How Hydrogen Helps: The Scientific Principles of Spark-Engine Performance When Supplemented with Hydrogen

Electrolytic Injection is basically a fuel-savings concept that is really taking off right now. I have seen a lot of government and university research into the basic principles, which I will get into, but a lot of the raw research sidesteps the main issue of fuel efficiency. Why anyone really cares about emissions reductions is beyond my needs for my personal vehicles. The only people who really seem to care about carbon dioxide emissions are those who misconstrue the whole global warming issue.

What we get from the electrolysis of water is a more efficient engine that burns hydrogen along with the normal fuel. The reason for this has less to do with the amount of hydrogen than most people think. What I would call a bit of a misunderstanding in the people toying with HHO in their garages and sheds is that the amount of HHO produced by electrolysis is an extremely small amount compared to what it would take to run your car on water. Do you realize that it would take thousands of times more HHO production to run your car completely on HHO? Many people do not see this.

It is obvious that these hydrogen cells produce a very small amount of hydrogen and oxygen. Why? Because the mass of water used by them per hour is exceedingly small. But yet they still improve the mpg (miles per gallon) of your car or truck. That is all due to a fundamental chemical difference in the way an internal combustion engine responds when fed with hydrogen as a supplement to its normal fuel. The high flame speed of hydrogen, coupled with hydrogen’s small molecular mass, has profound repercussions on the way an engine runs. And this is true for exceedingly small amounts of hydrogen in the airstream.

What a lot of researchers have discovered, as early as 1977 when NASA’s Lewis Research Center wrote a paper on it, is that using hydrogen as a supplemental fuel allows a gasoline engine to run leaner than its stoichiometric ratio of about 14.7 to 1 (air to gasoline) by mass. By adding hydrogen, NASA in 1977 discovered you can run a high compression gas engine at an equivalence ratio of about 0.75 (a Lambda of 1.33) and obtain a higher engine thermal efficiency over the standard gasoline engine. This equates to about a 20 to 1 air to gasoline ratio by mass, which is very lean. *See Figure 11.

Why does leaning out the fuel matter? Because lean means less fuel. And since hydrogen has a higher flame speed and higher peak temperature, the result is a more efficient car. In the NASA test, they kept engine rpm and power output constant while adjusting the air and gasoline proportions. They, in effect, reduced the amount of gasoline burned while increasing the amount of air being sucked into the engine. If this sounds a little like how a diesel engine obtains its efficiency, then you are correct. Diesel engines are almost always run “lean,” and this is one reason why a diesel engine will outperform a gasoline engine.

So we have documented evidence, more than 30 years old, that hydrogen as a supplemental fuel does the following for a spark-ignited gasoline engine:

• Increases the lean flammability limit for gasoline engines to around 0.55. equivalence ratio (Lambda=1.8), or 27 to 1 air to gasoline ratio.
• Greatly increases the flame speed of the combustion. *See Figure 9.
• Increases the thermal efficiency of the engine. *See Figure 11.
• Decreases the level of carbon monoxide in the exhaust. *See Figure 14.
• Requires a major retarding of the timing to reduce the crank angle at which the spark ignites the fuel. *See Figure 8.
• Lowers the levels of oxides-of-nitrogen (NO_x) in the exhaust, especially for ultra-lean equivalence ratios that hydrogen makes possible. *See Figure 12. “Comparing NO_x levels at the 0.94 equivalence ratio and the minimum-energy-consumption equivalence ratio of 0.66 for hydrogen-gasoline shows [a large] reduction, by a factor of 5.” (Ref: NASA, p.16)

And then the final conclusion, not specifically covered by NASA, is that gasoline fuel consumption would obviously go down considerably by running the engine leaner and using hydrogen as a supplemental fuel. Why didn’t they make this assertion? I am under the impression that NASA may have been doing the research trying to come up with a vehicle that could operate in rarified atmospheres, presumably atmospheres with very little oxygen, in which lean combustion would be extremely useful. And since hydrogen was a fuel they had researched for other purposes, the 1977 research probably had some sort of thrust towards advanced engine design. This was their primary conclusion:

“Adding small amounts of hydrogen to gasoline produced efficient lean operation by increasing the apparent flame speed and reducing ignition lag.”

Notice that they say small amounts. In their case, they used about 7% by mass hydrogen in combination with the gasoline. This was about 635 g/hr for a 472 cu. in. (7.73 L) engine at 2140 rpm. Not many people might understand that this is the equivalent of nearly 2 liters per second of hydrogen gas in an engine consuming:

7.73 L/intake * 2140 Rev/min * 1 intake/2 Rev * 1 min/60 sec = 138 L/sec

The ratio is therefore:

1.98 L/sec H2 to 138 L/sec total intake, which makes it 1.43% H2 by volume. But because of hydrogen’s light molecule, the mass ratio is 940 parts air to one part hydrogen, or 0.106% hydrogen by mass.

It sounds like NASA is pulling our leg. They fill the airstream with just 0.1% hydrogen (by mass) and get that kind of result? So let’s check to see if this is reasonable data. Remember, they also said hydrogen made up 7% of the mass of fuel consumed. They list 4 values for specific gravity, so we will choose 780 g/L as the density of gasoline (listed at 294 K). They also claimed that 2140 rpm is what a 1969 Cadillac engine would rev at 55 mph cruise. So we check the math and make no assumptions. The calculated fuel consumption rate is 2.86 gal. of gasoline per hour if we have a perfect 7% mass fraction. At 55 mph, that gives us a fuel mileage estimate of a whopping 19.25 miles per gallon in a 1969 Cadillac. Wow, and all they had to do was add about 1.98 g H2 per second.

Realistic? Yes. The calculations all seem to correlate to what we believe a Cadillac could do. My best guess is that 10 or perhaps 11 mpg would be a typical figure for that engine, although I have seen some ranges beyond that. I believe that Motor Trend’s April 1969 testing concluded a 9.2 to 11.8 mpg range for this car. So we are roughly seeing an improvement of 90% over stock engine performance.

Now, is it possible to extrapolate? Not really. But since not very much research exists like NASA’s detailed report of 1977, we can perhaps tweak the numbers to see if an HHO kit will have a similar effect. Just so you know, there is no conceivable way to introduce 2 grams of hydrogen per second using existing electrolysis technology. Because for every 2 grams of hydrogen, we’re talking about 16 g of oxygen. Coincidentally, this is a mole of liquid water per second. And it would be 1.5 moles of HHO vapor per second, which at standard temperature and pressure, we know is 22.4 * 1.5 = 33.6 liters of HHO per second or 121,000 liters per hour HHO. A typical electrolytic cell produces around 120 liters of HHO per hour, or 1,000 times less. We are in big trouble in HHO land! We produce 1.98 mg of Hydrogen by electrolytic injection, where NASA was using 1.98 g of Hydrogen each second. (**See Absurd note)

But there are a few principles we cannot forget. First off, our HHO kits produce some pure oxygen, which permit a leaner combustion. This helps. But most significantly, most HHO kits are designed to lean out the fuel in some fashion. Every engine maker knows that leaning out the fuel is better for fuel economy and lowers combustion temperatures (*See Table III and Note), but the concern is California emissions. Everyone is afraid to cause any higher emissions than the CARB (California Air Resources Board) recommends, and so essentially all of the cars on the road today have been forced to operate at stoichiometric air to fuel ratios and waste a few precious percent of fuel economy. We have a case in which we can experientially know that conventional wisdom (operating at the stoichiometric air-to-fuel ratio to limit emissions) is misguided by convenience. Stoichiometric operation has had its heyday, and many experimenters are demonstrating that lean is clean and efficient.

So can we overcome both obstacles? Yes. Indeed, running leaner can sometimes be beneficial due to the lower average temperatures, although the higher peak cylinder temperature is bad for NO_x. And in most cases, the leaner fuel will prevent a lot of the CO from the exhaust. So what we are seeing from the field is that emissions with an HHO kit are typically lower for some things, but not all things. Just like any real-world situation, the results will vary widely depending on the car’s engine and the amount of leaning you have done. It also varies with the amount of crank angle reduction, which will depend on a lot of sensors that our kits never touch. (The NASA researchers had the advantage of making quick adjustments to engine timing using the distributor. Most modern cars adjust timing electronically.)

Although the amounts of hydrogen we are generating with HHO kits would seem insignificant, they are in fact enough to have a positive effect on fuel economy. We have demonstrative proof that gas mileage improves with HHO. We may not see a 90% improvement (like NASA did with their 1969 Cadillac 472 engine) simply because we cannot pump an engine with 2 g/second Hydrogen with current technology.

I will leave off some of the mileage improvement specifics for another time. I have taken a few days just to write this during a busy time in the business. So I hope you enjoy finally seeing some scientific basis for running your car on water. My conclusion is: without doubt, the technology works. The main question, to be put to the scientific analysis is: how well does it work in some real-world applications?

I have invested a lot of money into a few novel ways for testing fuel consumption. It will probably take me until early 2009 to complete the test, so don’t expect anything overnight.

Reference: Cassidy, John F., Lewis Research Center, NASA Technical Note, TN D-8487, “Emissions and Total Energy Consumption of a Multicylinder Piston Engine Running on Gasoline and a Hydrogen-Gasoline Mixture," May 1977.

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Figure 9

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Figure 11

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Figure 14

Table III

*Note on combustion temperatures: Many people erroneously believe that exhaust gas temperature (EGT) rises when an engine is run lean and the timing is adjusted for fuel efficiency. EGT will decrease with lean operation, but it will increase as a gasoline engine approaches ultralean operation. Notice that with hydrogen addition, EGT only decreases, even at ultralean conditions. Table III is presented here to demonstrate that exhaust temperatures indeed go down with lean operation.

The understandable reason for the decrease in EGT is that during lean operation, thermal efficiency (*see Figure 11) and fuel economy is improved. When no hydrogen is added and ultra-lean operation is attempted, thermal efficiency plummets and consequently EGT rises.

**Absurd Note: At the rate of approximately 2 g/sec hydrogen, we would need to produce 18 g/sec HHO. For every 2 g H₂, we produce 16 g O₂ from H₂O. Therefore, in a minute, we would be consuming 1.080 kg H₂O, or about a liter per minute of water, which would exceed most HHO kit designs. For a typical 2 hour trip, we would need 35 gallons of water on board to produce the 14 kg of hydrogen consumed by the engine. This compares to only 5.7 gallons of gas used in the same two hours at 55 mph and 19.25 mpg.

The next assumption is merely a rule of thumb. There are HHO generators today which require about 7 amps at 12 VDC per lpm HHO generated. To further the absurdity, let's produce 18 g/sec HHO, or 2,016 lpm or 121,000 lph HHO and see what the current requirements might be. A simple calculation shows that we need to produce 14.112 kA of current. We might further note that we would need around 169 kW of electrical power to generate that much current. This compares with the 1969 Cadillac engine that was only generating a cool 36 hp/27 kW brake horsepower. Obviously, I hope no one in their right mind ever thought that a car could run entirely on water using conventional electrolysis as a source of the hydrogen. Furthermore, this level of HHO would still need gasoline as its primary power source.