Opposed piston engine

• US 20060157003A1
• Filed: 03/17/2006
• Published: 07/20/2006
• Est. Priority Date: 06/10/2004
• Status: Active Grant

• Current Assignee: Achates Power, Inc.
• Original Assignee: Achates Power, Inc.
• Inventors: Lemke, James U., Lee, Patrick R., Wahl, Michael H., Hoffman, Ronald J.
• Granted Patent: US 7,360,511 B2
• Time in Patent Office: Days
• US Class Current: 123/41.380
• CPC Class Codes: F01P 2003/005 the liquid being fuel
• CPC Class Codes: F01P 2003/006 the liquid being oil
• CPC Class Codes: F01P 2003/021 Cooling cylinders
• CPC Class Codes: F01P 2003/027 Cooling cylinders and cylinder heads in parallel
• CPC Class Codes: F01P 2003/028 Cooling cylinders and cylinder heads in series
• CPC Class Codes: F01P 3/06 Arrangements for cooling pistons
• CPC Class Codes: F01P 3/10 Cooling by flow of coolant through pistons
• CPC Class Codes: F02B 75/065 with double connecting rods or crankshafts
• 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
• CPC Class Codes: F02B 75/282 the pistons having equal strokes
• CPC Class Codes: F02B 75/32 Engines characterised by connections between pistons and main shafts and not specific to preceding main groups
• CPC Class Codes: F02F 1/186 for use in engines with two or more pistons reciprocating within same cylinder
• CPC Class Codes: F16H 1/22 with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts

Abstract

A two-cycle, opposed piston engine with side-mounted crankshafts and cylinders isolated from mechanical stresses of the engine includes tailored cooling of cylinders and symmetrical cooling of the interior surfaces of piston crowns. Each opposed piston includes a compliant member that permits movement of an axially-centered rod mounted in the piston in order to maintain axial alignment with the bore of a cylinder in which the piston is disposed during engine operation. A single wristpin is disposed externally of the piston to connect the piston with connecting rods that run between the piston and the crankshafts.

Claims

1. An opposed piston engine including two side-mounted crankshafts and at least one pair of opposed pistons, each piston connected to the two crankshafts by connecting rods and a single wristpin external to the piston.

2. The engine of claim 1, in which each piston includes a cylindrical body, an open end, a closed end defining a crown, and passages positioned for directing symmetric flows of liquid coolant to a back surface of the crown of the piston.

3. The engine of claim 1, further including a rod for each piston, in which each piston includes a cylindrical body with an open end and a closed end defining a crown, each rod having a first end attached to the piston near a back surface of the crown of the piston and a second end extending through the open end of the piston, the single wristpin for the piston being attached to the second end.

4. The engine of claim 3, in which the each rod includes a tubular rod for directing a flow of liquid coolant to the passages.

5. The engine of claim 4, further including means for connecting the bore to a supply of liquid coolant.

6. The engine of claim 1, further including a rod for each piston, each rod having two opposing ends, each piston including a crown and a compliant boot acting between the crown and one end of the respective rod, the single wristpin for the piston mounted on the opposing end of the rod.

7. The engine of claim 1, in which each piston includes a cylindrical body, an open end, and a closed end defining a crown, the cylindrical body exhibiting internal rotational symmetry adjacent the crown.

8. An opposed piston engine without a cylinder block, the engine including at least one cylinder, two side-mounted crankshafts and a frame supporting the cylinder and the crankshafts.

9. The engine of claim 8, in which the at least one cylinder includes:

a liner having an outside surface, central and end portions, and port openings in each end portion;

a sleeve on the liner, the sleeve extending from the central portion toward the end portions; and

,

port manifolds on the liner over the end portions and continuous with the sleeve.

10. The engine of claim 9, in which the at least one cylinder further includes:

groups of grooves that extend on the outside surface of the liner from the central portion toward the end portions, and a group of grooves that extend substantially circumferentially in the central portion; and

one or more pipes in the cylinder sleeve, each pipe in communication with a respective groove and with a source of liquid coolant.

11. An opposed piston internal-combustion engine, comprising:

a cylinder having central and end portions and a bore;

a supply system adapted to apply streams of a liquid coolant to the cylinder that flow from the central portion toward the end portions;

first and second opposed pistons adapted to reciprocate in the bore, each piston including a crown having a back surface;

the supply system further adapted to apply a flow of liquid coolant to an internal portion of each piston on the back surface of the crown of the piston; and

a single wristpin external to each piston.

12. The engine of claim 11, in which the cylinder includes:

a liner having an outside surface with groups of grooves that extend on the outside surface from the central portion toward the end portions, and with a group of grooves that extend substantially circumferentially in the central portion;

a sleeve covering the liner; and

one or more pipes in the sleeve, each pipe in communication with a respective groove, the supply system connected to the one or more pipes.

13. The engine of claim 11, in which each piston includes a cylindrical body, an open end, a closed end defining a crown, and a plurality of passages connected to the supply system and abutting the back surface of the crown.

14. The engine of claim 13, in which the cylinder includes:

a liner having an outside surface with groups of grooves that extend on the outside surface from the central portion toward the end portions, and with a group of grooves that extend substantially circumferentially in the central portion;

a sleeve covering the liner; and

one or more pipes in the sleeve, each pipe in communication with a respective groove, the supply system connected to the one or more pipes.

15. The engine of claim 13, in which each piston includes a longitudinal axis and a rotationally symmetric array of ribs abutting the back surface of the crown and extending radially with respect to the longitudinal axis.

16. The engine of claim 15, further including a rod for each piston, each rod aligned with the longitudinal axis of a respective piston and having a first end connected to the array of ribs of the piston and a second end extending through the open end of the piston, the single wristpin for the piston being mounted to the second end of the rod.

17. The engine of claim 16, in which each rod is a tubular rod, each tubular rod including a bore for conducting the flow of liquid coolant to the plurality of passages.

18. The engine of claim 11, further including a frame, in which the cylinder includes exhaust and inlet ends, an exhaust manifold on the exhaust end, an inlet manifold on the inlet end and at least one bracket, each bracket receivable in the frame.

19. The engine of claim 18, further including an insulating coating on the exhaust manifold.

20. The engine of claim 11, in which each piston includes a cylindrical body having a radius, an open end, a closed end defining a crown, the engine further including a rod for each piston, each rod coaxial with the cylindrical body of a respective piston and having a first end attached to the piston near a back surface of the crown of the piston and a second end extending through the open end of the piston, the single wristpin for the piston being attached to the second end of the tubular rod.

21. The engine of claim 20, in which each rod is a tubular rod with a bore connected to the supply system.

22. The engine of claim 11, wherein the liquid coolant provided to the cylinder and pistons comprises the same liquid coolant.

23. The engine of claim 11, wherein the liquid coolant provided to the cylinder and pistons comprise different liquid coolants.

24. The engine of claim 11, wherein the supply system includes first means for applying a first liquid coolant to the cylinder and a second means for applying a second liquid coolant, different than the first liquid coolant, to the first and second pistons.

25. The engine of claim 11, wherein the supply system includes means for maintaining the cylinder and pistons at respective temperatures.

26. The engine of claim 11, further comprising:

first and second side-mounted crankshafts; and

three or more connecting rods for each piston, each connecting rod connected to the single wristpin for the piston and to one of the crankshafts.

27. The engine of claim 26, wherein the connecting rods are curved.

28. The engine of claim 26, further comprising a frame that supports the crankshafts for rotation.

29. The engine of claim 26, wherein the engine is a two-cycle compression-ignition engine.

30. A machine powered by the engine of claim 11.

31. A vehicle powered by the engine of claim 11.

32. The vehicle of claim 31, wherein the vehicle is a water craft.

33. The vehicle of claim 31, wherein the vehicle is a surface vehicle.

34. The vehicle of claim 31, wherein the vehicle is a fixed-wing aircraft.

35. The vehicle of claim 31, wherein the vehicle is a rotary-wing aircraft.

36. A power tool powered by the engine of claim 11.

37. A power generator powered by the engine of claim 11.

38. An opposed piston internal-combustion engine, comprising:

a cylinder with a liner, the liner having an outside surface, central and end portions, and a bore;

a supply system for applying streams of a liquid coolant on the outside surface that flow from the central portion toward the end portions;

first and second opposed pistons in the bore, each piston including a crown having a back surface and a compliant boot; and

a tubular rod for each piston, each tubular rod having a first end received in the compliant boot of a respective piston and a second end for coupling the piston to crankshafts;

the supply system further for applying a liquid coolant to an internal portion of each piston on the back surface of the crown.

39. In an internal-combustion engine including a cylinder with a liner, the liner having an outside surface, central and end portions, and a bore, the engine further including first and second opposed pistons in the bore, each piston including a crown having a back surface and a rod coupled to each piston for connecting the piston to crankshafts, a method including:

applying streams of a liquid coolant on the outside surface that flow from the central portion toward the end portions; and

,

applying streams of a liquid coolant to an internal portion of each piston on the back surface of the crown.

40. An opposed piston internal-combustion engine, comprising:

a cylinder having a grooved surface, central and end portions, and a bore;

a supply system for applying streams of a liquid coolant to the grooved surface that flow from the central portion toward the end portions; and

first and second opposed pistons in the bore, each piston including a crown having a back surface and a compliant boot;

a rod for each piston, each rod having a first end within received in the compliant boot of the respective piston and a second end outside the piston, and

a single wristpin for each piston, each wristpin mounted on the second end of the rod for the piston;

the supply system further for applying streams of liquid coolant to an internal portion of each piston on the back surface of the crown.

41. An opposed piston internal-combustion engine, comprising:

a cylinder with a liner, the liner having a bore, an outside surface, a central portion, an exhaust end and an inlet end;

a first group of grooves on the outside surface to conduct a liquid coolant from the central portion toward the exhaust end;

a second group of grooves on the outside surface to conduct a liquid coolant from the central portion toward the inlet end;

a third group of grooves on the outside surface to conduct a liquid coolant circumferentially in the central portion;

first and second opposed pistons disposed in the bore, each piston including a crown;

a single wristpin mounted externally to each piston;

a coolant channel to apply streams of a liquid coolant to an internal portion of the first piston on a back surface of the crown; and

a coolant channel to apply streams of a liquid coolant to an internal portion of the second piston on a back surface of the crown.

42. An opposed piston internal-combustion engine, comprising:

a cylinder with a liner, the liner having a bore, an outside surface, a central portion, an exhaust end and an inlet end;

a first group of grooves on the outside surface to conduct a liquid coolant from the central portion toward the exhaust end;

a second group of grooves on the outside surface to conduct a liquid coolant from the central portion toward the inlet end;

a third group of grooves on the outside surface to conduct a liquid coolant circumferentially in the central portion;

first and second opposed pistons disposed in the bore, each piston including a crown and means for compliant adjustment of the piston with respect to the cylinder;

a plurality of passages in the first piston to apply streams of a liquid coolant to an internal portion of the first piston on a back surface of the crown; and

a plurality of passages in the second piston to apply streams of a liquid coolant to an internal portion of the second piston on a back surface of the crown.

43. An opposed piston internal-combustion engine, comprising:

a cylinder with a liner, the liner having a bore, an outside surface, a central portion, an exhaust end and an inlet end;

a first group of grooves on the outside surface to conduct a liquid coolant from the central portion toward the exhaust end;

a second group of grooves on the outside surface to conduct a liquid coolant from the central portion toward the inlet end;

a third group of grooves on the outside surface to conduct a liquid coolant circumferentially in the central portion;

first and second opposed pistons disposed in the bore, each piston including a crown and means for compliant adjustment of the piston with respect to the cylinder;

a single wristpin mounted externally to each piston;

a plurality of passages in the first piston to apply streams of a liquid coolant to an internal portion of the first piston on a back surface of the crown; and

a plurality of passages in the second piston to apply streams of a liquid coolant to an internal portion of the second piston on a back surface of the crown.

44. An opposed piston internal-combustion engine, comprising:

a cylinder with a liner, the liner having an outside surface, central and end portions, and a bore;

a supply system for applying streams of a liquid coolant on the outside surface that flow from the central portion toward the end portions;

first and second opposed pistons adapted to reciprocate in the bore; and

a single wristpin mounted to each piston to couple reciprocating motion to the piston.

45. An opposed piston internal-combustion engine, comprising:

a cylinder with a grooved surface, central and end portions, and a bore;

a supply system for applying streams of a liquid coolant on the grooved surface that flow from the central portion toward the end portions;

first and second opposed pistons adapted to reciprocate in the bore;

a single wristpin mounted to each piston to couple reciprocating motion to the piston; and

,

means in each piston for compliant adjustment of the piston with respect to the cylinder.

46. The engine of claim 45, wherein each piston includes a crown having a back surface, the supply system further for applying a liquid coolant to an internal portion of each piston on the back surface of the crown.

47. The engine of claim 46, in which each piston includes a cylindrical body, an open end and a closed end defining a crown, the engine further including a rod for each piston, each rod having a first end connected to the means for compliant adjustment of a respective piston and a second end to which the single wristpin for the piston is mounted, the rod including a bore connected to the supply system and positioned for directing a stream of liquid coolant toward the back surface of the crown of the piston.

48. The engine of claim 47, in which groups of grooves extend on the grooved surface from the central portion toward the end portions, and a group of grooves extend substantially circumferentially on the grooved surface in the central portion, further including a sleeve covering the grooved surface and one or more pipes in the sleeve, each pipe in communication with a respective groove, the supply system connected to the one or more pipes.

49. An opposed piston engine including two side-mounted crankshafts, at least one pair of opposing pistons, and a single wristpin external to each piston for coupling the respective piston to the two crankshafts.

50. The engine of claim 49, in which each piston includes a cylindrical body, an open end, a closed end defining a crown, and flow passages positioned for directing symmetric flows of liquid coolant to the back surface of the crown of the piston.

51. The engine of claim 49, in which each piston includes a cylindrical body with an open end and a closed end defining a crown, the engine further including a rod for each piston, each rod being coaxial with the cylindrical body of a respective piston and having a first end attached to the piston near the back surface of the crown of the piston and a second end extending through the open end of the piston, the single wristpin for the piston being attached to the second end of the rod.

52. The engine of claim 51, in which each rod is a tubular rod with a bore for directing a flow of liquid coolant toward the back surface of the crown of a respective piston.

53. The engine of claim 52, further including means for connecting the bore to a supply of liquid coolant.

54. The engine of claim 49, each piston including a crown and a compliant boot, the engine further including a rod for each piston, each rod having two opposing ends, the compliant boot of each piston acting between the crown of the piston and one end of a respective rod, the single wristpin for the piston being mounted on the opposing end of the rod.

55. The engine of claim 54, each rod being a tubular rod.

56. An opposed piston engine including at least one cylinder that is primarily a cooled pressure vessel.

57. The engine of claim 56, further including a frame supporting the cylinder.

58. The engine of claim 57, in which the cylinder includes:

a liner having an outside surface, central and end portions, and port openings in each end portion;

a sleeve on the liner extending from the central portion toward the end portions; and

,

port manifolds on the liner over the end portions and continuous with the sleeve.

59. The engine of claim 58, in which the cylinder further includes:

groups of grooves that extend on the outside surface of the liner from the central portion toward the end portions, and a group of grooves that extend substantially circumferentially in the central portion; and

one or more pipes in the sleeve, each pipe in communication with a respective groove and with a source of liquid coolant.

60. An internal combustion engine, comprising:

a cylinder having a bore;

a piston adapted to reciprocate in the bore;

a rod; and

a coupling between the rod and the piston, the coupling including a member that resiliently deforms to at least substantially maintain axial alignment of the piston with the bore during engine operation.

61. The engine of claim 60, the member including a compliant boot.

62. In an internal combustion engine including a cylinder having a bore, a piston adapted to reciprocate in the bore, and a rod, a method comprising resiliently deforming a compliant member between the rod and piston during piston movement so as to at least substantially maintain axial alignment of the piston with the bore during engine operation.

63. In an opposed piston internal combustion engine including a cylinder having a bore, a pair of pistons adapted to reciprocate in the bore, and a rod for each piston, a method comprising resiliently deforming a compliant member between a respective rod and a respective piston during piston movement so as to at least substantially maintain axial alignment of the respective piston with the bore during engine operation.

64. The method of claim 63, further comprising supplying liquid coolant separately to the cylinder and to the pistons so as to at least essentially maintain a mechanical clearance between the pistons and the bore of the cylinder.

65. An internal combustion engine, including:

a cylinder having a bore;

a pair of opposed pistons adapted to reciprocate in the bore;

a rod for each piston, each rod connected to at least one crankshaft; and

a compliant boot for each piston, each compliant boot connecting a respective piston to a respective rod.

66. An opposed piston internal-combustion engine, comprising:

at least one cylinder having a bore;

first and second opposed pistons disposed in the bore;

a system to apply a liquid coolant separately to the cylinder and pistons; and

,

a controller to cause the system to maintain and vary the temperature of the cylinder separately from the temperatures of the pistons.

67. A method of operating an internal-combustion engine with at least one cylinder and a pair of opposed pistons disposed in a bore of the at least one cylinder, comprising:

applying a liquid coolant separately to the at least one cylinder and to the opposed pistons; and

causing the application of the liquid coolant to independently control temperatures of the at least one cylinder and the opposed piston.