WHAT’S WASTE-HEAT RECOVERY?

October 20, 2010 Vol. 6, No. 21

Ever heard of exhaust waste heat recovery? You will soon, because every North American truck engine maker is pursuing it as a way to meet the coming U.S. fuel economy mandate. When President Obama signed a memo this past May telling the EPA to come up with standards on greenhouse gas emissions and fuel economy for light-, medium- and heavy-duty trucks, starting with the 2014 model year, the engineers saw that capturing exhaust heat and converting it into mechanical energy would eventually have to be part of the fix on the heavy side. I’m sure the requisite technology had been explored long before — it’s just that obvious — but now we’re going to need it.

The notice of proposed rulemaking will likely be published next Monday, according to Cummins chief technical officer Steve Charlton. He was one of five speakers at an excellent panel session held during this week’s American Trucking Associations management conference in Phoenix, Arizona. Coulda used some waste heat recovery down there, I can tell you, though this particular session — under the accurate theme, ‘Washington is Reinventing the Truck’ — was first rate. It featured speakers from the four truck OEMs that also make engines, as well as Charlton.

Anyway, the details of what’s coming are unclear, but what’s likely is the demand for a 3% fuel-economy improvement for heavy trucks by 2014, and another 2% by 2017, using 2010 as the base line. Other demands will target 2020 but there’s no indication as to what they’ll amount to. Light and medium-duty trucks are going to be part of the proposal too, but I’ll just talk about heavies here.

The panelists seem to agree that finding 3% for 2014 will not stretch the technology, nor your wallet. Jack Allen, president of Navistar’s North American Truck Group, called the requisite changes "evolutionary". In some cases, he said, off-the-shelf technologies will be used, along with others already almost fully developed. "Basically we’ll have what you now see in SmartWay trucks," he said.

"I see enhancements of today’s technologies through the 2015 time frame," added Paccar vice president Craig Brewster.

Brewster also made a point that I’ve made here before    , namely that with the breadth of vehicle diversity we presently have, there’s potential trouble in making the rules fit all trucks.

"I believe the biggest risk is that these regulations will render some trucks less efficient."

Charlton said 2014 engines will employ optimized SCR. ‘We think we can avoid any major additional cost," he added.

For the 2015-16 time frame, he said one key technology focus will be on reduced friction, but by 2017 engine-makers will likely have to use exhaust waste heat recovery (WHR) to meet the EPA’s goals. And while we won’t see any of this causing a weight gain on trucks before then, WHR will indeed make trucks heavier by an unspecified amount.

WHR is a simple concept using fundamental principles but it will mean "a complex package," according to panelist Tony Greszler, vice president government and industry relations for Volvo Powertrain. It involves multiple heat exchangers. He added that the heavier the load, the better it works.

Greszler was critical of Washington for its poor understanding of trucking’s realities.

"Washington economics are not quite the same as your own," he told his ATA audience. "Historically [real] costs have been under-estimated and benefits over-estimated."

For example, the EPA’s thinking assumes a 10-year truck life while fleet owners think in terms of four-year trade cycles and two-year paybacks. The two camps put wildly different values on fuel economy as well, he said, explaining that Washington over-values it by about 10 times compared to the fleet view.

Martin Daum, president and CEO of Daimler Trucks North America, had similar criticisms. Like Greszler, he questioned the EPA’s plan to separate the engine and the truck in the proposed rules.

"You can’t just optimize an engine to optimize freight efficiency," he said.

That notion of overall freight efficiency was his key point in an entertaining presentation.

"We have to talk about transport efficiency," he said. "Two 30-ton trucks use far more fuel than one 60-ton truck… Transport efficiency is a very, very important term that we have to get into the minds of politicians."

Later, in the Q & A period, he repeated that point and wrapped things up by saying, "A fully loaded Freightliner Cascadia with a DD15 engine is about 10 times more efficient than a Toyota Prius." The crowd laughed hard.

I’ll pursue WHR technology and report back ASAP. For now I’m going to take us back to the IAA show in Germany as there was a lot of material I haven’t had space to cover before now.

MAN SHOWED A CONCEPT TRUCK at IAA, namely its Concept S truck with an extremely low drag coefficient of around 0.3. MAN says that, with an appropriately slippery trailer, it uses up to 25% less fuel than a comparable, conventional 40-tonne tractor and semi-trailer while providing the same load capacity.