Handwritten comparative calculations for P1 1800/1975 cm³ and 220 SF six-cylinder engines

In this document

Page 5 — Comparison P1 1800/1975 cm³

The sheet presents a series of handwritten calculations contrasting two engine speeds. A first column mentions a speed of "6000" (crossed out) then "5500", with a value of "3.7 km/1000" crossed out, and a calculation resulting in "30.8/1000" (underlined and circled) "to do 167 at 5500" p. 5. An annotation indicates "+ 23.5%" with an arrow p. 5.

A second column concerns the P1 engine: "1800 cm³", with a mention "d 175 auxi" and a circled total of "1975" cm³ p. 5. The speeds "5000" (crossed out) then "4500" (circled) are indicated, associated with "37 km/1000" and a speed of "167 km/h" p. 5.

A pencil sketch appears at the bottom of the page: a circle with radiating lines annotated "6°" and "7°" (or "70"), crossed by a horizontal line with arrows — without an explicit legend to specify its purpose p. 5.

Page 6 — Technical data sheet for the 220 SF engine

This page describes the 220 SF engine: "6 cyl. - 1 overhead camshaft - Injection", bore/stroke "80 / 72.8 c" for a displacement of "2195 cm³", and a compression ratio "Ran.vol. 9.58" p. 6.

The torque and power data shown are:

A series of "Speed per 1000" (rpm probably) gives four successive values: 7.88 / 12.373 / 18.739 / 28.875, with no gear ratio unit specified in the transcription p. 6.

Context

The 220 SF engine corresponds, in Citroën's history, to a six-cylinder injection architecture studied during the 1960s-1970s, a period when Paul Magès and his design office teams explored several engine types in parallel with the development of the hydropneumatic suspension. The acronym "P1" designates, in the archives of this collection, an auxiliary or experimental engine mentioned in several contemporary notes dated April 1964.

These comparisons of displacement, engine speed and power are part of the usual procedures of an automotive design office: arbitrating between several candidate engine blocks for the same vehicle, by comparing maximum speed, torque and efficiency.

Archivist's perspective

This document appears to be a quick working note, in pencil and pen, intended to compare the quantified performance of two engines — the P1 and the 220 SF — probably with a view to a technical choice p. 5-6. The presence of erasures and circled values suggests a reasoning process in progress, rather than a definitive summary sheet.

The thematic proximity to other items in the same file, dated from the same period, reinforces this hypothesis: see in particular the meeting report "P1 Operation" of Friday, April 1, 1964 and the handwritten notes and curves on the power and scavenging of the P1 auxiliary engine, which likely document the same P1 engine mentioned here.

The sketch at the bottom of page 5, whose function is not explained in the text, could relate to an ignition or timing diagram, but this remains an unconfirmed assumption by the document.