Exhaust passage structure for internal combustion engine

Abstract

Inner exhaust passages (inner exhaust ports 4B and 4C) are provided with three or more curves 41 through 43 that extend toward downstream sides of exhaust gas flow and alternately curve to one side and the other side in directions of a cylinder center line C.

Description

technical field [0001] The present invention relates to an exhaust passage structure for an internal combustion engine, and more particularly to the shape of passages respectively communicating with a plurality of cylinders. Background technique [0002] In a multi-cylinder internal combustion engine (hereinafter referred to as an engine) mounted on a vehicle, the exhaust passages respectively communicating with the cylinders on the outer side in the cylinder bank direction are largely curved toward the inner side and have a certain distance to the collecting portion. length, while the other exhaust passages communicating with the cylinders on the inner side in the cylinder bank direction extend approximately linearly when viewed in the direction of the cylinder centerline and tend to be shortened compared with the outer exhaust passages. [0003] Therefore, in the inner exhaust passage, the heat dissipation characteristics are relatively deteriorated, and the durability, re...

AI Technical Summary

Problems solved by technology

In this case, the increase in the size of the exhaust manifold directly leads to an increase in the size and weight of the cylinder head

[0010] In addition, when the heat dissipation characteristics of the exhaust port in the cylinder head need to be improved, the volume or flow rate of the coolant in the water jacket may tend to increase

In this regard, the disadvantage that may arise is an increase in the overall weight and a possible increase in the load of the water pumps for supplying the coolant

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