Combustion chamber

• US 6,601,561 B1
• Filed: 01/30/2002
• Issued: 08/05/2003
• Est. Priority Date: 01/30/2002
• Status: Expired due to Fees

• Current Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Original Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Inventors: Liu, Zhengbai, Gui, Xinqun
• Primary Examiner(s): Argenbright, Tony M.
• Assistant Examiner(s): Harris, Katrina B.
• Application Number:
  US10/060,663
• Publication Number:
  US 20030140890A1
• Time in Patent Office: 552 Days
• Field of Search: 123/279, 123/263, 123/276
• US Class Current: 123/276
• CPC Class Codes: F02B 23/0672 Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis the surrounding wall being exactly vertical F02B23/0696
• 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: Y02T 10/12 Improving ICE efficiencies

Abstract

A combustion chamber assembly for use in a diesel engine includes a combustion chamber being defined in a crown of a piston, the combustion chamber having a center portion, the center portion being defined at least in part by a portion of a convex sphere to define a post, the sphere having a radius and an origin, the origin of the radius lying on a combustion chamber central axis and the combustion chamber further having an outwardly radially disposed bottom margin, the bottom margin being defined in part by a portion of a sphere, the sphere being concave and having an origin and a radius. The combustion chamber has more than two spherical surfaces having smooth annular transitions between adjacent spherical surfaces, the spherical surfaces including the spherical center portion and the spherical bottom margin. A piston and a method of forming a combustion chamber are further included.

Claims

1. A combustion chamber assembly for use in a diesel engine, comprising:

a combustion chamber being defined in a crown of a piston, the combustion chamber having a center portion, the center portion being defined at least in part by a portion of a convex sphere to define a post, the sphere having a radius and an origin, the origin of the radius lying on a combustion chamber central axis and the combustion chamber further having an outwardly radially disposed bottom margin, the bottom margin being defined in part by a portion of a sphere, the sphere being concave and having an origin and a radius; and

the combustion chamber having more than two spherical surfaces having smooth annular transitions between adjacent spherical surfaces, the spherical surfaces including the spherical center portion and the spherical bottom margin.

2. The combustion chamber assembly of claim 1 wherein the origins of the post and the lower sidewall spherical surfaces are co-centric and lie on the center axis of the combustion chamber.

3. The combustion chamber assembly of claim 2 wherein the side wall portion of the combustion chamber is substantially defined by two spherical surfaces.

4. The combustion chamber assembly of claim 3 wherein the two spherical surfaces substantially defining the side wall portion of the combustion are joined by an annular surface.

5. The combustion chamber assembly of claim 3 wherein a one of the two spherical surfaces substantially defining the higher side wall portion of the combustion is transitioned by an annular surface to a piston crown.

6. The combustion chamber assembly of claim 1 wherein the ratio of the radius of the center portion convex spherical surface, RS1, of the combustion chamber to the piston diameter, D1, is greater than 0.05 and less than 0.35.

7. The combustion chamber assembly of claim 6 wherein the ratio of the radius of the center portion convex spherical surface, RS1, of the combustion chamber to the piston diameter, D1, is substantially 0.18.

8. The combustion chamber assembly of claim 1 wherein the ratio of the combustion chamber diameter D2 to the piston diameter D1 is greater than 0.43 and less than 0.83.

9. The combustion chamber assembly of claim 8 wherein the ratio of the combustion chamber diameter D2 to the piston diameter D1 is preferably substantially 0.637.

10. The combustion chamber assembly of claim 1 wherein the ratio of the diameter of the reentrancy D3 to the piston diameter D1 is greater than 0.33 and less than 0.83.

11. The combustion chamber assembly of claim 10 wherein the ratio of the diameter of the reentrancy D3 to the piston diameter D1 is substantially 0.548.

12. The combustion chamber assembly of claim 1 wherein the ratio of the radius of the center convex spherical surface RS1 to the diameter of the piston D1 is greater than 0.05 and less than 0.35.

13. The combustion chamber assembly of claim 12 wherein the ratio of the radius of the center convex spherical surface RS1 to the diameter of the piston D1 is substantially 0.018.

14. The combustion chamber assembly of claim 1 wherein the ratio of the spherical surface RS2 to the diameter of the piston D1 is between 0.23 and 0.53.

15. The combustion chamber assembly of claim 14 wherein the ratio of the spherical surface RS2 to the diameter of the piston D1 is preferably substantially 0.334.

16. The combustion chamber assembly of claim 1 wherein the ratio of the spherical surface RS3 to the diameter of the piston D1 is between 1.18 and 4.18.

17. The combustion chamber assembly of claim 16 wherein the ratio of the spherical surface RS3 to the diameter of the piston D1 is preferably substantially 2.18.

18. The combustion chamber assembly of claim 1 wherein the ratio of the spherical surface RS4 to the diameter of the piston D1 is between 0.18 and 0.38.

19. The combustion chamber assembly of claim 18 wherein the ratio of the spherical surface RS4 to the diameter of the piston D1 is preferably substantially 0.28.

20. The combustion chamber assembly of claim 1 wherein the ratio of the depth dimension of the combustion chamber H1 to the diameter D1 of the piston is greater than 0.1 and less than 0.4.

21. The combustion chamber assembly of claim 20 wherein the ratio of the distance H1 to the diameter D1 of the piston is preferably substantially 0.2.

22. The combustion chamber assembly of claim 1 wherein the ratio of the certain distance H2, H2 being the post height distance from a peak of the center portion convex spherical surface to the bottom plane of the combustion chamber, to the diameter D1 of the piston is greater than 0.04 and less than 0.24.

23. The combustion chamber assembly of claim 22 wherein the ratio of the certain distance H2 to the diameter D1 is preferably substantially 0.144.

24. The combustion chamber assembly of claim 1 wherein the radius of the annular surface R1 is equal to the radius of the annular surface R2.

25. The combustion chamber assembly of claim 1 wherein the ratio of the annular surface radius R1 to the diameter of the piston D1 and the annular surface R2 to the diameter D1 are each greater than 0.03 and less than 0.25.

26. The combustion chamber assembly of claim 25 wherein the ratio of the annular sidewall surface radius R1 to the diameter of the piston D1 and the annular surface R2 to the diameter D1 are each preferably substantially 0.051.

27. The combustion chamber assembly of claim 1 wherein the ratio of the annular surface radius R3 to the diameter of the piston D1 and the ratio of the annular surface radius R4 to the diameter of the piston D1 are each greater than 0.0 and less than 0.1.

28. The combustion chamber assembly of claim 1 wherein the distance between the co-center of the spherical surfaces RS1, RS2 and the point of intersection of a combustion chamber axis with a bottom plane of the combustion chamber is less than 0.28 the piston diameter D1.

29. The combustion chamber assembly of claim 28 wherein the distance between the co-center of the spherical surfaces RS1, RS2 and the point of intersection of a combustion chamber axis with a bottom plane of the combustion chamber is preferably 0.073 D1.

30. The combustion chamber assembly of claim 1 wherein the origin of a spherical surface RS3 is on a central axis of the combustion chamber.

31. The combustion chamber assembly of claim 30 wherein the distance between the origin of the spherical surface RS3 and a point of intersection of the central axis of the combustion chamber with a bottom plane of the combustion chamber is greater than 0.75 the piston diameter D1 and less than 3.0 D1.

32. The combustion chamber assembly of claim 31 wherein the distance between the origin of the spherical surface RS3 and the point of intersection of the central axis of the combustion chamber with the bottom plane of the combustion chamber is preferably 2.178 D1.

33. The combustion chamber assembly of claim 1 wherein the origin of a spherical surface RS4 is on a combustion chamber central axis and the distance between the origin of the spherical surface RS4 and a point of intersection of the central axis of the combustion chamber with a top plane of the combustion chamber is the height H3 greater than 0.02 the piston diameter D1 and less than 0.42 D1.

34. The combustion chamber assembly of claim 33 wherein the ratio of the height H3 to the diameter of the piston D1 is greater than 0.02 and less than 0.42.

35. The combustion chamber assembly of claim 34 wherein the ratio of the height H3 to the diameter of the piston D1 is preferably substantially 0.051.

36. The combustion chamber assembly of claim 1 the combustion chamber having a central axis, the combustion chamber central axis being coincident with a piston central axis.

37. The combustion chamber assembly of claim 1 the combustion chamber having a central axis, the combustion chamber central axis being offset from a piston central axis.

38. The combustion chamber assembly of claim 37 the combustion chamber having a central axis, the combustion chamber central axis being offset from the piston central axis less than a distance equal to 0.1 the piston diameter D1.

39. The combustion chamber assembly of claim 1 being formed free of flat surfaces.

40. A piston for use in a diesel engine, the piston having a central axis, comprising:

a combustion chamber being defined in a crown of the piston, the combustion chamber having a center portion, the center portion being defined at least in part by a portion of a convex sphere to define a post, the sphere having a radius and an origin, the origin of the radius lying on a combustion chamber central axis and the combustion chamber further having an outwardly radially disposed bottom margin, the bottom margin being defined in part by a portion of a sphere, the sphere being concave and having an origin and a radius; and

the combustion chamber having more than two spherical surfaces having smooth annular transitions between adjacent spherical surfaces, the spherical surfaces including the spherical center portion and the spherical bottom margin.

41. The piston of claim 40 wherein the origin of the post and the lower sidewall spherical surfaces are co-centric and lie on the center axis of the combustion chamber.

42. The piston of claim 41 wherein the side wall portion of the combustion chamber is substantially defined by two spherical surfaces.

43. The piston of claim 42 wherein the two spherical surfaces substantially defining the side wall portion of the combustion chamber are joined by an annular surface.

44. The piston of claim 42 wherein a one of the two spherical surfaces substantially defining the higher side wall portion of the combustion is transitioned by an annular surface to a piston crown.

45. The piston of claim 40 wherein the ratio of the radius of the center portion convex spherical surface, RS1, of the combustion chamber to the piston diameter, D1, is greater than 0.05 and less than 0.35.

46. The piston of claim 45 wherein the ratio of the radius of the center portion convex spherical surface, RS1, of the combustion chamber to the piston diameter, D1, is substantially 0.18.

47. The piston of claim 40 wherein the ratio of the combustion chamber diameter D2 to the piston diameter D1 is greater than 0.43 and less than 0.83.

48. The piston of claim 47 wherein the ratio of the combustion chamber diameter D2 to the piston diameter D1 is preferably substantially 0.637.

49. The piston of claim 40 wherein the ratio of the diameter of the reentrancy D3 to the piston diameter D1 is greater than 0.33 and less than 0.83.

50. The piston of claim 49 wherein the ratio of the diameter of the reentrancy D3 to the piston diameter D1 is substantially 0.548.

51. The piston of claim 40 wherein the ratio of the radius of the center convex spherical surface RS1 to the diameter of the piston D1 is greater than 0.05 and less than 0.35.

52. The piston of claim 51 wherein the ratio of the radius of the center convex spherical surface RS1 to the diameter of the piston D1 is substantially 0.018.

53. The piston of claim 40 wherein the ratio of the spherical surface RS2 to the diameter of the piston D1 is between 0.23 and 0.53.

54. The piston of claim 53 wherein the ratio of the spherical surface RS2 to the diameter of the piston D1 is preferably substantially 0.334.

55. The piston of claim 40 wherein the ratio of the spherical surface RS3 to the diameter of the piston D1 is between 1.18 and 4.18.

56. The piston of claim 55 wherein the ratio of the spherical surface RS3 to the diameter of the piston D1 is preferably substantially 2.18.

57. The piston of claim 40 wherein the ratio of the spherical surface RS4 to the diameter of the piston D1 is between 0.18 and 0.38.

58. The piston of claim 57 wherein the ratio of the spherical surface RS4 to the diameter of the piston D1 is preferably substantially 0.28.

59. The piston of claim 40 wherein the ratio of the depth dimension of the combustion chamber H1 to the diameter D1 of the piston is greater than 0.1 and less than 0.4.

60. The piston of claim 59 wherein the ratio of the distance H1 to the diameter D1 of the piston is preferably substantially 0.2.

61. The piston of claim 40 wherein the ratio of the certain distance H2, H2 being the post height distance from a peak of the center portion convex spherical surface to the bottom plane of the combustion chamber, to the diameter D1 of the piston is greater than 0.04 and less than 0.24.

62. The piston of claim 61 wherein the ratio of the certain distance H2 to the diameter D1 is preferably substantially 0.144.

63. The piston of claim 40 wherein the radius of the annular surface R1 is equal to the radius of the annular surface R2.

64. The piston of claim 40 wherein the ratio of the annular surface radius R1 to the diameter of the piston D1 and the ratio of the annular surface R2 to the diameter D1 are each greater than 0.03 and less than 0.25.

65. The piston of claim 64 wherein the ratio of the annular surface radius R1 to the diameter of the piston D1 and the annular.surface R2 to the diameter D1 are each preferably substantially 0.051.

66. The piston of claim 40 wherein the ratio of the annular surface radius R3 to the diameter of the piston D1 and the ratio of the annular surface radius R4 to the diameter of the piston D1 are each greater than 0.0 and less than 0.1.

67. The piston of claim 40 wherein the distance between the co-center of the spherical surfaces RS1, RS2 and the point of intersection of a combustion chamber axis with a bottom plane of the combustion chamber is less than 0.28 the piston diameter D1.

68. The piston of claim 67 wherein the distance between the co-center of the spherical surfaces RS1, RS2 and the point of intersection of a combustion chamber axis with the bottom plane of the combustion chamber is preferably 0.073 D1.

69. The piston of claim 40 wherein the origin of a spherical surface RS3 is on a central axis of the combustion chamber.

70. The piston of claim 69 wherein the distance between the origin of the spherical surface RS3 and a point of intersection of the central axis of the combustion chamber with a bottom plane of the combustion chamber is greater than 0.75 the piston diameter D1 and less than 3.0 D1.

71. The piston of claim 70 wherein the distance between the origin of the spherical surface RS3 and the point of intersection of the central axis of the combustion chamber with the bottom plane of the combustion chamber is preferably 2.178 D1.

72. The piston of claim 40 wherein the origin of a spherical surface RS4 is on a combustion chamber central axis and the distance between the origin of the spherical surface RS4 and a point of intersection of the central axis of the combustion chamber with a top plane of the combustion chamber is the height H3 greater than 0.02 the piston diameter D1 and less than 0.42 D1.

73. The piston of claim 72 wherein the ratio of the height H3 to the diameter of the piston D1 is greater than 0.02 and less than 0.42.

74. The piston of claim 73 wherein the ratio of the height H3 to the diameter of the piston D1 is preferably substantially 0.051.

75. The piston of claim 40, the combustion chamber having a central axis, the combustion chamber central axis being coincident with a piston central axis.

76. The piston of claim 40, the combustion chamber having a central axis, the combustion chamber central axis being offset from a piston central axis.

77. The piston of claim 76, the combustion chamber having a central axis, the combustion chamber central axis being offset from the piston central axis less than a distance equal to 0.1 the piston diameter D1.

78. The piston of claim 40, the combustion chamber being formed free of flat surfaces.

79. A method of forming a combustion chamber for use in a piston of a diesel engine, comprising:

defining a combustion chamber in a crown of a piston, the piston having a central axis, the combustion chamber being formed by;

defining a combustion chamber elevated center portion;

defining the center portion at least in part by a portion of a convex sphere, the sphere having a radius,

defining a combustion chamber bottom margin in part by a concave spherical surface, the concave spherical surface having a radius; and

defining a plurality of combustion chamber spherical surfaces having smooth transitions between adjacent spherical surfaces, the spherical surfaces including at least the convex spherical center portion, the concave spherical bottom margin surface.

80. The method of claim 79 including defining the combustion chamber by a plurality of spherical surfaces and a plurality of annular surfaces.

81. The method of claim 80 including defining the combustion chamber by four spherical surfaces and adjoining annular surfaces.

82. The method of claim 79 including disposing the respective origins of the convex spherical center portion and the spherical lower sidewall surfaces co-centrically.

83. The method of claim 79 including forming the combustion chamber free of flat surfaces.

84. The method of claim 79 including displacing a combustion chamber central axis in a parallel relationship with a piston central axis.

85. The method of claim 79 including disposing a combustion chamber central axis co-linear with a piston central axis.