Automobiles

TEN BILLION METRIC tons of carbon dioxide and other greenhouse gases are spewed into the atmosphere each year by the fossil fuel-hungry transportation sector. Over the typical 124,000-mile lifespan of an automobile, the Toyota Prius will emit 32 tons of carbon dioxide from its tailpipe versus a Ford Excursion spewing 134 tons.

The type of transportation employed has a major impact on the amount of carbon dioxide and pollutants produced. People can choose their mode of transportation and whether or not to be a part of a growing community that wants to reduce the effects of global warming by cutting back on tailpipe emissions. The internal combustion engine (ICE) is a poor choice of power source. It dissipates 80 percent of its energy as heat, even before it reaches the vehicle's rear axle. Two major approaches to reduce the threat of global warming have emerged in the automobile industry. The first approach encompasses both conservation and new technology. A proven idea is increasing vehicle efficiency at a greater rate than has been done to date. The automobile industry can also develop new vehicle technology beyond the gas-electric hybrids. Introduction of Pluggable Hybrid Electric Vehicles (PHEVs) that double the range of current hybrids and further reduce greenhouse gas tail emissions is on the horizon. Utility operators already know that they can handle the additional demand expected of the power grid, since most PHEV owners would plug in their cars at night to be recharged, when demand for 120-volt supplies is low. All that is needed is improved battery technology and the will of automakers.

A second strategy is to develop alternative fuel supplies to power vehicles. Ethanol-blended gasoline, such as E85, is appearing on the market. New American cars work with this fuel which is 85 percent gasoline and 15 percent ethanol. Vehicles manufacturer-certified to burn E85 produce less carbon dioxide is produced combusting this fuel than burning regular gasoline, in spite of the CO2 needed to produce the ethanol in the first place. Engine performance is boosted with E85, too, with some vehicles realizing a horsepower gain of up to 5 percent. One major advantage is lowered tailpipe emissions. Other mixtures are being developed, including the use of liquid hydrogen as an alternate source.

While many of these actions are voluntary, regulatory action is often required to raise mileage standards. In the United States, more stringent Corporate Average Fuel Standards (CAFE) spurs development of energy-efficient components and solutions for personal mobility. To achieve new goals for greater miles per gallon, and, hence, lower greenhouse gas emissions, more fuel-efficient engines and transmissions are needed for conventional gasoline-powered or diesel-powered vehicles.

BMW automobiles, a company that does not have a gas-electric hybrid on the market, is also contributing to better fuel efficiency. It developed a brake energy regeneration system as a result of an internal project to provide intelligent alternator control. Every car on the market uses an alternator to continuously generate power, regardless of the engine load. Known as “alternator drag,” the alternator consumes energy even when the car is cruising or accelerating, a process referred to as freewheeling. If the alternator only generates power during the braking cycle, the amount of fuel consumed overall is reduced. BMW expects its brake energy regeneration system to cut energy consumption by 3 percent on every car that adopts the technology. The conventional energy cycle can be deconstructed, [Page 104]analyzed, and subsequent innovations can deliver better miles per gallon for the driving public.

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