The Global Economic Crisis...

[Ragnarok]

they can raise the price as high as they want.

Wrong. If one company pushes it's prices up, people will stop buying from them.
The prices have to rise in unison between the companies.

u got no choice but to pay.

Again, wrong. I've just made a 21 mile journey without paying petrol companies one penny.

1.5 liter engine, by nature, sucks down 2,250 liters of fuel/air mixture @ 3,000 RPMs

That would only be if you've got your foot welded to the floor.

Taking a number I have handy, a 206 GTi 180 with a 2 litre engine takes about 2.5 hp to overcome air resistance at 30 mph.
The car has 180 hp in the first place, so you're only using, if you consider that some energy is needed to overcome mechanical friction and to keep the engine turning over... maybe 5% of the car's potential power.

More likely, the car would be using a couple of hundred litres a minute, not thousands. But there's simply not enough gasses handy even then.

[ramses]

This will sound odd, but I think a HHO system could provide a little fuel benefit. Your engine should use the same amount of gas at a given RPM whether it is dragging 500lbs up a hill, or coasting along on the freeway. Picture this: you are pumping a bike pump at 1 stroke/second with nothing an open output. you then choke down the output, but still make 1 stroke/second, displacing the same amount of air, it's just harder.

when you are sitting at idle at a light, why not use the 800RPM's worth of gas to do something? granted your automatic transmission would, while accelerating, have you change gears at a higher RPM than without, thereby RAPEING your fuel efficiency. also a net loss would be expected due to the extra weight provided by the HHO system and the associated energy required to be at a given speed. this means more dissipated as heat on braking.

If I am wrong, please correct me nicely.

[jackssmirkingrevenge]

when you are sitting at idle at a light, why not use the 800RPM's worth of gas to do something?

Interesting point but the way I see it, since we've established that you can't get more energy than you put in, this means that your engine will waste more fuel running the alternator but not get the same benefit from the HHO generated, therefore it seems that this would not work in practice.

I suppose you could always put a turbine in your tailpipe hooked up to a generator to charge a battery, if you want to put wasted energy to use.

[jrrdw]

Stay on topic! There is a automotive section over at www.theopia.com USE IT!

[Ragnarok]

Stay on topic! There is a automotive section over at www.theopia.com USE IT!

Actually, this sort of is the topic. It's about the global economic crisis, and fuel costs and the corresponding HHO scams are part of that.

@JSR: That is actually a viable option. That's much the same as Turbochargers do, but if instead of providing extra boost pressure, you could use it for other things.

However, Turbos only really kick in if you're being fuel inefficient in the first place - lots of revving, etc.

[jrrdw]

Your splitting hairs Ragnarok, stop it.