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These Engineering Tricks Are Helping Automakers Build Greener Cars

To satisfy the U.S. love of trucks while reducing emissions, automakers are taking some unusual approaches.
August 12, 2016

Americans love big cars, but big cars chew through gas at an alarming rate. And while hybrid and all-electric cars are making inroads in the market, they’re very expensive to produce. Meanwhile, automakers are using cheaper engineering techniques to bump up the efficiency of popular models.

In 2011, President Obama announced an agreement made between 13 car manufacturers to increase average fuel economy of cars built in 2025 to 54.5 miles per gallon. But sustained low fuel prices and increasing sales of trucks as opposed to cars are making that target look ambitious. A pair of recent government reports suggested that fuel economy might reach 50 miles per gallon at best.

One way to get there is to reduce the weight of vehicles. Traditionally that’s involved using aluminum, magnesium, or even carbon fiber. But as the New York Times reports, there’s an unlikely-sounding alternative: glue.

The 2017 GMC Acadia SUV makes use of an advanced adhesive, similar to that used by airplane manufacturers, to hold together its subframe. Unlike the usual rivets or spot welds, glue holds the entire seam of a join together, increasing stiffness. In turn, that allows the manufacturer to use thinner steel. Along with other weight-saving measures, that allowed the Acadia to shed 700 pounds.

Elsewhere, the electrical systems inside cars are being juiced up to help improve their green credentials. Most regular non-electric cars use electrical systems rated at 12 volts, but as The Economist points out, 48-volt systems look set to appear in cars starting in 2017. The increased voltage allows the vehicles to borrow some of the tricks used by hybrids without the large cost.

Audi’s forthcoming luxury SUV, the SQ7, for example, uses a 48-volt system to power a turbine that forces extra air into the engine to provide a momentary power bump. A prototype Ford Focus uses a similar power supply to provide torque assistance, which helps the car accelerate.

These kinds of advances may not have the dramatic emission-reducing power of switching to all-electric motors, or even hybrid systems like those found in the Toyota Prius. But they’re less of a departure from the norm for both manufacturers and consumers, and they could help cut emissions in vehicles that Americans are already buying in huge quantities.

Cars may increasingly be built by software developers, but electrical and mechanical engineers still have a big role to play in making our vehicles more efficient.  

(Read more: New York Times, The Economist, “Cheap Gas and Big Cars Are Killing Obama’s Fuel Economy Push,” “Automakers Shed the Pounds to Meet Fuel Efficiency Standards”)

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