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The functional extension of vibration reduction in continuous slip operation in modern wet-running clutch systems under dynamic excitation is being investigated by the authors. Therefore, a mixed virtual-physical validation environment has been developed using the IPEK X-in-the-Loop Framework and will be presented as part of this contribution. Thus, the validation environment enables the consideration of interactions with the residual systems, especially the residual drive train. In this contribution, the validation environment is used to investigate whether and how an attribute variation in the subsystem, respectively the tribological system, can provide improved vibration reduction without increased power dissipation due to damping but other reducing mechanisms favored. The results show significant differences in vibration reduction behavior whereas the power losses are almost the same between the investigated tribological system.

Fuel cell electric vehicles are expected to support the effort to overcome the economic and ecological challenges in the automotive sector. Just as battery electric vehicles, fuel cell electric vehicles also offer locally emission free mobility. The drive system of fuel cell electric vehicles consists of a fuel cell system, an electric motor, power electronics, a hydrogen storage system as well as a rechargeable energy storage system, typically a battery. The quantified power ratio between the fuel cell system and the rechargeable energy storage system is referred to as the degree of hybridization, although inconsistent definitions are used.

With the electrification of vehicles, new questions and problems are rising in the field of NVH. The in-cabin noise was reduced significantly due to the new drive system. Additionally, the spectral composition of this noise changed dramatically. While the reduction of the in-cabin sound pressure levels is generally welcomed by customers and engineers alike, the predominantly high-pitched tonal sounds of the electrical drives are normally perceived with less enthusiasm. Active sound design can help both in masking those noises, or at the least embed them in new harmonic contexts so their annoyance can be reduced. A variety of research in the field of traffic psychology shows that acoustical feedback can alter the driving behavior. Based on this, our idea is, that if certain sounds induce specific reactions in drivers, a specifically designed active sound design could be used to influence said behavior.

Due to the increasing number of hybrid and full electric vehicles and the trend of generally decreasing noise levels in vehicles, the engineering fields regarding driving comfort and NVH issues become more challenging: The masking effect of combustion engines vanish while customer expectations towards NVH and driving comfort are growing. Also the trend to high-speed concepts in electric vehicles combined with high transmission ratios implies that dominant powertrain noise will shift from low frequency phenomena as in combustion engines to higher frequencies that have a much higher annoyance potential [1]. In most cases the vibroacoustic behavior of a drivetrain or that of the whole vehicle is not known until the system is already in operation, since vibroacoustic behavior is very complex and difficult to simulate.

The “Extended Target Weighing Approach” (ETWA) presented here describes a holistic, cross-subsystem, function-based lightweight design method - in terms of conceptual lightweight design - for the identification and evaluation of lightweight design potentials in the concept phase of product development. It systematically extends the existing “Target Weighing Approach” (TWA), in order to balance key factors mass, costs and CO2 emissions. During the application of the method, concept ideas are generated which have to be evaluated with regard to their potential. The selection of concept alternatives to be pursued in the early phase of product development often depends on the experience of the product developer. Therefore, the potential of some concepts is not recognized correctly or the risk according to the intended solution caused by missing knowledge or uncertainties is misjudged.

In terms of customer requirements, driving comfort is an important evaluation criterion. Regarding hybrid electric vehicles (HEVs), maneuver-based measurements are necessary to analyze this comfort characteristic [1]. Such measurements can be performed on acoustic roller test benches, yielding time efficient and reproducible results. Due to full hybrid vehicles’ various operation modes, new noise and vibration phenomena can occur. The Noise Vibration Harshness (NVH) performance of such vehicles can be influenced by transient powertrain vibrations e.g. by the starting and stopping of the internal combustion engine in different driving conditions. The paper at hand shows a methodical procedure to measure and analyze the NVH of HEVs in different driving conditions.

The driving comfort is an important factor for buying decisions. For the interior noise of battery electric vehicles (BEV) high frequency tonal orders are characteristic. They can for example be caused by the gearbox or the electric drive and strongly influence the perception and rating of the interior noise by the customer. In this contribution methods for measuring, analyzing and predicting the excitation by the dynamic torque of the electric drive are presented. The dynamic torque of the electric drive up to 3.5 kHz is measured on a component test bench with the help of high frequency, high precision torque transducer. The analysis of the results for the order of interest shows a good correlation with the acoustic measurements inside the corresponding vehicle. In addition an experimental and numerical modal analysis of the rotor of the electric drive are performed.

The requirement of the start of the internal combustion engine (ICE) not only at vehicle standstill is new for full hybrid electric vehicles in comparison to conventional vehicles. However, the customer will not accept any deterioration with respect to dynamics and comfort. ICE-starting-systems and -strategies have to be designed to meet those demands. Within this research, a method was developed which allows a reproducible maneuver-based analysis of ICE-starts. In the first step, a maneuver catalogue including a customer-oriented maneuver program with appropriate analysis criteria was defined. Afterwards, the maneuvers were implemented and verified in a special test bench environment. Based on the method, two sample hybrid vehicles were benchmarked according to the maneuver catalogue. The benchmarking results demonstrate important dependencies between the criteria-based assessment of ICE-starts and the embedded ICE-starting-system and -strategy.

The driving comfort is an important factor for buying decisions. Especially for battery electric vehicles (BEV) the acoustic quality is an elementary distinguishing feature, since the masking of an internal combustion engine (ICE) is no longer present. Opposing the importance of the acoustic quality is the lack of knowledge of how to measure and interpret the high frequency noise generated by an electric powertrain with respect to the NVH behavior influencing the passengers [1, 2]. In this contribution a method for measuring and interpreting the transfer path of acoustic phenomena from the drivetrain of a battery electric vehicle into the passenger cabin is presented. Due to the lack of masking by the ICE in case of BEV, high frequency phenomena must be considered as well. In order to determine the airborne transfer function from the electric powertrain to the driver cabin, a dodecahedral speaker is used for reciprocal measurements.

In contrast to passenger cars, commercial vehicles exist in many layouts for different customer applications. The Daimler AG provides with their Mercedes Benz Trucks a product portfolio of 6 commercial vehicles (Econic, Atego, Axor, Actros, Zetros, Unimog), which are available in a multiplicity of model variants. Therefore, the well-known driving cycles of passenger cars such as NEDC (Europe), the 10-15 mode (Japan), the FTP & FTP75 (USA) and others cannot be used in regard to fuel consumption or dimensioning of a commercial vehicle [1, 6, 15]. A diversification of type and usage of the commercial vehicles is obligatory necessary, as already shown in publications of Holloh et al. [10] However, this paper offers a method which uses collected data from customers, in order to develop objective reference cycles or test cases. This described method can be equally used for both, creating the reference cycles of commercial vehicles mentioned above, as well as passenger cars.