Exhaust manifold for internal combustion engine

• US 6,725,655 B2
• Filed: 11/28/2001
• Issued: 04/27/2004
• Est. Priority Date: 12/07/2000
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Mori, Kouji, Yoshirawa, Koudai, Hasegawa, Kazuya
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): TRAN, DIEM T
• Application Number:
  US09/994,667
• Publication Number:
  US 20020069643A1
• Time in Patent Office: 881 Days
• Field of Search: 603/21, 603/22, 603/23, 603/13, 603/24
• US Class Current: 60/323
• CPC Class Codes: F01N 13/008 Mounting or arrangement of exhaust sensors in or on exhaust apparatus sensor arrangements for engine control F02D41/1439
• CPC Class Codes: F01N 13/08 Other arrangements or adaptations of exhaust conduits pipes, joints or supports therefor in general F16L; collecting or removing exhaust gases of vehicle engines in workshops B08B15/00, on highways E01C1/005
• CPC Class Codes: F01N 13/10 of exhaust manifolds with cooling jacket F01N3/046
• CPC Class Codes: F02D 41/1439 characterised by the position of the sensor
• CPC Class Codes: F02D 41/1441 Plural sensors
• CPC Class Codes: F02D 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen

Abstract

An exhaust manifold provides improved output by suppressing exhaust interference between cylinders at the exhaust manifold. An air-fuel ratio sensor is installed in position where it can uniformly detect the exhaust gas of each cylinder. The exhaust manifold has a plurality of exhaust tubes, one per cylinder, that connect with a collector case. Each of exhaust tubes has a linear portion located directly above the section where it merges with the collector case. The exhaust tubes are connected to the collector case such that the center axes of the linear portions intersect at intersection point inside the collector case or downstream thereof. The air-fuel ratio sensor is arranged such that its detecting part is positioned in the vicinity of the intersection point. Depending upon whether the exhaust tubes of cylinders have firing orders that are successive or not determines whether the exhaust tubes are slanted or parallel with respect to each other.

Claims

1. An exhaust manifold of an internal combustion engine having a first, second, third and fourth cylinders, the exhaust manifold comprising:

a collector case having an upstream end and a downstream end, the downstream end being attached to a catalyst unit;

a first exhaust tube having a first inlet end, a first outlet end and a first linear portion, the first exhaust tube being configured and arranged to receive an exhaust gas only from the first cylinder, the first inlet end being configured and arranged to be connected to an exhaust port of the first cylinder of the internal combustion engine, the first outlet end being connected to the upstream end of the collector case, the first linear portion being located directly above the first outlet end;

a second exhaust tube having a second inlet end, a second outlet end and a second linear portion, the second exhaust tube being configured and arranged to receive an exhaust gas only from the second cylinder, the second inlet end being configured and arranged to be connected to an exhaust port of the second cylinder of the internal combustion engine, the second outlet end being connected to the upstream end of the collector case, the second linear portion being located directly above the second outlet end;

a third exhaust tube having a third inlet end, a third outlet end and a third linear portion, the third exhaust tube being configured and arranged to receive an exhaust gas only from the third cylinder, the third inlet end being configured and arranged to be connected to an exhaust port of the third cylinder of the internal combustion engine, the third outlet end being connected to the upstream end of the collector case, the third linear portion being located directly above the third outlet end, a center axis of the third linear portion of the third exhaust tube being substantially parallel with a center axis of the first linear portion of the first exhaust tube and intersecting a center axis of the second linear portion of the second exhaust tube at a first intersection point inside the collector case or downstream thereof; and

a fourth exhaust tube having a fourth inlet end, a fourth outlet end and a fourth linear portion, the fourth exhaust tube being configured and arranged to receive an exhaust gas only from the fourth cylinder, the fourth inlet end being configured and arranged to be connected to an exhaust port of the fourth cylinder of the internal combustion engine, the fourth outlet end being connected to the upstream end of the collector case, the fourth linear portion being located directly above the fourth outlet end, a center axis of the fourth linear portion of the fourth exhaust tube being substantially parallel with the center axis of the second linear portion of the second exhaust tube and intersecting the center axis of the first linear portion of the first exhaust tube at a second intersection point inside the collector case or downstream thereof.

2. The exhaust manifold as recited in claim 1, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the third cylinder are successive and firing orders of the second cylinder and the fourth cylinder are successive.

3. The exhaust manifold as recited in claim 2, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the fourth cylinders are not successive and firing orders of the third cylinder and the second cylinder are not successive.

4. The exhaust manifold as recited in claim 1, wherein

the collector case has an air-fuel ratio sensor installed inside the collector case with a detecting part of the air-fuel ratio sensor being positioned adjacent the first and second intersection points.

5. The exhaust manifold as recited in claim 4, wherein

the detecting part of the air-fuel ratio sensor has a center axis;

and

the center axes of the first and fourth linear portions of the first and fourth exhaust tubes, respectively, and the center axis of the air fuel ratio sensor form angles therebetween with an angle of one of the first and fourth linear portions that is farther from the air-fuel ratio sensor being closer to perpendicular than an angle of the other of the first and fourth linear portions that is closer to the air-fuel ratio sensor.

6. The exhaust manifold as recited in claim 1, wherein

the collector case has an air fuel ratio sensor located in the collector case, and at least some of the first, second, third and fourth outlet ends open into the collector case at different distances from the air fuel ratio sensor as measured in an air stream direction of each of the first, second, third and fourth exhaust tubes into the collector case.

7. The exhaust manifold as recited in claims 6, wherein

at least one of the first, second, third and fourth outlet ends of the first, second, third and fourth exhaust tubes, respectively, that is closer to the air-fuel ratio sensor, as measured in a transverse direction to the air stream directions, is spaced farther upstream from the air-fuel ratio sensor as measured in a longitudinal direction of the air stream directions.

8. The exhaust manifold as recited in claim 1, wherein

the catalyst unit includes a front end face connected to the downstream end of the collector case, the front end face being angled with respect to a reference plane which is perpendicular to an axial line that represents a center line of the center axes of the first, second, third and fourth linear portions of the first, second, third and fourth exhaust tubes, respectively.

9. The exhaust manifold as recited in claim 8, wherein

the catalyst unit has a center axis that is offset from the centerline of the center axes of the first, second, third and fourth linear portions of the first, second, third and fourth exhaust tubes, respectively;

and

the front end face of the catalyst unit is angled such that distances of the upstream end of the collector case to the front end face of the catalyst unit becomes longer across the front end face of the catalyst unit.

10. The exhaust manifold as recited in claim 1, wherein

the first, second, third and fourth linear portions of the first, second, third and fourth exhaust tubes, respectively, have substantially fan-shaped cross sectional shapes that are substantially equal in size where the first, second, third and fourth exhaust tubes are connected to the collector case.

11. An exhaust manifold of an internal combustion engine having a first, second, third and fourth cylinders, the exhaust manifold comprising:

a collector case having an upstream end and a downstream end, the downstream end being attached to a catalyst unit;

a first exhaust tube having a first inlet end, a first outlet end and a first linear portion, the first inlet end being configured and arranged to be connected to an exhaust port of the first cylinder of the internal combustion engine, the first outlet end being connected to the upstream end of the collector case, the first linear portion being located directly above the first outlet end;

a second exhaust tube having a second inlet end, a second outlet end and a second linear portion, the second inlet end being configured and arranged to be connected to an exhaust port of the second cylinder of the internal combustion engine, the second outlet end being connected to the upstream end of the collector case, the second linear portion being located directly above the second outlet end;

a third exhaust tube having a third inlet end, a third outlet end and a third linear portion, the third inlet end being configured and arranged to be connected to an exhaust port of the third cylinder of the internal combustion engine, the third outlet end being connected to the upstream end of the collector case, the third linear portion being located directly above the third outlet end, a center axis of the third linear portion of the third exhaust tube being substantially parallel with a center axis of the first linear portion of the first exhaust tube and intersecting a center axis of the second linear portion of the second exhaust tube at a first intersection point inside the collector case or downstream thereof; and

a fourth exhaust tube having a fourth inlet end, a fourth outlet end and a fourth linear portion, the fourth inlet end being configured and arranged to be connected to an exhaust port of the fourth cylinder of the internal combustion engine, the fourth outlet end being connected to the upstream end of the collector case, the fourth linear portion being located directly above the fourth outlet end, a center axis of the fourth linear portion of the fourth exhaust tube being substantially parallel with the center axis of the second linear portion of the second exhaust tube and intersecting the center axis of the first linear portion of the first exhaust tube at a second intersection point inside the collector case or downstream thereof,

the first, second, third and fourth outlet ends and the collector case being configured and arranged to create a vortex of exhaust gases above the catalyst unit.

12. The exhaust manifold as recited in claim 11, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the third cylinder are successive and firing orders of the second cylinder and the fourth cylinder are successive.

13. The exhaust manifold as recited in claim 12, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the fourth cylinders are not successive and firing orders of the third cylinder and the second cylinder are not successive.

14. The exhaust manifold as recited in claim 11, wherein

the collector case has an air-fuel ratio sensor installed inside the collector case with a detecting part of the air-fuel ratio sensor being positioned adjacent the first and second intersection points.

15. The exhaust manifold as recited in claim 14, wherein

the detecting part of the air-fuel ratio sensor has a center axis;

and

the center axes of the first and fourth linear portions of the first and fourth exhaust tubes, respectively, and the center axis of the air fuel ratio sensor form angles therebetween with an angle of one of the first and fourth linear portions that is farther from the air-fuel ratio sensor being closer to perpendicular than an angle of the other of the first and fourth linear portions that is closer to the air-fuel ratio sensor.

16. An exhaust manifold of an internal combustion engine having a first, second, third and fourth cylinders, the exhaust manifold comprising:

a collector case having an upstream end and a downstream end, the downstream end being attached to a catalyst unit;

a first exhaust tube having a first inlet end, a first outlet end and a first linear portion, the first inlet end being arranged to be connected to an exhaust port of the first cylinder of the internal combustion engine, the first outlet end being connected to the upstream end of the collector case, the first linear portion being located directly above the first outlet end;

a second exhaust tube having a second inlet end, a second outlet end and a second linear portion, the second inlet end being arranged to be connected to an exhaust port of the second cylinder of the internal combustion engine, the second outlet end being connected to the upstream end of the collector case, the second linear portion being located directly above the second outlet end;

a third exhaust tube having a third inlet end, a third outlet end and a third linear portion, the third inlet end being arranged to be connected to an exhaust port of the third cylinder of the internal combustion engine, the third outlet end being connected to the upstream end of the collector case, the third linear portion being located directly above the third outlet end, a center axis of the third linear portion of the third exhaust tube being substantially parallel with a center axis of the first linear portion of the first exhaust tube and intersecting a center axis of the second linear portion of the second exhaust tube at a first intersection point inside the collector case or downstream thereof; and

a fourth exhaust tube having a fourth inlet end, a fourth outlet end and a fourth linear portion, the fourth inlet end being arranged to be connected to an exhaust port of the fourth cylinder of the internal combustion engine, the fourth outlet end being connected to the upstream end of the collector case, the fourth linear portion being located directly above the fourth outlet end, a center axis of the fourth linear portion of the fourth exhaust tube being substantially parallel with the center axis of the second linear portion of the second exhaust tube and intersecting the center axis of the first linear portion of the first exhaust tube at a second intersection point inside the collector case or downstream thereof,

the first, second, third and fourth outlet ends being configured and arranged relative to the upstream end of the collector case such that the first and second intersection points are located adjacent a side wall of the collector case.

17. The exhaust manifold as recited in claim 16, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the third cylinder are successive and firing orders of the second cylinder and the fourth cylinder are successive.

18. The exhaust manifold as recited in claim 17, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the fourth cylinders are not successive and firing orders of the third cylinder and the second cylinder are not successive.

19. An exhaust manifold of an internal combustion engine having a first, second, third and fourth cylinders, the exhaust manifold comprising:

a collector case having an upstream end and a downstream end, the downstream end being attached to a catalyst unit;

a first exhaust tube having a first inlet end, a first outlet end and a first linear portion, the first inlet end being arranged to be connected to an exhaust port of the first cylinder of the internal combustion engine, the first outlet end being connected to the upstream end of the collector case, the first linear portion being located directly above the first outlet end;

a second exhaust tube having a second inlet end, a second outlet end and a second linear portion, the second inlet end being arranged to be connected to an exhaust port of the second cylinder of the internal combustion engine, the second outlet end being connected to the upstream end of the collector case, the second linear portion being located directly above the second outlet end;

a third exhaust tube having a third inlet end, a third outlet end and a third linear portion, the third inlet end being arranged to be connected to an exhaust port of the third cylinder of the internal combustion engine, the third outlet end being connected to the upstream end of the collector case, the third linear portion being located directly above the third outlet end, a center axis of the third linear portion of the third exhaust tube being substantially parallel with a center axis of the first linear portion of the first exhaust tube and intersecting a center axis of the second linear portion of the second exhaust tube at a first intersection point inside the collector case or downstream thereof; and

a fourth exhaust tube having a fourth inlet end, a fourth outlet end and a fourth linear portion, the fourth inlet end being arranged to be connected to an exhaust port of the fourth cylinder of the internal combustion engine, the fourth outlet end being connected to the upstream end of the collector case, the fourth linear portion being located directly above the fourth outlet end, a center axis of the fourth linear portion of the fourth exhaust tube being substantially parallel with the center axis of the second linear portion of the second exhaust tube and intersecting the center axis of the first linear portion of the first exhaust tube at a second intersection point inside the collector case or downstream thereof,

the collector case having an air-fuel ratio sensor installed inside the collector case with a detecting part of the air-fuel ratio sensor being positioned adjacent a midpoint of the first and second intersection points.

20. The exhaust manifold as recited in claim 19, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the third cylinder are successive and firing orders of the second cylinder and the fourth cylinder are successive.

21. The exhaust manifold as recited in claim 20, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the fourth cylinders are not successive and firing orders of the third cylinder and the second cylinder are not successive.

22. An exhaust manifold of an internal combustion engine having a first, second, third and fourth exhaust ports connected to a first, second, third and fourth cylinders, respectively, the exhaust manifold comprising:

a collector case having a substantially partial spherical upstream end and a downstream end, the downstream end being attached to a catalyst unit;

a first exhaust tube having a first inlet end, a first outlet end and a first linear portion, the first inlet end being configured and arranged to be connected to an exhaust port of the first cylinder of the internal combustion engine, the first outlet end being connected to the substantially partial spherical upstream end of the collector case to avoid disruption of exhaust flow in the collector case, the first linear portion being located directly above the first outlet end;

a second exhaust tube having a second inlet end, a second outlet end and a second linear portion, the second inlet end being configured and arranged to be connected to an exhaust port of the second cylinder of the internal combustion engine, the second outlet end being connected to the substantially partial spherical upstream end of the collector case to avoid disruption of exhaust flow in the collector case, the second linear portion being located directly above the second outlet end;

a third exhaust tube having a third inlet end, a third outlet end and a third linear portion, the third inlet end being configured and arranged to be connected to an exhaust port of the third cylinder of the internal combustion engine, the third outlet end being connected to the substantially partial spherical upstream end of the collector case to avoid disruption of exhaust flow in the collector case, the third linear portion being located directly above the third outlet end, a center axis of the third linear portion of the third exhaust tube being substantially parallel with a center axis of the first linear portion of the first exhaust tube and intersecting a center axis of the second linear portion of the second exhaust tube at a first intersection point inside the collector case or downstream thereof; and

a fourth exhaust tube having a fourth inlet end, a fourth outlet end and a fourth linear portion, the fourth inlet end being configured and arranged to be connected to an exhaust port of the fourth cylinder of the internal combustion engine, the fourth outlet end being connected to the substantially partial spherical upstream end of the collector case to avoid disruption of exhaust flow in the collector case, the fourth linear portion being located directly above the fourth outlet end, a center axis of the fourth linear portion of the fourth exhaust tube being substantially parallel with the center axis of the second linear portion of the second exhaust tube and intersecting the center axis of the first linear portion of the first exhaust tube at a second intersection point inside the collector case or downstream thereof.

23. The exhaust manifold as recited in claim 22, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the third cylinder are successive and firing orders of the second cylinder and the fourth cylinder are successive.

24. The exhaust manifold as recited in claim 23, wherein

the first, second, third and fourth inlet ends of the first, second, third and fourth exhaust tubes, respectively, are arranged relative to each other such that firing orders of the first cylinder and the fourth cylinders are not successive and firing orders of the third cylinder and the second cylinder are not successive.

25. An exhaust manifold of an internal combustion engine having a plurality of cylinders, the exhaust manifold comprising:

a collector case having an upstream end and a downstream end, the downstream end being attached to a catalyst unit;

a first exhaust tube having a first inlet end, a first outlet end and a first linear portion, the first inlet end being configured and arranged to be connected to an exhaust port of one of the cylinders, the first outlet end being connected to the upstream end of the collector case, the first linear portion being located directly above the first outlet end;

a second exhaust tube having a second inlet end, a second outlet end and a second linear portion, the second inlet end being configured and arranged to be connected to an exhaust port of one of the cylinders, the second outlet end being connected to the upstream end of the collector case, the second linear portion being located directly above the second outlet end, a center axis of the second linear portion of the second exhaust tube intersecting a center axis of the first linear portion of the first exhaust tube at an intersection point inside the collector case or downstream thereof; and

a third exhaust tube having a third inlet end, a third outlet end and a third linear portion, the third inlet end being configured and arranged to be connected to an exhaust port of one of the cylinders, the third outlet end being connected to the upstream end of the collector case, the third linear portion being located directly above the third outlet end, a center axis of the third linear portion of the third exhaust tube intersecting the center axis of the first linear portion of the first exhaust tube at the intersection point,

the first, second and third outlet ends and the collector case being configured and arranged to create a vortex of exhaust gases above the catalyst unit,

the collector case having an air fuel ratio sensor located in the collector case, and

at least some of the first, second and third outlet ends opening into the collector case at different distances from the air fuel ratio sensor as measured in an air stream direction of each of the first, second and third exhaust tubes into the collector case.

26. The exhaust manifold as recited in claims 25, wherein

at least one of the first, second and third outlet ends of the first, second and third exhaust tubes, respectively, that is closer to the air-fuel ratio sensor, as measured in a transverse direction to the air stream directions, is spaced farther upstream from the air-fuel ratio sensor as measured in a longitudinal direction of the air stream directions.

27. An exhaust manifold of an internal combustion engine having a plurality of cylinders, the exhaust manifold comprising:

a collector case having a substantially partial spherical upstream end and a downstream end, the downstream end being attached to a catalyst unit;

a first exhaust tube having a first inlet end, a first outlet end and a first linear portion, the first inlet end being configured and arranged to be connected to an exhaust port of one of the cylinders, the first outlet end being connected to the substantially partial spherical upstream end of the collector case to avoid disruption of exhaust flow in the collector case, the first linear portion being located directly above the first outlet end;

a second exhaust tube having a second inlet end, a second outlet end and a second linear portion, the second inlet end being configured and arranged to be connected to an exhaust port of one of the cylinders, the second outlet end being connected to the substantially partial spherical upstream end of the collector case to avoid disruption of exhaust flow in the collector case, the second linear portion being located directly above the second outlet end, a center axis of the second linear portion of the second exhaust tube intersecting a center axis of the first linear portion of the first exhaust tube at an intersection point inside the collector case or downstream thereof;

a third exhaust tube having a third inlet end, a third outlet end and a third linear portion, the third inlet end being configured and arranged to be connected to an exhaust port of one of the cylinders, the third outlet end being connected to the substantially partial spherical upstream end of the collector case to avoid disruption of exhaust flow in the collector case, the third linear portion being located directly above the third outlet end, a center axis of the third linear portion of the third exhaust tube intersecting the center axis of the first linear portion of the first exhaust tube at the intersection point.

28. The exhaust manifold as recited in claims 27, further comprising

a fourth exhaust tube having a fourth inlet end, a fourth outlet end and a fourth linear portion, the fourth inlet end being configured and arranged to be connected to an exhaust port of one of the cylinders, the fourth outlet end being connected to the substantially partial spherical upstream end of the collector case to avoid disruption of exhaust flow in the collector case, the fourth linear portion being located directly above the fourth outlet end, a center axis of the fourth linear portion of the fourth exhaust tube intersecting the center axis of the first linear portion of the first exhaust tube at the intersection point.

29. The exhaust manifold as recited in claim 28, wherein,

the collector case has an air-fuel ratio sensor installed inside the collector case with a detecting part of the air-fuel ratio sensor being positioned adjacent the intersection point.