Exhaust pipe structure for in-line four-cylinder internal combustion engine

Abstract

An exhaust pipe structure for an in-line four-cylinder internal combustion engine includes: an in-line four-cylinder internal combustion engine; four exhaust pipes connected with respective exhaust ports in respective cylinders of the internal combustion engine; and a converging exhaust pipe connected with a converging portion at which downstream ends of all the exhaust pipes converge. In this exhaust pipe structure, the exhaust pipes are each configured as a dual pipe including an outer pipe and an inner pipe disposed inside the outer pipe. At the converging portion, the four exhaust pipes are arrayed linearly in parallel with each other, and the outer pipes of adjacent ones of the exhaust pipes are directly welded with each other at the downstream ends.