Editor’s note: This is part of a series of articles linking the work of MIT’s emeritus faculty members with the current state of research in their given fields.
When it comes to understanding the inner workings of the engines that propel most of the world’s cars and trucks, John Heywood SM ’62 PhD ’65, MIT’s Sun Jae Professor of Mechanical Engineering, Emeritus, wrote the book: His textbook, Internal Combustion Engine Fundamentals (McGraw Hill), which has sold more than 100,000 copies worldwide since its publication in 1988 after a dozen years of work, has become the standard text in the field.
While many people today see internal combustion engines as dinosaurs that are on their way out, rendered obsolete by global warming and the escalating price of oil, Heywood sees them as something we’ll be living with for a long time to come — having learned how slowly habits change when it comes to something as ubiquitous in people’s lives as the cars they drive. That said, over the years the focus of his research has shifted away from how to make the engines work better and toward what measures — whether public policy, economic incentives, education or technological alternatives — will be most effective in helping to wean people away from them.
Heywood, who grew up in England as the son of a professor of mechanical engineering, came to MIT in 1960 to pursue a master’s degree. He figured he would head back to Cambridge (the other one) for his PhD, but then he met Peggy Gilkerson, a Radcliffe student from South Dakota who would later become his wife. Since she was continuing her studies here, he decided to stay on to work on his doctorate.
And that’s when he began delving into a question that has been a central feature of his life’s work: “What happens inside cars that contributes to air pollution?” It turned out, he says, that this was a relatively new and unstudied topic that had not been the subject of much research but was quite timely.
MIT’s Sloan Automotive Laboratory, where his work has been based, was founded in 1929 by Alfred P. Sloan, who was then president of General Motors. Heywood, who became its director in 1972, shifted its orientation from improving engine performance toward studying automotive emissions and how to control them.
Throughout its history, the lab has worked closely with industry — car and truck makers and petroleum companies — to address problems and research areas that were too broad or long-term in scope for the companies’ own research teams to address. The companies benefit from research findings they receive through meetings at the lab three times a year, and the students benefit from frequent interactions with industry researchers and visits to the companies’ facilities.
Responding to changing needs
Early on, Heywood began working closely with a younger colleague, Wai Cheng, who upon Heywood’s partial retirement in June 2009 replaced him as the lab’s director. Cheng says the lab’s work has evolved over the years, sometimes in a cyclic fashion, as both technologies and society’s needs have changed. In the early years, one hot topic was how to overcome knock in engines, which results when some of the fuel inside a cylinder ignites at the wrong time or in the wrong place, and can cause unwanted noise and stress and in severe cases can damage the engine. The introduction of tetra-ethyl lead solved that problem, and attention turned to other issues. But when the Environmental Protection Agency banned lead from gasoline in the 1980s, engine knock became an issue again. Other approaches resolved the problem, but now it is surfacing again because engines are being pushed to higher performance and smaller sizes in the interest of fuel economy.
Heywood says the lab has increasingly focused on broader issues of fuel consumption and global emissions, from both “a technology perspective and a strategy perspective,” he says, examining “how you could improve the situation, with new technologies, and using vehicles differently.”
He started to include policy analysis in his work after the National Science Foundation in the 1970s asked him how the government should encourage the development of alternative engines for transportation. Since then, and especially over the last decade, he has spent an increasing portion of his time on such questions.
When it comes to controlling emissions, now that catalytic converters do such an effective job of controlling most pollutants, the studies are increasingly zooming in on the beginning of the combustion process, before the converter has warmed up enough to work effectively. “Most of our research focuses on the first 10 seconds” of an engine’s operation, Cheng says, because that’s when it produces most of its emissions. Once the catalytic converter reaches its operating temperature “it reduces emissions by a factor of 100,” he says, “but before it’s warmed up, it’s useless.”
Heywood’s own work since he passed on the leadership of the lab has shifted from teaching and research to full-time research. “What I’m doing now is basically continuing all my research activities on the technology, relative to engines and fuel, and broader studies” of the social issues surrounding their use, and how to shift consumer behavior in their choices of vehicles and their driving patterns.
The challenge ahead
That research has resulted in two major reports in the last couple of years: “On the Road in 2035,” published in 2008, and “An Action Plan for Cars,” published in December 2009. Both of these reports examined a variety of different policy ideas, including such things as automotive efficiency standards, increases in gasoline tax, subsidies for biofuels, and so on, and came up with “a package of policies that we think can have some positive synergies.” If adopted, such policies could help to reduce the nation’s greenhouse-gas emissions and its dependency on petroleum imports — but perhaps not by as much as some people imagine, Heywood says.
“It’s not going to happen fast,” he says, given how long people keep their cars and how slow they are to make significant changes in driving or buying habits. “It takes a long time to achieve a major transformation” in technologies, he says.
All of the technological options for making major inroads in reducing petroleum usage — electric cars, biofuels, fuel cells and so on — will involve changing large-scale infrastructure as well as consumer habits, and that will be hard, he says. Even the simplest changes will occur slowly, Heywood says. “We can do with much smaller cars, and we’ll go down that path grudgingly, as needed. We’ll fight to the last breath before doing that. It will take clear incentives and pressures.”
But it’s not all bad news. Among the lab’s findings is that, while people think of internal combustion engines as a mature technology with little room for significant improvements, in fact progress has been surprisingly steady: From 1980 to 2000, average automotive efficiency improved by about 1.5 percent per year.
There’s also one potential solution requiring no technology that could make a big difference, Heywood says: driver education. “Europe is moving ahead with the concept of eco-driving,” he explains. Basically, that consists of avoiding aggressive driving such as fast acceleration from a stop and constant variations of speed, which can be a surprisingly big fuel waster. Providing more real-time information about fuel consumption, as many hybrid vehicles do, can make a big difference on driving styles.
Using fuel more efficiently, through better technology and better driving habits, will continue to be critical for a long time, Heywood suggests. While some people think conventional engines are nearing the end of their dominant position in the world’s transportation systems, Heywood, who at 72 has seen the rise and fall of numerous attempts to push transportation in different directions, thinks internal combustion engines will not only continue to dominate but even to grow. There are about 800 million vehicles in the world today, he says, and that number could reach 2 billion within a few decades — with the majority likely still powered mostly or entirely by petroleum.
But with the pressing problem of global climate change, and with petroleum supplies becoming ever more expensive to recover, the world can’t afford to wait to change things, Heywood says. Petroleum usage needs to drop, and that means we need to be shifting rapidly towards more fuel-efficient cars and trucks, more hybrids, and possibly more biofuels. Typically, major changes in transportation systems have taken about 50 years to take hold, but this time changes need to happen more rapidly. “We have another 25 years to achieve a major transition — not to start it, but to achieve it,” he says.