Sandia researcher Isaac Ekoto, left, and former postdoc Will Colban prepare to conduct laser-based velocity measurements at the Combustion Research Facility. The measurements are used to help understand the flow features involved in the creation of in-cylinder carbon monoxide distributions in automotive diesel engines. | Photo Courtesy: Sandia National Laboratory
In 1985, there was growing awareness of the environmental health risks posed by particulate matter (PM) and nitrogen oxide (NOx) emissions from diesel engines.
In response, the Environmental Protection Agency (EPA) released new diesel emission standards.
This was a step forward for the environment—but an enormous challenge for companies like Cummins, a leading manufacturer of diesel engines. At Cummins’ corporate headquarters in Columbus, Indiana, a team of engineers was tasked with developing a diesel engine that could meet federal requirements while retaining the same levels of horsepower and efficiency that consumers demanded.
This daunting task required a stronger understanding of the science behind the engine—not to mention computer-simulation capabilities that were far beyond those of Cummins. It also meant making substantial changes to Cummins’ manufacturing lines. With their work cut out for them, the team’s engineers knew just where to turn for assistance.
The Opportunity: Reducing Emissions while Maintaining Engine Quality and Efficiency
Cummins approached researchers at three of the national laboratories—Sandia National Laboratories (SNL), Los Alamos National Laboratory (LANL), and Lawrence Livermore National Laboratory (LLNL)—to discuss the possibility of a partnership. The labs possessed unique expertise in laser diagnostics and computer modeling and housed unique state-of-the-art facilities, including specialized measurement equipment and extremely fast supercomputers. Perhaps most importantly—they have renowned world-class expertise in their teams of lab scientists. Cummins would need all of these elements to meet the tighter emissions standards while staying economically competitive in the market.
The Pathway: A Crucial Collaboration for the Nation
In addition to the national laboratories, Cummins invited fellow competitors in the diesel engine market, Caterpillar and Detroit Diesel, to join the research group. A few years later, the group expanded to include Ford, General Motors, and Chrysler and reorganized under a Memorandum of Understanding (MOU), entitled “Advanced Engine Combustion Research Program.” The researchers in the MOU also partnered closely with U.S. Department of Energy (DOE)-funded research teams at the University of Wisconsin and University of Michigan.
“My hat’s off to Cummins,” said John Dec, a senior scientist at the Combustion Research Facility at SNL, who joined the project in 1989. “They invited others to join, so there were many more individuals involved. This was a great thing—it led to more rapid adaptation of the research to engine development, and more support for the advanced research at the labs.”
The Breakthrough: Advanced Laser and Computer Modeling Technology to Predict and Reduce Emissions
Dec led the effort at SNL in partnership with Patrick Flynn, then vice president of research and development (R&D) at Cummins. Over the decade that followed, the consortium performed cutting-edge diesel combustion research. At SNL, Dec and his team pioneered the application of laser-sheet imaging diagnostics to literally shed light on how and where soot and NOx form inside a diesel engine. This effort included the laser-imaging of fuel-jet penetration, fuel vaporization and mixing, and combustion zones.
Meanwhile, Cummins worked with LANL to adapt its computational fluid dynamics (CFD) code, known as KIVA, to better simulate diesel combustion. LLNL contributed to the effort, developing detailed mechanisms for complex chemical kinetic reactions occurring inside a diesel engine.
Although the team was initially working with a limited scientific understanding of diesel combustion, in 1997, two major breakthroughs occurred.
Combining results from multiple laser-imaging diagnostics that could probe the diesel combustion process in ways never before possible, Dec developed and published a research paper on a groundbreaking conceptual model for how diesel combustion occurred. For the first time, it was clear how fuel-mixing, combustion, and emissions-formation processes took place in a diesel engine. This breakthrough made it far easier for engine designers to design cleaner engines and develop computer models that could predict soot and NOx emissions.
Around the same time, Cummins engineers, led by John Wall—who would later go on to become the company’s chief technology officer—used LANL’s advanced CFD code to build a faster and more advanced computer-simulation capability that could better predict diesel combustion and emissions.
Combined, these two breakthroughs altered the direction of diesel engine design forever, guiding subsequent R&D of advanced computer-simulation capabilities—with the ultimate goal of providing quicker solutions for better performance, lower emissions, and a stronger fuel economy.
In 2007, Cummins, by assimilating research results from the national laboratories into its own computer models, achieved another major milestone: building the first diesel engine in the world designed completely by a computer, which worked seamlessly during its first prototype. Testing showed that this computer-developed design met or exceeded all emissions and performance goals. This revolutionary new capability reduced Cummins’ product development time and costs by an estimated 10%, creating a design considered superior to those produced by conventional techniques (and saving its customer, Chrysler, about $1,000 per engine).
To date, this new engine and its ultra-low emissions derivatives have been installed in 1.5 million Dodge Ram heavy-duty pickup trucks, delivering 20%–25% better fuel economy than the gasoline engine model. Cummins remains an industry leader in adapting to changing requirements. In fact, the diesel Dodge Ram, with Cummins’ engine and a Cummins-developed advanced after-treatment system, was the only diesel vehicle to meet the 2010 EPA standards for NOx emissions for medium- and heavy-duty diesel engines in 2007—three years ahead of schedule.
“The national labs are a powerful partner,” said Wayne Eckerle, Cummins’ vice president of research and technology. “They bring together a lot of industry partners in a way that we would never do alone. Normally, we are fierce competitors, but when there is a national lab initiative, it brings together the best and the brightest, and we can come up with better and more innovative solutions collectively than one single company.”
The Impact: Driving Environmental Improvements and Economic Prosperity
Cummins’ 30-year diesel engine R&D partnership with the national laboratories has led to successful commercialization of many versions of its heavy-duty and medium-duty diesel engines—advancing improvements in fuel efficiency while creating hundreds of American jobs in manufacturing, engineering, and research.
Wall and Eckerle credit the national laboratories with significantly shortening the product-development life cycle for many of Cummins’ products. Despite increased global competition, this accelerated process has helped Cummins and other U.S. diesel companies and auto manufacturers expand into international markets where their engines can now be installed faster and cheaper. For the past three years, approximately half of the company’s sales were generated outside the United States.
U.S. citizens have also reaped a significant return on their taxpayer dollars; a third-party study demonstrated that DOE investment in advanced diesel combustion R&D generated more than $70 billion in economic benefits, coming from less than $1 billion invested from 1986 through 2007.
Perhaps most important, there are enormous environmental benefits to having cleaner, more efficient diesel engines. Since the inception of the partnership between Cummins and SNL in 1985, diesel engine particulate emissions have been reduced by a factor of 100 and NOx emissions by a factor of 50.
Wall predicts continued growth in diesel engine designs that reduce greenhouse gas, particulate, and NOx emissions, without compromising their power.
“Our relationship with the national labs and the Department of Energy has been extremely important in helping us solve some critical problems,” Wall said. “They have been pivotal in fast-tracking breakthroughs in emission and fuel-efficiency technology, and helped us to understand the science behind our products with supporting analytical tools.” As vehicle technologies continue to advance into the marketplace, the future looks bright for cleaner ways for us to all arrive at our destinations.
