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Electric cars vs Petrol cars


Electric cars or internal
combustion engine cars: Which is better? Electric cars were in their
heyday back in 1900. But a sudden rise in petrol engine cars, accompanied by battery technology inefficiencies
killed electric cars by 1920. However, with recent improvements in
battery technology and power electronics, electric cars have made a strong comeback. We will compare these totally
different technologies scientifically, and come to understand which is superior. An IC engine is the prime mover
in petrol cars. The fuel supplied to the engine produces
combustion and enough pressure and temperature
energy to move the pistons. The linear motion of the piston is
transferred to rotary motion using a slider crank mechanism. A transmission is used to transfer this rotation to the drive wheels. In an electric car the power source is
from a battery pack. An inverter converts the DC battery power
into three-phase AC. The three-phase AC can turn
an induction motor, which will thus turn the drive wheel. Now, let us directly compare
these technologies: In an IC engine the force and
power production is never uniform. The reciprocating components cause
substantial mechanical balancing issues. In addition, the engine is not self-started. Many accessories are needed to
sort out these issues, which makes an IC engine quite heavy. Such issues are not there
in an electric motor. The induction motors work with the help of a rotating magnetic field,
generated by the stator. You can easily control motor speed by adjusting the frequency of
the AC power input. They produce uniform power and
speed output and are self-started. For these reasons, an induction motor is
much lighter than an IC engine, and, at the same time, produces much
greater power and torque output. It is interesting to note that both the IC engine and
induction motor require cooling. Both the prime movers must reject
the waste heat generated in order to keep the temperature
within a certain limit. However, it is worth noting that
the waste heat generated by an induction motor is much
lower than that of an IC engine. The main advantage of an IC engine car is
the ease with which it can be refuelled. A petrol car can be refuelled
in 5 minutes or less. However, recharging electric cars can take
at least 1 hour as of this present moment. Another major advantage of
petrol cars over electric cars pertains to their high energy density. The energy density of current
lithium-ion battery is nowhere near to that of the gasoline. Both these cars produce
comparable travel ranges. You can just compare the size and
weight of their energy storage devices. The poor energy density of
the battery produces a huge weight penalty to the electric car. The huge weight of the car reduces
the coefficient of friction between the tire and road considerably
making cornering difficult The battery pack also has huge heat
generation issues: If you tear down the battery pack
of an electric car, you will see that the battery pack
is a collection of common lithium-ion cells
that you might use in your daily life. Continuous liquid cooling is required to
keep battery temperatures at normal levels. The removed heat is rejected to
the atmosphere via a radiator. A petrol car’s energy storage part does
not require any such cooling mechanism. The battery pack of electric cars does
have advantages as well. Because the heavy battery pack is sitting
very low to the ground, it lowers the center of gravity
and increases car stability. Thus, overall safety is increased. The large battery pack is also
spread across the floor, offering structural rigidity
against side collisions. Another primary difference visible
from these visuals, is that in an IC engine car, a complex
exhaust gas treatment is needed to keep pollutants and noise
at statutory levels. Now, let’s compare the power dynamics
of these two technologies: Electric cars are the clear winner here. IC engines cannot be operated beyond
a certain speed range. This necessitates the use of a complex and costly transmission mechanism
for speed control. The motor can work efficiently
in a wide speed range. So, in an electric car speed can
be controlled directly from the motor. As a result, a speed varying transmission
is not required for an electric car. Induction motor speed is accurately
controlled by the inverter, simply by adjusting the output power frequency.
In fact, improvements made in the last decade to the software behind
inverter power electronics, played a key role in the revival
of electric cars. The electric car can produce
great torque even at the start, whereas an IC engine car
will struggle at low RPM. A DC motor is thus needed to take
the engine to the optimum RPM range at the start. Moreover, the torque and power of
an electric motor can be controlled instantaneously while the IC engines
have a low response. This, in effect, leads to far superior
traction controls in electric cars. Electric cars have inherent advantages
when it comes to regenerative braking. The same induction motor acts
as a generator here. In a petrol car, in order to achieve
regenerative braking, you must install a separate
BLDC motor and a battery pack. Before concluding the video,
let’s solve the big question: Which car is more economical? An electric car is much costlier
than an average petrol car. However, to get the full picture, you must
also compare the cost required to travel a mile. The calculation based on current
US gasoline and electricity prices, shows that electric cars are at least
one-third cheaper compared to petrol cars. Moreover, the maintenance cost of
electric cars is also low when compared to IC engine cars. As you might already be aware, electric cars
are much safer than internal combustion cars. With technological advancements in
internal combustion engines almost saturated and rapid development of electric cars
taking place. One can clearly see how electric cars have
an edge over IC engine cars as the cars of the future. To learn more about
this interesting topic, please check out this excellent video
by the channel Kyle drives. Kyle is an automobile expert and
Motorsports design and analysis engineer. Please support us at Patreon so that we
can sustain our free educational service. Thank you.

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