Dan Peterson
Vice President
Technical Development
Frictional losses account for big part of fuel energy inputs.
Minimizing friction in the engine and drivetrain can boost mpg.
With prices at the pump hovering around $4 a gallon and projected to hit $5 a gallon, drivers are looking for solutions to improve fuel economy through every available avenue. Concerned drivers can do a number of things to ensure optimum fuel economy, including keeping tires inflated to the correct pressure, removing excess weight from the vehicle and backing off on the accelerator. Regardless, internal combustion engines are inherently very poor for overall efficiency. With so many moving parts constantly in close contact, much of the energy input is lost in the engine and more is lost downstream in the drivetrain components.
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In fact, very little energy from fuel ever reaches the wheels to propel the vehicle. According to the U.S. Department of Energy, 62.4 percent of the fuel energy from your tank ends up as engine losses. Additionally, of the 18.2 percent of the original fuel energy that makes it to the drivetrain, 5.6 percent more is lost before it ever reaches the tires, due mostly to frictional losses.
So out of every one gallon of fuel you pump into your gas tank, 0.624 gallons disappear as heat and frictional losses, an additional 0.172 gallons is lost to idling and standby, and 0.022 gallons go to running car accessories like air conditioning. When it’s all said and done, you’re left with a mere 0.182 gallons to power the drivetrain. Of this very small amount of the starting gallon of fuel, an additional 0.056 gallons are lost to drivetrain friction, leaving only 12.6 percent of the starting gallon of fuel to turn the wheels. The remaining energy not consumed by aerodynamic drag on the vehicle body, rolling resistance of the tires, and brake losses goes to moving the vehicle. As a manufacturer of synthetic lubricants, reducing friction is a core part of most everything we do at AMSOIL. Because the combined energy losses from the engine and drivetrain use up 68 percent of every gallon of fuel, it makes sense that reducing friction by improving lubrication will have a measurable impact on overall fuel economy. So how does reducing frictional losses relate to a fuel economy improvement using this documented Department of Energy data?
If you could cut overall engine losses in the original scenario by, for example, 0.50 percent (62.4 percent to 61.9 percent), 18.7 percent of the energy would reach the drivetrain vs. 18.2 percent. If you cut losses in the drivetrain by the same 0.50 percent (5.6 percent to 5.1 percent), a total of 13.6 percent of the total fuel energy would be available to move the vehicle, compared to 12.6 percent from the original example. This results in a total fuel economy improvement of 7.9 percent. So a 2010 Ford Fusion that gets 24 mpg consistently in the city would get 25.9 mpg in this scenario by reducing frictional losses in the engine and drivetrain.
Vehicle manufacturers are and will continue to be under significant pressure to improve baseline fuel economy. In addition to implementing technologies like variable valve timing and lift, turbocharging, direct fuel injection and cylinder deactivation, vehicle manufacturers are actively looking for engine lubrication improvements to squeak out any additional fuel economy improvement possible to meet CAFE requirements. New technologies are being developed in vehicle drivetrain systems as well, including continually variable transmissions (CVTs), automated manual transmissions (AMTs), dual-clutch transmissions (DCTs) and AT step improvements, all focused on reducing the losses outlined in the example.
The constant common enemy still faced in all these technologies is friction, and synthetic technology is the main weapon to fight this battle. Synthetic oil molecules are more uniform and predictable in terms of overall performance because they are engineered to produce specific results. Conventional oil molecules are much less predictable and contain many different fractions. They are not engineered, and as a result, they do not perform as well as their highly engineered synthetic cousins. Since friction is always the enemy at AMSOIL, we continually research, formulate and validate the most advanced friction-reducing ingredients we find worldwide to create products that give consumers not only outstanding engine protection, but fuel economy improvements that leave money in their pockets to have fun on the weekends.