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MIT researchers work on a ethanol direct injection engine

MIT researchers are developing an automotive power plant that promises up to 30% greater fuel economy than traditional gasoline engines. The new engine, which would be powered by ethanol, would be production ready within five years.

MIT says that it can boost fuel efficiency by directly injecting ethanol into the cylinder. Direct injection technology is already being used on a number of gasoline engine vehicles including the Mazda MazdaSpeed3, Lexus IS350 and Pontiac Solstice GXP. Direct injection allows for a finer control of fuel and injection timings compared to traditional fuel injected vehicles.

Knocking sounds, which are caused by spontaneous combustion, would be eliminated allowing ethanol engines to use heavily-boosted turbocharging systems and much higher compression ratios. The use of direct injection combined with ethanol is what allows for the 30% increase in fuel economy. MIT goes so far as to say that if every vehicle in the United States were equipped with such an engine, yearly automotive fuel consumption would drop from 140 billion gallons to 110 billion gallons.

"To actually affect oil consumption, we need to have people want to buy our engine, so our work also emphasizes keeping down the added cost and minimizing any inconvenience to the driver," said Daniel Cohn, of MIT's Plasma Science and Fusion Center.

MIT researchers believe that an ethanol-based direct injection engine would add just $1,000 to the cost of a new vehicle instead of the $3,000 to $5,000 seen with hybrids. What's more amazing is that the engine will be half the size of conventional gasoline engines. But while all of this sounds nice, the new technology will be for naught if more ethanol pumping stations aren't added to our existing fuel delivery infrastructure.



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By Beenthere on 10/27/2006 12:56:54 PM , Rating: -1
Ethanol, especially E85 will NOT allow you to run substantially higher compression ratios over premium gasoline. In addition it takes at least 27% more ethanol to power a vehicle with E85 over normal petroleum gasoline, i.e. ethanol delivers much low fuel economy. And ethanol will sell for $3.00 or more per gallon. An engine running on 100% ethanol will require about 40% MORE fuel than a gasoline powered vehicle to travel the same distance.

VW and Mitsubishi were the first to use direct injection gasoline engines on any commercial scale. There's about a 5%-7% real world improvement in fuel economy with DI gas engines when everything is optimized for DI. Ethanol isn't gonna improve the situation by more than a percent or two at best even if you could bump the compression significantly, which you can't. You also need to look at the pumping losses that occur with comp ratios above 12:1. The anti-knock value of ethanol isn't going to allow much higher compression ratios over gasoline engines so that 30% MIT claimed increased fuel economy figure is a fantasy based on my 30 plus years of engine design and development.

For those who don't already know... the U.S. ethanol program is a scam. Some very large farm interest get your tax dollars in very large quantities to grow corn for ethanol. If every farmer in America grew only corn for ethanol, you still couldn't supply 20% of the crude oil consumed by the U.S. And when you learn that ethanol powered vehicles get lower fuel economy the situation becomes fruitless. In addition it actually takes 1.2 gallons on crude oil to produce 1 gal. of ethanol using current technology. Yeah, I'm all for reducing our dependence on crude oil but ethanol is simply not the answer despite the hype of late. It's just another bureaucratic scam pork project.






By sdedward on 10/27/2006 1:23:30 PM , Rating: 1
I have been discussing/arguing on this topic with friends and family for the last year and I agree with many in saying that ethanol is not the answer. For the short term I think that diesel hybrids will be the answer.

1. We already have a distribution system set up for diesel. Yes this will involve upgrading and improving current distribution methods but it will not require the entire system to be rebuilt.

2. Diesel engines natively have a lower compression ratio and less moving parts. Diesel engines on average last longer and need less maintenance than their gasoline counterparts.

3. European diesel cars currently get ~40-50 mpg (not sure on these numbers) and adding hybrid technology would possibly increase this to near the holy grail of fuel efficiency, 100 mpg.

The setbacks are that diesel has a stigma of being dirty and loud, diesel vehicles drive a bit differently that gasoline vehicles, and supprt for diesel is being drowned out by politicians that want to continue to subsidize their constituents by promoting ethanol.


By Jeff7181 on 10/27/2006 3:06:50 PM , Rating: 3
1. Diesel fuel is oil based so it's NOT a viable alternative to gasoline in that respect. Whether we produce diesel fuel or gasoline with that oil doesn't matter, we still need that oil for both of them.

2. Diesel engines have a much HIGHER compression ratio anywhere from 15:1 to 25:1 whereas a typical gasoline engine is around 8 or 9:1. Diesels also don't necessarily have less moving parts, just different moving parts.

One of the great things about diesel is it's air/fuel ratio. At idle it can be close to 100:1 where a gasonline engine needs to be at 14.7:1 almost all the time.


By FITCamaro on 10/28/2006 2:58:40 PM , Rating: 2
Yup on number 2. Why you think turbo diesel trucks make so much power with simple tuning. Those blocks and bottom ends are already built to handle a ton of compression, so turning up the boost doesn't make much of an impact on anything but horsepower and torque. Some of the turbo diesel trucks out there can easily go from 600 lb ft of torque to 1000 lb ft with a simple computer tuner and get better gas mileage doing it. The only thing you have to really worry about is exhaust temperatures or you could start melting things.

I'd say the typical compression ratio for a gas engine these days is 9.5:1 - 10:1. The only engines that will have as low as a 8:1 compression ration would be a supercharged or turbocharged engine. Even 9:1 is getting rarer except in boosted applications. Higher performance engines typically have 10.5:1 - 11:1 compression ratios.


By GoatMonkey on 10/27/2006 3:20:46 PM , Rating: 2
Diesel has its advantages. That Audi race car is a torque monster that is pretty much kicking ass.

The problem with diesel is that it does not have quite as clear of an upgrade path. I mean if you are out in some little town that doesn't have a diesel gas pump you're pretty screwed, but if your car runs E85 it probably also runs fine on gasoline too, and you'll have no problem filling up.



By TomZ on 10/27/2006 4:15:28 PM , Rating: 2
In the U.S., there are no availability issues at all for diesel. There are enough vehicles in the fleet, both cars and trucks, that diesel is easy to come by.

The main advantage that diesel had in times passed was that it used to cost quite a bit less per gallon than gasoline. But refiners, distributors, and retailers have erased that price advantage entirely. So I see little benefit to diesel personally.


By rushfan2006 on 10/27/2006 4:28:21 PM , Rating: 2
Your other points aside, but the availability one isn't entirely correct. This isn't my opinion either - its FACT.

There are plenty of stations I pass by even here in Jersey that don't offer diesel, not many mind you - but some....However when I take the once every 4 year trip to Ohio from here...there are many many stations that don't offer diesel along my six hour drive.


By rushfan2006 on 10/27/2006 4:31:00 PM , Rating: 2
Btw if you wonder how I'd remember that...well because the last Ohio trip we took my brother in law's "dualy pickup" and that is diesel, and yes we ran out of fuel. ;)


By Kherberos on 10/27/2006 5:28:13 PM , Rating: 2
Well, I live in Europe and my car is doing +1000 km with 55 l of diesel, I belive this must be around 45 mpg. So a 6 hours trip is not really a problm, with that kind of mielage you can drive 10 hours without filling up the tank :-) (ok this true only if you do 70-80 mph on average)

Now, because of the high compression ratio, a diesel engine is theoreticaly able to "burn" almost anything, from alcool to any kind of vegetable oil (colza, tournesol,...)
So if you can t find a station with a diesel pump, just go to the local Wallmart and buy a few gallons of deep frying oil :-)


By Madellga on 10/28/2006 2:15:56 AM , Rating: 2
Don't do that, you are going to damage your engine and other components like filters, which were not made to handly different oils.

It might work for a while, but it will clog your engine.
And don't fill in alcohol......


By Lonyo on 10/27/2006 5:11:34 PM , Rating: 2
Greater fuel efficiency isn't a benefit?


By TomZ on 10/27/2006 9:24:19 PM , Rating: 2
Depends on the cost of diesel relative to gasoline, now doesn't it?


By semo on 10/28/2006 8:34:58 PM , Rating: 2
the difference in cost between gasoline and diesel isn't significant wherever you are (it's a little cheaper in some parts of the world, more expensive in others).

diesel engines are more efficient than gasoline engines.

a 1.9tdi audi a6 (chipped for 170bhp) with 3500lbs curb weight can get 50mpg easy.

diesel powered engines also have more torque than gasoline equivalents.


By semo on 10/28/2006 11:57:26 AM , Rating: 2
the main advantages of diesel (when used in a diesel engine) are
1: better mpg than a similarly sized gasoline engine
2: better torque than a similarly sized gasoline engine

not that it used to cost less in a particular part of the world.

audi were close to making the 100mpg car. too bad no one bought it and no new model was made
http://en.wikipedia.org/wiki/Audi_A2


By sieistganzfett on 10/27/2006 10:29:57 PM , Rating: 2
lol. thank you for saving me all the time to write that! i think MIT should say we should all resort to using horses for transportation to get away from needing the oil. ;)


By TheOtherBubka on 10/28/2006 1:19:31 AM , Rating: 3
I think it is safe to say that our fuel consumption/dependence problem is a very complex problem that is being approached in many fragmented ways - which leads to not much collective progress in any time frame.

To me, the ethanol vs oil vs hydrogen debate is really about we have a transportation fuel problem with no clear cut answer at this time. But, how did we end up with a problem?

1. Despite what is sometimes claimed, DOT numbers show CAFE worked. Despite increasing miles traveled per year by at least 10% from 1970 to 1995, fuel consmption for autos and motorcycles dropped from 760 to 530 gallons per year per vehicle. We are now back up to more than 610 gallons per year per vehicle when SUVs and minivans are figured in.

2. What most don't realize is that from '84-2000, on an inflation adjusted basis, the average person with an average per capita income driving an average car the average number of miles for that model year, their total spent on fuel has been about 5% of their income. Whereas in 1975, the average person spent ~8.5% of their income on fuel. < 5% is less than what alot of people pay in sales tax on purchases.

3. Why haven't local, state, and the federal gov't cared that our fuel consumption kept going the other way since 1986? The thought is they all collect taxes based uopn the # of gallons sold. Easy way to have more revenue for road projects without ever raising taxes. And what politician wants to run saying they are going to raise the gasoline tax? Okay..so how big are these revenues? Try $509M for ALA, $419M for ARK, ~$414M for CT, and $3.3B for CA. All are in FY01-02 and include gasoline and diesel tax revenue. Oh yeah, on July 1, 2002 the > 16 yr old population of ARK was only estimated to be 2.1M thus about $199.50 per registered driver in taxes.
Something had to help spread the cost to build roads to suburbia.

4. The amount of wasted fuel per year continues to increase. The Texas Transportation Institute (one of the more respected when it comes to traffice studies) estimates that about 5.7B gallons of gasoline were wasted due to traffic congestion in 2000. 2000 estimate total consumption of 73.1B gallons. Thus almost 8% of total.

Mitigating factor. We were able to 'double' our nations fuel economy from '65 to '75 because the annual volume of new cars into the market was a substantial fraction of the total number of registered vehicles. In today's US, with over 250 M registered vehicles and the annual US auto market selling about 16-17 M new vehicles per year, if every new vehicle coming off the line had twice the fuel efficiency of the vechile it was replacing, you are looking at over 15 years to replace the fleet neglecting vehicles lost to accidents.

General Thoughts (??????)
5. Congress needs to implement a new CAFE. It seems most companies won't really address the 'problem' unless they know how high they have to jump and what the penalties are for not 'clearing the bar.'

6. We always pay. No matter which way the subsidy or tax break is going. Whether corn or oil. Tax breaks for efficient engine development and hybrids. Disposal of contaminated materials. Not planting. Whatever. The US consumer foots the bill. It's a zero sum game. Whether local, state, or federal gov't or business, those costs are worked into the price either ahead of time or in times of 'high demand', 'market instabilities', 'unsettled political relationships around the world', 'capacity constraints', 'weather related phenomena', ....

Big ships take a long time to turn around.


By Slaimus on 10/30/2006 12:49:02 AM , Rating: 2
Corn-based ethanol is fairly wasteful indeed, but cellulase-produced ethanol based on raw plant materials looks promising. Ethanol engines are being developed because the future outlook for a more efficient way to produce ethanol it is fairly bright. Brazil's sugar cane ethanol is successful since they can produce it readily.


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