electric vehicles and urban transportations -...
TRANSCRIPT
Electric Vehicles and Urban transportations
Theodoros Kosmanis Alexander T.E.I. of Thessaloniki
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Pictures we want to forget!
[Source: http://www.reuters.com/]
[Source: http://www.thejakartapost.com/]
Beijing, January 29, 2013
East Jakarta
[Source: http://www.iav.com/]
Exhaust Gas Aftertreatment
[Source: http://en.wikipedia.org/]
Vehicle emissions
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What we dream of?
[Source: https://www.chinadialogue.net] [Source: https://www.sourcelondon.net]
GUTSi ZerO bus by Smith Electric Vehicles
EV charging station in Norway
[Source: http://www.planetizen.com]
[Source: http://www.tuvie.com]
CarGo concept vehicle
[Source: http://www.renewableenergymagazine.com/]
EV charging station Manchester, UK
• Electricity is used to move the wheels of a vehicle
• Powered by – One or more electric motors
• Source of electricity – Rechargeable batteries
– Fuel cells
– Photovoltaic (PV) solar cells
• Drivetrain: much more efficient than of ICEV
• Produce zero or near-zero tailpipe emissions
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What is electric vehicle?
• Electricity is used to move the wheels of a vehicle
• Powered by – One or more electric motors
• Source of electricity – Rechargeable batteries
– Fuel cells
– Photovoltaic (PV) solar cells
• Drivetrain: much more efficient than of ICEV
• Produce zero or near-zero tailpipe emissions
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What is electric vehicle?
● 1881 – The first electric vehicle (Frenchman Goustave Trouvé)
DC motor of 0.1 hp power Lead-acid batteries Vehicle and driver weight: ~160kg
● 1883-1911
– Competition between electricity and gasoline powered vehicles
● 1899
– Electric vehicle “La Jamais Contente” by Camille Jenatzy The first vehicle that passed 100km/h or 60mph (Ground speed world record)
● 1911
– Invention of starter motor for the internal combustion engine by F. C. Kettering
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Historical retrospection (I)
Not enough characteristics to attract people
● 1911-1960
– The electric vehicle was pushed aside due to:
● The obsolete battery technology
● Very low specific energy in contrast to the oil
● Oil as cheap and widely/easily available energy source
● Improvements in mass production techniques reduced the price of ICE vehicles
● Gasoline vehicle Henry T price: 260$ in 1925 - 850$ in 1909
● Invention of the electric starter motor for the ICE
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Historical retrospection (II)
● Since 1960: new interest for electric vehicles – Environmental concern including ICE vehicle emissions
– Depletion of oil reserves
– Dependence on oil production and transfer
– The autonomy and efficiency of batteries remain low
● Construction of electric vehicles was enforced through legislation – Law 94-413/1976 of U.S. Congress (Electric and Hybrid Vehicle Research, Development
and Demonstration Act of 1976)
– (California Air Resources Board) CARB
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Historical retrospection (III)
● EVs cannot compete ICEVs in range autonomy and performance
– Technological restrictions due to • Accumulators
• “Refueling” time and stations
• Infrastructure
– Not considered appropriate for long distances
– Ideal for small communities and in-city transportations
● New research trend: Hybrid electric vehicle
– First commercial: Toyota Prius, Honda Insight (1997)
– Nowadays: All types of vehicles (trucks, buses, motorcycles etc)
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Electric Vehicle restrictions
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Why electric motion?
EVs have been discontinued and HEVs are more popular
BUT
1. EVs of 1990s provided the technology that is now used in HEVs
2. New technologies may be developed that make EVs practical in the future
3. Fuel Cell vehicles (FCVs) are based on pure EV platforms
4. Still a large number of pure EVs in use today
● Accumulators (batteries)
– energy providers
● Electric motors
– drive the wheels
● Motor controllers
– power electronics
– control the energy flow to/from the motor
● DC/DC – DC/AC converters
– Convert the current and voltage levels to the desired ones
● Battery chargers
– (on board) responsible for charging the battery on the move or at station
● Power Management System (PMS) or Battery Management System (BMS)
– control the energy flow between battery and motor/electric loads
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Structural elements of an EV
● First years: conventional vehicle conversion – replacement of the ICE and the fuel tank by an electric motor and an
accumulator
– no other changes
● Disadvantages – Large weight
– Small flexibility
– Reduced performance
● Modern EVs – Innovative designs for the overall structure
– Exploitation of the flexibility offered by electric propulsion
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Electric vehicle architecture (I)
● Electric propulsion system – Electric motor (Μ) – Clutch (C) – Gear box (GB) – Differential (D)
● The clutch and the gear box can be replaced an automatic transmission system
● The clutch is used to connect or disconnect motor’s power from the driven wheels
● The gear box offers a set of gear ratios to adjust the speed-power (torque) profile to load’s demands
● The differential allows wheels of both sides to be driven at different speeds when the vehicle runs along a curved path.
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Electric vehicle architecture (II)
No transmission type (RF)
● The gear box and the clutch can be replaced by an electric motor (M) and a fixed gear system
● Electric motor – provides constant power along a wide range of speeds
● Structure’s advantages
– Mechanical transmission system • Size and weight reduction
– Simplifies the powertrain since no gear box is needed
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Electric vehicle architecture (III)
● Electric propulsion system – Electric motor (Μ) – Clutch (C) – Gear box (GB) – Differential (D)
● The clutch and the gear box can be replaced an automatic transmission system
● The clutch is used to connect or disconnect motor’s power from the driven wheels
● The gear box offers a set of gear ratios to adjust the speed-power (torque) profile to load’s demands
● The differential allows wheels of both sides to be driven at different speeds when the vehicle runs along a curved path.
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Electric vehicle architecture (IV)
No transmission type (front engine – front wheel, FF)
● The electric motor (M), the fixed gear system (FG) and the differential are further integrated into a unified structure – Both axles point at both driving wheels
● Structure’s advantages
– Mechanical transmission system • Further size and weight reduction
– Further simplification of the powertrain
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Electric vehicle architecture (V)
No differential type
● The mechanical transmission system is replaced by two electric motors (M)
● Electric motors – Each one drives one side wheel – Different input parameters (voltage, frequency) – different wheel speeds
along curved paths
● No need for differential
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Electric vehicle architecture (VI)
In wheel drive
(with gear set)
● The traction motors (M) are placed inside the wheels
● A thin gear set is placed inside the wheel also – Reduces motor speed
– Increases motor torque
– Inline arrangement of the input and output shaft
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Electric vehicle architecture (VII)
In wheel drive (without gear set)
● Complete removal of any mechanical gear ratio system between the electric motors and the wheels
● The rotor of each electric motor is directly connected to the wheel
● Speed control of the electric motor is equivalent to the speed control of the wheel and thus of the vehicle
● Disadvantage – A high torque electric motor is required for start and acceleration – High torque motor = larger motor
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Electric vehicle architecture (VIII)
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Electric vehicle systems
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EV energy storage system (ESS)
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EV energy sources
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EV energy sources
Electrochemical batteries (accumulators)
− High voltage, increased capacity
● Ultracapacitors, supercapacitors
● High-speed flywheels (mechanical energy storage system).
● Fuel cell technology
– Very promising for the future
– Chemical energy of a fuel is directly converted into electricity
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EV energy sources – Requirements
● Specific energy (high)
– Total energy available per unit mass (kWh/kg)
– Important for mileage (range) of the EV
● Specific power (high)
– Total power available per unit mass (kW/kg)
– Important for acceleration, uphill movement of the EV and regenerative braking
● Efficiency (high)
● Maintenance
● Safety
● Easy management
● Low cost
● Environmental adaptation and friendliness
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EV energy sources – Batteries
● Chemical energy to DC electric energy
● Part with the greatest cost, weight and volume
● Battery pack: battery cells tied together to provide required voltage/current
– Higher voltage = more power and larger battery packs
● Rechargeable: the chemical reaction and electric current can be reversed
– Recharged during regenerative braking or by means of a charger when the vehicle is stopped
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EV energy sources – Batteries
The battery of an EV plays a different role that the battery of an ICEV
Internal Combustion Engine Vehicles
● The primary purpose of the battery is to provide large electric current for a short time period to the starter during start up (starting or starter battery).
● After start up, electricity is supplied through alternator
Electric Vehicles
● The batteries provide DC electric current to the motor(s) for a large time period.
● Need for much more powerful batteries from every point of view.
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EV energy sources – Batteries
Ragone plot EV energy sources
[Source: Rodrigo Garcia-Valle, João A. Peças Lopes, (Eds.), Electric Vehicle Integration into Modern Power Networks. Springer Verlang, 2012. (ISBN 978-1-4614-0134-6)]
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EV Battery management system (BMS)
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Battery management system (I)
● keeps charging voltages and currents that are best for the batteries
● controls discharge and charge activities to optimize driving range
● monitors batteries
– State of Charge
– Temperature
– Other vital conditions
● warns the driver when an outside charging is enabled so the vehicle cannot start
● controls (sometimes) the motor/generator system
● may include an on-board charging system
– plug-in 110/220V power supply
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Battery management system (II)
● Tied into the instrument panel to keep the driver aware of several conditions
● Toyota RAV4-EV
– Combined gauge cluster
SoC meter
traction battery voltmeter
warning light
– Operation similar to that of an ICEV
Battery SoC instead of fuel level
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Battery management system (II)
● Tied into the instrument panel to keep the driver aware of several conditions
● Toyota RAV4-EV
– Combined gauge cluster
SoC meter
traction battery voltmeter
warning light
– Operation similar to that of an ICEV
Battery SoC instead of fuel level
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Battery management system (II)
● Tied into the instrument panel to keep the driver aware of several conditions
● Toyota RAV4-EV
– Combined gauge cluster
SoC meter
traction battery voltmeter
warning light
– Operation similar to that of an ICEV
Battery SoC instead of fuel level
Electric battery example
Nanophosphate® Energy Core Pack (23kWh)
● A123 AMP20 Energy Module
● Nominal voltage: 393V
● Nominal energy: 23kWh
● Battery Management Systems
● Electrical Distribution Module (EDM),
● Battery Control Module (BCM),
● Current Sense Module (CSM)
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Electric battery example
Nanophosphate® Energy Core Pack (23kWh)
● Extended Cycle Life
● Long battery life for more than a million micro-cycles or thousands of 100% DOD (depth of discharge) cycles
● Wide SOC range enables greater battery utilization
● Higher charge and discharge rates for better performance and efficiency
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EV Battery Charging System
“Refueling” the EV
● Onboard chargers – Advantage
• Battery recharging anywhere • (electrical outlet)
– Disadvantage • Added weight and bulk • Solution: Low power chargers that require long charge times
● Offboard chargers
– Advantage • High power chargers faster charging
– Disadvantage • charging only at specific locations
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Battery charging (I)
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Battery charging (II)
Fast chargers: charges an average battery pack in 30min or less
Charge levels
● Level 1: standard household electrical plug
– Usually portable
– Ratings up to 120 VAC and 15A
● Level 2: onboard charger
– Ratings up to 240 VAC and 60A
● Level 3: onboard charger
– Ratings greater than 240 VAC and 60A
– Fast chargers
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Battery charging (III)
Ways of connection to external source of electricity
● Conductive charging
– 110/220V recharging method
– AC (outlet) to DC (vehicle) voltage
– Conductive, metal-to-metal contact
– Onboard chargers
● Inductive charging
– 220VAC recharging system using magnetic principles
– Weatherproof paddle is inserted into vehicle’s charge port
– Magnetic coupling – AC current induced (transformer)
– AC/DC converter
– No metal-to-metal contact
● Wireless charging
– Through magnetic coupling with external coils (e.g. on the ground)
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Battery charging (IV)
● Wireless charging example (M. Paulus, “Wireless charging system for electric vehicles”, US
Department of Energy)
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Battery charging (V)
Inductive charger Conductive charger
EV battery chargers and their configuration
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Battery charging (VI)
Typical Li-ion cell charge profile
[Source: Rodrigo Garcia-Valle, João A. Peças Lopes, (Eds.), Electric Vehicle Integration into Modern Power Networks. Springer Verlang, 2012. (ISBN 978-1-4614-0134-6)]
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EV Propulsion System
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Electric propulsion system
● Electric motors
– Convert electric energy from battery to mechanical energy (propulsion)
– Reversed operation (generators) mechanical to electrical (battery charging during movement, braking)
– Types of electric motors
• DC electric motors
• AC electric motors
• SRM and PM BLDC motors
● Power converters
– Provide proper voltage/current to electric motors
● Electronic controllers
– Control the operation of the power converters
– 3 functional units (sensor, interface circuitry, processor)
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EV Electric Motors
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Electric motors - requirements
● Frequent starts and stops
● High rates of acceleration and deceleration
● Hill climbing
– High torque
– Low speed
● Cruising
– Low torque
– High speed
● Very wide speed range of operation
● Lubricated for life with limited need for maintenance
● High reliability
● As low cost as possible Bus BLDC motor
Electric motors - requirements
● Frequent starts and stops
● High rates of acceleration and deceleration
● Hill climbing
– High torque
– Low speed
● Cruising
– Low torque
– High speed
● Very wide speed range of operation
● Lubricated for life with limited need for maintenance
● High reliability
● As low cost as possible
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● No need for current conversion ● Quite reliable
BUT ● Often maintenance (low durability) due to
– Brushes and commutator May cause overheating Decrease in reliability
– Solution: Brushless DC motors Can not provide enough power to move the vehicle
● Available maximum torque is at zero speed and decreases with speed
● Hotter – requires appropriate cooling
● Only separately excited DC motor can provide regenerative braking with
appropriate controller
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DC Electric motors
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AC Electric motors (I)
● Require DC/AC current conversion
● Very reliable
● Lighter than a corresponding DC motor
● No need for particular maintenance due to
– Absence of brushes and commutator
– Only one moving part – the shaft
● Operate at higher voltage/lower current than DC motors with same power
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AC Electric motors (II)
● Torque output constant over a wide range of speeds
– Even acceleration
– Driving without the need of a transmission for different speeds
● Easily applicable regenerative breaking
● Disadvantage
– High cost of power electronics for DC/AC conversion and vice versa
– It is overcome with the evolution of electronics
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In-wheel motors
4200W @ 1200rpm 190mm x 90mm
Appropriately designed (Light – Small)
Mitsubishi 4WD EV (Lancer Evolution MIEV)
● Combines in-wheel motors with Li-ion batteries
● AC motors
– Hollow donut construction
– Rotor outside the stator
– Opposite of conventional designs
Less complex
Weight saving
Overcomes steering problems
● Characteristics
– 67hp (~50kW) of power
– 518 N·m of torque
– 1590kg of weight
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EV Electronic Controller
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Electronic controller
● Receives electric signals from sensors
– Speed, torque, flux etc.
– Control inputs from accelerator and brake pedals
● Input signals are processed (hardware and software)
● Control signals are produced towards
– Electronic power converter
• Motor speed and power adjustment
• Movement direction of the motor shaft
• Energy flow during braking (generator operation)
– Battery management system
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EV Power Converter
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Power converter
● DC/DC power converter
– DC electric motor is used (voltage adjustment)
– Voltage reduction to 12V to provide power
• 12V accessories (headlights, taillights, window, power steering pump etc.)
• Keeps the 12V auxiliary battery (emergency power source) charged
● DC/AC converter
– AC electric motor is used
• DC voltage conversion into 3-phase AC one
– Its type depends on the motor type
– Output voltage varies according to
• demands of the driver
• vehicle
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Regenerative braking (I)
Very important EV characteristic and difference from ICEVs
2-directional energy flow
● Battery to wheels (acceleration and cruise)
● Wheels to battery (braking)
– Slows vehicle
– Partially recharges battery
Motor acts as generator
● Controller gets the signal from brake
● Controls energy flow from motor/generator to battery through power converter (DC/DC or AC/DC)
● Controls the amount of regenerative and hydraulic braking
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Regenerative braking (II)
Increases EV’s range especially inside cities
Advantages
● May increase range by 25%
● Decreases break wear
● Reduces maintenance cost
Found on more expensive EVs and HEVs
Works better when the generator can spin quickly
● Cannot convert the whole difference in kinetic energy
● Very short time period
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Future trends
The future of the EV lies in the increase of its range and better operational control
● Batteries
– Construction based on nanotechnology
– Specific Power ~ 4000 kW/kg
– Charge rate less than 10min
– Environmentally friendly
● Fuel cells
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Example: Smith Electric Vehicles
Smith Electric Vehicles : design, manufacture and servicing of commercial electric vehicles
Example: Smith Electric Vehicles
● Smith Power™
● Integration scheme allowing the use of batteries of varying sizes from different manufacturers.
● State of the art lithium ion battery cell technology is used
● Smith’s current preferred partners: Valence and A123.
● Configures battery size per vehicle model and route requirements
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Example: Smith Electric Vehicles
● Smith Drive™
● Vehicle drive and control system for the management of auxiliary systems.
● Brushless permanent magnet motor
● Increased efficiency
● Minimum size and weight
● Integrated control protocol with Smith Power with common diagnostic interface.
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Example: Smith Electric Vehicles
● Smith Link™
● onboard system that monitors and transmits the vehicle’s vital statistics GPRS
● allows remote vehicle monitoring, diagnostics and reporting.
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Example: Fed Ex electric fleet
FedEx Express: the world’s largest express transportation company
● In 2008 created an electric commercial vehicle fleet in the United Kingdom
● Manufacturer: Modec (UK-based)
● Design specifically for commercial operation in urban environments
● Operation in the greater London metropolitan area
● Large, removable battery pack
● Travel up to seventy miles on one overnight charge
● Design focus on
● requirements of stop-start
● urban-duty cycles
● traffic conditions
Considered: “a smart, strategic investment for FedEx and supports ongoing efforts to foster the commercial development of viable new technologies that improve the environmental
performance of the transportation industry”
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Example
MOTOR Power: 70kw Horse Power: 102hp Torque: 221 ft.-lbs TRANSMISSION PRND (Park, Reverse, Neutral, Drive ) Clutchless Transmission BATTERY 80kWhr LI-Ion Cassette Standard On-Board Charger Standard PERFORMANCE CO2 Emissions Zero Maximum Speed (governed) 50 mph Range (up to) 100 miles
Example
BRAKING SYSTEM Front 4 Piston calipers - Disk Rear 10 inch Duo Servo Drum ABS Standard EBD Standard Regenerative Braking Standard Park Brake Hand Apply WHEELS + TIRES Wheels 17.5x6 steel-gray Tires 205/75R17.5 WEIGHT + CAPACITIES Gross Vehicle Weight Rating 12,122 Payload 5,100 Front Gross Axle Weight Rating 5,730 Rear Gross Axle Weight Rating 7,053
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Example
STEERING Electro-hydraulic power assisted Standard Turning circle (curb-to-curb) 36 ft. Steering wheel turns lock-to-lock 4.6 INTERIOR Electric windows Standard Electric mirror Standard I-Pack driver information display Standard IButton keyless ignition Standard Proximity mirrors Standard Visibility nearly 180 degrees
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Example: BYD electric bus
BYD's first all-electric bus series: K9
● Produced in China
● Dimensions: 12x2.55x3.2
● 31 passenger seats
● 4 In wheel electric motors
● Top speed: 100km/h
● Range: 249 km in urban conditions, 306 km in highway
● Charging
● Standard electric outlet: 6h
● Fast charging: 3h
● Energy consumption: ~100 kWh/96km
● Cost: 415 – 455 k€
● Version with solar panels on the roof for charging the batteries
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Electric mini bus examples
ΤYPE:EC - 61053KR PASSENGERS' SEATS: 12 ENGINE POWER/VOLTAGE: 5kW / 48V AUTONOMY:100km MAX. SPEED:40km/hour MAX. SLOPE: 20% BRAKES:HYDRAULIC DRUM BRAKES MINIMUM TURNING RADIUS (mm): 5.500mm DIMENSIONS (mm): 5.080x1.490x1.940
Electric mini bus examples: ZEUS
ΤYPE: EB - ZEUS PASSENGERS' SEATS: 34 ENGINE POWER: 30kW (60kW max.) AUTONOMY: 120km (lithium battery) MAX. SPEED: 45 - 50 km/hour BRAKES: DISC & DRUM BRAKES MINIMUM TURNING RADIUS (mm): 13.370mm DIMENSIONS (mm): 5.890x2.070x2.595 WEIGHT: 3.950kg AIR CONDITIONING: TROPICAL EV-25 (25.000btu/h) 73
Electric truck examples
SEATS: 2 + FLATBED ENGINE POWER: 5kW VOLTAGE: 48V BATTERIES: 8x6 (180Ah capacity) CHARGING TIME: 5 (90%) - 8 (100%) hours AUTONOMY: 70km (loaded) MAX. SPEED:30km/hour MAX. SLOPE: 20% DIMENSIONS (mm):3.475x1.390x1.200 FLATBED DIMENSIONS: 2.000x1.300 MAX. LOAD WEIGHT:1.000kg MAX. TOWING WEIGHT: 1.000kg
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Electric truck examples
SEATS: 2 + FLATBED ENGINE POWER:5kW VOLTAGE:72V BATTERIES: 12x6 (185Ah capacity) CHARGING TIME: 5 (90%) - 8 (100%) hours AUTONOMY:>80km (loaded) MAX. SPEED: 50km/hour MAX. SLOPE:20% DIMENSIONS (mm):3.600x1.500x2.100 FLATBED DIMENSIONS: 2.600x1.500 MAX. LOAD WEIGHT:1.500kg
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Example: Toyota i-Road electric three-wheeler
Electric personal mobility vehicle (PMV)
● Dimensions: 2,350 x 1,445 x 850 mm3
● 2 in line passenger seats
● 2 In wheel 2kW electric motors
● Top speed: 45km/h
● Range: 50 km in urban conditions
● Li-ion batteries
● Power: 5hp
Source: http://www.gizmag.com/
Toyota i-Road electric three-wheeler gets green light for early production October 5, 2013
Diagram of Toyota's Ha:mo RIDE system, providing flexible personal transport within city centers on a rental basis (Image: Toyota)
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Bibliography (I)
Books
● I. Husain, Electric and Hybrid Vehicles Design Fundamentals. CRC Press, 2003.
● M. Ehsani et al., Modern Electric, Hybrid Electric, and Fuel Cells Vehicles. CRC Press, 2005.
● J. Erjavec and J. Arias, Hybrid, Electric and Fuel Cell Vehicles. Thomson Delmar Learning, 2007.
● S. Leitman and B. Brant, Build your own Electric Vehicle. McGraw Hill, 2009.
● A. Fuhs, Hybrid Vehicles and the Future of Personal Transportation. CRC Press, 2009.
● Rodrigo Garcia-Valle, João A. Peças Lopes, (Eds.), Electric Vehicle Integration into Modern Power Networks. Springer Verlang, 2012. (ISBN 978-1-4614-0134-6)
Papers
● K. Jost (editor), “Global vehicles: Tokyo concepts”, SAE Automotive Engineering International, pp. 16-32, December 2007.
● S. Birch, “Powertrain: Prodrive leads new hybrid project”, SAE Automotive Engineering International, p. 38, January 2008.
● K. Jost (editor), “Global vehicles: On the cover”, SAE Automotive Engineering International, pp. 10-18, November 2008.
Presentations
● M. Paulus, “Wireless charging system for electric vehicles”, US Department of Energy, 2012.
Newspapers
● Automotive News Europe (www.autonewseurope.com)
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Bibliography (II)
Web sites
● http://www.anl.gov/ [Argonne National Laboratory – U.S. Department of Energy]
● http://www.hybridcars.com/electric-car [Hybrid cars]
● http://www.dieselnet.com/standards/eu/ld.php [Dieselnet - emission standards]
● http://www1.eere.energy.gov/vehiclesandfuels/avta/light_duty/fsev/index.html [Advanced Vehicle Activity Testing – U.S. Department of Energy]
● http://www.aerovironment.com/chargingsystems.asp [AeroVironment, Inc.]
● http://www.mitsubishi-motors.com/special/ev/index.html [Mitsubishi Motors]
● http://www.smithelectric.com/ [Smith Electric]
● http://news.van.fedex.com/fedex-express-modec-unveil-state-art-electric-vehicle [Fed Ex news]
● http://www.evi-usa.com/ [EVI automotive]
● http://ev.tfgm.com/index.html [Greater Manchester Electric Vehicle Scheme]
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Thank you for your attention
Dr. Theodoros Kosmanis Alexander TEI of Thessaloniki e-mail: [email protected]
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