head.

[invalid unparseable]

Good analysis. I am also reminded of a Scotty Kilmer video reminding that if you turbocharge an engine you must remember they you need a beefed up drive train to adequately handle the extra power.

[rbowman]

One of the down ticks for the Toyota 86/Subaru BRZ is the 2 liter engine. When asked why they don't turbocharge it Toyota answers it is well balanced as it is and more power would mean a redesign. Even the tuners say any engine work will need a beefier clutch.

i wonder what the current trend towards smaller engines with boost will mean in longevity. It's not like a few decades ago when cars were over-engineered.

[invalid unparseable]

Did a quick google on this and engines are apparently OK for longevity but adding more parts like the turbocharger means more stuff that might break down.

[Ralph Mowery]

For common on the road usage I have always though the turbocharges and such was just more stuff to cause trouble. Just make the engine larger.

I can see them for race cars where you want max performace for minimum weight and plan on rebuilding them after almost every race.

[invalid unparseable]

Some people like those jackrabbit starts but not for me. Car and Driver may not like my non-turbo Subaru but Consumer Reports loves it.

[trader_4]

I think the advantage is that the turbo is there to boost power when needed, but when not, the smaller engine gets better fuel economy. If you put a larger engine in to get the peak power, it would burn more fuel even at lower power output. And apparently reliability isn't that much of an issue. They are essentially two fans on a shaft and should last the life of the engine.