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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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Even better
By nvalhalla on 6/6/2008 3:20:09 PM , Rating: 2
I would think this would show even better results in hybrids. Recapturing electricity from braking provides power allowing for improved gas mileage, I'd think adding this constant charge to that would help even more. Maybe I'm giving this reclaimed energy too much credit, but if it is of a decent voltage, it should help quite a bit.

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.

Seems expensive
By FishTankX on 6/6/2008 3:18:09 PM , Rating: 2
Wouldn't it be easier to just have the turbo drive the alternator?

RE: Seems expensive
By MrBlastman on 6/6/2008 3:27:16 PM , Rating: 2
That would have a negative effect on the amount of compression the Turbo could achieve creating parasitic drain on the total power output of the engine.

In this case - I think it'd be far greater than the parasitic drain that an alernator hooked directly up to the pullies and belt system.

Or, look at it this way, no longer do you have to wait until 2500 RPM's for your Turbo to spool up and enter boost, but now you have to wait for 5000 RPM's.

That'd suck. Royally.

RE: Seems expensive
By mmatis on 6/6/2008 5:10:58 PM , Rating: 2
Isn't that what turbochargers are supposed to do? I mean after all, superchargers blow...

RE: Seems expensive
By stryfe on 6/6/2008 5:56:48 PM , Rating: 2
Not at all. They both "blow" if you want to put it that way. They both pressurize the engine's intake charge, they just use different methods to do so. A supercharger is belt driven while a turbo charger uses the kinetic energy of the exhaust to drive it.

RE: Seems expensive
By Rugar on 6/6/2008 3:27:17 PM , Rating: 5
Any mechanically driven generator, however it is attached to the engine, will decrease the power available to deliver to the drive train. By using a thermoelectric generator like this, it takes power that is currently lost to waste and recaptures it as electricity. If it can be constructed so that it recovers even a tiny percentage of lost power, it should result in dramatic fuel savings over the lifespan of an automobile.

By therealnickdanger on 6/6/2008 3:20:15 PM , Rating: 2
When I first read the title, I thought to myself, wow, DT doesn't know what a turbo is? I'm glad that was not the case. 5-10% improvement sounds great if it doesn't add anything to the cost of the car.

RE: Turbo
By Spuke on 6/6/2008 4:16:55 PM , Rating: 2
I'm glad that was not the case. 5-10% improvement sounds great if it doesn't add anything to the cost of the car.
"There's no such thing as a free lunch." Of course, it will add to the total cost of the car. The real question is, how much?

RE: Turbo
By Chernobyl68 on 6/6/2008 4:42:05 PM , Rating: 2
I could see this as an add on to the catylitic converter, or in series after it. They usually require a certain temperature range to work effectively.

RE: Turbo
By therealnickdanger on 6/6/2008 7:17:31 PM , Rating: 2
That was kind of my point... :P

RE: Turbo
By AlmostExAMD on 6/6/2008 11:42:13 PM , Rating: 2
Agree, I was almost laughing until I realised what they are trying to achieve, Thought it was just another fancy name for a turbo kit. lol
I just hope that it can be implemented in such a way that there is no ludicrous weight added to the car and also cost.
5-10% doesn't sound much but that is quite substantial considering that an internal combustion engine is roughly 25-30%(Don't quote me,Not up to date on engine efficiency) The other 70% is wasted.
Looking forward to seeing this making it to general public.

RE: Turbo
By wallijonn on 6/10/2008 9:57:27 AM , Rating: 2
Thought it was just another fancy name for a turbo kit.

Instead of thinking exhaust gases driving blades, which would directly replace the alternator, think of wires around a nail, as heat is applied to the nail electricity is generated. I tend to think of it as wires around the exhaust pipe, or a long nail inside the exhaust pipe with wires around it. The 500 degree exhaust at the catalytic converter end will cause electricity to be formed. The wires could then go from inside the catalytic converter to outside the rest of the exhaust pipe.

You'd have one end of the battery terminal at the catalytic end and the other end from the end of the tailpipe.

What's this have to do with the price of tea?
By rsmech on 6/6/2008 5:18:51 PM , Rating: 2
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.

This is irrelevant information. This power is only usable by the car. If there is extra power it goes to nothing else. This is marketing at it's best & it has invaded science. The real statistic they should have used is how much gas it saves. Or is this irrelevant fact more flashy?

I'm all for conservation but don't mislead me. If it's a good thing & the right thing to do you don't need to sensationalize it with misleading info.

By Alexstarfire on 6/6/2008 7:06:52 PM , Rating: 2
True, to an extent. It would mean that the batteries would probably last a bit longer, at the very least, and could potentially increase your mileage by reducing the workload of the engine, if only a little bit. It's not as great as they make it sound, but that's like saying the energy doesn't count at all.

By lemonadesoda on 6/6/2008 7:20:27 PM , Rating: 2
I agree that the electriciyty is somewhat "useless", UNLESS, it can be put to good use. Here are some very obvious suggestions:

1./ Remove alternator. This takes power from the car, and therefore the car would get a better BHP or would save fuel per km.

2./ Use the electricity for seat heating and/or airconditioning. Both of these use up significant power... taken from the engine, converted to electricity by the alternator. Notice how small engined cars noticably lose power when turning on a/c AND mpg goes down? This would make a big difference

3./ Hybrid cars. Get even better efficiency out of the "hydrocarbon" component of the engine.

By rsmech on 6/7/2008 1:30:21 AM , Rating: 2
This is what I mean. I know it can make the car more efficient, but that is it. So tell us about MPG savings because of it not total power that can be generated, it's irrelevant.

By brandonicus on 6/7/2008 8:53:39 PM , Rating: 2
I agree.

When reading that part I immediately thought "hmmm am I supposed to be impressed by collective terawatts." The article was fine; but the last paragraph seemed silly to me.

However, I love the overall idea considering gas is slightly over $4.00 where I am.

Water Injection
By Natfly on 6/6/2008 3:56:11 PM , Rating: 2
Another method of increasing combustion engine efficiency using the massive amount of heat generated is through water injection

Spraying water into the pistons cools the air/fuel down allowing leaner fuel ratios as well as extra power from the expanding water vapor.

I don't know if it is feasible or what possible hangups there are.

RE: Water Injection
By Smartless on 6/6/2008 4:35:38 PM , Rating: 2
Thanks for the link. Learn something new everyday. I've heard of various ways to run leaner on a mixture though I'd think that all of these methods will lead to smaller engines in general. Modifying a car's intake system will have a similar result which increase the power produced by a smaller displacement engine. Never know, we may end up with 0.7L turbo-water-cooled-hybrid-Methanol-fueled SUVs. haha. Sorry just cracking myself up.

RE: Water Injection
By cubeless on 6/6/2008 10:06:44 PM , Rating: 2
the problem is that water injection is it's another thing that must be carried by the car and maintained by the driver...

Have I been reading these postings correctly?
By Lerianis on 6/8/2008 1:15:13 PM , Rating: 2
Only 30% of the energy from fuel in a regular gas engine actually is used? That seems EXTREMELY wasteful to me.... no wonder we have such low gas mileage in the United States compared to the rest of the world.

Someone needs to fix that, and the automobile makers have to be given incentives to fix this problem, which is the tragic flaw of our oil-based system.

By djc208 on 6/9/2008 8:30:14 AM , Rating: 2
What!? Did you forget the sarcasm flags?

US engine technology is equivalent to any other place in the world. We're not "behind" anyone as far as gas engine efficiency. We tend to use less diesel since our fuel tax structure and emmissions regulations are not designed to support small diesel applications like Europe, but the 30% number (which is optomistic and BEFORE driveline losses) is not specific to the US.

This is just the nature of the beast, converting chemical (potential) energy into mechanical (kinetic) energy in any application is just not very efficient by its nature. Even the highly glorified fuel cell is around 50% efficient last I heard, and that does chemical to electrical conversion, which then requires a secondary electical to mechanical via the electric motors (which are pretty efficient).

More wishfull thinking than pratical today
By tygrus on 6/9/2008 9:11:16 AM , Rating: 2
Thermoelectric (TE) method is not efficient in itself and slows down movement of heat ie. tail pipe and exhast gas would be hotter than pipe in free air. Requires you to cool down the cold side to maintain a temperature difference. Current semi-conductor TE cann't handle the high temperatures or high temperature differentials (also heat transfer bypasing electric circuit so large temperature diff does less than you think).
The requirement for wieght of heatsinks, water cooling and not good for short trips (engine needs to be warmed up).
The old method pf heat conversion to work is the production of high pressure steam to do the work which is still low efficiency, bulky and limited. At least the tail pipe would be cooler (safer). You don't want to use/waste extra water.

By HVAC on 6/10/2008 4:20:19 PM , Rating: 2
How about a Stirling engine?

Too early?
By djc208 on 6/9/2008 8:17:27 AM , Rating: 2
Seems to me this is still a "someday it might happen" article. Not sure what made it so newsworthy compared to all the other such ideas.

There are lots of industrial applications where this could be used that are not as picky as the automobile market. Think about all the companies that use large ovens and heaters, not to mention commercial power plants. Once you have a product they're interested in then I'd work on shopping the auto industry.

Seems to me that right now it's just a concept probably with some rough prototypes. When they have a version that powerplants and facilities want to use, places where the size and weight are not a concern, then they can start thinking about automotive applications, which will require additional refinement and modification vs an industrial application.

Stirling Engine
By Hare on 6/11/2008 5:04:31 PM , Rating: 2
Stirling Engines have been used for this purpose.

Here's a link, interesting stuff

Potato meet exhaust pipe...
By edpsx on 6/6/08, Rating: -1
RE: Potato meet exhaust pipe...
By baadcatj on 6/6/2008 4:58:37 PM , Rating: 3
edpsx - you are not understanding the technology here. This is not IN the exhaust flow but rather build into/around the exhaust pipe (similar to the water jacket/flow inside the engine itself not being in the combustion chamber/cylinder). So, it doesn't block the exhaust and cannot create an increased back pressure.

This technology absorbs the heat that is just being radiated off and then because of the differential between the heat it has absorbed and the temperature of the surrounding area, it can create an electrical charge which can then be stored in a battery (and then used to power the vehicles electronics or to power the electric motor(s) of the hybrid vehicle).

Obviously, this will cost quite a bit to bring to the consumer market - what new technology doesn't - but it would have a large impact if all vehicles became hybrids that would not need as much combustible fuel because it could reclaim heat to produce it's own electricity, thereby increasing the range battery power range.

(Touching on the relatively obvious, this will not be able to create electricity when there combustion engine is not running, as there will not be enough heat produced to create the gradient with which to create a new electrical charge for battery storage. So, while this may sound a little bit like a 'perpetual motion vehicle', in reality it will only enhance the distance and decrease the need for fossil fuels and battery charging by utilizing generated heat before dissipating it, increasing the efficiency on an individual vehicle).

Whew - that was long!

RE: Potato meet exhaust pipe...
By Ratinator on 6/6/2008 7:19:42 PM , Rating: 2
So if this were to go around the exhaust pipe and the amount of energy created is relative to the difference in temperature between its surroundings and the exhaust pipe, would this not effectively work better in colder climates?

By JonnyDough on 6/9/2008 8:02:46 AM , Rating: 2
I wonder too about the heat in cars. Why is it that we don't have rear-engine cars in the south where they don't need the engine heat rising back through the car,
and front engine cars in the north where they need to pull heat off the engine to warm the car? That way when you run the AC or the heat, you don't need as much.

Why can't some sort of sealed steam contraption be placed over the motor, like a sealed and pressurized radiator that is used to generate energy from the heat? It would apply the same concept used in cooling pipe heat sinks on computers. The liquid boils, rises to the top where it's cooled, and then drops back down to be boiled again. It's a pretty simple concept.

We already lug the water around in our cars and heat it. We already use air to cool the water. Now why not let naturally rising steam do some work to make electricity to power the car? If you ran sealed pipes up from the engine along the top of the car and then down the back and return it to the front, wouldn't that be an effective cooling loop? Just write "Caution, Hot" on the pipe.

If this sounds unsafe because of a crash, I'm sure engineers would come up with a safe way of doing it. At the VERY least they could do this on semi-trucks somehow. Those things burn a ton of fuel. If we took all the trucks off the road suddenly, gas prices would plummet. And yes, I'm aware they burn diesel. Diesel is just less refined gasoline!

RE: Potato meet exhaust pipe...
By masher2 on 6/7/2008 1:51:13 PM , Rating: 2
> "So, it doesn't block the exhaust and cannot create an increased back pressure."

Yes, but remember the function of that exhaust is to allow heat to exit, not just hot air. Even without any additional backpressure, a wrapper around the exhaust pipe (or even the engine itself) will have a minor insulating effect, and will thus reduce engine efficiency somewhat.

I have no doubt the overall effect will be very small, possibly even negligible, but it most definitely exists.

RE: Potato meet exhaust pipe...
By MisterChristopher on 6/8/2008 5:17:12 AM , Rating: 2
Masher, your comment does not make sense. The point of a unit like this would be to collect energy in the form of heat and convert it to electrical energy. Therefor instead of insulating, you may actually find that if used in conjunction with an effective heatsincing system, this could potentially convert more heat to electrical energy than energy you might naturally dissapate via radiant heat off your muffler system.

Basically think of these things as a reverse peltier. They could potentially be attached to other radient heat surfaces like the engine block, the radiator, the hood of the car, or any other part of your car where there is a temperature differential between two surfaces because of air flow or coolant channeling. Effective car designs could easily channel air over certain areas.

The amount of current created is based solely on the difference in temperature. This means that when there is only a small difference in temperature between the two surfaces of the peltier, there will only be a small current. But, with well designed heat transfer systems, I can see a potential for creating several zones on the car which make hotspots for this for of energy harvesting. These areas should be able to generate very decent current. Definitely enough to completely replace your alternator, or enough to charge batteries in hybrids very effectively.

RE: Potato meet exhaust pipe...
By masher2 on 6/8/2008 5:26:05 PM , Rating: 2
> "Therefor instead of insulating, you may actually find that if used in conjunction with an effective heatsincing system, this could potentially convert more heat to electrical energy "

Converting heat energy to another form is more difficult than simply exhausting heat -- all else being equal, any system which attempts to capture the energy of exhausted heat is going to radiate slower than one which does not.

Now while its feasible that this might be outweighed by an "effective heatsinking system", you're then not comparing apples to apples. One could easily put such a heatsink on just the radiator itself, without adding the thermoconverter itself.

RE: Potato meet exhaust pipe...
By MisterChristopher on 6/9/2008 4:01:11 PM , Rating: 2
I'm not comparing apples to apples. I am trying to show a way that this technology could easily equal or surpass the heat dissapation qualities of our current muffler systems. This technology is totoally plausible without creating any additional heat load or insulating effect compared to what we have now. It could possibly even reduce the average heat level dependant on your design and the temperature differentials that design creates.

This technology is excellent. You could go get a peltier right now and start using it to generate electricity without any complicated heatsincing and no insulating. Just get one and strap it onto your muffler. See what kind of current it produces. I bet if you had a few of these thermoelectric units attached to your car, you could power an HHO creation process via waste energy.

RE: Potato meet exhaust pipe...
By masher2 on 6/9/2008 4:32:51 PM , Rating: 2
> "Just get one and strap it onto your muffler. See what kind of current it produces"

You're still missing the point. Sure it'll produce current...but it'll also the heat level inside the muffler itself.

A single peltier won't raise it measureably...but it also won't create much current either. Cover the entire muffler surface with them, however, and you'll see not only a higher internal muffler temperature, but a slightly lower fuel efficiency as well.

The laws of thermodynamics are quite rigid. If you want to cool a system, you're going to have to input energy. You can't achieve a cooling effect simply by processing waste heat.

RE: Potato meet exhaust pipe...
By bldckstark on 6/6/2008 5:00:33 PM , Rating: 2
They won't be putting anything IN the pipe. The will take the heat from the interior surface of the pipe, and contrast it with the coolant. This will cause the magneto-electric material in the TEG to flow from the cold surface to the hot surface in one big circle. As it flows it will pass through some highly scientific device that will extract free electrons from the movement, like an alternator does with copper windings and a magnet. There isn't likely to be any increased backpressure.

People have been trying to find a way to use the heat in exhaust pipes for a good use for many decades. It looks like somebody is finally getting there. Cost will be the final decider.

RE: Potato meet exhaust pipe...
By V3ctorPT on 6/6/2008 6:05:25 PM , Rating: 2
I wonder how much energy can Snoop Dog create... hum...

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