Petroleum-electric hybrid vehicles combine the desirable properties of electric propulsion with the portability and convenient refueling of petroleum fuels. Most of the...
Hybrid CarsLast Updated on 2010-12-16 00:00:00
Petroleum-electric hybrid vehicles combine the desirable properties of electric propulsion with the portability and convenient refueling of petroleum fuels. Most of the locomotives and many of the ships built during the past 50 years are diesel-electric hybrids. In such vehicles, a large diesel engine turns a generator that recharges batteries, which in turn power small electric motors connected directly to the wheels or propellers. This arrangement operates the diesel engines under the uniform loads and low revolutions per minute that optimize their fuel efficiency. It also eliminates the need for complex transmission systems between an engine and several wheels or propellers. Finally, isolating the diesel engine’s vibrations from the frame of a locomotive or hull of a ship leads to much smoother and quieter operation.
Today’s hybrid cars take a different approach:... More »
Fuel Cell Cost and ReliabilityLast Updated on 2010-11-25 00:00:00
Fuel cells today require some very expensive components.  In particular, the electrode/catalyst and polymer electrolyte membrane are literally worth their weight in gold.
A catalyst is a substance that promotes a chemical reaction without itself being consumed. As such, it must remain chemically inert under the conditions necessary for the reaction. Nearly all electrode/catalysts for hydrogen fuel cells contain platinum, a chemically inert metal that costs over $35 per gram, substantially more than the price of gold. At present, a typical fuel cell vehicle (100 kilowatt = 134 horsepower) contains over $70,000 of platinum.  Much of the current research on fuel cells focuses on minimizing the platinum needed for efficient catalysis. For example, one approach uses nanotechnology to produce tiny particles of platinum alloy with higher reactivity. These developments may someday... More »
Electric VehiclesLast Updated on 2010-11-12 00:00:00
Vehicles powered by electric motors or by a combination of gasoline engines and electric motors are becoming more commonplace. Such vehicles are highly efficient in the slow, stop-and-go traffic of cities, but are less advantageous for high-speed, long-distance travel. Battery technology limits the amount of energy that a vehicle can carry and thus its speed, range, and recharge time. Lead-acid batteries are inexpensive and reliable but are heavy and have low energy and power per size and weight. One of the manufacturers of these vehicles is developing a model equipped with lithium polymer batteries that will extend its range to 100 miles (161 km), but pricing and availability have yet to be determined.
On the high end of the electric vehicle spectrum is a Tesla Roadster. For $101,500, one can purchase this electric-powered sports car that has a top speed of 125 mph, an... More »
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