Oil reservoir sketch: needle, seals and mounting

In this document

The sketch, titled "Reservoir" p. 6, shows a cross-section of an oil reservoir equipped with a top filler cap (marked C), a spring (B), and a needle (A) resting on its seat at the bottom. The arrows in the drawing indicate air and oil circulation at several levels of the reservoir p. 6.

An annotation specifies that the reservoir mounting "can be provided on the cylinder head cover or this can itself form a reservoir", and that it "can also be fixed to the hull" p. 6 — Magès therefore envisages several possible locations for the part.

The principle explained in "Nota"

The handwritten text at the bottom of the page constitutes the functional explanation of the system: "the needle A must rest on its seat before the spring B is completely released, when removing the cap C, so that the oil contained in the reservoir does not flow into the lower crankcase due to the entry of air through the upper opening during filling" p. 6.

In other words, the document describes an anti-leak device: the closing of the needle must precede the complete decompression of the spring at the moment the cap is removed to top up the oil.

Context

This type of oil reservoir with a needle and spring closing system evokes, in a general way, the research conducted at Citroën on lubrication and level control of engines and hydraulic systems during the decades when Paul Magès developed his inventions, particularly around the hydropneumatic suspension. These issues of fluid level control (oil, air) are central to the history of Citroën engineering from the interwar period to the post-war period, although this specific document does not allow for further dating or locating of the intended application.

Archivist's perspective

The care taken in describing the mechanism — and in particular the sequencing logic between the needle and the spring — suggests that this is a well-developed technical reflection, probably intended to avoid a known defect (oil leakage during filling). However, the document bears no date or part reference, which invites caution regarding its precise attribution.

This sketch is part of a family of documents concerning oil management in mechanisms designed by Magès: it can be compared to the dimensioned sketch of the hydropneumatic oil level reservoir and the proposal for a constant oil level system for engine crankcase, which testify to a recurring concern for the reliability of lubrication devices.