Environmental regulations have not been kind to the fuel efficiency of commercial vehicles. Many diesel-saving gains were sacrificed over the last decade in the name of lowering the levels of NOx and particulate matter in exhaust, as manufacturers introduced everything from exhaust gas recirculation (EGR) systems to diesel particulate filters (DPF). And even though new fuel-economy standards are expected to be unveiled next year, they will do little to support the owners of equipment on the road today.
But there are still opportunities to make a difference in the aftermarket. Jobbers already have access to a wide array of components that have a direct impact on fuel efficiency.
Wasteful idling practices, for example, can be reduced dramatically with the installation of a device like an auxiliary power unit (APU) or bunk heater. APUs are sources of every-thing from heat to cooling and electrical power, while fuel- fired bunk heaters deliver warm air while burning a fraction of the diesel that would be required by an idling engine.
The benefits do not end with the amount of fuel that needs to be consumed. According to a report by the Argonne National Laboratory, one hour of idling can cause the same amount of engine wear as 11 kilometres of driving. This may be better than the experience with older engines, thanks to the help of lower engine speeds and reduced sulphur levels in today’s diesel fuels, but it still leads to the premature engine wear that customers want to avoid.
The aftermarket even has a role to play in the aerody- namic devices that are embraced by a growing number of on-highway fleets, since many options can be added (or certainly repaired) after equipment is built.
“When driving a truck on the highway, approximately 19% of the energy in every litre of fuel burned is used to overcome aerodynamic resistance on the tractor or trailer, or the gaps between them,” notes Transport Canada. “Aerodynamic fairings can be retrofitted to the tractor (roof, bumper, tank), to the trailer (front, underside, and rear), and to the tractor-trailer gap.” A combination of more than one of these devices can reduce fuel consumption by as much as 10-15%.
Those who are recommending the different options will simply need to be aware of the potential impact on vehicle dimensions and weights, both of which are highly regulated in the trucking industry.
The choice of tires can make a difference as well. Those that offer benefits involving everything from lower rolling resistance to lighter weights can lead to fuel savings of 3% or more compared to popular options, and when used on all five axles of a typical highway tractor and tandem trailer.
Some fleets are even candidates for fuel-efficient wide- base tires that eliminate a pair of sidewalls, beads, and much of the metal found in the rims for a set of dual wheels. The amount of weight saved will depend on the equipment that was originally specified, but a shift from a set of duals on steel wheels to Michelin X-One wide singles on aluminum wheels will save about 375 pounds per axle, notes Don Baldwin, Michelin North America’s product marketing manager, commercial truck tires. About 100 to 125 pounds of weight savings will be courtesy of lower overall tire weight, while the remainder comes from the lighter wheels on which the tires are mounted.
And many earlier questions about the performance of single wide-base tires have also been answered. “People were afraid that wide-based tires would follow ruts on the road,” notes Curtis Decker, senior development engineer with Continental Tire. “That turned out not to be the case. They talk about it tracking true and being a very smooth ride.”
Any option that reduces the weight of the vehicle can play a role in reducing the amount of fuel that needs to be consumed to move it, and there is plenty of lost ground to reclaim. New exhaust-cleaning technologies such as selective catalytic reduction (SCR) systems and their tanks of diesel exhaust fluid (DEF) have added more than 300 pounds onto a truck, according to the American Trucking Associations. To compound matters, the (U. S.) National Highway Traffic Safety Administration’s pending change in stopping distances is expected to lead to the widespread use of larger brakes– introducing some additional weight of their own.
Wheels are a good place to start in the bid to shed unwanted pounds. When Alcoa launched its new LvLONE wheels, for example, it noted how it shed two pounds from its lightest 22.5-inch forged wheels, saving about 36 pounds when used on a tandem tractor with a tandem trailer. The change is more dramatic when compared to steel wheels, shedding an astonishing 648 pounds.
Then there are the potential fuel-saving weight losses associated with brake components.
“Aluminum hubs have been popular in the tractor and truck market for years,” notes Ken Kelley, vice-president of Webb Wheel Products, referring to roughly 15 pounds saved in the shift from iron to aluminum. “If you take the tanker-trailer industry, they all have aluminum wheels, aluminum hubs.”
The weight savings are not limited to aluminum, either. ArvinMeritor, for example, offers lightweight components such as stamped spiders and steel shell drums. The SteelLite X30 can reduce weight on a typical tandem axle tractor-trailer by up to 200 pounds. Meanwhile, Webb has its Vortex designs that offer lighter weights. It is still made from grey iron, but incorporates thinner walls, a centreline “squealer” band, and external ribs to assist with cooling.
Jobbers simply need to work closely with fleet customers to ensure that performance is not sacrificed in the name of weight savings.
“You can only take out so much weight or you’re going to get into trouble,” Kelley warns, referring to brake drums. “For every pound of mass you take out, you’re putting the same BTU of energy into less mass.” The result can be unwanted cracks in the face of the drum. A 16.5×7-inch rear brake should be no lighter than 100 pounds to provide a margin of safety, he suggests.
Some fuel-efficient promises can be delivered without removing any metal at all. The producers of synthetic engine oils, for example, continue to promise better fuel economy in addition to improved cold-weather cranking abilities and the chance to support programs that extend oil drain intervals.
Suppliers of these synthetic fluids tend to refer to potential fuel economy gains of at least 1% thanks to reduced friction, and the performance is even better when coupled with synthetic gear oil. Shell reported a fuel economy gain of 1.6% after running six test trucks around a track to measure the impact of various options. And last November, Valvoline introduced its “fuel-proof” guarantee that promised a positive return on the investment, even after factoring in the higher price of the lubricants.
Combined, these options promise to do more than reduce a buyer’s operating expenses. They could fuel new business opportunities for jobbers who deliver the goods.