Differential stroke internal combustion engine

• US 5,243,938 A
• Filed: 07/30/1992
• Issued: 09/14/1993
• Est. Priority Date: 07/30/1992
• Status: Expired due to Fees

• Current Assignee: Miin J. Yan
• Original Assignee: Miin J. Yan
• Inventors: Yan, Miin J.
• Primary Examiner(s): Cross, E. Rollins
• Assistant Examiner(s): MCMAHON, MARGUERITE J
• Application Number:
  US07/921,827
• Time in Patent Office: 411 Days
• Field of Search: 123/197.1, 123/197.2, 123/197.4, 123/71 R
• US Class Current: 123/197.1
• CPC Class Codes: F02B 2075/023 one
• CPC Class Codes: F02B 2075/025 two
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 41/04 in main cylinders
• CPC Class Codes: F02B 75/02 Engines characterised by their cycles, e.g. six-stroke
• CPC Class Codes: F02B 75/28 Engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders arranged oppositely relative to main shaft F02B75/24

Abstract

An internal reciprocating engine effective to operate at one engine cycle per revolution is provided with a differential stroke piston having an inner piston part, for sealing the cylinder, operating at a cycle different from its corresponding outer piston part, for transmitting power to and from the engine shaft, and a differential stroke actuating means for operating the inner and outer piston parts in the same and the opposite directions within the cylinder and to provide differential stroke periods and/or stroke lengths for the inner piston part cycle.

Claims

1. A differential stroke piston apparatus for a reciprocating internal combustion engine having at least one cylinder chamber, said differential stroke piston apparatus comprising:

a differential stroke piston effective for reciprocal operation in the engine cylinder chamber,

said differential stroke piston having an inner piston part which closes and seals the cylinder chamber and an outer piston part which serves as a carrier for the inner piston part and is connected to an engine shaft,

an inner piston part actuation means to operate said inner piston part at an inner piston part cycle different from an outer piston part cycle, and

said inner piston part actuation means further comprises a differential stroke control means operable to control a stroke length parameter such that said stroke stroke length parameter has at least two different values during an engine cycle.

2. A differential stroke piston apparatus as claimed in claim 1 wherein said inner piston part actuation means further comprises a variable cycle means.

3. A differential stroke piston apparatus as claimed in claim 1 further comprises:

said outer piston part cycle being a two stroke cycle comprising an outer inward stroke followed by an outer outward stroke during each engine shaft revolution,

said inner piston part cycle being a four stroke cycle comprising in order of occurrence compression, power, exhaust, and intake strokes during each engine shaft revolution, and

said inner piston part actuation means operable to allow said inner piston part to be carried by said outer piston part during substantially its compression and power strokes.

4. A differential stroke piston apparatus as claimed in claim 3 wherein said differential stroke control means is operable to provide a power stroke length greater than a compression stroke length of said inner piston part cycle.

5. A differential stroke piston apparatus as claimed in claim 3 wherein said differential stroke control means is operable to provide at least one of an intake stroke length and intake stroke period that is greater than at least one of a corresponding one of an exhaust stroke length and exhaust stroke period of said inner piston part cycle.

6. A differential stroke piston apparatus as claimed in claim 1 wherein said inner piston part actuation means includes an unsymmetrical cam means to provide said at least one differential set of said stroke parameters.

7. A differential stroke piston apparatus as claimed in claim 6 wherein said unsymmetrical cam means further comprises a cam mounted on said engine shaft.

8. A differential stroke piston apparatus as claimed in claim 1 wherein said inner piston part actuation means further comprises a lever means including a lever bar operatively connected to said inner piston part such that said inner piston part is operable to provide a load for said lever bar.

9. A differential stroke piston apparatus as claimed in claim 8 wherein said lever means further comprises a fulcrum means having a four-bar linkage including said lever bar.

10. A differential stroke piston apparatus as claimed in claim 9 wherein said inner piston part actuation means includes an unsymmetrical cam means to provide said one differential set of said stroke parameters and said unsymmetrical cam means is operatively connected to said four-bar linkage such that said unsymmetrical cam means is operable to provide a force for said lever bar.

11. A differential stroke piston apparatus as claimed in claim 10 wherein said unsymmetrical cam means further comprises a cam having a cam surface around its periphery,

said cam mounted on said engine shaft,

a cam rocker means operatively engaged with said cam surface in a cam following manner, and

said cam rocker means operatively connected to said four-bar linkage to provide the force for said lever bar.

12. A differential stroke piston apparatus as claimed in claim 8 wherein said inner piston part actuation means further comprises a lever means including a lever bar supported by an accommodating fulcrum means and said lever bar operatively connected at its distal end to said inner piston part such that said inner piston part is operable to provide a load for said lever bar.

13. A differential stroke piston apparatus as claimed in claim 12 wherein said inner piston part actuation means includes an unsymmetrical cam means further comprising an unsymmetrical cam having a cam surface around its periphery,

said unsymmetrical cam mounted on said engine shaft,

a cam rocker means operatively engaged with said cam surface in a cam following manner, and

a cam rocker means operatively connected to said lever means to provide the force for said lever bar.

14. A differential stroke piston apparatus as claimed in claim 1 wherein:

said inner piston part further comprises a stem depending from said inner piston part,

said outer piston part further comprises a pin means pivotably connected to said engine shaft by a connecting means, and

said stem slidably disposed through said pin means and operably connected at its distal end to said inner piston part actuation means.

15. A differential stroke piston apparatus as claimed in claim 14 further wherein said differential stroke piston further comprises:

a piston part mating means for operably mating said outer piston part to said inner piston part during engine operation so as to allow the outer piston part to effectively serve as a carrier for the inner piston part during at least a portion of said inner and outer piston part cycles,

said piston parts mating means comprising conical surface mating elements including;

an inner piston part conical surface mating element having an inner convex conical surface and an outer piston part conical surface mating element having a correspondingly matching outer concave conical surface, and

an outer piston part conical surface mating element having an outer convex conical surface and an inner piston part conical surface mating element having a correspondingly matching inner concave conical surface.

16. A differential stroke piston apparatus as claimed in claim 15 further comprising:

said outer piston part having a hollow cylindrical outer skirt slidably disposed within the cylinder,

said pin means having a wrist pin attached to said outer skirt,

said piston parts mating means further comprising a hub like saddle suspended in the center of said outer skirt by a plurality of struts extending from said saddle to said outer skirt,

said saddle having a saddle bore axially extending therethrough, said saddle bore operable to allow said stem to pass through said saddle bore, and

said saddle having a bottom surface in bearing contact with said wrist pin.

17. A differential stroke piston apparatus as claimed in claim 14 further comprising:

said outer piston part having a hollow cylindrical outer skirt slidably disposed within the cylinder,

said piston parts further comprising a mating means in bearing contact with and substantially suspended in the center of said outer skirt by said pin means.

18. A differential stroke piston apparatus as claimed in claim 17 wherein:

said connecting means further comprises a connecting rod having an upper end bearing and a lower end bearing and said connecting rod is pivotably connected within said hollow cylindrical outer skirt by said pin means,

said pin means is disposed through an axial bore of said upper end bearing of said connecting rod, and

a notch in said upper end bearing operable to pivotably receive a portion of said mating means.

19. A differential stroke piston apparatus as claimed in claim 14 wherein said pin means includes a wrist pin and said connecting means further comprises:

a connecting rod having an integral upper bearing pivotally connected to said wrist pin,

slots disposed in the upper and lower sides respectively of said upper bearing, and

said stem is movably disposed through said slots so as allow said stem to pass through said upper bearing as said connecting rod pivots on said wrist pin.

20. A differential stroke piston apparatus as claimed in claim 19 wherein said connecting rod further comprises:

two spaced apart legs integrally connected between said upper end bearing and said lower end bearing which is connected to said engine shaft, and

said two spaced apart legs form a space there between wherein said stem and said inner piston part actuation means are operably disposed to pass between said legs within said space.

21. A differential stroke piston apparatus as claimed in claim 8 wherein said inner piston part actuation means further includes a variable cycle means that is operatively connected to said lever bar such that said variable cycle means is operable to provide a force for said lever bar and said variable cycle means includes a control means to vary at least one of said stroke parameters during the engine'"'"'s operation.

22. A differential stroke piston apparatus as claimed in claim 21 wherein said variable cycle means is an electrically powered actuation means for actuating said lever bar.

23. A differential stroke piston apparatus as claimed in claim 21 wherein said variable cycle means is an hydraulically powered actuation means for actuating said lever bar.

24. A differential stroke piston apparatus as claimed in claim 21 wherein said variable cycle means is a pneumatically powered actuation means for actuating said lever bar.

25. A differential stroke piston apparatus as claimed in claim 1 further comprising an engine control means for operating the engine so as to complete a combustion cycle in the cylinder chamber during one engine shaft revolution, and

said control means further comprising a cam on a balancing weight mounted on said engine shaft, said cam operable to actuate intake and exhaust valves.

26. A differential stroke piston apparatus as claimed in claim 2 wherein said variable cycle means further includes an electronic control means to control said inner piston part actuation means.

27. A differential stroke piston apparatus as claimed in claim 2 wherein said variable cycle means is a digital electronic control means to control said inner piston part actuation means.

28. A split piston apparatus for a reciprocating internal combustion engine having at least one engine cylinder chamber, said split piston apparatus comprising:

a split piston effective for reciprocal operation in the engine cylinder chamber;

said split piston having an inner piston part operable to close and seal the cylinder chamber;

said split piston having an outer piston part that is operable as a carrier for the inner piston part during substantially the compression and power strokes of the engine'"'"'s cycle, and is connected to an engine shaft;

an inner piston part actuation means to operate said inner piston part at an inner piston part cycle different from an outer piston part cycle; and

said inner piston part actuation means further comprises a lever means including a lever bar operatively connected to said inner piston part such that said inner piston part is operable to provide a load for said lever bar during the exhaust and intake stokes of the engine'"'"'s cycle.

29. A split piston apparatus as claimed in claim 28 wherein said inner piston part actuation means further comprises a cam means to help control the stroke length and period of the engine'"'"'s cycle.

30. A split piston apparatus as claimed in claim 28 wherein said lever means further comprises a fulcrum means having a four-bar linkage including said lever bar.

31. A split piston apparatus as claimed in claim 30 wherein said inner piston part actuation means includes a cam means to control the stroke length and stroke period of said inner piston part cycle and said cam means is operatively connected to said four-bar linkage such that said cam means is operable to provide a force for said lever bar.

32. A split piston apparatus as claimed in claim 31 wherein said cam means further comprises a cam having a cam surface around its periphery,

said cam mounted on said engine shaft,

a cam rocker means operatively engaged with said cam surface in a cam following manner, and

rocker means operatively connected to said four-bar linkage to provide the force for said lever bar.

33. A split piston apparatus as claimed in claim 28 wherein said lever bar is supported by an accommodating fulcrum means and said lever bar is operatively connected at its distal end to said inner piston part such that said inner piston part is operable to provide a load for said lever bar.

34. A split piston apparatus as claimed in claim 29 wherein said cam means further comprises a cam having a cam surface around its periphery,

said cam mounted on said engine shaft,

a cam rocker means operatively engaged with said cam surface in a cam following manner, and

said cam rocker means operatively connected to said lever means to provide the force for said lever bar.

35. A split piston apparatus as claimed in claim 28 wherein:

said inner piston part further comprises a stem depending from said inner piston part,

said outer piston part further comprises a pin means pivotably connected to said engine shaft by a connecting means, and

said stem slidably disposed through said pin means and operably connected at its distal end to said inner piston part actuation means.

36. A split piston apparatus as claimed in claim 35 wherein said split piston further comprises:

a piston part mating means for operably mating said outer piston part to said inner piston part during engine operation so as to allow the outer piston part to effectively serve as a carrier for the inner piston part during at least a portion of said inner and outer piston part cycles,

said piston parts mating means comprising conical surface mating elements including;

an inner piston part conical surface mating element having an inner convex conical surface and an outer piston part conical surface mating element having a correspondingly matching outer concave conical surface, and

an outer piston part conical surface mating element having an outer convex conical surface and an inner piston part conical surface mating element having a correspondingly matching inner concave conical surface.

37. A split piston apparatus as claimed in claim 36 further comprising:

said outer piston part having a hollow cylindrical outer skirt slidably disposed within the cylinder,

said pin means having a wrist pin attached to said outer skirt,

said piston parts mating means further comprising a hub like saddle suspended in the center of said outer skirt by a plurality of struts extending from said saddle to said outer skirt,

said saddle having a saddle bore axially extending therethrough, said saddle bore operable to allow said stem to pass through said saddle bore, and

said saddle having a bottom surface in bearing contact with said wrist pin.

38. A split piston apparatus as claimed in claim 35 further comprising:

said outer piston part having a hollow cylindrical outer skirt slidably disposed within the cylinder,

said piston parts further comprising a mating means in bearing contact with and substantially suspended in the center of said outer skirt by said pin means.

39. A split piston apparatus as claimed in claim 38 wherein:

said connecting means further comprises a connecting rod having an upper end bearing and a lower end bearing and said connecting rod is pivotably connected within said hollow cylindrical outer skirt by said pin means,

said pin means is disposed through an axial bore of said upper end bearing of said connecting rod, and

a notch in said upper end bearing operable to pivotably receive a portion of said mating means.

40. A split piston apparatus as claimed in claim 35 wherein said pin means includes a wrist pin and said connecting means further comprises:

a connecting rod having an integral upper bearing pivotally connected to said wrist pin,

slots disposed in the upper and lower sides respectively of said upper bearing, and

said stem is movably disposed through said slots so as allow said stem to pass through said upper bearing as said connecting rod pivots on said wrist pin.

41. A split piston apparatus as claimed in claim 40 wherein said connecting rod further comprises:

two spaced apart legs integrally connected between said upper end bearing and said lower end bearing which is connected to said engine shaft, and

said two spaced apart legs form a space there between wherein said stem and said inner piston part actuation means are operably disposed to pass between said legs within said space.

42. A split piston apparatus as claimed in claim 28 wherein said inner piston part actuation means further includes a variable cycle means that is operatively connected to said lever bar such that said variable cycle means is operable to provide a force for said lever bar and said variable cycle means includes a control means to vary at least one inner piston part stroke parameter of a set of inner piston part cycle parameters during the engine'"'"'s operation wherein said inner piston part cycle parameters include inner piston part stroke length and inner piston part stroke period.

43. A differential stroke piston apparatus for a reciprocating internal combustion engine having at least one cylinder chamber, said differential stroke piston apparatus comprising:

a differential stroke piston effective for reciprocal operation in the engine cylinder chamber,

said differential stroke piston having an inner piston part which closes and seals the cylinder chamber and an outer piston part which serves as a carrier for the inner piston part and is connected to an engine shaft;

an inner piston part actuation means to operate said inner piston part at an inner piston part cycle different from an outer piston part cycle, and

said inner piston part actuation means further comprises a differential stroke control means operable to control an intake stroke period and an exhaust stroke period to said inner piston part cycle such that said intake stroke and exhaust stroke periods are unequal during an engine cycle.