Patent ID: 6702062
Filing Date: 2004-03-09
Classification: F01N

Abstract:
A structure of exhaust system for an in-line multiple cylinder engine having a cylinder block and a cylinder head to be mounted on a vehicle body, which comprises an exhaust manifold connected to said cylinder head and an exhaust pipe supported to said vehicle body and connected to said exhaust manifold, said exhaust manifold comprising:a plurality of single-shell discrete exhaust pipes that are connected to exhaust ports formed in said cylinder head, respectively; a double-shell collective chambered pipe joined to said single-shell discrete exhaust pipes, said collective chambered pipe comprising an internal pipe shell into which exhaust gas streams passing through said single-shell discrete exhaust pipes are introduced and merge together and an external pipe shell surrounding said internal pipe shell with a cylindrical space left between said internal pipe shell; and a spherical joint connecting said collective chambered pipe to said exhaust pipe so as to allow relative movement between said exhaust manifold and said exhaust pipe; a fitting flange connected to upstream ends of said single-shell discrete exhaust pipes through which said exhaust manifold is fixedly attached to said cylinder head; a heat guide member extending toward far from said in-line multiple cylinder engine so as to conduct and release exhaust heat from said space toward far from said in-line multiple cylinder engine; and a heat insulation shell made up of upper and lower mating shell halves for covering said exhaust manifold comprising at least single-shell discrete exhaust pipes and said collective chambered pipe, each said shell half being connected to at least one of said single-shell discrete exhaust pipes and said collective chambered pipe with a specified distance of space provided between said fitting flange of said discrete exhaust pipes and an upstream end of said heat insulation shell; wherein each said single-shell discrete exhaust pipe a bent portion extending from said exhaust port and a straight portion continuously extending from said bent portion to said collective chambered pipe, said bent portions of said single-shell discrete exhaust pipes being bent toward a center of a straight row of cylinders so as to lay said straight portions of said single-shell discrete exhaust pipes nearly parallel to one another and said single-shell discrete exhaust pipes and said collective exhaust pipe are at least partly joined to each other at a height of an interface between said cylinder block and said cylinder head.