Manifold
(pronounced man-uh-fohld)
(1) Of many kinds; numerous and varied:
(2) Having numerous different parts, elements,
features, forms, etc.
(3) A copy or facsimile, as of something written,
such as is made by manifolding (obsolete except in historic reference).
(4) Any thin, inexpensive paper for making carbon
copies on a typewriter (archaic).
(5) In internal combustion engines, the part (1) of
the exhaust system attached directly to the exhaust ports and (2) of the
induction system attached directly to the inlet ports.
(6) In mathematics, a topological space that locally
looks like the ordinary Euclidean space.
(7) The third stomach of a ruminant animal (an
omasum) (US (mostly south of the Mason-Dixon Line)), usually in the plural.
(8) In computer graphics, a polygon-mesh
representing the continuous closed surface of a solid object.
Pre 1000: From the Middle English adjective manifold
(many times, in multiplied number or quantity), from the West Saxon & Old
English manigfeald & manigfealde (monigfald was the Anglian variant) (various,
varied in appearance, complicated; numerous, abundant), the construct being manig (many) + feald (fold). From the
Proto-Germanic managafalþaz came the common
Germanic compound (the Middle High German manecvalt (manifold), the Icelandic margfaldr (multiple), the Old Frisian manichfald, the Middle Dutch menichvout
& menigvoudig (various), the
Danish mangefold (multiple), the German
mannigfalt, the Swedish mångfalt (diversity) and the Gothic managfalþs), it’s thought perhaps a
loan-translation of the Latin multiplex
(multiply; having many forms) and the Old English also had a verbal form, manigfealdian (to multiply, abound,
increase, extend), the meaning later extended to (the now obsolete) “make
multiple copies of by a single operation”.
The adverb manigfealdlice (in
various ways, manifoldly), was derived from the adjective.
The noun manifold was applied to the mechanical
device (“a pipe or chamber, usually of cast metal, with several outlets”) from
the mid-1850s and was a short-form (from engineer’s slang) of “manifold pipe”
which had been in use since 1845 which originally was applied to the types of
musical instruments mentioned in the Old Testament. The familiar use to describe the components
which are part of an internal combustion engine’s intake & exhaust systems dates
from 1904 and applied initially to the pipe between a carburetor and the
combustion chambers; the existence of exhaust manifolds was noted the following
year.
Among those first translating the Bible into English, manifold
was a popular word and few phrases more concisely encapsulate the Church’s view
of us than “manifold sins and wickedness”. In the Book
of Common Prayer (1549). the Church of England helpfully provided a general confession for those who knew
they were wicked sinners (and of presumably greater significance knew that God
knew) but had neither the time nor desire to list them all. Once uttered, it invited God’s forgiveness. The Book of Common Prayer became controversial within the more liberal factions of the Anglican communion because its more exacting demands were thought to be uninviting to a society which was changing while the Church was not. However, despite many revisions (including some regionally exclusive to parts of the old colonial empire), sins and wickedness remain manifold in most editions.
The General Confession from the Book of Common
Prayer (1662 edition)
Almighty
God, Father of our Lord Jesus Christ, maker of all things, judge of all men: We
acknowledge and bewail our manifold sins and wickedness, which we, from time to
time, most grievously have committed, by thought, word and deed, against thy
Divine Majesty, provoking most justly thy wrath and indignation against us.
We do
earnestly repent, and are heartily sorry for these our misdoings; the
remembrance of them is grievous unto us; the burden of them is intolerable.
Have mercy upon us, have mercy upon us, most merciful Father; for thy
Son our Lord Jesus Christ's sake, forgive us all that is past; and grant that
we may ever hereafter serve and please thee in newness of life, to the honour
and glory of thy name; through Jesus Christ our Lord. Amen.
The
Duesenberg manifolds
1935 Duesenberg Supercharged J (SJ) dual cowl phaeton with coachwork by LaGrande, the lines made more rakish still by the use of a Rollston V-shaped windshield.
The
Duesenberg Model J was admired for it power, exclusivity, speed and coachwork
but one aspect which always draws the eye of nerds is the exhaust
manifold. The look most associated with
the marquee is that with four flexible pipes emerging from the right side of
the bodywork, a motif used not only by Duesenberg’s corporate stablemates Cord
and Auburn but also, if less extravagantly, by Mercedes-Benz where it was a
feature of many of the supercharged cars of the 1920s and 1930s.
1935 Duesenberg Model J Special Speedster (SSJ)
The
official factory designation was always “Model J” and their documents referred
to the supercharged cars as the “Supercharged J” but the latter is known
universally as the SJ. The public imagination
was further stimulated in 1935 when a short wheelbase version of the SJ was
announced. The factory referred to it as
the “Special Speedster” but people preferred SSJ although it was a rare sight
as only two were produced before Duesenberg finally succumbed to the effects of
the Great Depression.
Of
manifold shapes and weaknesses
The original manifolds used with the Model J were a variety of eight-port (8-into-1 in motorcycle parlance) units made from monel (a high-strength alloy of nickel, and copper, blended with carbon, iron & manganese) which engineers called “sewer pipes” (in modern parlance they’re known also as “dump pipes”). In terms of fluid dynamics they were efficient but, cast in one piece they were prone to cracking as the torsional forces to which they were subject tended to find the weakest points so they were redesigned as two-piece units (4-into-1) which better distributed the loadings. This improved durability though the propensity for the cast monel to crack wasn’t wholly eliminated and the the eight-pipe design made difficult the installation of the vertically installed supercharger hardware, added to which the heat-soak from the manifold was undesirable so the system was redesigned to used siamesed ports which fed the distinctive four external exhausts.
Memel 8-into-1 "sewer-pipe" manifold on 1934 Duesenberg SJ with the centrally-mounted supercharger fitted between cylinders 4 & 5 (left), the two piece (2 x 4-into-2) monel sewer-pipe manifolds in 1934 Duesenberg J (centre) and 8-into-1 sewer-pipe emerging through the engine-compartment right-side panel (right). The use of the apple-green color for engine components was a signature feature of the brand.
The externally-routed pipe-work is regarded as one of the most charismatic features of the big Duesenbergs and still it’s associated by many with the presence of a supercharger but some of the SJs used the monel manifolds and, for the most flamboyant, the factory anyway offered the look as a retro-fit option for US$1000 (at a time when a new Ford V8 could be purchased for US$505). Because of the fragility of the monel pipes and the fashion for the external ducting, only a handful of supercharged cars with the original manifolds are thought to survive. To those who make a fetish of intricacy, the monel sewer-pipe manifolds are thought the most photogenic of all.
Manifold porn: Chrysler's Slant Six was an engine of modest specification and expectations but typical of the corporation in those days, the basic engineering was fundamentally sound and in a variety of displacements (170 cubic inch (2.8 litre, 1959-1969), 198 (3.2, 1970-1974) & 225 (3.7 1960-2000), it was produced between 1959-2000 making it one of the US industry's longest-serving powerplants. One unusual aspect of the Slant Six's design was the block was canted to the right at a 30o which meant there was much space available to the left and a range of intake manifolds followed, some of which remain available to this day. Using variations of the Sonoramic tuning, manifolds were produced for single, two & four barrel carburetors and between 1965-1968, Chrysler's Argentine operation produced the Slant Six in a version with twin single barrel carburetors. The use of the properties of fluid dynamics to gain power or torque as desired quickly was adopted by the industry as an engineering orthodoxy.
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