Engine On A Chip Promises To Best The Battery

MIT researchers are putting a tiny gas-turbine engine inside a silicon chip about the size of a quarter. The resulting device could run 10 times longer than a battery of the same weight can, powering laptops, cell phones, radios and other electronic devices.

Their microengine is made of six silicon wafers, piled up like pancakes and bonded together. Each wafer is a single crystal with its atoms perfectly aligned, so it is extremely strong. [...] They make 60 to 100 components on a large wafer that they then (very carefully) cut apart into single units.

Inside a tiny combustion chamber, fuel and air quickly mix and burn at the melting point of steel. Turbine blades, made of low-defect, high-strength microfabricated materials, spin at 20,000 revolutions per second -- 100 times faster than those in jet engines. A mini-generator produces 10 watts of power. A little compressor raises the pressure of air in preparation for combustion. And cooling (always a challenge in hot microdevices) appears manageable by sending the compression air around the outside of the combustor.

"So all the parts work.... We're now trying to get them all to work on the same day on the same lab bench," Epstein said. Ultimately, of course, hot gases from the combustion chamber need to turn the turbine blades, which must then power the generator, and so on. "That turns out to be a hard thing to do," he said. Their goal is to have it done by the end of this year.

Now the geeks will covet gasoline laptops to go along with their electric cars! But obviously this is not nearly as cool as powering your cellphone on human blood.

Tags: ,

22 Responses:

  1. merovingian says:

    Wow, awesome technology. I find myself liking Epstein immediately.

  2. mackys says:

    The matchbox-sized motor generates the equivalent of 100 watts, including the power electronics interface, and has an efficiency of close to 95 percent. Powered by a gas turbine, one tankful of fuel drives the generator for about 10 hours at peak 100 watt performance.

  3. lars_larsen says:

    I'd rathar have one of these things in my model airplane than in my laptop.

  4. violentbloom says:

    if only they'd used a flux capacitor instead of a non-renewable resource...

    • jamie_f says:

      Hey, this is just a stepping stone to the biodiesel version. Just shove eda mame in through the converted port that used to be for FireWire, and it becomes soybean oil. Make sure not to block the mulch exhaust port, though.

  5. zzedar says:

    "Each wafer is a single crystal with its atoms perfectly aligned, so it is extremely strong."

    I'm about ninety-five percent certain that this doesn't mean anything.

    • "Single crystal" and "extremely strong" are true; getting rid of grain boundaries strengthens materials by quite a bit (an order of magnitude in some cases). And of course they're perfectly aligned, there's nothing to interrupt the lattice.

      • Actually, getting rid of grain boundaries weakens many materials (eg common engineering metals like iron) quite a bit, by allowing slip dislocations to propagate more freely. Much of the processing that goes into producing good steel is to get a nice fine grain structure.

        (If you're making an object small enough, the tradeoff presumably changes; but you need single-crystal silicon for chip-style fabrication techniques anyway.)

  6. strspn says:

    Deja vu! Berkeley had an actual working gas engine this size five years ago. Detail PDF. IIRC commercialization hasn't happened yet because heat is a bigger problem than the MIT quotes suggest.

  7. usufructer says:

    10000 RPM is incredibly slow for a turbine of that size. Small turbines used in motorcycle turbochargers are capable of going over 200k RPM.

  8. jason0x21 says:

    I'm curious as to how many people will be more comfortable carrying around little bottles of flammable fuel rather than a power adapter.

    And lets not even talk about trying to get that on a plane.

    And long meetings will have a little can, right next to the coffee, that people can pass around as need be.

    It makes the blood fuel cell look positively practical.

    • mackys says:

      And lets not even talk about trying to get that on a plane.

      Yeah, choking on the hot CO2 and soot this thing throws out doesn't sound like a good time. The only way I see around the problem is if it runs on pure hydrogen... in which case the fuel cell is going to be a lot more efficient anyway.

      These microturbines are neat, but I wouldn't recommend them for use indoors.