Claims
- 1. A piston ring for a non-circular engine cylinder, which cylinder has a wall contacted by the ring, the cylinder being in an engine which is in a cold state before being placed into operation, said ring having a plurality of first circumferential regions spaced apart around the circumference of said ring and each having a defined radius of curvature which differs from one first region to the next around the circumference of said ring, and a plurality of second circumferential regions each interposed between two succeeding first regions and each formed to effect a transition between the radii of curvature of the two succeeding first regions, wherein said second regions are configured for exerting on the cylinder wall a radial contact pressure which is less than that exerted by said first regions when said ring is installed in the cylinder and the engine is in its cold state.
- 2. A piston ring as defined in claim 1, wherein the change in curvature of the circumference of said ring between a non-installed and an installed mode is determined by a differential equation as follows: ##EQU2## where .DELTA.k.sub..DELTA. is the change in curvature between the installed state and the non-installed state;
- u, v.sub..DELTA. are the cartesian coordinates of the non-installed state after solving the differential equation;
- x, y.sub..DELTA. are the cartesian coordinates of the installed state after solving the differential equation;
- M.sub..DELTA. is the moment generated by the contact pressure;
- E.sub..DELTA. is the modulus of elasticity;
- I.sub..DELTA. is the moment of surface inertial;
- v'=.sub..DELTA. dv/du is the first derivative of v with respect to u;
- v"=.sub..DELTA. d.sup.2 v/du.sup.2 is the second derivative of v with respect to u;
- y'=.sub..DELTA. dy/dx is the first derivative of y with respect to x; and
- y"=.sub..DELTA. d.sup.2 y/dx.sup.2 is the second derivative of y with respect to x.
- 3. A piston ring as defined in claim 1 wherein each said second region has a circumferential extent of 5.degree. to 45.degree., as a function of the contour of said ring.
- 4. A piston ring as defined in claim 1 wherein said second regions are configured for exerting on the cylinder wall a radial contact pressure which is less than that exerted by said first regions when the engine is in operation.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3515659 |
May 1985 |
DEX |
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Parent Case Info
This application is a continuation of application Ser. No. 06/858,494, filed Apr. 30, 1986, now abandoned.
US Referenced Citations (3)
Foreign Referenced Citations (2)
Number |
Date |
Country |
3032722 |
Apr 1982 |
DEX |
714364 |
Aug 1954 |
GBX |
Non-Patent Literature Citations (2)
Entry |
Standard Handbook for Mechanical Engineers, 7th ed, edited by T. Baumeister, McGraw Hill, pp. 5-42 and 2-70. |
"Reference Data for Radio Engineers", 4th ed., ITT, p. 1064. |
Continuations (1)
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Number |
Date |
Country |
Parent |
858494 |
Apr 1986 |
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