The Fleet Business Authority
Issue link: http://heavydutytrucking.epubxp.com/i/236631
transparent to the customer," says Roy Horton, Mack Truck's powertrain product marketing manager. "Basically, an OEM would use the EPA-provided Greenhouse Emissions Model to calculate the carbon dioxide emissions in grams/ton-mile for a specific vehicle." Inputs to this model include the vehicle aerodynamic value, steer-tire rolling resistance, drive-tire rolling resistance, vehicle speed limiters, idle reduction and weight reduction values. This output is then compared against the EPA-defined industry standard, he explained. "Greater or lesser GEM values for a specific truck model, multiplied by the yearly sales volume and useful life value, create the debits or credits." The powertrain OEMs say they're achieving the goals. Volvo Trucks, for instance, announced that its 2014 diesels would be 0.5% to 2% more fuel efficient, offering a significant return on investment for fleets and owner-operators. "Volvo trucks equipped with 2014 engine technology will deliver substantial fuel efficiency benefits, while also providing the power and performance customers expect from a Volvo powertrain," says Göran Nyberg, president of Volvo Trucks North American Sales & Marketing. Advancements over previous Volvo engine models include smoother surfaces on pistons and liners for lower friction; seven-hole injectors that better atomize and distribute fuel within cylinders; a crankcase ventilation system that filters more oil from blowby gases before they leave the engine while lowering backpressure for better performance; and a clutched air compressor that com- www.truckinginfo.com pletely disengages from the engine to cut parasitic loads. Mack Truck, which obtains its engines from Volvo Powertrain, lists similar improvements. "Downspeeding" is being emphasized by Volvo and Mack, which have introduced packages using low-rpm cruising speeds with automated mechanical transmissions. Volvo calls it XE, for exceptional efficiency, and Mack names it Super Econodyne. Fuel efficiency improves by about 1.5% for every 100 rpm of downspeeding, so customers spec'ing the XE package can expect up to a 3% improvement compared to an overdrive manual transmission in a similar operation, Volvo says. and Mack, take gearbox operation out of driver's hands: the CumminsEaton Smart Advantage powertrain, which claims to save 3% to 6%; an exclusive-to-International 16-speed direct-drive UltraShift Plus LSE, for a 6% fuel savings; and Allison's TC10 10-speed torque-converter automatic, which Allison says averages 5% better economy over manual transmissions. "For fuel efficiency, improvement efforts are always ongoing – they aren't 'light-switch' events," says spokesperson Elissa Maurer. "One of the key areas of focus for this phase of GHG was the transition to SCR emissions technology. Our heavy-duty SCR product transition was completed in October and is moving forward, ontrolling greenhouse gases could help slow down global warming with its rising seas and weather extremes. C Freightliner has begun pushing its proprietary 12-speed Detroit DT12 automated transmission to better control gear shifting and engine speed. When used in conjunction with the Detroit brand engines and axles, it can offer even further fuel economy improvements. Freightliner also offers Eaton's UltraShift Plus AMTs. Kenworth and Peterbilt have been working with Eaton to improve operation of the UltraShifts, and now upshifts occur sooner to avoid high engine revs. The Paccar brands also have tweaked their Paccar MX-13 diesel to use less fuel. Navistar International also is using downspeeding, and to achieve it offers several products that, like Volvo and we'll look to reduce some of the added componentry that was needed for EGR. We expect that process will reduce some weight and also lead to further fuel economy improvements." SCR – selective catalytic reduction – uses urea injection to break down nitrogen oxide in the exhaust. This takes strain off the engine and allows it to breathe easier, cutting fuel consumption. Competitors have been reporting fuel-economy gains since they began using SCR in 2010, but Navistar switched over last year. Aerodynamics and more All OEMs say they have further polished their current models' aerodynamic performance. For example, JANUARY 2014 • HDT 33