Exhaust manifold of a four-cylinder engine

摘要

The present invention relates to an engine (1) comprising at least four cylinders (#1,#2,#3,#4), an exhaust manifold (2) mounted to a cylinder head of the engine (1), and at least four exhaust manifold branches (B1,B2,B3,B4) included in the exhaust manifold (2) and arranged to each cylinder (#1,#2,#3,#4) wherein two exhaust manifold branches (B2,B3) of two cylinders (#2,#3) that are not fired in succession are convergent at a first convergence point to form a first convergent exhaust manifold branch (W2), two exhaust manifold branches (B1,B4) of another two cylinders (#1,#4) that are not fired in succession are convergent at a second convergence point to form a second convergent exhaust manifold branch (W1), the exhaust flow path between the cylinder head and the first convergence point is substantially shorter than the exhaust flow path between the cylinder head and the second convergence point, and the first convergent exhaust manifold branch (W2) and the second convergent exhaust manifold branch (W1) are thereafter made convergent at a third convergence point just downstream of the second convergence point.