Patent ID: 6725655
Filing Date: 2004-04-27
Classification: F01N,F02D

Abstract:
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.