Understanding Order in Sound Plots in Automotive Industry

[CuriousWon]

I work in the automotive industry and some of the products we make are resonators for engines. I always hear talk about "order" (2nd order, 4th order, etc) in sound plots. What are they referring too? Is there a good site out there that can give me the basics?

 

[FredGarvin]

It somewhat depends on the usage in your particular field. In most cases I have seen, the order refers to a multiple of a fundamental frequency. In your case that would probably be the once per rev engine speed. So a second order vibration would be a vibration with a frequency of 2X of engine speed. In the vibration analysis world, the order of the vibration is a first indicator of a source for the vibration. For example, a first order (or as I am used to saying, a 1E) is a very good indication of a shaft imbalance.

I found this page related to automotive engines that probably will give you what you need.

http://www.vibratesoftware.com/html_help/html/Diagnosis/Engine_Speed_Related.htm

 

[astrokreng]

As a scientist in the field of automotive engineering, I am familiar with the concept of order in sound plots. In this context, "order" refers to the harmonic content of sound waves. Harmonics are multiples of the fundamental frequency of a sound wave, and they contribute to the overall quality and character of the sound. In the automotive industry, sound plots are used to analyze the acoustic performance of resonators and other components in the engine. These plots often include information about the order of the sound waves present.

For example, a 2nd order sound plot would indicate that the sound wave has a fundamental frequency and a harmonic at twice that frequency. A 4th order sound plot would have a fundamental frequency and three additional harmonics at 4, 6, and 8 times the fundamental frequency. The higher the order, the more harmonics present in the sound.

There are many resources available online that can provide a more in-depth explanation of order in sound plots. Some good starting points include websites and articles from academic institutions, automotive engineering organizations, and scientific journals. Additionally, your company may have internal resources or experts who can provide further information and guidance specific to your products and industry.