Not a Mr. Fusion, But Somehow Better
March 3, 2011 2:32 PM Subscribe
I recently saw a video where an inventor claimed to power his car with water. He claimed that he extracted hydrogen and oxygen via electrolysis and then used those gases to power the car. Is this too good to be true? (It seems so simple that if it worked it would be everywhere.)
My first thought is that the fuel can't possibly generate enough energy to make more fuel.
The company has filed some patents over the technology.
If this is hokey, how far is it from reality? What efficiencies or changes would need to happen?
My first thought is that the fuel can't possibly generate enough energy to make more fuel.
The company has filed some patents over the technology.
If this is hokey, how far is it from reality? What efficiencies or changes would need to happen?
At the very least, it is a somewhat terrible idea in that hydrogen and oxygen are both extremely flammable.
posted by maryr at 2:35 PM on March 3, 2011 [1 favorite]
posted by maryr at 2:35 PM on March 3, 2011 [1 favorite]
mr_roboto beat me to the punch. If the process to convert water to hydrogen and oxygen could even provide enough energy to be self-sustaining, it would defeat physics. There's no way it also would have enough energy left over to power a car.
posted by mikeh at 2:35 PM on March 3, 2011
posted by mikeh at 2:35 PM on March 3, 2011
Yes, it is too good to be true. First law of thermodynamics: conservation of energy. Electrolysis requires electricity (i.e., energy) to work. The amount of energy required to split the water in the first place is exactly as much energy as you get from recombining the gases and generating water. Then the second law of thermodynamics says you can't use 100% of the energy you get out of the recombination (a bit of oversimplification, but it will do here) so you lose energy in the process.
posted by DevilsAdvocate at 2:37 PM on March 3, 2011 [1 favorite]
posted by DevilsAdvocate at 2:37 PM on March 3, 2011 [1 favorite]
He isn't powering his car with water. He is powering his car with the energy which had to be expended to disassociate the water into hydrogen gas and oxygen gas.
It isn't too good to be true. But it also isn't very good. Where does that energy come from? In the US, the most likely answer is "From burning coal in an electricity generation plant".
posted by Chocolate Pickle at 2:37 PM on March 3, 2011
It isn't too good to be true. But it also isn't very good. Where does that energy come from? In the US, the most likely answer is "From burning coal in an electricity generation plant".
posted by Chocolate Pickle at 2:37 PM on March 3, 2011
OK; looking at what he's actually doing on the website, it seems that he's adding oxygen and hydrogen to diesel. So the car is still running on a standard petroleum fuel, but this fuel is being used to electrolyze water and the resulting hydrogen/oxygen mixture is then mixed in with the standard petroleum fuel.
I highly doubt this would increase the overall efficiency of the engine, and it seems like it comes with major corrosion risks.
posted by mr_roboto at 2:38 PM on March 3, 2011
I highly doubt this would increase the overall efficiency of the engine, and it seems like it comes with major corrosion risks.
posted by mr_roboto at 2:38 PM on March 3, 2011
If it were somehow possible to beat the pesky physics laws on the electrolysis front then my guess is that the sort of plant which could accomplish this first would probably not be of a size suitable for lugging about in a car: efficient power generation is easier to do on a large scale (and it you could do this then you could just use the energy to power an electric car).
posted by rongorongo at 2:39 PM on March 3, 2011
posted by rongorongo at 2:39 PM on March 3, 2011
(Oxygen is really corrosive, as is the water that results from buring hydrogen).
posted by mr_roboto at 2:40 PM on March 3, 2011
posted by mr_roboto at 2:40 PM on March 3, 2011
At the very least, it is a somewhat terrible idea in that hydrogen and oxygen are both extremely flammable.
It's an issue to be kept in mind in the design of the car, but not an insurmountable or inherently terrible one. There are already vehicles which run on propane — a flammable gas at ordinary temperatures and pressures — without excessive safety problems. You'd probably be better off just venting the oxygen from the electrolysis, and then taking in oxygen from the atmosphere when you wanted to burn the hydrogen, instead of keeping pure oxygen around, though.
posted by DevilsAdvocate at 2:43 PM on March 3, 2011
It's an issue to be kept in mind in the design of the car, but not an insurmountable or inherently terrible one. There are already vehicles which run on propane — a flammable gas at ordinary temperatures and pressures — without excessive safety problems. You'd probably be better off just venting the oxygen from the electrolysis, and then taking in oxygen from the atmosphere when you wanted to burn the hydrogen, instead of keeping pure oxygen around, though.
posted by DevilsAdvocate at 2:43 PM on March 3, 2011
The amount of energy required to split the water in the first place is exactly as much energy as you get from recombining the gases and generating water
Actually, it takes more energy to break a water bond. See here. Water's pretty darn stable, which is part of why there's so much of it around rather than low-energy reactions constantly breaking it up and mixing it into other things.
posted by AzraelBrown at 2:53 PM on March 3, 2011
Actually, it takes more energy to break a water bond. See here. Water's pretty darn stable, which is part of why there's so much of it around rather than low-energy reactions constantly breaking it up and mixing it into other things.
posted by AzraelBrown at 2:53 PM on March 3, 2011
I think you're misreading me, AzraelBrown. If you're saying that it takes more energy to break an H-O bond in water than is generated in forming an H-H bond in elemental hydrogen, that's true, but I'm talking about the entire cycle: water -> hydrogen & oxygen -> water. The energy required to electrolyse one mole of water (H2O -> H2 + ½O2) is exactly the amount of energy released by burning one mole of hydrogen (H2 + ½O2 -> H2O) [if the water is at the same temperature, pressure, and state at the end as it was in the beginning.]
posted by DevilsAdvocate at 3:00 PM on March 3, 2011
posted by DevilsAdvocate at 3:00 PM on March 3, 2011
One other note on the original question:
The company has filed some patents over the technology.
This means nothing as far as whether the invention works as claimed. The USPTO considers whether an invention is new and non-obvious when deciding whether to grant a patent (and even on those issues they have been widely criticized for doing a poor job); whether it actually works is not something the USPTO, in practice, determines.
I always have a good chuckle when a late-night infomercial trumpets its product's patented technology, as if that's some measure of quality. The only thing the patent means is that you can't get it from anyone else. Not that it works.
posted by DevilsAdvocate at 3:12 PM on March 3, 2011 [1 favorite]
The company has filed some patents over the technology.
This means nothing as far as whether the invention works as claimed. The USPTO considers whether an invention is new and non-obvious when deciding whether to grant a patent (and even on those issues they have been widely criticized for doing a poor job); whether it actually works is not something the USPTO, in practice, determines.
I always have a good chuckle when a late-night infomercial trumpets its product's patented technology, as if that's some measure of quality. The only thing the patent means is that you can't get it from anyone else. Not that it works.
posted by DevilsAdvocate at 3:12 PM on March 3, 2011 [1 favorite]
I dreamed this up in 9th grade while riding the bus home, sketched it up, and then argued endlessly the next day with my science teacher about how it definitely can work and god why are you such an idiot for not understanding.
posted by spikeleemajortomdickandharryconnickjrmints at 3:15 PM on March 3, 2011 [2 favorites]
posted by spikeleemajortomdickandharryconnickjrmints at 3:15 PM on March 3, 2011 [2 favorites]
OP, most people above answered you question based on their own assumptions, not on what your link is talking about.
Everyone's entirely right that electrolysing and then burning hydrogen and water would waste more energy than you'd get out of it; it would have negative efficiency. But these guys aren't trying to "power a car with water", as you say in your question.
From the website: Aquygen® gas produced on-board a vehicle and introduced to the engine's combustion environment has demonstrated increased fuel economy as well as decreased vehicle emissions.
A regular internal combustion engine is not perfectly efficient. It cannot be perfectly efficient (see the Carnot Cycle). So what these guys are doing is trying to use hydrogen and oxygen gas to up the efficiency of your standard combustion engine by injecting the H2 and O2 into the gas tank. The idea being that the energy lost in electrolysis is made up for and then some in increased fuel efficiency. Kind of like how cars waste energy by braking, but hybrids take that wasted energy and put it back into the power train.
Who knows if this actually works. It won't be hard for people to test independently once the public gets their hands on the system. But it's not beyond the realm on the plausible. As far as I can see they aren't pretending to break the laws of thermodynamics, only to bring us a little bit closer to the efficiency limit.
[Please note that I'm not a chemical engineer, and have no idea what chemical process they think is happening between the gas, hydrogen and oxygen to up the efficiency.]
posted by auto-correct at 3:17 PM on March 3, 2011 [2 favorites]
Everyone's entirely right that electrolysing and then burning hydrogen and water would waste more energy than you'd get out of it; it would have negative efficiency. But these guys aren't trying to "power a car with water", as you say in your question.
From the website: Aquygen® gas produced on-board a vehicle and introduced to the engine's combustion environment has demonstrated increased fuel economy as well as decreased vehicle emissions.
A regular internal combustion engine is not perfectly efficient. It cannot be perfectly efficient (see the Carnot Cycle). So what these guys are doing is trying to use hydrogen and oxygen gas to up the efficiency of your standard combustion engine by injecting the H2 and O2 into the gas tank. The idea being that the energy lost in electrolysis is made up for and then some in increased fuel efficiency. Kind of like how cars waste energy by braking, but hybrids take that wasted energy and put it back into the power train.
Who knows if this actually works. It won't be hard for people to test independently once the public gets their hands on the system. But it's not beyond the realm on the plausible. As far as I can see they aren't pretending to break the laws of thermodynamics, only to bring us a little bit closer to the efficiency limit.
[Please note that I'm not a chemical engineer, and have no idea what chemical process they think is happening between the gas, hydrogen and oxygen to up the efficiency.]
posted by auto-correct at 3:17 PM on March 3, 2011 [2 favorites]
I met a guy that showed me a setup that sounds very similar to this in his car. He was convinced that it gave him an increase in gas mileage.
posted by notned at 3:23 PM on March 3, 2011
posted by notned at 3:23 PM on March 3, 2011
Please note that I'm not a chemical engineer, and have no idea what chemical process they think is happening between the gas, hydrogen and oxygen to up the efficiency.
Gasoline blends are typically oxygenated to improve their efficiency, so this in and of itself wouldn't be surprising.
The only way that this system could actually increase fuel efficiency would be if it somehow took advantage of what would otherwise be waste energy, as how hybrids generate energy during braking. It's not clear exactly how they're powering electrolysis here, but I'm pretty sure it wouldn't work (i.e. lead to increased fuel efficiency) if it's driven straight off the alternator.
posted by mr_roboto at 3:25 PM on March 3, 2011
Gasoline blends are typically oxygenated to improve their efficiency, so this in and of itself wouldn't be surprising.
The only way that this system could actually increase fuel efficiency would be if it somehow took advantage of what would otherwise be waste energy, as how hybrids generate energy during braking. It's not clear exactly how they're powering electrolysis here, but I'm pretty sure it wouldn't work (i.e. lead to increased fuel efficiency) if it's driven straight off the alternator.
posted by mr_roboto at 3:25 PM on March 3, 2011
Adding hydrogen gas (H2) to the fuel-air mixture has the potential to improve efficiency and reduce emissions. Since hydrogen and its radicals diffuse very quickly, they are extremely reactive. This means flame speeds can increase and various mechanisms of pollutant generation can be mitigated. Hydrogen can embrittle steels however, and if the car is not programmed to take advantage of the addition of the effects (say by advancing spark, or changing valve timing), it's possible that performance might not increase and could even degrade (if the hydrogen enrichment is not suitably measured by the oxygen sensor).
There was considerable work done at MIT using plasma reforming of gasoline to obtain the hydrogen instead of electrolysis of water.
In some cases the idea is not that the energy to obtain hydrogen is less than what's gained from combustion, but that by satisfying the emissions constraints with hydrogen addition, you can free yourself to operate in a vastly more efficient operating regime.
The emissions-vs-efficiency picture is complicated. And fun.
posted by KevCed at 3:32 PM on March 3, 2011
There was considerable work done at MIT using plasma reforming of gasoline to obtain the hydrogen instead of electrolysis of water.
In some cases the idea is not that the energy to obtain hydrogen is less than what's gained from combustion, but that by satisfying the emissions constraints with hydrogen addition, you can free yourself to operate in a vastly more efficient operating regime.
The emissions-vs-efficiency picture is complicated. And fun.
posted by KevCed at 3:32 PM on March 3, 2011
Oops, I hit post instead of preview.
I wanted to add that gasoline engines are often operated in an non-ideal (off-peak) efficiency configuration due to emissions or engine-protection considerations like knock avoidance. If hydrogen improves your emissions or improves your knock margin you can improve engine efficiency in a conventional way.
Hydrogen is explosive and so far it has not prevailed in the overall cost-benefit-analysis of the factors that I mentioned.
posted by KevCed at 3:35 PM on March 3, 2011
I wanted to add that gasoline engines are often operated in an non-ideal (off-peak) efficiency configuration due to emissions or engine-protection considerations like knock avoidance. If hydrogen improves your emissions or improves your knock margin you can improve engine efficiency in a conventional way.
Hydrogen is explosive and so far it has not prevailed in the overall cost-benefit-analysis of the factors that I mentioned.
posted by KevCed at 3:35 PM on March 3, 2011
I know someone (third-hand) who does this. He apparently drives around with mason jars full of water and tubes and shit in his engine bay.
Does it work? Maybe a little.
Is it worth anything more than bragging rights and a certain street cred among the other eccentrics? No.
posted by ErikaB at 3:35 PM on March 3, 2011
Does it work? Maybe a little.
Is it worth anything more than bragging rights and a certain street cred among the other eccentrics? No.
posted by ErikaB at 3:35 PM on March 3, 2011
There was a mythbusters episode that looked at a similar device. From a recap site:
Hydrogen fuel cell generator
Hydrogen fuel cell generator: the car started, but it turned out it was due to leftover fuel. They tried again with the residual fuel gone and the car wouldn't even start.
Adam: "My God! It doesn't work! I can't believe it doesn't work. I found it on the Internet, man!"
Jamie rolled a tank of hydrogen gas over and squirted the gas directly into the carburetor. The car started up with the gas, much to the excitement of Jamie and Adam. It was so much fun they tried it again, only to get caught off guard as the gas exploded inside of the carb, ending that particular test.
posted by lilnublet at 3:57 PM on March 3, 2011
Hydrogen fuel cell generator
Hydrogen fuel cell generator: the car started, but it turned out it was due to leftover fuel. They tried again with the residual fuel gone and the car wouldn't even start.
Adam: "My God! It doesn't work! I can't believe it doesn't work. I found it on the Internet, man!"
Jamie rolled a tank of hydrogen gas over and squirted the gas directly into the carburetor. The car started up with the gas, much to the excitement of Jamie and Adam. It was so much fun they tried it again, only to get caught off guard as the gas exploded inside of the carb, ending that particular test.
posted by lilnublet at 3:57 PM on March 3, 2011
Sounds like something akin to Stanley Meyer's water fuel cell. This is massive amongst free energy conspiracy theory advocates.
posted by scruss at 5:43 PM on March 3, 2011
posted by scruss at 5:43 PM on March 3, 2011
See also David Mamet's play The Water Engine for an interesting take on the notion.
posted by chinston at 6:40 PM on March 3, 2011
posted by chinston at 6:40 PM on March 3, 2011
Response by poster: After rewatching the video (Sorry, it's not online or I'd link it) it was the Local News reporter who claimed the car was running a couple hundred miles on just a cup of water. The founder of the company makes no such claims, though they edited him to make it sound like he supported the claim.
His initial invention was a replacement for acetylene torches that would be safer since they would create enough hydrogen/oxygen on demand from electrolysis. (Which doesn't seem like a half bad invention.)
(And yeah, I'm well aware that a modern patent is not an indicator of function, I linked them for more info for the curious.)
(And I'm doing a giant facepalm for this being so incredibly obvious.)
posted by Ookseer at 7:18 PM on March 3, 2011
His initial invention was a replacement for acetylene torches that would be safer since they would create enough hydrogen/oxygen on demand from electrolysis. (Which doesn't seem like a half bad invention.)
(And yeah, I'm well aware that a modern patent is not an indicator of function, I linked them for more info for the curious.)
(And I'm doing a giant facepalm for this being so incredibly obvious.)
posted by Ookseer at 7:18 PM on March 3, 2011
This was discussed on the Straight Dope Boards a couple of years ago. Or at least a similar huckster was. Turns out that he's really using some aluminum composite in which water was just part of the reaction to run the car. Once you use up all that aluminum you'll need to get more and the process to create this fuel required quite a bit of electricity. Its an aluminum powered car, not a water powered car.
Its a lot like the potato powered clock. Its not powered by the potato and its disingenuous to suggest so. The chemical reaction in this case wears down the zinc not the potato. Its a zinc powered clock.
posted by damn dirty ape at 9:59 PM on March 3, 2011
Its a lot like the potato powered clock. Its not powered by the potato and its disingenuous to suggest so. The chemical reaction in this case wears down the zinc not the potato. Its a zinc powered clock.
posted by damn dirty ape at 9:59 PM on March 3, 2011
This thread is closed to new comments.
It would require more energy to electrolyze the water than it would take to power the car, however.
This is a simple consequence of the first and second laws of thermodynamics.
posted by mr_roboto at 2:34 PM on March 3, 2011 [4 favorites]