WARRENVILLE, Ill. — You may want to add the term “fluid economy” to your truck vocabulary. It’s a term you’ll likely hear frequently from Navistar International as the company continues to forge its own path towards EPA2010 emissions compliance while avoiding SCR.
When measuring the costs of operating EPA2010-compliant trucks and engines, Navistar officials are urging customers to consider the overall consumption of both diesel and diesel exhaust fluid (DEF), a key ingredient required by engines using selective catalytic reduction (SCR). Doing so make its Advanced EGR solution look much more attractive, according to independent third-party test results released by Navistar today.
The results show that when taking the consumption of DEF into account, the truck maker’s rivals using SCR actually consume more fluid than the International ProStar+ with MaxxForce 13 engine.
The tests, conducted on public highways by Transportation Research Center following the TMC Type IV protocol, found the International ProStar+ with MaxxForce 13 consumed nearly 1% less fluid (diesel and DEF) than the Freightliner Cascadia with Detroit Diesel DD15 and nearly 2.5% less fluid than the Kenworth T660 with 15-litre Cummins ISX.
When asked why the company compared its own 13-litre engine to its competitors’ 15-litre offerings, Navistar’s senior vice-president of North American sales operations Jim Hebe said they chose the most fuel-efficient spec’ offered by their rivals.
“They are the engines they told us were the most fuel efficient they had in their lineup,” Hebe said. “That’s what they’re telling their customers as well.”
Navistar officials also said 13-litre offerings weren’t yet available from Cummins or Detroit Diesel for testing.
When looking at diesel consumption alone, Navistar says its truck and engine combo was within about 1% of its competitors. The results, Hebe said, exceeded the company’s own expectations. Hebe said the company internally had decided it could make a strong case for its Advanced EGR solution if it could get to within 2% of the fuel economy achieved by its SCR rivals.
“The closer we got, the closer we came to realizing not only could we provide parity, we could beat their claims as well,” Hebe said.
Navistar, of course, is the only Class 8 truck manufacturer in North America to tackle EPA2010 emissions standards without exhaust aftertreatment. Instead, International trucks will use increased levels of exhaust gas recirculation (EGR) combined with an enhanced fuel system and electronics to meet EPA2010 requirements. All other manufacturers, meanwhile, will use SCR, which requires the addition of diesel exhaust fluid yet allows the engine to operate more efficiently because NOx is not limited in-cylinder. At times, the debate over which solution works best has turned hostile.
“We’ve sat back the last couple of years and we’ve been shot at from about every direction you could be shot at with regards to our strategy for meeting 2010 emissions,” Hebe said. “We’ve seen competitors walk in and show presentations to our customers that say they’re 9% better (in terms of fuel economy) than we are. That clearly wasn’t based on fact. One of the biggest disservices we’ve seen some competitors do to the industry, is they only talk about the one fluid, they only talk about fuel and forget there’s this thing required in their system called diesel exhaust fluid or urea.”
Indeed, fuel economy has become one of the strongest selling points for engine manufacturers using SCR. Generally, they claim a 5% improvement over EPA07 equivalent offerings.
Navistar, it should be noted, has been redeeming emissions credits as it continues to wind its way down to the EPA2010 standard of 0.2 grams/hp-hr of NOx. Yet the company says it will not require liquid urea-based SCR at any time and reiterated it has a 15-litre MaxxForce on schedule to be launched in January 2011.
The TMC Type IV testing protocol requires similarly-spec’d trucks to be operated over the same route. In this case, a 444-mile route in Indiana was chosen. Drivers and trailers were swapped at the midway point and the consumption of both fuel and DEF was measured carefully. Navistar officials also said their ProStar+ with MaxxForce 13 is as much as 1,300 lbs lighter than competitive offerings with 15-litre engines using SCR.
Hebe said the test results were made sweeter by the fact the tests were conducted over long-haul, on-highway duty cycles, where SCR is said to be at its greatest advantage.
“The sweet spot for SCR was long-haul, on-highway and we beat them there,” he said.
Navistar officials said further tests will be conducted, including direct comparisons to competitive 13-litre engines which it has now obtained.
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