Kenworth white paper details efficient economical vehicle operation

Jan. 1, 2009
Kenworth Truck Company, Kirkland, Washington, has produced the Kenworth White Paper on Fuel Economy to help meet the challenges of today's diesel prices

Kenworth Truck Company, Kirkland, Washington, has produced the Kenworth White Paper on Fuel Economy to help meet the challenges of today's diesel prices and operating costs.

The publication, available as a PDF file for electronic download and printing on Kenworth's Web site at, features detailed sections on aerodynamics, component spec'ing, route and idle management, driver behavior, proper maintenance, and advanced technology to assist truck operators in their efforts to increase fuel economy and manage operating costs.

“Fuel efficiency, and finding ways to increase it, is foremost on the minds of fleets and owner-operators today,” said Gary Moore, Kenworth assistant general manager for marketing and sales. “The Kenworth White Paper on Fuel Economy provides very useful information that can help pay dividends in the drive to enhance fuel efficiency and reduce operating costs.”

Approximately half the energy used by a truck traveling 55 miles per hour is simply to move the air around that truck. At 65 miles per hour, about two-thirds of the energy is used to cut through the air, the paper noted. Other cost-saving opportunities include:

  • A vehicle's basic specifications and options can have a significant impact on fuel use.

  • Select a sleeper package appropriate for the trailers being handled by the truck.

  • Aerodynamic treatments to the trailer will also enhance fuel economy performance.

  • The use of underhood-mounted air cleaners — not cowl-mounted air cleaners — can improve aerodynamics by 2% to 4%.

Other considerations listed in the paper include wheelbase and fifthwheel settings, properly sized components, and tire and wheel specifications. “Tread depth over the life of a tire has a significant effect on tire fuel economy,” the paper noted. “As a tread wears, the fuel efficiency of the tire usually increases.”

Kenworth recommended using the Environmental Protection Agency's SmartWay program when selecting tires for fuel economy. The complete list of SmartWay approved tires can be found online at

Kenworth also recommends selecting the right engine and gearing for the intended operation. “Size the engine for the job,” the paper said. “Spend time with the engine manufacturer to customize engine parameters to the company's operation.”

At the same time, selecting a powertrain that meets the individual application is very important to optimizing fuel economy. “Be sure to check with the engine supplier to obtain the characteristics of the sweet spot, which can vary widely,” the paper suggested.

Kenworth also suggested spec'ing an automated transmission in order to enhance fuel economy through computer-controlled shift logic.

For drivers, the company recommended a cab display to give the average and instantaneous trip mileage feedback, as well as many other insights to trip, performance, and driver reward status. “A boost gauge should be added as a minimum requirement,” the company said.

Another way to increase operation efficiency is by improving route management. “This can be easier said than done because even veteran truck drivers may sometimes have trouble finding a delivery location,” the paper stated. “Some companies and drivers make many deliveries to new locations — especially on backhauls. Searching for a customer's location can add stress to driving. Out-of-route miles and lost time can result if a driver misses a turn, impacting on-time delivery.”

Idle management also plays a significant role in overall fuel economy. Unnecessary idling can result in substantial cost to the owner. Kenworth recommends its Kenworth Clean Power System that provides heating, cooling, and hotel load power for up to 10 hours. The system uses stored energy for cooling and hotel load power rather than running a diesel engine. The Clean Power System fuel savings versus typical fuel consumption from idling the truck or running a diesel APU can really add up, according to Kenworth.

Another way to increase efficiency is to reduce excessive speed, which “is the largest single factor in reduced fuel mileage,” the paper stated.

Other driver-controlled improvements include using restraint when accelerating from stop. “Different engine models operate differently, so be sure to read your owner and driver manuals to achieve the best performance from your engine,” the information noted.

Proper maintenance also is important in the fuel economy equation. The white paper recommends several things to remember when setting up a new truck engine parameters.

“Replace air and fuel filters at the proper intervals,” the company said. Watch your boost gauge at full load and consistent elevations. A reduction of boost could indicate a leak in your charge air system.”

Another important element is monitoring fuel quality at the pump to reduce injector clogging or spray pattern disruption.

Keeping the truck body in repair also is essential to increase airflow efficiency.

Use a good synthetic or semi-synthetic oil in the engine and drive axles, the paper recommends. “Also use a good synthetic transmission fluid” the information states. “Kenworth uses synthetic oil in the axles and transmissions of new trucks coming off the production line. Don't use a higher viscosity oil than actually needed for the operating conditions.”

For more information about improving operation efficiency, visit the Kenworth Web site at The white paper also is available from Kenworth dealers.