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The Race to 100 MPG
PopSci.com ^ | 9/1/2006 | Billy Baker

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.



TOPICS: Business/Economy; Miscellaneous; News/Current Events
KEYWORDS: diesel; energy; engine; gasoline; pollution
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Pretty cool looking.........
1 posted on 10/25/2006 7:13:53 AM PDT by Red Badger
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To: sully777; Toby06; vigl; Cagey; Abathar; A. Patriot; B Knotts; getsoutalive; muleskinner; ...
KNOCK-KNOCK!........

If you want on or off the DIESEL "KNOCK" KIST just FReepmail me........

2 posted on 10/25/2006 7:14:43 AM PDT by Red Badger (CONGRESS NEEDS TO BE DE-FOLEY-ATED...............................)
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To: Red Badger

Seal issues. Think Wankel.


3 posted on 10/25/2006 7:15:22 AM PDT by Steely Tom
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To: Steely Tom

I don't wank seals..........


4 posted on 10/25/2006 7:15:55 AM PDT by Red Badger (CONGRESS NEEDS TO BE DE-FOLEY-ATED...............................)
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To: Red Badger

That compressor doesn't look very efficient.


5 posted on 10/25/2006 7:16:38 AM PDT by lesser_satan (EKTHELTHIOR!!!)
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To: lesser_satan

Looks can be "deceiving", lesser_satan.........


6 posted on 10/25/2006 7:17:44 AM PDT by Red Badger (CONGRESS NEEDS TO BE DE-FOLEY-ATED...............................)
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To: Red Badger

It's actually not all that dissimilar from a rotary engine that Mazda RX-7s and RX-8s have.


7 posted on 10/25/2006 7:17:53 AM PDT by JamesP81 (The answer always lies with more freedom; not less)
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To: lesser_satan
http://www.starrotor.com/

Above is the URL of star rotor which explains how it works.
Great graphs and diagrams.
8 posted on 10/25/2006 7:20:12 AM PDT by HuntsvilleTxVeteran ("Remember the Alamo, Goliad and WACO, It is Time for a new San Jacinto")
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To: Red Badger

I think you blew a seal,

no it's just ice cream


9 posted on 10/25/2006 7:27:22 AM PDT by edzo4
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To: Red Badger
I don't wank seals..........

LOL...or blow them.

10 posted on 10/25/2006 7:27:48 AM PDT by Lekker 1 (("...the world will be...eleven degrees colder by the year 2000" -- K. Watt, Earth Day, 1970)
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To: Red Badger

Look promising, of course the proof is in the pudding. They need a working prototype, and need to prove its efficiency in typical automotive use, plus it has to have similar longevity compared to todays piston engine. I wish them the best.


11 posted on 10/25/2006 7:29:00 AM PDT by Paradox (American Conservatives: Keeping the world safe for Liberalism.)
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To: Red Badger

This is a standard turbine engine with a positive displacement compressor and turbine instead of centrifugal. The heat recuperator is nothing new either. Actually, I have often wondered why there hasn't been more development in this technology before.


12 posted on 10/25/2006 7:30:29 AM PDT by Lekker 1 (("...the world will be...eleven degrees colder by the year 2000" -- K. Watt, Earth Day, 1970)
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To: Red Badger
For comparison, other "concept" engines:

Revtec:
http://www.freerepublic.com/focus/f-news/1505350/posts

MYT:
http://www.freerepublic.com/focus/f-chat/1621112/posts

An old one, the Bourke engine (claims 300% more efficiently than 4 stoke engines):
http://peswiki.com/index.php/Directory:Bourke_Engine
13 posted on 10/25/2006 7:31:53 AM PDT by Pete from Shawnee Mission
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To: Red Badger
MASH HERE and discuss.
14 posted on 10/25/2006 7:32:51 AM PDT by isthisnickcool (The City Council of Houston Texas is made up mostly of retards.)
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To: Red Badger

Um...

If it's in production why isn't anyone using it?

If it's in development why would they broadcast their invention before production?


15 posted on 10/25/2006 7:32:53 AM PDT by HarleyD ("Then He opened their minds to understand the Scriptures" Luk 24:45)
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To: JamesP81

The key differences from a wankel that I see are that the combustion takes place away from the moving parts, and the compression and the expansion take place in separate mechanisms. It seems that the "seal" issues of the Wankel may not be as much of an issue here.


16 posted on 10/25/2006 7:34:40 AM PDT by Lekker 1 (("...the world will be...eleven degrees colder by the year 2000" -- K. Watt, Earth Day, 1970)
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To: isthisnickcool
From their webpage...

I guess I answered my own question.
17 posted on 10/25/2006 7:36:46 AM PDT by HarleyD
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To: Red Badger

Looks to me like one of those jet engines you make from an old automobile turbocharger. Just hook a drive shaft up to it...


18 posted on 10/25/2006 7:40:09 AM PDT by Bon mots
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To: Red Badger

What's the bid geal with 100mpg? My mother drives a diesel Citroen C1 which does 83mpg at a steady 56mph. On gentle runs she's got nearly 90mpg. . . . .


19 posted on 10/25/2006 7:40:39 AM PDT by AngloSaxonChristian
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To: Steely Tom
Seal issues. Think Wankel.

Yup... and Wankels are not very fuel-efficient engines to begin with, compared to piston engines of similar horsepower. It looks like they've managed to recapture some waste heat and use it, upping the efficiency, but these claims sound terribly speculative.

Also, what's with the "the exhaust spins the rotor that drives the wheels" part? That sounds a lot like the old Chrysler Turbine setup. The diagram shows no connection between the compression and drive rotors, not even a viscous coupling. The vehicle better be small and light, because I suspect this design will share another Wankel characteristic - low torque. Efficiency is great, but if it can't do the work...

20 posted on 10/25/2006 7:46:21 AM PDT by Charles Martel (Liberals are the crab grass in the lawn of life.)
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To: Red Badger

Isnt this pretty much a turbine engine? Chrysler tried that once and failed.


21 posted on 10/25/2006 7:54:16 AM PDT by sgtbono2002 (The fourth estate is a fifth column.)
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To: Charles Martel
"The diagram shows no connection between the compression and drive rotors, "

There is a direct connection!



http://www.starrotor.com/index.htm
22 posted on 10/25/2006 8:05:56 AM PDT by HuntsvilleTxVeteran ("Remember the Alamo, Goliad and WACO, It is Time for a new San Jacinto")
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To: sgtbono2002
Yes, 40 years ago.

Do not make the same mistakes that the environmentalist make in using old data.

The M1 tank is turbine powered (yes it is not very fuel efficient, 80 ton vehicles seldom are) as are several modern types of war ships.

The problem with turbines is that they use X amount of fuel per hour. Whether they are moving or not. (NOTE: You can burn more than X amount of fuel to increase power or even add on a secondary combustion chamber and use even more fuel but you always use a rather large minimum amount) Also they generate a lot of waste heat.

The problem with the Chrysler turbine was durability, the engine did not last long. A car engine usually last about 3000 hours before a major rebuild(diesels can go 10,000+), but a turbine requires major maintenance every few 100 hours.

The materials to make turbines that can withstand the high heat are also expensive.

Where this engine might have use is in a turbine-electric drive system. This turbine drives a generator which drives an electric motor. Batteries are used for high discharge situations.
23 posted on 10/25/2006 8:17:34 AM PDT by fireforeffect (A kind word and a 2x4, gets you more than just a kind word.)
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To: Red Badger

That's awesome.


24 posted on 10/25/2006 8:18:42 AM PDT by mysterio
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To: Steely Tom

"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.


25 posted on 10/25/2006 8:22:05 AM PDT by FastCoyote
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To: HuntsvilleTxVeteran
Okay, I see it now (had to click the image to see the animation). I had it turned around... the drive rotor is actually the portion that takes combustion energy and turns it into rotation.

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.

26 posted on 10/25/2006 8:42:45 AM PDT by Charles Martel (Liberals are the crab grass in the lawn of life.)
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To: FastCoyote

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.


27 posted on 10/25/2006 8:54:56 AM PDT by FastCoyote
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To: Red Badger

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.


28 posted on 10/25/2006 8:57:12 AM PDT by RightWhale (Repeal the law of the excluded middle)
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To: RightWhale

Or overcome gravity.


29 posted on 10/25/2006 8:59:52 AM PDT by bmwcyle (Only stupid people would vote for McCain, Warner, Hagle, Snowe, Graham, or any RINO)
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To: RightWhale

Tunnels straight thru the earth with 4 quadrant mag lev rails.........


30 posted on 10/25/2006 9:00:14 AM PDT by Red Badger (CONGRESS NEEDS TO BE DE-FOLEY-ATED...............................)
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To: bmwcyle

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%


31 posted on 10/25/2006 9:02:55 AM PDT by RightWhale (Repeal the law of the excluded middle)
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To: Red Badger

Winkle, winkle, little wankle. Whats all of those RPMs you'll crankle.


32 posted on 10/25/2006 9:03:19 AM PDT by lmailbvmbipfwedu
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To: Red Badger
Honda has a diesel Accord that can reach 90+mpg.....

http://www.carpages.co.uk/honda/honda_diesel_sets_new_world_records_12_05_04.asp

33 posted on 10/25/2006 9:04:47 AM PDT by getsoutalive
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To: fireforeffect
but a turbine requires major maintenance every few 100 hours

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.

34 posted on 10/25/2006 9:06:28 AM PDT by thackney (life is fragile, handle with prayer)
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To: sgtbono2002

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.


35 posted on 10/25/2006 9:19:46 AM PDT by Richard-SIA ("The natural progress of things is for government to gain ground and for liberty to yield" JEFFERSON)
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To: Richard-SIA

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.


36 posted on 10/25/2006 9:50:16 AM PDT by sgtbono2002 (The fourth estate is a fifth column.)
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To: Red Badger
One of the problems that Turbine engines had was low end torque was very poor.

I often thought if they had an electric motor to get it up to speed, the turbine could take over/"join in"...and there is NO reason the turbine couldn't supply the charging of batteries. I thought this in the 70s well before they had the battery charging tied to the wheels and braking.
37 posted on 10/25/2006 10:00:26 AM PDT by Jackson Brown
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To: fireforeffect

Makes sense to me. perhaps a small engine could provide electric power and get good mileage.


38 posted on 10/25/2006 10:01:33 AM PDT by sgtbono2002 (The fourth estate is a fifth column.)
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To: FastCoyote
"thermodynamically you want cold/dense air coming in."

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.

39 posted on 10/25/2006 10:01:38 AM PDT by avg_freeper (Gunga galunga. Gunga, gunga galunga)
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To: FastCoyote
"You'd end up with the same problem, one hell of a lot of heat."

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.

40 posted on 10/25/2006 10:04:34 AM PDT by avg_freeper (Gunga galunga. Gunga, gunga galunga)
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To: Lekker 1

You'll like this ....http://www.turbinecar.com/top.swf


41 posted on 10/25/2006 10:08:53 AM PDT by mo
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To: Steely Tom

Nope. More like the gas turbine engine......


42 posted on 10/25/2006 10:34:07 AM PDT by Schwaeky (Welcome to America--Now speak English or LEAVE!)
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To: sgtbono2002

It wasn't a failure, it was very much a success, unfortunately, big oil and the Big Four shelved the idea and took the cars back, pretty much destroying the majority of them, the few remaining examples are in museums, but it had a very successful run. Unfortunately they did with the Chrysler turbine what GM did with the EV1 (leased out to people, then recalled them). The Chrysler Turbine was very efficent for its day, doing a then outstanding 30 mpg in city driving, with some minor tuning capable of 45+mpg. That in a vehicle that weighs as much as a modern hearse.


43 posted on 10/25/2006 10:38:41 AM PDT by Schwaeky (Welcome to America--Now speak English or LEAVE!)
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To: edzo4

"I think you blew a seal."

"Just fix the damn thing and leave my personal life out of this!"

/kooky song mode


44 posted on 10/25/2006 10:47:19 AM PDT by MortMan (I was going to be indecisive, but I changed my mind.)
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To: mom4kittys; ctyankee00; Hegemony Cricket; JamesP81; Millee; wingnut1971; sully777; Toby06; ...
Automotive Ping List
· Automotive Ping List · join list & same if you want off




!!!Ping!!!

45 posted on 10/25/2006 10:52:40 AM PDT by sully777 (You have flies in your eyes--Catch-22)
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To: Red Badger
Tunnels straight thru the earth with 4 quadrant mag lev rails.........

Cool, as long as a portal is near my house, but not in y bak yard. Maybe the next town over, in someone elses back yard.

46 posted on 10/25/2006 10:56:32 AM PDT by Toby06 (Diesel smoke makes me horny.)
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To: RightWhale

>Gravity is not the problem. It is fully restorative. >Maybe there is another word to carry that meaning...

The other word is actually 'conservative'!

Gravity is a conservative force, in that it conserves energy.


47 posted on 10/25/2006 11:37:21 AM PDT by chipengineer
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To: chipengineer

What is the proper Republican stance on gravity, a conservative field?


48 posted on 10/25/2006 11:52:24 AM PDT by RightWhale (Repeal the law of the excluded middle)
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To: RightWhale

We should be in favor of gravity.

Without it, people keep flying off the handle, like democrats.


49 posted on 10/25/2006 11:56:15 AM PDT by thackney (life is fragile, handle with prayer)
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To: thackney

Nat gas is up 60 cents today. Retail gasoline has finally declined a few cents in Fairbanks just in time for the wholesale gasoline index to pop up ten cents. We got some snow a couple days ago that stuck and it is fun to watch the chechakos try to drive their Trans-Ams and 454 Silverados the first day--a good day to stay home.


50 posted on 10/25/2006 12:04:09 PM PDT by RightWhale (Repeal the law of the excluded middle)
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