By Suzanne Stempinski, field editor
Remember when good mileage was pushing 5 mpg? And trucks ran down the road flat out, wide open, and fuel economy meant making sure you had just enough left in a tank to get across the next scale before you put on another 50 gallons so you could stuff a few more high-dollar boxes on the back? And putting out smoke didn't mean there was a fire anywhere other than in your belly to make a little more money to bring home.
Well, those days are done.
Trucks run cleaner, leaner and cost a lot more money to buy and maintain. So you can't just run harder; you've got to be spec'ing smarter, because the sweet spot just got a little smaller.
Volvo Trucks North America has introduced a powertrain package for its VN series tractors aimed at reducing fuel consumption. The new XE13 – exceptional efficiency – powertrain package lowers engine rpm at a given vehicle speed, a concept Volvo calls "downspeeding."
The combination of Volvo's I-Shift automated manual transmission and a Volvo engine with modified software, XE13 allows the engine to cruise at just 1,150 rpm at 65 mph – about 200 rpm less than the average truck sold today.
"Historically, we've seen a slow progression toward a lower 'sweet spot,' with the 1,300 to 1,500 rpm range as the current industry standard," Ed Saxman, Volvo Trucks product manager – powertrain, said.
"The engine with the XE13 package has a 'sweet spot' of 1,050 to 1,500 rpm. Customers gain about a 1.5 percent fuel efficiency improvement for every 100 rpm of 'downspeeding,' so fleets that spec XE13 can expect up to a 3 percent improvement when compared to another overdrive transmission in a similar operation."
On a cloudy morning with showers in the forecast, we left the Volvo Powertrain plant in Hagerstown, MD, with two VN670 trucks. One was spec'd with the D13, 425-horsepower engine with the integrated I-Shift transmission and the integrated software (the new XE13 package). The other had a D13, 425-hp engine with a 10-speed manual transmission with Eco-Cruise and mass-based variable torque.
I opted for the first leg in the manual transmission truck, listening to the engine sounds and checking out the scenery. Comfortable, workmanlike, it was a good general-purpose fleet truck that moved smoothly through its paces. Quiet and responsive on fairly flat terrain down Interstate 81. We got down the road around 40 miles and swapped trucks.
What a difference technology makes. I stepped into the updated, upgraded VN670 and felt the changes immediately; starting with the I-Shift technology. Why would you want to think about grabbing gears when the transmission is smarter than your foot?
Uphill or down, traffic or none, it takes a seasoned driver and allows him or her to focus on everything other than the next shift point. The interior was quieter and more luxurious. As an owner-operator, I'd like this truck.
The visibility was unobstructed; side mirrors were mounted so that I only had to turn my eyes, not my head. Fairings have been redesigned to reduce air drag and the bug deflector has been moved to the middle of the hood.
We made our way down the road – narrow shoulders, a heavy truck traffic lane, a busy day. I tend to leave cruise control off when I'm on unfamiliar road, especially when it's rolling terrain and I don't know what to expect around the next curve. But in order to let the truck do its job, I had to do mine and trust the equipment.
We climbed a grade and I watched the rpms slowly drop. My fingers itched to downshift. I controlled the impulse and listened to the motor. No lugging or chugging; it just hummed along. The shifts were seamless.
The engine brake was so quiet on the downhill side I thought it hadn't engaged so I stepped on the brakes and disengaged the engine retarder. I was wrong. Trust the equipment. It's working.
From Hagerstown to Greensboro, NC, is about 325 miles. We swapped back and forth a couple of times during our six-hour journey to check out the varying terrains and road conditions and how the different trucks responded.
The sprinkles turned to rain, and the terrain changed from fairly flat to rolling to hilly. The scenery was spectacular; the beginnings of fall colors just dusting the leaves.
Ed Saxman and I were so busy talking about the changes in technology that I blew right past our exit. Oh well, a few more miles down the road and I turned around and came back.
Whether I drove or sat in the jump seat, with the XE13 package, I found myself watching the tach, seeing how low the engine would go before shifting – or how high.
I tried to drive for fuel economy, because even pulling stout grades I never had to think about what gear I should be in. According to the numbers provided by Volvo, at 65 mpg, the XE13 package runs at 1,156 rpm, the 10-speed at 1,404 rpm. The difference in fuel economy? If you were getting 7 mpg, with the XE package, a 0.2 mpg improvement is a realistic possibility.
That's fuel in the tank and money in your pocket – if you can trust the equipment and keep your foot out of your own way.
So what's the cost to the buyer? It's a programming option. So if the truck is spec'd for performance, not very much. The tuning software will be available in early December 2011.
I'd climb behind the wheel of this truck again. And next time I won't try to outsmart it (yeah, right).LL