OT -Save upto 50% on fuel costs - snake oil

[ARWadsworth]

spotted this in the local rag.

So how does this one not work?

[Huge]

It electrolyses water and burns the gases as fuel.

The flaw is that they ignore the energy required to electrolyse the water. They talk about "fuel cells", but they are no such thing.

[Jim White]

Electrickery

[ARWadsworth]

for that link. That newspaper is in the right area for the advert.

It did allow me to find.

[Tim Streater]

Exactly. Of course, it "works", but so what. The only question of interest is does it reduce consumption, and tests show it does not.

[dom]

Works perfectly.

In as far as the seller is making money.

And might help some of the dupes realise that learning about science in school is important.

[Skipweasel]

Oh, it works really well. The bloke selling it gets your money just dandy.

[Skipweasel]

Damn - rip-off-rays!

[dennis]

> Thanks for that link. That newspaper is in the right area for the advert. >

If they were done correctly the fuel consumption would be worse than without the device. It takes energy to split the water and when its burnt you get the energy back. However the conversion at both stages wastes energy as heat so you get far less useful energy back than you used to make the hydrogen and oxygen. Of course the wasted energy may have been too small to measure as it is at best the maximum output of the alternator and probably far less. There is a whole group of nuts^Wpeople on the internet running water fuelled cars, all of which are wrong and/or liars.

[Andy Champ]

A small amount of water injected into the engine can improve power output and efficiency - it acts as an anti-knock agent, cools the charge, and can have other _minor_ benefits mostly under heavy load.

But this device? Snake oil it is.

Andy

[ARWadsworth]

>>> Thanks for that link. That newspaper is in the right area for the

Which tests are you refering to?

Well that is a nice piece of English.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "ARWadsworth" saying something like:

If there was anything to it at all, the carmakers would be fitting them and claiming tremendous improvements, doncha think?

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Skipweasel saying something like:

Like X-Ray specs, in all the comics years ago. Just what's needed in a girls' dressing room.

[ARWadsworth]

Indeed, hence the question "So how does this one not work?"

[John Williamson]

There *might* be a slight improvement in combustion efficiency by adding hydrogen to the fuel/air mix. Nowhere near doubling, though.

The problem with the claims that these systems make is that to make the hydrogen to burn, they use an electrolytic process, which uses power from the alternator to split the water into hydrogen and oxygen. This takes marginally more energy than can be gained from burning the hydrogen with air to make water again. Assuming the splitter is 100% efficient, which it isn't, the normal car alternator is less than 50% efficient, so to get a kilowatt hour of energy's worth of hydrogen, it takes at least two kilowatt hours' worth of energy to turn the alternator. This energy can only come from the car engine, by burning extra fuel. As the average car engine is less than 25% efficient, you'd be burning eight kilowatt hours worth of fuel to get one kilowatt hour's wirth of hydrogen.

If the process worked as claimed, you could use the energy generated by burning the hydrogen to turn a generator, which would generate enough hydrogen to turn the generator, but that would be perpetual motion....

Under high load conditions, as has been said already, a slight improvement in engine efficiency can be got by injecting water into the cyinder, which turns into steam, and gives a smoother power delivery, while extracting more energy from the compustion process, and reducing certain types of pollution. The makers don't do it, because the cost of the added complexity isn't paid back over the life of the vehicle.

[Skipweasel]

That's not to say that water injection doesn't work - it does, though in most cases the savings are minimal. But splitting water and burning the results - that's silly.

[dennis]

But there is little actual evidence that even this is true. Most if the evidence is "well it runs better in the fog" comments.

[Andy Champ]

Read

the talk page too BTW...

Andy

[dennis]

So if you modify the engine it may stop it blowing up if you can get high octane fuel. It doesn't increase the power of an engine though.

As an aside to the wiki, the harrier jump jet can only hover when it has water to inject into the engine, without the water the engine burns out at full power. IIRC they carry enough water to hover for about 90 seconds (a few hundred litres). AFAIK the water plays no part in increasing the power and probably makes it less efficient.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "dennis@home" saying something like:

Or turbo boost. Water injection simply extends the envelope.

In effect, it does, if not absolutely.