Hybrid Electric Vehicles

Abhilash RCB.EN.U4MEE10001

ContentsPart 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 pricesPollution and the resultant global warming

Noise in conventional vehiclesNeed for alternate power sources

EV, HEV - The solution?

HEV,EV?A traditional vehicle has sole propulsion by

ICE or diesel engineEV - 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 nowHigh Initial Cost- Many times that of conventional

vehiclesShort Driving Range- Range anxietyRecharging takes much longer time than

refueling gasoline-lack of charging infrastructureBattery pack takes space and weight of the

vehicle which otherwise is available to the peopleGrid loadICE + 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 architectureOperation Mode of Series

ArchitectureBattery 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 modeRegenerative braking mode

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 ArchitectureOperation 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 sizePossible 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 runs the car on the electric motor(s) only

CRUISING: ICE powerFULL 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 modelsToyota PriusToyota

HighlanderFord EscapeMercury

MarinerHonda InsightHonda Civic

HEVHonda Accord

HEV

Thank you