• Apr 28th 2010 at 3:56PM
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Carbon fiber has been a big success in the automotive aftermarket for years now. From interior trim pieces to strut bars on down to spoilers, the material is extremely popular and for many reasons. First, it's lightweight yet very strong. Second, it just plain looks good. And finally, it begs for attention from other car enthusiasts. While the aftermarket has been hot for this stuff for some time now, original equipment manufacturers (OEMs) have not exactly warmed up to widespread use of the space-age material in large measure because of the cost and complexity associated with its production. BMW has plans to change that beginning with the upcoming Megacity electric vehicle scheduled for release in 2013, and the company sees even more applications ahead.

In an electric vehicle, use of carbon fiber can make sense. Its lightweight characteristics help to offset the bulk of the on-board batteries. As BMW global sales head Ian Robertson explained:
By using carbon fiber, which is a little more expensive but 30 percent lighter, you don't need as many batteries for the same range. There's a trade-off that actually works.
Beyond the electric vehicle, where does carbon fiber fit in? Well it's really quite simple. Carbon fiber reduces weight and has excellent crash safety characteristics so it could feasibly be used in any vehicle to help increase fuel efficiency while maintaining high safety standards. As Robertson added:
We will be the first manufacturer to take carbon fiber to effectively high volume. We are developing a lot of volume technology here.

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    • 1 Second Ago
      • 5 Years Ago
      Widespread use of carbon fiber and word that BMW is bring back a 4 banger is all good news IMO, cant wait to see the end results and hopefully it will make other's in the industry follow suit. It will also be cool to see how BMW makes carbon fiber on a wide scale as it has always been seen as to labour intensive, but being bmw they probaly have some sort of trick up their sleeves.
        • 5 Years Ago
        +1 for both points.

        I'd like to see the return of the BMW 4 banger too....... before electric/alt fuel cars take over and gas cars look like antiques hopefully.
      • 5 Years Ago
      30% lighter? try 65.

      and it's all too little too late. 2013 for their first half assed attempt? take a look at the last 5 years of crude oil price. we'll be in big doodoo well before then.

      fiber glass gentlemen. fiber glass. now
        • 5 Years Ago
        it's probably futile to talk to you since the truth is not the issue, you are just set on me being wrong. mindless, irrational. but what is a good person to do. damned if I do and damned if I don't. you really should try a different attitude. in your mindless haste to defeat me, you only dig yourself deeper.

        my intuition is, and no doubt I am correct, I always am :) that the simple minded consideration that lower young's modulus will translate to lower stiffness in a structure by weight is only really true in a flat construction. once you have a span, a shell of some of volume, be it the outer shape of the car or more locally through the use of spacing core material, you very quickly move the stiffness considerations from young's modulus to tensile strength and in the tensile strength glass and carbon are quite similar. you can think golf club shaft (very narrow) vs a triangle or tetrahedron structure (spanned). spanning out the twisting forces means even the slightest deformation will lead rapidly to tensile/compression strength limits. it's true that carbon will still be stiffer but it could be 1mm deflection in a car sized glass fiber object vs 0.2mm of carbon. and some deflection is no doubt desirable. an infinitely stiff structure will shatter very easily if shocked even with 10 times carbon's tensile strength.

        as for deformation being associated with energy loss that is only true if the material is lossy in deformation. that is not a given. a material can be springy without energy consumption. I believe I've even seen glass fiber used as high performance suspension spring.
        • 5 Years Ago
        o ye of little faith.
        is carbon superior in price as well? in health concerns? in availability? in shock absorption? fiber glass has been used in ballistics protection because it has immense strength and can absorb impact. I'm not aware of any use of carbon for that.

        and as far as weight reduction goes I use the GM ultralite concept car as evidence that the entire car can become 65% lighter. not just the compositie.

        not that you have any understanding in the matter. you just mindlessly lean on bmw's statement
        • 5 Years Ago
        Really, Dan, it's futile talking to you. You blabber on and on without ever providing decent backup for anything you say. While everybody else often do. The only backup you ever provide is "My intuition says I'm right. So I must be. Which means your wrong." This also has the side effect of making you sound like a complete douchebag. Congrats.

        Like Jason said, simply switching to carbon fiber will only net you a weight savings of around 30% over aluminum, and thats only on the components you switch.

        And how can you use a concept car as backup with a straight face? Yes, they made a lightweight car. Sweet. Was it fully engineered? Of course not. Its a concept. It probably made the rounds through the wind tunnel, but I highly doubt it has all the required safety equipment and reinforcement. And it certainly doesn't have whats needed to pass current regulations, seeing as it was made in 1992.
        • 5 Years Ago
        Dear Dan:

        You're an idiot.

        1.) Find me some density numbers that say carbon is 65% lighter than Aluminum, which is obviously what they're comparing it to. (Hint hint -- You won't.)

        2.) Carbon is in every way superior to fiberglass. Clearly BMW isn't too concerned with cost for their applications, so there's no reason for them to use fiberglass over carbon.
        • 5 Years Ago
        Once again, you're not looking for impact absorption when designing an automobile chassis, you're looking for stiffness. For non-critical body panels, flexibility might be good, but not for structural chassis components. Carbon has 4 times the stiffness/weight ratio of S-glass, so a comparably stiff fiberglass structure would be 4 times as heavy as a carbon one.

        In addition to providing increased suspension compliance, an overly flexible chassis would provide a significant reduction in fuel economy compared to a stiff one, as any flex in chassis material would cause increased friction within the structure, and thus, energy loss.
      • 5 Years Ago
      Dear Dan:

      You're an idiot.

      1.) Find me some density numbers that say carbon is 65% lighter than Aluminum, which is obviously what they're comparing it to. (Hint hint -- You won't.)

      2.) Carbon is in every way superior to fiberglass (barring cost). Clearly BMW isn't too concerned with cost for their applications, so there's no reason for them to use fiberglass over carbon.
      • 5 Years Ago
      I have carbon fiber in my skid plates on my dirt bikes, when it does break it creates sharp, jagged, pointy edges. Curious to know how they get around this in a crash?

      You go BMW! 100 million dollar plant for producing CF right here in the Northwest for EV's. Excellent!
        • 5 Years Ago
        Don't put on the inside of the car.
        • 5 Years Ago
        That's not a property of the fiber though, it depends on the matrix (the polymer that holds the fibers together).

        Many of today's CF parts use thermosetting resins as the matrix which can be somewhat brittle, but are cheaper for low-volume production such as motorcycles or exotic sports cars.
        One of the challenges of making CF parts affordable for the mainstream is using thermoplastics instead which tend to have better mechanical properties, but require a lot of investment in machinery and process tech development.
      • 5 Years Ago
      "Second, it just plain looks goods."

      Does it really look good? I like it for it's functionality, but I'm not particularly a fan of the tweed jacket look.
      • 5 Years Ago
      Carbon Fiber burns, or at least most resin formulas used with it. Add spilled gasoline in a collision and you've got an instant bonfire that burns really hot. I seem to remember some Indy 500 driver saying he'd never drive another carbon fiber car specifically for that reason.
        • 5 Years Ago
        Basalt fiber is often used in fireproof clothing etc, is nearly as strong as carbon fiber and much cheaper:
        ' Basalt continuous fibers are produced from basalt rock using single component raw material by drawing and winding fibers from the melt. Once the continuous basalt fibers have been produced, they are converted into a suitable form for particular application. Basalt fibers show higher tensile strength and modulus, better chemical resistance, extended operating temperature range, better environmental friendliness than regular E glass - all in one material - getting close to and sometime outperforming carbon fibre and high strength glass and other specialty fibers but beating them price wise. Basalt continuous fibers are ideally suited for demanding applications requiring high temperatures, chemical resistance, durability, mechanical strength and low water absorption. Basalt fibre's technical features as below:

        1. Permanent flame retardant resistance: Limiting oxygen index (Loi) >70
        2. Extraordinary high softening temperature (point): >1200 Celsius degree
        3. Operating temperature range: from -260 to 760 Celsius degree
        4. High tensile strength (breaking strength): 3200 MPa
        5. Low elongation at break: 3.1 %
        6. High elastic modulus: 89 GPa
        7. Density: 2.7 gram/cubic centimetre
        8. Low thermal conductivity: 0.035 W/m稫
        9. High sound absorption coefficient: 0.95
        10. Low moisture absorption: 0.1 %
        11. High specific volume resistance: 1x1012 ohm穖
        12. radiation proof lead equivalent: 0.0073 mmPb'


        And present car parts including insulation:
        • 5 Years Ago
        Not a lot of gasoline in an electric car to leak out...
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