I found the following text on a website selling a fuel hydrogenation device. I won’t like to the site, because the device they’re promoting is almost certainly a scam:

“Increase your gas mileage 20-90% by adding a supplemental hydrogen generator to your car! A supplemental hydrogen generator works simply enough – you put distilled water in a special canister in your car, and electricity from your car’s battery is used to separate that water into hydrogen and oxygen. The hydrogen is added to your car’s fuel because hydrogen burns very well (hydrogen is a very combustible gas), and it reduces the amount of gas you use! The oxygen is added to the air your car breathes in. Oxygen is needed for combustion, and more of it makes your car more efficient. One gallon of water is enough to provide oxygen and hydrogen for hundreds of miles!”

While there is some science to support adding hydrogen to fuel to improve combustion, the people selling these devices are usually full of…beans. Here’s more information about hydrogenated fuels, how they can work, and some advice about spotting a scam.

Adding Hydrogen To Fuel Can Boost Fuel Economy

When fuel and air are mixed together in the cylinder of your engine, you get combustion. Combustion – which is a fancy word for “controlled explosion” – generates force to move a piston, as well as heat. Of course, different types of fuel combust differently, and this means that altering the chemical composition of fuel can have a pretty big impact on the combustion process.

If we’re talking about a diesel combustion process that uses diesel fuel, than there’s quite a bit of evidence that adding hydrogen to this fuel can improve diesel fuel economy:

DynaCERT, which makes fuel hydrogenation devices for commercial diesel trucks, has provided documentation that their devices save fuel

Popular Mechanics has reported similar claims from another device company HyTech Power

Both DynaCERT and Popular Mechanics explain that, because hydrogen combusts more quickly than diesel, adding hydrogen to diesel fuel can improve engine efficiency. The fast-burning hydrogen additive ensures more complete combustion, to the point that fuel economy can improve as much as 20%.

While there’s a dearth of research to support these claims (I challenge anyone to find a paper about this technology on SAE.org), it’s hard to argue with performance guarantees or 3rd party testing lab results. There’s every reason in the world to take these companies at their word.

But for every company like DynaCERT or HyTech Power, there’s at least one charlatan hawking “HHO Kits” that promise to turn water into fuel, with fantastic promises about fuel economy improvements (like the 90% promised in the copy at the top of this article). It’s impossible to believe.

Why Adding Hydrogen To Gasoline Probably Won’t Help You

While there is research to suggest that adding hydrogen to gasoline can boost flame speed and enhance combustion (see this paper, this paper, or this paper from way back in 1936), it’s unlikely that anyone with a modern gas powered car would see much benefit from hydrogenated fuel. This is because modern gasoline engines are designed to keep combustion temperatures down, thus negating a lot of the hydrogenation benefit.

If you study the three papers linked to above, you’ll learn that hydrogen has the following impacts:

The amount of heat from the combustion process increases This additional heat makes the process more efficient, but it increases the amount of NOx formed during combustion (NOx is nitrogen oxide, a pollutant)

Because NOx is a pollutant, most modern car engines are designed to stop it from forming. This is done with EGR (exhaust gas recirculation), which pumps exhaust gases into the engine cylinder before combustion. These exhaust gases reduce power, intentionally reducing the amount of fuel and air in the cylinder in order to keep temperatures down.

So, basically, pumping hydrogenated gasoline into your engine might* increase combustion temperatures. But if it does, the EGR system on a modern car is going to respond by putting more exhaust gases into the cylinder.

*Might is the key word here, because there’s no proof of this actually occurring. Modern engines are carefully designed and tuned to maximize efficiency while keeping combustion temperatures low, so it may be that adding hydrogen to a carefully designed engine has very little impact.

So, Are Hydrogen Kits A Scam?

The short answer is maybe.

If it’s a device sold by a reputable company with supporting third party research and/or some sort of performance guarantee? If so, it’s probably legit. DynaCERT, for example, has ample evidence to support it’s claims.

If it’s a device offered by “some guy” on Amazon or eBay, with absolutely no supporting third party research? You can throw it in the scam bucket and move on.

If the kit seller promises 90% improvement in fuel economy? Forget about it. DynaCERT, for example, says that 20% is the most they’ve seen. Research suggests the average benefit is closer to a single digit percentage. So, somewhere between 5% and 20% is within reason. Anything beyond that is just beans.

Suffice to say, if you’re looking at a hydrogen kit for your car, truck, SUV, or Peterbilt, it’s a very good idea to ask for documentation, find out what the refund policy is, and check all the sources they provide.

And if the company claims more than 20% improvement in fuel economy, it’s probably a scam.