Distribution of Citroën hydraulic group activities among engineers (1960?)

In this document

Page 85 — List of technical projects

The sheet opens with a title: “List of hydraulic group activities 1960”, with a question mark drawn in red over the date p. 85, which suggests uncertainty about the year even at the time of writing or during a subsequent review.

Several technical projects are then listed:

• a self-regulating HP pump p. 85;
• a hydraulic motor broken down into electric generator, central fan, windshield wiper, each with its regulation function p. 85;
• a “Hydraulic supply” station associating accumulators and valves p. 85;
• the suspension, with sub-themes of the friction seal (synthetic oil / mineral oil), damping (current law towards new law, “Brint.”), and end-of-stroke damping p. 85;
• anti-pitch (acceleration and braking) and anti-roll (at 100% or by correction on bar) p. 85;
• a reflection on the “ideal sub-steering”, including for a truck p. 85.

The name Bourgeaud appears in red, associated with the suspension of a “Ford. land.” and the transition 2 CV to C p. 85.

Page 86 — Distribution by engineer

A list of names assigns each subject to a manager: Le Gal (truck brake), Perrier (steering), Bandin (anti-roll/brake), Dascotte (suspension), Vivier (suspension), Merret (hydraulic motors), Bonnier (HP pump), Perineau and Prestrelle (Hydraulic Transmission, linked by a brace), and Viedre (DS improvement, associated with “C.R Centrifuge Emb”) p. 86.

Pages 87-88 — Braking and transmission

Page 87 details leads on braking: progressivity, torque control at the front, distributor-corrector according to load p. 87, as well as a mention “Mechanical Transmission – 1st) 30 hp” p. 87. A small sketch illustrates a jaw mechanism p. 87.

Page 88, very short, refers to pages 3-4 of an unidentified document for a declutching and gear shifting indicator p. 88.

Context

The Citroën hydraulic group, led by Paul Magès, is at the origin of the hydropneumatic suspension of the DS (1955) and its subsequent evolutions. The themes listed here — high-pressure pump, regulation, anti-pitch, anti-roll, hydraulic transmission — correspond to the major research areas of this department during the years following the launch of the DS.

The hydrostatic transmission, mentioned here in an embryonic form, will be the subject of well-documented developments in the following decades, particularly around the 2 CV, the GS, and then the “L” vehicle (see linked archives).

Archivist's perspective

This document appears to be an internal distribution note, probably intended to organize the work of a team of engineers around several ongoing innovations. The red question mark on the date “1960” p. 85 invites caution: it could have been added after the fact, during a review, to verify or challenge the dating.

The joint presence of suspension, braking, steering, and a very young “Hydraulic Transmission” p. 86-87 provides a rare glimpse of all the hydraulic group's projects at a given moment — probably at the very beginning of the research that would later lead to the detailed files found in the “Hydrostatic transmission 59-74” folder or in the 1964 B.E.A. notes.

The name Viedre, associated here with “DS improvement”, reminds us that the continuous improvement of the system already on the market remained, in parallel with new research, a constant concern of the group.