By almost all accounts, the days of abundantly cheap gasoline are over. But we're not necessarily doomed to suffer fuel price fatigue into eternity. By 2025, it's quite possible that the average passenger automobile will be capable of getting more than 50 miles per gallon (21.3 kilometers per liter) — if it runs on conventional fuel at all.
Making it to that mark will come neither easily nor cheaply. Fortunately, the engineers and scientists tasked with the goal of making automobiles more efficient have a few tricks left up their collective sleeve.
One of the biggest areas available in which to make gains is in reducing the mass of cars and trucks — a broad discipline known as automotive lightweighting. Lightweighting seeks to shave pounds from the overall weight of a vehicle by using advanced materials, ingenious construction and novel systems. It's been estimated that every 10 percent of weight reduction yields a decrease of between 6 and 7 percent in fuel consumption. So even small weight savings — when multiplied by the thousands of parts on a typical vehicle — can up add to significant amounts.
This trend has actually been in progress for decades: The average sedan today weighs 3,000 pounds (1,361 kilograms), compared to 4,500 pounds (2,041 kilograms) 30 years ago. That's despite the steady growth in gizmos, safety features and creature comforts that have made our vehicles like rolling homes and offices over the years. Continuing to make vehicles lighter depends on taking smart approaches to making their component parts lighter.
In the next few pages, we'll cover five of the smartest innovations that will make, and in some cases are right now making auto parts lighter.
Among the heaviest parts of a car or truck are those that compose its "heart" — the engine. Items in the engine bay, such as the engine block, pistons, crankshaft and various accessories are made of high-strength, heat-resistant metals. They have to be, in order to withstand the tremendous stresses and temperatures created by the force of thousands of controlled explosions per minute that take place beneath the hood.
The trade-off for that durability is that traditional engines are extremely heavy — several hundred pounds in the case of a typical passenger automobile.
Once running, the engine has to transfer its rotational energy from the engine compartment to the wheels on at least two of the four corners of the car. To do this requires a transmission, drive axles and more parts that add weight and inefficiency.
Electric motors placed directly at the hub of an individual wheel eliminate the need for many of those bulky and maintenance-prone parts on a conventional car. These motors are then controlled by a computer that directs them to spin the wheels as needed. Michelin and car company Venturi made a big splash with this technology in 2010, showing off Michelin's Active Wheel System on the swoopy-looking Venturi Volage concept. Not only did it contain electric motors in the wheels, but also a powerful electric braking system and active suspension (also inside the wheel hub)!
In addition to the design of the parts themselves, it's quite important what they're made of. Head on over to the next page to read about the smart materials that are making car parts lighter.
In one of the most famous movie lines ever, "Mr. McGuire" (Walter Brooke) uttered what would become a classic bit of advice to "Benjamin" (a then-fresh-faced Dustin Hoffman) in the 1967 film "The Graduate:" "I just want to say one word to you ... plastics. There's a great future in plastics, will you think about it?"
Decades later, Mr. McGuire's counsel has proven not only prophetic, but also remarkably enduring. Plastic appears in some form on almost every item we buy, from the packaging to the object itself. Even today, researchers are looking into ways to make plastics more versatile, stronger and capable of withstanding more extreme conditions.
One company, Polimotor, has gone so far as to propose and build plastic engines, claiming a 30-percent weight savings over traditional all-metal engines.
In the near term however, you're still likely to see plastic in conventional places, just more of it.
In addition to interior parts such as trim, knobs, consoles and panels being made of plastic, it's also used for front and rear bumpers, side skirts and mirror housings.
It may not be too far off that you see everyday production vehicles whose entire exterior bodies are made of plastic, skipping the aluminum or steel typically used for body panels.
We could even find a good use for some of the estimated 2.5 million tons of plastic water bottles thrown away each year: The Hyundai QarmaQ concept, as an example, boasts a body made substantially out of recycled plastic water bottles. There's yet another "wonder material" poised to relieve some of the weight burden imposed by steel parts, while providing equal or better strength. Read all about it on the next page.
Carbon fiber is certainly no newcomer to the automotive scene. Bred from the aerospace industry, then used in auto-racing to make vehicles lighter on the track, this technology migrated its way to specialty uses on the performance aftermarket.
Among the performance "tuner" crowd, it's a badge of status to bolt on carbon fiber hoods, spoilers and even body panels with the pieces unpainted and carbon weave visible.
In a nutshell, carbon fiber consists of strands of carbon atoms formed into fibers that are then woven into an easy-to-mold cloth. When sheets are soaked in a special resin, applied to a mold or form and allowed to cure, the resulting product can be as strong as steel, but at half the weight (and 30 percent lighter than aluminum). It works very similarly to the way fiberglass does, but yields much higher strength.
So why don't we already see carbon fiber everywhere? Cost. The lengthy and complex cycle of making carbon fiber parts makes them many times more expensive to produce than similar ones made of steel or even lightweight metals that are pricier than steel.
For a long time, the fuel savings that car buyers would enjoy as a result of lighter carbon fiber parts would not financially justify the added expense from not using steel.
A number of car manufacturers, notably Lexus and BMW, are working to change that with intensive research into developing ways to reduce the cost of producing carbon fiber for vehicles. Lexus, for instance, has developed a remarkable three-dimensional, robotic loom capable of weaving not only flat sheets of carbon fiber, but also curved pieces already shaped to the contours of particular body parts.
How is a car builder supposed to "get the lead out," weight-wise, when vehicles rely on batteries (traditionally heavy lead acid ones) to supply a vehicle's many electrical needs? Up until a few years ago, lead-based batteries were the juice supplier of choice for electric cars — largely because that was all that was readily available.
Then along came nickel metal hydride (NiMH) batteries that were lighter and still capable of packing a powerful charge — and used widely in hybrid vehicles.
Automakers are placing their bets on hybrid and fully electric vehicles to help them meet government-mandated mileage requirements in the future. But even NiMH batteries lack the energy storage capacity to practically meet the expectations of consumers. It's because of a property called "energy density." For right now, batteries aren't able to hold the same energy "punch" for a given weight as fossil fuels.
Enter lithium ion batteries, which have a higher energy density than lead acid or nickel metal hydride. They've long powered cordless power tools and laptop computers, but have also suffered a nasty penchant for exploding when they got too hot. While somewhat rare, these catastrophic failures occurred often enough to prompt major concern, like when they would cause consumer laptops to catch fire. They also kept major automakers leery about putting them in mass-produced vehicles until the kinks could be worked out.
Still, companies like Tesla saw fit to put them into its fast, sleek Roadster electric sports car — which by all accounts delivered phenomenal performance.
And the time for lithium ion car batteries to go more mainstream is fast approaching. MIT researchers, for instance, found a way to slash re-charging times and make lithium ion batteries more stable (by using nickel rather than cobalt, along with the principal element lithium). This and other advancements make it appear that lightweight lithium will play a major role in helping autos keep the pounds off in the future.
Usually when people talk about an "electric vehicle," they're referring to the fact that it has an electric motor that turns the wheels. But there's another meaning for the phrase — it can also refer to cars that replace heavy and bulky mechanical linkages with lighter, smaller electric components. Commonly referred to as "drive-by-wire," or "x-by-wire," these electrical and electronic components can be used to more precisely control throttle response, steering and even braking.
This particular technology claims a lineage from fighter jets. Fly-by-wire received its baptism by fire, literally, when it was used as the sole control method for the F-16 Fighting Falcon, which debuted way back in 1978. Jokingly dubbed "the Electric Jet" at first by wary pilots, it eventually acquired the nickname "Viper," along with pilot respect, as it proved itself repeatedly in combat.
"By-wire" controls went on to be used in both military and commercial aircraft, and eventually the auto industry.
Since by-wire controls take up less space, that means auto designers can provide more creature comforts such as better leg- and head-room, and make fewer design compromises overall. And since they weigh less, by-wire systems let the vehicles they're installed on go faster, farther or both.
Not everyone is comfortable with the idea of going to fully electronic systems. What if, after all, they suffer from faulty programming, just like the software we use on our PCs sometimes does? The last thing you want is a computer glitch preventing you from applying the brakes when you really need them.
In actuality, mechanical systems wear out, break and experience other problems as well. As with many other automotive innovations, it could just be a matter of time before people accept the newer control technology as "normal," once it's been proven through increasingly wider use.
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