The composites industry has been working hard for many years on getting automotive manufacturers to embrace carbon composites with open arms. Composites like carbon fiber offer a lot of promise for automotive manufacturing. Yet they are also expensive. That leaves the composites industry in the position of having to convince car companies that the higher cost of carbon fiber is worth paying for.
All their efforts appear to finally be paying off. For example, there is suddenly a buzz within the automotive sector over using carbon composites to make certain engine parts. Connector rods are a good example. Already there are a small number of custom fabrication shops making aftermarket connector rods for a small, select number of engines.
The connector rod is a small piece of kit that connects the pistons to the engine’s crankshaft. It is the main mechanism by which energy is transferred from crankshaft to piston. It undergoes a tremendous amount of stress as it pushes the piston up and pulls it back down again. Moreover, all of this takes place inside the engine – where combustion is occurring with every stroke.
Lighter and Stronger
The first and most obvious benefit of carbon composites is their strength-to-weight ratio. An aluminum connector rod is six times the weight of a carbon composite rod while a steel connector rod is 10 times heavier. Carbon fiber is stronger than both metals as well.
Reducing weight while increasing strength is the holy grail of automotive manufacturing. Lighter cars use less fuel. Lighter engines increase performance by making the process of propelling the car forward more efficient. All the way around, lighter is better. Making an engine lighter without sacrificing strength truly does change the game.
Resistance to Heat
For the longest time, most parts of the internal combustion engine have been made with aluminum or steel simply because of the heat that combustion generates. You cannot have a material that will not hold up to thousands of degrees. It turns out that carbon composites do quite well.
Another benefit of carbon fiber is that it is not subject to the same kind of fatigue experienced by aluminum and steel parts under high heat and stress. That means the material is less likely to fail due to overheating. There is one caveat however: when carbon composites do fail, failure tends to be catastrophic. There will be no warning signs of impending failure. A rod will simply break and that will be it.
Manufacturing Cost
Carbon composite connector rods are a long way from becoming mainstream. Once again, cost is the issue. As Salt Lake City’s Rock West Composites explains, there isn’t yet a process in place whereby the parts could be mass-produced at a reasonable cost. That may change thanks to 3D printing.
In the composites industry, 3D printing is known as additive manufacturing. It is a process that involves combining continuous carbon fiber thread with an epoxy resin that cures in place. A 3D printer lays the combined material down, layer upon layer, to create the desired part.
As additive manufacturing matures, it is capable of doing a lot more at a lower cost. The thinking is that one day it will allow for mass production of things like carbon composite connector rods. Until then, the rods will be the stuff of niche fabricators selling high-performance parts to those who can afford them.
Carbon fiber offers a lot of promise to the automotive industry. Carbon composite connector rods are just one example. Next time you buy new car, ask how much carbon fiber is in it. You might be surprised.
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