Veröffentlichungen

In the automotive industry, one of the principal issues is to ensure the comfort of vehicles as much as possible. High vertical accelerations of the vehicle body transmit undesired vibration, causing malaise to passengers. Car vehicles are subjected to vibrations induced by the road roughness or, during a curve travelling, by the roll motion. These factors contribute to generating the total vertical acceleration. The vertical acceleration due to the first factor can be decreased by correctly dimensioning the stiffness and damping of the suspension. In this paper, the active control of the camber angle of the rear wheels is proposed to reduce the vertical acceleration due to the roll motion. The proposed technique has been applied to a validated vehicle model developed in the ADAMS Car environment. The trailing-arm type rear suspension has been modified to include actuators functional for the control system implementation. The tracking of the variable vehicle body roll angle by rear wheels is allowed exploiting two PID controllers to improve the contact of the tire with the road and, therefore, the ride comfort. Two manoeuvres called Sine Steer and Fish-hook have been employed to validate the designed controllers. The RMS and the maximum value of the vehicle body's vertical acceleration decrease, demonstrating the employability of the proposed control system to improve ride comfort.

This article deals with methods and measurements related to environmental pollution and analysis of particle distribution in urban and suburban landscapes. Therefore, an already-invented sampling method for tyre road wear particles (TRWP) was used to capture online emission factors from the road. The collected particles were analysed according to their size distribution, for use as an input for particle distribution simulations. The simulation model was a main traffic intersection, because of the high vehicle dynamic related to the high density of start-stop manoeuvres. To compare the simulation results (particle mass (PM) and particle number (PN)) with real-world emissions, measuring points were defined and analysed over a measuring time of 8 h during the day. Afterwards, the collected particles were analysed in terms of particle shape, appearance and chemical composition, to identify the distribution and their place of origin. As a result of the investigation, the appearance of the particles showed a good correlation to the vehicle dynamics, even though there were a lot of background influences, e.g., resuspension of dust. Air humidity also showed a great influence on the recorded particle measurements. In areas of high vehicle dynamics, such as heavy braking or accelerating, more tyre and brake particles could be found.

Friction brakes are one of the main sources of PM emissions from cars today. However, due to the electrification of the powertrain, the share of friction brakes in vehicle deceleration is continuously decreasing. Due to the reduced number of braking applications and the lower brake pressure level, the amount of emitted particles also decreases. This is associated with the disadvantage of an increased potential for the formation of rust on the surfaces of the friction materials, which is expected to influence friction and wear. Due to the increasing challenge posed by corroded friction partners, drum brakes are increasingly used to decelerate bat-tery electric (EV) and hybrid electric vehicles (HEV). In this study, basic investigations on the particle emission behaviour of drum brakes are carried out using an inertia dynamometer (LINK 3900-NVH). To en-sure representative sampling, a constant-volume sampling system is used, which is optimised in terms of transport efficiency and particle distribution. Condensa-tion particle counters (CPC) and filter holders (TX40) are used to determine PN/PM emission factors. CPCs with differently calibrated cut-off are used to evaluate the formation of nanoscale particle formations. In this context, special at-tention is paid to the influence of temperature on the particle formation process. From the comparison between rear-axle disc brake and rear-axle drum brake it could be proven that the predominant part of the wear mass remains within the drum, which affects the size distribution of the emitted particles. The ratio be-tween PM10 and PM2.5 mass-related emissions factors decreases from about 2 (disc brake) to about 1.3 (drum brake). In addition, the emission behaviour is dif-ferentiated via the bedding procedure of the drum brake. To achieve a reproduci-ble emission level, a doubling of the number of cycles (WLTP-brake cycle) is necessary. Due to a higher temperature level, nanoparticles could be detected dur-ing testing of the drum brake, whereby the number-related emission factor (PM2.5) was partly higher than for the disc brake.

The paper describes methodology and corresponding environment for development, validation and testing of complex electric vehicle (EV) systems. The proposed approach is based on distribution of relevant design tasks between remotely working testing equipment with real-time (RT) data sharing and data exchange. The approach is demonstrated by the example of X-in-the-loop (XIL) environment uniting electric motor test setup, hardware-in-the-loop (HIL) platform with brake-by-wire system, and the brake dynamometer. The study introduces how this configuration of experimental tools can be used by designing the brake blending and control of an EV.