Citroën DS 142-09 Drawing — Idle control device (2nd speed), 28 March 1956

In this document

This is a dimensioned technical drawing, bearing the reference DS 142_09, dated 28.03.56 p. 1, issued by the Société Anonyme André Citroën ("Reproduction prohibited" notice, p. 1).

Designation and purpose

The title block specifies the designation: "Dispositif de commande de ralenti (2e régime)" (Idle control device (2nd speed)) p. 1. The drawing represents a hydraulic system comprising a valve/regulator body, a coil spring, a cylindrical body pierced with threaded ports, and a screwed fitting marked P1 p. 1.

Technical specifications

Two annotations provide precise assembly instructions: a part marked Ⓜ3, tightened to 0.4 mkg, must "ensure sealing for VF fluid" under a pressure P1 of 250 kg/cm² p. 1. Another part (DS 142.137) bears the note "must turn freely" p. 1.

Part numbering

The drawing references numerous numbered sub-elements: DS 142.132, .133, .135, .137, .138, .139, .140, .141, .143, .147, as well as marks 622 551, 4929 S and DS 142-95 p. 1.

Modification history

The modification block indicates: "Ⓜ1 redone 26 759", "Ⓜ2 19/8 27.326", "Ⓜ3 13/24; 34/14 30011" p. 1.

Approval block

The following names appear in the approval table: Guyétant, Pompon, Caneau, Nguyen S. (draughtsman, dated 28.3.56), as well as the initials M.T. and B.F.A. p. 1.

Context

This drawing concerns a sub-assembly of the suspension and hydraulic control system developed for the DS, presented by Citroën on 6 October 1955. The operating pressure mentioned (250 kg/cm²) corresponds, in general terms, to the order of magnitude of the high-pressure hydraulic circuits used on this type of vehicle, particularly for assistance and the regulation of mechanical functions — the "LHS" fluid (referred to here as "VF") being the characteristic fluid for these circuits at the time. These elements are part of general knowledge about the DS and are not stated as such in the document.

This 1956 drawing is in the direct continuity of Paul Magès' work on hydropneumatic suspension, the first drawings of which date back to 17 February 1944 (Plans for hydropneumatic suspension with differential interaction and...), and which continued with the 2 CV tests of 1946 (Notebook of the first tests of the 2 CV with hydropneumatic suspension) and then with the test of the 15-Six H in April 1954 (Test of the 15-Six H, ELV 412, by Paul Magès, 3-5 April 1954), before the presentation of the DS.

Archivist's perspective

This drawing illustrates the detailed design work carried out within the Citroën design offices regarding the hydraulic devices of the DS. The precision of the tightening and sealing tolerances, as well as the traceability of successive modifications (Ⓜ1, Ⓜ2, Ⓜ3), suggest an iterative adjustment process typical of the industrial development of the time p. 1.

The document does not explicitly mention Paul Magès, who at that date held the position of deputy head of Super-Control within the Citroën design office (Draft letter from Paul Magès to Mr. Sarre and maintenance plan of 11...); this "idle control" drawing linked to a hydraulic pressure system likely falls within the field of innovation he led within the company. This drawing would benefit from being compared with other documents from the same DS 142 series if they are preserved in the collection.