Who had the idea?

This is the place for posts that don't fit into any other category.

Moderator: RichardW

Post Reply
j_roc
Posts: 230
Joined: 01 May 2005, 01:04
Location:
My Cars:

Who had the idea?

Post by j_roc »

I was sat in my garden and was looking at the Xantia, thinking about the hydropneumatic suspension. What I was wondering, not knowing much about it, was who designed it? Where did the idea come from? and, well why did they pursue such a complex design in the 1950's? Educate me on this and ill be much appreciated.
User avatar
CitroJim
A very naughty boy
Posts: 49518
Joined: 30 Apr 2005, 23:33
Location: Paggers
My Cars: Bluebell the AX, Polly the C3 Picasso, Pix the Nissan Pixo, Propel the duathlon bike, TCR Pro the road bike and Fuji the TT bike...
x 6156
Contact:

Post by CitroJim »

Well, the legendary state of French roads had a bit to do with it I guess. Certainly if the tale of the 2CV design brief was to be able to carry a basket of eggs across a ploughed field is true!
In the early 50's Citroen had a policy of very free thinking on all matters of car design and allowed their top designers to go off in quite advanced ways and this was the result of one of them. The Hydropneumatic suspension was developed on the Traction Avant and was available, on the rear only, on late Tractions.
It was of course seen first on all four wheels, steering, brakes and gearchange on the 1955 DS.
I think I'm right in saying that the same person designed both the 2CV and the DS. Shows what a bit of free thinking can come up with..
Quite where the original Hydropneumatic idea came from history does not record.
Stinkwheel
Posts: 562
Joined: 28 May 2004, 01:02
Location:
My Cars:
x 1

Post by Stinkwheel »

Also available on the rear of some H vans, to accomodate very heavy loads.
jeremy
Posts: 3959
Joined: 20 Oct 2002, 16:00
Location: Hampshire, UK
My Cars:
x 2

Post by jeremy »

Remember that after the 2nd World War France was largely wrecked and the roads were atrocious. Many certainly were in the late 60's and I have memories of just how incompetent the suspension was on the family Rover 3 litre from a holiday in Brittany.
Tha aircraft industry had begun to use hydraulics for undercarriage and later for controls on large planes to provide a means of operating ever larger control surfaces at greater distances from the pilot. Hydraulics were also being used for transmissions (GM pioneered a torque converter only transmission in 1948 or something but the 4 speed hydramatic was available in the early 50's followed by the 3 speed BW and others. BW was being fitted by Jaguar from 1955 or so.
So by 50's there's lots of general Motor trade interest in Hydraulics and spme interest in pneumatic suspension as well - Mercedes - early 60's and some Americans,
In reality the Citroen is similar to air but instead of compresing the air and using a conventional linkage they capture the air and use a hydraulic linkage which probably makes for a much more compact system and makes control more comprehensive.
The interesting thing is that the 2CV is linked for and aft and the only other Citren besides 2CV derivatives to have this feature is the cuurent Citroen rally car. BMC used for and aft linking on the 1100 etc but seem to have been the only others to do so.
As for complication - have a look at the DS with clutch and gearchange control etc. I think Citroen thought that this was the way to go but autoboxes took over and this was dropped.
jeremy
j_roc
Posts: 230
Joined: 01 May 2005, 01:04
Location:
My Cars:

Post by j_roc »

So, it was designed as more of a necessity than say, a group of engineers brainstorming. Due to the state of the French roads. You mention the H van??? Is that the van that has corrigated sheet panels and front wheel drive? Any idea of the pioneer/designer? Thanks to - Jeremy, Stinkwheel and Citrojim, im off on the net to have a search for more info.
paranoid
Posts: 770
Joined: 08 Jan 2004, 18:32
Location: United Kingdom
My Cars:

Post by paranoid »

lots of stuff if you follow the highlights!
http://en.wikipedia.org/wiki/Hydropneumatic
User avatar
Kowalski
Posts: 2557
Joined: 15 Oct 2003, 17:41
Location: North East, United Kingdom
My Cars: Ex 05 C5 2.0 HDI Exclusive 145k
Ex 97 Xantia 1.9TD SX 144k
Ex 94 Xantia Dimension 1.9TD 199k

Post by Kowalski »

"The whole high pressure part of the system is manufactured without any seals" "The only plastic/rubber parts are return tubes"
My Xantia certainly has seals, and there are rubber hoses in a couple of places, in fact there is even a hydraulic hose that takes full system pressure.
"Spheres originally used to have a valve on top"
Did they? I've seen older spheres where you could unscrew them to get the membrane out but I've never seen spheres with a valve.
bxbodger
Posts: 1455
Joined: 23 May 2003, 03:34
Location: Lovejoy country (Essex!!)
My Cars:
x 1

Post by bxbodger »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">The only plastic/rubber parts are return tubes"
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Yes, whoever wrote that article obviously didn't notice the front brake hoses!!!
They were a bit ill informed on hydragas as well, claiming that it was only fully refined on the Metro!!! er,,,,no front to rear connectivity,,,,and did they never ride in a Princess???
yangreen
Posts: 381
Joined: 25 Jan 2005, 14:11
Location:
My Cars:
Contact:

Post by yangreen »

I thought the Metro did have interconnected on the Metro? Might not the original but I think the 1990 re-design did. Could be wrong though!
406 V6
Posts: 593
Joined: 02 Sep 2004, 01:52
Location: Lisboa, Portugal
My Cars:

Post by 406 V6 »

The hydraulics were devised by a self-taught employee from Mr. André Citroën (it wasn't André Lefebvre...) as early as the 1930's just after the launch of the TA, when it's successor began to me planned.
Let me try and find a magazine that has a complete history on the hydro suspension.
That link in wikipedia has many wrong ideas:
The CX wasn't the first to have direccional high-beams, the 1964 DS was (with the facelift) and the C5 doesen't have a combined pump/sphere per wheel, but and electrically operated integrated unit comprising the accumulator, pump, valves and filters.
I'll get back to this, ok?
bxbodger
Posts: 1455
Joined: 23 May 2003, 03:34
Location: Lovejoy country (Essex!!)
My Cars:
x 1

Post by bxbodger »

The original Metro only got side to side connectivity, rather than front to rear, which completely defeated the object of giving the car a smooth level ride!!
Alex Moulton had his personal Metro connected front to rear to show BL management what they were missing and what they did wrong. It took them until 1990 and the new Metro to do it!!!
j_roc
Posts: 230
Joined: 01 May 2005, 01:04
Location:
My Cars:

Post by j_roc »

More info, slowly I start to see things clearer on hydropneumatic suspension. I never thought to go have a look on Wikipedia (a encyclopedia for those not in the know). I always knew about the BL Metro and its N/S to O/S interconnection Hydragas, Moulton actually pleaded with BL to connect the system front to rear but the "management" knew best....You would have thought that the Princess and it's predecessor sister the Maxi would have taught them that. I thank you all - citrojim, stinkwheel, jeremy, paranoid, kowalski, bxbodger, yangreen and 406 v6 for taking the time to educate a poor Welsh fool [:)].
406 V6
Posts: 593
Joined: 02 Sep 2004, 01:52
Location: Lisboa, Portugal
My Cars:

Post by 406 V6 »

Let's go back in time:
In the middle of the '30s (the TA was launched in 1934), the idea of the TA's sucessor started to take shpae.
Coded VGD (Voiture à Grande Diffusion - high production volume vehicle, more or less) this car was meant to be launched in the '40s, but due to WWII, it was delayed 15 years.
By now, you must all figured out the vehicle's name: the DS.
André Lefèbvre, a brilliant former enginneer from the car company of Gabriel Voisin, after spending 2 years in Renault after the 1929 financial crisis, and by Voisin's appointment, started to work for André Citroën. Lefèbvre was an aerodynamic man by excellence, as the car's shape with it's less wind resistance meant better fuel economy and small capacity engines for the same speed.
Along with Flaminio Bertoni, the designer, and Jean Pierre Boulanger - who became the, as we call them nowadays - CEO of Automobiles Citroën - after Pierre Michelin's death (who bought the company after André died - gee, let's stop talking about death, shall we?) - Paul Magés, tenderly called "the Professor" started with Citroën with 17 y.o., dedicated worker and self-taught man, with his simplicity devised the hydropneumatic system.
Even during german occupation, when the factories were not allowed to produce any car, he continued the development of the suspension secretly.
By 1942, Magés - expert in hydraulic braking systems - had this idea of substituting the standard springs with pneumatic elements.
A very crude system was tryed in April 1944 in a 2CV prototype and in June 1945 the system was considered reliable enough for production.
In 1949, the system was adapted to a TA and shown to Boulanger who agreed with it.
1953 saw the the TA 15-6H, with a rear hydropneumatic suspension, to be surpassed 2 years later by the DS.
And the rest is - as they say - history! [:D]
Stinkwheel
Posts: 562
Joined: 28 May 2004, 01:02
Location:
My Cars:
x 1

Post by Stinkwheel »

glad to be of serice :-)
When you actually look at it, the simple hydropneumatic system as fitted to say the GS and GSA (without any funny auto boxes, power steering etc) Its a very simple system and is infinitly easier and cheaper to produce, i should imagine, than a conventional springing setup.
jeremy
Posts: 3959
Joined: 20 Oct 2002, 16:00
Location: Hampshire, UK
My Cars:
x 2

Post by jeremy »

The great advantage of the system which is not as important today with good roads is that it can function optimally over a relatively short travel. Picture a conventional car with a single small driver riding in it. Then picture the car with the previous drivers overweight husband and his similarily built family in it and of course its sunk a considerable distance. The suspension has to provide a good and safe ride over a large range and of course is severely compromised in one or both states. Now if you could adjust that suspension so that it used the same travel for either load . . . - well we know the rest of the story.
Jeremy
Post Reply