Posted on 10/25/2006 7:13:52 AM PDT by Red Badger
Jet-Engine Inspiration Another potential player in the race to 100 mpg is the StarRotor, which began life as an air conditioner at Texas A&M University. Chemical-engineering professor Mark Holtzapple and his colleague Andrew Rabroker were attempting to build a better compressor for an air conditioner when they hit on the idea that became the StarRotor engine’s basic architecture. Once they made the connection to car engines, “we quickly forgot about air conditioners,” Rabroker says. They have since formed a business (also called StarRotor) to commercialize the technology.
The StarRotor uses the same thermodynamic process as jet engines to recuperate some of the heat normally lost to exhaust, something that the design of a piston engine doesn’t allow. The exhaust heat warms the air that comes into the engine before the fuel is added [see illustration, below]. This hot air leads to more powerful combustion, which means the StarRotor can extract more energy from a given amount of fuel than a conventional engine could.
Stephen Rountree
Intake air is compressed [A] and heated [B] before it ignites in the combustor [C]. The exhaust spins the rotor [D] that drives the wheels. It then warms the heater [E].
Based on data from compressor prototypes, Rabroker believes the StarRotor will convert between 45 and 65 percent of the chemical energy in its fuel to mechanical energy, irrespective of the engine’s operating speed or power. In contrast, a typical gasoline engine has a peak efficiency of about 30 percent at full throttle and operates at a much lower efficiency during typical driving conditions. “Double is a gimme,” Rabroker says of the StarRotor’s potential. “I think we can ultimately triple the fuel mileage.”
Double or triple, though, what’s important is that innovators are developing solutions to our oil predicament —solutions that could have a huge influence before the first hydrogen-powered car ever leaves the lot.
When Billy Baker isn’t writing about the automotive industry, he’s working on a book about the juggling subculture.
Isnt this pretty much a turbine engine? Chrysler tried that once and failed.
That's awesome.
"The exhaust heat warms the air that comes into the engine before the fuel is added [see illustration, below]. This hot air leads to more powerful combustion, which means the StarRotor can extract more energy from a given amount of fuel than a conventional engine could."
While heating intake air increases atomization (Richard Petty), thermodynamically you want cold/dense air coming in. Otherwise supercharger intercoolers wouldn't be used. Add to that the seal problems.
Not saying it won't work (yet), just saying your milage may vary somewhere less than utopia.
The "separate" combustion chamber sort of threw me. It makes more sense if you think of the combustor as part of the drive rotor assembly, which it is (albeit not in a familiar sense).
This thing really is sort of a combination of a Wankel and a jet turbine. I wish them luck with it - should make an interesting aircraft engine, if nothing else.
On further inspection, I see they are judt running a recuperator. You could do the same thing by taking a V8, using 4 pistons for compression and 4 for 2 stroke combustion with a recuperator. You'd end up with the same problem, one hell of a lot of heat.
There is no reason why transportation to anywhere on earth and back should have to consume any energy at all. Get to work on the friction thing.
Or overcome gravity.
Tunnels straight thru the earth with 4 quadrant mag lev rails.........
Gravity is not the problem. It is fully restorative. Maybe there is another word to carry that meaning, but you get it all back when you get home. 100%
Winkle, winkle, little wankle. Whats all of those RPMs you'll crankle.
http://www.carpages.co.uk/honda/honda_diesel_sets_new_world_records_12_05_04.asp
That depends on the turbine. Many, many industrial turbines operate 10,000 hours or more before shutting down for any maintenance at all. Nearly all operate continuously for years before any major maintenance is performed. This type of application is typical for a Natural Gas Pipeline or other similar service.
Tried and failed?
Not really, more like the car was a success, so long as mileage was not a concern, and many of the test drivers wanted to keep the cars.
Chrysler and Rover both had technically successful turbine cars, and both simply chickened out.
They ate up fuel at a fantastic rate, but they burned most anything,including Fry fat, I believe they had a lot of trouble braking the thing and it wouldnt get off the line very well. Acceleration was slow and they didnt have much pulling power.
Makes sense to me. perhaps a small engine could provide electric power and get good mileage.
That's exactly right and what I thought when I started reading this.
But if you go to the website you find out that the fuel-air mixture is heated after the compressor stage. Makes a little more sense now.
From their website:
To create an even more efficient engine, atomized liquid water can be sprayed into the compressor inlet to keep the compressor cool. Keeping the compressor cooler allows compression to be more efficient thus the engine will be more efficient.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.