Exhaust manifold for four-cylinder engine

• US 20030167759A1
• Filed: 03/06/2003
• Published: 09/11/2003
• Est. Priority Date: 03/08/2002
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nishizawa, Kimiyoshi, Ashida, Masaaki
• Granted Patent: US 6,962,049 B2
• Time in Patent Office: Days
• US Class Current: 60/323
• 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: F01N 3/28 Construction of catalytic reactors
• CPC Class Codes: F02B 27/04 in exhaust systems only, e.g. for sucking-off combustion gases
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

In an exhaust manifold of a four-cylinder engine four cylinders of which line up in order of cylinder #1, cylinder #2, cylinder #3 and cylinder #4, temperature rise performance of a manifold catalyst improves by shortening a total length of the exhaust manifold while preventing exhaust gas interference between the cylinders. Therefore, an exhaust manifold branch of cylinder #1 and an exhaust manifold branch of cylinder #4 in outward sides of the engine that are not fired in succession are made convergent with its convergence angle θ1 being equal to or below 20 degrees to form a first convergent exhaust manifold branch and an exhaust manifold branch of cylinder #2 and an exhaust manifold branch of cylinder #3 between the cylinder #1 and cylinder #4 that are not fired in succession are made convergent at a minimum distance having a laterally projected shape to form a second convergent exhaust manifold branch. The first and the second convergent exhaust manifold branches are thereafter convergent at a convergence angle θ3 from 0 degrees to 20 degrees.

Claims

1. An engine comprising:

four cylinders;

an exhaust manifold mounted to a cylinder head of the engine; and

four exhaust manifold branches included in the exhaust manifold and arranged to each cylinder, wherein

two exhaust manifold branches of two cylinders that are not fired in succession are convergent at a convergence angle equal to or below 20 degrees to form a first convergent exhaust manifold branch, two exhaust manifold branches of another two cylinders that are not fired in succession are convergent at a convergence angle equal to or below 20 degrees branch to form a second convergent exhaust manifold branch, and the first convergent manifold e second convergent exhaust manifold branch are thereafter made convergent.

2. An engine according to claim 1, wherein

the first convergent exhaust manifold branch and the second convergent exhaust manifold branch are convergent at a convergence angle equal to or below 20 degrees.

3. An engine according to claim 1, wherein

the four cylinders line up in order of cylinder #1, cylinder #2, cylinder #3, and cylinder #4, the four cylinders being fired in order of cylinder #1, cylinder #3, cylinder #4, and cylinder #2,

the two exhaust manifold branches of the cylinder #1 and the cylinder #4 arranged at both ends in a cylinder-in-line direction of the engine are convergent, and

the two exhaust manifold branches of the cylinder #2 and the cylinder #3 arranged between the cylinder #1 and the cylinder #4 in the cylinder-in-line direction of the engine are convergent.

4. An engine according to claim 3, wherein

the second convergent exhaust manifold branch is formed such that the two exhaust manifold branches of the cylinder #2 and the cylinder #3 are projected toward each other and substantially along the cylinder-in-line direction, and are thereafter convergent.

9. An engine according to claim 1, further comprising:

an exhaust valve disposed in a combustion chamber of the engine that controls an exhaust gas from the combustion chamber wherein

an exhaust valve opening timing of the exhaust valve is set in the range of from 30 degrees before bottom dead center to the bottom dead center.

5. An engine comprising:

four cylinders that line up in order of cylinder #1, cylinder #2, cylinder #3, and cylinder #4;

an exhaust manifold mounted to a cylinder head of the engine; and

four exhaust manifold branches included in the exhaust manifold and arranged to each cylinder, wherein

the four cylinders are fired in order of cylinder #1, cylinder #3, cylinder #4, and cylinder #2,

two exhaust manifold branches of the cylinder #1 and the cylinder #4 are convergent to form a first convergent exhaust manifold branch,

two exhaust manifold branches of the cylinder #2 and the cylinder #3 are convergent to form a second convergent exhaust manifold branch,

the first convergent exhaust manifold branch and the second convergent exhaust manifold branch are thereafter made convergent, and

a convergence position of the second convergent exhaust manifold branch is placed upstream of a convergence position of the first convergent exhaust manifold branch.

6. An engine according to claim 5, wherein

the second convergent exhaust branch is formed of one straight pipe.

7. An engine according to claim 5, wherein

the second convergent exhaust manifold branch is formed such that the two exhaust manifold branches of the cylinder #2 and the cylinder #3 are projected toward each other and substantially along a cylinder-in-line direction, and are thereafter convergent.

8. An engine according to claim 5, wherein

a convergence angle of the first convergent exhaust manifold branch, as well as a convergence angle of the second convergent exhaust manifold branch are respectively equal to or below 20 degrees, and

a convergence angle of the first and the second convergent exhaust manifold branches is equal to or below 20 degrees.

10. An engine according to claim 5, further comprising:

an exhaust valve disposed in a combustion chamber of the engine that controls an exhaust gas from the combustion chamber wherein

an exhaust valve opening timing of the exhaust valve is set in the range of from 30 degrees before bottom dead center to the bottom dead center.