Hybrid electric vehicles are powered by an internal combustion engine and one or more electric motors, which uses energy stored in batteries. A hybrid electric vehicle cannot be plugged in to charge the battery. Instead, the battery is charged through regenerative braking and by the internal combustion engine. The extra power provided by the electric motor can potentially allow for a smaller engine. The battery can also power auxiliary loads and reduce engine idling when stopped.

1. Dr.G.Nageswara Rao
Professor , EEE Department
Lakireddy Bali Reddy College of Engineering (LBRCE)
Hybrid Electric Vehicle
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2. Hybrid Electric Vehicles
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Design
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Types
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History
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Hybrid Electric Vehicle (HEV):
A Hybrid Electric Vehicle is a type of vehicle that uses a
combination of an Internal Combustion (IC) engine and an electric
propulsion system. The electric powertrain may enhance fuel
efficiency, increase performance, or independently propel the
vehicle on pure electric power, depending on the type of hybrid
system.
A hybrid vehicle combines any two power (energy) sources. Possible combinations
include diesel/electric, gasoline/fly wheel, and fuel cell (FC)/battery.
Typically, one energy source is storage, and the other is conversion of a fuel to
energy.
The combination of two power sources may support two separate propulsion
systems. Thus to be a True hybrid, the vehicle must have at least two modes of
propulsion

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The below points explain how an HEV works.
o Powering a hybrid electric vehicle is an IC engine and an electric motor.
o The electric motor utilizes the electrical energy stored in the battery pack.
o The battery pack gets charged via regenerative braking or through a
generator that is run by the internal combustion engine.
o An HEV does not need to be plugged into a power source to charge the
battery.
o The electric motor and IC engine work in conjunction to propel the vehicle.
o The additional power from the electric motor assists the engine, and it
enhances the performance and improves the fuel economy.
o The battery pack can also power other electrical components such as
lights.
o The electric powertrain also saves fuel via the engine start/stop
technology, wherein the engine automatically shuts off when idle and
starts automatically when the driver presses the throttle pedal.
How does an HEV work?

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COMPONENTS OF A HYBRID ELECTRIC VEHICLES

6. COMPONENTS OF A HYBRID ELECTRIC VEHICLES
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1) BATTERY (AUXILIARY)
2) DC/DC CONVERTER
3) ELECTRIC GENERATOR
4) ELECTRIC TRACTION MOTOR
5) EXHAUST SYSTEM
6) FUEL FILLER
7) FUEL TANK (GASOLINE)
8) INTERNAL COMBUSTION ENGINE (SPARK-IGNITED)
9) POWER ELECTRONICS CONTROLLER
10) THERMAL SYSTEM (COOLING)
11) TRACTION BATTERY PACK
12) TRANSMISSION

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ADVANTAGES OF HYBRID EVs:
Switching to a hybrid vehicles has many advantages, a few of which
we have highlighted below
1. Environmentally Friendly
2. Economical
3. Less Fossil Fuel Dependent
4. Regenerative Braking System
5. Light Build
6. Higher Resale Value
DISADVANTAGES OF HYBRID EVs:
1. Less Power
2. Expensive to Purchase
3. Poorer Handling
4. High Maintenance Cost
5. High Voltage Batteries

8. Types of Hybrid Electric Vehicles
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1. Series hybrid
In a series hybrid system, the IC engine powers the electric generator, which drives
the electric motor and charges the battery. In this setup, the engine does not directly
power the wheels. Series hybrid is also called a range extender since the engine
powers the electric motor and the battery pack.
2. Parallel hybrid
In this system, both the engine and electric motor work parallel to propel the vehicle.
The engine and the electric motor deliver optimum power for the efficient functioning
of the car. The battery pack gets charged via regenerative braking. If you wonder
what regenerative braking is, here’s a brief explanation. Regenerative braking is a
process of utilizing the kinetic energy produced while slowing the vehicle down to
charge the battery pack.
3. Series-parallel hybrid
A series-parallel is a flexible system wherein the IC engine, and electric motor can
work in conjunction or independently. The power delivery or the power distribution
helps the vehicle achieve maximum efficiency in terms of power output or fuel-
efficiency.

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Types of Hybrid Electric Vehicles

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Schematic of Series System Schematic of Parallel System

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H.E.V. System In Automobile

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LIMITING PHYSICS:
The performance of an H.E.V. is limited by its efficiency and its
capacity to carry its own fuel. Battery capacity and fuel energy
density are both limits on the amount of power a vehicle can sustain.
The three major types of battery are lead acid (the most common car
battery), NiCd (nickel-cadmium) and the newer NiMH (nickel-metal-
hydride). Battery specific energy, specific power, cost, and life are the
most important factors in choosing a battery.
Specific energy(W-h/kg) ,Specific power(W/kg) , Approximate cost($/kWh), Approximate life
(cycles to 80% discharged)
Lead-acid 35 200 125 450
NiCd 40 175 600 1250
NiMH 70 150 540 1500

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Series hybrid electric vehicle operating modes

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Parallel hybrid electric vehicle operating modes

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series-Parallel hybrid electric vehicle operating modes

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Difference between Electric Vehicles and Hybrid Electric Vehicles

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Thanks!
If any questions?
You can find me at: gnrgudipudi@lbrce.ac.in