Fall 2013

Close to Home | Cleaner Cars for All Consumers

As federal fuel efficiency and global warming pollution standards continue to improve, cleaner cars and trucks are rolling onto showroom floors every day.

Conscientious consumers can choose from hybrid and electric vehicles as well as conventional gasoline-powered vehicles equipped with new technologies that reduce operating costs and global warming pollution. A few of these innovations are described below.

Putting the Brakes on Wasted Energy

Two technologies pioneered in hybrid and electric vehicles eliminate an idling engine’s emissions and waste of fuel: stop/start and regenerative braking. Stop/start technology, which shuts off the engine automatically when the vehicle is idling and uses a starter motor to seamlessly re-engage the engine when you lift your foot off the brake, improves fuel economy by about 5 percent. Combining this with regenerative braking, which uses small electric motors to capture the energy from braking that would otherwise be lost as heat and then uses that energy to help propel the car when you put your foot back on the gas, can improve fuel economy by an additional 4 to 8 percent. These technologies are also available as options or standard features on several conventional vehicles including the Buick Lacrosse, Buick Regal, Chevy Malibu, and Ford Fusion.

Where the Rubber Meets the Road

Keeping your tires properly inflated is one of the easiest (and most easily overlooked) tricks for maintaining optimal fuel economy. By reducing the amount of drag your engine must overcome to propel the vehicle, proper tire maintenance may improve your fuel economy by up to 2 percent. Nissan has made it even easier to keep the perfect amount of air in your tires with its tire monitoring system called Easy-Fill Tire Alert, which identifies tires with low pressure; as you fill the tire, the system blows the vehicle’s horn when the proper pressure is reached. Green Car Journal named Nissan’s system one of the top 10 green technologies of 2013.

High Tech under the Hood

Some of the most significant fuel efficiency improvements derive from technologies that are all but invisible to drivers: engine and transmission modifications that increase efficiency without sacrificing power or performance. For example, cylinder deactivation turns engine cylinders off when their power is not needed (as when cruising on a highway), boosting fuel economy by about 5 to 7 percent. Turbocharged direct injection can boost fuel economy another 14 to 25 percent by injecting fuel directly into the engine’s combustion chambers at high-pressure rather than through the intake manifold, enabling a smaller, more efficient engine with similar performance. Continuously variable transmission offers an essentially infinite number of gears, allowing the engine to operate near its optimal speed at all times; this improves fuel economy by 4 to 14 percent compared with a typical six-speed automatic transmission. These technologies are being used in various combinations by Ford, General Motors, Honda, Mazda, and others in vehicle classes ranging from compacts to pickup trucks.

By purchasing vehicles with these technologies, consumers create an incentive for automakers to offer even more fuel-efficient options in more vehicle classes. This is just one step we can take to cut our oil use in half over the next 20 years, and achieve a safer and more secure energy future in the process.

 

Also in this issue of Earthwise:

Dialogue


Engineered genes were recently discovered in wheat. Is that a problem?