Different types and classifications of EHV

1. K C Karthik
2nd sem, M.Tech(A.E)

2. Need Electric and Hybrid vehicles
 Over dependence on petrol/diesel
 Rising petrol/diesel prices
 Pollution and the resultant global warming
 Noise in conventional vehicles
 Need for alternate power sources
 Need for Eco friendly vehicles
 EV, HEV - The solution?

3. Electric vehicles
 An Electric vehicle is an automobile that is propelled by
one or more electric motors, using electrical energy stored
in energy storage device.
 The primary components are motor, controller, power
source, and transmission.

4. Block diagram
An Electric vehicle system

5. Advantages
 No Gas Required
 No Emissions
 Cost Effective
 Low Maintenance
 Pay back period
 Low noise

6. Disadvantages
 High Initial Cost- Many times that of conventional vehicles
 Short Driving Range- Range anxiety
 Recharging takes much longer time than refueling gasoline-
lack of charging infrastructure
 Battery pack takes space and weight of the vehicle which
otherwise is available to the people

7. Concept of hybridization
 Multiple sources of power
 Making ICE work in most efficient range
 Sizing of motor and ICE lower compared to conventional
vehicles and EV

8. Hybrid Vehicles
 The term hybrid vehicles in general usage refer to vehicles with
two or three different type of sources delivering power to the
wheels for propulsion.
 The most common hybrid vehicles have an IC engine and one
or more electric machines for vehicle propulsion.
 The IC engine can be used to generate electric energy ‘on
board’ to power the machines.

9. Classification
 Based on the path of energy flow
 Mechanical power transmission path (MPTP)
 Electrical power transmission path (EPTP)
 Combination of MPTP and EPTP
 Based on architecture
 Series
 Parallel
 Series-Parallel

10. Classification
 Based on degree of hybridization
 Mild
 Power
 Energy
 Charge depleting
 Charge sustaining

11. Mechanical power transmission path (MPTP)
 The primary powertrain components in a conventional ICE
vehicle are engine and transmission. The energy flow in a
vehicle starts from source of energy and ends at wheels with
the delivery of propulsion power known as power
transmission.
Power transmission path in conventional IC engine

12. Electrical power transmission path (EPTP)
 In electric vehicle power transmission is almost electrical
except for coupling devices between electric propulsion motor
and wheels. The coupling device can simply be a gear to match
electric machine speeds to vehicle speeds.
Power transmission path in an electric vehicle

13. Combination of MPTP and EPTP
 The propulsion power is transmitted to wheels through either
MPTP or EPTP or combination of both.
 The MPTP is associated with an IC engine and transmission,
whereas EPTP consists of energy storage system, a generator,
propulsion motor and transmission.

14. Block diagram
A hybrid electric vehicle powertrain

15. Series HEV
 A series hybrid is one in which only one energy converter can
provide propulsion power.
 Only electric motor provides all propulsion power to wheels.
 A downsized IC engine drives a generator, which supplements
batteries and can charge them when it fall below certain charge
level.
 The drawback is size of traction motor, which as to be rated for
max. power requirement of vehicle.

16. Block diagram
Series HEV powertrain

17. Advantages
 Flexibility of location of engine-generator set
 Simplicity of Drive train
 Suitable for short trips with stop and go traffic
Disadvantages
 It needs IC engine, generator and motor
 Motor must be designed for maximum sustained power that vehicle require
such as climbing a high gradient
 All drivetrain components need to be sized for maximum power for long
distance, high speed driving

18. Parallel HEV
 A parallel hybrid is one in which more than one energy
conversion device can deliver propulsion power to the wheels.
 The IC engine and electric motor are configured in parallel
with a mechanical coupling.
 The power requirements of electric motor is lower than that of
series HEV.

19. Block diagram
Parallel HEV powertrain

20. Advantages
 It needs only IC engine and motor/generator
 A smaller engine and motor can be used to get same
performance, until batteries are depleted
Disadvantages
 The control complexity increases, since power flow has to be
regulated and blended from two parallel sources
 The power blending from IC engine and motor needs a
complex mechanical device

21. Series-Parallel HEV
 It combines the benefits of series and parallel architecture with
charge sustaining capability.
 The power-split device divides the output from the engine into
mechanical and electrical transmission paths.
 Even IC engine is also used to charge the battery.
 They are capable of providing continuous high output power
compared to series or parallel powertrain.

22. Block diagram
Series –Parallel combination HEV

23. Drive Modes of Operation

24. Torque characteristics
Electric motor and IC engine torque characteristics

25. Torque characteristics
 The torque characteristic of a motor is shown along with torque
characteristics of IC engine.
 For electric motor, a high torque is available at starting, which
is the rated torque of motor.
 The peak or rated power from a motor is obtained at base speed
(w b) when motor characteristics enter the constant power
region from constant torque region once voltage limit of power
supply is reached.
 The motor rated speed (w rated) is at end of the constant power
region. The IC engine peak power and torque occur at the same
speed.

26. Modes of operation-TOYOTA Prius

27. Commercial vehicles
 Toyota Prius
 Toyota Highlander
 Ford Escape
 Mercury Mariner
 Honda Insight
 Honda Civic HEV
 Honda Accord HEV

29. Challenges
 Time of battery changing is long
 Batteries are heavy (100kg extra weight consumes 2L/100km more)
 Batteries are expensive
 Low performance in hot or cold temperatures also may damage the
battery
 Very sensitive to overcharge/undercharge(Battery life reduces
dramatically)
 Contain toxic heavy metals, disposal issue

30. Advantages of a Hybrid Car
 Environment friendly
 Financial benefits
 Less dependence on fossil fuels
 Regenerative braking system
 Built from lighter materials

31. Disadvantages of a Hybrid car
 Less power
 Expensive
 Poor handling
 Higher maintenance cost

32. Conclusion
 Using the concept of Hybridization of cars results in better
efficiency and also saves a lot of fuel in today’s fuel
deficit world.
 A hybrid gives a solution to all the problems to some extent.
 One can surely conclude that this concept will follow with even
better efficiency & conservation rate