Don’t Fall for Gas-saver Scams

Devices that claim to improve engine efficiency have been around for decades. And they don’t work.

Episode Summary:

For decades, individuals and corporations have sold devices that claim to improve automotive engine efficiency. Some plug in to the car’s 12 V power outlet, and some are wired to the car’s battery, but they all have one thing in common: they don’t work. The reason they don’t work is based in physics, but despite multiple independent tests that confirm that these devices don’t work, they are still popular and are still widely sold at multiple retailers. Jim Anderton wonders why.

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Transcript of this week’s show:

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One consequence of CO2 mitigation strategies like carbon taxes is that the price of fossil fuels, especially gasoline, is increasing significantly. Broken supply chains due to Covid are also having an effect, and Americans in some states are seeing five dollar a gallon gasoline. If you drive a full-size pickup or SUV, you feel the pain, and since the OPEC oil shocks of the early ‘70s, another inevitable consequence of high fuel prices are scams. I’ve seen them my entire career, both in the automotive industry and in technical journalism, and what surprises me the most is how they relentlessly survive, decade after decade, in the face of physics and simple common sense.

So without going into the specific engineering details, let me lay it out simply: there is no such thing as an add on device that can significantly improve the fuel efficiency of your car. Period. As I’m telling you this, online retailers, auto parts stores and others are selling gadgets that plug into your car’s dashboard or are attached to your car’s battery that are claimed to significantly improve fuel mileage. And they are all scams. All of them. Some are completely ludicrous, like this one which purports to reduce the electrical load on your car’s alternator by some magical effect and improve engine efficiency.

But some do use some legitimate science. These are the electrolyzers, the devices that use 12V from the car’s electrical system to separate hydrogen and oxygen by breaking down water. They all operate in a similar way: electricity splits water into oxygen and hydrogen gas. Hydrogen gas is injected into your car’s intake system, where it is burned in the engine, recombining with atmospheric oxygen to make water vapor which flows out through the exhaust. Free fuel, right?

Except, it isn’t free. There are basic laws of thermodynamics and energy that I could describe at this point, but I’ll summarize them all with a simple statement: there is no free lunch. To make that hydrogen gas from water, it’s necessary to add about 800 kJ of energy to split up every ounce of water. When the resulting H2 gas is fed into the engine and is reacted with atmospheric oxygen gas in the combustion chamber, the process reverses and the hydrogen and oxygen gases form water, the exact opposite of the process used to break water up in the first place. And you know how much energy you get out of burning that hydrogen gas? Almost the same amount of energy that you used to make the hydrogen gas in the first place. No net gain.

And where did that energy come from? From the car’s alternator, which made that electricity from the heat energy of the engine’s combustion process. Electrolyzers take the energy away from the engine, then put it back in. It’s basic physics. They simply cannot work. Could they work? Yes, if the electrolyzer uses a different energy source to make the hydrogen gas than engine power. Solar power, a home wind turbine, a nuclear power plant, anything that is not attached to your car’s engine. Add externally made hydrogen and you will get a performance improvement. Which of course is the same as simply adding a little more gasoline to the tank.

So how do you know if you’re getting scammed? It’s simple: ask where the energy comes from to run the magic fuel saving device. If it’s powered by your car, walk away. And if the ad copy talks about oil company or government conspiracies to suppress the technology, run away.

You’re welcome.

Written by

James Anderton

Jim Anderton is the Director of Content for ENGINEERING.com. Mr. Anderton was formerly editor of Canadian Metalworking Magazine and has contributed to a wide range of print and on-line publications, including Design Engineering, Canadian Plastics, Service Station and Garage Management, Autovision, and the National Post. He also brings prior industry experience in quality and part design for a Tier One automotive supplier.