Cummins announces results of ATLAS 2.8-liter diesel engine program
27 March 2015
Cummins is showcasing the results of the Advanced Technology Light Automotive Systems (ATLAS) program with the US Department of Energy (DOE) at the Mid-America Trucking Show. The ATLAS program was initiated to develop a commercially viable diesel engine for the half-ton pickup truck market that is capable of meeting US EPA Tier 2 Bin 2 emission regulations and Corporate Average Fuel Economy (CAFE) and greenhouse gas (GHG) requirements out to the year 2025.
The demonstration vehicle, provided by Nissan North America, is a 2010 Nissan Titan® originally equipped with a gasoline V8 engine. In addition to meeting fuel-economy and emissions requirements, the new engine needed to accomplish the same work as the large gas V8, so maintaining a torque output of 385 lb-ft (522 Nm) was necessary. The Cummins team chose a 4-cylinder ISF2.8 base engine to begin research.
The critical technologies for meeting the program objectives included advanced emission control, thermal management and powertrain integration. The end result after the four-year effort was a 362-lb, 2.8-liter engine with an aluminum block, head and oil pan, a magnesium valve cover and an engine-mounted emissions control system. The ATLAS engine, including the on-engine aftertreatment system, weighs in at approximately 80 lb lighter than the original all-aluminum gasoline V8.
The Highway Fuel Economy Test (HFET) and FTP-75 Test (city) cycles demonstrated fuel economy over 35 mpg and 25.5 mpg, respectively. This is approximately a 53% increase in CAFE fuel economy at 28.9 mpg, as compared with the production gasoline V8 fuel economy of 18.9 mpg. The engine also met the Tier 2 Bin 2 emission standards for criteria pollutants.
One of the most notable features of the ATLAS engine is the aluminum block, said Cummins. While not visible from outward appearances, the engine is a through-bolt design with a structural cradle above the oil pan and another above the cylinder head, “sandwiching” the block and head and enabling very high cylinder pressure capabilities.
A “dual loop” EGR system with both low- and high-pressure circuits and switchable valve timing improve light load emissions output and allow for increased power density of the engine. The overhead camshaft is driven by belt-in-oil technology. This lubricated belt system is designed to last the life of the engine. The ATLAS engine also uses ceramic glow plugs, a high pressure common rail (HPCR) piezo-style fuel system complete with a Bosch® high-pressure pump and a VGT™ Turbocharger. The complete package is controlled by Cummins controls technology.
The emission aftertreatment system includes an SCRF device (a DPF coated with an SCR catalyst) developed by Johnson Matthey. A cold start catalyst (dCSC™), also by Johnson Matthey, adsorbs NOx and HCs after a cold start and releases them after the aftertreatment components have warmed up sufficiency to achieve high conversion efficiency.
In addition to the state-of-the-art diesel technology, the engine features an 8-speed ZF 8HP70 transmission that helps to achieve the fuel-economy improvement. The remainder of the truck’s original running gear was unchanged.
SAE International recognized the ATLAS team with the John Johnson Outstanding Research in Diesel Engines Award for their work, as published in the SAE paper 2013-01-0282, Thermodynamic Systems for Tier 2 Bin 2 Diesel Engines.
Final plans to officially close Project ATLAS include a ride-and-drive event and final presentation at the DOE’s 2015 Annual Merit Review, June 8-12 in Arlington, VA.
Source: Cummins