HHO Generator
For HFE (hydrogen fuel enhancement),
also known as HFI (hydrogen fuel injection), HOH, Hydroxy, and Brown's Gas

This sounds like a lot of work, but I feel the rewards are worth it.

Scenario 1  The days are cold, or at least cool. You get in your car and start the engine for a trip to work or the store. The hydrogen generator cells are too cool to produce enough H2 to really make a difference. If you have retarded the timing as many recommend to prevent ping (pre-ignition. In fact some recommend retardation after TDC), you are likely to get worse fuel mileage than if  you had never installed the hydrogen booster.

Scenario 2  The day is hot and you have the H2 generator installed under the hood. Temperatures there can reach 220°F or even higher. This can cause the generator to go into thermal run away, which evaporates the electrolyte sending caustic fumes into your expensive engine, or at the very least erode the plates in the generator.

Scenario 3  A nice day. You have just installed your hydrogen boost system and are adjusting the carburetor with the engine warmed up (recommended). You can lean out the idle mix, and back off on the idle stop screw. But the next morning the car refuses to idle properly until the engine (and likely the H2 generator) are up to operating temperatures.

Scenario 4  It is a cold day and you have a few stops around town to make before a long highway trip. The car is running nicely now that the H2 gen and the engine are up to operating temperatures.
You get on the freeway, and cold air coming in through the radiator cools your under-the-hood hydrogen generator installation. As a result, you get poor gas mileage for your trip.

Scenario 5  It is summer, and you have the install in the car. With the windows rolled up it can get quite hot. Once I measured 200° on the dashboard. Another summer I literally blistered my hand shifting from park to drive. This is why we need a fan to prevent thermal runaway in the generator.

A few ideas to help remedy those scenarios...

Things to consider when choosing where to install
The trunk had already been ruled out for two reasons:
a.  It is an enclosed space and therefore dangerous in case H2 accumulates.
b.  Oxygen is produced along with the hydrogen. Very bad to have in the trunk since that is where the gas filler hose is!

Under the hood seems obvious, but space is quite limited, and the under hood temperature could vary from below zero °F to around 220 °F or even higher. Low temperatures greatly reduce cell efficiency. High temperatures can destroy the cells and possibly damage the engine.

Inside the car temperatures are far more moderate, especially with climate control, so the transmission hump is the planned permanent home. I made sort of a console looking thing that has indicator lights and maybe later will have an ammeter.

Another place to consider is just in front of the seat under the driver's thighs. Of course, a long thin box would be better (6 cells in a line). In a pickup truck, perhaps behind the seat would be good.

Consider smaller cells  

A massive 2 or 3 quart generator cell will take much longer to warm up than a number of smaller cells. Glass was chosen for a number of reasons. I can see the liquid level and color of the solution. The cells will cool easier than PVC pipe. Since they are canning jars, the seals have proved effective even at extreme temperatures. On the down side, the jars must never be allowed to freeze. But then other types of cell containers should not be allowed to freeze either.

The jars I am using are 8oz, for a total of 48 ounces. They are not filled to the top, so lets say they contain about 38 ounces. This should easily be about 18 hours of driving before needed a refill.

Preheat the cells  Applying power to the cells for a period before starting the car is out of the question, since explosive gasses will accumulate. Perhaps some sort of heating element powered by line voltage could be used. This would be annoying to have to do unless you lived in a very cold area where your car was plugged in anyway to keep the cooling system warm. For my area, two small 4 or 7 watt light bulbs might do. I would not recommend using the main battery to power some sort of warming device overnight. However, I have working a temperature controlled heater that I think might be useful to preheat for as much as an hour before driving.
See temperature control page here

A cooling fan switch  On the previous page you saw an old computer fan installed on the generator box. A manual switch to turn the fan off on cold days might be advisable, but a temperature controlled switch that sensed the temperature of the jars would be even better.

Electrode shape  Some believe that the electrodes should be near the bottom of the cell so they will always have electrolyte covering them. My approach was slightly different. As the water is used, the electrolyte concentration becomes stronger. I hope that by using long electrodes that only half the area will be exposed when half the water is used but the electrolyte will be twice as strong. That should keep gas production more uniform.

March 19, 08  Here is an approximate price list for the 12 cells.
$8          Mason jars for 12
$1.29     3/16 brass tubing for connections  
$7.74     6 strips of stainless 12" x 3/4
$0.00     48 insulating washers made from packing material. (Was $12 for nylon washers.)
$10.00   Stainless 24@ 10x24 screws, 72 nuts, 48 SS washers

$3.00     tube of Goop adhesive sealant
total $21.03
On hand was... titanium sheet, solder, wire and eyelets, vacuum hose, plastic fittings (as used in lawn irrigations systems).

March 21, 08

Box is ready, all the cells have been tested and checked for leaks.

March 24, 08

LOTS of hydrogen.

March 30, 08

Covering the top with Naugahyde. Far from necessary, but I wanted the box to blend into the interior at least some.

April 5, 08
I had installed a used transistor that turned out to be bad. After a quick trip to Radio Shack, the control board was installed and tested. Works great! The heater is set to shut off at 72 degrees. The fans cycle on and off when the set point is reached as they should. The fans will be set to come on at about 95 degrees. Plenty of hydrogen is being made at 77 and the bubbler sounds like briskly boiling water and is increasing as the temperature rises.

The current is 13.5 amps at 88°F. Should be close to the planned 15 amps at 95°.

The big disappointment was the ammeter I bought on eBay. It lasted one day before it died. Will use a cheap pocket DMM while I am fighting with the Chinese company for a replacement.

First road test with 12 cell generator
The light came on indicating it was heating the cells and went off after about 5 minutes. In town the light indicating the cooling fans were on cycled on and off. On the highway the fans stayed on, which is the way I intended it to work. The timing had to be retarded a little more.

At 35 the vacuum was 13-13.5 inches
At 45, 14 inches
At 55 miles an hour a solid 15 inches.
Ambient temperature 76°F

Before, with the 6 cell generator the vacuum was higher at lower speeds. This may mean more tweaking of the timing is in order.

Murphy's Law again. The low vacuum was cause by a massive leak in the EGR valve. In spite of that, I got the best gas mileage I have had so far. But it means I need to start the tweaking and testing process over again one the leak is permanently fixed.

April 11,08
The leak is fixed, the winds have died down (had 60mph gusts) and the tank filled again. The idle mixture screws are adjusted to less than 1/4 turn, the leanest it has ever been. BTW, this is a new carburetor, not a rebuilt.

April 12, 08
I put 25 miles on the car. The spark plugs were black and sooty after the vacuum leak and I was going to replace them. Now they are white and spotless like new.  I have slightly smaller jets on order... #62 to replace the #65 that were in the new carb. Original carb had #64. At this altitude Holley says I can safely go two sizes smaller.

The temperature control circuit is working perfectly. I can tidy up the wiring while waiting for the new jets to arrive.

Several people around town have asked if I sell HHO generators.

April 16, 08
The new main jets arrived. I am impressed. Only $1.50 for Priority Mail, $4.75 for the pair of jets. I calculate 9.5% drop in gasoline by adjusting it for altitude. These are the folks: Allstate Carburetor
They have parts for Holley, Webber, and GM carbs.

Now designing a water injection system.


May 5, 08
The water injection is working great. So far, the HHO has not shown me what others claim in the way of fuel efficiency.  No further testing will be done on HHO, but will continue on water injection.

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Things that may have to be addressed to make a practical system.

• The are great differences in production rates with variation in temperatures. I can't expect the generator to make much difference in my fuel economy until it warms up on a cold day, which may make it useless for short trips in winter. I believe I have solved that.

• In summer, an under the hood installation may experience "runaway". When the electrolyte gets hot enough, the current goes up, making it hotter, which makes the current go up.... etc.

• Output (and cell temp) varies as water is used to make hydrogen. Some sort of automatic level would be quite helpful.

• From what I have read, cars with electronic fuel injection and computerized fuel/air ratio make getting hydrogen boost working difficult.

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Summary of what I have found out

• What has worked for others may not work for you. It seems each cell design has its own characteristics, and you will need to experiment.

• Efficiency seems best if the voltage is kept low, but not in every case. I have used 12 volts in bench tests with success. Many say the best voltage is between 1.5-2 volts, but yours may NOT work at 2 volts or below. This may vary with the type of electrolyte used, electrolyte strength, electrolyte purity, plate material or alloy, plate shape, spacing, water purity, temperature, and other factors. 

• Large plate size may not be the best answer. My plates are small; 1/2" x 5". If the electrolyte becomes discolored, it usually means the plates are being eaten away. A greater number of smaller cells may give the best electrode life and better gas production.

• The efficiency increases with temperature. There MUST be heat generated. Energy is used in the process because ions in the water need to move to carry electricity, and this movement heats up the water. Note that H2 is generated at the negative plate, and O at the other. They came from the same molecule, so obviously the ions had to travel the distance between plates. So far, increasing the electrolyte strength (and heat), produces sludge and eats the plates before efficiency drops.  While speaking of temperature, I tried warming just one cell. The current remains unchanged. This is a bit baffling. It is as if the resistance of one cell governs the overall performance. This should be kept in mind for those of you who want to try 5 or 6 cells in series.

• Amount of gas produced is NOT proportional to the current. Gen cells can have great differences in efficiency.   Engines will see a gain in fuel economy and reduced emissions with "as little as 10 amps" for an HHO generator. This does NOT mean the goal is a 10 amp generator; it means we want an efficient generator of about 10 amps. Don't do as some have, and just add electrolyte until it reaches 10 amps. It may be better to add more cells instead.

• Be very suspicious of claims of 1 liter per minute with 10 amps consumed per generator. Amperes is a measurement of force, not power. It takes 4 kilowatt hours of power to make 1 cubic meter (1,000 liters) of hydrogen assuming high efficiency (say, 80% or better). This means 10 amps at 12 volts (120 watts) can only make .5 liters of hydrogen per minute.

• While on the subject of power, one horsepower = 746 watts. 10 amps at 12 volts is 120 watts, or  .16 horsepower.

• Don't use windshield washer fluid, ethylene glycol, or methanol/ethanol intended as a gas tank additive for the hydrogen generator antifreeze agent. They all contain anti-corrosion inhibitors that are guaranteed to deteriorate your electrolyte, may eat your plates, create who-knows-what as gasses or compounds and pump those into the engine.

• The small blue aquarium bubblers have a binder that is attacked by weak acid. There are white ceramic ones that seem better suited. Lee's "Discard-A-Stone" is one brand I am investigating.

• At 5 volts regulated, no sludge or discoloration is visible when titanium used as the negative plate. This is a breakthrough. After 24 hours the pH is 10 (expected) but no erosion of either plate. I am convinced that the sludge means something has changed, be it the electrolyte breaking down, or the electrodes being eaten, or both.

• I now know why the gas production (and plate erosion) seems to be at the top of the plates. Warm water rises to the top of the cell so that is where it is most active.

• A minor side effect of H2 booster use is that when I take my foot off the gas pedal, the engine slows gradually rather than quickly going to the idle speed. I suspect that is because there is H2 and O2 still getting into the engine once the throttle plate is closed.

• Weller's Law (me) For any given cell design and electrolyte combination, there will be a temperature high enough that the cells will go into thermal runaway. At the other extreme, there will be some temperature too low for the cell to draw enough current to ever warm up.

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A few facts from various sources

• One liter of hydrogen weighs 0.09 g 
  
• One liter of water can produce 1234.44 liters of hydrogen and 604.69 liters of oxygen as gasses...  Total  1,839.13 liters.
• Flame front propagation for an H2/O2 mixture is taken to be 8300 feet per second.
• The self-ignition temperature of hydrogen is 520 degrees Celsius, or 968°F. Gasoline varies from 228-501 degrees Celsius.
• The lower flammable limit for H2 in air is 4.1% concentration.
• Flame front velocity varies greatly with H2/air concentration.

HHO page 1

HHO Temperature Control

HHO Cheap

Electrostatic air filter

Modified PCV Trap

Water Injection

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