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Oversteer/Understeer Characteristics of a Locked Differential
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English
Abstract
The type of differential used in a vehicle has an important and often-neglected effect on handling performance. This is particularly important in racing applications, such as in IndyCar racing, in which the type of differential chosen depends on the course being raced (superspeedway ovals, short ovals, temporary street courses and permanent road courses). In the present work, we examine the effect of a locked rear differential on oversteer/understeer behavior. Using a linear tire model, it is shown that employing a locked differential adds a constant understeer offset to the steering wheel angle (SWA) -v- lateral acceleration vehicle signature. A computer simulation of steady-state cornering behavior showed that the actual effect is much more complicated, and is strongly influenced by static weight distribution, front/rear roll couple distribution, available traction and the radius of the turn being negotiated.
Testing performed on a Formula SAE racing car was used to verify the simulation results, and to examine limit-performance differences between theory and experiment.
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Citation
Hopkins, P. and Metz, L., "Oversteer/Understeer Characteristics of a Locked Differential," SAE Technical Paper 942485, 1994, https://doi.org/10.4271/942485.Also In
References
- Smith, C. “The Racing Differential,” Race Car Engineering 3 5 1994
- Momiyama, F. Kiyoto, H. Junichi, K Takashi, H. “Tractive Torque Steer for On-Center Stability-Handling Augmentation with Controlling Differential Gear for Large-Sized Vehicles - A Comparison with Passive Rear-Axle Steer,” SAE Paper No. 912688 1991
- Pacejka, H. B. Bakker, E. “The Magic Formula Tire Model,” Tire Models for Vehicle Dynamics Analysis Vehicle Systems Dynamics 21 1 18 1992
- Chen, S. Y. Tsai, L. W. Chen, J. Holloway, D. C. “Steady-State Handling of Four-Wheel All Terrain Vehicles (ATV's) SAE Paper No. 891117 1989
- Allen, R. W. Szostak, H. T. Rosenthal, T. J. Kleyde, D. H. “Steady State and Dynamic Properties of All Terrain Vehicles Related to Lateral Directional Handling and Stability SAE Paper No. 891105 1989
- Faldella, R. Tamburro, A. “Four-Wheel Drive in High Performance Cars,” SAE Paper No. 905110 XXIII FISITA Congress 1989