Driving Skills for a Smaller Fuel Bill

iStock_000008984856XSmallCarlos Cruz, a struggling lease-operator, was ready to turn in his keys after a few months on the road. But as a last-ditch effort, he decided that on this final trip to the terminal, he’d follow all the advice about fuel efficiency he’d been hearing from trucking business gurus and see if it allowed him to recoup expenses and increase his take-home pay.

The experiment was a success, so much so that he decided to give his business another month. After 30 days his fuel mileage went from the 6.2 to 7.8 miles per gallon, a 1.6 mpg improvement that more than quadrupled his net revenue.

That was three years ago. Today Carlos continues his lease deal and can afford to live well on his income.

Details of his story are in Jim Park’s column on TruckingInfo.com, but the three habits he says make the biggest difference are:

  • Slowing down from 65 to 55 mph
  • Never idling
  • Becoming a “progressive shifting machine.”

He also says he’s forgotten where the cruise control switch is, although other fuel efficiency experts say cruise control has its place.

For example, Detroit Diesel application engineer Chuck Blake points out in this article that cruise control gives drivers a break from active driving and may be a tad more efficient on flat roads. “A really good driver can always out-perform cruise control,” he says, “but it’s tough and it’s tiring because you’re always working.”

On the other hand, the electronic control module (ECM) is not as good at telling the difference between a hill and a headwind, Blake says. All it knows is that some external force is slowing the truck down, and it’s going to feed as much fuel to the engine as it needs to maintain the set roadspeed.

A fuel-efficient driver lightens up on the gas pedal when full power isn’t needed, like when cresting a hill. “He can see the top of the hill, and backs off the throttle as he goes over the top”, Blake says. “Sure, he gives up a few miles per hour, but the fuel savings is phenomenal.”

Running full throttle to the top of a hill means wasted fuel when you’ll only need to apply the brakes as you descend the other side. “Kick it out of cruise as you near the top, and let gravity help you,” he says. “You’ll make up the lost road speed quickly enough on the way down.”

On Land Line magazine’s website, an article on lead foot rehab says fuel efficiency starts with a visit to a reputable shop where they can check the ECM for valuable stats that help you most effectively modify your driving technique. Look for data about engine RPM, time in gear, idle time, percent fuel use, fuel used idling, load factors, PTO time, PTO fuel used, speed vs. rpm, and engine load vs. rpm. The stats may also point to programming tweaks that will help reduce fuel consumption.

Overdrive.com’s 67 Fuel Tips to Boost Fuel Economy recommends more good driving habits:

  • Avoid revving the engine between shifts. Ease into each new gear, and don’t be in a hurry to climb through them.
  • Adjust shifting patterns. Download engine data to compare your shifting behaviors – RPMs at shift point – to the optimal RPM “torque bands” for your engine. Adjusting your shifting to fit the make and model of engine can make a big difference. Every 1,000-RPM reduction in engine speed delivers a 1 percent gain in fuel economy.
  • Run in your engine’s “sweet spot.” Once you reach cruising speed, operating in the peak torque zone gives you optimum horsepower, so the engine runs most efficiently. It takes only about 200 horsepower to maintain 65 mph.
  • Lower your average highway speed. Every MPH over 55 equals a 0.1-MPG drop in fuel economy.
  • Anticipate traffic signals. If you can approach slowly and avoid a complete stop, it saves fuel and reduces equipment wear.
  • Minimize AC use. Running the air conditioner delivers a 2⁄10 to 4⁄10-MPG hit. (However, some efficiency experts say that, over 55 MPH, the drag created by open windows hurts mileage more than the AC.)
  • Use truckstops atop hills. Driving uphill toward the truckstop allows natural deceleration, and going downhill to re-enter the highway requires less fuel.

Besides driving habits, dozens of other factors impact mileage. Overdrive’s 67 tips article will give you many more ideas. Also see Caterpillar’s Tractor-Trailer Performance Guide for an even more thorough guide to troubleshooting aerodynamic issues, route selection, tires, gearing, transmission, engine cooling requirements and more.