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MIT engine boosts mileage by 30 percent

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by eagle33199, Oct 25, 2006.

  1. eagle33199

    eagle33199 Platinum Member

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    Researchers at MIT say they can boost mileage in cars by as much as 30 percent, depending on the car, by a carefully planned injection of ethanol in the cylinder.

    http://news.com.com/MIT+engine+boosts+mile...html?tag=cd.top

    In the article, they focus on the idea that mileage can be boosted without the use of a hybrid engine. However, i note a couple things from it that could be great for hybrids like the Prius - First, the engine they're using is half the size of a normal engine, which says to me that it's about the size of the Prius ICE. Second, it's a fairly cheap upgrade to the engine (only $1000 at manufacturing, supposedly). And finally, the boost - if it does increase mileage by 30%, why start by increasing low mileage cars? if you start with a hybrid, you get much more "bang for your buck" in the increase.

    It does raise a question about how much ethanol is needed for it to run as planned, and what happens if you run out of ethanol - hopefully it uses little ethanol (less than what's in E85), and if you run out, I'd hope you just get worse mileage, not that the engine won't work. Because we'd need ethanol only pumps first, which would probably take a while to pop up nation wide.
     
    #1 eagle33199, Oct 25, 2006
  2. pagoda113

    pagoda113 New Member

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    As an MIT grad yet non-engineer it is pleasing to see something come forth from the 'tute that might help reducxe our burden on nonrenewable energy. The article says very little abut the actual technology, however. I saw nothing yet about this in issues of Technology Review.

    Speaking strictly abut the fuel content: I had always thought that EtOH was less energy potent. Am I thinking about it all wrong?
     
    #2 pagoda113, Oct 26, 2006
  3. nerfer

    nerfer A young senior member

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    <div class='quotetop'>QUOTE(eagle33199 @ Oct 25 2006, 03:30 PM) [snapback]338212[/snapback]</div>
    Well, the skeptic would say it takes about 30% additional ethanol :p
    Actually though, it may not help the Prius engine that much. Part of the benefit of this design is it helps you boost the compression ratio, and the Prius ICE already has a pretty high compression ratio compared to most gas engines. Not sure if that's due to the Atkinson-cycle it uses or a different optimization, I'm not much of an engine engineer, or whatever they're called, and it's been awhile since I read that description. But who here wouldn't pay another $1000 for even 15% better mileage? Now that's an upgrade option worth letting consumers vote for with their wallet!
     
    #3 nerfer, Oct 26, 2006
  4. eagle33199

    eagle33199 Platinum Member

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    <div class='quotetop'>QUOTE(pagoda113 @ Oct 25 2006, 11:01 PM) [snapback]338409[/snapback]</div>
    yes, ethanol does have a lower energy potential, which is actually the point. Basically, a gas engine is tuned very specifically to be at just that right point in terms of compression ratio and gas/oxygen mix to get the most power without "knocking". knocking occurs when a piston fires when it's not supposed too - mostly due to a mixture thats too high or a compression ratio thats too high. What they seem to have done at MIT is to find a way/timing to inject ethanol into the chamber to sort of quench it and prevent knocking. Not sure on all the details, but this means they can get a bigger stroke from the engine and increase the mixture at the same time, both of which help to increase the power available.
     
    #4 eagle33199, Oct 26, 2006
  5. clett

    clett New Member

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    Not sure why this is news, they've been using ethanol to increase boost / compression ratio for years in motorsports.
     
    #5 clett, Oct 26, 2006
  6. qbee42

    qbee42 My other car is a boat

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    <div class='quotetop'>QUOTE(eagle33199 @ Oct 25 2006, 04:30 PM) [snapback]338212[/snapback]</div>
    You get a bigger bang for your buck with a low fuel mileage vehicle. Given the same miles driven, 30% savings at 18mpg is a lot more fuel savings than 30% savings at 50mpg.

    Tom
     
    #6 qbee42, Oct 26, 2006
  7. eagle33199

    eagle33199 Platinum Member

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    @ 18mpg, 30% savings increases you to 23.4mpg -> increase of 5.4mpg
    Over 100 miles, you save 1.28 gallons
    Over 10 gallons, you go an additional 54 miles

    @ 50mpg, 30% savings increases you to 65mpg -> increase of 15mpg
    Over 100 miles, you save 0.46 gallons
    Over 10 gallons, you go an additional 150 miles.

    So yes, you can think of it as saving more money by increasing a low mileage car, but at the same time, i think of it as increasing the distance traveled on the same amount of gas. in the first case, the non-hybrid would seem to do better, in the second the hybrid does better - it's all about how you look at it.
     
    #7 eagle33199, Oct 26, 2006
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