NVH measurements - noise, vibration, harshness
Problem: Audible and perceptible vibrations
Goal: Increase in ride comfort
The noise and vibration behavior (NVH = Noise, Vibration, Harshness) of vehicles is increasingly becoming the focus of attention in automotive development regarding ride comfort. This refers to all audible and perceptible vibrations coming from the chassis, powertrain and wheels that affect comfort. Battery-powered drives pose a particularly great challenge in this respect, since there is no combustion engine to mask the other drive noises and these can be perceived more easily as body or airborne noise. Several effects can be named as the cause of the drive noise. Thus, excitations from the drive side can occur, which are caused by the electric motor, the gear transmission or by the drive shafts. Certain component groups can react to these structure-borne noise excitations with natural vibrations and additionally worsen the NVH behavior.
To measure and evaluate vibrations, rotational speeds are recorded at the torsional vibration-exciting components. At the same time, structure-borne sound signals are recorded with an accelerometer and microphones and then jointly evaluated in the order and frequency ranges. ROTEC offers high-resolution analog measurement boards with ICP inputs and special NVH features in the analysis software for NVH investigations.
The recorded measured values are evaluated in the time and spectral domain. The acoustic behaviour is also analyzed.
Furthermore ROTEC ENGINEERING provides you with support and technical engineering know-how for problems related to vibration analysis of engines, transmissions and drive trains. With our know-how, we make a valuable contribution to your product in the areas of timing gear validation, valve train optimization, clutch design, transmission errors (TE), transmission optimization, oil supply optimization, powertrain measurement and optimization, current and voltage analysis, and the application of measurement technology.
Time domain analyses
- Analysis of the characteristics of structure-borne sound signals over time or shaft revolutions
- Correlation between dynamic movement of components and noise effects
- Causal research of gear rattling or similar NVH issues
Spectral domain analyses
- Visualization of the composition of a soundscape
- Analysis of single orders and total noise level
- Analysis of the conspicuousness and dominance of a noise component
- Detection of resonances
- Comparison of the sound image at different locations
- Verification of the effectiveness of sound insulation