• Apr 17th 2011 at 8:25AM
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After analyzing 26 individual components in compact vehicles, the University of Aachen and the European Aluminium Association concluded that using aluminum in some automotive parts (illustrated by the graphic above) could safely reduce vehicle body weight by up to 40 percent, resulting in 2.7 more miles per gallon of gasoline burned or approximately a 10 percent reduction in overall fuel consumption.

The study claims that the weight reduction potential of high-strength steel is limited to a mere 11 percent because nearly 40 percent of the 26 parts analyzed could not be made any thinner without severely compromising the vehicle's structural integrity. However, it was found that aluminum could be used to slash weight without reducing the vehicle's stiffness or hampering its performance. The Aluminum Association's Transportation Group says that this study, combined with other data, suggests that approximately 525 pounds of weight savings could be realized by using aluminum.

Click here (pdf) for a look at European Aluminum Association's 58-page report, titled "Stiffness Relevance and Strength Relevance in Crash of Car Body Components."

[Source: Green Car Congress, Aluminum in Transportation (pdf)]

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    • 1 Second Ago
      • 4 Years Ago
      Best examples of aluminum cars thus far?

      I'd say:

      1. Original Honda Insight
      2. Audi A2

      Two cars that were ahead of their time -- check resale values on either of these with the "new reality" gas prices.
        • 8 Months Ago

        The only way your 8 paragraphs have any relevance is if you believe gas prices are going back down --and relatively soon (history repeats)..

        If that's your angle, why even read ABG? Just keep driving whatever your driving, ignore fuel prices, and encourage others to do the same -- nothing to worry about, all systems normal.

        • 8 Months Ago

        Look, I didn't create these demographics! These are inherent dynamics concerning marketing vehicles in the US. You can pretend they don't exist, and during an energy crisis they will temporarily abate, but once the crisis passes, they will come back to bite.

        Why do you assume I think oil prices will decline? Exactly where did I say that? Did you bother to read paragraph four?

        In fact, I believe that the age of oil is ending, but this won't change peoples basic desires, they will simply look for an alternative energy source for transport to replace what exists today. I really hope it becomes electric, or I have lost a fairly substantial investment! Sure, Automakers can build small, light, aero-dynamic vehicles, but only a very few will willingly purchase, and even fewer will actually enjoy such a vehicle.

        In turn, why do you believe that EV energy storage capacity will remain the same as it is currently? I believe that the EV industry will rapidly develop energy storage to compete with fossil fuels. Then, once again, light weight construction will be only a marginal issue. I already own a lightweight production EV, (and have for nearly five years). It's a good little car. Seats four in modest comfort, and has a range of about 60-90 miles depending on how it's driven. But, I far prefer my LEVRR, all the weight of a luxury SUV, but still 300+ klms range with all conveniences. The major difference is price. Leaf's sales would be negligible if the Lexus CT 200 was a full PIEV, and sold at the same price! In fact the majority of buyers would flock back to larger EV vehicles if energy storage was increased.

        What on earth is so hard to understand? Replacing the fuel supply in private transport, doesn't require a redesign of people and society, no matter how much you would like to cast everyone in your own image! It's just new technology, not a religion!
        • 8 Months Ago

        • 8 Months Ago
        Both of these cars were produced due to unusual circumstances. In the case of Audi, the special relationship with Alcoa made the application profitable, and even then Audi only uses aluminium for two models. Honda was the first company to make a completely monocoque aluminium car in the NSX.

        Although, in performance cars, and vehicles with very low fuel consumption, an emphasis on lightweight materials is important, in 'regular' volume vehicle design more expensive materials are a disadvantage.

        The concept of lightening a vehicle by 400 lbs, may be a big deal in a lightweight concept car, it means very little in a 6000 lbs luxury SUV. (everyone can lighten the load, just lose two adult passengers) . The point is that although the car industry may from time to time find lightweight construction to be good PR, in reality it's always been cheaper to simply tweak a little more performance. Fuel consumption, except for the very anorak, is difficult to measure in day to day driving, and as a result, fuel economy has more to do with perception than reality for the average driver.

        The advent of the EV has re-ignited the issue of lightweight materials, due to the limited capacity of an EV's energy storage capacity. This will be reasonably short-lived, and as the energy storage capacity technology improves, the Leaf buyer will start to demand creature comforts at a lower price.

        The US is a fairly unique automotive marketing environment. Automobiles marketed in the US must contend with a combination of factors. The US has traditionally enjoyed the cheapest gasoline in the industrialised world. A large land area with highway's interconnecting US cities, and vast sprawling suburbs, serviced solely by automobiles. Relatively cheap automobiles. (although not of the highest standard) Low driving age. Prosperous population. Physically larger automobile buyers. etc..

        All these factors have produced a US car industry, that was unassailable in it's home market until the oil crisis of 1974, since then subsequent oil crisis have eroded US car makers in favour of imports. But the moment the US market feels confidant of affordable fuel, the rush is on to buy an SUV type vehicle.

        Steel is a more economical product to build this sort of large vehicle. Lightweight construction for volume vehicles is fairly pointless, when the list of extras a modern auto must be equipped with to compete successfully in the marketplace, is so extensive and heavy.

        The challenge is to make the energy storage capacity larger, and the vehicle more powerful. It's a simple marketing issue. What's easier, tell the client to lose weight, or provide a bigger chair? The former may be more honest and morally beneficial, but is unlikely to generate more sales!
        • 8 Months Ago
        The Insight is uninteresting, given that a CRX HF with the same number of seats weighed in at 1700 lbs - 10% less.
      • 8 Months Ago
      If aluminum is so much more expensive than steel, why does soda come in disposable aluminum cans and not steel cans.
        • 8 Months Ago
        I remember when cans use to be made of steel.

        It is interesting that even though cars are being made from lighter materials they are still gaining weight. I find it strange that my huge Cadillac weights less than many of the smaller cars of today.
        • 8 Months Ago
        Aluminum doesn't rust when you fill it with acid water.
      • 4 Years Ago
      While it's true that aluminum would reduce the weight of a car, you have to consider the enormous amounts of energy it takes to produce aluminum.
        • 8 Months Ago
        Aluminum production requires a tremendous amount of electricity. Don't get me wrong, I endorse using it as a way of reducing vehicle mass, but taking into consideration the energy used to produce it is certainly relevant.

        This paper claims 13kWh per kilo.


        This one says 15.7kWh per kilo.

        • 8 Months Ago
        @2 Wheeled Menace

        The wiki article is a good resource. The main reason is because direct reduction from the bauxite ore with carbon is not possible unlike with iron. The intermediate product. aluminum oxide. has an extremely high melting point, and so requires electrolysis to convert to aluminum, which is why it is so energy intensive.

        This one goes into more detail:
        • 8 Months Ago
        Thanks Jake! very informative.. you get a star, lol
        • 8 Months Ago
        Aluminum has a lower melting point than steel.

        What's the extra energy use of aluminum involve? extraction and processing?
        • 8 Months Ago
        Enormous amount of energy perhaps, that is regained/captured by recycling, and in Europe, at least in Germany I am given to understand, the car company has to recycle its own product.

        Carbon composites, on the other hand, also reduce weight, can be reused, but cannot be reformed into new product, and then there is the expense.

        In America, I know that the steel in a car is reliably melted down for new product. I suspect that high strength steel will be more common path, especially as you don't have to worry about having to protect against electrolytic wasting of the steel when it is in contact with aluminium.

        Of course a smaller car would also do it, we shall see how many give up their SUV.
      • 4 Years Ago
      Cans were made of steel before
      • 4 Years Ago
      There is a long history of automotive components being made from Aluminium. Often this is for lightness or the extra ease in hand-shaping car bodies and casting other components, in low volume numbers. In the UK and other countries, aluminium was often used when steel was unavailable.

      Economically, automakers always return to steel for cost savings and superior strength.

      It's an old argument, but the following text book observations still have validity:

      Aluminium's Formability is approximately 2/3 that of steel (less forming range). This is a very important advantage for steel for vehicle styling and overall manufacturing robustness.
      Advantage: Steel

      Aluminium's hardness is lower than steel's. Stone chips and surface quality are harder to maintain for an aluminium body over a vehicle's life cycle.
      Advantage: Steel

      Noise, Vibration, and Harshness (NVH). The ability of any material to attenuate airborne noise is directly proportional to its mass. Regarding airborne noise, steel clearly has an advantage in most cases.
      Advantage: Steel

      Steel is magnetic, aluminium is not; very important in recycling end of life vehicles. Steel is easily recycled because of its magnetic properties versus other nonferrous materials such as lead, copper, zinc, and aluminium. Thus, Steel separates extremely efficiently, but the nonferrous scrap will possess all the unwanted residual materials as well (polymers, glass, adhesive, ceramics, etc.).
      Advantage: Steel

      Galvanic potential
      Aluminium's galvanic potential is high, while steel's is low. On an auto body, when aluminium and steel are in direct contact, accelerated corrosion is evident. There are barrier technologies available to help with this condition when mixing metals, but at a significant cost impact.
      Advantage: Steel

      Lastly, PJ's observation as to the immense amount of energy it takes to make steel, is a very compelling argument against the widespread use of Automotive Aluminium on enviro-grounds!
        • 8 Months Ago

        When these new 'truths' emerge, I'll acknowledge them, in the meantime I'll try to stick with what'd true now.


        Yep, aircraft from steel.......around about the same time as Ocean Liners are made from aluminium!
        • 8 Months Ago

        Thank you for the source. I didn't accredit the information to any source because I was unaware of the USSC site. I was quoting from a more obscure source, who in turn cited this information, unattributed, as a text book quote.

        Nevertheless, the information still has validity. It may be compiled by USSC, but is not refuted. The cost pricing differential may not be as great as 1998, but aluminium is still uneconomic in large scale automotive use, although alloys are becoming more sophisticated.
        • 8 Months Ago
        ...... or so says the United States Steel Corporation.


        (always a good idea to reference your source)
        • 8 Months Ago

        "It may be compiled by USSC, but is not refuted."


        Come on.

        It's all refutable.

        For one, Galvanic Potential:

        How is that "advantage steel"??? It's only "advantage steel" if you think the whole thing should be made out of steel. Just like it would be "advantage aluminium" if you thought the whole thing should be aluminum.

        Different metals/materials have different strengths and weaknesses. Steel has never been an irrefutable material choice. And as we move into an era of higher energy costs the new "truths" will evolve.
        • 8 Months Ago
        I guess they should start making aircraft out of steel....
      • 8 Months Ago
      Improved aerodynamics could save a lot more than 10%. Like 25-50%, or more.

      Weight causes you to use more energy to accelerate, for sure, but you then can use some of it in better coasting -- kinetic energy can be used, to some extent. If you downshift, while braking, the fuel gets shut off.

      Aerodynamic drag though, is a total loss. There is no way to regain any of it back.

        • 8 Months Ago
        And that is why cars are getting bigger and heavier for safety, but also getting a lot slicker: Aerodynamics are free.
      • 4 Years Ago
      Really! You mean aluminum is lighter than steel? Now that's news!
        • 8 Months Ago
        I don't know if this is trusthworthy:


        Well it's not related direcly to cars but I think still applies. So 3x lighter but for same stiffness it wouldn't be. For selected components this does make sense though.

        Audi says they got the weight reductions for the new A6/A8 by using more alumium (and they used that for last several decades). I'm sure it's more costly though. You just apply it to certain components. 40% might be a stretch unless it's an R8.
        • 8 Months Ago
        Audi people will pay for performance, and light can be fast.
      • 4 Years Ago
      I have heard (but cannot find any reference) that the big 2.5 auto manufacturers are bound through union contracts to make their products from a certain percentage of steel.

      Does anyone know if this is true or false?
        • 8 Months Ago
        I have a Saturn with plastic body panels,and they still look great 16 years later...

        I would love to see more fiberglass body panels or truck beds, aluminum or carbon fiber hoods, and good plastic parts (not screws...GM).

        I doubt that the Union has any agreements, but I wouldn't put it past the steel industry to give bonuses to certain people if they use XX amount. There has to be some reason Saturn became "Just Another Car Company" instead of "A Different Car Company".
        • 8 Months Ago
        I've no idea if it's true or false, but all the major manufacturers (American, Japanese, European, Korean) seem to use similar amount of steel. The major exceptions being Saturn and Audi. If there is such a deal, it goes beyond the 2.5.

        I suspect there's at least as good a chance the decision is economic rather than contractual.
        • 8 Months Ago
        @Carcus, I have no idea, but it would seem very dubious conspiracy type theory.. It also wouldn't explain why every other volume automaker in the world uses steel.
      • 4 Years Ago
      Covetic aluminum is the answer - unfortunately the DoD has got their hands on it and they don't want it in the hands of the common folk.
        • 8 Months Ago
        what's your source on that claim?
        my guess is industry is just stagnant as usual. DOD isn't preventing the use of carbon and glass either. carmakers just don't use it. nor think about it
      • 4 Years Ago
      as for the article, of course it is trivially true that you can make a car lighter with high strength alu instead of soft steel. it's why it's used for ladders and commercial jets..
      of course fiber composite can be even better. if you don't mess it up like mclaren did and bmw with the i8. both around 1400kg which is pathetic.
      • 4 Years Ago
      so, the "European Aluminium Association" partnered with a university to help with some research (read "advertising")

      I am not saying they are incorrect - really I have no idea but all of us should practice critical reading. The source of this 'research' indicates a supremely high likelihood of bias.
        • 8 Months Ago
        wincros, just like with steel, you can make aluminum strong or weak. Really depends on the formulation of the alloy.

        In my electric bike building adventures, i found many aluminum bikes to be of varying quality. I have seen some cheaper 'Giant' frames literally twist and dent when dropped or impacted.. on the other hand i have seen some of the better Trek frames hold up better than steel.

        My 90's Hondas had the thinnest steel body panels ever. They would dimple if you looked at them. It's all about the thickness and quality of the material.

        There is crappy steel out there too. A lot of it comes from China. That's how you end up with a 25lb chromoly steel bike and a 40lb China steel bike..
        • 8 Months Ago
        That "crappy" Chinese steel is only what was spec'd, because someone with purchasing power decided low cost trumped light weight.

        The big difference with the Chinese is that, when you want something at a rock bottom price, they are willing to find a way to meet that price, where other manufacturers might say that it can't cut thing to get the price that far down.

        Also, Giant is *Taiwanese*, not Chinese. Like most Taiwanese OEMs, it's Taiwanese design and Chinese / Vietnamese manufacturing to spec.

        I guarantee this:

        If you work directly with the Chinese bicycle manufacturing companines on a Trek-sized order paying full Trek-equivalent manufacturing prices, you can get a Trek-beating result with Trek-beating specs.
        • 8 Months Ago
        @John H

        You are absolutely correct! You can build a car from exotic combinations of materials to decrease the weight, but at what cost? Vehicle design is about producing a profitable set of dynamics that is easy to build in volume and has mass appeal. Design, engineering, Technology, all vie with image, comfort, safety, fuel consumption, and marketability. Getting the right combination, for the era, is the secret of a successful volume model.

        Cutting of a few dollars in fuel, is pointless if the purchase cost becomes unjustifiable!
        • 8 Months Ago
        It is typical in providing charts and graphs that do not necessarily go to their conclusions. There is no standard car. For instance Honda Civic with an aluminum block engine that already weighs well south of 3000 pounds is not what they are talking about when they tout 40 percent weight loss and 10 percent fuel consumption improvements. A 1500 pound 175 inch long car? I don't think so. They may be talking about a Cadillac or Lincoln SUV or they just may be pulling it out of the air.

        As for its suitability I did see an aluminum Ford Racing car on display in a dealership years ago the bodywork of which had been ruined by people leaning on it. Shallow dents all over it.
        • 8 Months Ago
        I'm pretty sure they're correct, but whenever I see a big cut in weight (500+ lbs) and big jump in economy (+10%), I wonder what the price increase is. Nothing is for free.
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