The Truth About Water-Powered Cars: Mechanic's Diary
It's one thing for a car to run on air, but do the latest claims of hydrogen-turned-oxygen-turned-electricity propulsion hold wateror feed in to the hysteria of the gas crunch? In his biweekly online column, PM's senior automotive editor focuses his chemistry prowess on the case of miracle water fuel, then builds an HHO car himself.
A Japanese startup appears to be using a fuel cell (left) to convert hydrogen and oxygen into electricity for its buzz-worthy water-powered prototype (middle), though an HHO mod like the one in PM's garage (right) might be a more practical solution. (Photographs by Genepax Co. and Mike Allen)
By Mike Allen
Published on: July 3, 2008
From a startup snagging headlines to DIYers posting plans, water-powered cars have been all over the Web recentlynot to mention stuffing my email inbox.
Yes, you can run your car on water. All it takes is to build a water-burning hybrid is the installation of a simple, often home-made electrolysis cell under the hood of your vehicle. The key is to take electricity from the cars electrical system to electrolyze water into a gaseous mixture of hydrogen and oxygen, often referred to as Browns Gas or HHO or oxyhydrogen. Typically, the mixture is in a ratio of 2:1 hydrogen atoms to oxygen atoms. This is then immediately piped into the intake manifold to replace some of the expensive gasoline youve been paying through the nose for these last couple of months. These simple kits will increase your fuel economy and decrease your bills and dependence on foreign petroleum by anywhere from 15 to 300 percent.
Theres even a Japanese company, Genepax, showing off a prototype that runs on nothing but water. On June 13 Reuters published a report on the prototype, complete with a now much-blogged-about video even showing an innocuous gray box in the Genepax vehicle'strunk supplying all the power to drive the car. All you have to do is add an occasional bottle of Evian (or tea, or whatever aqueous fluid is handy), then drive all over without ever needing gasoline.
So what do I think about all of this? Why havent I tested and written about this stuff? Its certain to Change the World As We Know It ... right?
Rubbish.
The only real definitive claim Genepax makes on its Web site is that its process is going to save the world from global warming. (A request for comment was not returned at press time.) Their Water Energy System (WES) appears to be nothing more than a fuel cell converting the hydrogen and oxygen back into electricity, which is used to run to a motor that drives the wheels. Fuel cell technology is well-understood and pretty efficient at changing hydrogen and oxygen into electricity and water, which is where we came in, right? Except the hydrogen came from water in the first placesomething doesnt add up here.
Heres the deal, people: There aint no such thing as a free lunch.
There is energy in water. Chemically, its locked up in the atomic bonds between the hydrogen and oxygen atoms. When the hydrogen and oxygen combine, whether its in a fuel cell, internal combustion engine running on hydrogen, or a jury-rigged pickup truck with an electrolysis cell in the bed, theres energy left over in the form of heat or electrons. Thats converted to mechanical energy by the pistons and crankshaft or electrical motors to move the vehicle.
Problem: It takes exactly the same amount of energy to pry those hydrogen and oxygen atoms apart inside the electrolysis cell as you get back when they recombine inside the fuel cell. The laws of thermodynamics havent changed, in spite of any hype you read on some blog or news aggregator. Subtract the losses to heat in the engine and alternator and electrolysis cell, and youre losing energy, not gaining itperiod.
But enough about Genepax, which is sort of tangential to my main thesis here, and on to a more common topic in my mail que: HHO as a means of extending the fuel economy of conventional IC engines.
HHO enthusiastsfrom hypermilers to Average Joes desperate to save at the pumpsuggest that hydrogen changes the way gasoline burns in the combustion chamber, making it burn more efficiently or faster. Okay, there have been a couple of engineering papers that suggest a trace of hydrogen can change the combustion characteristics of ultra-lean-burning stratified-charge engines. Properly managed H2 enrichment seems to increase the burn rate of the hydrocarbons in the cylinder, extracting more energy. However, these studies only suggest increases in fuel economy by a few percentage points and dont apply unless the engine is running far too lean for decent emissions. Thats a long way from the outrageous claims of as much as 300-percent improvements in economy that I see on the Internet and in my mailbox.
Theres no reason to believe that even more modest increases claimed by some of the ads could be achieved by a conventional, computer-controlled automobile engine running under closed-loop drivingthat is, the computers ability to sample the oxygen output of the engines exhaust in real time and slew the fuel/air ratio for big mpg and small emissions. The combustion chamber events are far different in the type of ultra-lean-burn engines where hydrogen enrichment has been seen to help. Ultra-lean means theres a lot of extra oxygen around for the hydrogen to have something to react withfar more than the very modest amount were sucking in from the typical homebrew hydrogen generator made from a Mason jar. And remember, these studies deal with hydrogen enrichment under closely-controlled lab conditions, not spraying an uncontrolled amount of hydrogen-oxygen mixture into your air cleaner.
Im building a water-electrolyzer carright now. The electrolysis cell assembly is on my workbench and ready to install, so stay tuned for the test results soon. If it works, then you can believe the hype.
look around you and and then look back 10 years and see how far things have moved on.
