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This paper presents an introduction to the requirements for shock absorbers in e-vehicles by means of a comparative study of two pure-electric vehicles from different OEM's tested in real road conditions. In this investigation the focus was on the shock absorbers, the most critical suspension components with regards to ride comfort. Different damper designs were used to investigate both in the vehicle and on the test bench. The results of the analysis in the time and frequency domains are presented.

One of the main reasons for unsatisfactory perception of vehicle interior acoustics is the vibration transfer through the suspension into the vehicle body structure. The interaction between the different chassis components and between chassis components and the vehicle body plays a decisive role in vibration generation. Suspension layout, body impedance at the attachment points, body properties and interior acoustic properties are the main parameters which should be considered when optimizing chassis components in regards to NVH behavior. In past practice, test measurements of individual chassis components were used for NVH optimization. A disadvantage of this process is that analysis and improvement of vehicle acoustics are performed in a rather late phase of development and thus involve great expenses. A new approach to targeted acoustics improvement of chassis components will be shown based on examples of shock absorber optimization.

The vibration characteristics of the shock absorber in the dynamic condition differ from the “quasi-static” characteristics. For analysis of the processes occurring in the shock absorber, measurements were carried out on a universal servo-hydraulic test rig. The principle arrangement is described. A twin-tube shock absorber was prepared with acceleration, oil pressure and valve lift sensors. To understand this changing of the operating characteristics the analysis of the vibration system “shock absorber” was carried out. The rote cause for damping force irregularities was found. With knowledge of the valve operating characteristics in conjunction with the internal pressure characteristics, effective optimization strategies can be pursued.

Noise and vibration are critical to a customer’s overall positive or negative perception of passenger cars. Increasing market demands regarding comfort mean that a vehicle’s acoustic features must demonstrate continuous improvement to remain competitive. In the new model car, the influence of vibration excitation (caused by force) and noise transfer (transfer functions) of suspension should be investigated by considering the three dimensions of noise behavior of the vehicle. Measurement under real operating conditions using a servo-hydraulic multi-channel test rig was chosen. The level of the excitation was chosen in such a way that the coherence on the response signals was mostly above 90%. It was found that noise sensitivity of the upper transfer path (piston rod - upper mount - body – interior) is distinctly higher than the lower transfer path (shock absorber tube - lower mount - wheel carrier - chassis - body – interior).

Noise and vibrations are very important aspects in overall customer perception of passenger cars. The optimal layout of the damper and the damper mount is a crucial criterion with respect to interior noise. In this article, the damper and the damper mount are viewed as a vibrational system. The article shows how the damper module's vibrational properties can be optimized with the help of a system analysis. Measurement and analysis processes developed specifically for this purpose are explained. The application of damper simulations for noise reduction is presented. Problems in assessing damper noise are discussed, and the use of artificial-head technology to analyze psycho-acoustic noise is presented. Examples are used to illustrate the process of acoustic damper optimization.