electrification of power-train systems

7/27/2019 Electrification of Power-Train Systems

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ELECTRIFICATION OF POWER-TRAIN SYSTEMS


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Presentation Outline

Automotive Industry Indian Scenario

Need of Electrification of Automobiles Overview of promising pathways

Electric Drive Vehicles

Why EVs?

Why HEVs?

Types of Hybrid Electric Vehicles

Why Plug-in Hybrids?

Whats a Plug-in Hybrid Electric Vehicle (PHEV)?

PHEV Benefits

Types of Electric Drives

Types of Batteries

Key Benefits and Challenges of PHEVs

PHEV Prototypes

Summary


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Automotive Industry Indian Scenario

o The Indian automotive industry after de-licensing in July, 1991has grown at a spectacular rate on an average of 17% for thelast five years.

o The level of production of vehicles from 2 million in 1991 to9.7 million in 2006 ( i.e., 2.37% of world production of 66.46million vehicles).

o As per the Asian development bank (ADB) study, vehiclepopulation growth in India increases by 6.7 times by year2025.

o India imports 72% of its petroleum which is likely to go up to92% by the year 2020.

o In Asia, as per the new study backed by the ADB, emissions ofCO2 from the transport sector will triple over the next 25years.

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Transportation Triple Threat

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o Vehicle emissions like CO, HC, NOx, PM, VOC, SOx, etc.

o Petroleum use and greenhouse gas emissions are increasing

globally by about 2% per year due to steady growth in landand air, passenger and freight transportation demand.

o There ha been regular dumping of 30 billion tonnes of carbondioxide into the atmosphere by all the nations every year.

o If the oil discovery and consumption follow current trends, the

world oil resources will be depleted by 2038.


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o Increasing automobiles

o Declining oil reserves

o Increasing oil Prices

o Increasing greenhouse gas emissions

o Global warming

o Global Climate Change

o Environmental Pollution

o Ozone Depletion

o Growth in global economies

o Political instability

o Stringent Emission regulations

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Need of Electrification of Automobiles


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What is the Solution?

Improve the existing power system efficiency

Alternate fuels

Alternate power systems like electric Drive vehicles

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Overview of promising pathways

Advanced engine technologies

o DI technologies

o Downsizing and turbo-charging

o Additional variabilities

o HCCI

o Aftertreatment systems

Power-trainso Electric vehicles

o Hybrids

o Plug-in-Hybrids

o Fuel cell vehicles

Fuels

o Alcohol fuels

o Biodiesel

o Hydrogen

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Gasoline Direct Injection

o

Allows higher compression ratioo Reduced fuel consumption up to 15 %

o Up to 5 % higher torque

o Overall air/fuel ratio lean

o Increased fuel economy

Downsizing and Turbo-charging

o Operating regime shifted to more efficient areas

o Turbo-charging used

Additional Variabilitieso Variable valve Timing

o Variable Valve Lift

o Camless Engine

o Variable Compression Ratio Engine8


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Homogeneous Charge Compression Ignition(HCCI)

o

Low NOx Emissionso Low PM Emissions

o High Engine Efficiency

o Up to 5 % higher torque

Aftertreatment systemso Closed loop Catalytic converters

o Secondary Air Injection

o Selective Catalyst Reaction

o Thermal Reactors

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Electrification of AutomobilesFrom Conventional Power-train to Fuel Cell Vehicles

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Concept of Electric Drive Vehicle

o Electric Drive Vehicle is a road vehicle based on modernelectric propulsion consisting of electric machines, power

electronic converters, electric energy sources and storagedevices, and electronic controllers.

o It is a broad concept, including Battery Electric Vehicle,Hybrid Electric Vehicle, Plug-in Hybrid Electric Vehicle, FuelCell Electric Vehicle, Solar Vehicle, etc.

o Regenerative breaking is possible.

o A new system for our societys clean and efficient roadtransportation.

o An intelligent system which can be integrated with modern

transportation networks.

o Design involves the integration of art and engineering.

o More advancements are to be done to make them affordable.

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Three major components and interconnections

o Propulsion System: Generates the necessary power tothe wheels. Includes transmission and energy managementsystem.

o Energy source: Consists of energy sources like fossil fuel,battery, fuel cells, or generator

o Auxiliary power system: Supplies power to auxiliaries

like A.C., lightning system, etc.

Propulsion

system

Energy

Source

Auxiliary

Power

Wheels

Electric Drive Vehicle Composition

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Battery Electric Vehicle (BEV)

o Large battery for long rangeo Advanced control electronics

o Large electric motor

o BEV has no method of charging the battery from liquid fuels

o

It has to be plugged into a power source

Hybrid Electric Vehicle (HEV)

o Has very small battery pack

o Has both an internal combustion motor and electric motor

o Battery only charges from IC engine

o Cannot be plugged into grid



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Plug-in Hybrid Electric Vehicle (PHEV)

o Has both an internal combustion motor and electric motor

o Has larger battery pack with longer EV range

o Has to be plugged into grid

Hydrogen Fuel Cell Vehicle (FCV)

o On-board hydrogen fuel cell generates electricity

o

Has very small battery or ultra capacitorso Has large electric motor

o FCVs have many unsolved problems



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High fuel cell cost

Lack of infrastructure

Dependence on fossil

fuel

complex

Limitations of battery

Short range (100-200km)

Charging facilitiesMajor issues

Zero emission

Independence on fossil oil

High energy efficiency

Under development (futuretrend)

Low emission

Higher fuel economy

Commercially available

Zero emission

Independence on fossil oil

Commercially availableCharacteristics

Hydrogen

Methanol or gasoline

ethanol

Gasoline stations

Electric grid chargingfacilities (optional for

plug-in hybrid)

Electric grid charging

facilitiesEnergy sourceandinfrastructure

Fuel cellsBattery

Ultracapacitor

ICE generating unit

Battery

ultracapacitor

Energy system

Electric motor drivesElectric motor drives

ICE

Electric motor drivesPropulsion

FCEVHEVBEVTypes of EVs

Comparison of BEV, HEV, and FCEV

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o Reduced greenhouse gas emissions.

o

Reduced the major causes of smog.o Substantially eliminates Ozone depletion.

o Reduce noise pollution.

o Carbon dioxide in air which is linked to global warming, would

cut in half.o Waste oil dumping would decrease, because EVs do not

require crankcase oil.

o Reduction in foreign oil consumption enhances national

security.o The power curve of electric motors is better suited to variable

speeds and can provide substantially greater torque at lowspeeds compared with internal-combustion engines.

o Reduced wear on brakes from the regenerative braking system

use.

Why EVs?


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Overall Efficiency of ICE Vehicle

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ICE Vehicle Max. Min.

Crude oil Refinery (Petroleum) 90 85

Distribution to fuel tank 99 95

Engine 22 20

Transmission/ Axle & Wheels 98 95

Overall Efficiency

(Well-to Wheel Efficiency)

19 15


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Tank to Wheel Efficiency of ICE Vehicle


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Electric Vehicle Max. Min.

Crude oil Refinery (Petroleum) 97 95

Electricity Generation 40 33

Transmission to Wall Outlet 92 90

Battery (Lead Acid) & Battery Charger 75&90 75&85

Motor / Controller 85 80

Transmission / Axle & Wheels 98 95

Overall Efficiency

(Well-to Wheel Efficiency)

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Overall Efficiency of Electric Vehicle


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o Engine is OFF when vehicle is not moving saves motor fuel.

o Internal Combustion engine can be sized for average, NOTpeak power load saves fuel and produces less emissions(Eliminates idling losses).

o Regenerative braking returns energy, normally lost as heat toenergy storage (Captures 50% of braking losses).

o Precise computer control utilizes each conversion device in itsmost efficient zone of operation.

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How hybrids are more efficient and cleaner?


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Types of Hybrid Electric Vehicles

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Series Hybrid Electric Vehicle

o Series hybrids use their internal combustion engines only togenerate electricity.

o Traction power comes entirely from one or more electricmotors.

o The engine in a conventional vehicle is forced to operateinefficiently in order to satisfy varying power demands of stop-and-go driving, series hybrids perform at their best in such

conditions.


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Parallel Hybrid Electric Vehicle

o Parallel hybrids use both an internal combustion engine and anelectric motor to drive the wheels.

o The motor serves double duty, also acting as a generator to

charge the batteries during braking or when the battery pack isdepleted beyond a predetermined amount.

o The engine is connected directly to the wheels, it eliminatesthe inefficiency of converting mechanical power to electricityand back, which makes these hybrids quite efficient on thehighway.

i ll l ( li ) b id l i hi l


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Series - Parallel (Power Split) Hybrid Electric Vehicle

o Power-split hybrids channel a fraction of the power from theirinternal combustion engine to the wheels; the rest is used toturn a generator, which charges the vehicles modestly sizedbattery.

o Stored energy in the battery is used to operate an electricmotor, which in conjunction with the engine drives the wheels.

o The Toyota Prius uses this general configuration.


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o Power Split drive-train merges the advantages andcomplications of the parallel and series drive-trains.

o By combining the two designs, the engine can both drive thewheels directly (as in the parallel drive-train) and beeffectively disconnected from the wheels so that only theelectric motor powers the wheels (as in the series drive-train).

o At lower speeds it operates more as a series vehicle, while at

high speeds, where the series drive-train is less efficient, theengine takes over and energy loss is minimized.

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Series - Parallel Hybrid Over Parallel Hybrid


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Current Hybrids

Toyota PriusToyota Camry Toyota Highlander Honda Insight

Lexus RX400h Lexus GS450hHonda Civic Honda Accord

Saturn Vue Chevy SilveradoFord Escape

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Hybrid Electric Vehicles Two Main Types


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Why Plug-in Hybrids?

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o Electric vehicles (EVs) are more energy efficient and have zerotail pipe emission in urban situations. However, they have notbeen successful because of limited range and lack ofrecharging infrastructure.

o Hybrid electric vehicles (HEVs) do offer improved fueleconomy, low emissions and take the advantage of existingfuel infrastructure, but, still they depend entirely on petroleum.

o Hydrogen and fuel cell technology has advanced rapidly, butstill facing significant improvement for effective cost,infrastructure and technical challenges that could limit marketpenetration within next 15-20 years.

o One clear solution is that there is a need to develop an electricvehicle to meet the function-specific, addition to city driving aswell as weekend and holiday outing of longer distances.

o Transportation sector nearly 100% petroleum dependent andaccounts for two-thirds of total petroleum consumption.


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Whats a Plug-in Hybrid Electric Vehicle (PHEV)?

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o A Plug-in hybrid electric vehicle is a hybrid vehicle with large

batteries that can be charged by connecting a plug to anelectric al power source.

o Has both IC engine & electric motor and battery.

o Still runs on petroleum only, but much (up to 50%) more

efficient.o Engine does not idle.

o Recovers braking energy.

o Smaller capacity engine.

o Reduces emissions and reliance on (imported) oil.

o Reduces urban pollution.

o Much lower running costs (but high battery costs).


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Plug-in Hybrid Electric Vehicle Components

o Internal Combustion Engine

o

Motor / Generatoro Power Electronics

o Battery Pack

o Battery Chargers

o Fuel Tank

Major Components


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o Unlike the hybrids one sees on the road today, plug-in hybridsuse relatively small internal combustion engines and relativelylarge electric motors and battery packs. As a result, they canhave impressive all-electric ranges.

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Difference between Hybrids and Plug-In Hybrids


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PHEVs: Greenhouse Gas Emissions


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1000100000

5000001000000

Midsize HEV20

Midsize HEV0

Conventional

0

1000000

2000000

3000000

4000000

5000000

6000000

PHEVs: No. of Vehicles Vs Greenhouse Gas Emissions

Number of Vehicles

Tonsof

CO2


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PHEVs: Annual Petroleum Consumption


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PHEVs: No. of Vehicles Vs Petroleum Consumption

A PHEV20 consumes 30% less petroleum36

Mids ize HEV20

Midsize HEV0

Conventional

-

50,000,000

100,000,000

150,000,000

200,000,000

250,000,000

300,000,000

350,000,000

400,000,000

450,000,000

1000100000

5000001000000Number of Vehicles

Gallons


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A Second Way of Looking at Fuel Consumption

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PHEV Benefits

o PHEVs are two or three times more fuel efficient thanconventional vehicles.

o Reduced fuel consumption and tailpipe emissions.

o Cleaner electric energy through advances in natural gas and

coal gasification.

o Any decentralized renewable energy based power can beused.

o Recovered energy from regenerative braking minimizes

energy loss.

o Unchanged fuel filling station infrastructure.

o Grid connection potential.

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PHEV Benefits

o Home based battery recharging at a fraction of the cost ofpetroleum equivalent.

o Pure zero emission capability.

o Lower fueling costs compared to hybrid electric vehicles.

o

Possible use of secondary markets to get used batteries andreduce waste.

o PHEVs can run on alternative fuels and thus can reduce thedependency on fossil fuels.

o Produce fewer emissions in traffic and when operating at lowspeeds.

o Even in the case where you forget to plug a PHEV in, the IC

engine will simply take over when the battery is depleted.

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T f El i D i


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Types of Electric Drives

DC Electric Motors

o DC from battery to motor.

o Uses DC motor controller to vary speed.

o Brushed DC motors are less efficient.

AC Electric Motoro Uses an inverter to convert DC into AC and control motor

speed.

o AC induction motors are extremely reliable and efficient andform the majority of industrial electric motors.

o Modern variable speed AC drives are also compact andreliable with no moving parts.


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Advantages of AC Electric Motors

o Most modern cars use AC electric motors because if theirgreater efficiency.

o Inverter is part of the drive and can be used to supply grid.

o AC inverter drives can use regenerative braking to extendrange.

o Modern variable speed AC drives do not need gearboxesfurther increasing efficiency.

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Types of Batteries


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Types of Batteries

Lead Acid

o Energy Density 45 Whr/kg

o Cycle Life 500 cycleso Cheap but heavy, low cycle life

Nickel Metal Hydride

o Energy Density 65 Whr/kg

o Cycle Life 1000 cycles

o More expensive and lighter

o Reliable

o Moderate power

o Reasonable size and weight

Lithium Iono Energy Density 154 Whr/kg

o Cycle Life 1000 cycles

o Very expensive but light and energy dense

o 2-3 times the power of Ni-MH

Why Lithium Ion Batteries


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Why Lithium Ion Batteries

o Potential for 30% reduction in system volume than Ni-MH.

o Potential for substantially lower, 50% less weight than Ni-MH.

o Li-Ion requires fewer cells for the same system voltage.

K B fit f Pl i H b id


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Key Benefits of a Plug-in Hybrids

By plugging it in

CONSUMER BENEFITS

NATIONAL BENEFITS

Homerecharging

convenience

Fuel

flexibility

Fewer

fill-ups

Lowerfuel

costs

Energydiversity

Better

utilization ofgeneration

capacity

Less airpollution

Less CO2

emissions Lesspetroleum

use

Vehicle-to-grid(V2G) potential

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K Ch ll f Pl i H b id


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Key Challenges of a Plug-in Hybrids

By plugging it in

COST BENEFIT ANALYSIS

Battery Size

& Weight

Vehicle

CostComponent

Packaging

Recharge

locations Battery

Life

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PHEV Prototypes

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I d t I t t i PHEV


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Industry Interest in PHEVsAnnounced Programmes by Major OEMs

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S


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Summary

o PHEVs are a key technology in the portfolio of options toreduce petroleum consumption.

o They also provide significant consumer and national benefits.

o Precommerical PHEV prototypes are on the road today.

o There has been a surge in community, industry and politicalsupport for PHEVs.

o The key barriers to commercial PHEVs are battery life,packaging and cost.


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electrification of power-train systems

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