An Active suspension idea..

[fastback33]

Aero produces a force, which is then dircted through the suspension components to the ground. What if you had a program that created artifical downforce, for the suspension, that would react in such a way that you had some amount of down force acting on the entire body of the car.

This was my million dollar idea, that i thought of about a year ago, and left it on the back burner in my head until today, when i began to think about it again. (Not to mention my absolutely off teh wall idea, that i won't even bother mentioning for fear of being laughed out the door. It really is off the wall.)

So, guys how would this work? I was thinking that you would have an electronic program, but one of the problems i ran into was how do you regulate this? meaning how do you decide how much DF (downforce), would act on the suspension naturally? any solutions or other ideas you guys can bounce off would be great!

[mahesh248]

Well downforce will increase when speed climbs , to bring you idea into actuall practise would be a challenge , those active suspenions were already introduced and banned in F1 a decade before ,


the best possible way to control or make the suspension acitve is to control the anti roll bar , or something other mechanical device , which is independent of the air , its going to be difficult to make a active suspesion with respect to the areodynamic downforce , beacause it totally depends on the speed of the car.

[modbaraban]

Active suspension was first raced by Colin Chapman's Lotus in '83 I think. It was banned shorlty.

[MrT]

You couldn't create downforce like this if my understanding of what your suggesting is correct. If your saying you effectivly push the wheels into the ground by hydralics acting on the suspension, the chassis would just raise... you could achive an impulse of force increase (due to the inertia of the sprung mass) but could not sustain the extra wheel loads. Look at it as a free body force diagram, you have a car of mass M supportted by 4 wheels. There are no other external loads (if we ignor aero for a second). Whatever you do inside that system will not affect the equilibrium of the 4 wheels supporting M/4*g Newtons each.

Now the reason aero loads work is that they are an EXTERNAL load, and hence increases the contact patch loadings.....

[Belatti]

Sir Isaac Newton, a man that was born more than 350 years ago, well, he can explain to you why your idea is impossible to achieve.

Newton's Third Law states that for every action there is an equal and opposite reaction.

Thats why MrT, explained well to you, wrote:

If your saying you effectivly push the wheels into the ground by hydralics acting on the suspension, the chassis would just raise...

[DaveKillens]

The activer suspensions of the past worked to maintain a consistent ride height for the entire chassis. That way, the ground clearances would be minimalized at all times, and the chassis could acheive maximum downforce, at all times.
First and foremost, you have to get maximum grip, at all times. If the nose porpoises, or a wheel is displaced too much on a bump and the chassis is too far above the road surface (just as examples, you lose diwnforce. These days the engineers try through different means (the sprung weight on the nose of the Renault is a good example), but the goal is to get, and maintain a specific ride height.

[ferrarimw]

what other uses does active suspension have outside motorsport? ive always wondered why it is not used on ambulanes to avoid patients incurring more pain etc? IS it just currently too expensive for comercial use?

[Carlos]

That sounds like a self leveling suspension system. The most famous is the Citroen DS hydraulic system
http://en.wikipedia.org/wiki/Citro%C3%ABn_DS

The Bose self leveling system
http://www.bose.com/controller?event=VI ... c=PRJCTSND

[modbaraban]

what other uses does active suspension have outside motorsport? ive always wondered why it is not used on ambulanes to avoid patients incurring more pain etc? IS it just currently too expensive for comercial use?

Looks like it (regarding the ambulances). However I've seen TV reports about its intruducion in the military aera. They showed a Hummer able run over bumps without distracting the riflemen from shooting

[checkered]

Fully active suspension

systems in current (or what are currently described as such, 2007) cars: Acura (MDX), Audi (A8, Q7, R8, RS4, S8, TT), Bentley (Continental Flying Spur, GT, GTC), BMW (5, 6, 7, Alpina B7, M5, M6, X5), Buick (Lucerne), Cadillac (DTS, Escalade, ESV, EXT, SRX, STS, XLR, XLR-V), Chevrolet (Corvette, Suburban, Tahoe), Ferrari (599 GTB Fiorano), GMC (Yukon, XL), Jaguar (S-Type, XJ, XK), Land Rover (Range Rover, Range Rover Sport), Lexus (GS430, GS450h, GX470, LS 460, LX470), Maserati (Quattroporte), Maybach (57, 62), Mercedes-Benz (CL, CLS, E, GL, M, R, S, SL), Porsche (911, Boxster, Cayenne, Cayman), Rolls-Royce (Phantom), Toyota (Land Cruiser), Volkswagen (Touareg 2), Volvo (S60, V70). A bit surprised by the number of US made cars, they have a reputation of sporting suspensions dating from the horse and carriage era - leaf springs and such. How those go with sophisticated electronics, or are they a fit at all, I don't know.

There must be more manufacturers, makes and models, but these I found easily. Note, though, that terminology is deceptive: The most sophisticated F1 "active suspension" systems had the tracks programmed in them (or the system could "record" a track into the system, creating an increasingly detailed feedback loop), so in a sense the system could anticipate different states well in advance. The road going systems don't have such luxury of course (at least not yet that I'm aware of even if nothing would prevent the development of "intelligent roads" communicating with the ECU) but rely more on sensors and thus are quite "myopic" by definition. My memory is a bit hazy on this, though, and part is purely extrapolation so if this is of interest, go and find out more by yourselves.

[MrT]

Active suspensions main advantages to my knoledge (I'm not an expert in the area) are;

1) You can effectivly have perfect damping as the damping co-efficient responds to the rate of wheel travel etc.

2) Ride rates (spring rates) can change depending upon what the suspension is doing. This allows ride heights, roll angles and rates, pitch rates etc to be controlled much more effectivly. Big aero advantages...

It should be noted that many of the road car suspension systems that are given the label active susension are actually only semi active, for example the Porsche suspension is not a fully active system like that which Williams implememented. Lotus put alot of research into the area, as well as active rear wheel steering which is another story

Read Alan Staniforths book on Competition Car Suspension - Good chapter on active suspension, rest of the book has some errors!

[Ian_E]

Why can the spokes of the wheels not be turned into vanes, then with a bit of Imagination..ok a lot of imagination and the right ducting pointed near to the ground as the wheels turned you could create a vacuum and suck the car to the ground.

Down side is this would use up power to create the vacuum, and the brake caliper cooling may go a bit haywire.

[Chubbs]

Why can the spokes of the wheels not be turned into vanes, then with a bit of Imagination..ok a lot of imagination and the right ducting pointed near to the ground as the wheels turned you could create a vacuum and suck the car to the ground.

Down side is this would use up power to create the vacuum, and the brake caliper cooling may go a bit haywire.

i think that idea would be banned as it is a moving aero part...

[Conceptual]

What about allowing active camber ONLY. Would that alone help the cars perform?

[modbaraban]

It is not allowed, but the answer is yes. While setting up camber you have to work out a compromise between extra lateral grip vital for cornering and longitudual for braking and traction.