Note: Descriptions are shown in the official language in which they were submitted.
21 89968
Exhaust Ga~ ~Sanlfold or a Multl-Cyllnder Engine
The present invention relates to an exhaust gas manifold for a multi-
cylinder en~ine, whlch passes the exhaust gas of several cyllnders to
a common outlet, and ls made without any weld seam, in that lt is
formed rom a tube plece with at least one neck formed in the side
wall o the tube plece.
Such an exhaust gas manifold ls dlsclosed in the ~apanese patenl:
~l?plication 62-206216- In this known~exhaust gas manifold, two necks
are formed in the side wall of a straight tube piec~; these neclcs,
after having been provided with openings, s~rve as exhaust gas inlets
of the exhaust gas manifold. One oL t~le two open ends serves as the
outlet of the exhaust gas maniold.
In this exhaust gas manifold, it has proven to be a disadvantage that
lt is only suitab~e for bringing together the exhaust gas of adjacent
cylinders. It is unsuitable, for example, for bringing together the =
exhaust gas o cyllnders l and 4 of a four-cyllnder in-llne engine, as
is desirable or high-performance engines, to increase thelr
perormance; thls is because it would not be posslble to lnstall a
second exhaust gas manlfold which brings together the exhaust gas of
cylinders 2 and 3.
Furthermore, other tube junctions ormed in the most varied ways are
also known. For example, the German utility model 9100867 describes a
tube junction in which two tube segments which have been flatten~d on
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one side at the end and which rest against each other are inserted
into a larger ~tube. In the tube ~unction known ~rom the European
patent application 192995, a main tube has an incision into which the
end of another tube segment, which is formed accordingly, opens; ~he
tube segment is -~nnP~-tPd with the main tube by welding. The German
Offenlegungsschrift ~2283i2 describes a tube junction in which a tube
segment is inserte~l, at its end, into a neck which is mechanically
produced in a tube elbow. In all three known tube junctions, it is a
disadvantage that they are composed of two~or three separate par~s.
This results in signi~icant production costs. One of the reasons
these costs are so high is that the parts to be connected with each
other must fit precisely relative to one another, and must be aligned
correctly with one another, so that sufficient mechanical strength and
a leak-proo~ seal o:E the tube junction is guaranteed.
In exhaust gas manifDlds known ~rom car racing, which are formed as a
tube ~unction, a hole is cut in the outside wall~f a pre-bent tube,
generally using a laser cutter, and a correspondingly adapted tube is
welded into it. Such tube junctions suffer from the same
disadvantages as those described above.
Tube ~unctions produced i~rom two hal~ shells are also expensive to
produce, because of the long weld seams which connect the two half
shells with each other.
~nother tube junction is descri~ed in the German patent 4103083. This
known tube ~unction proceeds from a tube piece which has been
hydrostatically transformed, especially widened, a.d subsequently been
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converted to a double tube in certain regions, by being lndented. In
this known tube junction it i9 disadvantageous that the arrangement of
the two inlets cannot be freely selected; instead, the two inlet6 are
always very closely adjacent.
In the article "E~ydrostatic forming o~ tubing produces complex parts"
(57 Automation 10 (1963.06), p. 84/85), the method o~ hydrostatic
forming is explained in connection with different hollow elements, and
the formation o~ a neck in the wall of a bent tube piece is also
preeented .
The present invention is based on the task of creating a light, stable
exhaust gas manifold ~of the type stated initially, which can be easily
and inexpensively produced, in which the arrangement of the at least
two inlets can be selected in almost any way desired, relative to one
another. The background for this statement oi task is, in particular,
the available space for the installation of exhaust gas manifolds
structured as tube junctions in internal combustion engines, since
this space is often limited.
In accordance with the present invention, this task is acco~Tplished by
means of an exhaust gas mani~old for a multi-cylinder engine, which
passes the exhaust gas of several cylinders to a common outlet, and is
made without any weld seam, in that it is formed from a tube piece
with at least one neck formed in the side wall of the tube piece,
where the tube piece is bent in such a way that its two ends serve as
inlets, where the neck serves as a common outlet. The exhaust gas
manifold according to the present invention therefore consists of a
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single component. It is not necessary to ~oin to~ether several
components, in an expensive process, in order to produce the exhaust
gas manifold according to the invention. Accordingly, the latter also
does not hav~ any kind of weld seams or similar features. It is
therefore absolutely sealed; and there is no weakening of the material
due to weld seams. The exhaust gas manifold according to the
invention can there~ore also be produced from a material which is not
well suited or not at all suited for welding. Furthermore, the two
inlets formed by the ends of the tube piece can possess almost any
desired aLLC~ relative to one another, by bending the tube piece
accordingly. By making it po6sible to arrange the two inlets in any
desired way relative to one another, the invention particularly
permits making available an inexpensive, light exhaust gas manifold,
in which tbe exhaust gas of cylinders 1 and 4 of a four-cylinder in-
line engine, which are far apart ~rom one another, is brought
together. To produce an exhaust gas manifold according to the
invention with three or more inlets, it is practical if the inlets
over and above the two formed by the ends of the tube piece are formed
by necks formed in the side wall of the tube piece
"
The exhaust gas system of a four-cyiinder engine can comprise two
e;shaust gas manifolds according to the invention, each of which
combines two cylinders with one another - cylinders 1 and 4, i.e. 2
and 3 in the case of a four-cylinder in-line engine. ~owever, a
combination of a manifold according to the invention for cylinders 1
and 4 with one for cylinders 2 and 3 having a conventional structure
is also possible.
21 89968
s
In the sense of~ the present applicatlon, "tube" and '~tube segment" are
not understood to :mean only those with a clrcular cross-section.
Tubes or tube 6egments with different cross-sections (e.g rectangular,
oval, polygonal~ can also be used within the framework of the
invention. Furthermore, it is not precluded that the cross-section
changes over the length of the tube piece (e.g. widens, narrows, is
constricted in places).
To produce the exhaust gas manifold according to the invention, it is
practical if the neck which later serves as an outlet is introduced
into the tube piece by means of the method of interior high pressure
deformation (I~V) . It i8 especially preferred in this connection if
the tube piece is bent in such a way, before the neck is formed, that
its two ends which later serve as an inlet ~iave essentially their
final position reIative to one another, and if the progression of the
tube piece, between the subsequent inlets and the subse~uent outlet,
already corresponds to the final progression. For interior high
pressure deformation, such a pre-bent tube piece is then placed in a
forging die which has a first recess to hold the pre-bent tube piece,
as well as a second recess=which opens up into this first recess, in
its impression. During the process of interior high pressure
deformation, the tube piece is deformea lnto the second recess, in
order to form the outlet. It is practical in this connection if the
formation of the neck into the second recess o~ the forging die takes
place under the control of a counter-punch. The counter-punch
retracts in a defined manner, as the neck is formed in the second
recess. In this way, overly rapid formation of the neck, with a
correspondingl~ ~reat ~ecrea~;è in wall thickness, is avoided.
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Instead, the formation o the neck takes place so slowly, because of
the defined counter-force of the counter-punch, that the tuoe piece
can be followed up from one or both ends. For corresponding swaging
of the tube piece during interior high pressure deformation, at least
one axial punch which can be moved in the i~irst recess is provided,
which exerts an axiai force on the end of the tube segment assigned to
it, so that material flows into the deformation region of the neck.
~or the production of additional necks which can serve as additional
inlets, a corresponding number of: third recesses which open into the
first recess can be provided in the forging die.
A device suitable for production of the exhaust gas manifold according
to the invention has the following characteristics:
- A forging die has an impression with a ~irst recess to hold a
tube piece, and a second recess which opens into the first
reces 8;
- two axial punches are provided in the first recess, at least one
of which has a line bore to feed a pressure medium into the
i~terior of t~Q tube piece placed into the first recess; ~=
- a counter-punch which can be moved is located in the second
recess.
A significant characteristic of this device is therefore the counter-
punch provided in the second recess, which ensures controlled
formation of the neck during interior high pressure deformation, in
the manner descrlbed above and explained in greater detail below. ~he
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forging die consists o~ two or more mold parts, depending on the final
shape of the tuoe junction.
The retraction of the counter-punch as formation of the neck
progresses can take place against the force of a spring element.
Also, retraction of the counter-punch as a function of time or o~ th~
pressure prevailing inside the tube piece, controlled by means of a
corresponding aevice, is also possible.
It i8 practical if at least one of the two axial punches of the device
described is guidcd so that it can be moved in the first rece6s during
intérior high pressure deformation, so that the assigned end of the
tube piece can be ~ollowed up during interior high pressure
deformation, in accordance with the formation of the neck. A follow-
up device acts on this movable axial punch. This device can be path-
controlled, for example; this means that the axial punch is moved a
pre-determined path distance as a fixed function of the pressure
prevailing in the tuhe piece. Furthermore,~ force control is also
possible, in which a defined force swaging the tube piece is applied
to the axial punch. Furthermore, a combined path-force control can be
provided to move the axial punch. Finally, it i8 also possible to use
the escape path of the counter-punch or the force acting on it as the
input value for controlling the movement of the axial punch. Also,
the force acting on a punch can be controlled as the function of the
displacement path of any ~other~ punch; this holds true both for one
or both axial puncbes and for the counter-punch or counter-punches in
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the case oi several necks. Control o~ the movable punch(es) is not,
however, compul60ry.
In order to make the displacement movement of the counter-punch in the
~orging die possikle, the second recess preferably has a cylindrical
segment in which the counter-punch is guided. ~he same thing hold6
true for the first recess, iE one or both axial punches are 6upposed
to be movable, in order to be able to push in the end of the tube
piece assigned to them during the process o~ interior high pressure
deformation.
In the following, the invention will be explained in greater detail
using the drawings. These show:
Fig. 1 to ~: various btages ~uring the production oi an exemplary
embodiment of the exhaust gas mani~old according to the in~/ention, and
Fig. 5: a cross-section through a device suitable for~production oi
the exhaust gas manifold according to the invention.
A tube piece 1 (Fig~. 1) serves as the starting material i~or the
production of the exhaust gas manifold (Fig. 4) . The tube piece 1 is
bent in a known bending device, in such a way that its two ends 2, 3,
which are ~ n~n~ to form the inlets F of the ~inished tube ~unction
tFig. 4), take on practically their iinal posltion relative to one
another. In the pre-bent tube piece 1' (Fig. 2), the progression of
the tuke piece between the two ends also corretponds essentially to
the :Einal progressio .
21 8~968
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~he pre-bent tube piece 1' i8 now placed into the forging die of a
device in which the neck 4 (Fig. 3) is formed in the side wall of the
pre-bent tube segment 1'. For this purpose, the forging die has an
mpression with a first recess, which is adapted to the shape of the
pre-bent tube piece 1', and a second recess, into which the neck 4 is
supposed to be formed. ~o form the neck, the pre-bent tube plece 1'
i8 defQrmed by means Qf the method of interior high pressure
deformation. For this purpose, a pressure medium is introduced into
the tube piece, in known manner. As the pressure inside the tube
piece increases, it deforms in the region of the secQnd recess of the
forging die, forming the neck 4.
After thç tube piece 1'' (Fig. 3) was removed from the forging die,
after the process of lnterior high pressure deformation was completed,
the "cap" S of the neck 4 is cut of, 80 that the outlet A (Fig. 4~ of
the finished tube lunction is formed. Depending on ~urther use, the
inlet~ E and the outlet A of the tube iunction can be ~itted with
flanges after the~ deformation process is finished.
Fig. ~; illustrates the iorging die C: of a device in which interiQr
high pres~ure deformation of a tube piece to i~orm a neck takes place.
In the left ha~ o~ Fi~. 5, the ~e-/ice i~ oh~ bee~r~ the ~t~rt o~
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deformation of the tube piece, while it is 6hown at the end of the
deformation proce6s in the right haif. - ~ -
The forging~ die 6hown in Fi~. 5 6erve6 for~deformation of a 6traight,not pre-bent tube piece 1. Accordingly, the fir6t rece66 6 i6
6tructured to be 6traight. Within it, two axial punches 7 are guided
to move in it9 longitudinal direction. They each posses6 a bore 8,
one of which 6erve6 to feed a pre66ure medium 9 into the tube piece 1,
and the other of which 6erve6 for 6imultaneou6 ventilation. The axial
punches 7 form a tight seal with the assigned end6 of the tube piece
1, by mqan6 of a corre6pondingly 6tructured 6ealing surface 10
.
The 6econd rece66 11 open6 into the fir6t rece66 6. The counter-punch
12 i6 guided to move in the for~er. ~ 6pring element - not 6hown -
acts on the counter-punch 12, placing pres6ure on the counter-punch in
the direction of the tube piece 1 placed in the first reces6 6.
If the pre6sure medium 9 inside the tube piece 1 i6 placed under
su:Eficiently high pressure, the out6ide wall of the tube piece 1
deform6 into the 6econd rece6s 11, so that the neck 4 i6 formed there.
If deformation of the tube piece has progre6sed 60 i~ar that the wall
of the tube piece 1 rests against the face 13 of the counter-punch 12,
the counter-punch 12 is shifted as the deformation continues, against
the force of the spring acting on it. In other words, the neck ~,
which con6tantly enlarge6 during the process of interior high pre66ure
deformation, pushe6 the counter-punch 12 ahead of it6elf. Because of
the counter-force acting on the counter-punch, the result achieved i6
that the deformation takes place 610wly; thls means that sueficient
21 899~8
materlal cau flow into the (~r ~nrr~7tion region bec~use Qf the follow-up
produced by the axial~ punches ', . The fQlLow-up of tlle axiàl punches 7,
takes place by means of a separate follow-up device, not shown. A
defined follow-up force is applied tQ both axial punches by means of
'hig device, a~ ~ funcCi~n oi ~he p~essure ~f ~ re~ure ~dism 9
i.
