Note: Descriptions are shown in the official language in which they were submitted.
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ENGINE WITH CRANKCASE COMPRESSION
RELATED APPLICATIONS
This application is based on U.S. Provisional Application
No. 60/101,298, entitled "Engine with Crankcase
Precompression," filed on September 22, 1998.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to an engine in which fluid for
generating power is compressed.
pescription of the Prior Art
Internal combustion engines represent one class of engines
which generate power from compressed fluid. In such
engines of the Otto cycle type, a piston reciprocating in
a cylinder produces a vacuum during part of each operating
cycle. The vacuum causes a volume of air, or air and
fuel, approximately equal to the displacement of the
piston to be sucked into the cylinder. This volume of
air, or air and fuel, is then compressed by the piston
inside the cylinder and subsequently ignited. The
combustion products obtained upon ignition expand and
cause displacement of the piston. The piston, in turn,
through a connecting rod, rotates a crankshaft or drive
member which serves as a power source.
Much effort has been expended in increasing the power
output of internal combustion engines. This is generally
accomplished with a supercharger which forces additional
air into a cylinder by means of a fan or positive
displacement rotors.
While a supercharger is effective in increasing power
output, the supercharger adds substantially to the
complexity, weight and cost of the engine. Furthermore, a
supercharger greatly increases the probability of
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detonation and pre-ignition which can destroy an engine in
a short time. For this reason, supercharged engines
frequently have lower reliability ratings than normally-
aspirated engines.
The crankshaft of the engine, which is located in a
crankcase, has journals or carrying elements supported by
bearing sleeves or shells. A lubrication system is
provided for the engine, and a major duty of the
lubrication system is to remove heat from the journals and
bearing sleeves. This poses little problem in smaller
engines where the journals and bearing sleeves are small
and the distance from the hottest location of a journal or
bearing sleeve to the relatively cool atmosphere of the
crankcase is not great. However, in larger engines where
the journals and bearing sleeves are relatively large, the
lubrication system may be unable to remove sufficient
heat from the journals and bearing sleeves.
Although adequate cooling in larger engines can be
achieved by replacing the bearing sleeves with roller
bearings or ball bearings which are more easily cooled,
weight, noise and cost would all increase.
SUMMARY OF THE INVENTION
It is an object of the invention to increase the power
output of an engine relatively simply.
Another object of the invention is to reduce the
likelihood of detonation in an engine.
An additional object of the invention is to enhance the
cooling of the carrying and bearing elements for a drive
member of an engine with little or no increase in weight,
noise or cost.
The preceding object, as well as others which will become
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apparent as the description proceeds, are achieved by the
invention.
One aspect of the invention resides in an engine which
comprises wall means defining a first passage, a secand
passage, and a compartment arranged to open to each of the
passages. The first passage has one first end facing the
compartment and an opposite first end remote from the
compartment. Similarly, the second passage has one second
end facing the compartment and an opposite second end
remote from the compartment. A first member is
reciprocable in the first passage and a second member is
reciprocable in the second passage. The engine further
comprises means for admitting fluid into the compartment
and means for transferring fluid from the compartment to
the remote first end and the remote second end. The
engine also comprises fluid flow control means arranged to
establish communication between the transferring means and
the remote first end while sealing the remote second end
from the transferring means. The fluid flow control means
is further arranged to establish communication between the
transferring means and the remote second end while sealing
the remote first end from the transferring means. The
engine additionally comprises drive means driven by the
reciprocable members. The drive means and reciprocable
members are arranged such that the first and second
reciprocable members concurrently move towards those ends
of the respective first and second passages which face the
compartment. The drive means and reciprocable members are
likewise arranged so that the first and second
reciprocable members concurrently move towards the remote
first end and the remote second end, respectively.
In the above engine, the reciprocable members move away
from a compartment at the same time. This allaws a
quantity of fluid equal to the sum of the displacements of
the reciprocable members to be drawn into the compartment.
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The reciprocable members subsequently move towards the
compartment at the same time thereby enabling the fluid to
be compressed. The fluid flow control means is preferably
arranged so that, when the reciprocable members move
towards the compartment, communication is established
between the compartment and one of the two passages in
which the reciprocable members ride. Consequently, the
fluid is forced into this passage by the reciprocable
members and the passage receives a volume of fluid
significantly greater than the displacement of the
respective reciprocable member. When the reciprocable
members now move away from the compartment, the fluid
previously fed into the one passage can undergo additional
compression. In this manner, a supercharging effect may
be obtained.
The above engine permits a supercharging effect to be
achieved without complex fan or rotor mechanisms.
Moreover, this supercharging effect is essentially free
since it makes use of the normal motions of reciprocable
members in engines.
Another aspect of the invention resides in an engine which
comprises wall means defining at least one passage as well
as a compartment arranged to open to the passage. The
passage has one end facing the compartment and another end
remote from the compartment. A reciprocable member is
reciprocable in the passage, and a drive member in the
compartment is arranged to be driven by the reciprocable
member. The engine further comprises means for admitting
fluid into the remote end of the passage, and fluid flow
control means for regulating the admission of fluid into
such end. The fluid flow control means includes a
rotatable valve member, and the valve member is provided
with at least one port which is arranged to receive fluid
from the admitting means and to admit fluid into the
remote end of the passage. The valve member has an axis
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of rotation and is shiftable along this axis.
The engine can be provided with a port, e.g., in a head of
the engine, which overlaps the port in the valve member
5 when fluid is to be admitted into the passage containing
the reciprocable member. In this condition the port in
the valve member is open while the same port is closed
when there is no overlap with the port in the head.
By designing the valve member to be rotatabie as well as
shiftable axially, it becomes possible to accomplish more
than simply opening and closing the port in the valve
member. Thus, one of the motions can be used for this
purpose while the other mation can be used to vary the
amount of overlap of the port in the valve member and the
port in the head. A change in the amount of overlap, in
turn, permits the turbulence of the fluid to be increased
or decreased. An increase in turbulence when the engine
is operating under conditions favoring detonation allows
the probability of this phenomenon to be reduced.
An additional aspect of the invention resides in an engine
which, as before, comprises wall means defining at least
one passage as well as a compartment arranged to open to
the passage. A reciprocable member is again reciprocable
in the passage, and a drive member in the compartment is
again arranged to be driven by the reciprocable member.
In this aspect of the invention, the engine further
comprises a bearing element for the drive means, and the
bearing element is provided with at least one cooling
channel which extends along a sectin of the drive means
and is open to the drive means along such section.
In this engine, a cooling channel in a bearing element is
adjacent a drive means, e.g., a crank, supported by the
bearing element. The cooling channel is thus at the
hottest location of the bearing element and allows the
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bearing element to be efficiently cooled at this location.
Moreover, cooling fluid flowing through the cooling
channel can cool the adjoining section of the drive means
simultaneously with the bearing element. The cooling
channel allows cooling of the bearing element to be
improved with little, if any, increase in the weight and
cost of the engine or the noise generated by the engine.
Yet another aspect of the invention resides in a method of
l0 operating an engine which comprises the step of drawing
fluid into a compartment by concurrently moving each of
two reciprocable members along a respective passage from a
first position nearer the compartment to a second position
farther away from the compartment. The method further
comprises the step of compressing the fluid and
introducing at least a portion thereof into one of the two
passages by concurrently moving each of the reciprocable
members in a direction from the respective second position
towards the respective first position. The method also
comprises the step of additionally compressing the portion
of the fluid introduced into the one passage within such
passage by moving the respective reciprocable member in a
direction from the respective first position towards the
respective second position. The reciprocable members
preferably move in diametrically opposite directions.
The method can further comprise the step of rotating a
valve member to control the flow of the abovementioned
portion of the fluid. The method may also include the
step of driving a drive member with the reciprocable
members, and the drive member can, in turn, rotate the
valve member.
One more aspect of the invention resides in a method of
operating an engine which comprises the steps of admitting
fluid into a passage, and compressing the fluid in the
passage by moving a reciprocable member along the passage
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in a predetermined direction. This method additionally
comprises the steps of moving the reciprocable member
along the passage in a direction opposite to the
predetermined direction following the compressing step,
and controlling the flow of fluid into the passage. The
controlling step includes rotating a valve member on an
axis of rotation, arid shifting the valve member along the
axis.
A further aspect of the invention resides in a method of
operating an engine which comprises the steps of
reciprocating a reciprocable member, and driving a drive
member with the reciprocable member. The drive member has
a carrying element which is received by a bearing element,
and the method also comprises the step of cooling the
bearing element. The cooling step includes establishing
fluid flow between the carrying element and the bearing
element.
The method according to this aspect of the invention can
further comprise the step of admitting fluid into the
carrying element from a location between the bearing
element and the carrying element.
Additional features and advantages of the invention will
be forthcoming from the following detailed description of
preferred embodiments when read in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of an engine in accordance
with the invention.
FIGS. 2a-2g are somewhat schematic and simplified partly
sectional elevational views of the engine of FIG. 1
showing different operating stages of the engine.
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FIG. 3 is a partly sectional elevational view of a valve
member forming part of the engine of FIG. 1.
FIG. 4 is a fragmentary elevational view of a crankshaft
and connecting rods forming part of the engine of FIG. 1.
FIG. 5 is a fragmentary elevational view of the crankshaft
of FIG. 4 illustrating additional details of the
crankshaft.
l0
FIG. 6 is a fragmentary view showing the inner surface of
a bearing for the crankshaft of FIG. 4.
FIG. 7 is a fragmentary view showing the inner surface of
a further bearing for the crankshaft of FIG. 4.
FIG. 8 is a fragmentary view showing the inner surface of
an additional bearing for the crankshaft of FIG. 4.
FIG. 9 is similar to FIG. 5 but illustrates another
embodiment of the crankshaft.
FIG. l0 is a simplified fragmentary sectional view of the
engine of FIG. 1 taken in a horizontal plane and showing
one more bearing for the crankshaft of FIG. 4.
FIG. 11 is a fragmentary partly sectional view of an
engine similar to that of FIG. 1 taken in a vertical plane
and illustrating a cylinder head and valve of the engine.
FIG. 12 is a bottom view of the cylinder head of FIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 and FIGS. 2a-2g, the numeral 10
identifies an engine according to the invention. The
engine 10 is here an internal combustion engine but could
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be another type of engine which generates power using
compressed fluid.
The engine l0 comprises a casing or housing 12 which
includes a cylinder block, a cylinder head and a crankcase
and contains two identical cylinders. The engine casing
12 has a plurality of walls, including a front wall 14, a
back wall 16, a top wall 18 and a bottom wall 20, which
cooperate to define a crankcase chamber or compartment 22
and a pair of cylinder bores or passages 24 and 26. The
crankcase chamber 22 runs between the cylinder bores 24,26
which extend away from the crankcase chamber 22 in radial
direction thereof. The cylinder bores 24,26, which have a
circular cross section, are located on opposite sides of
the crankcase chamber 22 and run in diametrically opposite
directions.
The cylinder bore 24 has a longitudinal end 24a adjacent
to and facing the crankcase chamber 22 and an opposite
longitudinal end 24b remote from the crankcase chamber 22.
Likewise, the cylinder bore 26 has a longitudinal end 26a
adjacent to and facing the crankcase chamber 22 and an
opposite longitudinal end 26b remote from the crankcase
chamber 22. Each of the longitudinal ends 24a,26a opens
to the crankcase chamber 22 which is in permanent
communication with the two cylinder bores 24,26 through
such longitudinal ends 24a,26a.
The longitudinal bore end 24b remote from the crankcase
chamber 22 is regulated by a valve mechanism or flow
control mechanism 28. Similarly, the longitudinal bore
end 26b remote from the crankcase chamber 22 is regulated
by a valve mechanism or flow control mechanism 30. The
valve mechanism 28 is mounted in a cylinder head 106
having a flange 106a which is attached to a non-
illustrated exhaust pipe by bolts 108. In like manner,
the valve mechanism 30 is mounted in a cylinder head 110
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having a flange 110a which is attached to a non-
illustrated exhaust pipe by bolts 112 .
Preferably, each of the valve mechanisms 28,30 comprises a
5 rotatable valve member or flow control member 32 shown in
FIG. 3.
Considering FIG. 3, the valve member 32 includes an
elongated valve element 34 of circular cross section
10 having a tubular intake section 36 and a tubular exhaust
section 38. Both the intake section 36 and the exhaust
section 38 run longitudinally of the elongated element 34,
and the intake section 36 and exhaust section 38 are
separated from one another by a partition or dividing wall
40 extending across the lumen of the elongated element 34.
The intake section 36 has a longitudinal end 36a remote
from the partition 40, and a series of receiving ports or
openings 42 is provided in the longitudinal end 36a. The
receiving ports 42, which serve to introduce fluid into
the interior of the intake section 36, form an interrupted
ring which runs circumferentially of the intake section
36. The intake section 36 is further provided with a
series of discharge ports or openings 44 between the
receiving ports 42 and the partition 40. The discharge
ports 44, which serve to transfer fluid from the intake
section 36 to the cylinder bore 24 or 26, are arranged in
a row extending longitudinally of the intake section 36.
The ports 42,44 constitute the only parts or openings in
the intake section 36.
The exhaust section 38 has a longitudinal end 38a remote
from the partition 40, and a series of inlet ports or
openings 46 is provided in the exhaust section 38 between
the partition 40 and the longitudinal end 38a. The inlet
ports 46, which serve to transfer fluid from the cylinder
bore 24 or 26 to the interior of the exhaust section 38,
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are disposed in a row running longitudinally of the
exhaust section 38. The longitudinal end 38a is open to
permit the discharge of fluid from the exhaust section 38
into an exhaust system.
The discharge ports 44 of the intake section 36 and the
inlet ports 46 of the exhaust section 38 can be round,
square, triangular or trapezoidal but preferably have an
oval shape or an approximately oval shape. The discharge
ports 44 are offset :from the inlet ports 46
circumferentially of the elongated element 34, e.g., by
about 90 degrees.
The elongated valve element 34 has an additional section
48 which is fast with the longitudinal end 36a of the
intake section 36. The additional section 48 is provided
with an array of splines or grooves 50, and the splines 50
form a circle which runs circumferentially of the
additional section 48. The splines 50 are designed to
engage a drive sprocket or rotating element which
functions to rotate the valve member 32, and the
additional section 48 may accordingly be considered a
drive section of the elongated element 34.
In FIG. 3, the longitudinal end 36a and additional section
48 of the elongated 'valve element 34 have a larger outer
diameter than the remainder of the valve element 34.
The elongated valve element 34 can be one piece or an
assembly.
FIG. 1 shows a drive sprocket or rotating element 52 for
the valve member 32 of each valve mechanism 28,30. The
end of each drive section 48 remote from the respective
intake section 36 is provided with a non-illustrated
threaded hole arranged to receive a retaining bolt or
retaining element 54 for the associated valve drive
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sprocket 52.
Turning back to FIGS. 2a-2g, a piston or reciprocable
member 56 of circular cross section rides in the cylinder
bore 24. The piston 56 is movable between a position
adjacent to the crankcase chamber 22 (FIG. 2a) and a
position near but spaced from the valve mechanism 28 (FIG.
2b). These two positions can respectively be referred to
as bottom dead center and top dead center. The piston 56
is a close sliding f.it in the cylinder bore 24 and forms a
seal between the longitudinal ends 24a,24b of the bore 24.
The portion of the bore 24 on the side of the piston 56
remote from the crankcase chamber 22, together with the
combustion side of the cylinder head 106, constitutes a
combustion chamber. Combustion in the cylinder bore 24
can be initiated by a spark plug or ignition source 58.
In the case of compression-ignition as occurs, for
instance, in a diesel engine, combustion can be initiated
by the injection of atomized fuel.
A second piston or reciprocable member 60 of circular
cross section rides in the cylinder bore 26. The piston
60, which is identical to the piston 56, is displaceable
between a position adjacent to the crankcase chamber 22
(FIG. 2a) and a position near but spaced from the valve
mechanism 30 (FIG. 2b). As before, these two positions
can respectively be referred to as bottom dead center and
top dead center. The piston 60 is a close sliding fit in
the cylinder bore 26 and forms a seal between the
longitudinal ends 26a,26b of the bore 26. The portion of
the bore 26 on the side of the piston 60 remote from the
crankcase chamber 22, together with the combustion side of
the cylinder head 110, constitutes a combustion chamber.
An ignition source or spark plug 62 can be used to
initiate combustion in the cylinder bore 26. However, for
compression-ignition as occurs, for example, in a diesel
enging, combustion can be initiated by the injection of
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atomized fuel.
It is preferred for the engine 10 to have a highly
oversquare design, that is, a large bore-to-stroke ratio.
Considering FIG. 4 in conjunction with FIGS. 2a-2g, a
crankshaft or drive member 64 is located in the crankcase
chamber 22. The crankshaft 64 has an axis of rotation R
which is perpendicular to the axes of the cylinder bores
24,26. The crankshaft 64 is provided with a crank
arrangement 66 comprising two lateral cranks 68 and 70
which are spaced from one another axially of the
crankshaft 64. The crank arrangement 66 further comprises
a central crank 72 which is situated between the lateral
cranks 68,70.
The lateral crank 68 includes a spaced pair of crank arms
or webs 68a and 68b which carry a crankpin or journal
68c. Similarly, the lateral crank 70 includes a spaced
pair of crank arms or webs 70a and 70b which carry a
crankpin or journal 70c. The crank arm 68b of the lateral
crank 68 and the crank arm 70b of the lateral crank 70
also constitute respective crank arms of the central crank
72. Thus, the central crank 72 has the crank arm 68b in
common with the lateral crank 68 and the crank arm 70b in
common with the lateral crank 70. The crank arms 68b,70b
carry a crankpin or journal 72c of the central crank 72.
The crank arms 68a,68b,70a,70b can be circular and are
perpendicular to the rotational axis R of the crankshaft
64. The crank arms 68a,68b,70a,70b all have the same
thickness and diameter, and the diameter of the crank
arms 68a,68b,70a,70b constitutes the maximum diameter of
the crankshaft 64. The rotational axis R of the
crankshaft 64 passes through the centers of the crank arms
68a,68b,70a,70b.
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The crankpins 68c,70c,72c are also circular, and the axes
of the crankpins 68c,70c,72c are parallel to the
rotational axis R of the crankshaft 64. The lateral
crankpins 68c,70c have the same length, and this length is
one-half that of the central crankpin 72c as seen in FIGS.
2a-2g.
The lateral crankpins 68c,70c are coaxial and located to
one side of the rotational axis R of the crankshaft 64.
The central crankpin 72c is disposed on the diametrically
opposite side of the rotational axis R, and the crankpins
68c,70c,72c are equidistant from such axis R.
A lateral connecting rod or elongated connecting member 74
is attached to the lateral crankpin 68c while a lateral
connecting rod or elongated connecting member 76 is
attached to the lateral crankpin 70c. Likewise, a central
connecting rod or elongated connecting member 78 is
attached to the central crankpin 72c. The central
connecting rod 78 is affixed to the piston 56 while the
lateral connecting rods 74,76 are affixed to the piston 60
at two spaced locations situated on a diameter of the
piston 60.
The crankpins 68c,70c,72c can be considered to constitute
carrying elements for the respective connecting rods
74,76,78.
The lateral connecting rods 74,76 have the same
dimensions. As seen in FIGS. 2a-2g, the thickness of the
lateral connecting rods 74,76 is one-half that of the
central connecting rod 78 which otherwise has the same
dimensions as the lateral connecting rods 74,76.
The pistons 56,60 have the same mass while the total mass
of the lateral connecting rods 74,76 equals the mass of
the central connecting rod 78. Moreover, the various
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mounting elements employed to properly affix the lateral
connecting rods 74,76 to the piston 60 and the lateral
crankpins 68c,7oc have the same total mass as the mounting
elements employed to properly affix the central connecting
5 rod 78 to the piston. 56 and the central crankpin 72c. By
virtue of this design, a uniform mass distribution exists
for the pistons 56,60, the crank arrangement 66, the
connecting rods 74,76,78 and the mounting elements about a
first plane normal to the axis of and bisecting the
10 crankpin 72c. In addition, a uniform mass distribution
exists about a second plane perpendicular to the first
plane and containing the rotational axis R. Thus, the
mass on either side of the first plane is the same as is
the mass on either side of the second plane. Accordingly,
15 a dynamic mass balance is achieved and yaw vibrations are
eliminated or virtually eliminated.
The crankshaft 64, connecting rods 74,76,78 and mounting
elements together constitute a means for reciprocating the
pistons 56,60. The pistons 56,60, which are coaxial, are
reciprocated in such a manner that the pistons 56,60
travel towards and reach the respective top dead centers
simultaneously. Likewise, the pistons 56,60 travel
towards and reach the respective bottom dead centers
simultaneously.
The crankcase chamber 22 is preferably designed so that
the dimensions thereof are minimized. Advantageously, the
dimensions of the crankcase chamber 22 equal the
dimensions of the crank arrangement 66 plus just enough
clearance for unimpeded rotation of the crank arrangement
66. The coaxiality of the pistons 56,60, aside from
reducing or eliminating yaw vibrations, allows the
smallest possible crankcase volume to be obtained.
The engine 10 can operate on a mixture of fuel and air,
and this mixture may be used to cool the crankpins
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68c,70c,72c as well as journals which support the
crankshaft 64 for rotation. Moreover, a small quantity of
oil, e.g., 1/2 percent to 2 percent by volume, may be
added to the fuel. The mixture of air, fuel and oil,
which will be referred to as the fuel mixture, can
additionally function to lubricate the bearings for the
crankpins 68c,70c,?2c and for the journals supporting the
crankshaft 64. It is preferred for the oil incorporated
in the mixture to be biodegradable.
Referring to FIG. 5 together with FIG. 4, the crankshaft
64 has two journals or carrying elements 114 and 116 which
support the crankshaft 64 for rotation on the rotational
axis R. The journal 114 projects from the crank arm 68a
to one side of the crank arrangement 66 while the journal
116 projects from the crank arm 70a to the opposite side
of the crank arrangement 66. The journals 114,116 are
coaxial and share the common axis R.
The journal 126 is formed with an extension 118 of smaller
diameter than the journal 116. The extension 128, which
is coaxial with the journal 116, is provided with external
threads 218a to permit connection of the crankshaft 64 to
an accessory. Portions of the threads 118a have been
omitted for clarity. The journal 2I4 can have an
extension similar to that of the journal 226.
A chamber or cavity 120, e.g., a plenum chamber, is
located internally of the journal 226. The journal 226
has a cylindrical external bearing surface 226a, and a
duct 222 extends radially from the internal chamber 220 to
the bearing surface 216a. The internal chamber 220
further opens to an internally threaded axial passage 124
in the threaded extension 218. During operation, the
axial passage 224 is closed by an externally threaded plug
126 which is screwed into the passage 122.
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The journal 224 and its extension may likewise be provided
with an internal chanber and axial passage, respectively.
A chamber or cavity 128 is formed internally of the
crankpin 68c while a chamber 130 is formed internally of
the crankpin 70c. The chambers 128,130 may, for example,
constitute plenum chambers. The internal chamber 128 in
the crankpin 68c may project into the adjoining crank arms
68a,68b as shown and, as also shown, the internal chamber
130 in the crankpin 70c may extend into the neighboring
crank arms 70a,70b. The crankpin 68c has a cylindrical
external bearing surface 68d which is connected to the
internal chamber I28 by a radial duct 132 while the
crankpin 70c has a cylindrical external bearing surface
70d which is connected to the internal chamber 130 by a
radial duct 234.
The crankpin 72c is likewise provided with an internal
chamber or cavity 136, e.g., a plenum chamber, and the
ZO internal chamber 236 can project into the adjoining crank
arms 68b,70b as illustrated. The crankpin 70c has a
cylindrical external bearing surface 78d, and a duct 238
extends radially from the internal chamber 136 to the
bearing surface 78d.
The internal chambers 228,130,136 need not be located in
the crankpins 68c,70c,72c. Instead, the portions of the
connecting rods 74,76,78 adjacent to the crankpins
68c,70c,72c may be formed with internal chambers.
Each of the journals 124,126 rotates in a cylindrical
bearing sleeve or bearing element having two open ends
which are located opposite one another and are spaced from
each other longitudinally ar axially of the bearing
sleeve. The two open ends of the bearing sleeve can thus
be considered axial or longitudinal ends of the bearing
sleeve.
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Turning to FIG. 6 in conjunction with FIG. 5, a bearing
sleeve for the journals 214,226 is identified by the
numeral 240. The bearing sleeve 140 has an internal
bearing surface 240a which is designed to face the
external bearing surface 116a of the journal 116 or the
external bearing surface of the journal 114. The internal
bearing surface 140a is pravided with a series of
regularly spaced channels or grooves 142 which are
parallel to one another. The channels 142 run axially or
longitudinally of the bearing sleeve 140, that is, the
channels 242 run in a direction from one longitudinal end
of the bearing sleeve 140 towards the other. The internal
bearing surface 140a is further provided with an annular
channel or groove 144 which extends circumferentially of
the bearing sleeve 140 and intersects each of the
longitudinal channels 242. In FIG. 6, the annular channel
144 intersects the longitudinal channels 142 at an angle
of 90 degrees.
A bearing sleeve 140 is mounted on the journal 116 with
the annular channel 244 passing over the radial duct 222.
A second bearing sleeve 140 is mounted on the journal 114
in the same manner.
Referring to FIGS. 5 arid 7, each of the crankpins 68c,70c
rotates in a cylindrical bearing sleeve or bearing element
146 which again has two open ends located opposite one
another and spaced from each other longitudinally or
axially of the bearing sleeve 146. The bearing sleeve 146,
which must fit between the crank arms 68a,68b or the crank
arms 70a,70b, is shorter than the bearing sleeve 240.
The bearing sleeve 146 has an internal bearing surface
146a which is designed to face the external bearing
surface 68d of the crankpin 68c or the external bearing
surface 70d of the crankpin 70c. The internal bearing
surface 146a is provided with a series of regularly spaced
channels or grooves 148 which are parallel to one another
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and run axially yr longitudinally of the bearing sleeve
146. The internal bearing surface 146a is further
provided with an annular channel or groove 150 which
extends circumferentialiy of the bearing sleeve 146 and
intersects each of the longitudinal channels 148. In FIG.
7, the annular channel 150 intersects the longitudinal
channels 148 at an angle of 90 degrees.
A bearing sleeve 146 is mounted on the crankpin 68c with
the annular channel 150 passing over the radial duct 132.
A second bearing sleeve 146 is mounted on the crankpin 70c
with the annular channel 15o running over the radial duct
134.
Considering FIGS. 5 and 8, the crankpin 72c rotates in a
cylindrical bearing sleeve or bearing element 152 which,
as before, has two open ends located opposite one another
and spaced from each other longitudinally or axially of
the bearing sleeve 152. The bearing sleeve 152 must, fit
between the crank arms 68b,70b and, since the distance
between the crank arms 68b,?Ob is greater than the
distance between the crank arms 68a,68b or the crank arms
70a,70b, the bearing sleeve 152 can be longer than the
bearing sleeve 146.
The bearing sleeve 152 has an internal bearing surface
152a which is designed to face the external bearing
surface 72d of the crankpin 72c. The internal bearing
surface 152a is provided with a series of regularly spaced
channels or grooves 154 which are parallel to one another
and run axially or longitudinally of the bearing sleeve
152. The internal bearing surface 152a is further
provided with an annular channel or groove 156 which
extends circumferentially of the bearing sleeve 152 and
intersects each of the longitudinal channels 154. In FIG.
8, the annular channel 156 intersects the longitudinal
channels 154 at an angle of 90 degrees.
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The bearing sleeve 152 is mounted on the crankpin 72c with
the annular channel ;I56 passing over the radial duct 138.
FIG. 9, where the same numerals as in FIG, 5, plus 100,
are used to identify similar elements, illustrates a
crankshaft 164 which differs from the crankshaft 64 of
FIG. 5.
As shown in FIG. 9, the journal 214 of the crankshaft 164
has an extension 158 of smaller diameter than the journal
214. While the extension 118 of the crankshaft 64 is
provided with threads 118a for connection of the
crankshaft 64 to an accessory, the extension 158 of the
crankshaft 164 is formed with splines 160 for this
purpose. Moreover, the internal chamber 120 of the
crankshaft 64, as well as the adjoining passage 124, are
omitted in the crankshaft 164. Instead, the crankshaft
164 is provided with a circular chamber 162, e.g., a
plenum chamber, which is disposed in the region of the
junction between the journal 214 and its extension 158,
i . a . , at the end of the journal 214 remote from the crank
arm 168a to which the journal 214 is attached. The
circular chamber 162 circumscribes part of the journal 214
and part of the extension 158.
The bearing sleeve for the journal 214 can resemble the
bearing sleeve 140 of FIG. 6 except that the annular
circumferentially extending channel 144 may be omitted.
Thus, the annular channel 144 establishes a connection
between the longitudinal channels 142. Since such a
connection can be established in the crankshaft 164 by
having the longitudinal channels open to the circular
chamber 162, the annular channel 144 becomes unnecessary.
The longitudinal channels in the bearing sleeve for the
journal 214 can then run the length of the bearing sleeve.
The journal 216 of the crankshaft 164 can have an
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extension with splines like the journal 214 or an
extension with threads like the journal 116 of the
crankshaft 64. Furthermore, the journal 216 can be
provided with a circular chamber such as the chamber 162
of the journal 214 or with an internal chamber similar to
the chamber 120 of the crankshaft 64.
In FIG. 10, the same numerals as in FIGS. 1 and 2a-2g
denote similar elements.
FIG. 10 shows another bearing element 174 for the journals
114,116 of the crankshaft 64 or the journals 214,216 of
the crankshaft 164. The bearing element 174 is supported
in a bearing carrier 176 which, in turn, is mounted in the
front wall 14 of the engine casing 12. The bearing
carrier 176 extends from the outer surface of the front
wall 14 to the inner surface thereof which faces the
crankcase chamber 22.
The bearing element 174 includes a cylindrical wall 174a
which is received in the bearing carrier 176 and defines a
mounting passage 178 for a journal 114,116,214,216. The
mounting passage 178 has an axial or longitudinal end 178a
which confronts the crankcase chamber 22 and an opposite
axial or longitudinal end 178b remote from the crankcase
chamber 22. At the longitudinal end 178a, the cylindrical
bearing wall 174a is provided with an annular thrust
flange 174b projecting radially outward from the bearing
wall 174a.
The bearing carrier 176 has an end surface 176a facing the
crankcase chamber 22. The end surface 176a is formed with
an annular cutout which receives the thrust flange 174b of
the bearing element 174.
The cylindrical bearing wall 174a is provided with a
cylindrical cavity 180 which runs the length of the
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bearing wall 174a and circumscribes the mounting passage
178. The cylindrical cavity 180 intersects an annular
cavity 182 which is formed in the thrust flange 174b and
extends from the cylindrical bearing wall 174a to the
radially outer edge of the thrust flange 174b. At this
edge of the thrust flange 174b, the annular cavity 182
opens to the crankcase chamber 22.
With reference again to FIG. 1, a sprocket or rotating
element 80 is mounted on the crankshaft 64 externally of
the engine casing 12. The crankshaft sprocket 80 is
engaged by two endless transmitting members 82 and 84
which can, for example, be in the form of cog belts. The
transmitting member 82 extends around and engages the
l5 valve drive sprocket 52 for the valve mechanism 28 while
the transmitting member 84 extends around and engages the
valve drive sprocket 52 for the valve mechanism 30. Thus,
the transmitting members 82,84 function to transmit the
rotational motion of the crankshaft 64 to the rotatable
valve members 32 which are accordingly rotated by the
crankshaft 64.
A throttle body 86 is mounted on the engine casing 12, and
an injector or carburetor 88 is disposed between the
throttle body 86 and the casing 12. The injector or.
carburetor 88 is arranged to introduce fluid in the form
of a mixture of air and atomized fuel and oil into the
crankcase chamber 22 and constitutes a means for admitting
fluid into the chamber 22.
Considering FIGS. 2a-2g together with FIG. 1, the top wall
18 of the engine casing 12 is provided with an inlet
opening 90 for the introduction of the fuel mixture into
the crankcase chamber 22. A one-way element 92, e.g., a
reed valve, controls the flow of the fuel mixture through
the inlet opening 90.
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The bottom wall 20 of the engine casing 12 is provided
with an outlet opening 94 for the evacuation of the fuel
mixture from the crankcase chamber 22. The flow of the
fuel mixture through the outlet opening 94 is controlled
by a one-way element 96 which can again be a reed valve,
for example.
A transfer tube or conduit 98 leads from the outlet
opening 94 to the valve mechanism 28 located at the
longitudinal end 24b of the cylinder bore 24. A secand
transfer tube or conduit 100 leads from the outlet opening
94 to the valve mechanism 30 located at the longitudinal
end 26b of the cylinder bore 26.
Turning to FIG. 3 in conjunction with FIG. 1, the transfer
tube 98 has a banjo-like end with an annular portion 98a.
The annular tube portion 98a encircles the receiving ports
42 of the rotatable valve member 32 constituting part of
the valve mechanism 28. The fuel mixture traveling
through the transfer tube 98 enters the annular tube
portion 98a and then flows through the receiving ports 42
into the interior of the intake section 36 of the
rotatable valve member 32. The annular tube portion 98a
distributes the fuel mixture to the various receiving
ports 42.
The annular tube portion 98a is provided with one or more
flanges 102. The flange or flanges 102 allow the annular
tube portion 98a to be fastened to the cylinder head 106
by one or more fastening elements 104 such as bolts.
As illustrated in FIG. 1, the transfer tube 100 also has a
banjo-like end with an annular portion 100a. The annular
tube portion 100a circumscribes the receiving ports 42 of
the rotatable valve member 32 forming part of the valve
mechanism 30. The fuel mixture traveling through the
transfer tube 100 enters the annular tube portion 100a and
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then flows through the receiving ports 42 into the
interior of the intake section 36 of the rotatable valve
member 32. The annular tube portion 100a distributes the
fuel mixture to the various receiving ports 42.
Similarly to the annular tube portion 98a of the transfer
tube 98, the annular tube portion 100a of the transfer
tube 100 is provided with one or more flanges for
attachment of the annular tube portion 100a to the
cylinder head 110. The flange or flanges of the annular
tube portion 100a are not visible in FIG. 1.
The crankcase chamber 22 is arranged to communicate with
the injector or carburetor 88 by way of the valve 92 and
with the transfer tubes 98,100 by way of the valve 96.
The crankcase chamber 22 is further arranged to
communicate with the portion of each cylinder bore 24,26
located on the same side of the respective piston 56,60 as
the crankcase chamber 22. Otherwise, the crankcase
chamber 22 is sealed.
The operation of the engine 10 will be described with
reference to FIGS. 2a-2g. In this description, the arrows
E and I indicate only whether the fuel mixture is entering
or leaving the cylinder bares 24,26. The actual
directions of flow outside of the cylinder bores 24,26
will differ from the directions denoted by the arrows E
and I.
Considering FIG. 2a, the pistons 56,60 are just beginning
to move away from bottom dead center. The valve 96 and
the valve mechanism 30 are closed. On the other hand, the
valve 92 has opened, and the same is true for the exhaust
section 38 of the valve mechanism 28 as indicated by the
arrow E.
As the pistons 56,60 travel towards top dead center, a
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vacuum is created in the crankcase chamber 22 and the
adjoining portions of the cylinder bores 24,26. A mixture
of air and atomized fuel from the injector or carburetor
88 is drawn into the crankcase chamber 22 and the
adjoining portions of the cylinder bores 24,26 through the
inlet opening 90. The volume of fuel mixture drawn into
the crankcase chamber 22 and the adjoining portions of the
cylinder bores 24,26 is equal to the sum of the
displacements of the pistons 56,60. When the pistons
56,60 reach top dead center, the valve 92 and the valve
mechanism 28 close.
In FIG. 2b, the pistons 56,60 have just begun to move away
from top dead center. The valve 92 and the valve
mechanism 30 are closed whereas the valve 96 and the
intake section 36 of the valve mechanism 28 have opened.
The arrow I denotes that the intake section 36 of the
valve mechanism 28 is open.
As the pistons 56,60 travel towards bottom dead center,
the pistons 56,60 compress the fuel mixture previously
drawn into the crankcase chamber 22 and the adjoining
portions of the cylinder bores 24,26. At the same time,
the pistons 56,60 force the compressed fuel mixture
through the opening 94, the transfer tube 98 and the
intake section 36 of the valve mechanism 28 into the
longitudinal end 24b of the cylinder bore 24. The piston
56 is on an intake stroke, and the fuel mixture flowing
through the longitudinal end 24b enters the portion of the
cylinder bore 24 which serves as a combustion chamber.
Due to unavoidable frictional losses, the volume of fuel
mixture fed into the combustion chamber of the cylinder
bore 24 is slightly less than the sum of the displacements
of the pistons 56,60. However, this volume is
significantly greater than the displacement of the piston
56 alone or the displacement of the piston 60 alone. Once
the pistons 56,60 reach bottom dead center, the valve 96
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and the valve mechanism 28 close.
Turning to FIG. 2c, the pistons 56,60 are just beginning
to move away from bottom dead center. The valve 96 and
the valve mechanism 28 remain closed while the valve 92
and the exhaust section 38 of the valve mechanism 30 have
opened. The opening of the exhaust section 38 of the
valve mechanism 30 is indicated by the arrow E.
As the pistons 56,60 move towards top dead center, a new
quantity of fuel mixture equal to the sum of the
displacements of the pistons 56,60 is drawn into the
crankcase chamber 22 and the adjoining portions of the
cylinder bores 24,2Ei. The piston 56 is on a compression
stroke and compresses the fuel mixture in the combustion
chamber of the cylinder bore 24. This compression in the
combustion chamber of the cylinder bore 24 constitutes an
additional compression of the fuel mixture since such fuel
mixture was compressed previously. When the pistons 56,60
reach top dead center, the valve 92 and the valve
mechanism 30 close arid the spark plug 58 fires to ignite
the fuel mixture in the combustion chamber of the cylinder
bore 24.
Referring to FIG. 2d, the pistons 56,60 have just begun to
move away from top dead center. The valve 92 and the
valve mechanism 28 remain closed whereas the valve 96 and
the intake section 36 of the valve mechanism 30 have
opened. Opening of the intake section 36 of the valve
mechanism 30 is denoted by the arrow I. The piston 56 is
on a power stroke.
As the pistons 56,60 travel away from top dead center, the
pistons 56,60 compress the new fuel mixture in the
crankcase chamber 22 and the adjoining portions of the
cylinder bores 24,26. Concurrently, the pistons 56,60
force the new fuel mixture through the opening 94, the
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transfer tube 100, the intake section 36 of the valve
mechanism 30 and the longitudinal end 26b of the cylinder
bore 26. The piston 60 is on an intake stroke, and the
fuel mixture flowing through the longitudinal end 26b
enters the portion of the cylinder bore 26 which serves as
a combustion chamber. Due to unavoidable frictional
losses, the volume of fuel mixture fed into the combustion
chamber of the cylinder bore 26 is slightly less than the
sum of the displacements of the pistons 56,60. However,
this volume is significantly greater than the displacement
of the piston 56 alone or the displacement of the piston
60 alone. Once the pistons 56,60 reach bottom dead
center, the valve 96 and the valve mechanism 30 close.
Considering FIG. 2e, the pistons 56,60 are just beginning
to move away from bottom dead center. The valve 96 and
the valve mechanism 30 remain closed while the valve 92
and the exhaust section 38 of the valve mechanism 28 have
opened. The arrow E indicates that the exhaust section 38
of the valve mechanism 28 is open.
As the pistons 56,60 move towards top dead center, an
additional quantity of fuel mixture equal to the sum of
the displacements of the pistons 56,60 is drawn into the
crankcase chamber 22 and the adjoining portions of the
cylinder bores 24,26. The piston 56 is on an exhaust
stroke and pushes the products of the earlier combustion
in the combustion chamber of the cylinder bore 24 out of
this combustion chamber through the exhaust section 38 of
the valve mechanism 28. The piston 60, on the other hand,
is on a compression stroke and compresses the fuel mixture
in the combustion chamber of the cylinder bore 26. This
compression in the combustion chamber of the cylinder bore
26 constitutes an additional compression of the fuel
mixture since such fuel mixture was compressed previously.
When the pistons 56,60 reach top dead center, the valve 92
and the valve mechanism 28 close and the spark plug 62
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fires to ignite the fuel mixture in the combustion chamber
of the cylinder bore 26.
Turning to FIG. 2f, the pistons 56,60 have just begun to
move away from top dead center. The valve 92 and the
valve mechanism 30 remain closed whereas the valve 96 and
the intake section 36 of the valve mechanism 28 have
opened. The opening of the intake section 36 of the valve
mechanism 28 is denoted by the arrow I. The piston 60 is
on a power stroke.
As the pistons 56,60 travel away from top dead center, the
pistons 56,60 compress the fuel mixture most recently
admitted into the crankcase chamber 22 and the adjoining
portions of the cylinder bores 24,26. At the same time,
the pistons 56,60 force this fuel mixture through the
opening 94, the transfer tube 98, the intake section 38 of
the valve mechanism 28 and the longitudinal end 24b of the
cylinder bore 24. The piston 56 is again on an intake
stroke, and the air/fuel mixture flowing through the
longitudinal end 24b enters the portion of the cylinder
bore 24 which serves as a combustion chamber. As before,
the volume of fuel mixture introduced into the combustion
chamber of the cylinder bore 24 is significantly greater
than the displacement of the piston 56 alone or the
displacement of the piston 60 alone. Once the pistons
56,60 reach bottom dead center, the valve 96 and the valve
mechanism 28 close.
Referring to FIG. 2g, the pistons 56,60 are just beginning
to move away from bottom dead center. The valve 96 and
the valve mechanism 28 remain closed while the valve 92
and the exhaust section 38 of the valve mechanism 30 have
opened. The opening of the exhaust section 38 of the
valve mechanism 30 is indicated by the arrow E.
As the pistons 56,60 move towards top dead center, yet
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another quantity of fuel mixture equal to the sum of the
displacements of the pistons 56,60 is drawn into the
crankcase chamber 22 and the adjoining portions of the
cylinder bores 24,26. The piston 60 is on an exhaust
stroke and pushes the products of the earlier combustion
in the combustion chamber of the cylinder bore 26 out of
this combustion chamber through the exhaust section 38 of
the valve mechanism 30. In contrast, the piston 56 is on
a compression stroke and compresses the fuel mixture which
has just entered the combustion chamber of the cylinder
bore 24. This compression in the combustion chamber of
the cylinder bore 24 constitutes an additional compression
of such fuel mixture since the latter was compressed
previously. When the pistons 56,60 reach top dead center,
the valve 92 and the valve mechanism 30 close and the
spark plug 58 fires to ignite the fuel mixture in the
combustion chamber of the cylinder bore 24. The operating
sequence now reverts to FIG. 2d and is repeated while the
engine 10 runs.
Although the pistons 56,60 move towards top dead center
together and towards bottom dead center together, the
piston 56 and the piston 60 are 180 crankshaft degrees out
of phase. Thus, while one of the pistons 56,60 is on an
intake stroke, the other is on a power stroke. Similarly,
when one of the pistons 56,60 is on a compression stroke,
the other of the pistons 56,60 is on an exhaust stroke.
This arrangement is balanced and yields evenly spaced
firing impulses 360 degrees apart.
Since the volume of fuel mixture fed into the combustion
chamber of the cylinder bore 24 or 26 exceeds the
displacement of the respective piston 56 or 60, and since
the fuel mixture is compressed during introduction into
the combustion chamber and then again after introduction,
a supercharging effect is obtained. This supercharging
effect is achieved without a complicated fan or rotor
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mechanism. Furthermore, the effect is virtually free
inasmuch as it is based on the actions which occur during
routine operation of an engine. The supercharging effect
makes it possible for the horsepower and torque of the
engine 10 to be significantly increased at low cost. The
horsepower and torque of the engine 10 may be 40 to 45
percent greater than the horsepower and torque without
crankcase compression.
The fuel mixture drawn into the crankcase chamber 22 can
lubricate and cool the crankshaft bearing sleeves
140,146,162 and, in addition, can cool the undersides of
the pistons 56,60. This enables temperature gradients, as
well as the probability of detonation and piston failure,
to be greatly reduced. Moreover, the pump, sump and lines
normally required for the lubrication of crankshaft
bearing elements may be eliminated.
Returning to FIGS. 5-9, a charge or pulse of fresh fuel
mixture is periodically admitted into the crankcase
chamber 22 as the crankshaft 64 or 164 rotates. Since the
fuel in each charge has just undergone atomization or
evaporation, the charge is cold and can cool the entire
crankcase. The charge is under pressure, and a portion of
the charge flows into the longitudinal channels
142,148,154 of the respective bearing sleeves 140,146,152.
In the case of the crankshaft 64, the fuel mixture flowing
along the longitudinal channels 142,148,154 enters the
annular channels 144,150,156 and is then forced into the
internal chambers 120,128,130,138 under crankcase
pressure. On the other hand, in the crankshaft 164,
although the fuel mixture is introduced into the internal
chambers 228,230,238 by way of the annular channels
150,156, the mixture is fed into the circular chamber 162
directly from the longitudinal channels 142.
The pressurized fuel mixture in the internal chambers
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120,128,130,138 of the crankshaft 64 or, alternatively, in
the circular chamber 162 and internal chambers 228,230,238
of the crankshaft 164, flows out under reduced pressure
across the surfaces of the bearing sleeves such as the
sleeves 140,146,152.
Accordingly, a pressure-driven flow of fresh and cold fuel
mixture is delivered to the bearing surfaces in the
crankcase chamber 22 at least once during each revolution
of the crankshaft 64 or 164.
If the internal chambers 120,128,130,138,228,230,238 and
the circular chamber 162 should fill up with oil, they may
lose their function. Depending upon the circumstances,
the chambers 120,128,130,138,162,228,230,238 may be
connected to the low-pressure side of the throttle body by
a line or may be provided with drain passages which allow
oil to drain out by centrifugal force.
In normal engines, lubrication of the wrist pins does not
require special attention. However, since the engine 10
of the invention is a high-performance engine, enhanced
lubrication is desirable to reduce the temperature of the
pins and the piston crowns. To this end, the wrist pins
are hollow and have their ends plugged, e.g., with plastic
buttons, so that an internal chamber or plenurn chamber is
formed in each pin. To avoid scoring the wrist pins, the
pins are press-fit in the pistons 56,60 and rock in the
bushings which support the small ends of the connecting
rods 74,76,78. The bushings are provided with
longitudinal channels or grooves as well as a central
annular channel or groove which intersects the
longitudinal channels. Fuel mixture flowing into the
longitudinal channels of a bushing enters the central
annular channel from where the mixture is forced into the
respective wrist pin by way of a duct.
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Considering FIG. 10, cold fuel mixture is fed into the
cylindrical cavity 180 of the bearing element 174 under
pressure from at least one hole in the bearing carrier
176. The fuel mixture enters the cylindrical cavity 180
at the longitudinal end 178b of the mounting passage 178,
that is, at or near the area of the cylindrical cavity 180
which is farthest from the thrust flange 174b. The fuel
mixture is distributed circumferentially of the
cylindrical cavity 180 and travels the length of the
cylindrical bearing wall 174a to the annular cavity 182 in
the thrust flange 174b. The fuel mixture then flows
radially outward thraugh the annular cavity i82 and is
discharged into the crankcase chamber 22 with a reduction
in pressure.
Movement of the pistons 56,60 in diametrically opposite
directions permits the amplitudes of the torque reaction
and the exhaust pulses to be halved. Such movement also
permits the vibrations due to reciprocation of the piston
56 and the vibrations due to reciprocation of the piston
60 to cancel out almost entirely.
As mentioned previously, a uniform mass distribution
exists for the pistons 56,60, the crank arrangement 66,
the connecting rods 74,76,78 and the mounting elements for
the rods 74,76,78 about a first plane normal to the axis
of and bisecting the crankpin 72c. In addition, a uniform
mass distribution exists about a second plane
perpendicular to the first plane and containing the
rotational axis R. These uniform mass distributions
enable a dynamic mass balance to be achieved thereby
allowing yaw and its accompanying vibrations to be
entirely or almost entirely eliminated.
The large bore-to-stroke ratio permits piston speed to be
reduced. This, in turn, makes it possible to decrease
wear and internal stresses in, and to increase the life
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of, the engine 10. The large bore-to-stroke ratio further
allows volumetric and thermal efficiencies to be
increased. Such ratio additionally makes it possible to
reduce thermal gradients thereby enabling the likelihood
of detonation to be decreased.
The large bore-to-stroke ratio also permits the maximum
connecting rod angle to be reduced. This allows the
weights of the connecting rods 74,76,78, as well as the
IO functional length of the crankshaft 64, to be decreased.
In addition, side thrust and friction on the cylinder
walls is reduced. Consequently, stiffness is increased
and engine weight decreased. At the same time, friction
and the heat generated by the same are reduced thus
further decreasing the tendency for detonation.
As indicated earlier, the rotatable valve member 32 may be
one piece or an assembly and can be driven by a cog belt.
A valve system including the rotatable valve member 32 has
many advantages including several of great importance in
reducing or eliminating detonation. Among the advantages
of such a system are the fallowing:
1. The rotatable valve member 32 allows
temperature gradients to be reduced and hot spots to be
substantially eliminated thereby reducing the likelihood
of detonation. This is due to rotation of the warm
exhaust section 38 of the valve member 32 to the cooler
outer portion of the cylinder head during each operating
cycle.
2. When the rotatable valve member is one
piece, heat can flow from the warm exhaust section 38 to
the relatively cold intake section 36. This enables the
temperature gradient across the cylinder head and the
crown of the neighboring piston 56 or 60 to be reduced
thus further decreasing the likelihood of detonation.
3. The rotatable valve member 32 allows the
temperature at the exhaust side of the cylinder head to be
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decreased because the hot exhaust gases exit through the
valve member 32 rather than through a port in the actual
material of the cylinder head 106 or 110. If desired, the
internal surfaces of the exhaust section 38 of the valve
member 32 can be coated with a refractory material to
insulate the valve member 32 and the head from high heat
loads.
4. The rotatable valve member 32 can be
mounted so that it does not protrude into the adjoining
combustion chamber (as do poppet valves) thereby allowing
high compression ratios to be obtained.
5. The system is simple, reliable and self-
lubricating and seldom requires adjustment.
6. The operation of the system is not greatly
endangered by accidental overrevving which can quickly
damage a poppet valve engine.
7. The system is quiet.
8. The system permits the use of extremely
small combustion chamber volumes. This, in turn, makes it
possible to achieve the high compression ratios required
when alcohol and propane are to be used as fuels.
9. The rotatable valve member 32 can serve as
a structural element for stiffening the cylinder head 106
or 110.
10. The rotatable valve member 32 enables the
number of parts for transferring fluid from the crankcase
chamber 22 to the combustion chamber in one of the
cylinder bores 24 or 26 to be reduced from approximately
twenty to as little as two, namely, the valve member 32
itself and the transfer tube 98 or 100. The number of
parts could be greater than two if necessary or desirable,
e.g., the drive section 48 of the valve member 32 could be
made as a separate part.
11. The rotatable valve member 32 allows the
frontal area of the cylinder head to be significantly
reduced.
12. The power required to drive the rotatable
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valve member 32 varies directly with rpm whereas the power
required to drive a poppet valve varies as the square of
the rpm.
In FIG. 11, the same numerals as in FIGS. 1-3, plus 300,
identify similar elements.
FIG. 11 shows that a transfer tube 400 may include an
annular tube portion 400a and a separate conduit 400b such
as a hose. The annular tube portion 400a is connected to
the conduit 400b by a clamping arrangement 354.
The annular tube portion 400a is formed with a flange 356.
The flange 356 permits the annular tube portion 400a to be
attached to the cylinder head 410 by suitable fastening
elements 358, e.g., screws.
FIG. 11 also shows a rotatable valve member 332 which is
designed to undergo limited movement in axial or
longitudinal direction thereof. The rotatable valve
member 332 has an elongated valve element 334 which
differs from the elongated valve element 34 of FIG. 3 in
that the valve element 334 is provided with a radially
outward projecting annular flange 360 in the region of the
receiving ports 342. Furthermore, in the valve element
34, the additional section 48 and the longitudinal end 36a
of the intake section 36 have an outer diameter greater
than that of the exhaust section 38. In contrast, the
exhaust section 338 of the elongated valve element 334 has
the same outer diameter as the additional section 448 and
the longitudinal end 336a of the intake section 336.
Moreover, while the additional section 48 of the valve
element 34 is splined, the additional section 448 of the
valve element 334 is not.
The splines 50 in the additional section 48 of the
elongated valve element 34 establish a connection with the
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respective drive sprocket 52 which serves to rotate the
rotatable valve member 32. Thus, the drive sprockets 52
are provided with splines which mesh with the splines 50
of the respective elongated valve element 34. In FIG. 11,
the drive sprocket 352 is formed without splines and,
instead, has a connecting portion 352a for attachment of
the drive sprocket 352 to the elongated valve element 334.
The connecting portion 352a projects axially outward from
a toothed portion 352b which constitutes part of the drive
sprocket 352 and functions to engage an endless
transmitting member such as a cog belt.
The elongated valve element 334 has a cylindrical wall
334a which, at the end of the additional section 448
remote from the intake section 336 of the valve element
334, has a cylindrical end face directed away from the
intake section 336. The connecting portion 352a of the
drive sprocket 352 is attached to this end face by
fastening and adjusting elements 362, e.g., screws,
passing through slotted holes in the connecting portion
352a. The fastening and adjusting elements 362 serve not
only for attachment of the drive sprocket 352 to the
elongated valve element 334 but also for fine adjustment
of the timing of the rotatable valve member 332.
A disk 364 is inserted in the end of the additional
section 448 remote from the intake section 336 and closes
the elongated valve element 334 at such end. The disk 364
has a thickened central portion 364a provided with a
threaded opening. An externally threaded operating
element 366, e.g., a button-head bolt, extends through a
hole in the connecting portion 352a of the drive sprocket
352 and screws into the threaded opening of the disk 364.
The rotatable valve member 332 is slidable in axial or
longitudinal direction thereof relative to the cylinder
head 410 as well as to the drive sprocket 352, the
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fastening and adjusting elements 362 and the operating
element 366. In FIG. 11, the valve member 332 slides
horizontally, that is, from left-to-right and right-to-
left.
The annular flange 360 of the elongated valve element 334
is located inside the annular tube portion 400a of the
transfer tube 400 and has a major surface 360a which faces
away from the cylinder head 410. The major flange surface
360a is subjected to the pressure of the fuel mixture
flowing from the transfer tube 400 into the valve member
332. This pressure urges the rotatable valve member 332
towards the right as seen :in FIG. 11.
The annular flange 360 cooperates with the annular tube
portion 400a, the cylindrical wall 334a of the elongated
valve element 334 and the cylinder head 410 to define a
compartment 368 for at least one spring 370, e.g., a
spiral spring. The annular flange 360 has a second major
surface 360b which faces away from the major flange
surface 360a and confronts the compartment 368, and the
spring or springs 370 bear against the second major
surface 360b and against the cylinder head 410. The
spring or springs 370 urge the rotatable valve member 332
to the left as seen in FIG. 11.
Movement of the rotatable valve member 332 to the right is
limited by the spring or springs 370 which prevent further
movement when the force exerted on the major flange
surface 360b by the spring or springs 370 balances the
force exerted on the major flange surface 360a by the fuel
mixture. On the other hand, movement of the rotatable
valve member 332 to the left is limited by a stop or
abutment 372 formed on the inner surface of the annular
tube portion 400a of the transfer tube 400. Movement of
the rotatable valve member 332 to the left ceases when the
major flange surface 360a contacts the stop 372. In FIG.
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11, the rotatable valve member 332 is in its leftmost
position in which the major flange surface 360a bears
against the stop 372.
Axial or longitudinal movement of the rotatable valve
member 332 can occur even if the valve member 332 is
driven in rotation by meshing splines on the valve drive
sprocket 352 and the additional section 448 of the
elongated valve element 334. Movement of the valve member
332 under these conditions can, for instance, be
accommodated by designing the valve drive sprocket 352 and
the transmitting member, e.g., the cog belt, which engages
the same so that the width of the valve drive sprocket 352
exceeds the width of the transmitting member by an amount
equal to the desired displacement of the rotatable valve
member 332. By way of example, the rotatable valve member
332 can be arranged to move axially through a distance
equal or approximately equal to 0.25 inch or 6mm. This
distance may correspond to 75 percent of the width of the
discharge ports 344 in the elongated valve element 334.
The cylinder head 410 is formed with a series of outlet
ports 374 which have the same size and shape as, and are
equal in number to, the discharge ports 344. The
discharge ports 344 of the rotatable valve member 332 are
separated from one another by webs or bridges 344a while
the outlet ports 374 of the cylinder head 410 are
separated from each other by webs or bridges 374a
identical in size and shape, and equal in number, to the
webs 344a. The webs 344a,374a cooperate with one another
to change the effective port width as the rotatable valve
member 332 is shifted axially. The effective port width
is the dimension of the free area, considered widthwise of
the ports 344,374, which is available for flow of the fuel
mixture.
The rotatable valve member 332 is arranged so that the
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discharge ports 344 of the valve member 332 are exactly in
register with the outlet ports 374 of the cylinder head
410 when the valve member 332 is in its rightmost
position. This situation is depicted at A in FIG. 12
which illustrates that the webs 344a,374a are also exactly
in register. In the rightmost position of the rotatable
valve member 332, the effective port width EW is a maximum
and the entire width of the ports 344,374 is available for
the fuel mixture to flow through.
At B in FIG. 12, the rotatable valve member 332 has been
shifted slightly to the left from its rightmost position.
Neither the ports 344,374 nor the webs 344a,374a are
exactly in register any longer and a portion of each valve
port 344 is blocked by a web 374a of the cylinder head
410. The webs 344a,374a cooperate with one another to
reduce the effective part width EW from its maximum value.
At C in FIG. 12, the rotatable valve member 332 has been
shifted farther to the left, i.e., has been shifted left
from its position at B. The effective port width EW is
accordingly reduced from that at B.
The rotatable valve member 332 has assumed its leftmost
position at D in FIG. 12 and the effective port width EW
is a minimum.
The axial shifting of the rotatable valve member 332 is
intended to inhibit detonation and preignition.
Detonation is a phenomenon in which the fuel mixture is
too lean and ignites throughout its volume rather than
having flame-front burning characteristics. The result is
a sharp pressure rise which leads to high pressure loads
and high heat loads. Detonation, which is generally
audible as pinging, causes oil film erosion as well as the
erosion of valves, piston tops and the surfaces of the
combustion chambers. Detonation can also raise the
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temperature of spark plug points, valves and other exposed
and poorly cooled elements to such a degree that one or
more of these elements begins to ignite the fuel mixture
earlier than normal. This condition is known as pre-
y ignition and causes an immediate and noticeable power
loss. Pre-ignition additionally results in high pressure
loads and heat loads which rapidly break piston rings,
burn exhaust valves and melt piston tops thereby
destroying the engine.
l0
Detonation can occur when larger unvaporized fuel droplets
come out of suspension due to cold conditions and/or low
velocity of the fuel mixture. Detonation can take place
when an engine is warm or on start-up when an engine is
15 cold. In a warm engine, detonation may occur at low
speeds under load which is referred to as "lugging" or at
low to moderate speeds when the throttle is opened
suddenly thereby creating an increased demand for a normal
fuel mixture.
Returning to FIGS. 11 and 12, detonation can be inhibited
by imparting turbulence to the fuel mixture flowing from
the valve member 332 into the cylinder bore 326 and by
increasing the velocity of the mixture. Axial shifting of
the rotatable valve member 332, which can be carried out
manually or automatically, makes it possible to induce
turbulence in the fuel mixture.
Assuming that the engine of the invention is running at
maximum horsepower and rpm, automatic operation of the
valve member 332 is as follows:
At maximum horsepower and rpm, the fuel mixture entering
the annular tube portion 400a of the transfer tube 400 is
at a pressure sufficiently high to overcome the resistance
of the spring or springs 370 acting on the annular flange
360 of the elongated valve element 334. Consequently, the
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rotatable valve member 332 is in its rightmost position
where, as shown at A in FIG. 12, the valve ports 344 are
in exact register with the head ports 374. The effective
port width EW is at a maximum and the fuel mixture flowing
through the ports 344,374 experiences little turbulence.
However, inasmuch as the engine is hot and the fuel
mixture has a high velocity, turbulence is unnecessary
because fuel droplets do not tend to come out of
suspension arid the likelihood of detonation is low.
If the operator of the engine now throttles back slightly,
the velocity of the fuel mixture decreases somewhat.
Accordingly, the tendency of fuel droplets to come out of
suspension begins to increase as does the likelihood of
detonation. The pressure of the fuel mixture in the
annular tube portion 400a of the transfer tube 400
decreases slightly as the engine is throttled back and the
spring or springs 370 are able to shift the rotatable
valve member 332 towards the left. At B in FIG. 12, the
force exerted on the annular flange 360 of the elongated
valve element 334 by the spring or springs 370 equals the
force exerted by the fuel mixture of reduced pressure.
The effective port width EW is reduced somewhat from its
maximum value and the webs 344a,374a of the elongated
valve element 334 and cylinder head 410 create small steps
or discontinuities in the flow paths of the fuel mixture.
Hence, a small degree of turbulence is induced in the fuel
mixture passing through the ports 344,374 and the velocity
of the mixture is increased somewhat. The tendency of
fuel droplets to come out of suspension decreases with an
accompanying a decrease in the likelihood of detonation.
Should the engine be throttled back farther so that the
tendency of fuel droplets to come out of suspension
increases from slight to moderate, the spring or springs
370 shift the rotatable valve member 332 more to the left
from the position indicated at B in FIG. 12 to that
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indicated at C. The spring or springs 370 can shift the
rotatable valve member 332 farther leftward because the
pressure of the fuel mixture undergoes an additional
decrease as the engine is throttled back again. The
effective port width EW is reduced from that at B and the
steps or discontinuities formed by the webs 344a,374a are
enlarged. Consequently, a moderate degree of turbulence
and a moderate increase in velocity are imparted to the
fuel mixture traveling through the ports 344,374 to
counteract the moderate tendency of fuel droplets to come
out of suspension.
When the engine is idling and the tendency of fuel
droplets to come out of suspension is high, the spring or
springs 370 urge the rotatable valve member 332 to its
leftmost position. In this position, which is shown at D
in FIG. 12, the effective port width EW is a minimum and
the steps or discontinuities created by the webs 344a,374a
are of maximum size. As a result, the degree of
turbulence induced in the fuel mixture flowing through the
ports 344,374 is maximized and the velocity of the mixture
is increased substantially. Detonation is inhibited even
when the throttle is opened suddenly.
Since the energy for moving the rotatable valve member 332
comes from the spring or springs 370 and from the pressure
of the fuel mixture, the energy is essentially free.
As indicated earlier, it is possible to manually move the
rotatable valve member 332 axially. This can be
accomplished by attaching one end of a push-pull cable,
which can shift the rotatable valve member left and right,
to the operating element 366. The other end of the cable
can be connected to a lever which is movable by hand
between "Start & Idle", "Midrange" and "Performance's
settings. Under such circumstances, the spring or springs
370, the stop 372 and the annular flange 360 on the
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elongated valve element 334 may be eliminated.
A significant advantage of an oval or approximately oval
shape for the ports 344,374 resides in that duration is
progressively reduced as the engine is throttled back.
This is due to the fact that not only the effective port
width EW but also the effective port length decreases as
the rotatable valve member 332 moves to the left. The
effective port length is the length of the free area,
considered lengthwise of the ports 344,374, which is
available for flow of the fuel mixture. A progressive
reduction in duration with decreasing engine speed enables
smooth running to be achieved throughout the useful rpm
range of the engine. Moreover, such a progressive
reduction in duration allows strong midrange performance
as well as a strong steady idle to be obtained and permits
the engine to ''tractor" at idle and trolling speeds.
It is possible to bias or angle the ports 374 of the
cylinder head 410 in such a manner that the fuel mixture
is caused to swirl. This further reduces the tendency of
fuel droplets to come out of suspension.
During automatic axial shifting of the rotatable valve
member 332, there will be a slight delay in movement of
the valve member 332 due to inertia. This allows the
incoming fuel mixture to fill the transfer tube 400 and
the intake section 336 of the rotatable valve member 332
before the valve ports 344 open thereby preventing a lean
idle mixture from causing detonation when the throttle is
opened suddenly. A delay can also be achieved where the
rotatable valve member 332 is manually shifted in axial
direction thereof by inserting a delaying device in the
push-pull cable used to move the valve member 332.
In a conventional engine, there is only one set of
conditions where rpm, throttle position, flow rate of the
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fuel mixture, turbulence, torque and horsepower are
optimal. The design of the rotatable valve member 332 and
the mounting of the latter for axial movement allow
optimal conditions to be achieved more broadly over the
operating range of the engine of the invention. This is
demonstrated by a very strong steady idle, high torque at
low rpm and an abundance of power at high rpm. An engine
without the variable port timing obtainable with the
rotatable valve member 332 cannot possess such
flexibility. The usable rpm range of the engine of the
invention may be increased by 20 to 30 percent at a cost
increase of 1 to 2 percent.
The rotatable and axially shiftable valve member 332 not
only allows more efficient port timing to be obtained but
induces the correct amount of turbulence for each speed
range thereby enabling the danger of detonation to be
reduced.
When the intake section 36,336 of a rotatable valve member
32,332 closes, a certain quantity of pressurized fuel
mixture is trapped in the transfer tube 98,100,400. When
the discharge ports 44,344 again open, the trapped fuel
mixture permits earlier and heavier charging of a
combustion chamber to be obtained with an accompanying
increase in efficiency. In fact, charging of a combustion
chamber can begin even before the start of the intake
stroke.
The engine in accordance with the invention makes it
possible to achieve an increased ratio of horsepower to
weight, an increased ratio of horsepower to unit
displacement, and an increased ratio of horsepower per
unit of fuel consumed. Moreover, the engine is relatively
simple, lightweight and silent and has relatively few
parts. In addition, the engine is capable of generating
high torque and is able to run without detonation or
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preignition even on low-grade fuels. The engine also
allows good fuel efficiency to be obtained and requires no
exotic materials or processes. Further, the engine can be
built in an ordinary automotive machine shop.
The engine of the invention can be used for different
applications. For instance, the engine can be employed in
motor vehicles, pumps, generators, farm implements and
manufacturing plants as well as for various military
applications such as drones and unmanned surveillance
craft.
Various modifications are possible within the meaning and
range of equivalence of the appended claims.
