US20170184198A1 - Oil ring - Google Patents

Oil ring Download PDF

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Publication number
US20170184198A1
US20170184198A1 US15/334,362 US201615334362A US2017184198A1 US 20170184198 A1 US20170184198 A1 US 20170184198A1 US 201615334362 A US201615334362 A US 201615334362A US 2017184198 A1 US2017184198 A1 US 2017184198A1
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United States
Prior art keywords
side rail
degrees
oil ring
outer peripheral
upper side
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
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US15/334,362
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English (en)
Inventor
Naokazu Kawase
Hajime Nakagawa
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Honda Motor Co Ltd
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Honda Motor Co Ltd
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Filing date
Publication date
Application filed by Honda Motor Co Ltd filed Critical Honda Motor Co Ltd
Assigned to HONDA MOTOR CO., LTD. reassignment HONDA MOTOR CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KAWASE, NAOKAZU, NAKAGAWA, HAJIME
Publication of US20170184198A1 publication Critical patent/US20170184198A1/en
Priority to US15/725,786 priority Critical patent/US9915345B2/en
Abandoned legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
    • F16J9/06—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction using separate springs or elastic elements expanding the rings; Springs therefor ; Expansion by wedging
    • F16J9/064—Rings with a flat annular side rail
    • F16J9/066—Spring expander from sheet metal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
    • F16J9/12—Details
    • F16J9/20—Rings with special cross-section; Oil-scraping rings
    • F16J9/206—One-piece oil-scraping rings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
    • F16J9/12—Details
    • F16J9/20—Rings with special cross-section; Oil-scraping rings
    • F16J9/203—Oil-scraping rings

Definitions

  • the present invention relates to an oil ring for a piston of a reciprocating machine such as an internal combustion engine, and in particular to a composite oil ring including a pair of side rails and an expander interposed between the two side rails.
  • the oil ring used in the pistons of conventional reciprocating internal combustions typically consists of a three piece oil ring including a pair of annular side rails positioned one above the other and a space expander interposed between the two side rails. See JP2003-194222A, for instance.
  • a primary object of the present invention is to provide an oil ring that can minimize the frictional resistance without impairing the oil control function such as the scraping of lubricating oil from the cylinder wall surface by the oil ring.
  • an oil ring ( 13 ) configured to be received in an oil ring groove ( 8 ) formed in an outer circumferential surface of a piston ( 4 ), comprising an upper side rail ( 16 ) and a lower side rail ( 17 ) each consisting of an annular plate member; and an annular expander ( 18 ) interposed between the upper side rail and the lower side rail such that the upper side rail, the lower side rail and the expander are disposed in a coaxial relationship; wherein an outer peripheral surface ( 16 E) of the upper side rail includes a slanted surface with a radially inward slant (such that an upper part thereof recedes more radially inward than a lower part thereof) slanting by a first slant angle ( ⁇ 1 ) with respect to an axial line of the piston; and wherein an outer peripheral surface of the lower side rail includes a slanted surface with a radially inward slant (such that an upper part thereof recedes more radially inward than
  • each side rail is subjected to a lift that moves the side rail away from the cylinder wall surface owing to a relatively thick buildup of lubricating oil between the outer peripheral surface of the side rail and the cylinder wall surface.
  • the lubricating oil is not excessively scraped off the cylinder wall by the oil ring, and hence the shear resistance of the lubricating oil can be reduced.
  • the lubricating oil is scraped off the cylinder wall surface in an effective manner and the thickness of the oil film is appropriately controlled.
  • the upper side rail tilts radially outward (the inner peripheral part thereof is raised in comparison with the outer peripheral part thereof). Therefore, during the upward stroke of the piston, the effective slant angle of the outer peripheral surface is reduced from the first slant angle by this tilting action.
  • both the upper and lower side rails are allowed to engage the cylinder wall surface with an optimum slant angle which may be approximately equal to the second slant angle.
  • a clearance ( 20 ) is defined between an upper wall surface of the oil ring groove and the upper end surface of the upper side rail such that the upper side rail can tilt in a radially outward direction by a prescribed tilt angle during an upward stroke of the piston.
  • the tilt angle that is caused during the upward stroke of the piston can be accurately controlled by determining the size of the clearance and the resiliency of the expander.
  • the first slant angle is greater than the tilt angle preferably by 0.5 degrees to 4.5 degrees, and more preferably by 1.0 degree to 3.0 degrees.
  • the first slant angle is between 2.5 degrees and 10.5 degrees, and more preferably between 4.0 degrees and 7.5 degrees.
  • the second slant angle is preferably between 0.5 degrees and 4.5 degrees, and more preferably between 1.0 degree and 3.0 degrees.
  • the tilt angle is preferably between 2.0 degrees and 6.0 degrees.
  • the outer peripheral surface of the upper side rail is connected to a lower end surface thereof via a smooth curve ( 16 G), and the outer peripheral surface of the lower side rail is connected to a lower end surface thereof via a smooth curve ( 17 G).
  • the outer peripheral surface of the upper side rail is provided with a barrel shape having a vertically intermediate part thereof bulging radially outward
  • the outer peripheral surface of the lower side rail is provided with a barrel shape having a vertically intermediate part thereof bulging radially outward
  • An oil ring configured as discussed above can minimize frictional resistance without impairing the function to control the oil film thickness.
  • FIG. 1 is a sectional view of a piston fitted with an oil ring embodying the present invention
  • FIG. 2 is a cross sectional view of the oil ring
  • FIG. 3 a is an enlarged cross sectional view of an upper side rail of the oil ring with different lateral and vertical magnification factors (the lateral dimension being five times more enlarged than the vertical dimension);
  • FIG. 3 b is an enlarged cross section view of a lower side rail of the oil ring with different lateral and vertical magnification factors (the lateral dimension being five times more enlarged than the vertical dimension);
  • FIG. 4 is a view similar to FIG. 2 showing the state of the oil ring when the piston is moving upward;
  • FIG. 5 is a view similar to FIG. 2 showing the state of the oil ring when the piston is moving downward;
  • FIG. 6 a is a diagram illustrating a planar pad moving over a planar surface at a speed U;
  • FIG. 6 b is a graph showing the relationship between the load bearing capacity and a parameter m representing the angle of the planar pad relative to the planar surface;
  • FIG. 7 is a graph showing the relationship between the friction force and the angle between the outer peripheral surface of the lower rail and the cylinder wall surface for two different oil film thicknesses.
  • FIG. 8 is a graph comparing the lubricating consumptions of the present invention and the prior art.
  • a cylinder block 2 of an internal combustion engine 1 is provided with a cylinder 3 having a circular cross section and extending along a prescribed axial line (which is assumed to be extending vertically for the convenience of description), and a piston 4 is slidably received in the cylinder 3 .
  • a combustion chamber is defined by an upper part of the cylinder 3 , the top surface of the piston 4 and a cylinder head not shown in the drawing.
  • the outer peripheral part of the piston 4 is formed with a first ring groove 6 , a second ring groove 7 and a third ring groove 8 , in that order from the top.
  • Each of these ring grooves is annular in shape.
  • the first ring groove 6 and the second ring groove 7 receive a first pressure ring 11 and a second pressure ring 12 , respectively, and the third ring groove 8 receives an oil ring 13 .
  • the third ring groove 8 includes a bottom surface 8 A defined by a circumferential surface centered around the axial line of the piston 4 and having a prescribed vertical width (in the axial direction of the piston 4 ), an annular upper wall surface 8 B extending radially outward from the upper edge of the bottom surface 8 A and an annular lower wall surface 8 C extending radially outward from the lower edge of the bottom surface 8 A.
  • the upper wall surface 8 B and the lower wall surface 8 C are both defined by planes that are perpendicular to the axial line of the piston 4 .
  • the third ring groove 8 has a rectangular cross section.
  • An oil ejection passage 14 extends from the corner part defined between the lower wall surface 8 C and the bottom surface 8 A of the third ring groove 8 to the back or inner side of the piston 4 .
  • the internal combustion engine 1 consists of an automotive engine.
  • the diameter of the cylinder 3 may be in the range of 68 mm to 92 mm, and the stroke of the piston 4 may be in the range of 60 mm to 100 mm.
  • the oil ring 13 consists of a three-piece oil ring including an upper side rail 16 , a lower side rail 17 and an expander (space expander) 18 interposed between the upper side rail and the lower side rail 17 .
  • the expander 18 includes an annular expander main body 18 A which is made of sheet metal, and is provided with a wavy shape as it extends along the circumferential direction.
  • the main body is provided with a circumferential end gap therein.
  • the wavy shape of the expander main body 18 A is thus defined by upper projecting parts 18 B and lower projecting parts 18 C created by bending the sheet metal material of the expander main body 18 A in an alternating manner along the circumferential direction.
  • Each upper projecting part 18 B is provided with an upper ear portion 18 D projecting upward from a radially inner part of the upper surface thereof, and each lower projecting part 18 C is provided with a lower ear portion 18 E projecting downward from a radially inner part of the lower surface thereof.
  • the upper ear portions 18 D jointly define a radially outwardly facing shoulder surface forming an obtuse angle with respect to the upper surface of the upper projecting parts 18 B
  • the lower ear portions 18 E jointly define a radially outwardly facing shoulder surface forming an obtuse angle with respect to the lower surface of the lower projecting parts 18 C.
  • the side rails 16 and 17 are generally planar annular members each defining an upper end surface 16 A, 17 A and a lower end surface 16 B, 17 B that are in parallel to each other, and an outer peripheral surface 16 C, 17 C and an inner peripheral surface 16 D, 17 D which are concentric to each other.
  • FIG. 3 a is an enlarged cross sectional view of an outer peripheral part of the upper side rail 16 of the oil ring 13
  • FIG. 3 b is an enlarged cross sectional view of an outer peripheral part of the lower side rail 17 of the oil ring 13
  • the lateral and vertical dimensions are enlarged with different magnification factors; i.e., the lateral dimension is five times more enlarged than the vertical dimension.
  • each major outer peripheral surface 16 E, 17 E which is located in a vertically intermediate part of the outer peripheral surface of the corresponding side rail 16 , 17 is slanted with respect to the axial line in a radially inward direction or in such manner that the upper part of the major outer peripheral surface 16 E, 17 E recedes away from the opposing cylinder wall surface or toward the central axial line of the cylinder 3 in comparison with the lower part of the major outer peripheral surface 16 E, 17 E.
  • each major outer peripheral surface 16 E, 17 E defines the outer peripheral surface of a cone with an upward taper.
  • the slant angle of the major outer peripheral surface 16 E of the upper side rail 16 is defined as a first slant angle ⁇ 1
  • the slant angle of the major outer peripheral surface 17 E of the lower side rail 17 is defined as a second slant angle ⁇ 2
  • the outer peripheral surface 16 C, 17 C of each of the side rails 16 and 17 may be defined as a true conical surface or a conical surface with a barrel shaped bulge (where a vertically middle part protrudes radially outward as compared to an outer peripheral surface of a true cone as is the case with the illustrated embodiment).
  • the first slant angle ⁇ 1 and the second slant angle ⁇ 2 may also be considered as the average values of the slant angles of various parts of the outer peripheral surfaces of the respective side rails 16 and 17 .
  • an upper outer peripheral surface 16 F, 17 F is defined as a curve (in the cross sectional view) that smoothly connects the corresponding major outer peripheral surface 16 E, 17 E with the corresponding upper end surface 16 A, 17 A.
  • a lower outer peripheral surface 16 G, 17 G is defined as a curve (in the cross sectional view) that smoothly connects the corresponding major outer peripheral surface 16 E, 17 E with the corresponding lower end surface 16 B, 17 B.
  • each side rail 16 , 17 the major outer peripheral surface 16 E, 17 E accounts for a much larger part of the outer peripheral surface 16 C, 17 C than the corresponding upper outer peripheral surface 16 F, 17 F and/or the corresponding lower outer peripheral surface 16 G, 17 G.
  • Each upper outer peripheral surface 16 F, 17 F has a greater radius of curvature (in the cross sectional view of FIGS. 3 a and 3 b ) than the corresponding lower outer peripheral surface 16 G, 17 G. If each major outer peripheral surface 16 E, 17 E is barrel shaped, and is hence provided with a radius of curvature, this radius of curvature is greater than that of the corresponding upper outer peripheral surface 16 F, 17 F.
  • the upper side rail 16 and the lower side rail 17 are shaped identically except for the different configurations of the outer peripheral surfaces 16 C and 17 C thereof.
  • the upper side rail 16 , the lower side rail 17 and the expander 18 are combined in a mutually coaxial relationship.
  • the lower end surface 16 B of the upper side rail 16 abuts the upper ends of the upper projecting parts 18 B, and the inner peripheral surface 16 D of the upper side rail 16 abuts the radially outward facing sides of the upper ear portions 18 D.
  • the upper end surface 17 A of the lower side rail 17 abuts the lower ends of the lower projecting parts 18 C, and the inner peripheral surface 17 D of the lower side rail 17 abuts the radially outward facing sides of the lower ear portions 18 E.
  • the upper end surfaces 16 A and 17 A of the upper side rail 16 and the lower side rail 17 are substantially parallel to each other, and the vertical dimension (the distance between the upper end surface 16 A of the upper side rail 16 and the lower end surface 17 B of the lower side rail 17 ) of the oil ring 13 is at a minimum value.
  • the upper end surfaces 16 A and 17 A of the upper side rail 16 and the lower side rail 17 are provided with a radially outward slant and a radially inward slant, respectively.
  • a vertical clearance 20 which is present between the oil ring 13 and the third ring groove 8 as will be discussed hereinafter is thus taken up equally by the tilting of the upper side rail 16 and the lower side rail 17 in the opposite directions in the initial condition of the oil ring 13 .
  • the oil ring 13 is fitted into the third ring groove 8 such that the upper end surface 16 A of the upper side rail 16 opposes the upper wall surface 8 B, and the lower end surface 17 B of the lower side rail 17 opposes the lower wall surface 8 C.
  • the expander 18 is pre-stressed in a direction to expand in the radially outward direction so that the upper ear portions 18 D press the inner peripheral surface 16 D of the upper side rail 16 in the radially outward direction, and the lower ear portions 18 E press the inner peripheral surface 17 D of the lower side rail 17 in the radially outward direction. In other words, the expander 18 urges both the upper side rail 16 and the lower side rail 17 in the radially outward direction.
  • each side rail 16 , 17 is enabled to tilt in such a manner that the outer peripheral part thereof is higher or lower than the inner peripheral part thereof. Even if the upper side rail 16 and the lower side rail 17 are tilted in the radially outward direction in the initial condition, and the clearance 20 may not be apparent, the following description applies substantially equally.
  • the expander 18 is pushed downward by the upper side rail 16 so that the lower projecting parts 18 C are brought into contact with the upper end surface 17 A of the lower side rail 17 .
  • the upper side rail 16 is caused to tilt radially outward such that the outer peripheral part thereof is lower than the inner peripheral part thereof owing to the presence of the clearance 20 between the upper wall surface 8 B and the upper end surface 16 A of the upper side rail 16 .
  • the angle defined between the upper end surface 16 A of the upper side rail 16 and a plane perpendicular to the axial line of the cylinder 3 (piston 4 ) at this time is defined as a first tilt angle ⁇ 3 .
  • the expander 18 is pushed upward by the lower side rail 17 so that the upper projecting parts 18 B are brought into contact with the lower end surface 16 B of the upper side rail 16 .
  • the lower side rail 17 is caused to tilt such that the outer peripheral part thereof is higher than the inner peripheral part thereof owing to the presence of the clearance 20 between the lower wall surface 8 C and the lower end surface 17 B of the lower side rail 17 .
  • the angle defined between the lower end surface 17 B of the lower side rail 17 and a plane perpendicular to the axial line of the cylinder 3 (piston 4 ) at this time is defined as a second tilt angle ⁇ 4 .
  • the first tilt angle ⁇ 3 and the second tilt angle ⁇ 4 can be selected freely, and may be between 2.0 degrees and 6.0 degrees, for instance. More preferably, the first tilt angle ⁇ 3 and the second tilt angle ⁇ 4 may be between 2.0 degrees and 4.0 degrees.
  • the first tilt angle ⁇ 3 and the second tilt angle ⁇ 4 can be adjusted by selecting the vertical dimensions of the upper side rail 16 , the lower side rail 17 and/or the expander 18 for the given vertical dimension of the third ring groove 8 , and/or the flexibility of the expander 18 .
  • the first tilt angle ⁇ 3 and the second tilt angle ⁇ 4 may be equal to each other, or may differ from each other. In the illustrated embodiment, the first tilt angle ⁇ 3 and the second tilt angle ⁇ 4 are both 2.5 degrees.
  • the first slant angle ⁇ 1 may be greater than the second slant angle ⁇ 2 (Condition 1).
  • the first slant angle ⁇ 1 may be greater than the first tilt angle ⁇ 3 (Condition 2).
  • the first slant angle ⁇ 1 may be preferably greater than the first tilt angle ⁇ 3 by an angle between 0.5 degrees and 4.5 degrees (Condition 3). More preferably, the first slant angle ⁇ 1 may be greater than the first tilt angle ⁇ 3 by an angle between 1.0 degree and 3.0 degrees.
  • the first slant angle ⁇ 1 is between 2.5 degrees and 10.5 degrees (Condition 4)
  • the second slant angle ⁇ 2 is between 0.5 degrees and 4.5 degrees (Condition 5). More preferably, the first slant angle ⁇ 1 may be between 4.0 degrees and 7.5 degrees, and the second slant angle ⁇ 2 may be between 1.0 degree and 3.0 degrees.
  • the load bearing capacity coefficient Kw for an infinite plane pad having a width D and moving at a relative velocity of U can be expressed by the following equation.
  • hi is the thickness of the oil film at the inlet of the pad
  • ho is the thickness (minimum oil film thickness) of the oil film at the outlet of the pad as shown in FIG. 6 a .
  • the load bearing capacity coefficient Kw represents the wedge effect (lift) for a unit surface area, and is known to take a maximum value when m is about 2.2 and decrease in value with an increase in the slant angle of the pad as shown in FIG. 6 b .
  • the angle between the main part of the outer peripheral surface 16 C, 17 C of each of the upper and lower side rails 16 and 17 and the wall surface 3 A of the cylinder 3 during the upward stroke of the piston 4 is preferably 0.5 degrees or more.
  • a margin of 0.5 degrees may be allowed for the optimum angle of 0.4 degrees so that the angle between the main part of the outer peripheral surface 16 C, 17 C of each of the upper and lower side rails 16 and 17 and the wall surface 3 A of the cylinder 3 during the upward stroke of the piston 4 may be preferably 1.0 degree or greater.
  • m is desired to be less than 15 to increase the lift owing to the wedge effect.
  • the vertical dimension (thickness) of each side rail 16 , 17 is 500 ⁇ m, and ho in the normal rpm range of the internal combustion engine 1 is 3 ⁇ m, m is 15 when the slant angle is about 4.8 degrees. Therefore, the angle between the main part of the outer peripheral surface 16 C, 17 C of each of the upper and lower side rails 16 and 17 and the wall surface 3 A of the cylinder 3 during the upward stroke of the piston 4 is preferably 4.5 degrees or less.
  • the angle between the main part of the outer peripheral surface 16 C, 17 C of each of the upper and lower side rails 16 and 17 and the wall surface 3 A of the cylinder 3 during the upward stroke of the piston 4 is preferably 3.0 degrees or less.
  • the upper side rail 16 tilts by the first tilt angle ⁇ 3 during the upward stroke of the piston 4 .
  • the major outer peripheral surface 16 E of the upper side rail 16 is slanted with respect to the wall surface 3 A of the cylinder 3 such that a lift owing to the wedge effect is applied to the upper side rail 16 .
  • the angle between the major outer peripheral surface 16 E of the upper side rail 16 and the wall surface 3 A of the cylinder 3 during the upward stroke of the piston 4 will be between 0.5 degrees and 4.5 degrees so that the upper side rail 16 receives a relatively large lift directed in the radially inward direction owing to the wedge effect.
  • the first slant angle ⁇ 1 is between 6.5 degrees and 10.5 degrees, and the tilt angle is 6.0 degrees, the angle between the major outer peripheral surface 16 E of the upper side rail 16 and the wall surface 3 A of the cylinder 3 during the upward stroke of the piston 4 will be between 0.5 degrees and 4.5 degrees.
  • the angle between the major outer peripheral surface 17 E of the lower side rail 17 and the wall surface 3 A of the cylinder 3 during the upward stroke of the piston 4 will be between 0.5 degrees and 4.5 degrees so that the lower side rail 17 receives a relatively large lift directed in the radially inward direction owing to the wedge effect.
  • the angle between the major outer peripheral surface 17 E of the lower side rail 17 and the wall surface 3 A of the cylinder 3 during the upward stroke of the piston 4 will be between 1.0 degree and 3.0 degrees.
  • each side rail 16 , 17 during the downward stroke of the piston 4 is small, and the distance between the side rail 16 , 17 and the wall surface 3 A of the cylinder 3 is kept small so that the lubricating oil on the wall surface 3 A of the cylinder 3 is effectively scraped off, and a prescribed thickness of lubricating oil is maintained on the wall surface 3 A of the cylinder 3 .
  • FIG. 7 is a graph showing the frictional force associated with the lower side rail 17 and the minimum oil film thickness ho (the oil film thickness at the lower end (outlet) of the major outer peripheral surface 17 E of the lower side rail 17 ) during the upward stroke of the piston 4 in relation with changes in the second slant angle ⁇ 2 of the lower side rail 17 .
  • This graph was obtained by experimental tests conducted under the condition where the diameter of the cylinder 3 is 73 mm, the stroke of the piston 4 is 78.7 mm, the tension of the oil ring 13 is 14.5 N, and the vertical dimension of the lower side rail 17 is 500
  • the internal combustion engine 1 was operated at the rotational speeds of 1,500 rpm and 6,000 rpm. As can be appreciated from FIG.
  • the minimum oil film thickness ho increases with an increase in the second slant angle ⁇ 2 when the second slant angle ⁇ 2 is smaller than about 0.7 degrees, and decreases with an increase in the second slant angle ⁇ 2 when the second slant angle ⁇ 2 is greater than about 0.7 degrees.
  • the friction is minimized when the second slant angle ⁇ 2 is about 0.7 degree where the minimum oil film thickness ho attains the maximum value, and increases thereafter with an increase in the second slant angle ⁇ 2 .
  • the minimum oil film thickness ho increases with an increase in the second slant angle ⁇ 2 when the second slant angle ⁇ 2 is smaller than about 1.2 degrees, and decreases with an increase in the second slant angle ⁇ 2 when the second slant angle ⁇ 2 is greater than about 1.2 degrees.
  • setting the second slant angle ⁇ 2 to a relatively small value such as less than 4.0 degrees is beneficial in reducing the frictional resistance during the upward stroke of the piston 4 .
  • FIG. 8 is a graph showing the influences of the shapes of the outer peripheral surfaces 16 C and 17 C of the side rails 16 and 17 on the consumption of lubricating oil.
  • this graph compares the lubricating oil consumptions (LOC) when the oil ring 13 of the illustrated embodiment is used, and the lubricating oil consumptions (LOC) when a conventional oil ring is used.
  • LOC lubricating oil consumptions
  • the first slant angle ⁇ 1 of the upper side rail 16 was 4.5 degrees
  • the second slant angle ⁇ 2 of the lower side rail 17 was 2.5 degrees
  • the tilt angle was 2.5 degrees.
  • the vertical dimension of each side rail was 500 ⁇ m.
  • the conventional oil ring is similar to the oil ring 13 of the illustrated embodiment except for in the configurations of the outer peripheral surfaces 16 C and 17 C of the upper and lower side rails 16 and 17 .
  • the upper and lower side rails of the conventional oil ring were identical to each other including the slant angles of the major outer peripheral parts thereof.
  • the major outer peripheral surfaces 16 E and 17 E of the conventional oil ring were each given with a zero slant angle, and were each barrel shaped or have a vertical middle part that bulge out radially outward.
  • the internal combustion engine 1 was operated at the rotational speed of 6,800 rpm in Test (1), and at a low rpm that changes cyclically so as to simulate an engine brake condition in Test (2).
  • Test (1) the speed of the movement of the oil ring 13 was so fast that a relatively thick oil film was formed, and each side rail 16 , 17 was significantly lifted away from the wall surface 3 A of the cylinder 3 .
  • Test (2) the speed of the movement of the oil ring 13 was so slow that a relatively thin oil film was formed, and each side rail 16 , 17 was substantially in contact with the wall surface 3 A of the cylinder 3 . Therefore, the lubricating oil consumption was significantly higher in Test (1) than in Test (2).
  • the oil ring 13 of the illustrated embodiment allows the lubricating oil consumption to be reduced as compared with the conventional oil ring. It is surmised that the oil ring 13 of the illustrated embodiment was effective in reducing the lubricating oil consumption in Test (1) because the oil ring 13 of the illustrated embodiment scrapes upward the lubricating oil on the wall surface 3 A of the cylinder during an upward stroke of the piston 4 to a less extent than the convention oil ring. Also, it is surmised that the oil ring 13 of the illustrated embodiment was effective in reducing the lubricating oil consumption in Test (2) because the oil ring 13 of the illustrated embodiment prevents or minimizes the deposition of lubricating oil on top of the piston. Therefore, even when the negative pressure in the combustion chamber is significant as was the case in the condition of Test (2), the amount of lubricating oil drawn into the combustion chamber by the negative pressure was reduced, and the consumption of lubricating oil was minimized.

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  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10253882B2 (en) * 2013-12-30 2019-04-09 Mahle International Gmbh Oil control ring assembly
CN109915130A (zh) * 2017-12-07 2019-06-21 中国石油天然气股份有限公司 一种试油装置及方法
US20200040995A1 (en) * 2017-03-30 2020-02-06 Kabushiki Kaisha Riken Piston and piston ring for internal combustion engine
DE102018119586A1 (de) * 2018-08-13 2020-02-13 Federal-Mogul Burscheid Gmbh Abstreifring für einen dreiteiligen Ölabstreifring und dreiteiliger Ölabstreifring
DE102018120962A1 (de) * 2018-08-13 2020-02-13 Federal-Mogul Burscheid Gmbh Dreiteiliger Ölabstreifring

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102016113678B4 (de) * 2016-07-25 2018-05-09 Federal-Mogul Burscheid Gmbh Einteiliger Ölabstreifring
US11162585B2 (en) * 2019-01-31 2021-11-02 Mahle International Gmbh Piston having two piston rings

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US9915345B2 (en) 2018-03-13

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