Note: Descriptions are shown in the official language in which they were submitted.
10996~i3
The invention relates to a multi-cylinder, in-line,
reciprocating-piston, internal combustion engine having a crank-
shaft with a Z-shaped crankpin upon which a universal joint having
a hollow shaft is rotatably mounted.
A reciprocating-piston internal combustion engine of
this kind is known (see "Der Motorwagen" 1927, page 692, Fig. 15).
In this known engine, a rocker with two pistons is associated with
each crankpin laterally of the crankshaft. Although the engine
obtained with this complex mechanism is lower than conventional
engines, it is also wider. Moreover, the inertial forces produced
by the pistons, connecting-rods and rockers, which counteract the
gas forces, are absorbed by the universal joint in the housing,
and are transferred by the universal joint to the crankshaft. As
a result, the load is applied to all of the crankshaft bearings.
The present invention proposes to provide a compact
reciprocating-piston internal combustion engine, using proven
components of conventional piston engines, in which the crank-
shaft is required to absorb only the effective and alternating
torque of the engine and minor centrifugal forces produced by
the crosshead of the hollow shaft.
According to the invention, this is achieved, in the
case of a multi-cylinder, in-line, reciprocating-piston, internal
combustion engine having a crankshaft with a Z-shaped crank-
pin upon which a universal joint having a hollow shaft is rota-
tably mounted. The universal joint has journals arranged dia-
metrically at right angles to the axis of rotation, to which
journals the other part of the joint is articulated, this part
being mounted in the housing at right angles to the journals and
being connected to, and secured against rotation in relation to,
a double rocker to which pistons are hinged by means of connect-
ing rods. The part of the universal joint mounted in the housing
surrounds the journal in the form of a box or dish, and is
mo~nted diametrically of the crankshaft, each journal comprising
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diametrically arranged double rockers having two pistons each.
In accordance with one aspect of the present inven-
ti~n, there is provided a multi-cylinder reciprocating-piston
int:ernal combustion engine having parallel rows of in-line
cylinders, comprising a casing containing a crankshaft with a
Z-~haped crank, one part of a universal coupling with a hollow
shaft carried on the crank, the said one part having bearing
pins which are disposed diametrically in relation to the
axis of rotation of the crankshaft, the other part of the
universal coupling being mounted on the bearing pins and
supported in bearings in the casing, the said other part
being connected to two double-ended rocking levers, and
pistons carried on connecting rods connected to the ends of
the rocXing levers, in which the said other part of the
uni~ersal coupling surrounds the crank in the manner of a
box or ~hell, and is mounted diametrically in relation to
the crankshaft.
In it~ simplest form, that of a four-cylinder design,
the configuration according to the present invention produces
an almost cube-~haped engine in which optimal use is made of the
space, with respect to width, length and height. Ignition
intervals are equally spaced. Furthermore, the rocker may be
designed quite simply in rigid relationship to the dish-shaped
portion of the universal joint. Forces producing no effective
torque at the crankshaft are absorbed directly by the diametri-
cally arranged bearings in the housing. These forces are easily
supported by radial bearings of conventional design. The
crankshaft itself transfers only effective torque, has greater
torsional rigidity due to its short length, and may therefore
be smaller. Another advantage is that only radial forces act
at all bearing locations, and these are easier to ~upport than
axial forces.
According to one embodiment of the invention, the
universal-joint bearings in the housing are adjustable in the
direction of movement of the pistons. Moreover, the universal
joint has 80 much axial play in its bearings that the axial
movements arising when the bearings in the housing are adjusted
lie within the predetermined play.
Adjusting the bearing locations makes it possible to
alter the compression ratio, since the dead areas in the opera-
ting cylinders are thus enlarged or reduced. Since-the bearing
locations in the housing are easily accessible, it is not very
difficult to provide means of adjusting them. Internal bear-
ings, such as the mountings of the hollow shaft upon the jour-
nal, are not affected, since they automatically adapt to the
changed operating conditions by virtue of their axial play.
Deviationq from the theoretically ideal position, in which the
axes of the universal joint, arranged at right angles to each
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other, and the axis of the crankshaft intersect at a point, are
compensated for by an axial rocking movement in the universal-
joint bearing locations, e.g. of the hollow shaft on the crank-
pin, the magnitude of the axial rocking movements being depend-
~nt upon the magnitude of the deviation. In the case of an
effective change in compression ratio, these axial rocking move-
ments are of a structurally acceptable order of magnitude, so
that there is no difficulty in providing adequate axial bearing
play. Movements brought about by production tolerances are also
absorbed by the axial play.
It is often desirable to alter the compression ratio
in order that engine performance may be better adapted to require
ments. For instance, it is possible to operate heavily loaded
internal combustion engines which, at full load, have equal peak
pressures and engine loads over the whole load-range, and which
achieve good starting performance if the compression ratio is
raised during the start and run-up phase. If the starting per-
formance is to be improved, it should be possible to run the
engine up to an optimal starting r.p.m. at a very low compression
ratio, and then to change over to the higher starting ratio.
This has the effect of a decompression unit.
In a further embodiment of the invention, it is pro-
posed that the crankshaft and/or the universal joint enter partly
into lateral recesses in the rocker when the piston is at half-
stroke. This makes it possible to reduce the width of the engine.
Moreover, there are short distances between the points of attack
of the forces and the bearing ~ocations, so that the torque to
be transferred by the components can be kept low.
According to another embodiment of the invention, and
for the purpose of simplifying the adjustment of the compression
ratio, it is proposed to mount the universal joint in the housing
in two eccentric sleeves rotating in opposite directions. If
1~996~3
the bearing in the inner eccentric sleeve is secured to the
housing so that it does not rotate therein, then, when the
engine is under load, the same torque is produced in both
eccentrics, each torque cancelling the other out in counter-
rotation. With the retaining forces thus eliminated, only
frictional torque has to be overcome in the adjusting mechan-
ism in making any desired adjustment. Another way of effecting
this adjustment is to adjust the housing bearings of the univer-
sal joint by means of a cam which can be locked in position.
Still another embodiment of the invention discloses
hydraulic or pneumatic means of adjustment, in which case the
housing bearings of the universal joint are adjusted by spring-
loaded pistons actuated hydraulically or pneumatically. These
sprlngs may also be arranged in such a manner that, in addition
to returning the pistons, they serve to limit the m~ximal ig-
nition pressure, in which case the springs are preferably adjust-
abb. It is, of course, also possible to make use of other
adjusting or control means, for instance mechanically, hydraul-
ically or electrically-actuated levers or articulating systems,
slides having cams or ke~ways, spiral gearing, or direct-acting
cylinders, as long as they permit synchronized adjustment of co-
operating bearing locations.
According to another embodiment of the invention, the
housing bearings may be adjusted by a control device and adjust-
ing elements, whereby the bearings are adjusted as a function of
critical engine operating parameters, e. g. a critical component
temperature, exhaust-gas temperature, ignition pressure, r.p.m.,
load, suction pressure, intake pressure, etc.
The internal combustion engine according to the in-
vention has inertial forces produced by the pistons, connecting-
rods and rockers, and the~e forces, combined by the rockers,
jointly counteract the gas forces, so that the load on the uni-
versal joint is only that produced by the effective and alternat-
-- 4 --
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ing torque. According to the invention, all of the inertial
forces are preferably compensated for by two counterweights on
the crankshaft co-operating with two compensating weights rotating
in opposite directions, thus eliminating any free inertial
forces. E~uivalent to the rotating counterweights are swinging
weights arranged on or in the internal combustion engine.
In drawings which illustrate embodiments of the
present invention:
Figure 1 is a partial, vertical, longitudinal
section through a row of cylinders of an internal
combustion engine according to the present invention;
Figure 2 is a cross-section through two opposing
rows of cylinders of an internal combustion engine
according to the present invention'
Figure 3 is a horizontal longitudinal section on
a level with the crankshaft axis:
Figure 4 is a vertical longitudinal section through
the crankshaft axis:
Figure 5 is a diagrammatic representation of an
arrangement of counterweights and compensating weights
and of a pressure-actuated adjusting device, and
Figure 6 is a design similar to that of in Figure
5, but with an adjusting device in the form of a cam.
As seen in Figures 1 to 4, arranged in an engine housing
1 are cylinders 2 in which pistons 3 are axially displaceable.
The ends of cylinders 2 are closed off by cylinder heads 4 con-
taining conventional gas-exchange ducts and control elements,
not shown in detail in the drawings. The bottom of the engine
is closed off by means of a lubricating-oil sump 5.
The pistons 3 are connected by means of gudgeon-pins
6 and connecting-rods 7 to a double rocker 19 made integral
with outer part 8 of a universal joint, The outer part 8 is
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1099603
,,
pivotably mounted in housing 1 in adjustable bearings 9.
The bearings 9 are in the form of two eccentric sleeves 10, 11
adapted to rotate in opposite directions. Cranks 12 are linked
to the ends o~ the sleeves 10, 11 and are used for synchronous
adjustment of the sleeves. The cranks 12 are actuated by means
of a hand-crank 13 mounted on the housing 1. The hand-crank
13 may, of course, be replaced by adjusting elements of an
automatic control device. Synchronous rotation of eccentric
sleeves 9, 10 adjusts bearings 9 in the direction of movement
of pistons 3.
Mounted in outer part 8 of the universal joint by
means of journals 15 is inner part 14 thereof, the axes of the
journals 15 being at right angles to the axes of bearings 9. Inner
part 14 of the universal joint also has a hollow shaft 16 running
at right angles to the axis of journals 15, the shaft 16 being
mounted upon a Z-shaped crankpin 17 of a crankshaft 18 mounted
in housing 1. The hollow shaft 16 has so much axial play that,
when bearings 9 are adjusted in the direction of travel of pis-
tons 3, it can move freely upon crankpin 17 within the adjustment
travel, without impinging upon cheeks 20 of crankshaft 18.
As may be gathered from Figure 2, outer part 8 of the
universal joint, which is connected to double rockers 19, surrounds
crankpin 17 in the manner of a box, the outer part 8 being a very
strong and rigid component which can therefore absorb large for-
ces. Double rockers 19 have lateral recesses 21 into which uni-
versal joint 8 enters when piston 3 is at half-stroke. Recesses
21 make it possible to locate the rows of cylinders and the
force-attack-points as close as possible to each other, thus
producing a light and compact structure.
Instead of adjusting bearings 9 by means of eccentric
sleeves 10, 11, it is also possible, as seen in Figure 5, to use
hydraulically or pneumatically actuated pistons 22 having piston-
10996 013
rods 23 engaging bearings 9 and running axially in cylinders 24.
The piston crowns are spring-loaded, springs 25 adjusting bear-
ings 9 in the direction of maximum compression ratio. With no
assistance from any pressure medium, springs 25 also serve to
limit the ignition pressure, the maximum ignition pressure being
predetermined by the stiffness of the springs 25. In this case,
it is desirable to dampen the movement of piston 22, for instance,
by means of a choke. If a pressure medium is used to actuate
piston 22, it is possible to establish a fixed compression
ratio which can be optimally adapted to operating conditions.
As seen in Figures 6, bearings 9 may also be adjusted
by means of a tappet 26 and a cam which can be locked in posi-
tion.
In Figure 5, inertial forces are equalized by counter-
weights 28 arranged upon the crankshaft and co-operating with
counter-rotating compensating weights 29. Weights 29 are
secured to a shaft 30 which is mounted in housing 1 between the
rows of cylinders and is driven from crankshaft 18 by gears 31,
32 in the opposite direction of rotation. Also secured to one
end of the crankshaft 18 is a flywheel 33.
