"Race circuit linearization for brake characterization" To assess the brake system performance over long track runs, a test named “BSS” in race track condition is performed This test must be executed on a racetrack, performing a series of runs, which are completed in a certain laptime. This paper presents the development and validation of a tool for race circuit linearization in order to calculate a new standard test which can be carried out in a proving ground (ideally on a circular or oval test track) and that can provide results that can be compared to the ones obtained in the reference track of Lamborghini (below referred as “Ref. Track”) .The tool can generate a new equivalent test, referred as ‘Candidate’, structured like a test with a sequence of acceleration and braking phases. The new candidate test has to be equivalent to “BSS” in terms of brake temperature. In addition, several test requirements must be fulfilled as distance and average speed. The tool could be parametrized to be used for different vehicles depending in the input data (vehicle specs, brake system characteristics, best laptime in Ref.Track etc.). As a first step, a complete dataset of circuit testing and vehicle/brake specification for different vehicle models was studied to develop the different parts of the tool. The tool has been structured in three models/steps to calculate the equivalent “candidate” test: circuit, thermal and fade model. In the circuit model, the tool estimates all characteristics (speed, braking decelerations, time interval etc.) of each section of the “mission” lap with the input of the best laptime and vehicle specifications. Then, thermal model estimates the brake temperature in discs, pads and fluid during a complete BSS session with the calculated “mission” lap from the circuit model. Results of this model will set the target temperatures of the “candidate” test to be reached. Finally, the fade model will generate different proposal/s of “candidate” tests that are equivalent in terms of brake temperatures achieved to the “BSS”. The “candidate” is structured like a brake fading test with a sequence of acceleration and braking phases. The accuracy and efficiency of the tool was evaluated through a series of tests on a vehicle in a proving ground. Results show that the tool is able to provide a candidate test that is equivalent to a BSS in Ref.Track circuit in terms of brake temperature. In conclusion, the tool developed in this study offers a useful and practical tool, providing a cost-effective solution and making it a valuable tool during the brake system development for current and future model vehicles.
Ing. Fabio Squadrani, Senior Manager, Applus IDIADA; Mr. Narcis Molina Montasell, Project Manager, Applus IDIADA; Mr. Antonio Rubio Flores, Project Engineer, Applus IDIADA; Ing. Daniele Rizzello, Team Leader Chassis, Automobili Lamborghini S.p.A.; Ing. Paolo Cesani, Chassis Responsible for Axle, Brakes and Mechatronics, Automobili Lamborghini S.p.A.; Ing. Andrea Macaluso, Vehicle Dynamics/ESC & Brake performance, Automobili Lamborghini S.p.A; Ing. Luca Bertocchi, Vehicle Dynamics, Automobili Lamborghini S.p.A