Note: Descriptions are shown in the official language in which they were submitted.
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The present inven-tion relates to improvements in
an air cooled, reciprocating piston, internal combustion
engine having at least one row of cylinders and individual
cylinder heads arranged side by side, the cylinder heads
being substantially cube-shaped exteriorly and provided with
means such as bosses, for accommoda-ting a-ttachment bolts.
The cylinder heads each having at least one inlet valve and
one exhaust valve, the valve stems of which extend sub-
stantially parallel to the axes of the cylinders, and situtated
such that the plane passing through the valve stems lies at
an acute angle to the longitudinal direction of the internal
combustion engine, the cylinder heads each including an
intake duct, located on a side thereof swept by the cooling sir,
the intake duct having its opening located approximately
centrally of the cylinder head, the cylinder heads each including
an exhaust duct extending substantially perpendicularly to the
exhaust air or exit side, and a lateral deflector being
provided adjacent the last or end cylinder head in each row.
An air cooled, reciprocating piston, internal com-
bustion engine of this type, having corresponding single
cylinder heads, is known from commercial engine series 924
to 930 of the Tatra-Werke, Czechoslovakia, it being illustrated
and described in the technical publication entitled, "Air
Cooled Automobile Engines", by J. Mackerle, ~rank'sche
~erlagsbuchhandlung, Stuttgart, 1964, reference pages 171 to
173 and 524 to 528. The design of the cylinder heads and
cooling ribs is such that each cylinder head constitutes
a coo]ing unit per se through which air flows in substantially
straight lines. Thus one cylinder head, and its associa-ted
lateral deflectors, forms merely a restriction for the flow
of air to the o-ther cylinder head. A reciprocating piston
internal combustion engine, and a cyl.inder head, of this latter
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kind are suitable only for limited ou-tputs, since the area
of the exhaust ducts, in particular, and the areas between
the exhaust duct and -the cy:linder barrel, cannot be adequately
cooled. This is also due to the fact that the bosses for
the cylinder head attachment bol-ts extend, in the crankcase,
to the upper edge of the cylinder head.
It is -therefore a main purpose of the present in-
vention to improve the air cooled reciprocating piston in-
ternal combustion engine in question, and the cylinder heads
and cooling thereof, in such a manner that higher outputs can
be aehieved, that the high strength of the cylinder head is
retained, that satisfactory guidance of the cooling air and
satisfactory cooling of hot spots is achieved, and that
production costs are favourable.
The aforementioned aim is aehieved in that, with the
aid of the external contours of the gas exchange ducts, in
eonjunetion with the eentral areas arranged between the res-
pective valve stems, and the cooling ribs extendiny at right
angles to the axis of the cylinder, the adjacently arranged
cylinder heads form one or more - depending upon the size of
the cooling ribs - arcuate or S-shaped cooling air ducts in
the cylinder head section facing away from the cylinder, and
in that the cover plate section - facing the cylinder - of
the cylinder head is provided with cooling ribs at the
periphery, substantially on the exhaust air side and on the
side facing the inlet valve s-tem, and comprises bosses for
accor~nodating at-tachment bolts. Although the cylinder head
according -to the present invention is in one piece, it may be
divided into a cylinder head section ("fin section'l) facing
away from the cylinder and a cover plate section ("deck section").
The cover plate section is made thick enough to achieve adequate
strer)gth and to ensure overall, stable, uniform sealing to the
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cylinder barrel. The bosses for the cylinder head attachment
bolts also terminate at the cover plate section, so that
the cylinder head section thereabove, racing away from the
cylinder, is defined by the gas-exchange ducts, the cooling
ribs, and a central area. The plane passing through -the valve
stems lies preferably at an acute angle of 30 in relation
to the longitudinal axis of the internal combustion engine.
Since the inlet duct, curved in the form of a hook, extends
from the valve to the centre of the cylinder head, and the
exhaust duct runs by the shortest path thereto, substantially
at right angles Jo -the exhaust air side, such produces an
arcuate or S-shaped cooling air duct - when two assembled
cylinder heads are viewed from above. Within this created
cooling air duct, the cooling air is repeatedly deflected, thus
achieving very good heat transfer. Furthermore, this cooling duct,
which, depending upon the size of the cooling ribs, may be
divided into a plurality of arcuate or S-shaped sections, is
very large since it is not obstructed by the bosses for the
attachment bolts. According to some embodiments in accordance
with the invention, there is provided a flow of cooling air
in the vicinity of the exhaust valve or exhaust duct in the
cover plate section also, said flow comprising a partial flow
of air arriving linearly and a partial flow of air passing
over ribs obliquely arranged namely ones positioned at an
acute angle to -the cylinder axis, in the cover pla-te sectionO
The partial flow of air passing over the obliquely arranged
ribs is branched off the main flow of air,
By arranging additional V-shaped ribs and parallel
ribs in the cover plate section on the exhaust air side,
according to a further embodiment, and by arranging fairings
on the exhaust air side, according to a still further embodi-
ment, parts of the arcuate or S-shaped main cooling air flow
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are also guided on the exhaust air side, in the area below
the exhaust duct, to the cover plate section. To this end,
the external contour of the cylinder head section facing away
from the cylinder is also recessed in relation to the cooling
ribs below the exhaust duct, thus allowing an adequately
large flow of air to reach these ribs. This is also assisted
by the extension and bending of the fairings along the upper
edges of the cylinder heads, according to a further embodiment,
and by the configurations shown in the drawings. Bending
the fairings on the exhaust air side and selecting suitable
flow though spacing to the exhaust duct contour, to the next
fairing, and to the edges ox the cylinder heads facing the
cylinders, ensures that the cooling air is accurately guided
and metered until it leaves the cylinder heads. To this end,
the fairings also comprise recesses in the area of the cover
plate section between two cylinder heads. The air guided
between the cover plate sections can thus emerge th Lo ugh
these recesses.
Tests have shown that the central area between the
gas exchange ducts may be made integral with the cylinder head,
i.e., solid and without interruption, and that the injection
nozzle located in this area is adequately cooled. Due to the
satisfactory cooling provided, no fur-ther cooling is necessary.
If, contrary to expectations, this central area should need
additional cooling, it is quite possible to provide cooling
ribs or coolant ducts. If desired, it is possible to provide
a recess between the exhaust duct and the central area, or
between the central area and the inlet duct.
Since the main cooling air duct between the cylinder
heads is arcuate or S-shaped, it is offered, according to one
embodiment, that the lateral deflectors shawl have expansions
corresponding to the guidance through each additional cylinder
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head. They are also advantageously connected, in one piece,
with the correspondi.ng part of the fairing.
In one aspect of the present invention there is
provided in an air cooled, reciprocating piston, internal
Gombustion engine having at least one row of cylinders
comprising individual cylinder heads arranged side-by-side,
the cylinder heads being provided with cooling ribs extending
substantially normal to the axes of the cylinders, the
cylinder heads including means for accommodating attachment
bolts, the cylinder heads each having at least one inlet valve
and one exhaust valve, the valve stems of which extend sub-
stantially parallel to the axes of the cylinders and
situated such that the plane passing through said valve stems
lies at an acute angle to the longitudinal axis of the internal
combustion engine, the cylinder heads each in.cluding an intake
duct located on a side thereof swept by cooling air, the
intake duct 'naving its opening located approximately centrally
of the cylinder head, the cylinder heads each including an
exhaust duct extending substantially perpendicularly to the
exhaust air side, and a lateral deflector being provided
adjacent the end cylinder head in each row, the improvement
comprising with the aid of external contours of the ducts,
in conjunction with central areas arranged between the
respective valve stems and the cooling ribs, the adjacently
arranged cylinder heads from one or more arcuate or S-shaped
cooling air ducts in a section of the cylinder head facing
away from the individual cylinder, and in that an enclosed
cover plate section facing the cylind~ of the individual
cylinder head is provided with cooling ribs at the cylinder
head periphery, substantially on the exhaust air side thereof,
and the side thereof facing the inlet valve stem, and com-
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comprises boss means for accommodating attachment bolts.
In a further aspect of the present invention
there is provided in an air cooled, reciprocating piston,
internal combustion engine having at least one row of cylinders
comprising individual cylinder heads arranged side-by-side
the cylinder heads being provided with cooling ribs extending
substantially normal to the axes of the cylinders, the cyl.inder
heads including means for accommodating attachment bolts,
the cylinder heads each having at least one inlet valve and
one exhaust valve, the valve stems of which extend substantially
parallel to the axes of the cylinders and sltuated such that
the plane passing through the valve stems lies at an acute
angle to the longitudinal axis of the internal combustion
engine, the cylinder heads each including an intake duct
located on a side thereof swept by cooling air, the intake duct
having its opening located approximately centrally of the
cylinder head, the cylinder heads each including an exhaust
duct extending substantially perpendicularly to the exhaust
air side, and a lateral deflector being provided adjacent the
end cylinder head in each row, the improvement wherein each of
the cylinder heads includes a central area between the valve
stems therein and wherein each cylinder head, due to the con-
tour thereof and housing the inlet and exhaust ducts and the
cooling ribs, provides at least one arcuate or S-shaped
cooling air duct between it and a similarly structured
adjacent cylinder head and wherein each cylinder head includes
a closed cover plate section facing the associated cylinder of
the individual cylinder head, each closed cover plate section
being provided with cooling ribs at the cylinder head periphery,
substan-tially on the exhaust air side thereof, and the side
thereof facing the inlet valve stem, and comprises boss means
for accommodating attachment bolts.
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In a further aspect of the present invention there
is provided in an air cooled, reciprocatiny piston, internal
combustion engine having at least one row of cylinders
comprising individual cylinder heads arranged side-by-side,
the cylinder heads being provided with cooling ribs, the
cylinder heads each having at least one inlet and one exhaust
valve and also having an intake duct and an exhaust duct
connected by a head area, the improvement comprising: in
respect of each head, contouring walls of the intake and
exhaust ducts and contouring the head area intermediate and
connecting the duct walls whereby to provide, between the
adjacently arranged cylinder heads, an arcuate cooling air
duct.
In a still further aspect of the present i.nvention
there is provided in an air-cooled, reciprocating piston,
internal combustion engine which defines a longitudinal axis
and which includes at least one row of cylinders comprising
individual cylinder heads arranged side-by-side, the cylinder
heads being provided with cooling ribs extending substantially
normal to the axes of the cylinders, the cylinder heads
including means for accommodating attachment bolts, the
cylinder heads each having at least one inlet valve and one
exhaust valve, the valve stems of which extend substantially
parallel to the axes of the cylinders and are situated such
that the plane passing through the valve stems lies at an
acute angle to the longitudinal axis of the internal combustion
engine, the cylinder heads each including an intake duct
located on a side thereof which is swept by cooling air, the
intake duct having its inlet opening aligned approximately
centrall.y of the cylinder head, the cylinder heads each
including an exhaust duct extendi.ng substantially perpendicularly
to the exhaust air side, and a lateral deflector being provided
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adjacent the end cylinder head in each row, the improvement
wherein each of the cylinder heads includes a central area
between the valve stems therein, and wherein each cylinder head
is externally shaped to provide at least one arcuate or S-shaped
cooling air duc-t between it and an adjacent, similarly con-
structed cylinder head, and wherein each cylinder head includes
an enclosed cover plate section facing the associated cylinder
of the cylinder head, the enclosed cover plate being provided
with cooling ribs at the cylinder head periphery, substantially
on the exhaust air side thereof, and the side thereof facing the
inlet valve stern, and includes boss means for accommodating
attachment bolts.
The invention is illustrated by way of example
in the accompanying drawings wherein:
Figure 1 is a side elevational view of an air cooled
cylinder head in accordance with the present invention;
Figure 2 is a view in the direction of the exhaust
air side of the head, showing the exhaust duct flange of the
cylinder head shown in Figure 1,
Figure 3 is a cross sectional view through the
lateral deflectors and fairings on the exhaust air side, and
through the cylinder heads, along the line III-III in Figure
5, with arrows indicating the flows of cooling and exhaust
air;
Figure 4 is a side elevational view of the cylinder
head shown in Figure 1, with a cross section through a mounted
fairing on the exhaust air side and arrows showing the flows
of cooling and exhaust air, and
Figure 5 is a view of a plurality of cylinder heads
similar to that shown in Figure 2, with fairings on the
exhaust air side mounted and removed.
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In Figures 1 to 5, 1 denotes a single cylinder head
of an air cooled reciprocating internal combustion engine, the
exterior of which is substantially cube-shaped and comprising
an inlet duct 2 and an exhaust duct 3 arranged on opposite
sides of the said cylinder head. The said inlet and exhaust
ducts comprise valves, (not shown), which define ducts at the
ends facing the cylinder, (not shown). The cylinder heads
when mounted are swept by cooling air, indicated in Figures
1, 3 and 4, which arrives at the inlet end of the inlet duct
and leaves the cylinder heads on the exhaust duct side.
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As shown more particularly in Figure 3, the plane
passing through -the stems, (not shown) of the valves, lies
at an acu-te angle of 30 in relation to the longitudinal
axis of the internal combustion engine. Inlet-duct 2 opens
at the centre of the cylinder head and extends, merging in-to
a swirl-shaped duct, to the outside of the cylinder head.
Exhaust duct 3 ex-tends, by the shortest path, outwardly and
therefore opens, offset in relation to the centre of the cylinder
head, at right angles to the exhaust air side of cylinder head
1. As also shown, in Figure 3, a central area 4 is provided
between inlet duct 2 and exhaust duct 3, the central area
being, in this example of embodiment of the invention, solid
and integral with the cylinder head. The configuration of
the cylinder head produces, in conjunction with an adjacently
arranged cylinder head, an arcuate or S-shaped cooling air duct
5 in whieh the cooling air i.s repeatedly defleeted and is
therefore utilized to optimal effect. As may be gathered more
partuclarly from Figures 1 and 2, the cylinder head eomprises
a eover plate seetion or deck seetion~6 which upon assembly
faces a cylinder, (not shown) and is of substantially solid
design having little ribbing, and a cylinder head section or
fin section 7. The latter comprises cooling ribs 8 arranged
substantially perpendicularly to the axis of the eylinder
and extending from duets 2, 3 and central area 4, to the cube-
shaped external contour of the cylinder heads. Cover plate
seetion 6 has, at its corners, bosses for accommodating attach-
ment bolts shown in Figure 5. As shown more particularly in
Figures 1 and 4, the cover plate seetion comprises, obliquely
arranged ribs 8a extending at an acute angle to the axis of the
cylinder. Arranged between ribs 8a and the cylinder, (not
shown), is a channel 10 having ribs 8b. A seen in Figures 1
and 4, channel 10 is expanded in the vicinity of the oblique
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ribs and the channel ribs, so that the combined partial flows
of air can flow away from the heads, as shown in Figure 4.
Depending upon the desired magnitude of the flows of cooling
air through -the lateral ribs on the cover plate section, the
adjacent cylinder head may comprise a suitable recess on the
adjacen-t side thereof.
As seen in Figure 2, cover plate section 6 comprises
ribs 8c on the exhaust air side extending V-shaped, at an
acute angle to the axis of the cylinder, beneath exhaust duct
3. Almost adjoining ribs i3c are ribs 3d extending parallel
with the axes of the cylinders.
As also shown in Figures 3 and 4, incoming cold
air (indicated by outlined arrows) is divided into a main
air flow, flowing through the arcuate or S-shaped cooling
air duct, and a partial air flow flowing laterally through
the cover plate section. The cold air is heated by the walls
of the cylinder head and passes out as hot air (solid arrows).
Arranged on the exhaust air side, between each two cylinder
heads is a fairing 11 which, as shown in Figure 5, comprises,
laterally and at the edges of the cylinder heads facing the
cylinders, a flow through spacing whereby the volume of
cooling air is throttled or choked for the purpose of ensuring
satisfactory cooling of the cylinder head, and is also caused
to flow completely around the exhaust air side. Between the
-two cylinder heads, seen in E'igure 5, fairing 11 has a
recess 13 through which the flow of cooling air arriving from
the lateral ribs on cover pla-te section 6 may emerge. In the
vicinity of -the upper edges of the cylinder heads, fairing 11
is bent round at right angles and follows the upper contour
of the cylinder heads, best seen in Figure 4. This provides
an upper limit to the arcuate or S-shaped cooling airduct-to the
ribs on the exhaust air side of the cover plate section 6,
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below exhaust auct 3.
Deflectors 14 are provided for lateral guidance
of the flows of cooling air at the encl of each row of
cylinders, the deflectors being shaped in such a manner that
they replace the external contour of an aajacently arranged
cylinder head and a part of the corresponding fairing, thus
maintaining the arcua-te or S-shaped cooling air duct.
This latter configuration of the cylinder heads
produces overall highly satisfactory guidance of the flow of
cooling air and excellent utilization thereof. Such makes
it possible for the central area of the cylinder head to be
solid An injection nozzle for a self igniting Diesel engine
may thus be arranged in a bore 15 in the central area which is
an optimal location from the point of view of combustion
technology, and assures the nozzle does not become overheated.
