Objective:
The main focus of our work is the investigation of the vibro-acoustic behavior of engines and components. In detail we locate and analyze sound sources and use different approaches to achieve noise and vibration attenuation. On the one hand, there is the widely used passive approach. On the other hand, active control approach can effectively support passive noise treatments to minimize unwanted structural vibration and noise in a lower frequency range.

Measuring rooms:
In order to evaluate the acoustical quality of an engine, several tests on an acoustic engine test bench (anechoic room) can be carried out. These experimental investigations involve stationary engine operating points and engine running-ups for different loads. The cylinder pressure signals can be measured using an indicating system.
Separate components can be analyzed in an anechoic laboratory. By means of an impact hammer or a shaker, the freely suspended components are excited.

Engine in an anechoic room	Test setup in an acoustics laboratory

Measurement of airborne noise:

• Sound pressure level determination and frequency analysis with the help of microphones in the near and far field
• Intensity probe to determine the radiated acoustic power in difficult measuring environments
  (sequential measurement enables sound mapping)
• Microphone arrays for sound source localization

Combo-array

Grid-array  (self-made)                                    Intensity probe

Measurement of structure-borne noise:

•  Laser vibrometer and acceleration sensor to detect the vibrational behavior of a measurement point
•  Scanning laser vibrometer to illustrate the shape of vibration modes on the outer surface

3D acceleration sensor mounted on the bearing bracket	Scanning laser vibrometer