Volvo Trucks is furthering its North American fuel efficiency leadership with the addition of two XE exceptional efficiency drivetrain packages featuring the 16-liter Volvo D16 engine. The first, a heavy-spec XE16 package rated for combination weights up to 143,000 pounds, was designed specifically for the North American heavy long combination vehicle (LCV) market. The second XE16 package combines exceptional fuel efficiency with outstanding performance for five-axle tractor-semitrailer combinations up to 80,000 pounds.
Volvo Trucks Extends Award-Winning 'XE' Fuel Efficiency Package to 16-liter Engine
"XE16 directly addresses the needs of two important market segments that historically have had very few fuel-efficient powertrain options," said Ed Saxman, Volvo Trucks drivetrain product manager. "The beauty of Volvo's XE powertrain is that it delivers the full power and low-end torque needed for higher weight applications while saving fuel by running at a lower rpm."
The XE16 packages "downspeed" the engine at cruising speeds by 200 rpm or more than traditional specs. Each package utilizes a new D16 engine rating of 500 horsepower and 2,050 lb-ft. of torque, Volvo I-Shift automated mechanical transmission, specialized axle ratios, specific tire sizes and proprietary software that facilitates seamless communication among Volvo's integrated powertrain components. The XE16 provides the full 2,050 lb-ft. of torque while running as low as 1,000 rpm to improve low-rpm drivability. Key enablers of XE16's low engine speed technology include the exceptionally powerful Volvo Engine Brake, as well as massive connecting rods with large bearing surface areas that help alleviate bearing stress.
"Both XE16 packages provide unheralded fuel efficiency for customers requiring high horsepower and torque and the heavy-spec XE16 package is the first integrated fuel efficiency powertrain designed exclusively for the over-the-highway North American LCV market," Saxman said.
XE16 package for vehicle combinations up to 143,000 pounds
Developed for gross combination weights up to 143,000 pounds, the heavier-spec XE16 package utilizes heavy-duty suspensions and rear axles with a 3.21 ratio instead of the 3.73 rear axle often specified on North American LCVs. The XE16 package reduces cruising rpm from 1,425 to 1,225 at 62 mph (100 kph), yielding about a 3 percent fuel efficiency improvement.
XE16 package for vehicle combinations to 80,000 pounds
The second XE16 rating addresses 80,000 pound tractor and semi-trailer combinations that are specified with a focus on both fuel efficiency and high performance. The engine, in combination with a 2.64 rear axle ratio and overdrive I-Shift transmission, will operate within its sweet spot throughout the vehicle speed range to improve fuel efficiency for this class of vehicle.
Volvo first introduced its "downspeeding" concept in September 2011 with the XE13 powertrain package, which utilizes Volvo's 13-liter D13 engine. Available on all VN highway tractors, the XE13 powertrain package offers up to 455 horsepower and 1,750 lb-ft. torque at 1,050 rpm 200 rpm or lower than traditional specs.
The Truck Writers of North America (TWNA) awarded Volvo's XE13 powertrain package the 21st annual TWNA Technical Achievement Award. XE13 also received a 2012 Top 20 product award from Heavy Duty Trucking magazine.
DorogaRoad took the opportunity to talk at TruckWorld 2012 to Ed Saxman, Volvo Trucks drivetrain product manager and Brandon Borgna, Volvo Trucks media relations and communiucations manager.
Ed Saxman, Volvo Trucks drivetrain product manager and Brandon Borgna, Volvo Trucks media relations and communiucations manager
Ed Saxman: We were very happy to receive that award on behalf of the company and it was interesting and unexpected. First XE13 was introduced to our dealers in September of 2011. What we are doing is we are taking an existing engine, the existing transmission and rear axles and making a package. Not to take away from anything else, you can still buy whatever you want. But if you want to order this package, it would all come together .The package is made for very slow operational engines, it involves not just the rear axle ration and the tire size, but also some software that we included there to tune it. It requires the i-Shift transmission because this is pretty much a part of it.
In other words, we came up with a drive train and we are saying it works. A typical speed in the United States is 65 miles/hour, so an engine only runs 1150 RPM at 65 miles/hour. That is very slow, and that is what you have in top gear. What if you hit a hill? Yes, it can shift out, many of the newer cars are doing the same thing, or they are very tall in their gearing but they shift out and you don't even notice it, it's automatic, and the RPM just goes up a little bit. In our case you are shifting into a direct drive, and so you can run a direct drive all day long, literally. It will be a twelve-gear run from coast to coast; it's designed for North America interstate highway travel, not in the towns...
As it was mentioned above, we offer two packages of XE16 for vehicle combinations up to 143,000 pounds and for vehicle combinations up to 80,000 pounds. By using either one you gain about 3% fuel economy and you have been running the engine right in the middle of that sweet spot. Even if it downshifts and you block it down to where it wants to, downshift, it's all automatic, so you just let it shift on its own. When it comes in on the next tire or RPM you are still in the sweet spot, and it doesn't even feel fast, because that's what you are used to, it's a normal operating range, it's what you'd be doing if you didn't have an i-Shift.
This all started out to be "What could you do to make a special tractor designed to haul direct on an outbound load and then empty on the return load, and if it is empty then you could haul overdrive coming home." What we found out is that now we can haul overdrive on an outbound load even with these ridiculously low axles. And then I say "Well, we can keep it overdrive, what if we can also sell it to the guy who comes back with a load. It's not just the guy who hauls one way, it's everybody. So the load can be one that's diminishing and now the weight is getting lighter as you go, or empty return, or fully loaded either way, we don't care. But it's got to be more efficient, you'll have more of an effect the lighter you go, and that's because the fuel that's consumed just to make the engine go around at 1300 RPM, and that's a lot of fuel. It's more percentage of the total load if you are only hauling empty trailer, than it is if you are loaded, so you will see greater percentage gain in fuel economy if you are lightly loaded, because the engine is idling so to speak.
DorogaRoad: You mentioned the 3% fuel economy. Is it compared to a similar truck without the package?
Ed Saxman: Yes, everything is the same, same engine roughly, with an i-Shift transmission with 3.73. It's a downspeeding of the engine, and our quote was back in September, and we are still standing by it, for every 100 RPM that you downspeed the engine, you gain about 1.5% in efficiency. Overdrive to overdrive, we are slowing down 200 RPM so that works out to about 3% in efficiency. That turns out into about 2000 dollars per year for a truck such as XE13 which is lightly loaded with 7 miles/gallon. So for a heavier combination, depending on your aerodynamics and your trailer, this varies a lot, because a lot of them are flatbeds, what I call trailers with a lot of edges. You know what I mean that's not really aerodynamic. In those combinations fuel economy is penalized but still you see a huge improvement in economy because of the downspeeding of the engine.
DorogaRoad: It's pretty impressive 3%. What else is in store for the truckers from the Volvo R&D department? What can we expect next?
Ed Saxman: We don't usually talk that far ahead, but you are going to see continuing efforts to keep on polishing the edges on fuel economy, here and there. We already have an excellent position because we've been doing this for so many years, and we came out with the world's first aerodynamic tractor, with a full aerodynamic fairing in 1983. That was when I joined the company about 30 years ago. I can still remember when we came out with that and you could really feel the difference because compared to without roof fairing, it made a huge difference. And some people are only learning that today.
But if you do it, what's next? Well, the next one won't be as big but you have to keep on polishing it, and we are still working. The engine is the same way, and we think this is a pretty significant change; we have gone now as far as we can go now in running the engine slower. I am 64 years old, and I remember when I started, when you drove the truck at its highest RPM possible, and that's how you controlled speed, so everywhere you went it was 2100, maybe a little bit faster in RPM. Over the years it came down slower, slower and slower to 1375 at 65 miles/hour. And now we are saying 1150 at 65 miles/hour, and for a heavy truck 1300 at 62 miles/hour. So it's been a long way, but this the way to run the engine.
When you have an engine that's this healthy and strong, it feels good. There are several things that we call key enablers for this to happen. One is you have to have a transmission that thinks as closely to the engine as the Volvo i-Shifters to the Volvo engine. They actually have the same intelligence, I mean, they are designed by the same people. The transmission knows everything there is to know about the engine. And likewise, the engine knows everything about the transmission, and we actually enable the i-Shift transmission to have a lot of control in this software as well as some other things over the engine in ways that would be difficult to do if they were separate components. That's one. Then you need a really strong engine brake. Volvo has always had a powerful engine brake and slower RPM. So we have a healthy engine, right? If not the healthiest in the industry.
DorogaRoad: And what is coming next?
Ed Saxman: It's fuel efficiency. That's on the forefront of everyone's mind, we have been very focused on that through aerodynamics, efficient engines, and it's going to continue to be the focus, we want to be able to offer a very strong value to the consumers, allow them to consume less fuel...
DorogaRoad: I know you are also constantly working on improving the comfort for the driver
Ed Saxman: If you talk to someone who has driven an XE13, and ask them "How do you like this new engine?" Almost always, the first two words are "It's quiet", because it is, it's another gear slower, the engine is just idling over, and then "you know when I drive this truck I am so relaxed". Now I can just let the i-Shift handle the truck and I can sit back and I realize how I am staying with everybody, and still got 500 horsepower, and with the engine this quiet I don't get that agitated if someone cuts me off, I am more patient with other people.
Brandon Borgna: There are certain characteristics that people expect of Volvo, and when developing products we try to retain that it drives and feels like a Volvo.
Ed Saxman: Our core values are Quality, Environment and Safety. Environment includes the fuel efficiency, quality is doing things right, and safety is has always been important. So we spend a lot of time during our truck development to make it safe. And we do some things that other people don't do. We have airbags inside our trucks. For example, if there is a tremendous crash, often the engine is pushed inside the cabin, while on Volvo the engine goes down, breaks transmission apart from the engine, but it doesn't go into the cabin, so it protects the driver. And there are so many things that we do like that.
DorogaRoad: Thank you for your time gentlemen.