Generator runs on water? WTF??

[Circlotron]

Water injection is used to suppress detonation, so it permit higher boost pressures to be used.  The water itself doesn't add to the power output, in fact it reduces it since it is displacing fuel and air.

+1 for that.
Another reason injecting water into a naturally aspirated engine actually reduces power is that unlike when you heat air as the working fluid it expands and/or increases in pressure, a liquid, in this case water, needs a significant amount of energy to evaporate it without actually having raised the temperature. This is called latent heat of evaporation and it is energy effectively lost to the combustion cycle. Only when the water vapour later condenses in the outside atmosphere is the energy returned but that is way to late to be of any use. Water is basically bad news for a properly running naturally aspirated engine. It can help if fuel octane is too low or compression ratio is too high or engine is carboned up, but fix those things and it will run better than with adding water.

[Circlotron]

Having said the above, if the water droplets evaporate during the compression stroke thereby reducing the air temperature and consequently the amount of work needed to compress that air... Hmm.... Dunno. Although the energy needed to compress the air would normally be recouped on the expansion stroke, so maybe not.

[wiss]

Water injection is used to suppress detonation, so it permit higher boost pressures to be used.  The water itself doesn't add to the power output, in fact it reduces it since it is displacing fuel and air.

+1 for that.
Another reason injecting water into a naturally aspirated engine actually reduces power is that unlike when you heat air as the working fluid it expands and/or increases in pressure, a liquid, in this case water, needs a significant amount of energy to evaporate it without actually having raised the temperature. This is called latent heat of evaporation and it is energy effectively lost to the combustion cycle. Only when the water vapour later condenses in the outside atmosphere is the energy returned but that is way to late to be of any use. Water is basically bad news for a properly running naturally aspirated engine. It can help if fuel octane is too low or compression ratio is too high or engine is carboned up, but fix those things and it will run better than with adding water.

I guess that the proper solution in the air-plane case would be to double up size/number of engines, for some reason "they" don't want to do that They'd rather have 50% extra power for 200% more fuel consumption during take-off.

[free_electron]

i think that this thing producing energy is pure vapor (pun intended )

[Circlotron]

I guess that the proper solution in the air-plane case would be to double up size/number of engines, for some reason "they" don't want to do that They'd rather have 50% extra power for 200% more fuel consumption during take-off.

If the extra power is only needed for a very small percentage of flight time then the downside would appear to be acceptable. The alternative is the weight and cost of the extra engines that would be under-utliised for the vast majority of the time.

[IanB]

Having said the above, if the water droplets evaporate during the compression stroke thereby reducing the air temperature and consequently the amount of work needed to compress that air... Hmm.... Dunno. Although the energy needed to compress the air would normally be recouped on the expansion stroke, so maybe not.

You can get more power out of an engine at lower air temperatures because the air intake density is greater, meaning you can get a larger mass of air into the cylinder with each intake stroke, meaning you can burn more fuel in the power stroke (more oxygen present), meaning more power.

Now, suppose you cool the intake air by injecting water and letting it evaporate. The evaporated water will have a molecular weight of 18, which is somewhat lower than the molecular weight of nitrogen (28) or oxygen (32). So the water-laden air will have a lower density than dry air, and on top of that the water vapor will displace some of the oxygen in the charge (so the air will no longer contain 21% oxygen as normal, it will contain rather less). It follows that for two reasons there will now be less oxygen in the intake charge (lower air density, displaced oxygen), countering the desired effect of a lower intake temperature (higher air density). I haven't done the calculations, but my intuition says power will go down if you try this.

On the other hand, suppose you inject water droplets and don't allow them to evaporate before reaching the cylinder. This time no significant amount of air will be displaced, so no oxygen starvation will occur. On the other hand, the liquid water will evaporate in the cylinder with the combustion heat and increase the expansion power of the hot gases (making the internal combustion engine a kind of hybrid steam engine). In this case it may be that the power could be increased, though again I have not worked through the thermodynamic analysis to put numbers on it. Presumably if it was a viable proposition there would be water injectors in every car engine, and there are not...

[wiss]

Presumably if it was a viable proposition there would be water injectors in every car engine, and there are not...

It will become a major problem if the temperature drops below 0 degC.

[BradC]

An alternative to water is methadone.

or just use windshield washing fluid which contains Methamphetamines as an anti-freeze agent. 

Those have got to be the best pair of autocorrect mistakes I've seen in a long time. I assume both of those were suppose to read Methanol.

[timb]

An alternative to water is methadone.

or just use windshield washing fluid which contains Methamphetamines as an anti-freeze agent. 

Those have got to be the best pair of autocorrect mistakes I've seen in a long time. I assume both of those were suppose to read Methanol.

Haha, shiiiit. Yes, methanol was what I was after. Damn you iOS8!


Sent from my Smartphone

[timb]

Presumably if it was a viable proposition there would be water injectors in every car engine, and there are not...

It will become a major problem if the temperature drops below 0 degC.

Also you'd have to keep a huge tank of water in your car, which weighs it down, reducing gas mileage and nulling the benefits.


Sent from my Smartphone

[Circlotron]

On the other hand, the liquid water will evaporate in the cylinder with the combustion heat and increase the expansion power of the hot gases

The Pressure-Volume-Temperature equation has to balance, so substitution of water vapour for air in part of full won't make any real difference to the expansion power. What will make a difference is the energy absorbed from the hot gases to turn that liquid water into vapour.

As a test, suppose you have a container of hot high pressure air. Squirt a small amount of water into it and it instantly turns to vapour. Does the pressure increase or decrease? If it increases you have an (almost) free energy machine. What definitely *will* happen is the injected water evaporating causes the overall temperature to drop. Almost certainly that will cause a pressure drop, the opposite of what you want.

[SeanB]

You do know the new Euro spec diesel cars ( with the blue efficiency labels) have a special tank in them, containing a very expensive to buy ( but so cheap to synthesise with a standard Haber process plant) concentrated urea. Most of the cost is in the fancy bottle and the blue dye added to make it look impressive, while it is just concentrated urea like what you have to unload every morning. It serves no function in the engine, just used to clean the exhaust of nitrogen oxides, and it only works when the engine is warm, so most of the time it is no use.

[SirNick]

A happy synergy on long car trips though.

[timb]

You do know the new Euro spec diesel cars ( with the blue efficiency labels) have a special tank in them, containing a very expensive to buy ( but so cheap to synthesise with a standard Haber process plant) concentrated urea. Most of the cost is in the fancy bottle and the blue dye added to make it look impressive, while it is just concentrated urea like what you have to unload every morning. It serves no function in the engine, just used to clean the exhaust of nitrogen oxides, and it only works when the engine is warm, so most of the time it is no use.

Now if we could only easily power cars from methane, we could drive non-stop forever thanks to drive-thru Taco Bells and Big Gulps!


Sent from my Smartphone

[SirNick]

Taco Bell:  Where every meal is a #2.

[Circlotron]

As a test, suppose you have a container of hot high pressure air. Squirt a small amount of water into it and it instantly turns to vapour. Does the pressure increase or decrease? If it increases you have an (almost) free energy machine. What definitely *will* happen is the injected water evaporating causes the overall temperature to drop. Almost certainly that will cause a pressure drop, the opposite of what you want.

If you set up a Diesel engine to inject water instead of fuel oil this would be an identical situation. I strongly suspect it doesn't produce worthwhile results.

[Phaedrus]

I guess that the proper solution in the air-plane case would be to double up size/number of engines, for some reason "they" don't want to do that They'd rather have 50% extra power for 200% more fuel consumption during take-off.

Yes, but keep in mind that weight is a huge deal in aircraft design. A (more realistic) 20% power boost with poor fuel efficiency when you need it is a much better solution for something like a fighter, or a plane that needs an extra boost on take-off, vs. adding hundreds of kg or more of weight in additional engines. Not to mention the mechanical complexity of the latter solution, as well as aerodynamic compromises that would have to be made.

EDIT: Also, WEP stands for "War Emergency Power", not water. WEP was the term for any throttle setting above 100%. On some planes this just meant running the engine above its rated RPM, on others it involved water or methanol injection. Some planes like later versions of the Messerschmidt Bf 109 had two or three WEP settings, involving different performance boosting methods. Pushing a plane into WEP usually meant pushing the throttle hard enough to break a wire blocking off the higher setting. This way the mechanics would know if WEP was used, and could perform the necessary additional maintenance checks.

[dave_j_fan]

i suggest mini generator
pour cold water on a rat ...he will vibrate ..
put piezo sensors/magnetdrive to get electric power 

[NiHaoMike]

As a test, suppose you have a container of hot high pressure air. Squirt a small amount of water into it and it instantly turns to vapour. Does the pressure increase or decrease? If it increases you have an (almost) free energy machine. What definitely *will* happen is the injected water evaporating causes the overall temperature to drop. Almost certainly that will cause a pressure drop, the opposite of what you want.

That's part of the point. Running leaner air/fuel mixtures boosts engine efficiency (up to a point), but a very lean mixture would quickly cause the engine to overheat. Adding water injection cools it down to acceptable levels.

[mswhin63]

I wonder if anyone on the forum lives nearby to verify the claim and maybe inform the forum what they are scamming.

[miguelvp]

I wonder if anyone on the forum lives nearby to verify the claim and maybe inform the forum what they are scamming.

No need, they are scamming. What they others are talking about is not even about the OP anymore

[Kevman]

You do know the new Euro spec diesel cars ( with the blue efficiency labels) have a special tank in them, containing a very expensive to buy ( but so cheap to synthesise with a standard Haber process plant) concentrated urea. Most of the cost is in the fancy bottle and the blue dye added to make it look impressive, while it is just concentrated urea like what you have to unload every morning. It serves no function in the engine, just used to clean the exhaust of nitrogen oxides, and it only works when the engine is warm, so most of the time it is no use.

Been common in the US for years on diesels. Diesel vehicle reliability took a nose dive in 2003 in the US because of manufacturer's struggling to meet pollution laws- a 2003 diesel F250 is worth more than a 2005 for that reason. Its just now getting back on track...

You guys are talking about methanol injection, which just limits combustion chamber temps to inhibit detonation. For efficiency uses, there are 6 cycle engines- which inject water and work like a steam engine after the exhaust stroke. I don't know of any currently in production, though.

[Circlotron]

There are no 6-cycle engines in production because they don't work. See posts 61 and 66.
The Crower engine for example has a conventional expansion stroke but then instead of then opening the exhaust valve it re-compresses the expanded gases and at the top of the next stroke injects water, hoping for another power stroke. The thing is, the energy you receive from the first expansion stroke is almost totally expended by re-compressing these hot gases. And then injecting water into the hot gases at the top of the stroke doesn't work for the same reason you can't run a Diesel engine on water - doing so absorbs heat, it doesn't liberate heat.