When we launched ATLAS, the team understood that they had to think outside the box to achieve our targets. Specifically, we knew that weight reduction, advanced emissions control technologies, advanced thermal management and powertrain integration would be critical to meeting all of the requirements. The challenge was making those significant advancements while ensuring that the engine we produced would be commercially viable.

—Michael Ruth, Director/Technical Project Leader, Advanced Light-Duty

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 gasoline-fueled V8, so maintaining a torque output of 385 lb-ft (522 N•m) was necessary. The Cummins team chose a 4-cylinder ISF 2.8 base engine to begin research, and from there, the evolution began.

The end result after the four-year effort was a 362 lb (164 kg), 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 (36.3 kg) lighter than the original all-aluminum gasoline V8.

The Highway Fuel Economy Test (HFET) and FTP-75 Test (city) cycles demonstrated fuel economy above 35 mpg (6.72 l/100 km) and 25.5 mpg (9.22 l/100 km), respectively. This is approximately a 53% increase in CAFE fuel economy at 28.9 mpg (8.14 l/100 km), as compared with the production gasoline V8 fuel economy of 18.9 mpg (12.45 l/100 km). The original ATLAS project fuel economy targets were 22.4 mpg city and 34.3 mpg highway.

The ATLAS engine uses advanced technologies to meet the future regulations. One of the most notable features is the aluminum block. 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 Exhaust Gas Recirculation (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.

Another feature is the engine-mounted aftertreatment. In partnership with Johnson Matthey, an on-engine catalyst was developed that has Selective Catalytic Reduction (SCR) wash-coat technology applied directly to the particulate filter.

In addition to the advanced diesel technology, an 8-speed ZF 8HP70 kept the engine operating at an optimum speed, helping to achieve a more than 50 percent fuel-economy improvement over that of the gasoline V8. The remainder of the truck’s original running gear was unchanged.

Although the ATLAS engine is a research project, it was subject to all of the design standards and rigorous testing that Cummins performs on all products to ensure that the customer is receiving the most dependable and durable diesel engine available. On-road testing, towing, cold weather and chassis dyno testing, to verify that the ATLAS 2.8L met the U.S. emissions standards it was being measured against, resulted in a successful proof of concept.

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 “Thermodynamic Systems for Tier 2 Bin 2 Diesel Engines”.

Cummins will officially close Project ATLAS with a ride-and-drive event and final presentation at the DOE’s upcoming 2015 Annual Merit Review in June.

Resources

• Suresh, A., Langenderfer, D., Arnett, C., and Ruth, M. (2013) “Thermodynamic Systems for Tier 2 Bin 2 Diesel Engines,” SAE Int. J. Engines 6(1):167-183, doi: 10.4271/2013-01-0282