1. Buy higher-mpg vehicles
When federal emissions regulations for commercial trucks switched from focusing on PM and NOx to greenhouse gas emissions, it meant the fuel efficiency of new trucks rose with the 2014 regulations.
Lighter-duty vehicles, too, are becoming more fuel-efficient. Crunch the numbers to see what the payback would be of buying a new model.
If you can’t afford new, sometimes a glider-kitted truck with an older, “pre-emission” diesel will deliver good fuel economy, too.
2. Spec aerodynamic trucks
There are big savings to be had by paying attention to how your vehicle glides through the air.
For instance, wind tunnel testing has resulted in re-shaped mirrors, antennas that are integrated into the cab, and elongating side extenders to redirect airflow around the Cascadia Evolution, according to Freightliner. Paccar upped the game on its aerodynamic models this year with the Kenworth T680 Advantage and the Peterbilt Epiq package for the Model 579. Navistar has its ProStar, Mack the Pinnacle Axle-Back, and Volvo the VNL and VNM.
3. Make engine and transmission work as a team
Consider both the experience level of your drivers and vehicle application when spec’ing your truck, says Navistar. This will help you select the most fuel-efficient transmission and engine pairing for your application.
Volvo, Mack, and Daimler Trucks North America all offer fuel-saving integrated powertrains featuring automated manual transmissions, and Cummins and Eaton have teamed up to offer the same type of benefits with the Cummins-Eaton SmartAdvantage product, available from several truck builders.
4. Consider aero fairing options
A cab with chassis side fairings can add up to 3% to fuel economy and cab side extenders add up to another 3%, says Freightliner in its forthcoming white paper on real cost of ownership.
5. Move away from manuals
The addition of an automated transmission (such as Allison’s TC10, Detroit’s DT12, the Eaton UltraShift, Mack’s mShift or the Volvo I-Shift) provides consistent and precise shift points to increase fuel economy in the engine rpm sweet spot.
An excellent fuel-miser driver may be able to beat an automated transmission on his best days, but AMTs provide a level of consistency that saves fuel day in and day out.
“Everyone drives a truck differently, and the fuel economy range between a fleet’s top driver and lowest performer can exceed 1 mpg,” says Kevin Baney, Kenworth chief engineer, speaking about the Eaton Fuller Advantage automated manual in the Kenworth T680. “This transmission reduces this variability. Imagine the best drivers in your fleet, and cloning their shifting performance.”
6. Right-size the engine
Engine displacement as well as torque and horsepower requirements should be carefully considered, as more than one combination may work for you. Resist overspec’ing in size and power except in harsh environments where extra durability could be to your advantage.
For many fleets, a smaller 13-liter diesel saves weight over a 15-liter but still offers plenty of horsepower.
More and more engines are being designed for “downspeeding,” where the components work together to lower engine rpm at a cruising speed.
7. Spec for the sweet spot
Choose gearing options and tire sizes carefully to match the engine’s sweet spot with your road speed parameters. Consider the application, for instance, mostly Interstate versus rural two-lane highway. Where will the truck run most of its miles? Power and gear the truck for where it will spend most of its time.
8. Fine-tune your engine settings
The engine’s electronic control module settings have a measurable effect on fuel economy, says FleetAdvantage in its white paper, “Leveraging Big Data to Maximize Fuel Economy.”
“Most companies order their equipment without requesting specific ECM settings to optimize fuel economy. The equipment is delivered with factory settings with no consideration given to the actual duty cycle of the equipment. This is analogous to not setting your preferences on your computer or smartphone — the phone works fine but it is not tailored to the user or the application.”
For instance, notes Kenworth, engine software can be programmed to encourage drivers to up-shift at lower rpms by reducing power (soft limit) — or, it can encourage drivers to drive in top gear by limiting the rpm in the one gear below top gear (hard limit).
9. Spec a variable-speed fan clutch
Engine cooling fans don’t work all the time because that would waste energy. So there are options to match fan operation to the actual needs of the engine. Instead of the basic on/off fan clutch, there are two- and three-speed drives, plus variable-speed drives that are controlled by the engine’s electronic control module to provide more precise fan speeds. In testing by BorgWarner, on/off fan drives used 0.8% of an engine’s energy, while variable speed fan drives used only 0.3%. And unlike a lot of aerodynamic changes, this is an idea that works well for vocational trucks or pickup and delivery operations, because they have more on-fan time, explained Vince Ursini with Behr America at a 2011 Technology & Maintenance Council session on this topic
10. Match cab and trailer size
Matching the cab height and width to the trailer can add 10% to fuel efficiency, Freightliner says.
According to the Technology & Maintenance Council, you will save up to 15% in fuel consumption if you operate a truck with a full-cab roof fairing — one that matches the height of the trailer. If you pull a low-height trailer, like a tanker, grain hauler, or flatbed, consider spec’ing a flat-roof or mid-roof sleeper instead of a high-roof sleeper, which would likely add resistance.
11. Close the gap
Mesilla Valley Transportation, known for pioneering fuel-saving specs, realized early on that minimizing the gap between tractor and trailer was a critical piece of fuel economy, so in 1985 it put in a fixed fifth wheel and, over time, have reduced that gap further. If you shorten the gap between the trailer and the tractor by 18 inches, from 60 inches to 42, you can increase fuel economy by 1–2%, according to PacLease.
12. Even mudflaps matter
Some fleets find mudflaps with flow-through air design, such as Eco-Flaps, Spraydown and V-Flap, improve efficiency and also minimize water spray.
Mesilla Valley had switched to wide-base single tires and wheels, and realized that standard mudflaps were then wider than necessary. It figured narrower mudflaps would streamline airflow, so started cutting them down in 2010.
13. Spec a 6x2 tandem
In a tractor with a 6×2 configuration, only two of six wheel positions are powered, rather than the usual four. The second tandem axle is sometimes referred to as a “dead” axle, because it carries load but doesn’t help propel the vehicle.
Using an automatic load transfer system helps maintain traction by switching weight from the dead axle to the driven axle. The 6x2 eliminates the rear-rear differential and inter-axle driveshaft, saving weight and reducing parasitic loss from the drivetrain.
The 6x2 configuration can save highway truck operators an average of 2.5% in fuel compared to the dual-drive 6x4 that currently dominates the market, according to a study by the North American Council for Freight Efficiency.
The study, which involved axle and truck manufacturers and five large fleets, also found that fuel savings would pay back the costs involved with acquiring the more expensive 6x2 systems in about 20 months.
Although 6x2s have been used in Europe for some time, they’re rare here. With the increased interest in using them for fuel economy, manufacturers have been introducing more sophisticated and even lighter weight options, including Dana’s Spicer EconoTrek tandem axle, Hendrickson’s new Optimaax, and Meritor’s FueLite and SmarTandem.
14. Spec for lighter weight
Lightweight components will ultimately save fuel, but they tend to be expensive at the outset and may not be as robust as heavier parts. Wide-base single tires, aluminum wheels, and 6x2 drive axles, for example, offer substantial weight savings. There are many aluminum options to consider, including aluminum transmissions cases.
Another idea is spec’ing a smaller fuel tank if your operation allows for it. Diesel fuel weighs around 7 pounds per gallon, so carrying 20 fewer gallons saves 140 pounds. A smaller tank by itself also saves some weight, but just pumping fewer gallons into an existing tank reduces poundage.
Some fleets have gone so far as to eliminate the passenger seat. And chrome accessories may look sharp, but they can add weight.
15. Roll on aluminum wheels
The race is on to see who can come up with the lightest truck wheels. Alcoa developed a new aluminum wheel alloy and says its 22.5-inch by 14-inch wide-base wheels are now 54 pounds each, and 22.5-inch by 9-inch wheels are now 51 or 59 pounds, depending on fitment. Switching from a comparable steel wheel to Alcoa aluminum 9-inch wheels saves more than 50 pounds per wheel, the company says.
Meanwhile, Accuride’s new Accu-Lite 22.5 x 14.00 2-inch outset wheel weighs 56 pounds, while the 0.50-inch outset version weighs just 55 pounds.
16. Cover those wheel hubs
Wheel covers adorn the WAVE concept truck unveiled recently by Walmart, but unlike some of the technologies on that truck, these are available now, including brands such as Deflecktor, FlowBelow, RealWheels’ Aerostyle, and Solus. Schneider uses fabric wheel covers on its drive position tires. Truck makers are including them as standard or options on their most fuel-efficient models, such as the Freightliner Cascadia Evolution and Kenworth’s T680 Advantage.
17. Use on-board scales
Most truckers probably think of using onboard scales in order to avoid overweight tickets, but they also can be a fleet fuel savings strategy, says Bob Zirlin, director of sales and marketing for Air-Weigh. “Fleets significantly reduce fuel consumption by not overloading, maximizing payload, and reducing out-of-route miles,” he says.
“It’s a 30-40 mile trip to the nearest scale, and we load many times a day, so Air-Weigh has already paid for itself in out-of-route miles alone,” says Gary Richard, Fleet Manager for Murphy Brown LLC, Warsaw, N.C.
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