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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 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.

The driving comfort influences the customer purchase decision; hence it is an important aspect for the vehicle development. To better quantify the comfort level and reduce the experiment costs in the development process, the subjective comfort assessment by test drivers is nowadays more and more replaced by the objective comfort evaluation. Hereby the vibration comfort is described by scalar objective characteristic parameters that correlate with the subjective assessments. The correlation analysis requires the assessments and measurements at different vehicle vibration. To determine the objective parameters regarding the powertrain excitations, most experiments in the previous studies were carried out in several test vehicles with different powertrain units.