The power source for tomorrow's laptop computers and cellular phones may have more in common with car engines than conventional batteries.
World's smallest rotary internal combustion engine. UC
(Click for larger image.)
Mechanical engineers at UC Berkeley's Combustion Processes Laboratories have built the world's smallest rotary internal combustion engine. Not much larger than a stack of pennies, the steel mini-engine can keep a bicycle headlight lit for two hours on just a shot glass full of liquid hydrocarbon fuel like butane or propane.
The mini-engine is only the first step toward development of a "micro-engine" the size of a single letter on a penny, fashioned in a process similar to the way microprocessors are etched from silicon.
"On the one hand, all this has created more problems that we have to solve," says mechanical engineering professor Carlos Fernandez-Pello. "On the other hand, we are developing a new field."
Fernandez-Pello developed the mini-engine with Kenji Miyaska of Fukui University in Japan, UC Berkeley post-doctoral researcher David Walther, and graduate students Kelvin Fu, Aaron Knobloch, and Fabian Martinez. According to Fernandez-Pello, the next-generation mini-engine, slated for completion before the end of this year, will be twelve times more powerful than the prototype. And thanks to the high energy density of liquid hydrocarbon fuel, the new engine will weigh the same as a traditional battery found in a mobile phone or digital camera, while running ten times longer before needing a fill-up.
"What started out as a scientific tool has become a marketable device," Fernandez-Pello says.
(For more on the mini-engine see the 2001 issue of Forefront magazine, available from the College of Engineering Public Affairs Office, 510-642-5857.)
Combustion Process Laboratories: www.me.berkeley.edu/cpl