Brembo (United Kingdom)

<div class="section abstract"><div class="htmlview paragraph">Brake pads employing innovative hydraulic inorganic binders in place of common state-of-the-art thermosetting phenolic resins have been produced by means of a unique prototypal equipment and a distinctive manufacturing process. The unicity of the process enables us to exclude completely any thermal cycle in the manufacturing steps, with a considerable positive energy balance compared to the standard counterpart. Realized brake pads have indeed been successfully tuned to meet the braking performances of phenolic counterparts. In the present work our latest efforts in this field are illustrated, focusing our attention to three main areas of interest: performance, energy consumption, volatile organic emissions. One selected exponent of our cementitious-based material is reported, demonstrating its capability of matching both standard OE and AM braking performances (investigated through a full scale brake dynamometer by SAE J2522 procedure), and its feasibility to be released as an actual AM material according to ECE R90 regulation (road test on vehicle). The energetic evaluation of the employed technology in term of prototypal manufacturing process and employed raw materials has been established, demonstrating the advantages of this new system compared to the standard one. Our investigation finally reports selected thermo-chemical analysis (TG-EGA and pyrolysis PY-GC/MS) devoted at identifying the key organic compounds potentially/eventually emitted during braking at various temperatures. Our material shows a dramatic drop of the volatile hazardous/organic compounds (VHCs/VOCs) released by a standard phenolic homologous, thus increasing the favorable characteristics of such inorganic hydraulic-binder brake pads and related technology.</div></div>

<div class="htmlview paragraph">The paper reports on an experimental investigation of the aero-thermal flow field configuration at the exit of a vented automotive brake disc. The main goal is to obtain a deeper insight of the aero-thermal phenomena upon which brake efficiency strongly depends; a second goal is to generate a complete data set for CFD code validation.</div> <div class="htmlview paragraph">A multiple pin disc geometry was tested at two disc rotational speeds and at four moderate braking conditions. The experiments were mainly focused on a coupled thermal and fluid dynamics survey. Local mean temperature and velocity measurements at disc exit were carried out in the relative frame; global parameters, as the vented mass flow rate, the heat power released to the vented air and the internal convective heat transfer coefficient were then evaluated.</div> <div class="htmlview paragraph">It was found that the flow structure does not really change, varying the rotational speed and the braking conditions. The heat power increases with increasing the disc temperature, but it does not scale with rotational speed. The convective heat transfer coefficient showed quite large values, reducing for higher disc temperatures. The convective heat transfer coefficient variation for different Reynolds number was found to be consistent with empirical correlations generally used for heat exchangers.</div>

<div class="htmlview paragraph">As the community is becoming more and more aware and conscious of the pollution problems caused by the internal combustion engine and its use in transportation, we are now seeing the first projects and prototypes regarding hybrid and electrically-powered vehicles.</div> <div class="htmlview paragraph">One of the main problems witnessed by engineers has been that of the relatively low operating range provided by the storage batteries available on the market today, and so, recovering the energy that is inevitably lost during braking is of primary importance.</div> <div class="htmlview paragraph">The concept of regenerative braking is fairly simple as it consists in making the electric motors function as generators.</div> <div class="htmlview paragraph">In many of today's applications we find two indipendent controls for the operation of the hydraulic brake and for the activation of regenerative braking. The choice on which braking mode to use, or in which sequence the two modes are to be used is left to the driver who, at the onset of braking, is forced to make mental considerations in order to activate the two braking modes in the right sequence. Furthermore, the driver must not forget to disable the regenerative function at the end of each stop.</div> <div class="htmlview paragraph">BREMBO has designed a braking system in which a single control, that is, the brake pedal, activates and disables in the right sequence the two different braking modes, thus allowing:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"> <div class="htmlview paragraph">to maximize energy recovery by the electric motors each time the driver steps on the brake pedal;</div> </li> <li class="list-item"> <div class="htmlview paragraph">the hydraulic brake to be used in addition to regenerative braking when the latter is not enough to produce the required deceleration.</div> </li> </ul> </div> <div class="htmlview paragraph">The proposed braking system is lightweight and versatile. It can be adapted to the different powertrain configurations seen on various electric vehicles.</div>