How can electricity increase my car's fuel efficiency?

Is there a way to make our cars more efficient without scrapping the whole engine?
Is there a way to make our cars more efficient without scrapping the whole engine?
Reza Estakhrian/Taxi/­Getty Images

For decades, scientists have been working to increase the efficiency of internal combustion engines. From pollution and energy-dependence standpoints, hydrogen and electricity are far preferable energy sources than gasoline, but they require completely new engines. Those new engines are expensive -- and they'll require new cars, which are even more expensive. But if we could increase the efficiency of current engines by simply adding a part to the process, that would be a good first step toward saving the planet and our money.

You might be surprised to know there are such parts on the market. A relatively popular one uses magnetism. The idea behind that add-on device is that applying a magnetic field to fuel alters its electrical properties, and that alteration increases fuel efficiency and horsepower by 10 to 20 percent. This magnetic piece is clamped to the outside of the fuel line to apply the field before the fuel is injected into the engine for combustion. So why don't we all have these magnets in our cars? Because there's a lack of hard evidence that the concept works [source: Powell].


­Other devices are more reliably effective, but more difficult to install. For instance, you can apply an electrostatic charge to the fuel at the nozzle of the fuel injector. The electrostatic charge reduces the viscosity of the fuel by causing all of the fuel atoms to take on a negative charge. The atoms then repel each other, and the fuel becomes thinner in consistency. The fuel breaks up into smaller particles when the fuel injector spits it out, and smaller particles burn more co­mpletely. This theory is well-received in the scientific community. The problem is, this approach requires a completely different fuel injector than what is currently built into car engines. The same goes for a device that reduces fuel viscosity by applying greater pressure to the fuel. This also requires a new type of injector. It's not a simple replacement.

­Recent research, though, has applied a similar principle in a way that's easier to implement in our engines. It uses electricity, too, but applies it in a different way. In this article, we'll find out what scientists have discovered about fuel and how much the discovery could improve the fuel efficiency of our cars. The innovation relies on something called electrorheology.



Electrorheology: Charge It

Applying electricity to fuel can reduce its viscosity.
Applying electricity to fuel can reduce its viscosity.
Jeffrey Coolidge/Iconica/­Getty Images

­Rheology is the study of how fluids -- usually liquids -- flow in response to certain stimuli. Electrorheology studies how fluids react to applied electricity. In the case of an invention out of Temple University, introduced in September 2008, the fluid is fossil fuel.

The innovation relies on what's actually a fairly new physics principle -- that applying electricity to fuel can reduce its viscosity not only by imparting negative charges, but also by altering the position of fuel molecules [source: Tao]. In the new invention, this second effect is more important than the first.


The electrorheological theory at work goes something like this: When you zap fuel with electricity, the molecules tend to realign. But fuel is made up of lots of different types of molecules, and the different types respond differently to the voltage. Larger molecules group together into little bunches, while smaller particles don't cluster as much. The result is a less viscous fluid, because the largest molecules are more spread out. Thinner fuel breaks up into a finer mist when it hits the injector nozzle.

Why is this so important? First, because the smaller the injected fuel particles, the more surface area comes into direct contact with oxygen. The particles burn more completely, allowing the engine to create more energy out of each serving of fuel. Second, it reduces the amount of pollution pouring out of our cars, because most harmful emissions result from the fuel not burning completely [source: Tao].

The big deal about this invention is how easy it would be to add it to our cars. The voltage, 1 kV/mm, is applied within the fuel injector by two pieces of metallic mesh, one positively charged, the other negatively, spaced 1 centimeter apart [source: GCC]. The pieces of mesh can simply be inserted into an existing fuel injector, positioned before the fuel hits the nozzle. The cost, then, would be relatively low. The other big plus is that it uses very little power to create the voltage, so it doesn't detract much from the car's battery.

So we can pop this into our cars without too much trouble. But how much improvement are we looking at? It's pretty significant, up to a 20 percent jump in fuel efficiency when tested on a diesel-fuel engine. Researchers have found up to a 15 percent increase on regular gasoline [source: Tao].

For such a recent development, it looks like we might not be waiting too long for a chance to try it out. The Temple researchers have already leased the patent to Save the World Inc. The people at Save the World are working on development, with plans to mass-test the part in conjunction with a Pennsylvania-based trucking company. They're expecting a fuel-efficiency increase of up to 12 percent, which could have the added benefit of lowering the prices of all the stuff those trucks carry to a store near you [source: ScienceDaily].

­For lots more information on electrorheology, fuel efficiency, car engines and related topics, look over the links on the next page.


Lots More Information

Related HowStuffWorks Articles

More Great Links


  • Powell, Mike R. Magnetic Water and Fuel Treatment: Myth, Magic, or Mainstream Science? Health Education Alliance for Life and Longevity.
  • Reality Check - A New Fuel Saving Device. New Energy and Fuel. Oct. 1, 2008. /reality-check-%E2%80%93-a-new-fuel-saving-device/
  • Researchers Find That Fuel Line Electrorheological Device Can Boost Fuel Economy. Green Car Congress. Sept. 24, 2008.
  • Tao, R, et al. Electrorheology Leads to Efficient Combustion. Energy and Fuels. Sept.12, 2008.
  • Want Better Mileage? Simple Device Which Uses Electrical Field Could Boost Gas Efficiency Up To 20%. ScienceDaily. Sept. 26, 2008.