1. Modeling Tools for Predicting the Impact of Rolling Resistance on Energy Usage and Fuel Efficiency for Realistic Driving Cycles CEC Workshop on Fuel Efficient Tires - 2002 Sacramento, CA September 19, 2002 Kenneth J. Kelly Senior Engineer, Vehicle Systems Analysis Team National Renewable Energy Laboratory

2.  NREL Mission  Lead the nation toward a sustainable energy future by developing renewable energy technologies, improving energy efficiency, advancing related science and engineering, and facilitating commercialization  Established in 1977 as Solar Energy Research Institute (Achieved National Laboratory status in 1992)  One of eleven DOE National Laboratories  Current staff of approximately 1,000  Estimated operating budget of $200M NREL Background

3. US Big 3 Partnership HV program: 55 mpg PNGV: 80 mpg goal FreedomCAR Vehicle Climate Control Battery Thermal Management Vehicle Systems Analysis Digital Functional Vehicle Advanced Vehicle Technologies ProgramGMFord DaimlerChrysler

4.  Potential for Large Energy Savings  Potential to Reduce Environmental Impacts  Impact on the Existing Fleet of Vehicles  Cross-Platform Application  Large and Important U.S. Industry  No Massive Infrastructure Changes Required  Potentially Low Incremental Cost  No Drastic Change in Consumer Behavior Required NREL’s Interest in Tires

5. Highway Energy Consumption GAP 2.7 mbpd 6.7 mbpd

6. Potential Energy Savings in the Transportation Sector Total year 2005 savings 3.8 billion gal /year Equivalent to replacing average car with: 15.7 MILLION Toyota Priuses

7. Introducing: NREL’s Advanced Vehicle Simulator

8. Available on the world wide web at: (http://www.ctts.nrel.gov/analysis)

10. Three Main ADVISOR GUI Screens Vehicle Input Simulation Setup Results

11. Basic Structure (database) How the Data/Models are Pulled into the GUIBlockDiagram GUI Data Files

12. Basic Structure (models) In the Matlab/Simulink EnvironmentBlockDiagram Libraries Battery Engine Control

13. ADVISOR Setup Screen with Tire Menu

14. New rolling resistance model in ADVISOR 2002 with J2452 test data supplied by Michelin

15. ADVISOR Rolling Resistance Block Diagram

16. Tire Sizes Currently in ADVISOR Database

17. ADVISOR Simulation Setup Screen with Drive Cycles

18. ADVISOR Results Screen

19. ADVISOR Results : Energy Use Figure

20. ADVISOR Simulation Results : F r on the EPA’s Highway (HWFET) Cycle

21. ADVISOR Simulation Results : F r on the EPA’s Urban (UDDS) Cycle

22. ADVISOR Simulation Results : F r on the EPA’s Aggressive Driving (US06)Cycle

23. ADVISOR Simulation Results : Road-Load Energy and Fuel Economy3.3% US06 5.9% HWFET 2.1% FTP % change in FE Low RR vs med RR (30% lower Fr)

24. ADVISOR Simulation Results : Road-Load Energy and Fuel Economy1.9% US06 3.4% HWFET 1.5% FTP % change in FE Low RR vs med RR (19% lower Fr)

25. Parametric Sweep on rolling resistance showing the effect on fuel economy ADVISOR is linked to optimization techniques and other tools in our Digital Functional Vehicle toolkitOptimizationTools ADVISOR g(x) Constraint Function f(x) Objective Function

26. Bringing it all together with Digital Functional Vehicle an integrated systems approach

27. NREL’s Energy-Smart Tire Vision Adaptive Properties and Self Regulating Energy Savings Improved Performance Improved Safety Low Rolling Resistance Large Energy Savings Long Life Reduced Solid Waste Reduced Particulate Pollution Energy Savings from Manufacturing and Materials

28. Conclusions and Additional Information  Potentially, Large Energy Savings Available from Energy Efficient Tires Efficient Tires  Government/Industry Partnership for More Detailed Analysis, Testing and Direction and Direction  Tires Represent One of Only a Few Opportunities for Energy Savings in the Existing Fleet in the Existing Fleet  ADVISOR Model - Fast and Accurate Vehicle Systems Model - Free (http://www.ctts.nrel.gov/analysis) - Open Source Code - Vehicle, Component, Drive Cycle Library Included - Conventional and Advanced Vehicle Configurations