Hoping for new technologies that could double the amount of freight a heavy-duty truck can haul on a gallon of fuel, the U.S. Department of Energy is launching a new phase of its recently completed SuperTruck program.
Dubbed SuperTruck II, the five-year, $160-million program will see the same four teams of truck, engine and trailer builders from SuperTruck 1 attempt to move far beyond the successes they’ve already racked up. The teams spent $258 million – a combination of federal funding and their own money – on the first program.
After setting “big, hairy goals” for freight-hauling and engine efficiency in SuperTruck I, which each team met or exceeded, the new program aims to push truck, tractor and trailer manufacturers to even loftier heights, said Michael Berube, head of the Energy Department’s vehicle technology office.
“We want them to achieve those new goals using technologies with realistic potential” for cost-effective use in the real world, Berube said.
The federal government will provide $80 million of the SuperTruck II funding, subject to annual congressional approval. Each team will match taxpayer dollars with private funds.
The program represents a successful public-private partnership that “has allowed industry as a whole to take on more risk and invest at a higher level much earlier in the technology development process than would otherwise be possible,” said Paul Miller, director of research and technology collaborations at Cummins, Inc.
“This program was rooted in the idea that we were not just going to develop a showpiece, but to come up with things that could be put into commercial use,” said Ken Damon, technical project leader for Peterbilt.
The four teams — which include tire manufactures, trailer builders, fuel system designers and other specialists — are headed by Cummins Inc. and Peterbilt Motors Co.; Daimler Trucks North America; Navistar International Corp.; and Volvo Group.
SuperTruck II is looking for a 100 percent increase in freight-hauling efficiency and a new engine-efficiency standard of 55 percent, a 31 percent increase, from a 2009 baseline measurement.
Freight efficiency is the amount of freight carried and miles traveled for each gallon of fuel consumed. Engine efficiency, known as brake thermal efficiency, or BTE, is the ratio of fuel energy converted to power output at the engine’s crankshaft. The industry average BTE for a 2009 Class 8 engine was 42 percent; SuperTruck 1’s goal was 50 percent.
Each team will measure improvement from its truck-maker member’s best-performing 2009 Class 8 tractor and engine. For competitive reasons, the teams are not required to release their base trucks’ performance numbers.
Each of the teams met or exceeded both goals in SuperTruck 1, and in doing so their prototype truck-trailer combos also demonstrated improvements that boosted fuel efficiency by 71 percent to 104 percent. The average fuel efficiency for the base tractors was 6.2 mpg.
Trucking’s Oversized Impact
The rationale for SuperTruck and its federal backing is found in the outsized contribution heavy-duty trucks make to both the U.S. economy and the nation’s air-quality problems.
The Energy Department says that on-highway heavy trucks haul 70 percent or more of all freight tonnage moved in the U.S., about 80 percent of all goods, and gulp down almost 20 percent of the nation’s petroleum-based transportation fuel. They spew about the same amount of greenhouse gas emissions.
Making more efficient Class 8 trucks helps slash the country’s petroleum thirst, cleans the air and puts more money into the pockets of truck operators, goods producers, wholesalers, retailers and consumers by reducing shipping costs.
Real World Successes
All of the prototypes developed for SuperTruck I made heavy use of streamlining features – aerodynamics – including adding turbulence-reducing devices such as wheel and trailer side skirts or removing external mirrors in favor of flush-mounted cameras with interior display screens.
But all went beyond that with features such as predictive cruise control to automatically match shifting and speed patterns to terrain, special low-resistance tires, lightweight frame and suspension components, electrified accessories such as cabin heat and air conditioning to reduce idling time, engine and transmission controllers matched and mated for efficiency and even new piston and turbocharger designs.
Many of these features are starting to show up in the latest generation of commercial trucks,
including Class 8 tractor aerodynamics packages from Denton, Texas-based Peterbilt, Cummins newly released X15 engine series and a new diesel engine piston design and turbocharging system from Volvo Trucks North America. Navistar has a predictive cruise control system in mass production and in April will be releasing a redesigned 13-liter N13 engine that uses several SuperTruck-developed improvements, including new control logic and a high-efficiency combustion system.
Rule Changes Needed
But some of the technologies used in Phase 1 of the program would require federal or state rule changes for commercial application. External mirrors, for example, are required under federal safety regulations, and switching to camera-based side- and rear-view systems would require a rewriting of the governing codes, Berube said.
The location of marker lights above the rear doors of freight trailers also is regulated by safety codes that likely would have to be altered if trailer tail extensions – or fairings, which reduce efficiency-robbing air turbulence — are widely adopted. The Volvo team found that the fairings, mounted flush with the trailer roof, can provide as much as a 1.4 percent boost in fuel efficiency. Unfortunately, when mounted that way they cover the marker lights, said Volvo project director Pascal Amar.
By team, here are the SuperTruck 1 accomplishments and the SuperTruck II aspirations beyond the program’s stated goals:
The teaming of Cummins and Paccar’s Peterbilt truck unit resulted in a streamlined package that boosted total freight efficiency by 86 percent above the base 2009 Peterbilt truck’s capacity, with a 75 percent improvement in fuel efficiency to 10.7 mpg, and engine brake thermal efficiency of 50 percent.
For SuperTruck II, the team is aiming for rapid market introduction of technologies developed to meet the program’s new goals.
“We’ve been living in a GHG [greenhouse gas] world since 2014,” Peterbilt’s Damon told Trucks.com. “We have obligations to our customers and to the EPA” to improve truck efficiency “and we have to continue to develop technology as quickly as possible.”
To that end, the Cummins-Peterbilt team is working closely with Walmart to better understand how a major fleet customer views the newly developed truck technologies from a cost-effectiveness perspective, said Mike Ruth, head of the Cummins' SuperTruck program
Cummins will be introducing several SuperTruck 1 improvements on its 2017 engines, mainly centered on friction reduction, air and combustion system improvements, said Jon Dickson, system performance and vehicle integration lead for the program.
In SuperTruck II, the emphasis will be on engine light-weighting and further reductions in engine friction and parasitic power drain from the cooling and lubricating systems.
The Cummins-Peterbilt team also will be working with its partners on low rolling resistance tire development and trailer improvements, Ruth said.
Daimler Trucks North America:
The Portland, Ore., builder of Freightliner trucks and Detroit Diesel engines headed a team whose prototype truck achieved a 115 percent increase in freight efficiency, doubled fuel efficiency to 12.2 mpg and hit the program’s engine efficiency goal of 50 percent BTE.
For SuperTruck II, the company sees “more opportunity to make gains in efficiency to improve both the environment and the profitability of our customers,” project leader Derek Rotz said in a statement.
The Daimler team’s SuperTruck 1 prototype included a special lightweight wheel and hub as well as specially formulated low rolling resistance tires form Michelin, a lightweight frame and suspension that slashed 700 pounds from the tractor, and a downsized hybridized powertrain featuring a 10.7-liter engine boosted with an electric motor and a waste heat recovery system.
SuperTruck “let us push further than we had been planning with our advanced development,” said Charles Chilton, engineering director for heavy-duty trucks at the Lisle, Ill.-based truck and engine maker.
In the first phase, the Navistar team’s prototype truck demonstrated a 104 percent hike in freight efficiency, a 50.3 percent BTE and program-leading fuel economy of 13 mpg.
“We don’t expect to commercialize 100 percent of the technologies” Navistar will develop to meet the program goals, “but a lot will make it to market,” Chilton said.
The Volvo team lead by Volvo Trucks North America turned in an 88 percent freight efficiency improvement with its SuperTruck 1 entry, along with a 71 percent increase in fuel efficiency – to 12 mpg from a class-leading 7 mpg in its 2009 base truck – and an engine efficiency ratio of 50 percent.
The Greensboro, N.C., truck maker credits development of a new piston design and an enhanced turbocharging system for much of the improved fuel efficiency and has already begun using the piston and turbocharging system in engines being updated for the 2017 model year, said Amar, a Volvo Group senior project manager.
In addition to engine improvements, a number of aerodynamics advancements developed by the team for use on Volvo’s SuperTruck prototype were put into mass production on Volvo’s 2016 model year Class 8 on-road tractors in North America, he said.
The goal in SuperTruck II is to “bring as much improvement as possible as quickly as possible to our customers,” Amar said. “Compared to where we were five years ago, we will be able to hit the ground running in Phase 2.”
Trailers Take the Lead
SuperTruck participants were unanimous in praising the program as one that enabled them to push technology development further and faster than they’d thought possible.
One key benefit cited was the opportunity, in Peterbilt project leader Damon’s words, “to form a team that was able to look at things in their entirety, from tractor to powertrain to trailer.”
The Volvo team discovered that aerodynamic treatments developed for tractors pulling older, non-streamlined trailers don’t work with newer, more streamlined trailers. That means when streamlined trucks and trailers are teamed up, their individual improvements often increase turbulence rather than reduce it, Amar said.
As a result, Volvo redesigned its Class 8 highway truck bumpers “to improve interaction with aerodynamically designed trailers,” and that helped deliver the team’s big fuel-efficiency gain, he said.
Another improvement involving the interaction of tractor and trailer came from the Navistar team, which discovered that closing up most of the open space between the rear of the tractor and the front of the trailer, using lightweight fairings and a shorter coupler, delivered a substantial reduction in efficiency-draining air turbulence.
“SuperTruck II has set goals beyond where the companies think they can be,” Berube said. “By providing some federal money to help them, the program will allow them to try higher-risk technologies than they might on their own.”
Most of the teams, for instance, have indicated that they will be looking at various forms of hybrid diesel-electric powertrains in the second phase, he said.
“Think of the benefit to the industry and to the country if they can meet that goal of doubling freight efficiency. There are 2.5 million Class 8 trucks out there, each traveling an average of 66,000 miles a year. Doubling their efficiency could reduce petroleum consumption by 300 million barrels a year,” he said.
At today’s fuel costs, the DOE figures, that would save operators up to $20,000 per truck per year.