Brake System Homologation: A Holistic, Simulation-based Approach

To comply with EU7 in a first step brake systems of newly homologated passenger cars and light commercial vehicles up to 3.5 tons must fulfil the upcoming certification limits, according to the EU7 implementation timeline. Based on a wide range of brake emission measurements since 2022, it can be seen that almost no brake system is fulfilling these currently foreseen limits. Brakes have been optimized for decades now for mainly performance and comfort improvements, but now legal emission requirements are acting as a game changer and huge efforts will be necessary to fulfil new and tradtitional purposes, which are causing new modelling and testing approaches to understand the complete vehicle picture with all its attributes. A possible contribution to solving this challenge is the use of the vehicle-specific individual friction brake share coefficient ("iFBSC"), which is currently mostly evaluated by performing a WLTP-Brake cycle on a roller testbed and analysing the relative amount of non-friction braking within this cycle. The corresponding limitations (e.g., the focus on one specific recuperation or - maybe more precisely - the propulsion strategy and/or the brake family) make this approach costly and difficult. To be able to optimize propulsion strategies and, as a consequence, the expected brake emissions upfront homologation, simulation might be a possible tool to increase efficiency and therefore significantly reduce development costs.