Excerpted with permission from the University of Windsor.
Anyone who has ever stood on the street corner of a busy intersection of a hot Caribbean city has probably experienced the malodorous and choking effect of exhaust fumes as diesel-powered buses and cars whiz by. And if they have even a hint of environmental consciousness, those pedestrians have likely remarked on how the diesel fumes must be contributing to the greenhouse gases that so many scientists argue are contributing to climate change.But if Dr. Ming Zheng had his way, there would be a many more diesel-powered vehicles on the road and fewer traditional combustion engines.
Known globally in both academic and industrial circles as “Mr. Clean Diesel,” Zheng has established a $3 million laboratory at the University of Windsor’s Centre for Automotive Research and Education (CARE), which has become the envy of institutions worldwide. He is devoted to improving diesel engines by maximizing their efficiency and reducing their emissions.
“The diesel produces much less carbon dioxide than the regular combustion engine and it’s much more efficient,” says Zheng. “The higher the fuel efficiency, the lower the carbon dioxide emissions.” He adds that diesels, which are making a comeback in the United States and are popular in Europe, are more powerful than combustion engine vehicles, and can be made cleaner.
Zheng’s lab, just a short walk from the university’s main campus, looks like something out of a science fiction movie. To the untrained eye, it appears to be nothing more than a massive web of thick wiring, tubing, and banks of computers, but to Zheng and the group of students who work with him, it’s a precise work of diagnostic art. “It’s a very sophisticated system,” says Zheng. “We’ve got 16 computers monitoring one engine, looking at factors such as fuel temperature, oxygen, coolant, oil, exhaust. It’s taking about 130 measurements simultaneously.”
And establishing the lab has allowed him to forge relationships with such industry heavyweights as Ford, Imperial Oil, and the International Truck and Engine Corporation, who are all keen in the potential of clean diesel technology.“We recently had a visit from Renault,” says Zheng . “They spent two hours here and they want to benchmark our lab.”
Zheng is primarily interested in combustion control and pollutant emission control, including in-cylinder emission control and exhaust after-treatment. The group has reconfigured a four-cylinder Ford common rail diesel engine to run in one-cylinder mode. By controlling and manipulating variables, such as fuel injection strategies with multiple fuel injection events per cycle, exhaust gas recirculation (EGR) levels and the engine boost level to the combustion cylinder, they have been able to simultaneously reduce nitrogen oxides and soot. However, this type of combustion is normally unstable and noisy. They hope to find ways to control the combustion of reducing emissions.
“We can generate up to eight fuel injections per engine cycle in order to reduce soot,” explains Usman Asad, a PhD student in Zheng’s lab. “But you have to strike a balance. By increasing the fuel injections per engine cycle, you also increase the carbon monoxide and hydrocarbon emissions.”
And treating diesel exhaust is much more complex, says Zheng. The exhaust fume temperatures from a diesel engine are much lower than those from a traditional combustion engine, so supplemental energy has to be added to the exhaust gases for a catalytic converter to function properly (i.e. hot enough to burn off excess, unburned fuel that would otherwise be disposed of by a catalytic convertor).
Finding the solutions to these complex problems motivates Zheng and his team in their pursuit to create an engine that can ultimately provide cleaner transportation for the future and in the process, help solve some of our planet’s environmental ills.
The infrastructure for this project was partially funded by the Canada Foundation for Innovation.