Reducing car weight is more difficult than it looks. Lighter materials of the same strength are usually more costly. Brake disks are an example where several lighter materials exist, but each currently comes with negatives. Cost for some, limited max temperatures for others. Downsizing is possible and is currently being done, but many buyers stubbornly insist on being able to carry a family in comfort. The best approach seems to be a holistic approach, which is well underway. This, too, is costly, requiring a coordinated design, development, and manufacturing effort with technical support from suppliers. Those efforts are some of the reasons that car weight is not dramatically falling. But progress, though slow, is continuing and new cars now weigh considerably less than some of their forebearers.
grand, I'm aware of the fact that this stuff doesn't run as hot as steel, but wanted to make sure you knew it was a composite. The main benefit the research is aimed at here is reducing weight, not size. I'm not surprised to hear that aluminum can be a problem in race cars. The vehicles this material targets are consumer cars and military transport vehicles.
Ann, I understand that this is Aluminum Composite but that doesn't change the aluminum part very much. This company's own website http://www.relinc.net/Attachments/MotorcycleBrake.pdf states that the brakes can NOT run as hot as a steel rotor.
Materials Primer - Melting Points:
2024 Aluminum - 502C
4130 Steel - 1432C
6Al4V Titanium - 1604C
Obviously we don't run these things right up to the melting point, but this gives us a clear view of how much heat we can dissipate from a material. If I can run a material 3 times hotter, I can make it 3 times smaller.
grand, thanks for your comments. This is not aluminum but an aluminum composite. That fact, plus the fact that the composite includes ceramic, makes me wonder whether one of the reasons for the ceramic is to lower heat, especially since the company developing the material has experience making similar composites for NASA for extreme temperature apps, as they describe here
I've used aluminum rotors on a race car. I won't ever do it again. The coefficient of thermal expansion is much greater than steel. This means that the rotor heats up and grows, diminishing the clearance between the rotor and caliper until the rotor actually grinds against the caliper (I know, I know... you can always design it with more clearance to compensate. But it is not a drop in replacement at that point). Secondly, Aluminum gets really weak as it gets hot and will fall apart under high mechanical and thermal load. This is exactly what happened to me (lots of little melted aluminum chunks all over the track and my car). Steel, titanium and Carbon can glow red hot and still function as a brake rotor, Aluminum can not.
I knew a brake job was due a while back and did a little searching as to what race cars use. I knew they would completely fry a steel rotor and formula 1 would melt it. Unfortunatly these seem to be custom built. The only thing I think might be keeping them out of non racing cars is that they don't stop that all that well when braking from low speeds.
Re: Heat Vs. Stoppability Charles Murray2/16/2012 8:38:22 PM
If the automakers aren't taking a hard look at this, I'd be shocked. Cutting 30 lbs from the weight of a mid-size sedan is a gigantic change. Engineers typically fight to cut a pound or two from their vehicles. If they can cut 10 lbs, they're heroic. Thirty is off the scales.
----------- Sadly this same way of thinking is why they went bankrupt.
------------ We have cost effective composite tech that can drop most car, SUV's weight by 50% and double their mileage. And they know it as they all have built them as showcars like the GM UltraLite. And yet they drool over a few pound savings. Not much critical thinking there.
Does anyone know why Carbon brakes are not getting cheaper? After all carbon isn't that expensive a feedstock. How are they made?
They would be much lighter than even this advance with the lower weight advantages in handling and mileage.
Some brakes come with retracting clip springs that pull the pads off the rotor. In every EV I do I always check the brakes and many other drags like diff fluids, new low rolling resitance tires, aero mods, etc which can literally increase range 10-50%!! Or cut the battery pack/cost/weight as much for the same range.
Of course the best brake is one that doesn't have to stop all that excess weight most cars have by designing in lightness, KIS.
If the automakers aren't taking a hard look at this, I'd be shocked. Cutting 30 lbs from the weight of a mid-size sedan is a gigantic change. Engineers typically fight to cut a pound or two from their vehicles. If they can cut 10 lbs, they're heroic. Thirty is off the scales.
A new battery design, which replaces lithium with abundant and low-cost elemental sulfur, is still in its nascent stages but shows real promise for giving batteries more energy potential.
PTC will offer a virtual desktop environment for its Creo product design applications, potentially freeing engineers to run them from remote desktops on a variety of operating systems and mobile devices.
The push to achieving more intelligent, integrated manufacturing is putting a strong focus on networking and connectivity as key enabling technologies.
Now that solar and wind harvesting technologies are a thriving market, researchers are seeking other environmentally related energy sources for which they can create harvesting devices.
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For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This radio show will show what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.
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