Estimated impact of future vehicle technologies on brake

Estimated impact of future vehicle technologies on brake particle emissions With special Focus on Electrification of Powertrain and Driver assistance Systems Florian Guckeisen, 47 th PMP-Group-meeting, Ispra, 17 th of May 2018

Agenda Motivation Potentials Risks and open questions Conclusions / Outlook

Motivation

Motivation Current focus of PMP-Group, followed by Task Forces, is on the two main aspects: I: Definition of a representative Driving Cycle to be used for bench tests II: Definition of a Measurement Setup to characterise the emitted particles

Motivation Current Megatrends in Automotive Industrie Digitalisation Electrification of Powertrains Autonomous Driving › › › › Connectivity / Car-2 -x … E-Motor / Power Electronics Batterie- / Charging-Technology Operating-Strategies Algorithms / Artificial Intelligence Sensors / Actors Driver Assistant Systems Ref: Bode/Tiedemann, “E-Antriebe u. Rekuperation”, 5. VDI-Fachkonferenz „Innovative Bremstechnik“, Hannover, 26. 10. 2017 What are the effects of these trends for brake particle emission behaviour of vehicles?

Potentials

Driver Assistant Systems and BPE(1) Driver Assistant Systems can influence the driver‘s behaviour to a more efficient style - also by reducing usage of friction brake. The following described (or similar) technology is currently in series use at several OEMs. - The Predictive Efficiency Assistant (PEA) informs the driver in advance about the upcoming necessity to decelerate, based on GPS-system data (topography, bends, speed limits etc. ) and vehicle sensors (Camera, Radar etc. ). - When using the system with Adaptive Cruise Control (ACC) the car takes over the longitudinal dynamic control. For efficiency and comfort reasons the level of deceleration is reduced due to usage of freewheeling, motor brake, recuperation (if available) and earlier getting off the drive pedal. - All these effects reduce significantly the use of friction brake – if the driver is willing to follow the advices / lets the car take over the longitudinal control. www. youtube. com/watch? v=y 0 qxk. Xnz. UGA

Driver Assistant Systems and BPE (2) Outlook for future extensions of predictive efficiency systems: - Combining PEA with Car-to-X-Communication systems can even increase the potential of the before described system as the car knows up-to-date about upcoming obstacles / construction sites / … - The need to increase range of electric vehicles makes it necessary to use this potential even more -> Using the friction brakes means losing energy. - Autonomous driving cars (Level 3, 4, 5) in general need to drive as comfortable as possible, as the driver turns to passenger – Risk of Sea Sickness Robot-Taxi Audi Aicon © Audi AG - All these trends might reduce the usage of friction brake only for emergency braking or long mountain descent. BPE is being reduced accordingly.

Electrification of Powertrains and BPE (1) Also Regenerative Braking reduces usage of friction brake (schematic description) ► Phase 1 (brake initiation): friction brake, later being ramped down when Power demand due to high velocity is reduced ► Phase 2 (full recuperation): 100% generator ► Phase 3 (near standstill): Technologies) generator being ramped down, 100% hydraulics for v → 0 (not mandatory for all x. EV- decel. in %g / speed in %vmax 100 vehicle speed 1 2 3 friction brake based deceleration demand Recuperation based deceleration 0 time in s

Electrification of Powertrains (2) With the potential to recuperate kinetic energy in electric vehicles the use of friction brake corresponds to a loss of energy and range. Accordingly there is an general interest to avoid this usage. Vehicle test activities in customer oriented driving cycles in Audi show already with rather low electric recuperation performance installed in a HEV that: 12 Disc Temperature - The necessary brake pressure level is reduced accordingly Occurence in % - Brake disc temperature is being reduced significantly 0 0 Average brake pressure Tmax Occurence in % 30 The dissipated energy by friction brake is reduced by almost 50% (Front axle) 0 0 pmax With Recuperation No recuperation Ref. Bode/Tiedemann, “E-Antriebe u. Rekuperation”, 5. VDI-Fachkonferenz „Innovative Bremstechnik“, Hannover, 26. 10. 2017

Electrification of Powertrains (3) With increasing electric performance (as installed in PHEV and BEV) in general the recuperation potential is higher. The chart below shows a state-of-the-art operating map of a recuperation system in which the brake applications of standard driving cycles are marked. Brake applications in NEFZ, WLTP, FTP 72, HWFET almost completely in 100% recuperation range 0 Recuperation Potential Deceleration in ms-1 100% 0% 10 0 vehicle velocity in km/h vmax As the driving cycles correspond (more or less) to a worldwide average of vehicle usage it can be seen, that almost all of these applications can be done without using the friction brake - and so without generating any BPE.

Risks and open questions

Risks and open question Beside the Potential for Brake Wear Emission Reduction there is of course also some risk for counter-effects: - A friction brake based on todays technology might never reach bedded conditions - with the effect of increased BPE. - Current brake discs pads do suffer on non-usage. Rusted surfaces could correspond to bad bedding condition of the friction couple. - What will be the Market Penetration of these technologies at which time in the future? How does this affect

Conclusions / Outlook

Summary / Conclusion As shown before future vehicle technologies will have the potential to reduce significantly BPE. - Driver assistant systems can influence the drivers brake usage behavior in a way that can be assumed to be relevant for the generation of BPE. - The more these systems reach automated driving skills, taking the human driver out of the loop, the higher these effects can be considered. - Vehicles with electric powertrain (x. EV) do have an additional brake system on board, that does not create any BPE. This system is preferably to be used as it can gain back kinetic to electric energy. The potential of this system can be sufficient for most of the daily use brake applications. - For the remaining applications operating temperatures, pressure levels and so energy dissipation of friction brake is reduced. Significantly reduced BPE can be considered. - In opposite there are certain risks not well investigated yet about the specific BPE behaviour of a rarely used friction brake. With the objective to define standard test setups to objectively characterise BPE of vehicles, the above mentioned effects should be considered within the activities of the PMP-group.