There are three types of experimental vehicle (EVs) propulsion technologies onthe currently being tested. Batteries are currently the most popular powersource for modern EVs but they are by no means the only available technology. Anumber of alternatives are under development and they, too, are well positionedto rival batteries as an effective EV power source.
1. Fuel cells Some of themost recent and exciting news in electric-vehicle development has centeredaround a new power source, called the fuel cell. The fuel cell utilizes aspecial membrane to generate electricity through the controlled reaction betweenhydrogen and oxygen atoms. Unlike batteries, which store electricityrather than generate it, fuel cells actually produce electricity through acontrolled chemical reaction between hydrogen and oxygen. Inside a fuel cell,the two elements are fed to opposite sides of a porous membrane. As hydrogenatoms pass through the pores, they are stripped of their electrons.
This resultsin a negative charge on the membrane’s hydrogen side and a positive charge onthe oxygen side. Stacking fuel cells in series produces enough power to operatea vehicle. Unfortunately, there is a downside to this innovativesystem?hydrogen is extremely volatile. It is also difficult to store andunavailable at local filling stations. Chrysler Corporation is currently workingon a fuel cell that eliminates some of these obstacles, notably storage andinconvenience. Their efforts may make fuel cells a viable option in the nearfuture.
One of Chrysler’s plans is to use small amounts of gasoline in fuelcells. Doing so would eliminate the dangerous proposition of storing hydrogenonboard an EV before converting it to electricity. A series of reaction chambersin the system would convert the gasoline to hydrogen as needed, and carbonmonoxide?produced as a byproduct?would be processed in additional chambersthat would convert it to harmless carbon dioxide. 2. Flywheels Another departurefrom chemical-based battery technology is the flywheel.
All flywheels, includingthose presently on vehicle engines, act as sort of mechanical batteries, storingenergy by spinning. Friction, of course, is their enemy. In new flywheeltechnology plans are to create a nearly frictionless environment?essentially avacuum?around the flywheel by enclosing it in a shell and mounting it onliquid or magnetic bearings. To create electricity, magnets mounted on theflywheel would pass close by tightly wound wires lining the shell’s interior. Drawbacks are that charging such a system requires some initial force to get theflywheel up to operating speed (which can be as high as 100,000 rpm) and thatlightweight but strong composites instead of common metals must be used toconstruct the flywheel to prevent it from breaking apart. 3.
Hybrids Hybridvehicles typically feature two different power sources?working either inparallel or in series?to propel the vehicle. Much research is under waycombining gasoline or diesel-fueled internal combustion engines withelectrically powered motors to get the job done. In a parallel setup, both powersources drive the wheels. For example, an electric motor may accelerate the carto highway speeds, whereupon a small internal combustion engine, or ICE, thentakes over to power the wheels for cruising. With this system, the ICE need onlybe large enough to maintain speed, and the energy supply for the electric motorneed not provide long range.
In a series setup, power from both engine sourcesis sent to a single additional motor or controller that drives the wheels. Insuch a vehicle, an electric motor might run on batteries that in turn could becharged by a generator operated by a small internal combustion engine. Such acombination could extend the range of an EV considerably. Already there has beenan example of a hybrid vehicle, albeit extreme: the Chrysler Patriot race carproject of the early ?90s.
The Patriot used liquefied natural gas to fuel aninternal combustion engine that, in turn, spun two turbines providingelectricity. A flywheel generated additional power. All the electricity wascontrolled by a computer that both delegated which power source (turbines orflywheel) to draw from and then directed that power to the motor driving thewheels. In all, the turbines and flywheel produced about one megawatt of energy,which was how the Patriot was expected to reach speeds approaching 200 mph.
These new power sources will revolutionize the transportation industry. Theywill replace gasoline as the predominant enegy source of our vehicles.