Fuel Economy in a Bottle?
Motor carriers will spend an unprecedented $85 billion on fuel this year – a $23 billion increase over 2004, predicts the American Trucking Associations.
One result of high fuel prices has been increased marketing of fuel additives and devices that claim to improve fuel economy.
"I think there's an excellent opportunity for less than scrupulous people to come in and do things in the name of trying to help," says Chris Greeson, senior technical services manager for Wix filters.
There are plenty of fuel additives that are legitimate, useful and even necessary. For instance, much of the diesel fuel commercially available in the market already has a lubricity additive included to meet specifications for lubricating properties of diesel.
Other types of additives include injector detergents, cold flow improvers, anti-foam additives, anti-oxidants, biocides, etc. These additives can be used individually or combined into multifunctional additive packages.
Detergent additives can offer a fuel economy benefit, but it won't be immediate, says K.W. Gardner, fuels quality manager at ExxonMobil. "Those have been documented to improve fuel economy over time," he says. "Basically they operate by cleaning up deposits on the injectors, which improves combustion efficiency, and they've been shown to improve fuel economy 1.5 percent to 3 percent. It doesn't give you an immediate benefit; it takes time to clean up those type of deposits."
"A certain amount of caution needs to be exercised before getting too carried away with the use of any aftermarket additive," says Gary Parsons, global OEM and industry liaison manager for Chevron Oronite, "In general, additives can be viewed in the same vein as medicine. When used at the right dosage in the right applications, they can serve their desired purpose. However, used at improper dosages or in the wrong combinations, the side effects can be detrimental and defeat the purpose for using them in the first place."
Matt Stein, lead engineer, engine liquid filtration for Donaldson, also notes that when you change the properties of the fuel with improper additive usage or alternative fuels, you could get unanticipated effects on components such as gaskets, or hot or cold weather issues that you didn't anticipate.
Another type of additive you may see marketed is stability additives. Fuel experts we spoke with said they really aren't needed. Stability additives are put into the fuel at the refinery, says ExxonMobil's Gardner, and subsequent use has little value.
"With today's high diesel fuel throughput rates, fuel aging and stability is not usually an issue and supplemental additives are not required," says Parsons.
Don't be tempted to try lower-cost fuel alternatives, such as burning used crankcase oil in the engine. Unless the engine OEM has recommended it, and specific procedures are followed, any short-term financial gains could be offset by premature equipment failures and operational problems. These fuel extenders or alternative fuels also may have higher levels of contaminants, which will plug fuel filters or significantly reduce the useful life of the filter.
You also may be tempted by various devices that claim to improve fuel economy.
"During times of high fuel prices, a whole host of mechanical or "miracle" type devices enter the market as people get more desperate to improve fuel economy," Parsons says. "Most of these devices don't have any scientific basis for the claims that are being made."
Keith Bechtum, engine liquid filtration product specialist at Donaldson, recommends, "Whenever you look at a product like that, make sure the manufacturer stands behind their warranty claims. Do they have anything more than a testimonial, and will they guarantee that performance?"
Bechtum is skeptical of most devices claiming to improve fuel economy. "The engine OEMs are in constant competition with one another," he says. "If any of these guys could put something on their engine for $100 that improved fuel economy to any significant impact, don't you think they would do it?"
When evaluating anything that says it will improve your fuel economy, Gardner recommends looking for documented, extensive testing in real-world situations. "Documenting fuel economy on the basis of a single or very few engine tests just isn't scientifically sound," he says. "Fuel economy can vary an awful lot from tank to tank, from driving condition to driving condition, from engine to engine. You need to do a very sound, controlled experiment to document a fuel economy claim."
When he's seen it done well, he says, a large fleet typically runs the fuel-saving device, additive or technology on half of its trucks for a certain period of time, using the other half as a control. Then halfway through the test, the trucks being used are switched in order to make sure factors such as driving skills, routes and the like aren't affecting the results.
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