DS 19 hydraulic circuit diagram with centrifugal regulator and separate brake return (SC 74424)

In this document

Cover page

A handwritten cover page bears the inscription in red felt-tip "Schema Hy DS" followed by the date "1960" in black ink p. 5. At the bottom right is a mention in black ink, of uncertain reading, "[Ach.] H. DS" p. 5.

The overall diagram

The following page presents a technical colour diagram entitled "CIRCUIT HYDRAULIQUE DS 19 AVEC RÉGULATEUR CENTRIFUGE ET RETOUR DE FREIN SÉPARÉ" p. 6.

A legend at the top right associates a colour with each function of the circuit:

p. 6

The diagram details the main components of the circuit: the high-pressure pump, the pressure regulator, the brake accumulator, the four suspension cylinders (front right/left, rear right/left), the front and rear height correctors, the front right and left braking blocks, the brake distributor, the hydraulic rack control with its control pinion, as well as the hydraulic brake control and the fast idle p. 6.

Several returns are explicitly named: "Retour du régulateur centrifuge", "Retour du bloc hydraulique", "Retour des correcteurs de hauteur", "Retour des cylindres de suspension" p. 6.

A set of labels in very small characters, in the frame at the top right, remains largely illegible; one can only distinguish, subject to uncertainty, the mentions "régulateur de 300", "coupleur de haute vitesse" and "correcteur de retransmission" p. 6 — these three elements cannot be held as certain.

The document bears the reference "SC 74424" at the bottom left, and a mention "1960" (of uncertain reading) at the bottom right p. 6. A short handwritten annotation, accompanied by an arrow, appears at the bottom centre of the diagram, near the front left braking block; its content (perhaps "Mod.") remains uncertain p. 6.

Context

The DS 19, presented by Citroën in 1955, remained famous for its hydropneumatic suspension, designed under the direction of the engineer Paul Magès. This system linked suspension, braking and power steering to the same central hydraulic circuit, powered by a high-pressure pump and regulated by a pressure regulator — all elements that are found by name on this diagram. The "centrifugal regulator" mentioned in the title probably refers to a device linked to the engine speed, a notion consistent with the research conducted at the time on the hydraulic assistance of the mechanical components of the DS.

Archivist's perspective

This document is likely an educational or technical summary diagram, intended to represent at a glance the entire hydraulic circuit of the DS 19, in a version where the brake return is separated from the general circuit — a detail that appears explicitly in the title p. 6.

The reference "SC 74424" and the date "1960" p. 5-6 place this document in the years immediately following the launch of the DS, a period during which Magès' hydraulic circuit continued to be refined and documented.

This overall diagram can be compared with more specific archives from the same collection, devoted to isolated parts of the braking system, such as the plan of the clutch cylinder D314-02 or the plan of the clutch control piston D 314-12, which detail components that this general diagram situates in the complete chain of the hydraulic circuit.