In 1991, the first website went online, and gas cost an average of $1.12 per gallon. That same year, 18-year-old Jennifer Rumsey, SM ’98, first walked into the office of John Wall ’73, SM ’75, ScD ’78, to begin an internship at Cummins, a global engine design and manufacturing company based in Indiana. Wall, then vice president of advanced heavy-duty engine development at Cummins, was already working with young people as the MIT educational counselor for local high school students—a role he continued to fill until he retired as Cummins’s chief technical officer in 2015.
That internship shaped Rumsey’s future career. “My first exposure to engines happened when I worked for Cummins as an intern the summer before I went to college, and every summer while I was getting my undergraduate degree,” says Rumsey, who recently succeeded Wall as Cummins’s chief technical officer. “I found a passion for research and development as an intern at Cummins,” she recalls. “I was fascinated by complex systems, especially those that combined mechanical, electrical, and chemical engineering.”
Wall’s own interest in engines can be traced to the early 1970s, when he got a call from former roommate Leroy Besone, SM ’72, a mechanical engineer who’d recently returned to his job at Chevron Research in San Francisco. “One day he called me up and asked if I wanted to be an intern there that summer,” Wall says. “I said ‘Give me about two seconds to think about this’ and then went out to work in the engine lab at Chevron for two summers.”
In 1975, Wall joined the Sloan Automotive Lab under Professor John Heywood SM ’62, PhD ’65, for his ScD—as a Cummins Fellow. Heywood was researching the mechanics of engine pollution. The EPA had just been formed, and many people were interested in solving the newly identified emissions problem.
Wall earned his ScD in 1978 and then went back to work at Chevron. “With that group we discovered the effect of fuel sulfur on diesel particulate emissions,” he says. “It really helped us begin to build that bridge between engine technology, fuel technology, and atmospheric particulate emissions.” Then, in 1986, he got a call from Cummins.
“At Cummins, I got the opportunity to work on emissions from an engine technology standpoint, and that’s pretty much what I’ve been doing ever since,” he says. “In early emissions meetings with the EPA and fuel companies to negotiate future diesel-fuel sulfur limits, I had the funny situation where I had done the research at Chevron, and the data that the oil companies were bringing in to talk to us engine companies about was actually my data.”
Wall’s first major challenge at Cummins was controlling nitrogen oxide emissions by reducing the temperature of combustion, and the solution he and his team developed was a significant innovation. Later, in the early 1990s, he and his team applied new electronic fuel systems that allowed unprecedented flexibility in system design, as well as computer models that provided a better view of the fluid mechanics inside an engine.
Around that time, Wall first saw Rumsey’s technical capability and interest. “It has been interesting to watch Jennifer’s career develop,” he says. “I am very excited to have someone coming into this role of CTO who is so experienced with engines and exhaust after-treatment systems, but also so knowledgeable about new technologies that will help lead to a cleaner environment and new sources of energy.”
After Rumsey earned her bachelor’s in mechanical engineering from Purdue University and her master’s degree from MIT in mechanical engineering, she worked at Cambridge-based Nuvera, a company that specializes in fuel processing and fuel cells. In 2000 she moved to Cummins, where she’s worked in a variety of engineering roles for its engine and components business units, including advanced technology development, new product development, and current product engineering.
“John Wall had a major role in transforming Cummins products and emission technology in our industry,” Rumsey says. “I intend to build on his legacy and develop that next generation of breakthrough innovations. We have a big focus on creating an environment where our global technical organization can work together to solve some of the world’s biggest challenges.”
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