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Hybrid
Vehicles and Cars
Hybrid electric vehicles
are, again, simply those vehicles with an on-board source for generating
electrical power. This power source can be anything from solar panels, to
fuel cells, to a standard piston engine coupled to an electrical generator.
Having on-board power allows hybrids to selectively chose the source of
mechanical power that is most the more efficacious for powering the car
under the circumstances. For example, electric engines are very efficient in
low speed/high torque applications, while piston engines perform better at
mid- to higher speeds. Using these two sources of power individually, or in
combination, yields a more efficient vehicle overall. The advantages of
electric vehicles in general are discussed in the Overview section. What
follows are the type-specific characteristics of the various hybrids. |
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1) Mechanical Hybrids:
This type includes those hybrids where the primary source of on-board
electrical power is a generator mated to a mechanical engine. There are
principally three types of mechanical engines: Piston, rotary and turbine.
Piston Engines
These are by far the most common type of
mechanical engines, being used in all conventional and most hybrid vehicles.
Called “internal combustion” engines (as the burning of the fuel occurs
within enclosed cylinders) they run most commonly on gasoline, diesel oil or
natural gas, although some have been designed to run on more exotic fare,
like coal dust or alcohol. The main advantage to a hybrid vehicle that
incorporates a piston engine is that it is utilizing a readily available,
proven technology for its primary on-board power source. (The secondary
electrical power source, as always, is regenerative braking, discussed
previously in the Overview section.)
The disadvantage to such a hybrid vehicle is that
its piston engine has all the drawbacks of the engines in conventional
vehicles: Noise, pollution (unless powered by compressed or liquid natural
gas [C/LNG] or propane [LPG]) high moving parts count and poor reliability
with age. The degree of mechanical complexity is certainly not improved when
the electric motor is, itself, connected directly to the piston
engine/generator (in an arrangement previously described in the Overview as
a “hybrid engine”).
Turbine and Rotary Engines.
Both of these engines employ rotating rather than
reciprocating action, resulting in smoother operation, especially at higher
speeds, with fewer moving parts and greater reliability. Trouble is, rotary
engines are not terribly fuel-efficient and turbine engines are radically
expensive and tend to run at temperatures too hot to use in and around
people and property. As of yet, no one has produced a commercially viable
turbine or rotary engine for use in a hybrid electric vehicle, although some
of each have powered a handful of otherwise conventional vehicles.
2) Non-Mechanical Hybrids
Fuel Cells
Fuel cells are devices that produce electricity
via chemical activity as opposed to mechanical activity. Instead of spinning
a mechanical generator to produce electrical power, the fuel cell produces
electricity by capturing the electrical discharges produced when certain
chemicals are combined (or, as is often the case, re-combined).
A separate section in this site is devoted to the
technology involved in utilizing fuel cells to power vehicles. Fuel cells
are also discussed to a lesser degree in the Overview. Suffice it to say,
for the purposes of this section on hybrids, that the fuel cell holds great
promise for producing on-board power in the areas of reliability and
maintenance but provides us virtually no means for current evaluation in
terms of safety, cost or expected availability.
Solar Panels
Our hands-down favourite hybrid vehicle would be
one covered with solar panels and sporting a back-up primary power source,
be it a mechanical system or a fuel cell. Take a moment to think about all
the vehicles baking for hours in the hot sun each day while their owners are
at work. Certainly the power that could be harnessed on most days would be
enough to get those cars home using battery power alone. Once home, an
overnight charge could easily get the car back to work again the next day.
An added plus would be that the interior of the car would stay much cooler
during the day, with most of the sun’s energy absorbed by the solar panels.
Of course, should the trip home require several
detours, or an out and out journey, the back-up primary power system (be it
mechanical or fuel cell) would be there to ensure a worry-free trip.
As it stands, however, we know of no one that has
mated a solar panel to an otherwise perfectly capable hybrid vehicle. That
being the case, we are left with only solar “experiments” rather than
functional solar vehicles. In fact, as close as we have seen the world come
to building an all-in-one solar/hybrid electric vehicle would be the planned
final design configuration of that indomitable unmanned aircraft, the
Helios.
And so, while Australia’s “Solar Challenge” brings
out many highly-efficient one-person solar-powered designs from the top
schools around the world everyone still drives home from the annual event
with the sun beating down on their own vehicle’s bonnet, boot and top, to no
avail.
Perhaps when the price of solar panels drops
and/or the price of gasoline rises someone will think of shading their fuel
or gasoline powered hybrid vehicle with a solar panel or two, picking up a
few more miles to the gallon in the process. Until then, we can only marvel
at how far we have come, and how far we have to go.
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Her
Electric Vehicle 
