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Vehicle Modeling and SimulationVehicle Modeling and SimulationMatthew Thornton

National Renewable Energy Laboratorymatthew_thornton@nrel.gov

phone: 303.275.4273Principal Investigator: Matthew Thornton

Agreement: 17802DOE Vehicle Technologies Program

Overview of DOE Vehicle Modeling and Simulation R&D

North Marriott Hotel and Conference CenterBethesda, Maryland

February 28, 2008

This presentation does not contain any proprietary or confidential information

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Objective: Vehicle Modeling and Simulation

•

Provide technical analysis of future vehicle technologies and systems to support project planning decisions for both DOE and industry that will impact our dependence on imported petroleum

•

Provide analytical support to DOE and USCAR technical teams addressing current technical R&D barriers and targets

•

Perform analytical assessments of the potential long-term outcome of DOE programs in terms of national petroleum consumption

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Accomplishments FY07 and FY08: Vehicle Modeling and Simulation

•

PHEV Simulations and Analysis– Travel Profile Database – PHEV Impact on Components– Integration with Renewable Fuels– PHEV Economics– PHEV Test Procedures

•

Route-Based Hybrid Vehicle Control

•

Thermoelectric Generator Potential for Vehicle Waste Heat Recovery

•

Integrated Vehicle Thermal Management Modeling

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FY 08 Work Plans: Vehicle Modeling and Simulation

•

Continue PHEV Simulations and Analysis– Medium-Duty Plug-in Hybrid Vehicle Analysis– Expand Travel Profile Database – Analysis of PHEV Impact on Components– Integration with Renewables and Bio-Fuels– PHEV Economics– PHEV Test procedures

•

Route-Based Hybrid Vehicle Control

•

Integrated Vehicle Thermal Management Modeling

•

Exhaust System Thermal Analysis Test Bench

•

Budget: $800K (~40% spent)

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PHEV Simulations and Analyses PI: Tony Markel

•

Provide assessment of the potential benefit of PHEVs and identify pathways for market integration by evaluating operation and performance under “real world” driving conditions, evaluating system component requirements, evaluating costs and benefit trade-offs, and assessing barriers to introduction into the fleet and eventual commercialization

Objective:

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Accomplishments FY 07 & 08: PHEV Simulations and Analysis

•

Processed GPS travel profile data sets provide nearly 2000 real world driving profiles for simulation– Completed simulations for opportunity charge and no-charge

scenarios (FY07)– Spectrum of duty cycles expanded with Los Angeles, Kansas City,

and Tyler data (FY08)•

Assess PHEV Component Impacts– Energy storage, power electronics, emission control (FY07 & 08)

•

PHEV/Biofuels Integration– Used GREET to review PHEV/fuel scenarios and their relative

benefits (FY07)•

Economic Analysis and Marketability– Conducted an attribute-based market study suggesting cost

effectiveness of PHEVs challenging (FY07)– Component cost goals important for reducing initial cost (FY07)– Reviewed potential impacts of incentives and other factors on cost

equations (FY08)•

Test Procedures– Provided 4 recommended revisions to methods for reporting PHEV

fuel consumption (FY 07, continuing in FY08)

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Recharge Scenario Impacts on PHEV Petroleum Consumption Benefits

OpportunityOpportunityChargeCharge(PHEV20)(PHEV20)

No Charge No Charge (PHEV20)(PHEV20)

Opportunity charge: connect PHEV charger to grid any time that the vehicle is parked.

Base Case assumes one full charge per day

~71%

PHEV20 with Opportunity Charge provides greater benefits than PHEV40 with a single daily recharge.

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Travel Profile Data Processing Summary of Newly Processed Travel Data

Each data set stored in a different format Automated processing more challenging than expected

Los Angeles•621 vehicles•Multiple days

TX DOT•Laredo, Tylor, Rio Grande•Austin (in process)

Atlanta (in process)•Multiple weeks for individual households

St. Louis, MO•227 vehicles•Used for Xcel study

Univ. of Michigan Naturalistic Database

Kansas City•368 vehicles

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PHEV Component Impacts Summary

•

Energy Storage– PHEV introduces more long duration power pulses– Time at SOC depends on recharge behavior– Run simulations to set PHEV Battery requirements

•

Power Electronics– PHEVs produce higher thermal loads on PEEMs

and increase battery bus voltage fluctuation

•

Engine/Emissions Control– Charge depleting electric PHEV simulations

suggest potential reduction in emissions by reducing initial daily cold starts and total daily engine starts

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PHEV 40Conventional HEV PHEV 10 PHEV 20

Further reductions with renewable electricity resources

** Assumes national average for electricity mix

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PHEV Economics Analysis: Incentives

Accomplishment– Analyzed energy impacts from incentivizing PHEVs (cars)

•

Currently, a given level of incentives can directly incentivize far more HEVs and overall reduce oil use more than incentivizing PHEVs

•

Current level of federal HEV incentives, however, only replace ~0.1% of the fleet

•

If incentivizing PHEVs helps achieve DOE cost targets, PHEVs may over come the tipping point and have a larger impact than incentivizing HEVs

Significance– Shows a pathway to reduce imported oil through PHEVs

National Gasoline Reduction Cost

$1.23

$2.40

$-

$1.00

$2.00

$3.00

$4.00

HEV PHEV20Gas

olin

e R

educ

tion

Cos

t($

/gal

lon

save

d)

Maximum Gasoline Reduction and Incentive

1.091.37

$- $-0.0

0.5

1.0

1.5

HEV PHEV

Gas

olin

e R

educ

tion

(MB

PD)

$-$0$0$1$1$1

Tota

l Inc

entiv

e (b

illio

ns)

* PHEV20 based on number of cars only, not light trucks

*

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FY 08 Work Plan: PHEV Simulations and Analysis

•

Medium-Duty Plug-in Hybrid Vehicle Analysis

•

Expand Travel Profile Database

•

Analysis of PHEV Impact on Components

•

Integration with Renewables and Bio-Fuels

•

PHEV Economics

•

PHEV Test procedures

•

Budget: 350K (~45% spent)

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Justification and Future Plans: PHEV Simulations and Analysis

•

Supports grater DOE multi-lab PHEV and advanced vehicle technology evaluation efforts, including:– PHEV Demonstration– Vehicle component requirements (e.g. Energy storage and

Power Electronics)– PHEV Benchmarking

•

Perform simulation and modeling to help identify best pathways to fuel savings and fuel diversity with PHEVs

•

Future Plans– On going project supporting PHEV R&D Plan– Use simulation tools to reduce battery coat and extend

battery life– Explore V2G technologies and their ability to affect vehicle

economics and renewables

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Route-Based Hybrid Vehicle Control PI: Jeff Gonder

Maximizing HEV fuel efficiency over known or predictable drive cycles by optimizing the control strategy for that particular driving cycle.

Objective:

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•

Spectrum of possible RBC approaches; establishing a sound comparison baseline is critical for evaluating the benefit

•

Example implementation demonstrates 2-4% fuel savings– Moderated by practical

considerations (relative to effective baseline)

– Considerable in aggregate (if applied across the fleet)

Accomplishments FY 07 Route-Based Hybrid Vehicle Control

Bet

ter f

uel

effic

ienc

y

Less cycle sensitive

No cycle knowledge

Flexible forecasted knowledge about any

cycle

Full knowledge of a single

cycle

7.15

7.25

7.35

7.45

7.55

7.65

-5% 0% 5% 10% 15% 20% 25% 30% 35%

Con

sum

ptio

n (L

/100

km)

NEDC Tuned_lineRoute-Based Control_lineNEDC Tuned_pointRoute-Based Control_point

-2%

-2%

7.15

7.25

7.35

7.45

7.55

7.65

-5% 0% 5% 10% 15% 20% 25% 30% 35%

Con

sum

ptio

n (L

/100

km)

NEDC Tuned_lineRoute-Based Control_lineNEDC Tuned_pointRoute-Based Control_point

-2%

-2%

Same RBC scheduling provides consistent savings across the range of delta SOC

38.3 34.4%0.4%Same RBC vs. Baseline Tuning

Foothills grades with HWFET (mis-

prediction)*

40.1 33.7%2.3%RBC vs. Baseline Tuning (revised)

Foothills grades with US06 high

speed

Change in SOC Range

Consumption Improvement

Control ComparisonCycle

38.3 34.4%0.4%Same RBC vs. Baseline Tuning

Foothills grades with HWFET (mis-

prediction)*

40.1 33.7%2.3%RBC vs. Baseline Tuning (revised)

Foothills grades with US06 high

speed

Change in SOC Range

Consumption Improvement

Control ComparisonCycle

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Accomplishments FY 08 Route-Based Hybrid Vehicle Control

•

SAE paper to be published in April

•

Working with industry partner on transit bus demonstration—in use application of adaptive HEV controls

Work Plan FY08 Route-Based Hybrid Vehicle Control

•

Publish preliminary results

•

Establish industry partner for hardware demonstration

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Budget: $75K (~35% spent)

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Justification and Future Plans: Route-Based Hybrid Vehicle Control

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Supports DOE program goal of assessing advanced vehicle technologies and their impact on petroleum reduction– Low cost solution to implement– Can be transferred to other R&D areas to provide

additional incremental benefits

•

Possible next steps:– Collaborate with a partner for hardware

demonstration (Light-Duty)– Apply approach to other R&D areas

•

PHEV application•

Benefits to other areas (e.g. battery life, emissions…)– Explore translating GPS routes into representative

driving cycle predictions

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Feasibility of Onboard Thermoelectric Generation for Vehicle Waste Heat RecoveryPI: Kandler Smith

• potential fuel savings

• cost/mass analysis

• waste heat availability

30 mph50 mph70 mph

% F

uel S

avin

gs

Car SUV Class 4 Class 8

Fuel saved by shifting from engine- to electrically-driven accessories

Fuel Waste heat to exhaustWaste heat to exhaust

Waste heat

to coolant

TESystem

Fuel Waste heat to exhaustWaste heat to exhaust

Waste heat

to coolant

TESystem

electricity

Questions:System topology?Vehicle platform?Fuel savings?Driving cycle sensitivity?

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Accomplishments FY 07 Feasibility of Onboard Thermoelectric Generation for Vehicle Waste Heat Recovery

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Eliminating alternator loads and shifting engine- driven accessories to electric-driven decreases fuel consumption (2-10% for light duty, 1-15% for heavy duty)

•

Thermoelectric (TE) system cost/mass analysis shows Class 8 trucks (with high mass and VMT) would likely derive more benefit than Class 4 trucks or light duty vehicles

•

Exhaust power analysis indicates that replacing alternator power with a TE system will be difficult (with the possible exception of class 8 trucks)

•

Efficient, small-engine vehicles are least attractive vehicle platform (present highest TE system efficiency requirement; most sensitive to mass increase)

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Integrated Vehicle Thermal Management Modeling PI: Kevin Bennion

Objective

•

Using a systems analysis approach, evaluate methods of optimizing the vehicle’s thermal management systems.

Thermal Challenges/Impacts

•

Operating Temperatures.

•

Reliability.

•

Cost.

•

Volume.

•

Mass.

•

Vehicle Efficiency.

•

Safety.

•

Occupant Comfort.

•

Emissions.Source: International Electronics Manufacturing Initiative (iNEMI) Technology Roadmap – Automotive Chapter, January 2007.

-40 0 40 80 120 160 200 240 280 320 360

Wheel Mounted Components (Brakes)

Passenger Compartment

On-Engine and On-Transmission

Engine Compartment

250 [°C]

85 [°C]

140 [°C]

125 [°C]

Temperature [°C]

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Work Plan FY08 Integrated Vehicle Thermal Management Modeling

Energy Use Sensitivity

Adjust Electrical

Auxiliary Load and Vehicle

Mass

Component Optimization

•

Quantify impact of vehicle thermal management developments through simulation using:– Standard test cycles.– Real world drive cycles.

• Quantify energy use sensitivity to mass and electric auxiliary loads.

• Identify/develop lumped parameter transient thermal models for critical systems to integrate with existing vehicle simulation tools.

• Quantify through simulation potential thermal management opportunities.

• Budget: $150K (~35% spent)

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Accomplishments FY08 Integrated Vehicle Thermal Management Modeling

•

Identify component temperatures.

•

Review current or proposed technologies for:– Waste heat

utilization.– Combined or

integrated cooling.– Ancillary load

reduction.– Improved thermal

management.

-200 0 200 400 600 800 1000

Other Electrical Entertainment Equipment

Heated Mirrors/Winshields Heated/Cooled Seats

EGR Cooler Charge Air Cooler

Fuel Cooler

Alternator Power Steering

Power Electronics Fuel Cell Temperatures

Electric Machine Winding Electric Machine Magnets NdFeB

Battery - HEV/PHEV/EV Battery - 12V Lead Acid

Heated Washer Fluid

Heater Core AC Condenser AC Evaporator Vehicle Cabin

NOx Trap

Thermal Reactors Particulate Trap Diesel

Catalyst Engine Combustion Wall

Exhaust

Refrigerant Transmission Oil

Engine Oil Secondary Coolant Loop (HEV)

Engine Coolant

Temperature [C]

Application/Location Specific

-200 0 200 400 600 800 1000

Other Electrical Entertainment Equipment

Heated Mirrors/Winshields Heated/Cooled Seats

EGR Cooler Charge Air Cooler

Fuel Cooler

Alternator Power Steering

Power Electronics Fuel Cell Temperatures

Electric Machine Winding Electric Machine Magnets NdFeB

Battery - HEV/PHEV/EV Battery - 12V Lead Acid

Heated Washer Fluid

Heater Core AC Condenser AC Evaporator Vehicle Cabin

NOx Trap

Thermal Reactors Particulate Trap Diesel

Catalyst Engine Combustion Wall

Exhaust

Refrigerant Transmission Oil

Engine Oil Secondary Coolant Loop (HEV)

Engine Coolant

Temperature [C]

Application/Location Specific

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Justification and Future Plans: Integrated Vehicle Thermal Management Modeling

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Provides systems approach to addressing waste heat utilization challenges--minimizing heating and cooling system complexity, and reducing mass.

•

On going project transitioning from modeling and analysis of thermal management systems to testing and system integration in a vehicle

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Publications, Presentations•

Markel and Pesaran, “Battery Requirements and Cost-Benefit Analysis for Plug-In Hybrid Vehicles” (Presentation) NREL report PR-540-42082, 2007

•

Markel and Pesaran, “PHEV Energy Storage and Drive Cycle Impacts’ (Presentation) NREL report PR-540- 42026, 2007

•

Gonder and Simpson “Measuring and Reporting Fuel Economy of Plug-In Hybrid Electric Vehicles” WEVA Journal, May 2007

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Markel “Platform Engineering Applied to Plug-In Hybrid Electric Vehicles” SAE Paper No. 2007-01-0292, 2007

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Markel and Gonder “Energy Management Strategies for Plug-In Hybrid Electric Vehicles” SAE Paper No. 2007-01-0290, 2007

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Thornton, Gonder, Markel, and Simpson “Using GPS Travel Data to Assess Real-World Energy Use of Plug- In Hybrid Vehicles” to be published in Transportation Research Record, Washington DC, 2007.

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Pesaran, A., Markel, T., Tataria, H. and Howell, D. “Battery Requirements for Plug-In Hybrid Electric Vehicles – Analysis and Rationale.” Publication & Presentation at EVS-23, Anaheim, CA. December 2007

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Gonder, J. “Route-Based Control of Hybrid Vehicles, Project Description & Status Report.” Presentation to the VSATT, October 4, 2006.

•

Gonder, J. “FY07 Milestone 6.1: Route-Based HEV Control Strategy Report.” DOE Milestone Report, July 2007.

•

Gonder, J. “Route-Based HEV Control, Summary of FY07 Work.” Presentation to the VSATT, September 5, 2007.

•

Gonder, J. “Route-Based Control of Hybrid Electric Vehicles.” Paper (2008-01-1315) & presentation to be delivered at the 2008 SAE World Congress, April 2008.

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Smith and Thornton “Feasibility of Onboard Thermoelectric Generation for Improved Vehicle Fuel Economy” Diesel Engine-Efficiency and Emissions Research Conference, Detroit, MI, August 2007.

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Smith and Thornton “Feasibility of Thermoelectrics for Waste Heat Recovery in Hybrid Vehicles” 23rd International Electric Vehicle Symposium, Anaheim, CA, December 2007.

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