U.S. patent application number 12/311561 was filed with the patent office on 2010-01-14 for oil seal.
Invention is credited to Edward Charles Mendler.
Application Number | 20100006057 12/311561 |
Document ID | / |
Family ID | 39268960 |
Filed Date | 2010-01-14 |
United States Patent
Application |
20100006057 |
Kind Code |
A1 |
Mendler; Edward Charles |
January 14, 2010 |
Oil seal
Abstract
According to the present invention, a variable compression ratio
machine having main bearings mounted in an eccentric carrier or
support includes an oil seal located primarily in a main bearing
cap for minimizing leakage of pressurized main bearing oil. The
seal is located generally in a first main bearing fastener socket
or fastener access cutout in order to minimize structurally
compromising the bearing cap, and a portion of the fastener socket
preferably is used as an oil passageway as well as for wrench
access to the fastener. The oil seal and oil circuit of the present
invention enable the size of the eccentric support to be minimized
while also providing highly effective oil sealing. In more detail,
a significant advantage of the present invention is that highly
effective oil sealing is attained without compromising the size or
structural integrity of the bearing cap. A second significant
advantage of the present invention is that it can be manufactured
and assembled at low cost. The oil sealing system of the present
invention is robust and highly reliable.
Inventors: |
Mendler; Edward Charles;
(Mill Valley, CA) |
Correspondence
Address: |
Charles Mendler
7 Millside Lane
Mill Valley
CA
94941
US
|
Family ID: |
39268960 |
Appl. No.: |
12/311561 |
Filed: |
September 25, 2007 |
PCT Filed: |
September 25, 2007 |
PCT NO: |
PCT/US2007/020640 |
371 Date: |
April 1, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60849314 |
Oct 3, 2006 |
|
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|
Current U.S.
Class: |
123/196R |
Current CPC
Class: |
F02B 75/047
20130101 |
Class at
Publication: |
123/196.R |
International
Class: |
F01M 11/02 20060101
F01M011/02 |
Claims
1. An oil circuit for a variable compression ratio mechanism having
a range of compression ratio settings, and having an oil supply, a
housing and at least one cylinder mounted in the housing, a piston
mounted for reciprocating movement in the cylinder, a crankshaft
defining an axis about which the crankshaft rotates, and a
connecting rod connecting the piston to the crankshaft, said
variable compression ratio mechanism further having at least one
eccentric support for supporting the crankshaft about the
rotational axis of the crankshaft, the eccentric support being
mounted in the housing for pivoting relative to the housing about a
pivot axis, the pivot axis being substantially parallel to and
spaced from the rotational axis of the crankshaft, and main
bearings mounted in the eccentric support for supporting the
crankshaft, said eccentric support further including a bearing cap
and a plurality of fasteners for retaining the crankshaft in the
eccentric support, said bearing cap further including a bearing
socket for retaining one or more of said main bearings in the
eccentric support, said eccentric support further having a first
fastener access cutout, a housing oil feed line in said housing,
said housing oil feed line having an upstream end, said upstream
end being in fluid communication with the oil supply, and a down
stream end, said down stream end being in fluid communication with
said first fastener access cutout, wherein said oil circuit further
has an eccentric oil feed line in said eccentric support, said
eccentric oil feed line having an upstream end, said upstream end
being connected to said first fastener access cutout, and a down
stream end, said down stream end being in fluid communication with
said main bearings, wherein said oil supply is in fluid
communication with said first fastener access cutout through said
housing oil feed line, and said first fastener access cutout is in
fluid communication with said main bearings through said eccentric
oil feed line, wherein said oil circuit further has a sealing
curtain area around said first fastener access cutout, and sealing
means for providing a small curtain area for providing minimal oil
leakage between said housing oil feed line and said eccentric oil
feed line, thereby providing an oil supply circuit for delivering
oil from the oil supply to the main bearings with minimal oil
leakage.
2. The oil circuit of claim 1 further including an oil seal for
substantively minimizing leakage of oil between the housing oil
feed line and the eccentric oil feed line, said seal being mounted
on said eccentric support.
3. The oil circuit of claim 1 further including an oil seal for
substantively minimizing leakage of oil between the housing oil
feed line and the eccentric oil feed line, said seal being located
generally in said first fastener access cutout.
4. The oil circuit of claim 3, wherein said first fastener access
cutout includes retaining means for retaining said oil seal in
location.
5. The oil circuit of claim 3, further having a first fastener
socket, and said oil seal further includes a boss, said boss being
positioned in said first fastener socket for retaining said oil
seal in position for oil sealing.
6. The oil circuit of claim 5, wherein the upstream end of said
eccentric oil feed line is in fluid communication with said first
fastener socket, and said boss has a cutaway section to permit flow
of oil from the housing oil feed line to the eccentric oil feed
line, said upstream end of said housing oil feed line being in
fluid communication with the oil supply, and said down stream end
of said housing oil feed line being in fluid communication with
said first fastener socket, said upstream end of said eccentric oil
feed line being in fluid communication with said first fastener
socket, and said down stream end of said eccentric oil feed line
being in fluid communication with said main bearings, wherein said
oil supply is in fluid communication with said first fastener
socket through said housing oil feed line, and said first fastener
socket is in fluid communication with said main bearings through
said eccentric oil feed line, thereby providing an oil supply
circuit for delivering oil from the oil supply to the main
bearings.
7. The oil circuit of claim 1, further having a first fastener
socket, wherein said oil circuit has a primary oil flow pathway
from said oil supply to said main bearings at all of said
compression ratio settings, said primary oil flow pathway including
a first pathway section from said oil supply to said first fastener
socket and a second pathway section from said fastener socket to
said main bearings, thereby providing a streamline flow passageway
with minimal pressure loss.
8. The oil circuit of claim 5, wherein the upstream end of said
eccentric oil feed line bypasses said first fastener socket.
9. The oil circuit of claim 2 wherein said oil seal is made out of
a compressive material for provide seating contact between said oil
seal and said housing.
10. The oil circuit of claim 2 further including a spring for
providing sealing contact between said oil seal and said
housing.
11. The oil circuit of claim 10 wherein said spring is located in
said first fastener socket for providing sealing contact between
said oil seat and said housing.
12. The oil circuit of claim 1, where in said first fastener access
cutout is located in said bearing cap.
13. The oil circuit of claim 1, further including eccentric support
outer bearings, and bleed holes for release of oil from the oil
supply circuit for lubricating the eccentric support outer
bearings.
14. The oil circuit of claim 12, wherein said bearing cap has a
parting surface and a normal imaginary plane, said normal imaginary
plane being normal to said parting surface, the rotational axis of
the crankshaft being entirely within said imaginary plane, said
bearing cap having a minor half located on one side of said normal
imaginary plane, and a major half located on the other side of said
normal imaginary plane, said major half of said bearing cap being
generally larger than said minor half of said bearing cap, wherein
said first fastener access cutout is located in said major half of
said bearing cap, for providing both a small eccentric support and
a first fastener access cutout long enough for an open oil circuit
at all compression ratio settings.
15. The oil circuit of claim 14, wherein said connecting rod
advances from the region adjacent to said minor half of said
bearing cap to the region adjacent to said major half of said
bearing cap, thereby providing a crankshaft rotational direction
yielding an eccentric support that is stiff and compact while also
having a first fastener access cutout and an eccentric oil feed
line drilled hole.
16. The oil circuit of claim 1 wherein said sealing means includes
a small curtain area circumference and a small assembly tolerance
between said housing and said outer bearing surface.
17. The oil circuit of claim 1, further having a first compression
ratio setting, a first fastener line of action and a first flow
stream segment, said flow stream segment being generally aligned
with said first fastener line of action at said first compression
ratio setting.
18. The oil circuit of claim 17, further including an oil seal for
substantively minimizing leakage of oil between the housing oil
feed line and the eccentric oil feed line, wherein said first flow
stream segment passes through said oil seal.
19. The oil circuit of claim 1, further having a first fastener
socket, wherein said eccentric oil feed line is connected to said
first fastener socket downstream of said first fastener access
cutout.
Description
[0001] This application relates to Provisional Application No.
60/849,314 having a filing date of Oct. 3, 2006.
BACKGROUND OF THE INVENTION
[0002] Variable compression ratio can significantly increase the
fuel efficiency of reciprocating piston engines used in passenger
cars and trucks. The present invention relates to variable
compression ratio mechanisms having a crankshaft mounted in
eccentric supports, and more specifically to the oil supply circuit
used to deliver oil to the main bearings of the crankshaft.
[0003] Kurt Imren Yapici shows a variable compression ratio engine
in U.S. Pat. No. 6,588,384 issued on Jul. 8, 2003 and assigned to
FEV GmbH of Germany. An oil galley that circumnavigates an
eccentric support can be seen in FIG. 7 of the patent. A crankshaft
main bearing for the engine is located in the eccentric support. An
engine similar in design was shown in Issue 22 of the FEV
publication Spectrum, dated February 2003. A similar oiling system
is also shown in U.S. Pat. No. 6,247,430 issued on Jun. 19, 2001 to
Yapici and also assigned to FEV. FIG. 3 of the patent shows an oil
feed passageway 20 in the engine housing that feeds a shallow
channel 17 in the eccentric disk segment 3.2. Oil then flows
through drilling 18 to the crankshaft main bearings 2. A stiff
eccentric carrier is necessary for providing reliable and robust
main bearing life. The oil flow passageway 18 weakens the bearing
cap and compromises stiffness. Oil leakage from the oil circuit is
believed to be a problem due to the large area through which oil
can leak. However, any further enlargement of the oil flow
passageway 18 to accommodate oil sealing means would further risk
the structural integrity of the bearing cap. Alternatively, oil
sealing means could be installed in the housing without
compromising the structure of the bearing cap. Referring again to
FIG. 7 of U.S. Pat. No. 6,588,384, the leaking oil is used to
lubricate the outer bearing surface of the eccentric support, with
a groove around the outer circumference of the eccentric support
being provided for distribution of the oil around the bearing
surface. In general variable compression ratio engines offer the
potential for significantly improving automobile fuel economy. Oil
leakage with these variable compression ratio engines will increase
oil pump power consumption, and increase aerodynamic drag and
windage on the crankshaft webs and other cranktrain components.
These losses have been accepted considering the larger gains that
can be realized with variable compression ratio, and the secondary
benefit of using the leakage oil for lubricating the eccentric
support's outer bearings.
[0004] Mendler (the current applicant) shows another variable
compression ratio engine in U.S. Pat. No. 6,443,107 issued on Sep.
3, 2002. FIG. 11 shows an oiling system similar to the FEV system.
Mendler shows another variable compression ratio engine in U.S.
Pat. No. 6,637,348 issued on Oct. 28, 2003. FIGS. 1 and 2 show a
fully enclosed oil circuit having no oil loss upstream of the main
bearings. The United States Department of Energy and Argonne
National Laboratory paid for construction of a prototype engine
similar to the design shown in U.S. Pat. No. 6,637,348. A report on
the engine by Charles Mendler and Roland Gravel was published by
SAE International circa Jun. 5, 2002. The engine has proven to be
highly robust, and is currently located at Oak Ridge National
Laboratory where it continues to be used for research. While the
enclosed sealing system is robust, the manufacturing and assembly
cost of the enclosed oiling system is a significant disadvantage of
the system. The eccentric carrier is also relatively large and
heavy.
[0005] Lawrence et al. show a variable compression ratio engine
having eccentric main bearing supports in US Patent Application
Publication No.: US 2006/0112911 A1, having a publication date of
Jun. 1, 2006. FIG. 3 show an oil feed passageway 46 in the engine
housing that feeds a shallow channel 48 in the eccentric disk
segment 26a. Oil then flows through drilling 42 to the crankshaft
main bearings 34. A report on the engine authored by Kevin Duffy
was published by SAE International Sep. 25, 2006 titled Update on
Diesel HCCI Activities at Caterpillar. The engine has been built
and tested. While fuel economy is important, the primary objective
for the Caterpillar engine is reduction of air pollutants using the
variable compression ratio to change and control the combustion
process. New federal regulations require engine manufacturers to
reduce emissions of nitrous oxides NOx and particulate matter PM.
The pictures of the engine in the report closely match FIG. 3 of
the patent. Channel 48 has an exceptionally long length, and it is
expected that a significant amount of oil will leak from the
system. Another problem with the oil circuit shown in FIG. 3 is
that it is not streamline. The sharp bends in the oil flow circuit
will require use of a higher oil feed pressure, which will result
both in increased oil leakage and need for a more power consuming
oil pump.
[0006] Accordingly, objectives of the present invention are to
provide an oil supply circuit for variable compression ratio
engines of the eccentric main bearing support type, that provides
minimal oil loss and low manufacture and assembly cost. Another
objective is to provide a streamline oil flow circuit in order to
minimize the oil pump power requirements. Another objective is to
provide an oil supply circuit and eccentric support design that is
compact and light in design, while also providing rigid support and
alignment of the crankshaft main bearings.
SUMMARY OF THE INVENTION
[0007] According to the present invention, a variable compression
ratio machine having main bearings mounted in an eccentric carrier
or support includes an oil seal located primarily in a main bearing
cap for minimizing leakage of pressurized main bearing oil. The
seal is located generally in a first main bearing fastener socket
or fastener access cutout in order to minimize structurally
compromising the bearing cap, and a portion of the fastener socket
preferably is used as an oil passageway as well as for wrench
access to the fastener. The oil seal and oil circuit of the present
invention enable the size of the eccentric support to be minimized
while also providing highly effective oil sealing. In more detail,
a significant advantage of the present invention is that highly
effective oil sealing is attained without compromising the size or
structural integrity of the bearing cap. A second significant
advantage of the present invention is that it can be manufactured
and assembled at low cost. The oil sealing system of the present
invention is robust and highly reliable.
[0008] In the preferred embodiment of the present invention the
seal includes a boss that nests into the fastener socket, thereby
providing a low cost means for retaining or holding the seal in
position.
[0009] Preferably the seal has a hole through the boss for
permitting the oil to flow into the lower portion of the fastener
socket. A short oil passageway or eccentric oil feed line is then
used to direct oil from the fastener socket to the main bearings.
The eccentric oil feed line is relatively short and results in an
acceptably small reduction of bearing cap stiffness.
[0010] The oil flow circuit is streamline and permits the oil feed
pressure to be minimized. The low feed pressure and the effective
sealing means according to the present invention enables oil pump
power to be minimized and engine efficiency maximized. The oil seal
is highly reliable and has a low manufacturing and assembly
cost.
BRIEF DESCRIPTION OF THE DRAWING
[0011] FIG. 1 is intended to illustrate a variable compression
ratio engine or machine having an oil seal according to the present
invention.
[0012] FIG. 2 is a partial cutaway view of a portion of FIG. 1.
[0013] FIG. 3 shows a detail view of the sealing element.
[0014] FIG. 4 shows a second view of the sealing element.
[0015] FIG. 5 is similar to FIG. 2, but shows an alternate location
for the internal oil flow passageway.
[0016] FIG. 6 is intended to illustrate a bearing cap having an
alternate fastener cutout shape and an alternate seal shape.
[0017] FIG. 7 is intended to illustrate the present invention with
the oil sealing element located in the housing.
[0018] FIG. 8 is intended to illustrate the present invention in an
eccentric support having a vertical bearing cap.
[0019] FIG. 9 is intended to illustrate a sealing element with an
oil bleed groove.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] FIGS. 1 and 2 are partial section views that are intended to
schematically illustrate the preferred embodiment of the present
invention. FIGS. 1 and 2 show an oil circuit for a variable
compression ratio mechanism 1 having an oil supply 2, a housing 4
and at least one cylinder 6 mounted in the housing, a piston 8
mounted for reciprocating movement in the cylinder, a crankshaft 10
defining an axis about which the crankshaft rotates 12, and a
connecting rod 14 connecting the piston to the crankshaft. The
variable compression ratio mechanism further has at least one
eccentric support 16 for supporting the crankshaft about the
rotational axis of the crankshaft 12. The eccentric support is
mounted in the housing for pivoting relative to the housing about a
pivot axis 18. The pivot axis is substantially parallel to and
spaced from the rotational axis of the crankshaft. Main bearings 20
are mounted in the eccentric support for supporting the crankshaft.
The variable compression ratio mechanism may be used in an engine
or in other applications where a variable compression ratio is
useful. The variable compression ratio mechanism has a range of
compression ratio settings, the range including at least a maximum
compression ratio setting and a minimum compression ratio
setting.
[0021] The eccentric support includes a bearing cap 22 and a
plurality of fasteners 24 for retaining the crankshaft in the
eccentric support.
[0022] According to the present invention, the eccentric support
further includes a first fastener access cutout 26. According to
the preferred embodiment of the present invention, eccentric
support 16 also includes an oil seal 28 located primarily in the
region of the first access cutout 26.
[0023] Bearing cap 22 further including a bearing socket 30 for
retaining one or more of the main bearings 20 in eccentric support
16.
[0024] Housing 4 includes at least one housing oil feed line 32.
Housing oil feed line 32 has an upstream end 34, the upstream end
being in fluid communication with oil supply 2, and a down stream
end 36, the down stream end being in fluid communication with first
fastener access cutout 26.
[0025] Referring now to FIGS. 1, 2 and 3, eccentric support 16
includes an eccentric oil feed line 38. Eccentric oil feed line 38
has an upstream end 40, the upstream end being connected to the
first fastener access cutout 26, and a down stream end 42, the down
stream end being in fluid communication with main bearings 20.
[0026] Arrow 44, including upper and lower arrow segments, is
intended to illustrate the primary oil flow pathway of the bearing
oil. Primary oil flow pathway 44 extends from oil supply 2 to main
bearings 20. Primary oil flow pathway 44 including a first pathway
section 45 extending from oil supply 2 to first fastener access
cutout 26, and a second pathway section 47 extending from first
fastener access cutout 26 to main bearings 20. According to the
preferred embodiment of the present invention, the oil primarily
flows directly out of the first pathway section 45 into the second
pathway section 47, with the junction of the two pathways being
located within the first fastener access cutout.
[0027] Eccentric support 16 has an outer bearing surface 46 having
an outer circumference 48 for pivotably supporting eccentric
support 16 in housing 4. A small clearance gap 49 separates bearing
surface 46 from housing 4.
[0028] According to the present invention, the oil circuit further
has a sealing curtain area 43 around first fastener access cutout
26. The preferred embodiment of the present invention includes
sealing means for providing a small sealing curtain area 43 through
which oil can leak from the oil flow pathway 44. In more detail,
the present invention includes sealing means for minimizing oil
leakage between the housing oil feed line 32 and eccentric oil feed
line 38. The sealing curtain area 43 is generally the product of
the average or approximate radial clearance gap 49 between the
eccentric outer bearing surface including the sealing means and the
housing 4 around curtain 43, and the minimum perimeter length
around oil flow pathway 44 at the interface of the outer bearing
surface 46 and housing 4. In more detail sealing curtain area 43 is
generally the smallest imaginary surface that if it was
impermeable, would seal the clearance gap between the housing oil
feed line 32 and the eccentric oil feed line 38 and stop oil
leakage. In the preferred embodiment of the present invention, oil
seal 28 forms a seal with housing 4 for minimizing the oil sealing
curtain area 43, and thereby minimizing oil leakage. With respect
to location of oil seal 28, the sealing function is preferably
primarily located in or generally in the first fastener access
cutout in order to minimize the length of the sealed perimeter and
in turn minimize curtain area. Preferably oil seal 28 is located in
first fastener access cutout 26, although the sealing means may
extend outside of first fastener cutout 26 in some embodiments of
the present invention.
[0029] According to the present invention, oil supply 2 is in fluid
communication with first fastener access cutout 26 through housing
oil feed line 32, and first fastener access cutout 26 is in fluid
communication with main bearings 20 through eccentric oil feed line
38, thereby providing an oil supply circuit for delivering oil from
oil supply 2 to the main bearings 20 with minimal oil leakage.
[0030] Preferably, according to the present invention, the
downstream end of the housing oil feed line 36 is directly or
almost directly aligned with first fastener access cutout 26 at all
compression ratio settings, to provide streamlined flow of oil from
the first pathway section 45 into the second pathway section 47,
for reducing the required oil pressure of the lubrication
system.
[0031] Bearing cap 22 has a first fastener 50, and first fastener
50 has a first fastener line of action 52. First fastener 50 has a
first fastener head 54 having an approximate first fastener head
circumference 56. Those skilled in the art will appreciate that
various types of fastener heads may be used according to the
present invention. First fastener head circumference 56 and line of
action 52 define an imaginary cylinder 58. According to the
preferred embodiment of the present invention, first fastener
access cutout 26 includes at least the region inside imaginary
cylinder 58 and inside outer circumference 48 that can be occupied
with oil that is freely in fluid communication with main bearings
20. In embodiments of the present invention including a seal such
as oil seal 28, first fastener access cutout 26 also refers to the
region inside seal 28. In the preferred embodiment of the present
invention, first fastener access cutout 26 extends slightly outside
27 of imaginary cylinder 58. According to the preferred embodiment
of the present invention, the oil circuit passes through first
fastener access cutout 26, and in more detail eccentric oil feed
line 38 and second pathway 47 do not bypass first fastener access
cutout 26.
[0032] Referring now to FIGS. 2 and 5, preferably according to the
present invention the fastener access cutout 26 includes retaining
means for retaining the oil seal in location. Eccentric support 16
may optionally include a first fastener socket 60 or 60B.
Optionally the access cutout may be the first fastener socket. FIG.
7 shows a first fastener access cutout that is simply the first
fastener socket. Preferably first fastener socket 60 is slightly
larger in diameter than imaginary cylinder 58 to provide access for
assembly and wrench access. First fastener 50 may be a hex head
bolt, a 12 point bolt (shown), a socket head bolt, or another
functional type of fastener. In the preferred embodiment of the
present invention, oil seal 28 or 28B further includes a boss 62 or
62B. Preferably boss 62 or 62B is positioned in first fastener
socket 60 or 60B for retaining oil seal 28 or 28B in position for
oil sealing.
[0033] Referring now to FIG. 2, preferably eccentric oil feed line
38 is connected to first fastener socket 60 downstream of said
first fastener access cutout 26.
[0034] Oil seal 28 is intended to substantively minimizing leakage
of oil between housing oil feed line 32 and eccentric oil feed line
38. Those skilled in the art will appreciate that various types and
shapes of sealing means can be used according to the present
invention. FIGS. 1 through 4 show oil seal 28. Referring now to
FIG. 5, eccentric oil feed line 38B bypasses first fastener socket
60B. Oil seal 28B is similar to oil seal 28, but accommodates
eccentric oil feed line 38B. Referring now to FIG. 6, oil seal 28C
has an alternate shape. Referring now to FIG. 7, an optional
housing oil seal 29 is located in housing 4. Sealing means may be
provided in some embodiments of the present invention by minimizing
perimeter length around oil flow pathway 44 at the interface of the
outer bearing surface 46 and housing 4, and by employing small
assembly tolerances to minimizing the radial clearance gap between
the eccentric outer bearing surface 46 and the housing 4 and
thereby provide an acceptably small sealing curtain area.
Preferably a removable oil seal is used such as oil seal 28,
however, some embodiments of the present invention may be practiced
without a removable sealing element, and in more detail where the
sealing means includes small mechanical tolerances to provide a
small radial clearance gap, and a short perimeter length to provide
a small oil sealing curtain area.
[0035] Referring now to FIGS. 2-4, preferably the upstream end of
said eccentric oil feed line 38 is in fluid communication with
first fastener socket 60, and boss 62 has a cutaway section or hole
64 to permit flow of oil from the housing oil feed line 32 to the
eccentric oil feed line 38. The upstream end of housing oil feed
line 34 is in fluid communication with oil supply 2, and the down
stream end of housing oil feed line 36 is in fluid communication
with first fastener socket 60. The upstream end of eccentric oil
feed line 38 is in fluid communication with first fastener socket
60, and the down stream end of eccentric oil feed line 42 is in
fluid communication with main bearings 20. Accordingly, oil supply
2 is in fluid communication with first fastener socket 60 through
housing oil feed line 32, and first fastener socket 60 is in fluid
communication with main bearings 20 through eccentric oil feed line
38, thereby providing an oil supply circuit for delivering oil from
the oil supply 2 to the main bearings 20.
[0036] In the embodiment of the present invention shown in FIG. 2,
the primary oil flow pathway 44 from oil supply 2 to main bearings
20 is open at all of said compression ratio settings. In more
detail, primary oil flow pathway 44 including a first pathway
section 45 from oil supply 2 to imaginary cylinder 58 into first
fastener socket 60 and a second pathway section from first fastener
socket 60 through eccentric oil feed line 38 to main bearings 20
that is streamline and open at all compression ratio settings,
thereby providing a streamline flow passageway with minimal
pressure loss.
[0037] Referring now to FIGS. 1 and 2, variable compression ratio
mechanism 1 has a plurality of compression ratio settings including
a first compression ratio setting 66. Flow pathway 44 also includes
a first flow segment 68 at first compression ratio setting 66.
According to an embodiment of the present invention, first flow
stream segment 68 and first fastener line of action 52 are
generally aligned at first compression ratio setting 66, thereby
providing a streamlined flow path. Preferably first flow segment 68
passes through oil seal 28.
[0038] FIG. 5 shows a blocked first fastener socket 60B. In the
embodiment of the present invention illustrated in FIG. 5, first
fastener socket 60B is not considered part of first fastener access
cutout 26 because oil cannot flow freely to main bearings 20
through first fastener socket 60B. According to the present
invention, the upstream end of eccentric oil feed line 38B may
optionally bypasses first fastener socket 60B. As mentioned
previously, in the preferred embodiment of the present invention,
first fastener access cutout 26 extends slightly outside 27 of
imaginary cylinder 58, as depicted in FIGS. 2 and 5. According to
the preferred embodiment of the present invention, the oil circuit
passes through first fastener access cutout 26, and in more detail
eccentric oil feed line 38 or 38B does not bypass first fastener
access cutout 26. As shown in FIG. 5, eccentric oil feed line 38B
may optionally bypass first fastener socket 60B, while being in
fluid communication with first fastener cutout 26 according to the
present invention.
[0039] Referring now to FIGS. 1 through 4, preferably, according to
the present invention oil seal 28 is made out of an elastic or
compressive material to provide sealing contact between the oil
seal and housing 4. Oil seal 28 may be formed out of PTFE or
another functional material. Oil seal 28 may additionally be made
out of a composition of materials, such as a metal backed seal
having a PTFE sliding surface.
[0040] Referring now to FIG. 5, a spring 70 may be used to bias oil
seal 28B into contact with housing 4 for providing a sealing
contact. If used, preferably spring 70 is located in first fastener
socket 60B.
[0041] Referring now to FIGS. 1, 2, 5 and 6, preferably first
fastener access cutout 26 is located in bearing cap 22. Referring
now to FIG. 8, optionally first fastener access cutout 26D is
located in the primary support structure 76 of the eccentric
support 16B.
[0042] Referring now to FIGS. 2 and 9, eccentric support 16 has one
or more eccentric support outer bearings 46 that ride on a suitably
formed mating surface in housing 4. Referring now to FIG. 9, oil
seal 28E may include bleed holes or grooves 74 for release of oil
from the oil supply circuit for lubricating the eccentric support
outer bearings 46.
[0043] Referring again to FIG. 1, bearing cap 22 has a parting
surface 78 and a normal imaginary plane 80. The normal imaginary
plane is normal to parting surface 78, and the rotational axis of
the crankshaft 12 lies entirely within imaginary plane 80. Bearing
cap 22 has a minor half 82 located on one side of said normal
imaginary plane, and a major half 84 located on the other side of
said normal imaginary plane, where the major half of the bearing
cap is generally larger than the minor half of the bearing cap.
Preferably, according to the present invention, first fastener
access cutout 26 is located in the major half 84 of bearing cap 22,
for providing a small diameter eccentric 16 having a first fastener
access cutout 26 long enough for an open oil circuit at all
compression ratio settings.
[0044] Preferably according to the present invention, connecting
rod 14 advances from the region adjacent to minor half 82 of
bearing cap 22 to the region adjacent to major half 84 of said
bearing cap 22, thereby providing a crankshaft rotational direction
yielding an eccentric support that is stiff and compact while also
having a first fastener access cutout and an eccentric oil feed
line drilled hole that can weaken the part due to removed metal.
According to the preferred embodiment of the present invention, the
downstream end 42 of flow pathway 47 introduces oil to the
crankshaft main bearings 20 slightly after piston 8 reaches its
highest location in cylinder 6, thereby providing optimum
lubrication of main bearings 20 and crankshaft 10.
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