Abstract: A heat insulating structure for an exhaust junction pipe to be disposed in an area in which exhaust gas passages having different respective lengths are merged together comprises a first heat insulation portion that covers and provides heat insulation for at least a portion of one branch part of branch parts that are branched in the exhaust junction pipe; the one branch part forms one exhaust gas passage in a not-yet-merged state of the exhaust gas passages, and forms the one exhaust gas passage having a short length.

Abstract: A heat insulating structure for an exhaust junction pipe to be disposed in an area in which exhaust gas passages having different respective lengths are merged together comprises a first heat insulation portion that covers and provides heat insulation for at least a portion of one branch part of branch parts that are branched in the exhaust junction pipe; the one branch part forms one exhaust gas passage in a not-yet-merged state of the exhaust gas passages, and forms the one exhaust gas passage having a short length.

Abstract: A secondary air supply system for an internal combustion engine includes: a cylinder head of the internal combustion engine having a plurality of exhaust holes and a plurality of supply holes formed thereon; a supply path communicating the exhaust holes and the supply holes so as to supply secondary air into the supply holes; an exhaust manifold attached to the cylinder head, and provided with a flange having a plurality of communication holes penetrating the flange; a lower shell including connection holes respectively corresponding to the communication holes, the lower shell being secured to the flange such that the communication holes and the connection holes are aligned; and an upper shell combined with the lower shell so as to form the supply path, communicated with the plurality of connection holes, between the lower shell and the upper shell.

Abstract: A secondary air supply system for an internal combustion engine includes: a cylinder head of the internal combustion engine having a plurality of exhaust holes and a plurality of supply holes formed thereon; a supply path communicating the exhaust holes and the supply holes so as to supply secondary air into the supply holes; an exhaust manifold attached to the cylinder head, and provided with a flange having a plurality of communication holes penetrating the flange; a lower shell including connection holes respectively corresponding to the communication holes, the lower shell being secured to the flange such that the communication holes and the connection holes are aligned; and an upper shell combined with the lower shell so as to form the supply path, communicated with the plurality of connection holes, between the lower shell and the upper shell.

Abstract: In a secondary air supplying structure of an internal combustion engine, extending portions protruding upward are arranged in the number corresponding to the number of cylinders. Extending portions are each provided with a secondary air distribution path. To a surface of extending portion to which secondary air supplying pipe abuts, a seating face that conforms to the outer shape of secondary air supplying pipe is formed. Secondary air distributing path is arranged to be inclined downwardly from secondary air supplying pipe side toward the cylinder exhaust system of cylinder head. Thus, it is possible to provide the secondary air supplying structure of an internal combustion engine that can attain an improvement in the strength of the secondary air supplying path, reduction of the space, rust prevention, reduced costs, reduced weight, simplified structure, and prevention of thermal damage to other components.

Abstract: In a secondary air supplying structure of an internal combustion engine, extending portions protruding upward are arranged in the number corresponding to the number of cylinders. Extending portions are each provided with a secondary air distribution path. To a surface of extending portion to which secondary air supplying pipe abuts, a seating face that conforms to the outer shape of secondary air supplying pipe is formed. Secondary air distributing path is arranged to be inclined downwardly from secondary air supplying pipe side toward the cylinder exhaust system of cylinder head. Thus, it is possible to provide the secondary air supplying structure of an internal combustion engine that can attain an improvement in the strength of the secondary air supplying path, reduction of the space, rust prevention, reduced costs, reduced weight, simplified structure, and prevention of thermal damage to other components.