MIT has breakthrough in ethenol car, 50 mpg

[Alientank]

So make 200 HP with 50MPG? The formula they're using is:
- start with a 1 Liter 4 cylinder engine (very fuel effecient, lacks power normally)
- bump engine compression to 20:1
- turbo boost for more fuel economy (4PSI saves gas, 8PSI waists gas)
- supress knock at high engine loads with ethenol injection

That all equals 30% better fuel economy on most cars, without paying the typical $4000+ Hybrib costs/fees.


Better than Hybrids
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A proposed engine design approaches the efficiency of gas-electric hybrids, but could be far cheaper.

Consumers hoping to cut gasoline spending, with average gas prices nearing $3 a gallon, could opt for hybrids. But even with gas prices high, the added cost of hybrid cars can cancel money saved at the pump, suggesting the need for lower-cost alternatives.

A new type of ethanol-boosted, turbocharged gasoline engine could be the answer. The engine would be almost as efficient as gas-electric hybrids, but cost much less, according to its MIT inventors -- Leslie Bromberg and Daniel Cohn, plasma science and fusion center researchers, and John Heywood, professor of mechanical engineering.

The new engine would improve efficiency in two ways. The first is to decrease the size of the engine, which reduces friction, thus saving fuel at light engine loads, such as during city driving. When more power is needed, a turbocharger kicks in. It uses exhaust flow to compress air, making it possible to combust more air and fuel in a smaller space.

The second approach is to engineer the engine to have a higher compression ratio -- the ratio of the volume of air and fuel before and after it is compressed in an engine. A higher compression ratio "makes the engine more efficient, because you expand the burned gases more and extract more energy out of them," Heywood says.

Neither of these are new ideas. But in the past, such efforts have been limited by a phenomenon called knock: high compression ratios and extreme turbocharging cause gasoline to spontaneously combust when the engine is under heavy loads, such as during acceleration or at high speeds, potentially causing serious damage. The MIT researchers have found a way to prevent knock, allowing them to crank up the turbocharger and increase the compression ratio -- and thereby increase the power of an engine by 250 percent.

If this increase in power is taken advantage of to reduce the size of the engine -- which would go against long-time trends emphasizing performance over fuel economy -- it could save gas. "This allows very large pressure turbocharging, very large downsizing of the engine, and makes it possible to have a small engine with much higher efficiency," Cohn says.

The researchers solved the knocking problem by injecting into combustion chambers precisely controlled amounts of ethanol at moments when the engine is working hard enough to cause knock. Compared with gasoline, ethanol has higher octane, a rating of how much a fuel can be compressed before it combusts spontaneously, that is, before it causes knocking. The injected ethanol also cools the mixture, so it effectively increases the octane rating of the fuel mix to about 130 -- as good as high-performance racing fuels, Cohn says.

The system would use relatively little ethanol, about 1 gallon per 20 gallons of gasoline, so Cohn estimates the separate ethanol tank would have to be refilled about as often as an oil change. Furthermore, since it would require relatively minor modifications to existing technologies, Cohn says the design could be in production vehicles as soon as 2011 -- with the help of a recent collaboration between their startup, Ethanol Boosting Systems (EBS), Cambridge, MA, and Ford Motor Company, Dearborn, MI.

The MIT researchers estimate their engine would add only $500-1000 to the cost of a vehicle, which includes the added costs of the high-end turbocharger, a direct-injection system, and a stronger, smaller engine. This modest premium compares favorably to that of hybrid cars. According to a review in Consumer Reports (April 2006), some hybrid vehicles failed to pay for themselves over the course of five years, even when factoring in federal tax credits and gas prices that rise to $4 a gallon. In contrast, Cohn says, their engine would pay for itself in two to three years.*

This modest premium compares favorably to that of hybrid cars. According to a review in Consumer Reports (April 2006), some hybrid vehicles failed to pay for themselves over the course of five years, even when factoring in federal tax credits and gas prices that rise to $4 a gallon. In contrast, Cohn says, their engine would pay for itself in two to three years.

The new engine should be 30 percent more efficient than conventional engines, based on a computer model the researchers say accurately reproduces the behavior of internal-combustion gasoline engines. In comparison, a Toyota Prius gets about 30-35 percent better fuel economy than a comparable vehicle, according to tests by Consumer Reports. In the same review, the magazine showed a $5,700 price premium for the Toyota Prius over a conventional vehicle.

Rodney Tabaczynski, former director of powertrain research at Ford (who is not involved with EBS), says the ethanol "will definitely help the octane problem" and existing electronic controls and feedback systems should make the controlled injection feasible.

The challenges EBS is likely to encounter he says, have more to do with logistics -- two fuel tanks in a vehicle can be hard to implement, and there's the challenge of making sure ethanol is available at the corner gas station. Also, the engine will need a system that ensures it isn't damaged if the driver forgets to fill the ethanol tank.

Tabaczynski also cautions that real fuel savings will depend on an individual's driving habits. As with hybrids, cars with these engines will get their best mileage when driven in a city, not at 70-75 miles per hour on the highway with the throttle wide open.

Sounds pretty interesting to me.

[NEODARK]

So now, we'll have people stating:

My 2 litter bottle of MT.Dew is TWICE as big as your engine capacity

[gamefoo21]

I wonder if they bothered to mention that cranking the compression ratio way up also makes an engine spit out alot more pollution...

Another thing... A 3 banger is actually more efficient than a 4 banger... Just like a V6 is more efficient than a V8...

Its also going to be a stop and go car with very lil oompf on the highway.

But then again what do most MIT geeks really know about cars besides the ricers they drive and the super cars they drool over...

[Jasef]

SAAB is working on some ethanol/electric motor. That will be fairly interesting.

[JonZ]

wasn't that more expensive to produce than regular gaz?

[Braham]

Originally Posted by JonZ

wasn't that more expensive to produce than regular gaz?

Any country in the world who can grow crops can become part of the fuel market, whereas certain localized oil deposits mean only a few countries control the world's entire fuel needs.

Cost is not eveything. The political/human benefits waaay outweigh the cost issues.

I would be willing to pay more for a fuel when I knew the price was dependent on measureable things, like farm crops etc. And would be stable over time.

[ScottDoom]

That sounds sexy. I'll take one of those engines put into the body of a Karmann Ghia.