High downforce race car vertical dynamics: aerodynamic index

ABSTRACT Race car performance is strongly affected by aerodynamics. Due to downforce generated by the vehicle floor (i.e. diffuser), vehicle ride heights are key parameters to improve performance, and the coupling of aerodynamics and suspension is one of the key points of race car setting. This work focuses on the suspension and aerodynamic coupling from the vertical dynamics point of view. Besides road holding performance, for race cars, aerodynamic performance and stability are major factors. Downforce decreases laptime (the main performance target) but pitch instability is a non-desired effect that can happen in high downforce race cars. A new vertical dynamic performance index is proposed through the use of simulation to improve aerodynamic performance and understand the pitch instability phenomenon. This new index uses all relevant vehicle nonlinearities related to vertical dynamics and can handle a specific track profile and vehicle speed range, allowing the analysis be conducted according to a circuit specification. A previously validated Formula 3 car model was used as an example.

[1]  Henri Kowalczyk,et al.  Track Simulation and Vehicle Characterization with 7 Post Testing , 2002 .

[2]  Daniel Chindamo,et al.  The influence of suspension components friction on race car vertical dynamics , 2017 .

[3]  Thomas Michael New.  RANDOM ROAD ANALYSIS AND IMPROVED GEAR RATIO SELECTION OF A FRONT WHEEL DRIVE DRAG RACING CAR , 2008 .

[4]  A. Flammini,et al.  Smartphone-based system for the monitoring of vital parameters and stress conditions of amatorial racecar drivers , 2015, 2015 IEEE SENSORS.

[5]  Massimiliano Gobbi,et al.  AERODYNAMIC EFFECTS ON RIDE COMFORT AND ROAD HOLDING OF AUTOMOBILES , 1996 .

[6]  Henri Kowalczyk,et al.  Damper Tuning with the use of a Seven Post Shaker Rig , 2002 .

[7]  T D Gillespie,et al.  Fundamentals of Vehicle Dynamics , 1992 .

[8]  R. Scott Floyd,et al.  Use of Simulation to Tune Race Car Dampers , 1994 .

[9]  Simone Wannemaker,et al.  Dynamics Of Atmospheric Flight , 2016 .

[10]  Marco Gadola,et al.  Reproduction of real-world road profiles on a four-poster rig for indoor vehicle chassis and suspension durability testing , 2017 .

[11]  Xin Zhang,et al.  Aerodynamics of a heaving airfoil in ground effect , 2011 .

[12]  Joseph Katz,et al.  Race Car Aerodynamics: Designing for Speed , 1996 .

[13]  David Vetturi,et al.  Suspension System Testing and Tuning with the Use of a Four-Post Rig , 1998 .

[14]  Marco Gadola,et al.  Upright mounted pushrod: the effects on racecar handling dynamics , 2016 .

[15]  Roberto Spinola Barbosa,et al.  Vehicle Vibration Response Subjected to Longwave Measured Pavement Irregularity , 2012 .

[16]  E. Harry Law,et al.  Simulation and Analysis of Suspension and Aerodynamic Interactions of Race Cars , 1994 .