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New technology promising to cut CO2 and save gas

Alternative energy comes from unusual sources -- huge rivers, massive arrays of silicon panels, nuclear reactions, and massive spinning metal blades.   But German researchers are getting power from a source that might strike scientists from decades past as particularly peculiar -- they're making power from automobile exhaust gases.

In an era of ultra-expensive fuel and concerns about emissions fueling global warming, the automobile has come under increasing scrutiny with users looking for ways to extend gas mileage and cut emissions.  Fraunhofer-Gesellschaft, a leading German research organization, is developing materials and designs for a thermoelectric generator which will help to solve both problems.

In automobiles, two-thirds of the fuel used is emitted as waste heat. In total, 30 percent of the energy is lost in heat from the engine block and a further 30 to 35 percent is lost to exhaust fumes.  Many teams of researchers have began to look at how to recapture some of this heat and heat from similar industrial engines and transform it into electricity.  Such devices are known as
thermoelectric generators or TEGs for short.

The TEG generator takes a temperature gradient, driven by the difference between the waste heat and the ambient temperature and uses that gradient to produce electricity.  Greater temperature differences yield great results.  The
Fraunhofer Institute for Physical Measurement Techniques IPM has a number of thermoelectric materials under development that will harvest this heat in automobiles. 

Dr. Harald Böttner, head of the Thermoelectric Systems department states, "The temperatures in the exhaust pipe can reach 700 degrees Celsius or more.  The temperature difference between the exhaust pipe and a pipe carrying engine cooling fluid can thus be several hundred degrees Celsius."

thermoelectric converter the team is developing takes the gradient created by the exhaust gas and uses it to drive charge carriers through a semiconductor.  This creates a looped current flow similar to a battery.  The technology is relatively straightforward, but the real challenge is finding optimal thermoelectrics with high carrier mobility.  The research team is hoping that the device will make the alternator obsolete, providing power to the car's consumer electronics, onboard computers, and charging the battery.  Böttner states, "This would make it possible to cut gas consumption by between five and seven percent,"

Researchers point out that with 50 million cars on the road in Germany with an average on-road time of 200 hours a year per car, if only one kilowatt each was produced by the TEGs, this would amount to
ten terawatt hours per year. 

The researchers are hoping to begin to construct prototypes of their designs very soon.

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RE: Even better
By FITCamaro on 6/6/2008 3:39:07 PM , Rating: 5
That assumes that the gas engine is running. In a standard hybrid, yes it could charge the battery whenever the gas engine is running though.

In a vehicle like the Chevy Volt, this could have a huge impact. Because the engine only runs when its charging the battery. If this could be used to produce even more energy on top of what the gas engine/generator is, then the car would be even more efficient.

Honestly if they can get the Volt out at an affordable price, with decent performance, I might buy one. It's a pretty slick looking car. And it actually offers the range that a standard gasoline engine car offers (around 640 miles they're saying). The only bad thing I've heard about it is that supposedly the gas generator is designed to run on E85. E85 is only available at one local gas station (that I know of). So hopefully its efficiency is the same on 93 octane.

Some of you might say that E85 is less efficient in current cars than regular gas. But thats because they're mainly designed to run on gas, not E85. On an engine thats designed to run on E85, it might run worse on regular gas.

RE: Even better
By Ringold on 6/6/2008 3:55:35 PM , Rating: 4
I think it'll end up probably being close to 40k at the dealerships; thats a little high for me.. It does look good, though. I think they made a fantastic move designing it as a car for the masses rather than a car only a hippy could love.

Then again, Lutz said Global Warming "is a total crock of shit," so no wonder I'd like his cars.

RE: Even better
By Spuke on 6/6/2008 4:15:33 PM , Rating: 5
GM said the Volt would be $40k. And considering initial sales will be limited to 10k a year, expect said dealerships to markup up the car another $10k.

RE: Even better
By FITCamaro on 6/6/2008 7:26:09 PM , Rating: 2
If they can get it down to $30,000 under mass production, they'll have an instant success. Nothing can touch that thing in terms of looks and efficiency. It's an actually usable car. And it doesn't look like the droppings of a large animal either like the Prius.

RE: Even better
By Chernobyl68 on 6/6/2008 4:39:27 PM , Rating: 5
Ethanol is a low energy fuel. That's where the low fuel efficiency comes from. To produce the same power, more must be burned on each stroke. So, less miles per gallon.

RE: Even better
By Alexstarfire on 6/6/2008 4:44:18 PM , Rating: 2
True, but if they can burn the fuel more effectively then you could get the same power out of a lower energy fuel source. I mean, a gas engine is only 30% or so efficient, that means that 70% is just turned into heat of some sort. Even though E85 has like 1/3rd less energy it could certainly make up the difference. I'm not saying it will, because it probably won't, but it could.

RE: Even better
By FITCamaro on 6/6/2008 7:28:02 PM , Rating: 3
Also ethanol is a higher octane which allows a hotter combustion chamber. Which helps on emissions because more of the crap gets burned up.

RE: Even better
By HVAC on 6/10/2008 4:14:35 PM , Rating: 2
Ethanol is a higher "octane" which allows higher compression which means more of the fuel-air explosion power is transferred into mechanical energy.

Unfortunately, hotter combustion creates more emissions. Basically hotter means that more nitrogen is cracked and mated with oxygen to create NOx (oxides of nitrogen).

More optimal combustion occurs as a very quick, but lower temperature explosion. And that is the trick in matching compression to the fuel. You want enough compression to be efficient, but not too much to overtemp combustion.

RE: Even better
By Reflex on 6/6/2008 7:57:35 PM , Rating: 3
E85 has only 65-70% of the energy in a gallon that gasoline has. Its not a matter of 'designing an engine for E85' because that dosen't get around the basic problem, namely that the fuel simply does not have the same amount of energy as gasoline.

E85 is to gasoline as gasoline is to diesel, it has less energy per unit of measurement so regardless of how efficient you make the engine it will always have less mpg than an equivilent design running a higher energy content fuel.

RE: Even better
By sprockkets on 6/7/2008 1:43:52 PM , Rating: 2
Again, you are wrong. Ethanol has a higher octane rating, allowing for higher compression ratios for equivalent efficiency to a gasoline engine. The problem is, is that if you need an engine to run on either E85 OR gasoline, you cannot change the compression ratio on the fly to run either one best. SO, to offset the lower compression ratio with E85, you have to use more ethanol in the air/fuel mix.

If an E85 only engine ran gasoline, it would be destroyed due to premature detonation.

RE: Even better
By masher2 on 6/7/2008 1:46:56 PM , Rating: 2
While you are correct, the higher compression ratios achievable with E85 -- or even an all-ethanol fuel -- would still not come close to achieving the MPG from pure gasoline-only fuel. The difference in energy content is too large.

RE: Even better
By dschneider on 6/7/2008 4:42:55 PM , Rating: 5
I think I run on regular and my wife runs on E85.
Cause there is a lot of premature detonation.

RE: Even better
By nugundam93 on 6/9/2008 12:56:37 AM , Rating: 2
hahahahaha somebody give him a 6! that was one witty comment there.

"So, I think the same thing of the music industry. They can't say that they're losing money, you know what I'm saying. They just probably don't have the same surplus that they had." -- Wu-Tang Clan founder RZA

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