DETROIT - Improve fuel economy - type those words on Google, and you'll get more than 23.4 million Web pages on the subject.
Look closely. You'll also see an abundance of atomizers, magnets, fluids for crankcases and fuel tank additives. Never mind that, as one Web site puts it, some products are "beyond the understanding and acceptance of modern science."
Some products use magnets on fuel lines, air cleaners or other car parts, claiming that magnetic energy changes fuel molecule polarity, which results in better mileage. Others install air bleed lines, fuel "atomizing" devices or other mechanical parts meant to change air-fuel flow into the engine. Another family of economizers includes liquid or pill additives. They're meant to be mixed with fuel or with crankcase oil to decrease friction and improve economy.
But many such products have been discredited for years.
General Motors doesn't put magnets on the fuel lines of its new cars. There's no reason to, says Dave Lancaster, group manager of GM Powertrain.
"We do a lot in order to try and optimize the efficiency of our products," Lancaster, who also is chairman of the Detroit section of the Society of Automotive Engineers, told Automotive News. "Believe me, if we know of something that will really help, we'll use it,"
Modern vehicles using fuel injection, sensors and electronic engine controls are able to adjust themselves constantly to use fuel as efficiently as possible. Systems such as variable valve timing and cylinder deactivation, meanwhile, are able to save seemingly low percentages of fuel - about 2 to 3 percent for variable valve timing, according to national studies, and 8 percent for cylinder deactivation, according to GM. But such gains add up over time.
Drivers may have the idea that an add-on product could help them save because of misapprehensions about old-time carburetor-based systems, when the flow of air and fuel to cylinders wasn't always consistent and when engine control systems were more primitive. In those days, it was difficult to prove that an invention meant to bleed extra air into the fuel mix wasn't doing any good.
"Remember as a kid growing up, you'd get in the car, pump the throttle, set the choke, maybe pump it again to get it started," Lancaster says. "Think about driving along in traffic and what it smelled like."
Today's fuel and lubricants are made with specific additives. Engines are built to last for well over 100,000 miles. Tacking on any device may destroy the advantages that engineers have worked to gain for the vehicle.
Bob Olree, an expert on engine lubrication at GM, says the latest new standards for oil formulations gained 0.2 percent in fuel efficiency. Oils must meet an International Lubricants Standards and Approval Committee designation, which is then licensed to refiners by the American Petroleum Institute.
No additives, please
Engine oil is really a near-synthetic bath that contains detergents to reduce engine deposits. It contains chemicals to keep engine parts from wearing, dispersants to keep sludge from forming, antioxidants to keep the oil from thickening and viscosity modifiers.
"It's a highly engineered product," Olree notes. "We caution in our owner's manual against adding anything to the oil, period, other than just some more oil. We've said for years that we do not suggest anybody use any additive system. Period."
Gasoline, too, comes with its own set of specific additives. These are primarily detergents meant to keep injectors and cylinders from forming carbon deposits.
Andy Buczynsky, senior engineer for fuels at GM Powertrain, says the intent is for fuel to leave a thin film on engine surfaces to prevent chemical buildups. While fuel additives may offer extra detergents and anti-knock compounds, they're generally just stronger concentrations of existing additives, he says.
"Our stance has always been that the gasoline coming out of the pump is fully additized," he says.
EPA rules require that gasoline contain a certain amount of detergent additive to keep pollution control systems running correctly.
Most don't work
The EPA has tested more than 100 devices that claim to boost fuel economy, according to the Federal Trade Commission.
Of those, investigators have found that a handful make a tiny difference in improved mileage, sometimes at the cost of increasing exhaust emissions. Two are "driving-habit modification" devices that light up or make a sound to tell a driver to lighten up on the accelerator or shift gears. Three reduce the engine power used for belt-driven accessories. Two are cylinder deactivation systems, and one is a spoiler that changes the air flow under the car.
"No government agency endorses gas-saving products for cars," warns the FTC's Web site.
FTC spokeswoman Claudia Bourne Farrell says there is no way of knowing how many fuel economy product complaints have come to the agency since fuel prices spiked last year. But, she says, over the years the FTC has prosecuted "lots" of fuel-related cases.
One such case, a settlement of a lawsuit by the FTC in May 2005 against online marketers of a product called Super FuelMAX, was typical.
The Super FuelMAX device was a magnet meant to be clamped onto the fuel line. Marketers claimed that fuel would burn more efficiently due to "magnetic resonance."
"A certified EPA laboratory reports an amazing 27 percent in increased mileage and 42 percent reduction in harmful pollutants," was among the claims the FTC found fraudulent and unsubstantiated.
But the most the FTC was able to do was to get the marketers to agree to stop making unsubstantiated claims after the commission determined the marketers had no money to pay fines of almost $300,000.
As a rule, engineering and enforcement experts warn, one of the oldest rules remains: If something looks too good to be true, it probably does not work. Says Lancaster, the GM engineer: "There's only so much energy to get out of a gallon of gas."