Download Hybrid Electric Vehicles

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
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?
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
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
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
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
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
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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
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)
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
TOYOTA Prius (Power-split) architecture
Modes of operation-TOYOTA Prius
Modes of operation-TOYOTA Prius
 At start-off/low-speeds, HSD
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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
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
 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
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
Part V: Commercial models
 Toyota Prius
 Toyota Highlander
 Ford Escape
 Mercury Mariner
 Honda Insight
 Honda Civic HEV
 Honda Accord HEV