Getting The Best Fuel Economy
Simply put, a truck
requires energy to move along and overcome resistance — mechanical,
air and rolling — to forward motion. The truck’s engine
converts the energy stored in fuelinto mechanical energy used to drive
the truck. Some of this work energy is lost in the engine, drivetrain,
accessories, wheel bearings, and so on, through mechanical resistance.
Air resistance is caused by the movement of a truck
through the air. The greater the speed of the truck and the less
aerodynamic its shape, the greater the air resistance. Environmental
factors, such as wind and weather, also impact “aerodynamic
Rolling resistance is caused by the interaction of the
tires and the road surface. The amount of rolling resistance depends on the
weight and speed of the truck, type of road surface and the design, tread
pattern, inflation pressure and condition of the truck’s tires.
There are a variety of factors that impact fuel
economy because of their influence on resistance. These include:
Vehicle: The more aerodynamically sleek the design, the less the air
resistance. Consider using aerodynamic treatments such as chassis and roof
fairings, cab extenders, aerodynamic mirrors and moving equipment out of
the air stream.
and application: Loads, speed, routes, traffic,
terrain, road surfaces, empty miles and weather all affect fuel
consumption. Consider using software programs to assist with boosting fuel
economy, as well as productivity and efficiency, through improved
inbound/outbound planning, computerized mapping and route optimization,
detailed driving directions, and so forth. Telematics can be used to
provide driver and vehicle utilization and productivity data. Digital fuel
consumption gauges can be used to provide the driver with real-time
feedback on fuel economy.
Maintenance practices: The
better a truck is maintained, the more efficiently it will operate. That
translates into improved fuel mileage and more uptime.
Tires: Tire selection impacts a vehicle’s overall fuel
performance, and therefore, should be application specific. Tread depth and
design, construction, size, inflation pressure and condition each have an
effect on rolling resistance. It is always advisable to consult with a
truck tire specialist before making tire purchases, whether new or
The single most critical factor for getting the most
out of tires is to maintain proper inflation pressure for a given tire size
and load. Because an improperly inflated tire doesn’t roll as
smoothly or as easily as it was designed to, rolling resistance and wear is
increased and fuel economy is adversely impacted, as is handling, traction,
braking and load carrying capability.
Drivers: No matter how
advanced fuel-saving devices may be, they will not achieve optimum results
unless they are used with sensible driving practices. These include
starting at the slowest engine speed that will move the load; using the
minimum rpm, minimum power and fewest shifts necessary when accelerating;
running the engine in its peak torque range; using cruise control; using an
engine brake; minimizing idling; and accelerating or decelerating well in
advance of a stop or a need to speed up.
Excessive vehicle speed has the biggest impact on
reducing fuel mileage. Industry studies have found that for every one mile
per hour increase in speed over 55 mph, there is a 2 percent loss in miles
per gallon. At the same time, higher speeds also increase engine, vehicle
and tire wear, leading to higher maintenance costs.
The ideal time to start saving fuel is at equipment
acquisition. First, decide upon your fuel economy expectations and
requirements for your vehicles. Next, review your current and previous
equipment specs to see which have been effective in maximizing miles per
gallon. Then, visit with vehicle and component manufacturers to go over
this material and to learn about the latest advances and new products and
components for fuel economy.
Knowing how to squeeze more miles from each tank of
fuel will help reduce operating costs and improve your profitability.
Fuel economy ‘affecters’
Some of the factors that have the most impact on fuel
Electronic vs. mechanical engines
Rib tires in every wheel position
Roof fairing vs. flat roof
Source: Study by The Technology and Maintenance
David Kolman is a veteran truck communicator, keynote
speaker and long-haul trucker. Commissioned as an Honorary Colonel on the
Kentucky governor’s staff for his work promoting traffic safety, he
actively participates in trade associations and reports news and
information about the trucking industry for broadcasting and print media.
Equipment news round-up
DaimlerChrysler and Freightliner Market Development
have teamed to offer MileMinder, a used-truck contract maintenance program
with a guaranteed cost-per-mile agreement. The maintenance package includes
all mechanical repairs, preventive maintenance, tire repairs and
replacement and roadside services. The program, available for leased or
purchased vehicles financed through DaimlerChrysler Services Truck Finance,
is offered through participating SelecTrucks Centers and Freightliner,
Sterling and Western Star dealers.
Hendrickson has introduced its HTB rear air suspension, “a
premium, improved-riding alternative to industry standard
suspensions” for Class 8 trucks. A low-maintenance, lightweight,
non-torque reactive suspension, it is said to be the lightest suspension in
its class at 570 pounds including axle brackets, which saves up to 257
pounds of weight over industry-standard 40,000-pound suspensions.
Peterbilt is making detailed
truck schematics and parts lists available through
the Internet with its TruckCare Web ECAT (electronic catalog). Replacing
the CD-ROM version, Web ECAT cross references a truck’s original
chassis record with the PACCAR Parts catalog. Users can search and identify
parts by keyword, part number and interactive visual diagrams.
Additionally, wiring and air piping diagrams, as well as alternate part
selections if the original part is no longer produced, are available.
Roadranger has a new four-disk CD set that neatly packages more than
400 Dana and Eaton product and service
documents, providing a comprehensive Roadranger product library. The CD set
includes such key information as driver training, lubrication tips,
troubleshooting guidelines, illustrated parts lists and warranty
information. Components and systems that are featured include axles,
brakes, clutches, driveshafts, trailer suspensions, tire management
products, manual and automated transmissions, service tools and collision