Discovery 2 air suspension to spring conversion

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Interceptorxj said:
Not at all, if you wish to believe that it is an air suspension system on Citroens then so be it.
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I have never stated that there is 'air suspension'. I correctly stated that it isn't 'only' hydraulic.
Which it isn't...
I also stated that you are clearly the sort of person who think they are right regardless of the facts laid before them.
Thank you for confirming that!
 
Stanleysteamer said:
The gas in question is nitrogen, presumably used because air is 78% nitrogen, they called it "hydropneumatic" as "pneumatic" means "to do with air".
Your assertion that the gas filled spheres act as shock absorbers is wrong for two reasons.
Firstly, air or nitrogen is compressible and thus springy and this is where the springiness in this form of suspension comes from,
Secondly, shock absorption is a mixture of oil and air in that the oil is non-compressible and would thus simply transmit the shocks directly, not absorb them, but when the fluid is mixed with a gas it becomes partially compressible. Either by allowing the oil to pass through tiny holes into another air filled chamber, (conventional shocks) or into a sphere via leaf valves, under a diaphragm which has above it the compressible air/nitrogen.
In the first case the shock absorption is performed by normally allowing the oil to pass quickly one way but more slowly in the other. Adjustable shocks allow you to adjust the flow in one direction, or the other or both.
The spheres are not "gas filled" the top half is filled with gas the bottom half, under the membrane, is open to the hydraulic part of the system.
As the membranes in the spheres move constantly under compression and relaxation it is debatable that you could say they are moving parts or not!
see this
https://en.wikipedia.org/wiki/Hydropneumatic_suspension#:~:text=Suspension works by means of,and controls the suspension movements.
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The Citroen hydraulic system is fed via a swash plate pump driven off of the engine the system is pressurised to around 2000psi.

The Accumulator/spheres do act as shock absorbers, it has a butyl seal in the middle the uppermost portion is pressurised to around 75bar with Nitrogen the lowermost part of the sphere is filled with oil, the pump provides the pressure for each individual height, by allowing fluid pressure to act on this butyl diaphragm, which act's on pistons which raises and lowers the vehicle to the desired height..

Being that the Citroen system has no shock absorbers, found in the sphere itself is a venturi of a given size which gives them their "floaty" ride, it acts as a restriction for fluid passing in and out of the sphere.

A relatively simple system..
 
Henry_b said:
The Citroen hydraulic system is fed via a swash plate pump driven off of the engine the system is pressurised to around 2000psi.

The Accumulator/spheres do act as shock absorbers, it has a butyl seal in the middle the uppermost portion is pressurised to around 75bar with Nitrogen the lowermost part of the sphere is filled with oil, the pump provides the pressure for each individual height, by allowing fluid pressure to act on this butyl diaphragm, which act's on pistons which raises and lowers the vehicle to the desired height..

Being that the Citroen system has no shock absorbers, found in the sphere itself is a venturi of a given size which gives them their "floaty" ride, it acts as a restriction for fluid passing in and out of the sphere.

A relatively simple system..
Click to expand...
The link I put up explains this all pretty well. Dunno if I can be bothered to go on about this much more.
But just to finish up with, if a car does not have springs of some sort, the frame would bang painfully all over the place which would jolt the passengers teeth out and in the end shatter the frame.
If it had no shock absorbers, the springs would carry on bouncing the vehicle all over the place leading to loss of control and still much discomfort ,also the bigger bumps and potholes would lead to axles hitting the frame and doing the same as above.
So all systems have to have both.
And I still assert that in these systems, the springs are the compressed nitrogen because never mind how much it is sompressed, it still has some springiness in it. Think of air springs on the backs of 7 seater Disco 2s.
LFM is not compressible, or if so, only to a tiny extent, so it is used to transmit the shocks from the road around the system and to act as shockabsorbing which you explained very well.
The venturi you mentioned are called "leaves" by the Froggichops! But are only the same really as in any shockabsorber, tiny holes that let the fluid through but at a slow rate.
My final word on it!:)
 
Stanleysteamer said:
The link I put up explains this all pretty well. Dunno if I can be bothered to go on about this much more.
But just to finish up with, if a car does not have springs of some sort, the frame would bang painfully all over the place which would jolt the passengers teeth out and in the end shatter the frame.
If it had no shock absorbers, the springs would carry on bouncing the vehicle all over the place leading to loss of control and still much discomfort ,also the bigger bumps and potholes would lead to axles hitting the frame and doing the same as above.
So all systems have to have both.
And I still assert that in these systems, the springs are the compressed nitrogen because never mind how much it is sompressed, it still has some springiness in it. Think of air springs on the backs of 7 seater Disco 2s.
LFM is not compressible, or if so, only to a tiny extent, so it is used to transmit the shocks from the road around the system and to act as shockabsorbing which you explained very well.
The venturi you mentioned are called "leaves" by the Froggichops! But are only the same really as in any shockabsorber, tiny holes that let the fluid through but at a slow rate.
My final word on it!:)
Click to expand...
They wrote a song about 'em...

 
Stanleysteamer said:
Bad translation from the original which in fact means "Dead leaves", lol! And the translation of the rest of the song ain't much better! (Original is much sexier!)
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I thought Edith's WAS the original? I've heard several and i have to be honest, none i've heard beat her version, that said, Yves Montand does a passable copy :)
 
yfo866 said:
I thought Edith's WAS the original? I've heard several and i have to be honest, none i've heard beat her version, that said, Yves Montand does a passable copy :)
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No she does/did belt a song out.
https://en.wikipedia.org/wiki/Joseph_Kosma wrote the tune. English lyrics by Johnny Mercer, that famous translator and linguist!:rolleyes::rolleyes::rolleyes:
Original lyrics by Jacques Prévert, famous poet.
French film had its heyday during the war, which tells us quite a bit about what went on in Paris during the occupation.
Just finished reading a fascinationg book, "Les Parisiennes" by Anne Sebba. It is in english and very detailed. For instance I never knew that de Gaulle's niece, Genevieve, was imprisoned and survived Ravensbruck. 387 pages long not counting notes and index. After reading it you will be pushed to find a perfume house you would want to buy perfume from, if you want to avoid one that collaborated in some way!
And Coco Chanel should have been hung! (She very nearly was!)
On the other hand I have discovered Maurice Chevalier's behaviour was not as bad as previously thought and he didn't really deserve the bad press he got later.
The Duke of Windsor though... (Where is the puke imoji?!)
 
sierrafery said:
IMO removing EGRs and CATs are improvements not downgrades cos the engine runs better and cleaner without them while nobody can say sincerely that the ride is better on coils than on air... eventually some will say that it's the same even though the self levelling, off-road mode and extended modes are missing... also the self levelling is not only for towing, it has to do with load carying too, put 3 heavy guys on the back seat and fill the boot with sandstone to the accepted limit in one on coils and other on air then compare how they look, the SLS can accept 200kg more on the rear

View attachment 169852
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hi im a new member, im intrigued by your table of TD5 axle and vehicle weights. there is a note on the bottom which says that the max rear axle load can be increased to 1928kg if speed restricted to 60mph.. How does that work legally if you get stopped by vosa. Do you need to have a speed limiter fitted and a new vehicle / chassis plate?? thanks
 
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