Hydraulics Quiz No. 2 (second copy): pressure source and accumulator

Second copy of a Citroën educational questionnaire on the high-pressure pump, the pressure regulator and the main accumulator, supplemented by a volume calculation exercise based on the law P×V = cte.

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Understanding this document

In this document

This document is the second copy of the Hydraulics Quiz No. 2, presented as "the second of the six Hydraulics quizzes" p. 26. The questionnaire was to be "returned no later than fifteen days following receipt" p. 26, with a telephone and fax number for contact p. 26.

Questions on the pressure source

Questions 1 to 8 cover the operation of hydraulic components, the high-pressure pump "at rest", hydraulic reservoir pressure, level checking, and the intake/compression cycle in "a 5-piston pump" via the delivery valve and the swash plate p. 26.

The pressure regulator and the main accumulator

Questions 9 to 14 deal with the pressure regulator (conjoncteur-disjoncteur), which sets a pressure (min/constant/max), the cut-out linked to a pressure in the accumulator, and the structure of the main accumulator: a deformable membrane separating "a compressible gas and an incompressible liquid" among the proposals p. 26-27.

Calculation exercise

A guided example calculates the volume of liquid in a sphere at 145 bar based on the law P x V = cte, with a charging pressure of 62 bar and an empty volume of 400 cm³, resulting in "400-171 = 229 cm³" p. 27.

The "Your turn" exercise asks to redo this calculation for a 250 cm³ sphere, charging pressure 30 bar, at 170 bar, with multiple-choice answer proposals p. 27.

Element	Example (145 bar)	Your turn (170 bar)	Page
Charging pressure	62 bar	30 bar	p. 27
Empty volume	400 cm³	250 cm³	p. 27
Constant (P×V)	24,800	15a/15b/15c (to be found)	p. 27
Calculated gas volume	171 cm³	16a/16b/16c (to be found)	p. 27
Liquid volume	229 cm³	17a/17b/17c (to be found)	p. 27

The document ends with a space for remarks, work time, signature and date, with the mention "Keep the carbon copy" p. 27.

Context

The pressure regulator and the main accumulator are central components of the hydropneumatic system developed by Paul Magès for Citroën, allowing the regulation of the high-pressure circuit (traditionally around 145-170 bar on vehicles like the DS) and supplying the suspension, brakes and power steering. This technical vocabulary, outside the document, corresponds to notions well known to enthusiasts of the brand.

This pedagogy through quizzes and numerical exercises is likely part of the distance learning system of the "Hydraulics Expert Notebooks" mentioned in other documents in the same collection.

Archivist's view

This second copy of quiz no. 2 confirms, like its duplicate, the pedagogical rigor of the system: multiple-choice questions followed by a progressive calculation exercise, from the guided example to the numerical application p. 27. It seems that the existence of two almost identical copies of the same quiz reflects either distribution to several trainees, or the keeping of a copy before sending, in accordance with the mention "Keep the carbon copy" p. 27.

This document usefully complements the Welcome booklet "Welcome... The keys to your success" and is part of the same series as the Hydraulics Quiz No. 1, devoted to pressure basics and the braking circuit, together forming a progressive learning path for Citroën hydraulics.