What is the ideal damper for a passenger car suspension?

In summary, the conversation discusses the design of front suspension for a passenger car, with the main focus being on achieving maximum comfort at different speeds. The speaker mentions a desired damping ratio of 0.2 and the importance of having different damping levels during rebound and bump. They also express concerns about selecting a suitable damper from the market and mention resources such as a book and online forums for assistance.
  • #1
hackashack
8
0
I've been a bit lost figuring out what damper I should be using for the front suspension I am designing. Right now I'm running a wheel rate of 60 lbf/in at the front with a ride frequency of 1.2254 Hz. The front is also supporting a sprung mass of 391.68 lbf. Comfort is the end requirement of the design where the car will be operating at city and highway speeds of around 60km/h and 100km/h.

From what I've been reading a damping ratio of about 0.2 is suitable for a passenger car to maximize comfort in bump. I am aware that just working with that damping ratio all throughout the force velocity curve is not ideal because the ride can be very uncomfortable at high velocities and I am also aware that the damping should be higher during rebound compared to bump. Currently I am trying to work towards a force velocity curve that has a similar profile as shown in the attachment I've uploaded. However, I am having difficulty determining how much more damping I want in rebound compared to bump as well as where I should have the split between high and low velocity.

Another thing that I'm concerned about is when I do actually finalize my desired force velocity curve, how can I select a damper on the market that will behave similarly to that curve? I've been looking around in catalogs but all they help you with is the sizing and choosing the appropriate damper for a particular model of vehicle and I don't believe manufacturers are willing to reveal their force velocity plots for their dampers because it may be confidential information. Any help would be appreciated!
 

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  • Force Velocity Curve.PNG
    Force Velocity Curve.PNG
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  • #2
Do you access to this book, shock absorber handbook (2nd ed)? Amazon let's you look at a lot,

https://www.amazon.com/dp/0768000505/?tag=pfamazon01-20

Another place to ask experts,

http://www.f1technical.net/forum/viewtopic.php?f=6&t=8937&start=285

I like a Google image search,

https://www.google.com/search?q=sho...5KuH9sATspYLAAg&ved=0CB4QsAQ&biw=1360&bih=649

Google book preview shows quite a bit of the first edition of "shock absorber handbook".

https://books.google.com/books?id=0...A#v=onepage&q=shock absorber handbook&f=false
 
Last edited by a moderator:

1. What is a damper and why is it important to select the appropriate one?

A damper is a mechanical device used to regulate or control the flow of air, gas, or liquid. It is important to select the appropriate damper because it affects the performance and efficiency of the system it is used in. A properly selected damper can save energy, reduce noise, and improve indoor air quality.

2. How do I determine the appropriate size of a damper for my system?

The size of a damper depends on the size of the duct it is being installed in. The general rule of thumb is to select a damper with an opening size that is equivalent to the duct size. However, other factors such as air flow rate, pressure drop, and system requirements should also be considered when selecting the appropriate size.

3. What types of materials are commonly used for dampers?

The most common materials used for dampers are galvanized steel, aluminum, and stainless steel. Galvanized steel is the most economical option and is suitable for most applications. Aluminum is lightweight and corrosion-resistant, making it suitable for outdoor use. Stainless steel is the most durable option and is often used in high-temperature or corrosive environments.

4. How do I know if I need a manual or motorized damper?

A manual damper is operated by hand, while a motorized damper is operated by an electric or pneumatic motor. The type of damper you need depends on the level of control you require. If you need to adjust the damper frequently, a motorized damper would be more convenient. If the damper will remain in a fixed position, a manual damper may be sufficient.

5. Are there any codes or standards I should follow when selecting a damper?

Yes, there are codes and standards that govern the selection and installation of dampers. The most common ones include the International Mechanical Code (IMC), National Fire Protection Association (NFPA) 90A and 90B, and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Handbook. It is important to consult these codes and standards when selecting a damper to ensure compliance and safety.

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