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What is an Electric and/or hybrid Vehicle?? Hybrid
and
Electric Vehicle Overview
Everyone has her own definition and description of
the various types and designs encompassed by this evolving form of
transportation. What follows is simply our attempt at providing a structure
within which to discuss and evaluate these up-and-coming electric (and
partly-electric) vehicles. First off, we should recognize that there is
nothing really new going on here at all. Electric vehicles have existed
since before the turn of the last century and initially out-performed those
vehicles being powered by gasoline. Interestingly, many of the early
electric vehicles were later used extensively by women; most often for
in-town travel. Even the new so-called “hybrid” (or partly-electric)
vehicles, often heralded as being “the latest advancement in
electrically-powered vehicle technology” have been around for decades, just
not in our garages. Case in point, the next time you see a locomotive
pulling a few hundred freight cars you can rest assured that you are
witnessing the power and reliability of a long-time hybrid known,
descriptively enough, as a diesel-electric.
So then, having recognized that our current
offering of electric vehicles are not really new but more just a long-proven
idea mated with 21st century materials what is it exactly that qualifies as
an electric vehicle and how do they work?
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Categories of Electric Vehicles
It may be helpful when considering electric
vehicles to first arrange them into one of two broad categories: Pure
Electrics and Hybrid Electrics. Within the Pure Electric category are the
battery-powered vehicles that have no primary on-board means of generating
electricity. All the electrical power must come from energy stored in the
batteries themselves. Within the Hybrid-electric category are all the
vehicles that do have a primary on-board source of electrical power. This
on-board electrical power source could be as simple as a regular gasoline
engine mated to a mechanical electrical generator, or something as exotic as
a
solar panel or a
fuel
cell. But Why Bother? At first the idea of mating a gasoline engine to a
mechanical electrical generator just to produce electricity which, in turn,
will be used to drive an electric motor which, in turn, will help drive the
wheels may all seem like “much to do about nothing”. However there are great
advantages even in this the most complex combination, as we shall see later. That said, there are certainly far simpler ways to
produce electricity than by mechanical means. Electricity can, for instance,
be created either chemically though the use of “fuel cells” or
photovoltaically, using solar panels. The direct creation of electricity
eliminates the need to first convert mechanical energy into electrical
energy by way of a generator, eliminating both the generator and the engine
that drives it. While simple and quiet, fuel cells still need a
“fuel supply” (generally hydrogen and oxygen) to make them work. Thus even
this type of hybrid-electric needs to stop to refuel. The only type of
hybrid vehicle that can avoid stopping to refuel is one that is solar
powered since, in effect it refuels constantly while driving. Constantly
that is during the day, at certain latitudes, at certain times of the year,
and under certain meteorological conditions.
Confused Yet? We will pause briefly at this point to comment on
two items that may possibly have already caused some confusion (or
argument!) in the minds of our more careful readers. The first of these is
the fine but important distinction between a “hybrid engine” and a “hybrid
vehicle”. The second item we will examine is our decision to classify the
solar-powered vehicle as a “hybrid” rather than as a “pure” electric. As to the first item, be aware that relatively few
“hybrid vehicles” utilize anything that could rightfully be considered to be
a “hybrid motor” although such all-in-one “engine/generator/electric motor”
combinations certainly do exist. The Honda Insight is one example. In these
“hybrid-motored” vehicles the traditional engine/generator system is
mechanically connected to the electric motor as well. By way of contrast, in
the increasingly more common “distributed” design, the only physical
connection between the engine/generator and the electric motor may be by way
of high voltage wiring. The distributed approach allows for the placement
of the electric motor far away from the engine/generator. Of course, even
when the engine/generator is mechanically separate from the electric motor
it can still be said to be a “hybrid vehicle” even if it cannot be said to
be a vehicle that has a “hybrid engine”. You may well find this to be too
fine a distinction, perhaps, but one that might come in handy later. As to the second item mentioned, that being our
classification of solar powered cars as “hybrids” we can only say that we
believe those who prefer to classify them as “pure” electrics do so for
reasons of status and praise rather than physics. Unlike, say, solar heated
water panels, solar vehicles most certainly blend two very different
technologies, namely electric motors and photovoltaic panels. Not even the
fact that sunlight is free, natural, and readily available can make the
vehicle that it powers any less a “hybrid” given the basic meaning of that
term: On-board generation of primary electrical power and an electric motor
which uses it. The Good, the Bad and The Okay But enough about the finer points of electric
vehicle classification! The end goal here is to create a framework within
which the pros and cons of each of the various types of electric vehicles
can be discussed and evaluated. However, before comparing and contrasting these
various types, it would be most productive to take a quick look at the
overriding principles and the resultant operational
advantages that apply to
virtually any form of electric vehicle. Off to the Races
So with the above as a background, we
are now ready to look a little closer at each of the individual types of
electric vehicles: Pure electrics
(meaning
strictly battery powered vehicles) and
Hybrids
and their advantages
in relation to safety,
convenience, efficiency and economy.
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