While specifics vary, this is the basic design concept of the hydrogen generators offered for sale.
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My commute home in the evening can take up to two hours, depending on traffic. To avoid frustration, I have a favorite afternoon
radio show that always keeps me smiling. On the way home the other day, the DJs were encouraging listeners to come up with
something spectacular in order to earn tickets to a very hot concert that was coming to town. A young lady called in and this
is what she offered.
"My husband says he'll install hydrogen generators on all your cars for free in return for the tickets."
The female DJ on the show responded, "Is that the thing that jacks up your car? That would be cool!" Amidst the laughter from
the other two male DJs, the caller said, "No...it is a device that turns water into gas for your car, and will add six to
seven miles per gallon." The DJs respectfully declined, saying that they could not benefit directly from giving away the tickets.
And that was it. No mention of whether there was any truth to the claim. I wondered how many listeners were intrigued by what
the young lady had said, and how many shops were called the following day and asked about this miracle device? So I thought
I'd do a little digging and share what I found.Hydrogen as a Fuel
A Ford F-250 concept can run on regular fuel, E85 or hydrogen. The supercharger only operates when the engine runs on hydrogen.
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Hydrogen is the most abundant element in the universe. It has the second widest range of flammability of any gas, able to
combust in air in concentrations as little as 4 percent and as great as 75 percent. Compare that to gasoline, which is only
combustible in air in a much narrower range — from 1.4 percent to 7.6 percent. Hydrogen also is easily ignited, even by a
small static electricity spark. It is a low-density gas, lighter than air, and contains three times the energy of gasoline
by mass.
These factors make hydrogen attractive as a fuel substitute or supplement. Alone, it can be run at extremely lean ratios.
As a supplement, it promotes better ignitability, a higher flame speed and reduces knock, which, in turn, allows for a leaner
gas mixture to be used with higher compression ratios.
LEARNING ON THE WEB
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The drawback is that there is no such thing as "free" hydrogen. All naturally occurring hydrogen molecules are attached to
another element. Gas and diesel fuel, for example, contain two hydrogen molecules for every carbon molecule. Water, of course,
is two parts hydrogen and one part oxygen. In order to get the hydrogen, we have to separate these chemical bonds. Two methods
are used to do so: reformation and electrolysis.
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There are three ways hydrogen currently is being used as an automotive fuel source. Hydrogen fuel cells are arguably the most
known because they produce zero emissions, with their only exhaust byproduct being water. These fuel cells combine hydrogen
and oxygen in an electrochemical process, resulting in the production of electricity. This electricity is then used to power
an electric motor, which in turn drives the car down the road. There are several technologies, with the Proton Exchange Membrane
(PEM) being one of the more common. An individual PEM cell produces about 1.2 volts, but is most efficient when voltage levels
are closer to 0.5 to 0.6 volts. The cells are wired in series to form stacks that can provide the total electrical power needed
to power the car.
Hydrogen and oxygen combine in a chemical reaction to produce electricity in this PEM cell.
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Another method is to use hydrogen as a replacement for gas or diesel in a conventional internal combustion engine. Ford has
built such prototypes, as have a few other manufacturers. But because of the low density of hydrogen, more volume is needed
to produce the same power from a given displacement versus gasoline. Supercharging is one solution to packing in that volume.
Other factors also have to be considered and designed for. The low ignition requirements of hydrogen require precautions against
pre-ignition, and combustion chamber designs differ from those using gasoline as the primary fuel. The hydrogen fuel source
is stored on board, in either a liquid form or as a high-pressure gas.
Hydrogen also can be used to supplement gas or diesel fuel. On these systems, hydrogen is not stored, but produced on the
vehicle using electrolysis to separate water molecules into their base elements: hydrogen and oxygen. In use on many commercial
diesels, fuel economy has been improved up to 10 percent and tailpipe emissions have been reduced. These systems produce only
very small quantities of hydrogen, usually on demand as the engine requirements warrant. It is this concept that is often
advertised as "running your car on water," with the promise of fuel economy increases of 50 percent or more.
Posted 2009-06-20 01:22:45.0
