Investigation on Brake-Drag-Optimization on Vehicle-Level


To be published on 09/08/2024

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Authors Abstract
Brake drag in disc brakes occurs during the off-brake-phase, when the brake is not applied but friction contacts between brake disc and pads persist. First and foremost, the resulting drag torque increases energy consumption, where a few Newton meters can have a significant impact on the range which is a crucial feature in particular for battery-electric-vehicles. Moreover, brake wear is accelerated in conjunction with enlarged taper-wear of the pads. Additional wear can also imply increased brake particle emissions which are going to be limited by upcoming regulations due to their potential health risk. In this light different countermeasures aim to create and maintain a sufficient air gap between brake disc and pads after the brake is released. Common examples are the optimization of the piston sealings and the corresponding seal-grooves to improve piston retraction as well as integrating pad springs into the caliper to push the pads back. State of the art to analyze the effectiveness of countermeasures are brake dynamometer tests. As they provide high repeatability and an accuracy below 0,5 Nm which is necessary to develop brakes with drag near zero. Though the laboratory environment usually excludes influencing factors that are present on vehicle-level and can have a significant impact on brake drag, for example lateral acceleration. Therefore, this work uses a relatively new approach for direct drag torque measurement based on piezo-electric sensors to analyze the effects of different countermeasures during full-vehicle testing. Different test-vehicles are equipped with the measurement system along with additional sensors for brake monitoring like temperature and brake pressure. During roller dynamometer tests, certain driving maneuvers on proving grounds as well as tests on the road, different countermeasures are tested and compared to default brake setups. In addition, brake drag is increased by misuse to demonstrate possible impacts under suboptimal conditions.
Meta TagsDetails
Huchtkoetter, P., Neubeck, J., and Wagner, A., "Investigation on Brake-Drag-Optimization on Vehicle-Level," SAE Technical Paper 2024-01-3037, 2024, .
Additional Details
To be published on Sep 8, 2024
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Technical Paper