Pressure for a Comfortable Ride

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Pressure for a Comfortable Ride

Compressing air in shock absorbers has been an effective way for automotive engineers to minimize the impact of bumps to a vehicle’s ride and take the harshness out of surprise potholes on poorly maintained or unimproved roads. One of the problems with the pneumatic design in these air suspension systems is the space requirement for the air cavity to be effective. Using activated carbon, a given amount of air space can produce at least twice the desired results. When force is applied to the load bearing surface of the activated carbon in a pressurized storage container, the activated carbon changes and limits how closely the air (or carbon dioxide, CO2) molecules can be compressed. As a result, the stiffness of the pressurized air increases more gradually and more linearly instead of exponentially, as it normally would without the activated carbon.

The activated carbon is not unlike the material used in some gas or liquid filter designs based on organic carbon. In this case, the material can be coal dust, sawdust or coconut shells. The exact consistency and additional processing can tune its response for a different adsorption rate in different designs and applications. In the air suspension application, the pressure in the container is around 0.5 to 5 MPa (72.5 to 725 psi).

This patented approach is already used in Audi A6 and A7 air suspension systems. It has applications in ride control and air suspension seats in numerous vehicles as well as in speakers and noise cancellation systems

A cup full of activated carbon | Source: Carbon Air Limited

At room temperature a cup full of activated carbon will contain about 6 times as much air as a cupful of air.
Source: Carbon Air Limited.

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