Outer Limits 4x4 Board

was reading some old overlander mags today about 96 ish. and they did a write up about this WA based company called kinetix who make this penumatic/hydrolic suspension that replaces the coild and shock and ofers huge travel.

does anyone know if they r still around, or what hapened to them.

You betchya - new 200 series cruiser has it. Looks brilliant on paper.

It reminded me of the topic where forced articulation was discussed.

Does anyone know if anyone has built a hydraulically linked system to diagonally link wheels? Seems like the way to go. It's like having diagonal swaybars.

Paul

yes, Soni Hioneger (spelling) and his Scorpion buggy had a diagonally linked. forced articulation system

grimbo wrote:yes, Soni Hioneger (spelling) and his Scorpion buggy had a diagonally linked. forced articulation system

That was mechanical from what I read. This is much simpler (kinda) hydraulic. I'm still nutting the details in my head. I think the articulation control circuit would have to be seperate from the ride height / spring circuit, but makes sense.

The scorpion linked the axles via torsion bars mounted longitudinally. This still allows some "spring" in the system to make it work functionally.

The current range rover diagonally links its airbags when in low range.

Hydraulics are tough because A) there is no "give" like with bags or torsion bars and B) because the rate of fluid transfer has to be very fast to get the system to not start to work against you when you get on he throttle.

Air actuators would be better in this regard. There are some guys in the US "air ride" on pirate I think) is still playing with air actuators to force articulation.

At the beginning of rock crawling competition, all sort sof stuff like this was being tried, but it has kind of petered out - I think whilst it works in some situations, it works against the driver in others.

Steve.

It was tried on here as well but that member drove through the first layer of gravity and hasn't been seen since.

The current self levelling rear of the 100's uses a similar principle system. The springs are tiny thin things, doing only 30% of work at a guess. The shocks are quite large, but normal looking. Buried up there somewhere (I was layin on Motorama showroom floor to look, kinda difficult) is a thin hydraulic line. The other end goes to a vavle body under the sill with a metal bubble on it - about 1L in size. I would asume this is a hydraulic accumualator with gas pressure and prob some type of diaphragm. No electrics here, it's valving only.
There is a hydraulic pump under bonnet with resovoir. A height sensor (arm + pot) in middle of diff works out average ride height and tells the pump to "top up" or "bleed off" fluid from the system.

Bascially the rear suspension is 80% air over hydraulic like the citroens used to be.

The Kinematic system on the website looks similar, with some nifty crosslinking. My mental thinking of the flow requires seperate circuits for "support" vs "interconnect" - but there may be an engineering trick aroudn this.

Paul

Gwagensteve wrote: Hydraulics are tough because A) there is no "give" like with bags or torsion bars and B) because the rate of fluid transfer has to be very fast to get the system to not start to work against you when you get on he throttle.

If you mount the hydraulics in series with the springs you can get around that.

there was an article in 4wdm with a guy in a rangie/disco contraption. he used a transfer case to drive the opposite axle in the opposite direction (angle) so when the front dipped left the rear was forced to dip right.

ausoops wrote:there was an article in 4wdm with a guy in a rangie/disco contraption. he used a transfer case to drive the opposite axle in the opposite direction (angle) so when the front dipped left the rear was forced to dip right.

That was the one we discussed in another thread. To my looking the kinematics system is a hydraulic version of the same thing, and with some other nifty tricks.

Their website says it's just been written out of the rulebook for both WRC and Paris to Dakar as an unfair advantage (reading between the lines - prob due to exclusive contracts). Seemed to be keeping the wheels down based on who won.

Interestingly if like the current 100 series cruiser - the solid lines are thin, only a bit bigger than brake lines and not as big as an AC line. I would have thought the fluid movement even for the piston shaft would need more than that, so there is more than meets the eye here. Also a shock piston is designed to have fluid flow past / through it. If used to support vehicle weight it will leak down pretty damn quick. Either thereis a second piston in there, or they are using the shaft displacement as an equivalent (nifty) but I woudl hate to think of the pressures involved.
20mm guess shaft diam - 1 ton rear weight/2 shocks
pi r sqr = 314 sqmm = 0.54 sq inch
1100lb / 0.54 = 2037lb/sq inch
That's within the realms of normal for hydraulics I guess. I wonder if the accumaltor runs at a lower pressure and runs a small diamter hydraulic piston to transfer the pressures to a diaphragm - that would be really tricky - might explain the vavle block size. The accumualtor chamber looked like pressed steel, not rated up to 2000PSI.
Full stroke (250mm guess) equates to aprox 78.5cc's of oil, not much really.
If a full stroke on a big hole at speed was 0.1sec that equates to 46.8l/min - seems like a very high flow rate for the lines I saw.

Paul


Paul