Sorry about my last post. I talked about a previous thread on this, but I had it at another place...
This is what I wrote, abbreviated to suit this thread:
Originally Posted by zac510
The rumour was that Ferrari F1's system changed the viscosity based on the travel of the damper, so at near maximum travel it stiffened up or something like that. Which is still passive, because it is repeatable and not modified by electronics.
Relevant regulations:
10.2 Suspension geometry:
...
10.2.2 Any powered device which is capable of altering the configuration or affecting the performance of any part of the suspension system is forbidden.
10.2.3 No adjustment may be made to the suspension system while the car is in motion.
I'd guess there is a problem with article 10.2.2 (and less blatantly with 10.2.3), if you somehow use an electric external source to "magnetize" the liquid.
This forbids, for example, the (active) suspension developed by Bose (yeah, the sound guys), that relies on ultra-hyper-extra powerful magnets:
Bose suspension
In a regular shock adsorber, the deflection valves are like round washers, but they are in the shape of a truncated cone: if you see them from the edge, they are not a line, the outer part of the circle is upwards of the center part. The picture I am posting is terrible, it has only one deflection valve on the bottom chamber, I do not know why.
When the pressure in the liquid increases, the washer "clicks" and reverses its form, allowing the liquid to pass. The more pressure, the more clicks you'll get and more fluid will pass, absorbing with less resistance big movements while keeping the car "stiff" on small vertical movements of the tyre, when the valves are closed.
The racing shock absorbers I have worked with have a lot more valves than the ones in the picture (at least in the rebound side). What you regulate when you tune the car is the size of the holes and the size of the washers of this valves.
There are a couple (well, four) improvements to the basic shock absorber I know.
The
first are the gas charged ones. There you have a gas on a "third" chamber that has compressed nitrogen. This has two purposes: first, the increased pressure of the gas makes harder for the air and the liquid to mix. A mixture of gas an liquid is compressible, while a liquid is not. With less aireation the shock absorber is more consistent: normal shock absorbers get "mushy" after a while (not all the problems you get at the end of the race come from tyre degrading... ). Secondly, the gas pressure precharges the shock absorber, making it stiffer. This pressure will not help to increase the height of a car. The reason gas shock absorbers extend by themselves is a little more tricky: the area of the piston on the upper part of the valve is reduced (because of the shock absorber rod) and thus a differential pressure will develop.
Second, shock absorbers with a dual resistance have been devised. In this case, you have two shock absorbers, one inside the other (crudely speaking). The first one is "soft" and takes small irregularities of the road. The second one takes big bumps (is stiffer) and makes the car less prone to pitch an rolling. They also have tapered grooves on the pressure tube that allow the fluid to bypass the main valve while the shock absorber is in a middle zone and forces all the liquid to pass through the main valve when it is extended or compressed too much.
Third, there are acceleration sensitive shock absorbers: they have special valves that are sensitive, not only to the velocity of the fluid, like the dual resistance ones, but sensitive to G-forces. I know the Monroe Reflex. In this model, there is a "twin valve": the normal valve and a bypass around it, concentrical in what appears to be just one valve.
Fourth, there is a speciall kind of acceleration sensitive shock absorbers, really ingenious (well, at least I didn't "get it" when I saw them for the first time... ). They are also called mono-chamber absorbers (at least in spanish). Of course, they only have a chamber. The chamber has a free-floating dividing piston, that separates compressed nitrogen gas in the lower section, from the liquid in the upper section, over the dividing piston. The pressure of the gas in this case helps to sustain the vehicle. The dividing piston moves freely keeping the liquid chamber full at all times, as the pressure piston (the normal piston of a regular shock absorber) moves up and down.
Well: does an F1 car use one of these four kinds? Or there is a fifth type?
I'll continue with a second post on magnetic-rheological dampers.
