WHAT MAKE A HYBRID
Any vehicle is a hybrid when it combines two or more sources of
power. Many people have probably owned a hybrid vehicle at some
point. For example, a mo-ped (a motorized pedal bike) is a type of hybrid
because it combines the power of a petrol engine with the pedal power of
its rider. Giant trucks and pulling trains are diesel electric hybrid.
Submarines are also hybrid vehicles. Some are nuclear-electric and some
Any vehicle that combines two or more sources of power that can
directly or indirectly provide propulsion power is a hybrid. The gasoline-
electric hybrid car is just a cross between a gasoline-powered car and an
Central Polytechnic College, Thiruvananthapuram. PAGE NO- 1
GASOLINE POWERED CAR
The figure shows a schematic representation of gasoline-powered
car. It consists of a fuel tank, an engine and transmission. The fuel from
the fuel tank helps the running of engine. The power produced is
transmitted to the transmission system and it turns the road wheels.
Engine Transmission Fuel Tank
Engine Fuel Tank
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PROBLEMS WITH GASOLINE POWERED CAR
To be useful for a car must meet certain requirements. A car should
be able to.
a) Drive at least 300 miles between refueling.
b) Refueled quickly and easily.
c) Keep up other traffic on the road.
A gasoline car meets these requirements but produces a relative large
amount of pollution and generally gets poor mileage. On the other hand
the electric car produces almost no pollution but it can only go upto 100
miles between charges and the problem is that it is very slow and
inconvenient to recharge.
When driver for quick acceleration causes a car to be much less
efficient than they could be. Less powerful engine gets better mileage
than an identical car with a more power engine. The amusing thing is that
most of what we require a car to do uses a small percentage of its hybrid
power when driving along the freeway at 60 mph.
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EVOLUTION OF HYBRID
The hybrid is a compromise. It attempts to significantly increase the
mileage and reduce the emissions of a gas-powered car while overcoming
the shortcomings of an electric car. It is wonder that while any one
would build such a complicated machine when most people are perfectly
happy with their gasoline-powered car. The reason is two told that is to
reduce tail pipe emission and to improve the mileage.
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ELECTRIC POWERED CAR
The figure shows a typical electric car. It consists of a set of
batteries, electric motor and transmission. The batteries provide power to
electric motor and the motor turns the transmission.
Motor Transmission Battery
Electric Motor Battery
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Two power sources found in a hybrid car in different ways. It has
a fuel tank, which supplies gasoline to the engine and set of batteries that
supplies power to an electric motor. Both the engine and the electric
motor can turn the transmission at the same time, and the transmission
then turns the road wheels. The different ways in which the power
sources found in a hybrid car are describe as follows.
1) Parallel Hybrid
2) Series Hybrid
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PARALLEL HYBRID CAR
The figure shows a typical parallel hybrid. You'll notice that the
fuel tank and gas engine connect to the transmission. The batteries and
electric motor also connect to the transmission independently. As a result,
in a parallel hybrid, both the electric motor and the gas engine can
provide propulsion power.
Engine Transmission Battery Fuel Tank
Fuel Tank Engine
Battery Electric Motor
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SERIES HYBRID CAR
The figure shows a series hybrid. The gasoline engine turns a
generator, and the generator can either charge the batteries or power an
electric motor that drives the transmission. Thus, the gasoline engine
never directly powers the vehicle. Take a look at the diagram of the series
hybrid, starting with the fuel tank, and 4- cylinder engine, Generator,
Battery, Electric motor and transmission.
Electric Motor Transmission Battery Fuel Tank Engine
Fuel Tank Engine Generator
Battery Electric Motor Transmission
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Hybrid car contains the following parts.
1) Gasoline engine
The hybrid car has a gasoline engine much like the one you will find
on most cars. However, the engine on a hybrid is smaller and uses
advanced technologies to reduce emissions and increase efficiency.
2) Fuel tank
The fuel tank in a hybrid is the energy storage device for the gasoline
engine. Gasoline has a much higher energy density than batteries do. For
example, it takes about 1,000 pounds of batteries to store as much energy
as 7 pounds of gasoline.
3) Electric motor
The electric motor on a hybrid car is very sophisticated. Advanced
electronics allow it to act as a motor as well as a generator. For example,
when it needs to, it can draw energy from the batteries to accelerate the
car. But acting as a generator, it can slow the car down and return energy
to the batteries.
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The generator is similar to an electric motor, but it acts only to
produce electrical power. It is used mostly on series hybrids.
The batteries in a hybrid car are the energy storage device for the
electric motor. Unlike the gasoline in the fuel tank, which can only power
the gasoline engine, the electric motor on a hybrid car can put energy into
the batteries as well as draw energy from them.
The transmission on a hybrid car performs the same basic function as
the transmission on a conventional car.
Central Polytechnic College, Thiruvananthapuram. PAGE NO- 10
USES OF HYBRID CAR
California emissions standards announced how much of each type
of pollution a car is allowed to emit in California. The amount is usually
specified in gm/mile of carbon monoxide.
The key thing here is that the amount of pollutions allowed does
not depend on the mileage a car gets. But a car that burns twice as much
fuel to go a mile will generate approximately twice as much pollution.
The pollution will have to be reduced by the emission control equipment
on the car. So decreasing the fuel consumption of the car is one of the
surest ways to decrease emission.
Carbon dioxide is another type of pollution a car produce it cause
global warming. So the hybrid cars are used to reduce the air pollution.
They produce very less.
Amount of exhaust gases like carbon dioxide and carbon monoxide
with respect to the other vehicles. The pollutants in this type of gas is
very less and is in a controlled manner.
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HYBRID MILEAGE TIPS
You can get the best mileage from a hybrid car by using the same kind of
driving habits that give you better mileage in your gasoline-engine car:
a) Drive slower
The aerodynamic drag on the car increases dramatically the faster
you drive. For example, the drag force at 70 mph (113 kph) is about
double that at 50 mph (81 kph). So, keeping your speed down can
increase your mileage significantly.
b) Maintain a constant speed
Each time you speed up the car you use energy, some of which is
wasted when you slow the car down again. By maintaining a constant
speed, you will make the most efficient use of your fuel.
c) Avoid abrupt stops
When you stop your car, the electric motor in the hybrid acts like a
generator and takes some of the energy out of the car while slowing it
down. If you give the electric motor more time to slow the vehicle, it
can recover more of the energy.
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Besides a smaller, more efficient engine, today's hybrids use many
other tricks to increase fuel efficiency. Some of those tricks will help any
type of car get better mileage, and some only apply to a hybrid.
1) Recover energy and store it in the battery
Whenever you step on the brake pedal in your car, you are removing
energy from the car. The faster a car is going, the more kinetic energy it
has. The brakes of a car remove this energy and dissipate it in the form of
heat. A hybrid car can capture some of this energy and store it in the
battery to use later. It does this by using "regenerative braking." That is,
instead of just using the brakes to stop the car, the electric motor that
drives the hybrid can also slow the car. In this mode, the electric motor
acts as a generator and charges the batteries while the car is slowing
2) Sometimes shut off the engine
A hybrid car does not need to rely on the gasoline engine all of the
time because it has an alternate power source -- the electric motor and
batteries. So the hybrid car can sometimes turn off the gasoline engine.
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3) It uses advanced aerodynamics
This is used to the air resistance. This helps the hybrid car to increase
its efficiency. A less power is required when the car is made in an
4) It uses small efficient engine
The engine in a hybrid weight only 56 kg and it is a small, 1 litre,
three cylinder that produces 67 HP and 5700 rpm. The additional power
provided by the small electric motor is able to accelerate the hybrid car
from 0-60 mph in about 11 seconds.
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ADVANTAGES OF HYBRID CAR
1) Decreasing fuel consumption while it turns reduce emission.
2) Pollution is reduced considerably
3) Improve mileage.
4) Reduced tail pipe emission
5) Refueling problem reduced
6) No need of more fuel consumption at the time of acceleration.
7) Uses small engine and components their by reduces weight.
8) Better performance.
Central Polytechnic College, Thiruvananthapuram. PAGE NO- 15
WHAT’S AVAILABLE NOW
Three hybrid cars are now available in the United States -- the
Honda Civic Hybrid, the Honda Insight and the Toyota Prius. We will be
discussing the latter two, and although both of these cars are hybrids, they
are actually quite different in character.
The Honda Insight, which was introduced in early 2000 in the
United States, is designed to get the best possible mileage. The Insight is
a small, lightweight two-seater with a tiny, high-efficiency gas engine.
The Toyota Prius, which came out in Japan at the end of 1997, is
designed to reduce emissions in urban areas. It meets California's super
ultra low emissions vehicle (SULEV) standard. It is a four-door sedan
that seats five, and the power train is capable of accelerating the vehicle
to speeds up to 15 mph (24 kph) on electric power alone. The Prius was
honored as the 2004 North American Car of the Year.
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The hybrid car gives very good mileage and it produces less
pollution. So in the incoming years the hybrid car will become the most
common vehicle in the world. Hybrid car produces less pollution than
gasoline powered car and good mileage than electric car.
Central Polytechnic College, Thiruvananthapuram. PAGE NO- 17
Autocar April 2004
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