Advancing the State-of-the-Art in Tire Testing

The Tire SocietySeptember 21, 2010

Camber Ridge, LLC

Dr. James F. Cuttino, Presidentjcuttino@camberridge.com

www.camberridge.com704-575-1688

Camber Ridge, LLC

Agenda

• Motivation for Examining Current Capabilities

• Lab-Based Tire Testing• On-Road Tire Testing• Pros and Cons• A Design Proposal• Conclusions

MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN 2

Camber Ridge, LLC

Motivation• FMVSS 126 Protocol for Electronic Stability Control

• 100% Compliance by September, 2011

• Current development relies heavily on prototype testing on proving grounds

• Each prototype vehicle = $500,000 (passenger car)

• 50 - 100 prototypes to production

• NCAP Rollover Protocols• Similar developmental costs

• In summary, need to simulate extreme maneuvers • Requires dynamic inputs in slip angle, loads, camber

• Simulations rely on projected curves and extrapolation

3MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Motivation• Heavy Truck Industry

– Few facilities can handle size / highloads (10,000 - 15,000 lbs normal)

– High torque requirements

– Durability testing

– Tire harmonics

– Rolling Resistance / Fuel Economy

– Pending regulations for electronic stability control

– Impact of customer-specified options (including tires) on vehicle compliance with regulations

– New regulations for stopping distance

4MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

In-Lab Testing Systems

Akron Standard (early 1900’s)

5MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Subtleties of Design

Freudenmann, T., Unrau, H.-J., and El-Haji, M., ‘‘Experimental Determination of the Effect of the Surface Curvature on Rolling Resistance Measurements,’’ Tire Science and Technology, TSTCA, Vol. 37, No. 4, October – December 2009, pp. 254-278.

• Care required not to introduce parasitic errors

6MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

In-lab Testing SystemsPrüfstand für Fahrzeug/Fahrbahn

Federal High- way Research Institute (BASt), Germany

7MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Bristol (concrete)Atlanta

Camber Ridge, LLC

Modeling the Surface(Samples from Race Tracks in the US)

TalledegaDarlington Texas

Concord

80 Grit Sandpaper

8MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

On-road Testing Systems

9MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

GM Tire Cornering Test Vehicle

Cortese, A.D., and C.S. Rockafellow, “General Motors Proving Ground Tire Cornering Test Vehicle”, SAE Transactions, 1971-02-01, Paper 710092

Correction Wheel5th Wheel

Sensor

Correction Wheel

Test Wheel

Test Wheel

10MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

On-road Testing Systems

1972 - Michelin PLR

Citroën components, two small-block Chevrolet 350 V-8s, one to drive test tire, other to power the vehicle.

11MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Current In-lab Systems• Pro’s

– Controlled environment– Good Repeatability– Historical Data Pool– Industry Standard– 24-7 Operation

• Con’s– Simulated road surface - concerns on accuracy – Load limits, depending on application– Torque magnitude and control– Limits on wet traction studies, etc.

12MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Comparison of Belt vs. Asphalt

Increasing Slip

M. G. Pottinger, G. A. Tapia, C. B. Winkler, and W. Pelz, "A Straight-Line Braking Test for Heavy Duty Truck Tires," Paper No. 45, ACS Rubber Division, Cleveland, OH, 10/17-20/95, published in Rubber World, Vol. 214, No. 6, September 1996, pp. 29-36.

13MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Comparisons of 2 Belt Coatings

M. G. Pottinger, G. A. Tapia, C. B. Winkler, and W. Pelz, "A Straight-Line Braking Test for Heavy Duty Truck Tires," Paper No. 45, ACS Rubber Division, Cleveland, OH, 10/17-20/95, published in Rubber World, Vol. 214, No. 6, September 1996, pp. 29-36.

14MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Belt vs. On-road Results

M. G. Pottinger, G. A. Tapia, C. B. Winkler, and W. Pelz, "A Straight-Line Braking Test for Heavy Duty Truck Tires," Paper No. 45, ACS Rubber Division, Cleveland, OH, 10/17-20/95, published in Rubber World, Vol. 214, No. 6, September 1996, pp. 29-36.

Belt Machine On-road Trailer

15MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Comparison of 3 Common Lab Configurations

Freudenmann, T., Unrau, H.-J., and El-Haji, M., ‘‘Experimental Determination of the Effect of the Surface Curvature on Rolling Resistance Measurements,’’ Tire Science and Technology, TSTCA, Vol. 37, No. 4, October – December 2009, pp. 254-278.

MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN 16MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Rolling ResistanceFlat Hydrodynamic Bearing, 1.71 m Drum, 2.0 m Drum

Freudenmann, T., Unrau, H.-J., and El-Haji, M., ‘‘Experimental Determination of the Effect of the Surface Curvature on Rolling Resistance Measurements,’’ Tire Science and Technology, TSTCA, Vol. 37, No. 4, October – December 2009, pp. 254-278.

Discrepancy largest for 2.0 m drum

17MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Current On-road Systems• Pro’s

– Realistic operating conditions – Ability to study affects such as temperature– Control over surface and profiling (asphalt,

concrete, cleats, etc.)– Wet traction, snow, other

• Con’s– Repeatability dependent on ability to control

environment– Compliance of system limits loads– Metrology frame coupled with load frame– Dependence on driver variability– Limited throughput

18MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Braking Results vs. Track Location

Treichel and Drahne, Tire Tests with a New Tracking System for Passenger Cars, SAE 880581, 1988.

Uncontrolled Braking Position

Braking Position Controlled

19MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Effect of Temperature on Braking Performance

Treichel and Drahne, Tire Tests with a New Tracking System for Passenger Cars, SAE 880581, 1988.

Increasing Temp

20MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Opportunities for Improvement

• Limitations to existing technologies:– Generally limited to quasi-static testing conditions– Limited load ranges, particularly for belt machines – Limited torque applications in

driving / braking– Generally simulated surfaces (drums,

belts, abrasive surfaces)– Often restricted to lower speeds – Open loop operation forces

dependence on carpet plots and lookup tables for dynamic simulations

21MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Opportunities for Improvement

• Opportunities to advance state-of-the-art– More realistic interface– Wet traction, off-road (military), etc.– Dynamic input– High torque braking (heavy truck, aircraft)– ABS braking / system analysis– Long distance wear studies– Rolling Resistance– Drift and Pull– Hardware in the Loop Capabilities

22MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

“Ideal” Design Approach

• Contact Interface rules - protect at all costs.• Simplify design as much as possible.• Separate load loops from metrology loops

where possible and appropriate.• Consider modularity, flexibility.• Control environment while providing

variability.• Minimize special order components.

23MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

“Ideal” Design Approach

– Accuracy vs. Repeatability• Each has its place

– Resolution / Sensitivity• High loads and torques vs.

Rolling resistance, drift and pull, uniformity

– Constraints and actuation• Force Inputs - downforce, torque, Fx, etc.• Displacement Inputs - Yaw Angle, Camber

Angle, Steer Angle– Rigid constraints critical for controlled,

displacement based inputs

24MOTIVATION LAB-BASED ON-ROAD PROS/CONS DESIGN

Camber Ridge, LLC

Conclusion

• Tire Testing has advanced significantly over the years

• Advances have been incremental, following two fairly distinctive paths

• Understanding the history of tire testing provides a strong foundation for developing the next generation of testing capabilities

• Next meeting of the Camber Ridge Consortium is in late October

25

Camber Ridge, LLC

Camber Ridge, LLC

Camber Ridge, LLC