Noise Path Analysis for Four-Wheel Drive Vehicle

[harvi101]

The figure1 shows a for the configuration of a four wheel drive vehicle. The body is mounted on a chassis frame through a series of body mounts. The engine and transmission mounting points are also shown. The engine has two front mounts and a single gearbox mount to a body cross member.
Figure 2 shows the results for a nosie path analysis of second order (2E) interior noise component in 3rd gear at 3600 rpm. This has been carried out to investigate a booming problem occurring at this engine speed in all gears.
1. For wat frequency is the analysis in figure2 ?
2. Given the result in figure 2, what is ur conclusion about the noise at 3800 rpm ?
3. What additional specific information would the noise path analysis give that would provide valuable guidance to the NVH development engineers in their pursuit of a solution to the booming noise problem ?
4. Discuss solutions to the problem. Consider specifically whether changes to the acoustics pack might be efficacious. What other design modifications would be worth investigating ?
http://img651.imageshack.us/img651/1727/p25031015490001.jpg

 

[Navin A S]

1. The analysis in Figure 2 is for the frequency range 500 - 2000 Hz.2. From Figure 2, it can be concluded that there is a significant increase in noise at 3800 rpm.3. The noise path analysis would provide information about the source of the booming noise problem, the transmission of noise through the vehicle structure and the areas of the interior where the noise is most pronounced. This would help the NVH development engineers to identify and address the root causes of the problem.4. Possible solutions to the problem include: implementing changes to the acoustic pack to reduce resonance, increasing the damping in the body mounts, and adjusting the engine and transmission mounts. Additionally, modifications to the body structure and mounting points could be considered, such as changing the body cross member or adding additional sound insulation.