Hydraulics Quiz No. 5 (second copy) — DIRASS, DIRAVI and flow rates

In this document

This document is a second copy of the Hydraulics Quiz No. 5, a questionnaire to be returned "no later than fifteen days after receipt" p. 16, presented as "the fifth of the six Hydraulics quizzes" p. 16.

Multiple-choice questions (p. 16)

The first ten questions cover:

• the respective functions of DIRASS and DIRAVI (assistance, hardening according to speed, steering return control — questions 1 and 2);
• the components of a DIRASS steering circuit, including the pressure regulator, the cylinder, the priority valve, the rotary valve, the front height corrector (question 3);
• the "pressure-based" or "flow-based" operation of the suspension and DIRASS (questions 4 and 5);
• the fluid pumping mode in a DIRASS (question 6);
• the flow distribution by the flow distributor between the reservoir, steering circuit and main circuit, in the "conjunction" and "disjunction" phases (questions 7 and 8);
• the variations in flow and pressure in the steering circuit depending on whether the vehicle is driving in a straight line or turning (questions 9 and 10).

Exercises (p. 17)

Exercise 11 asks to indicate, on a hydraulic diagram (steering rack, "RD", "HP", "CD", "AC", "R", "VP" blocks), the direction of six arrows A to F representing fluid circulation in the disjunction phase.

Exercise 12 proposes a table to be filled in, linking components (assistance cylinder, TC distributor, cam/roller system, variable flow regulator, centrifugal regulator, TR distributor) to the three functions: assistance / speed-dependent hardening / steering return control.

The page ends with a space for "Your comments regarding this chapter", a field for "Time required to study this module", a signature, a place and a date to be filled in, as well as the instruction "Keep the carbon copy" p. 17.

Context

This quiz belongs, like the previous copy already archived, to the Les Cahiers Experts de l'Hydraulique training course provided by the CIFC (Centre) in the 1990s, intended to internally transmit the hydraulic knowledge developed by Citroën under the impetus of Paul Magès.

DIRASS (power steering) and DIRAVI (power-assisted steering with return control) designate, in Citroën technical vocabulary, two generations of hydraulic power steering systems equipping in particular the DS then the SM and the CX — the second integrating a speed-dependent steering return control, unlike the first.

Archivist's perspective

This is a duplicate of the questionnaire already described under the title Hydraulics Quiz No. 5 — DIRASS, DIRAVI and pressure regulator, reproducing identically the ten multiple-choice questions, the hydraulic diagram arrow exercise and the component/function correspondence table p. 16-17.

This second copy, free of any annotation unlike the other, probably illustrates the "carbon copy" principle mentioned at the bottom of the page p. 17: one copy to keep, the other to return completed. It is part of the broader educational series described in the presentation of the CIFC training, alongside quizzes No. 1, 2 and 6 already archived.

This document does not bear a precise date; the attribution to the 1990s is based on the context of the CIFC training, not on an explicit mention in the text.