Do Hydrogen Generators Work?
There have been many threads and posts discussing these new fangled hydrogen generators here on Allpar. Some claim mileage increases, some claim no such increases, and many members post their thoughts based on their understanding of the process with no real experience to rely upon. I thought it might be of interest to shed some light on the subject from a scientific perspective that will either prove or disprove the propensity to improve fuel economy with an HHO generator.
Before anything can possibly make sense, one must understand what goes on inside the combustion chamber of a running engine. Without this basic understanding, the nay-sayer’s win every time with their Laws of Thermodynamics and Conservation of Energy. Most of us picture the spark plug firing and a massive explosion pushing down on the piston much like a Rambo movie where a bomb goes off and bodies and debris are flying everywhere. How it really happens, very few have a real clue.
The combustion process actually begins on the compression stroke. As the piston moves up the cylinder bore, pressure and temperature escalate. Under these conditions, in the presence of catalytic substrates (aluminum pistons and heads, iron cylinder bores, platinum spark plugs, etc.) the larger fuel molecules begin to fracture. This fracturing process attacks the largest molecules first. It’s easier to break a 16 foot 2 X 4 than a 2 foot 2 X 4, and it’s easier to fracture Dodecane (a 12 carbon HC molecule found in gasoline) than a hexane (a 6 carbon HC molecule).
As these larger molecules break apart, they have a tendency to try to regroup. If you take a small 2-carbon chunk of HC molecule and reconnect it with another 2-carbon chunk, you get butane (2 + 2 = 4). That’s good. But if you regroup a couple of 6-carbon chunks, you end up with something that approaches kerosene called dodecane. That’s not good. This process occurs in 426 Hemis, 5.7 liter Hemis, as well as 3.5 HP Tecumseh engine powered lawn mowers.
When the spark plug fires, the only thing that spark initially accomplishes is to fracture one or both of the electron bonds in the oxygen molecules. This is endothermic in that it absorbs energy. Once there is an oxygen radical, it will electrically and magnetically gravitate toward the hydrogen atoms of the HC molecule. This attraction process also requires energy. The spark provides about 2000 degrees F. to enable this process. As the hydrogens are exchanged from the HC molecule to the oxygen atoms, there is a massive release of thermal energy. This is an exothermic reaction in that it releases energy. The energy release is far in excess of the energy required to soften the oxygen molecule bonds, and far in excess of the energy required to rip the bond from the HC molecule and attach it to the oxygen radical.
The oxygen molecule transforms from a stable diatomic molecule, to an ionized molecule, or even to free floating atoms, and then to what is called the OH radical. This would be an oxygen atom with only one hydrogen atom bonded. From there the OH radical will pluck an additional hydrogen from the HC molecule to stabilize as a water molecule (H20). 65% of the thermal energy release from the combustion process occurs through the formation of water.
As the hydrogens are consumed, the oxygen atoms will begin bonding with the carbon atoms forming carbon monoxide (CO). This yields 30% of the thermal energy release. Finally, the CO molecules bond with additional oxygen atoms to form carbon dioxide (CO2). This accounts for the remaining 5% of the thermal energy.
The flame propagation process creates increasing pressure and temperature pockets in the back corners of the combustion chamber. As this process happens, more of the larger HC molecules will fracture. Also, as the combustion process plays out, liquid droplets will vaporize from the heat.
With the heat generated by the burning fuel, the nitrogen and other gasses in the chamber begin to expand. It is this expansion process that creates the pressure that pushes down on the piston. Holy smokes was that technical! Hopefully you were able to follow the bouncing ball well enough to get a pretty good mental picture of the combustion process.
Now let’s look at the creation of HHO gas with a “hydrogen” generator. Faraday established a few parameters for the splitting of hydrogen and oxygen from water back in 1823. Since then, people have been able to exceed Faraday’s expectations with more modern technology than was available in the early 1800’s. It has been established that when the gasses are initially split from the water, they are in a monatomic form; free floating atoms. Over time, these atoms combine to form diatomic molecules. The amount of time varies based on pressure and temperature. Nevertheless, it is not even close to what our minds would perceive as instantaneous.
To split water into hydrogen and oxygen gas, electricity must be passed through the water. Since pure water cannot conduct electricity, an electrolyte is added. Electrolytes can be either acidic or caustic. Something that has an extreme Ph balance is acceptable. Most systems use caustics such as baking soda or lye.
Any two metal objects submersed in the electrolyte with a voltage potential that exceeds about 2 volts will produce this HHO gas. This would be the most simplistic version. To add a bit of efficiency, plates can be used. Stainless steel is the metal of choice, as it is extremely resistance to rust and corrosion. Aluminum would be the absolute worst choice, as it will chemically react to caustics and turn into a white powder (aluminum oxide) in a matter of seconds; even without a voltage potential.
If we were to place 2 plates in an electrolyte solution, apply battery voltage (13.5 volts viz.), we would draw (for the purpose of illustration) 15 amps of current and get 15 liters of HHO gas per hour. If we install an additional plate in the middle, called a neutral plate, we would still draw about 15 amps of current at battery voltage, but get 29 liters of HHO gas per hour. We can add even more neutral plates, adding to the output, without increasing the load… up to a point.
I think the actual threshold is 1.75 volts per cell. Anything less and nothing happens. Any voltage over threshold is converted to heat in the water-based electrolyte. The heat will increase the efficiency of the system. Therefore, it is advantageous to apply more voltage than threshold to achieve an efficient output. Typically, a range of 2.0 to 2.2 volts per cell is considered ideal. If we have 13.5 volts at the battery, we would want between 5 and 6 cells; which would equate to 6-7 plates. The space between the plates is a cell. To get one cell requires 2 plates. To get 6 cells would require 7 plates.
One method is to have corrugated plastic drain tubing that could house round plates. Dropping the plates in the corrugations would hold the plates at a given distance between each other, but would also have gaps that would allow voltage to pass around the plates; thus shorting out the voltage between the cathode and anode (+ and – voltage source). The folks that are getting the best results (versus Faraday’s Law) are sealing the plates so that the voltage can only pass through the plates and not around the plates. This sealing method reduces the amount of input watts needed to produce a given amount of HHO gas.
With a working knowledge of how an engine works, and a working knowledge of how an HHO gas generator works, let’s tie it all together to see if these devices have any merit. We know that we are getting a certain percentage of hydrogen atoms and a certain percentage of diatomic hydrogen gas. We know we are getting a percentage of oxygen atoms and a certain percentage of diatomic oxygen gas.
Remember in the early part of the combustion process when larger HC molecules are fracturing? Adding hydrogen to the air intake provides a stabilizing function to the cracked molecules. Instead of HC molecule chunks bonding with each other, they would more readily bond with free hydrogen atoms. This would stabilize the fractured HCs as methane, ethane, propane, butane, pentane, etc. (1, 2, 3, 4, and 5 carbon HC molecules). This has significance in that gasoline engines are considered about 18% efficient, but propane engines are about 40% efficient, and natural gas (methane) engines run upwards of 60% efficient. By thermal catalytically cracking the larger gasoline molecules, then stabilizing them as more efficient gaseous molecules, the engine becomes more efficient.
In 1911 another genius named Avogadro figured out that a molecule takes up a given amount of space in the aether. A gallon of diesel fuel, a gallon of gasoline, and a gallon of propane all have approximately the same number of molecules. If we split a dodecane molecule into 2 hexane molecules, then stabilize both molecules with the addition of hydrogen, we get 2X the volume. Let me restate this: If we split larger HC molecules into smaller HC molecules and stabilize them with additional hydrogen, we get more fuel than we apparently started with! We are making more fuel in the combustion chamber as the hydrogen does its thing! Furthermore, the resultant fuel is more efficiently combusted!
The monatomic oxygens that are drawn into the engine from the HHO generator have a substantial role to play as well. In the combustion process, a significant amount of energy is required to break the bonds between the oxygen atoms to create radicals. The oxygen from the HHO generator is already (at least in part) in a radical form. This means that these oxygens can start reeking havoc on the HC molecules with less thermal energy absorption. This allows for a more rapid burn.
Why is a more rapid burn beneficial? Because there is only a small window of time for the engine to extract whatever energy from the fuel that it can. Beyond this window, the fuel may burn, but it contributes nothing to the turning of the wheels. This out-of-window energy release is converted to heat in the cooling system and exhaust system.
The spark plug fires before the piston reaches TDC on the compression stroke. As fuel begins to burn, there is a rising temperature and pressure that begins to push harder on the piston. This is a parasitic drag that absorbs energy that could otherwise be used to power the vehicle. Why do we try to add ignition advance if this is the case? Because of what engineers call “Critical Crank Angle”. The piston remains motionless from about 14 degrees BTDC to about 14 degrees ATDC. This is the best place to build pressure. As the piston begins to move, it converts the potential energy into kinetic energy. Still, it takes a certain amount of time to get the flame propagation process going. That requires spark timing to initiate the combustion process before the piston gets to the top. If we were able to speed up the burn, we could reach peak cylinder pressure by critical crank angle with less spark advance. This would reduce parasitic losses.
To better understand this window of opportunity, consider that as the piston descends the bore, it accelerates. As it accelerates, it will eventually outrun the pressure wave. If you watch a bow and arrow, the arrow will begin to walk away from the string before the string reaches the center (straight) position. We only tap the pressure created near TDC and convert it into power. The rest is dissipated as heat.
Before proceeding, let’s consider an analogy. If you were to take an 80# arched bow and an 80# compound bow, give each 3 arrows, then shoot both for distance, the compound bow would consistently outshoot the arched bow. In fact, not by a little, but by a considerable amount. How can that be when both bows are rated at the same 80#? The arched bow delivers its contained energy (80#) over a string travel of about 5-6 inches, while the compound bow delivers that same amount of energy (80#) over a mere distance of perhaps 2 inches. That concentration of energy delivery yields much more work done.
By producing a much faster burn in the combustion process, we are concentrating whatever energy the fuel contains into a much tighter window of delivery. We are turning our arched bow engine into a compound bow engine.
The bottom line is that chemically and physically, HHO gas speeds up the burn, creates a much more efficient burn, delivers more power from the same amount of fuel, and yields better economy. There is, however, a catch (you just knew there had to be one).
Our modern engines are controlled by a sophisticated computer that is programmed to deliver a certain amount of fuel under various conditions, and ignite it at a given time. The additional fuel created by the hydrogen atoms means we can get a much more efficient burn with less liquid fuel. We aren’t necessarily leaning the engine out as much as removing the now not needed excess fuel.
If you take an exhaust gas reading before installing an HHO generator, you will probably see mostly zeros. Our modern automobiles are extremely clean burning out the exhaust. After you install the HHO generator, you will see a rise in HC and CO pollutants. If you lean out the fuel; or put another way, target a higher oxygen content in the exhaust system via the oxygen sensor feed back system, you will see the HC and CO readings drop back down. This will be verification that you are not actually creating a lean condition, but merely restoring a proper air-fuel ratio.
If you add a larger throttle body, hotter cam, oversized injectors, cold air intake, free flowing header and exhaust, the vehicle probably would run like garbage. To maximize the hardware changes, you have to modify the software. The same can be said for economizers. By changing the combustion efficiency without compensating for it with software changes, the gains aren’t maximized. There is a wealth of information on www.mpgResearch.com about tuning modern vehicles for mileage.
Overall, HHO generators have the potential to double fuel economy on many vehicles. The critical part is tuning for it.
| Mike Holler, known on Allpar forums as mpgmike, also contributes to mpgResearch.com. He has contributed many columns to Allpar: | |
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