US20100006057A1

US20100006057A1 - Oil seal

Info

Publication number: US20100006057A1
Application number: US12/311,561
Authority: US
Inventors: Edward Charles Mendler
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-10-03
Filing date: 2007-09-25
Publication date: 2010-01-14
Also published as: WO2008042154A3; GB2456941B; WO2008042154A2; GB0907293D0; GB2456941A

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.

Description

This application relates to Provisional Application No. 60/849,314 having a filing date of Oct. 3, 2006.

BACKGROUND OF THE INVENTION

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.
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.
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.
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 26 a. 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.
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

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.
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.
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.
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

FIG. 1 is intended to illustrate a variable compression ratio engine or machine having an oil seal according to the present invention.

FIG. 2 is a partial cutaway view of a portion of FIG. 1.

FIG. 3 shows a detail view of the sealing element.

FIG. 4 shows a second view of the sealing element.

FIG. 5 is similar to FIG. 2, but shows an alternate location for the internal oil flow passageway.

FIG. 6 is intended to illustrate a bearing cap having an alternate fastener cutout shape and an alternate seal shape.

FIG. 7 is intended to illustrate the present invention with the oil sealing element located in the housing.

FIG. 8 is intended to illustrate the present invention in an eccentric support having a vertical bearing cap.

FIG. 9 is intended to illustrate a sealing element with an oil bleed groove.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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.
The eccentric support includes a bearing cap 22 and a plurality of fasteners 24 for retaining the crankshaft in the eccentric support.
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.
Bearing cap 22 further including a bearing socket 30 for retaining one or more of the main bearings 20 in eccentric support 16.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.

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.