1. Hybrid Electric Vehicles

2. Contents Part I: Current transportation scenario
Part II: EV & why that is not the solution now
Part III: Concept of hybridization
Part IV: Architectures of Hybrids
Part V: Commercial models

3. Part I: Current transportation scenario
Over dependence on petrol/diesel-it’s depletion
Rising petrol/diesel prices
Pollution and the resultant global warming
Noise in conventional vehicles
Need for alternate power sources
EV, HEV - The solution?

4. HEV,EV?
A traditional vehicle has sole propulsion by ICE or diesel engine
EV - Electric Vehicle, battery (or ultra capacitor, fly wheels) operated only. Sole propulsion by electric motor
An HEV (Hybrid Electric Vehicle) is a vehicle which involves multiple sources of propulsions

5. Part II: EV & why that is not the solution now
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
Grid load
ICE + Electric motor = Propulsion

6. Part III: 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
Modes of operation

7. Part IV: Architectures of Hybrids
According to the method the energy sources are arranged
Parallel HEV: Multiple propulsion sources can be combined, or drive the vehicle alone with one of the energy sources
Series HEV: Sole propulsion by electric motor, but the electric energy comes from another on board energy source, such as ICE
Power-split hybrid: Can work both as a series & parallel type hybrid

9. Series architecture Operation Mode of Series Architecture
Battery alone mode: engine is off, vehicle is powered by the battery only
Engine alone mode: power from ICE/G
Combined mode: both ICE/G set and battery provides power to the traction motor
Power split mode: ICE/G power split to drive the vehicle and charge the battery
Stationary charging mode
Regenerative braking mode

10. Advantages of Series Architecture
ICE operation can be optimized, and ICE itself can be redesigned to satisfy the needs
Smaller engine possible
High speed engine possible
Single gear box. No transmission needed. Multiple motors or wheel motors are possible
Simple control strategy
Disadvantages of Series Architecture
Energy converter twice (ICE/G then Motor), plus battery
Additional weight/cost due to increased components
Traction motor, generator, ICE are full sized to meet the vehicle performance needs

11. Parallel Architecture
Operation Mode of Parallel Architecture
Motor alone mode: engine is off, vehicle is powered by the battery/motor only
Engine alone mode: ICE drive the vehicle alone
Combined mode: both ICE and motor provide power to drive the vehicle
Power split mode: ICE power split to drive the vehicle and charge the battery
Stationary charging mode
Regenerative braking mode (include hybrid braking mode)

12. Advantages of Parallel Architecture
ICE operation can be optimized, with motor assist or share the power from the ICE
Flexible in configurations and gives room for optimization of fuel economy and emissions
Reduced engine size
Possible plug-in hybrid for further improved fuel economy and emission reduction
Disadvantage of Parallel Architecture
Complicated control strategy
Complex transmission

13. TOYOTA Prius (Power-split) architecture

14. Modes of operation-TOYOTA Prius

15. Modes of operation-TOYOTA Prius
At start-off/low-speeds, HSD runs the car on the electric motor(s) only
CRUISING: ICE power
FULL ACCELERATION: ICE power + battery power
CRUISING: ICE power + battery charging
DECELERATION, BRAKING: kinetic energy recuperation for battery charging

16. Key advantages of HEVs Optimize the fuel economy
– Optimize the operating point of ICE
– Stop the ICE if not needed (ultra low speed and stops)
– Recover the kinetic energy at braking
– Reduce the size (hp and volume) of ICE
Reduce emissions
– Minimize the emissions when ICE is optimized in operation
– Stop the ICE when it’s not needed
– Reduced size of ICE means less emissions

17. Quiet Operation
– Ultra low noise at low speed because ICE is stopped
– Quiet motor, motor is stopped when vehicle comes to a stop, with engine already stopped
– Reduced maintenance because ICE operation is
optimized, less hazardous material, fewer tune ups, longer life cycle of ICE
– Fewer spark-plug changes
– Fewer oil changes
– Fewer fuel filters, antifreeze, radiator flushes or water
pumps
– Fewer exhaust repairs or muffler changes

18. Key Concerns of HEVs High initial cost
– Increased components such as battery, electric machines, motor controller, etc.
Reliability concern
– Increased components, especially power system, electronics, sensors
Warranty issues
– Issues on major electric components
– Dealership and repair shop not familiar with new components
Safety: high voltage system employed in HEV

19. Part V: Commercial models
Toyota Prius
Toyota Highlander
Ford Escape
Mercury Mariner
Honda Insight
Honda Civic HEV
Honda Accord HEV

20. Thank you