With the tail end of the greenhouse gas (GHG) Phase 1 requirements now surfacing in engine makers’ more fuel-efficient 2017 lineups, a GHG Phase 2 rule is knock, knock, knocking on trucking’s door. How will the industry actually get there? How will manufacturers reach these fuel efficiency gains? Will they be measured as an average of all of an OEM’s products or carved out in segments?

The first and most basic answer to “getting there,” in many ways, is to reduce friction while maintaining performance. Reduce drag on the truck and trailer bodies and improve aerodynamics; use various methods to reduce friction in the engine itself; literally reduce resistance where the rubber hits the road; and any other opportunities you find as you claw your way to moving a hauling machine of up to 80,000 lbs. down the road at higher mpg.

By 2027, in what the involved federal agencies call “an ambitious, yet achievable program” in their proposal, combo tractors designed to pull trailers are likely to have a 24% fuel efficiency gain to meet and trailers another 8-12%, while separate standards for engines will likely call for 4% higher fuel efficiency compared with 2017 models. “For heavy trucks in 2027, let’s call it 9 mpg,” says Michael Roeth, executive director of the North American Council for Freight Efficiency (NACFE), simplifying and summing up the target goal from that angle.

There’s an app for that

To a point, the U.S. Environmental Protection Agency (EPA) and National Highway Traffic Safety Administration (NHTSA) have spelled out the technologies that come under GHG Phase 2 through their Greenhouse Gas Emissions Model (GEM) compliance simulation application for manufacturers. Companies input specs, usage parameters and particular fuel economy technologies for their tractors, engines or trailers and are essentially given a unit’s fuel efficiency figures used to monitor if the OEMs’ products are compliant with GHG targets.

“Each truck, for example, will get a number. As greenhouse gas stringency comes down from the federal government, manufacturers will run a number on every truck they build,” Roeth tells Fleet Owner. “You take all the trucks Kenworth builds, all the trucks that International builds and so on, and they’ll need a certain average to be compliant.

“There are many technologies to choose from,” he continues. “There’s aerodynamics on the tractor and trailer, lower rolling resistance tires, engine changes, gear ratios for downspeeding, automated manual transmissions, idle-reduction solutions—there’s a whole bunch of things the EPA has defined as technologies in the GEM program.”

According to EPA and NHTSA, the GEM program “is capable of recognizing most technologies that could be evaluated in both engine and chassis dynamometers and is [now] better able to reflect changes in technologies for compliance purposes.”

In GEM, some technology options for tractors are vehicle speed limiters, weight reduction, low-friction axle lubricants, predictive cruise control, high-efficiency A/C compressors, electric engine coolant and power steering pumps, automated tire inflation systems, and extended idle reduction. Vocational vehicles can add power take-off options, while trailers can have things like aerodynamic drag, weight reductions, and tire pressure inflation systems.

OEMs are innovating on their own, of course, as the GEM program envisions and is designed to accommodate. One driver of fuel economy innovation has been the SuperTruck public-private partnership, a project that’s now generated a sequel where the U.S. Dept. of Energy puts up grant funds to share costs for projects to reach large mpg improvement goals.

Volvo Trucks, for one, says its team developed some of the company’s latest engine improvements working in the SuperTruck program. Some enhancements that came from it are going into 2017 D11 and D13 engines particularly.

Those include Volvo’s “wave piston” technology and turbo compounding, and there’s also a new fuel rail, higher engine compression helping boost horsepower and torque, and other enhancements in terms of powertrain like improvements for I-Shift transmissions at both low and high speed. But the wave piston, as Volvo calls it, is one of the more standout technologies you’ll find claiming to unlock more fuel efficiency and making for a cleaner-burning engine.

In that patented design, explains John Moore, powertrain product manager, Volvo reshaped the top of the piston and therefore the combustion chamber. Imagine carving out six U’s end-to-end around the top of a piston and connecting them in a circle. You’ll have the high points where each U begins, the low points at the bottom of the curve, and the high points coming back up out of the U.

So think of those points as peaks and troughs of waves, and voila: “wave pistons.” Add to that a six-directional fuel injector nozzle that squirts fuel right at each wave trough or divot in the top of the piston.

“You’ve got six holes on the injectors—one hole for each of those tabs on the piston—that spray fuel right at those tabs. The fuel actually will hit them, turn around and come back to the center of the cylinder,” Moore explains. “We call that ‘flame propagation toward the center,’ and it fosters a more complete, cleaner burn. 

“With the conventional pistons we were using before, you would spray fuel from the injector into the cylinder; it would come straight down, hit the crown of the piston dome on top, then scatter and go to the piston walls,” he elaborates. “And once it ignited, you might have fuel on the cylinder walls that turned to soot.

“The wave pistons eliminate those ‘wet spots,’” Moore explains, “and that’s where we’re picking up a cleaner burn and increased fuel efficiency as well as 90% less soot output on the cylinder unit.”

Far from the majority yet

That’s just one closer look at how OEMs are finding myriad ways to boost mpg in trucks, engines and trailers, and you can expect to hear more—possibly from what’s been learned with concept vehicles—as 2017 engines start rolling off production lines.

“But have you ever seen one of those ‘SuperTrucks’?” asks Charlie Fetz, vice president of design and development at Great Dane Trailers. “How many of those things do you see running around on the road?”

It’s true, Fetz points out, that there are fleets reaching efficiency levels with their trailers today at the 2027 levels envisioned in GHG Phase 2. “There are fleets running lots of aero, running wide-base single tires, probably with weight savings and so forth,” he notes. “But they’re long-haul guys. Have you ever seen a tractor-trailer pulled up at a restaurant?

“The guy is there in the lot with his ramps coming out. He’s wheeling boxes of stuff into the restaurant with a hand truck,” Fetz continues. “He’s got ramps stored under his trailer, beverage canister racks and pallet racks, and he’s got a roll-up door at the rear.

“That trailer doesn’t have a lot of aero opportunities. He’s running short-haul. When he gets into the city, he’s going around doing multiple stops, creeping around restaurant to restaurant, probably averaging 18, 20 mph,” he explains. Thus, Fetz makes the point that trailers come in different shapes and sizes on trucks doing very different jobs, so getting to GHG Phase 2 fuel efficiency targets is far from cut-and-dried.

“Although there are a number of devices on the market today, trailer side skirts and low rolling resistance tires have proven to be most effective; as a result, they are the most adopted by U.S. fleets,” says Brian Bauman, vice president and general manager of Wabash Composites. “Generally, the aerodynamic devices that are being adopted most are those that are proving to be the most durable and least intrusive to the daily operations of the fleet.”

Stand-alone devices available for trailers can yield between about 1% to 9% fuel economy improvement in highway use, Bauman contends, and Wabash has device combinations available that can produce upwards of 10% fuel savings.

And the nature of trailers themselves is complicated, Fetz contends. “You don’t go to a Ford dealership and say, ‘I really like that Taurus, but can you make it two feet longer and add another axle?’” he points out. “But that kind of thing is commonplace with trailers.”

Before the final rule comes out, Fetz notes, trailer, truck and engine OEMs have stayed in touch with EPA and NHTSA to provide input and feedback. He notes that Great Dane has done that both on a one-on-one basis as well as with industry groups. “The EPA will be quick to tell you they want to have an effective rule that’s enforceable,” he says.

“We also try to help fleets understand what’s in this rule and what they may have to do,” he says, such as add low rolling resistance tires or a tire inflation system to their trailers. “The burden of compliance falls on manufacturers, but there are implications about the buyer having to maintain technologies on the equipment,” he notes. 

Squishy balloon

If you think OEMs getting to fuel efficiency targets in GHG Phase 2 is a given, you may have missed a few things, cautions Glen Kedzie, energy and environmental counsel for the American Trucking Assns. (ATA) and staff liaison for the organization’s Fuel Efficiency Working Group. It’s one of the channels by which federal agencies are interfacing with the trucking industry, as Fetz describes.

ATA has raised a few concerns: the diversity of trucking, volatility in the cost of fuel, and the difficulty of being accurate with estimates EPA and NHTSA make in the GHG Phase 2 rule for things like a fleet’s return on investment after purchasing fuel-saving technologies. But there’s another big variable out there, Kedzie says, and that is a potential reduction in NOx emissions that could hit “smack dab in the middle of implementation of the Phase 2 rule.”

He contends California is considering bringing a lower NOx emissions standard to the market soon. “Typically, when you’re trying to address NOx emissions, it’s going to have an inverse impact on fuel economy,” Kedzie tells Fleet Owner. “It’s kind of an unintended consequence we’ve seen.

“It’s like an ecosystem: All these things are interrelated. I call it the ‘squishy balloon concept’: If you squeeze one of those long balloons on  one end, the air goes to the other end,” he continues. “You’re still going to have the same amount of air in that balloon; it just depends on where the squeeze is happening and what the reaction is in other parts of it—unless it pops.”

In the final rule, OEMs will likely be able to carry over fuel efficiency deficits, should they have them, for up to three years. But on the other hand, if OEMs overachieve the rule’s targets, any overage can likely be put in their ‘credit piggy bank’ to balance the books if need be,” Kedzie says, and credits can be carried forward up to five years. So he does have some advice for OEMs: Get started strong and quickly with fuel efficiency technology, and build up extra credits to carry forward in case later targets are difficult to hit.

“Sell things that are super-efficient, and anything that’s over what the target is, bank those credits. It’s kind of a rainy day fund. It’s hard for OEMs to predict the future, but if they fall short, at least they can tap into their credit piggy bank.”

In a final point, NACFE’s Roeth thinks the medium- and heavy-duty trucking industries should take a deep breath.  “There are clearly challenges in getting to these levels of fuel efficiency and greenhouse gas reductions, but it’s possible,” he says. “We’ve got some time. We need the technologies to improve; we need their costs to come down; and we need their consequences to be reduced. But I believe it can be done.”