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passive-active suspension (my own design)
Posted: 09 Apr 2010, 17:22
by Scania

the red one is normal damper, the lower black line is lower arm, the blue 1 is n2 Gas.
when the wheel move up/ chassic move down, the damper will be compressed normaly, but the N2 gas piston will also compressed, it supply extra pressure to the damper to push it back, when the well move down/ chassic move up, the gas piston will also move down, it decrease the pressure in the gas chamber, it pull the damper piston up & the wheel will move down. that means the distance of the supension moving will be shorter, so the height different between filled up & no fuel of the car will be lesser.
Re: passive-active suspension (my own design)
Posted: 09 Apr 2010, 17:48
by autogyro
Sorry Scania, I cant understand it.
You cannot change the volume of a liquid in a sealed cylinder.
Re: passive-active suspension (my own design)
Posted: 09 Apr 2010, 17:58
by hecti
the concept is right(it makes sense to me) but the way its drawn is wrong, shocks operate of a rocker, they arent directly attached to the push rod
edit:
nvm
i dont think it works, its kind of a "moveable" bump stop that depends on the position of the rocker, but i think it would just make the suspension rock hard
just my thoughts
Re: passive-active suspension (my own design)
Posted: 09 Apr 2010, 18:00
by RH1300S
Or you could put harder springs on the car....
Re: passive-active suspension (my own design)
Posted: 09 Apr 2010, 18:13
by hecti
RH1300S wrote:Or you could put harder springs on the car....
yea, thats basically what this is
Re: passive-active suspension (my own design)
Posted: 09 Apr 2010, 18:31
by RH1300S
Actually, mine was a quick and lazy response.
I came back here to correct it.....but hecti got there first. Effectively it's like a progressive spring or adjustable bump stop.
YOu could achieve the same effect from rockers, so it doesn't matter that it's drawn as the suspension arm - the effect can still be the same.
If you are speculating on what might control ride height with diffent fuel loads.
Isn't the important word 'LOAD'? Your system would seem to be sensitive to movement not load. So a simple bump rubber would achieve the same effect.
The problem that F1 cars have with fuel levels is in trying to achieve the same ride height with different loads being fed into the system.
Re: passive-active suspension (my own design)
Posted: 10 Apr 2010, 13:05
by mep
Eh why do you all say it is the same like a progressive spring or makes the suspension hard?
For me it’s the opposite, it makes the suspension very weak/soft.
Scania you said that you want the second cylinder filled with N2 gas.
A damper works when it presses a very high viscose liquid through a small opening. The faster the piston moves the more flow resistance this creates.
When you have a gas in this system, then the gas will get compressed first.
It's relative easy to compress a gas even when it is already under high pressure.
So you will not manage to press much liquid through your piston because all movement will come from the gas compression.
Even worse this gas has only stored the energy and will release it when you remove you external force like a spring.
So you create an oscillating system.
Re: passive-active suspension (my own design)
Posted: 11 Apr 2010, 01:58
by Ted68
I get what you are aiming at, scania.
Citroen had a very, very similar system in the mid-80's. Instead of working on a single axle theirs acted diagonally. This came out around '86-88 when Lotus' active system was all the rage.
Cheers
Re: passive-active suspension (my own design)
Posted: 11 Apr 2010, 02:49
by Scania
Ted68 wrote:I get what you are aiming at, scania.
Citroen had a very, very similar system in the mid-80's. Instead of working on a single axle theirs acted diagonally. This came out around '86-88 when Lotus' active system was all the rage.
Cheers
more detail plz?

Re: passive-active suspension (my own design)
Posted: 11 Apr 2010, 08:35
by Ted68
A little more complicated than my aging brain remembers, but still on the same track.
http://www.autozine.org/technical_schoo ... nsion3.htm
Re: passive-active suspension (my own design)
Posted: 11 Apr 2010, 09:21
by Just_a_fan
Ted68 wrote:I get what you are aiming at, scania.
Citroen had a very, very similar system in the mid-80's. Instead of working on a single axle theirs acted diagonally. This came out around '86-88 when Lotus' active system was all the rage.
Cheers
BMC had a system in the '60s called Hydralastic. Became Hydragas in later Rover cars.
Re: passive-active suspension (my own design)
Posted: 11 Apr 2010, 10:04
by timbo
Sorry for a bit of OT, but I remember there were talks ahead of 1995 season that Tyrrell had very innovative "mechanical active" suspension.
Can anyone provide some more info?
Re: passive-active suspension (my own design)
Posted: 13 Aug 2013, 23:30
by roblomas52
Just_a_fan wrote:Ted68 wrote:I get what you are aiming at, scania.
Citroen had a very, very similar system in the mid-80's. Instead of working on a single axle theirs acted diagonally. This came out around '86-88 when Lotus' active system was all the rage.
Cheers
BMC had a system in the '60s called Hydralastic. Became Hydragas in later Rover cars.
Yeah, they used it on the Mini's until they realised it was to expensive and reverted the mini back to normal suspension
Re: passive-active suspension (my own design)
Posted: 13 Aug 2013, 23:34
by KeithYoung
I can't see the image.
Re: passive-active suspension (my own design)
Posted: 14 Aug 2013, 04:56
by DaveW
If Scania is still interested, then he might try looking up Nivomat....