is that considered active suspension?

[mariano.torre.gomez]

I am wondering if that is considered an active suspension?
Tenneco kinetic suspension
if it is not
why its use is not extended in racing cars?

[RideRate]

Depends. If it's just the old interconnected suspension it's purely passive. If you've got actuators forcing movement dependent on collected information it's some level of active. The interconnected has been used (see FSAE and rally car). I'd guess its use is not widespread because it's (1) not legal (2) doesn't give enough enhanced performance for a particular racing series (3) overly complicated for other types of series.

Find out exactly how it operates and we can determine if it'd be technically passive, semi-active, or active.

Looks like this company has acquired the kinetic name and technology from the Australia company.

[mariano.torre.gomez]

http://www.autozine.org/technical_schoo ... nsion3.htm

tenneco has 2 systems the one described above dont look to me ilegal, the second one includes some intelligence.
efectivenees? i dont know
but with several extra valves I believe it could control "pitch and yaw"
another question
would make sense to have mechanical roll bars, and "hidraullical control of pith and yaw"?

[matt21]

I think the second picture of the system is similar to this one:

http://scarbsf1.wordpress.com/2011/10/1 ... uspension/

But if you use any valves as you are then altering the suspension behavior. Then this is an active system and illegal.

[mariano.torre.gomez]

ok understood
but 2nd question remains
would be posible(or would make sense) to combine with mechanical bars to reduce pitch and yaw?

[matt21]

Why do you want to use mechanical bars then?
You can use the system parallel or crossover to control heave and roll.

For pitch control you have to link the front and rear.
I´m not sure if this is allowed.
You should check the regs.

[mariano.torre.gomez]

Yeah I like the idea to link front and a rear
I dont see any reason why should be forbidden?

[Richard]

I believe they are allowed to link front and rear, but none do at the moment.


Scarbs mentioned it in a blog.. http://scarbsf1.wordpress.com/2011/10/1 ... uspension/

[DaveW]

So far as I'm aware (i.e. the last time I looked) any hydraulic coupling is permitted, including connection to a pressurised supply, perhaps with one or two debateable exceptions. What is not allowed is any form of electrical connection.

The issue with hydraulic solutions is compliance (both fluid & pipes), related time delays, and fluid volumetric thermal expansion coefficient.

[aleks_ader]

So far as I'm aware (i.e. the last time I looked) any hydraulic coupling is permitted, including connection to a pressurised supply, perhaps with one or two debateable exceptions. What is not allowed is any form of electrical connection.

The issue with hydraulic solutions is compliance (both fluid & pipes), related time delays, and fluid volumetric thermal expansion coefficient.

That is main problem! How make system more consistent?

Maybe is solution coling system around the piston and pipes?

[Dragonfly]

Due to the very low compression ratio of the hydraulic fluid, the links can be considered as solid rod links with the benefit of the absence of complicated mechanical parts and tuning the system by varying gas pressure and fluid pass holes/valves diameter in the accumulator spheres where the gas acts as the spring.

Note: Just an opinion of a layman who happens to drive a Citroen.

[matt21]

I think the hardest thing to make this thing work is to get around these rules:

10.2.2 Any powered device which is capable of altering the onfiguration 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.

With this, the use of porwered valves is forbidden.
Anybody an idea how you can do this with unpowered devices?

How do they switch from "parallel" to "cross-over"? And is this not considered an adjustment to the suspension system?

[DaveW]

I think the hardest thing to make this thing work is to get around these rules:

You are not wrong, which is what makes the topic fascinating.

One of the problems is that the components of a suspension are not defined - at least I don't think they are. That would include the elements themselves & the way they are coupled or linked.

Your quote from 10.2.2, taken at face value, would imply that a damping device that changed characteristics (i.e. performance) with temperature (that would be all of them) are not permitted. Alternatively, since the major source of heat is the engine, engines are not permitted... reductio ad absurdum.

It could be argued that any "passive" changes in response characteristics that might be engineered to benefit the vehicle must be acceptable, provided only that the change doesn't directly cause the suspension to move (10.1.2).

[DaveW]

Due to the very low compression ratio of the hydraulic fluid, the links can be considered as solid rod links with the benefit of the absence of complicated mechanical parts and tuning the system by varying gas pressure and fluid pass holes/valves diameter in the accumulator spheres where the gas acts as the spring.

Note: Just an opinion of a layman who happens to drive a Citroen.

I have a very high regard for the Citroen hydro-pneumatic system. What they achieved, at relatively low cost, was remarkable. Certainly, in the context of that application hydraulic fluid can be considered incompressible - but that is not always the case. Fluid compressibility has a measurable effect on the performance of race car dampers &, I recall, it also affected the performance of the "hydraulic rocker" that was the basis of the Tyrrell system.

[Smokes]

Didn't it get banned from WRC citroen won the wrc in 2003,2004,2005 with it. And current used by toyota for there landcruiser and lexus and nissan for the patrol and mclaren for the MP4-12C’s as there proactive chassis control. http://www.caranddriver.com/features/th ... ed-feature
It is a passive system but it more of an evolution of citroen self leving supension. The designer is using the system for boat call nauti-craft which can keep the deck level in high seas.