Electric Cars: Types of electric vehicles


PAVOL BAUER: Ladies
and gentlemen, welcome. We normally hear about several
types of electric vehicles. They are hybrids, plug-in hybrids,
battery electric vehicles, and many others. In this section, we will talk about
the types of battery vehicles. And we will learn how to identify
an electric vehicle type. Vehicles can be classified
based on drive-train and fuel type, such as conventional
internal combustion engine vehicle, the alternative fuel internal
combustion engine vehicle, and the electric vehicle. The internal combustion
engine is commonly referred by its short name, ICE. The conventional internal
combustion engine vehicle includes the gasoline
and diesel vehicles. The alternative fuel internal
combustion engine vehicle refers to vehicles that run on a
fuel other than a gasoline or diesel, like autogas, natural
gas, biofuel, or hydrogen. In all forms of internal
combustion engine vehicles, that drive-train is mechanical. In contrast, electric vehicles
use an electric drive-train for the propulsion. In this lecture, we will
focus on electric vehicles. While battery electric vehicles have
an [? electrified ?] drive-train, they can be classified based on their
energy sources, their propulsion devices, and how their propulsion
devices are hybridized. In general, we have
hybrid electric vehicle, plug-in hybrid electric vehicle,
battery electric vehicle, fuel cell electric vehicle, and in
the future, solar electric vehicle. The hybrid electric vehicle sources its
energy solely from gasoline or diesel, while it uses both the electric
motor in combination with the battery and the combustion
engine for propulsion. The plug-in hybrid electric vehicle is
similar to the hybrid electric vehicle, in that it uses both an engine and
an electric motor for propulsion. The difference is that the battery
of a plug-in hybrid electric vehicle can be charged by electricity
via charging port. In contrast, the battery electric
vehicle does not have an engine and is purely powered by
electricity instead of fossil fuels. Further, the propulsion is
solely driven by electric motor. Finally, in the case of a fuel
cell and solar electric vehicle, the energy is directly sourced
from hydrogen using a fuel cell or from solar panels,
respectively, while the propulsion is done using an electric motor. Now let’s look at these
vehicles one by one. For reference, let us start with the
gasoline and diesel vehicles that use an internal combustion
engine for propulsion. A gasoline car typically uses a
spark-ignited engine rather than the compression-ignited systems
used in diesel vehicles. The engine uses a complex
mechanical transmission system to transfer power to the wheels. Similar to a gasoline vehicle,
hybrid electric vehicles are powered by an internal
combustion engine as well. However, in addition, an electric
motor can propel the vehicle by using energy stored in the batteries. The battery is in turn charged
by drawing energy from the engine by using the electric motor
as an electric generator. To operate the motor and generator mode,
a clever power electronic motor drive is used. The extra power provided by the electric
motor allows for a smaller engine. Further, the motor allows the engine to
be operated in its optimal efficiency point, resulting in a
better fuel economy. What we have just seen is a
parallel hybrid architecture where both the engine and the motor
can power the wheels at the same time. A serious hybrid electric vehicle on
the other hand, works differently. The internal combustion engine
is used to drive a generator and provide electrical power
for the traction motors and to charge the battery. This is a common
propulsion method, which has been used in
locomotives for many years. The traction motor is
the only power supply you need to be the direct
connection to the wheels. The advantage is that the
internal combustion engine can be operated at its
most efficient point to generate the necessary current
for drawing the traction motor or charging the battery. The third type of hybrid is the
series-parallel or dual-mode hybrid. This has the flexibility to operate
in either series or parallel mode by using a power split. It has a generator to charge the
battery, as seen in the series hybrid. And it has also an engine and motor,
simultaneously powering the wheels as seen in the parallel hybrid. Although this type of
architecture is more flexible in terms of driving modes, it
is also more complex and, of course, costly. The Toyota Prius is an example of
a hybrid electric vehicle based on the series parallel architecture. Plug-in hybrid electric vehicles are
similar to hybrid electric vehicles in that they have both an
engine and motor for propulsion. The main difference lies in the fact
that plug-in hybrid electric vehicle batteries are larger and
can be externally charged using the onboard charger. This is beside the fact
that the battery can be charged using the internal
combustion engine while driving. This enables the plug-in
hybrid electric vehicles to use the electric motor during
larger periods of time when driving. That means for larger distances. It means that a plug-in
hybrid vehicle can drive electric for most
city commutes and switch to fossil fuels for long highway
rides, removing any range anxiety. What is shown here is a plug-in
hybrid electric vehicle based on parallel [? drive ?] architecture. Similar to what has been seen before,
a plug-in hybrid electric vehicle can be built based on the series and
series-parallel architectures as well. The Chevrolet Volt is an example of a
plug-in hybrid electric vehicle based on a series-parallel architecture. The disadvantage of the
hybrid electric vehicle and plug-in hybrid electric vehicle is
that they continue to use fossil fuels and has had tailpipe emissions. To overcome this, the battery electric
vehicles or all electric vehicles have an only electric motor and
no internal combustion engine. The vehicle uses a large
traction battery pack to power the electric motor. And the battery must be charged from
a power outlet where it is parked. The Tesla Model S is an example
of a battery electric vehicle. Next, we look at a fuel
cell electric vehicle. A fuel cell electric vehicle
substitutes the larger battery of a battery electric
vehicle for a fuel cell stack to generate electricity
from the hydrogen fuel. Unlike a battery, a fuel
cell is not a storage device, but a component that produces direct
current from a chemical reaction. A small battery is still
used as an energy buffer and to power the electric
motor using the motor drive. A fuel cell vehicle has the
advantage of short refueling times and extended driving range when
compared with battery electric vehicles. Here are two examples of
fuel cell electric vehicles– the Hyundai Tucson and the Toyota Mirai. Now that we know all
electric vehicle types, let us compare them based on the
factor called hybridization rate. The hybridization rate is a
measure used to describe how strongly the power-train is hybridized. This level is determined by the
role that the electric motor has in the performance of the car. It is defined as the ratio of
electric power to total power and is described by the equation
where P em is the power provided by electric machine and P
ice is the power provided by the internal combustion engine. The classification for different
values of hybridization rate is shown in this bar chart including
typical values of the power rating of the electric motor. On both sides of this bar, we
can see the internal combustion vehicle hybridization rate is 0 and the
battery electric vehicle hybridization rate is 1. When the hybridization rate
value is smaller than 0.24, this hybrid electric vehicle is
considered to be a micro-hybrid. When the hybridization rate
is between 0.24 and 0.38, it is then distinguished as
the semi- or mild-hybrid. When the hybridization
rate is higher than 0.38, we can then consider
it as a full hybrid. Apart from that, as
we introduced before, if the battery of a
hybrid electric vehicle can be charged from a charging
port, it is classified as a plug-in hybrid electric vehicle. So to wrap up, this
table shows the overview of all types of electric vehicles. In case of internal
combustion engine vehicles, they are solely powered by
the internal combustion engine and has the most emissions. Hybrid electric vehicles and
plug-in hybrid electric vehicles are powered by both an internal
combustion engine and an electric motor that uses energy stored in the battery. The battery is charged by the
internal combustion engine for both. For a plug-in hybrid
electric vehicle, the vehicle can be plugged in an electric
power source to charge the battery. Battery electric vehicles use no fossil
fuels and have zero tailpipe emissions. Like a plug-in hybrid electric
vehicle, the electric vehicle batteries are charged by plugging the vehicle
into an electric power source. Finally, a fuel cell electric
vehicle uses fuel cell powered by the hydrogen and
battery to power vehicle using an electric drive-train.

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