B.E.A. Meeting no. 42 (3 December 1958): development of the DS H.P. pump

In this document

These handwritten minutes relate to meeting no. 42 of the B.E.A. (Citroën's Automotive Design Office), held on 3 December 1958 at 10:00 a.m. in Mr. Cadian's office p. 275. Those mentioned as present are Messrs. Cadian, Chaland, Guyistant, Loris, [uncertain: "Magès"], Schuzot, Perrinsau, Boller and Poumpon p. 275.

Development of the DS H.P. pump

The discussion focuses on the high-pressure pump of the DS and its industrial teething troubles: assembly of seals between the liner and body, risk of seizing, running-in tests, and the question of the "return of the bulge" p. 275. Mr. Loris mentions a change of seal and forging tooling that reduced deformations p. 275.

The exchanges also address the adjustment of operating clearances: a pre-production batch was tested with a clearance of 2 to 5 microns, with a target of tightening towards 2 to 4 microns to limit efficiency losses at 5 microns p. 275. The inclined bearing is the subject of requests for detailed drawings from Mr. Magès, with a preload to be defined ("20 to 50g") p. 275. Tests with different balls ("M.N.", "M.G.") are envisaged p. 275.

Finally, the text notes that "proper operation of the pressure regulator would reduce the pump's term", with a test planned at the laboratory p. 275, then mentions on page 276 the role of the cut-out valve, a control that "slips", and a possibility of metallizing production cut-out valves, the modification of the current cut-out valve leaving "much hope" p. 276.

The question of the ID Coupe sealing

A second point deals with the sealing of the ID Coupe: possible presence of engine oil mixed with the fluid, to be checked according to the wear of the unit p. 276. Mr. Magès proposes a solution with a scraper, a washer, a spring and a fabric ring, deemed not perfect but "the safest" p. 276. Other avenues are cited: periodic draining of the fluid, reinforced sealing, and attention paid to USA standards for potential special equipment p. 276.

Context

This document belongs to the mass production period of the DS 19, launched in 1955, whose hydropneumatic suspension and its high-pressure circuit remained, at the end of the 1950s, a field of constant industrial adjustments. The B.E.A. (Automotive Design Office) was the body where engineers and manufacturing managers confronted the development problems encountered in the factory and in the field — this type of weekly or bimonthly report was common at Citroën at that time.

Archivist's perspective

These minutes, difficult to decipher in places, offer a rare glimpse into the collective work of industrial development around the H.P. pump of the DS, with Paul Magès in a position of technical authority: he is the one from whom drawings are requested, whose opinion carries the group's agreement on tests p. 275, and who himself proposes a concrete solution for the sealing of the ID Coupe p. 276.

It seems that this document illustrates well the post-launch phase of the DS, where the challenges are no longer those of the initial design but those, more discreet, of reliability in production — clearances of a few microns, quality of bearings, residual sealing. This type of archive usefully complements the Summary of folder 41-59, which lists the developments of the hydropneumatic suspension and the DS as a whole.