Transcript Automotive Hybrid Experience Applied to Electric Aircraft Design by Marc W. Wiseman, Ph.D., Divisional Product Group Director, Advanced Technology and James C.

Automotive Hybrid Experience
Applied to Electric Aircraft Design
by
Marc W. Wiseman, Ph.D., Divisional Product Group Director, Advanced Technology
and James C. Paul, P.E., Senior Engineer and Business Development Manager
Ricardo, Inc.
NASA PAV
Concept
Shadow 200 UAV
www.cafefoundation.org
http://www.designation-systems.net/dusrm/app2/q-7.html
Electric Aircraft Symposium
Westin Hotel, Millbrae, California
23 May 2007
© Ricardo plc 2007
CONFIDENTIAL - Internal Use Only
Automotive Hybrid Experience Applied to Electric Aircraft Design
The auto industry has evaluated a wide range of hybrid schemes
Electrical
Machines
Thesis
Power
Transmission
Energy
Storage
www.evworld.com/press/sandia_lithium-ion.jpg
 The automotive industry has made significant progress in the area of electric
vehicle (EV) and hybrid-electric vehicle (HEV) drive systems.
 This experience can be leveraged to support development of electric and
hybrid-electric PAVs and UAVs.
NASA PAV
Concept
Shadow 200 UAV
 Energy storage, on-board power generation, vehicle modeling and
integration, electric machines, and controls/power electronics will be
discussed.
 Possible integration of these technologies into future aircraft designs will be
explored.
© Ricardo plc 2007
CONFIDENTIAL - Internal Use Only
Automotive Hybrid Experience Applied to Electric Aircraft Design
Company Overview
© Ricardo plc 2007
CONFIDENTIAL - Internal Use Only
Ricardo has been involved in hybrid vehicle development since 1999:
1. Proprietary programs for OEMs, component suppliers,
government agencies, military.
2. Ricardo internal R&D programs
HyTrans
Micro Hybrid
GVWs have ranged from 3.5 to 25 tons.
i-MoGen
Ford Escape HEV
Mild Hybrid
© Ricardo plc 2007
US Government Advanced Hybrid Vehicles
Full Hybrid
Hybrid Refuse Truck
Efficient-C
Optimum Efficiency
Military/Off-road
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Projects have spanned the full range of hybridization,
from “micro” to “full”
© Ricardo plc 2007
Micro
Mild
Full
Commercial
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© Ricardo plc 2007
Ricardo’s hybrid experience includes over 120 dedicated
development engineers & consultants
 Program management
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Current technology analysis
Market characteristic assessment
Opportunities assessment
Technical trend assessment
Program planning business case development
Program support & guidance
 Powertrain and Vehicle
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Production design and release
Vehicle engineering & system simulation
Engine and transmission design and development for hybrids
Prototype and pre-production build
 Controls and Electronics
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System simulation
Control strategy development
Embedded software development
Software tools
Hardware-in-the-loop application
 Electric Machines,
Power Electronics and
Energy Storage
– Motor development
– Electronic hardware (including power electronics) development and
validation
– Energy storage modelling, test and validation
Ricardo is experienced in developing corporate strategies for hybrid vehicles
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Ricardo has been actively engaged in advanced energy storage
systems and integration into hybrids for over 6 years.
 Requirements definition and cost/benefit analyses for EVs, HEVs and
PHEVs
 Mechanical design for vibration, shock and crash
 Pack design for cost, assembly and manufacture (DFx)
 Thermal design, analysis, development and validation
 Simulation and test, validation of battery system
 Control algorithm and software development for SOC/SOH
 Battery Management System (BMS) hardware design and validation
 Safety system integration, FMEA, and Hazard Analysis
 Supply chain management of subsystems
© Ricardo plc 2007
 Prototype manufacturing, validation and launch support
 Ricardo currently studying market potential for establishing a
Center of Excellence for Energy Storage development in Michigan
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Status of Automotive Hybrid Technology
Toyota Prius
Honda Civic
Ford Escape
Saturn Vue
Nissan Altima
 Five OEMs have hybrid products on the market. Many offer more than 1 vehicle and
most are working on at least their second generation of hybrid technology.
 Hybrids vehicles are low volume – key focus is on production quality of hybrid
components to avoid warranty costs. Production targets include:
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Design for less than 100 ppm failures in vehicle (i.e zero failure).
Design for 150k miles / 10 year life (equates to over 7500 hrs of operation time)
Robust to significant vibration and shock forces.
Robust to thermal temperature extremes.
 NiMH batteries are proving to have good cycle life and good calendar life.
© Ricardo plc 2007
 Lithium ion technology is being actively developed for next generation hybrid
batteries.
 Good understanding is being gained of potential operating failure modes for hybrid
systems and mitigation strategies.
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Ricardo’s Current Aerospace Activities
Focus on Unmanned
Aerial Vehicles
Aviation Week & Space Technology April 2, 2007
© Ricardo plc 2007
 Wide range of applications, 1hp to 1000hp
– “Backpack” engine for suit cooling/local power
– “Powerpack” handheld genset engine
– Several UAV engine concepts, including High
Altitude
– UAV heavy fuel engine demonstrator
– Helicopter powerplant concept for extended
range
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Ricardo’s Current Aerospace Activities
UAVs span a wide size range, including sizes appropriate for PAVs
• Military applications
are a primary driver for
the UAV industry.
© Ricardo plc 2007
• Current goals are:
1.
Increased Endurance
2.
Reduced Noise
3.
Operate on Available
Fuels
4.
Increased Payload
Capacity
5.
Reduced Maintenance
6.
Improved Durability
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Approach to Electric/Hybrid Aircraft Design
Full-Throttle Power Available
Perform mission requirement/energy
requirements trade-off studies using:
© Ricardo plc 2007


Classical analysis (spreadsheets)
Computer simulation
Available libraries allow simulation of a wide range of power
system designs to facilitate selection and sizing of components.
MSC.EASY5
– MSC.EASY5
Ricardo Powertrain Library
Ricardo Engine Library
Ricardo Fuel Cell Library
Ricardo Electric Drive Library
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Approach to Electric/Hybrid Aircraft Design
Backside of power curve: if
speed is decreased, power
must be added to hold altitude
Design Propulsion System Based on
Minimum Energy Mission Approach (takeoff,
dash, cruise)
Power Required Curve
 Best Endurance Speed = Speed at
Minimum Power (maximum time in
air)
Range Speed = Speed at
 Best
Which the Ratio HP/V is a Minimum
(the speed giving the greatest ratio
of velocity to horsepower required).
 Assumes the thrust specific fuel
consumption (lb/THP-hr) is
essentially constant over the low HP
range.
Speeds for Best Range and Endurance for Propeller-Driven Aircraft
© Ricardo plc 2007
From: Dommasch Airplane Aerodynamics, Fourth Edition, Page 302
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Approach to Electric/Hybrid Aircraft Design
TOOLS
– Matlab Simulink, EASY5
Ricardo Powertrain Library for Simulink
V-SIM (IPT)
Ricardo Engine Simulation Libraries
Drive Cycle Simulation of Mild Hybrid Diesel-Electric Pickup Truck
Motor-generator
mechanical power
Motor-Generator Mechanical Power
2E+4
1.5E+4
Power [W]

1E+4
5E+3
0
-5E+3
-1E+4
0
CAPABILITIES
 Duty Cycle Simulation (fuel consumption and
emissions)
 Performance Simulation (Climb, Dash, Top Speed)
 Co-simulation with WAVE, FLOWMASTER, etc.
100
200
300
400
500
300
400
500
Time [s]
Engine Torque
250
200
Torque [N.m]

150
100
50
0
-50
0
100
200
Time [s]
Engine torque
Model: ParallelHybrid, Runid: simulation, Case: 1, Display: 7. 06-FEB-2003, 10:38:34
i-MoGen Control System
Sensor
Vacuum
• 14 Micro Controllers / Computers added
WABCO
Brake Assist
Battery state of charge
Sensors
(Many)
Sensors
(Many)
CANTRACK NEW BOSCH
VDU
ECU
Sensors
Voltage
VALEO
DC/DC conv
VALEO
FMED CU
OPEL
hE-PAS
Sensors
V + Amp
VALEO
Battery Man
Sensors
Thermal
VALEO
HVAC
present on car
OPEL
ABS
State [0-1]
• + 2 temporary calibration tools
Average fuel economy
Drive Cycle Simulation of Mild Hybrid Diesel-Electric Pickup Truck
0.8 Battery State of Charge
• 6 smart actuators or ancillaries
present on car
0.6
0.4
0.2
CAN
0
0
100
200
300
400
500
Time [s]
K-Line
PWM
VEMPS
Smart
VNT actuator
Smart
Fans
Smart
EGR actuator
Smart
Actuators
Smart
Throt’ actuator
(60Mb project code)
Sensor
Doors
Sensor
Brake Pedal
Laptop with
INCA Calibration
Tool
Sensor
Vehicle Speed
Sensor
Bonnet
(temporary)
Sensor
Clutch Pedal
Sensor
Voltages
CANALISER
1.5E+4
1E+4
5E+3
0
(temporary)
-5E+3
-1E+4
0
© Ricardo plc 2007
Set point versus actual speed
Battery power
2E+4
Analogue
Power [W]
Smart
Water Pump
Battery Power
2.5E+4
100
200
300
400
500
Time [s]
Vehicle Control System Development
Model: ParallelHybrid, Runid: simulation, Case: 1, Display: 6. 06-FEB-2003, 10:38:34
Drive Cycle Simulation of a Light commercial Truck
CONFIDENTIAL - Internal Use Only 13
One challenge for Electric aircraft is the weight of the energy
storage system.
For the following example, Lithium-Ion Batteries were Selected as Being Representative of the
Best Currently-Available Technologies for Energy and Power Density
Example Operating Characteristics for UAV
Target Weight
300 lbs [136 kg]
Typical cruise power
6 HP [4.5 kW]
Typical take off power
24 HP [18 kW]
Estimated take off energy
Estimated cruise energy
3 kWh
4.5kWh per hour of flight time.
Estimated Automotive Li-ion Battery Characteristics
© Ricardo plc 2007
Li –ion energy density
Li-ion max power density
Li-ion cont power density
Current estimated battery life
80 – 120 Wh / kg
1300 – 1600 W / kg
800 – 1000 W / kg
5000 flights
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Battery weight remains a challenge which limits flight time
Effect of Battery Cell Weight on Flight time
700
Battery weight (lbs)
600
500
Calculations based on
a 300 lb UAV
400
UAV weight !!!
300
The battery pack alone would
be 300 lbs for a 3 hr flight
time !!
200
100
0
0
1
2
3
4
5
6
7
© Ricardo plc 2007
Flight time (hrs)
A holistic approach is needed to improve flight time by finding ways to reduce takeoff and cruise power,
take weight out of all components.
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How can performance be improved if energy storage remains a
limiting factor?
1.
Reduce drag, CD

© Ricardo plc 2007

Traditional aircraft design approaches
have included trade-offs between
efficiency and performance with focus
on performance.
2.
Reduce weight, W
3.
Improve efficiency, CL/CD
4.
Change mission profile (e.g. HP vs time history,
improved take-off profiles)
5.
On-board power generation (e.g. solar cells)
6.
Improved energy storage systems
Electric aircraft will include similar
trade-off studies, but the focus will be
on minimizing energy use.
http://www.pvresources.com/en/helios.php
AeroVironment Helios Aircraft with
Solar Panels on Wings
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To meet goal of 8hr+ flight time, efficiency improvements and
alternative power sources are needed.
Solar Energy Benefit to Flight time
5
4.5
Solar Energy (kW)
4
Solar cells alone are not
optimum solution
3.5
3
Effort is required to
reduce cruise power
2.5
2
1.5
100 lb Battery Pack
1
150 lb Battery Pack
0.5
© Ricardo plc 2007
0
0.00
100lb Battery Pack - 50% lower cruise
power
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
20.00
Flight Time (hrs)
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Conclusions
 Automotive engineering practice is providing high quality, robust and long life electric
motors, electronics and battery systems.
 Hybrid road vehicle technology is developing at a rapid pace with particular progress
being made in the areas of 1) equipment costs (including manufacturing methods and
economies of scale), 2) operational failure modes are well understood and mitigation
strategies can be deployed, and 3) weight optimization methods.
 Current battery technology presents a challenge for achieving weight targets.
 Detailed analysis and a holistic approach to UAV/PAV design is required to meet
mission requirements. Modeling tools are available to assist in configuration
assessment and component sizing.
© Ricardo plc 2007
 Note possible technology development opportunity: DARPA-sponsored Vulture
Program (5 year-aloft, 1000 lb solar/battery/fuel-cell powered aircraft).
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