DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
Why fuel efficiency is important?
History of HEV
Components of HEV
Configurations of HEV
Modes of operation
How hybrid saves fuel?
Any vehicle that combines two or more sources of power is said to be hybrid.
A Hybrid Electric Vehicle(HEV) augments an electric vehicle with a second source of
power( alternate power unit- petrol, diesel etc.)
Combines a conventional internal combustion engine propulsion system with an
electric propulsion system.
A hybrid can achieve the cruising range and performance advantages of conventional
vehicles with the low noise, low exhaust emission.
Modern HEVs make use of efficiency-improving technologies such as regenerative
brakes, which converts the vehicle's kinetic energy into electric energy to charge the
battery, rather than wasting it as heat energy as conventional brakes do.
Provides better mileage and less use of fuel.
WHY IS FUEL EFFICIENCY IMPORTANT?
World energy shortage and growing demand have caused energy crises.
The reserves are decreasing at an alarming rate where as the demand is increasing
day by day.
Fuel price increasing day by day.
Pollution increasing creating severe impact in the world.
According to the Institute of
Mechanical Engineers, there
are 1.3 trillion barrels of
proven oil reserve left in the
world's major fields, which at
present rates of consumption
should last 40 years.
Thus to reduce consumption
many mitigating ways and
technologies are used.
As automobile sector uses the
most fuel, hence fuel must be
used efficiently and should not
HISTORY OF HEV
Steam Engine Car, British inventor Goldsworthy.
85 miles round trip took 10 hours (14 km/h).
First electric car was build in Scotland.
The London Electric Cab Company used a 40-cell battery and 3 horsepower electric
Could be driven 50 miles between charges.
The German Dr. Porsche, at age 23, Built the world's first front-wheel-drive.
Porsche's second car was a hybrid, using an internal combustion engine to spin a
generator that provided power to electric motors located in the wheel hubs. On
battery alone, the car could travel nearly 40 miles.
US car companies made 1,681 steam, 1,575 electric and 936 gasoline cars.
In a poll, electric was the first choice, followed by steam.
Henry Ford overcame the gasoline engine issues: noise, vibration, and odor
Produced low-priced, lightweight, gas-powered vehicles.
Within a few years, the electric vehicles failed. A hybrid combination came in
Hybrid electric vehicles did not become widely available until the release of the Toyota
Prius in Japan in 1997, followed by the Honda Insight in 1999.
Toyota, Audi, Honda, Ford, followed by other main car manufactures introduced new
generation of electric and hybrid cars.
The Toyota Prius II won 2004 Car of the Year Awards from Motor Trend Magazine
and the North American Auto Show.
Toyota was surprised by the demand and pumped up its production from 36,000 to
47,000 for the U.S.
THE LOHNER-PORSCHE MIXTE HYBRID WAS THE FIRST GASOLINE-ELECTRIC HYBRID
COMPONENTS OF HEV
Components used in hybrid electric vehicles are given below:
Gasoline engine - The engine on a hybrid will be smaller and lighter, and is more
efficient than the engine in a conventional vehicle. Use advanced technologies
further reduce emissions.
Fuel tank - The fuel tank in a hybrid is the energy storage device for the gasoline
Electric motor - The electric motor on a hybrid car is very sophisticated. Electric
motor used in hybrid cars are usually dc series motor since it’s versatile.
Generator - It acts only to produce electrical power. It is used mostly on series
Power split device –The power split device is a clever gearbox that hooks the
internal combustion engine and D.C.motor together.
Batteries - The batteries in a hybrid car are the energy storage device for the
electric motor. The batteries used in HEV is Ni-Cd cells since its lighter than the
lead acid cells and its also mechanically strong and can stand very rough use.
CONFIGURATIONS OF HEV
This is called a series hybrid system
because the power flows to the
wheels in series. A series hybrid
system can run a small-output
engine in the efficient operating
region relatively steadily, generate
and supply electricity to the electric
motor and efficiently charge the
battery. This system is being used in
the Coaster Hybrid.
In a parallel hybrid system,
both the engine and the
electric motor drive the
wheels, and the drive
power from these two
sources can be utilized
according to the prevailing
conditions. This is called a
parallel hybrid system
because the power flows
to the wheels in parallel.
This maximizes both series
and parallel systems, it has
two motors, and depending
on the driving conditions,
uses only the electric motor
or the driving power from
both the electric motor and
the engine, in order to
achieve the highest efficiency
USAGE OF ENGINE AND MOTOR IN DIFFERENT CONFIGURATION
Scenario 1: Low speed - Power is provided by
electric motor using energy supplied by the
Scenario 2: Braking – Kinetic energy is
converted to electric energy during
regenerative braking by electric motor and
supplied to battery.
Scenario 3: High speed – Power is provided
by IC engine and electric motor via
generator. Generator also charge battery
during high speed.
BLOCK DIAGRAM REPRESENTATION OF MODES OF OPERATION
HOW HYBRID SAVES FUEL?
Engine is turned off at:
Lower speed (say less that 15 km/h), an electric motor drives the
car until speed reaches a certain limit, then engine kicks in
When vehicle is stopping or going downhill, engine is turned off,
Regenerative braking is applied
When engine operates in an inefficient mode(e.g. at very high or very
low engine speeds), the electric motor kicks in and assists engine.
Engine is driven to its optimum operating zone
Engine can be made smaller, due to electric motor assistance
ADVANTAGES OF HEV
• Use less oil than ICE.
• Emits less CO2 than ICE.
• Fuel efficiency increased.
• Regenerative braking.
• Reduces the size of ICE.
• Quiet operation.
• Toyota Prius
• Toyota Highlander
• Toyota Auris Hybrid
• Ford Escape
• Honda Insight
• Honda Civic Hybrid
• Honda Accord Hybrid
Toyota Prius Eco 2016 56 58 53 US$650 158 NA 5.9
Toyota Prius (4th gen) 2016 52 54 50 US$700 170 NA 6.3
Toyota Prius (3rd gen) 2015 50 51 48 US$700 179 7/9* 6.6
Toyota Prius c 2015/16 50 53 46 US$700 178 7/8* 6.6
Honda Accord (2nd gen) 2015 47 50 45 US$750 188 7/8* 7.0
2016 46 47 46 US$750 212 7/8* 7.8
Economic and environmental performance comparison among EPA's top ten 2015/16 model
year most fuel efficient hybrid models available in the U.S. market
• Using the concept of hybridization of cars results in better efficiency and also
saves a lot of fuel in todays fuel deficit world.
• A hybrid gives a solution to all problems to some extent.
• Hybrid vehicles promises a practical ,efficient, low pollution vehicle for the
• One can surely conclude that this concept and the similar ones to follow with
even better efficiency and conservation rate are very much on the anvil in
todays energy deficit world.