Exhaust structure of internal combustion engine

An exhaust structure is installed in an internal combustion engine having an exhaust passage that communicates between an exhaust port of a combustion chamber and an exhaust pipe, the exhaust structure comprising:

• a heat insulating component covering at least a portion of an inner wall of the exhaust port, wherein the heat insulating component comprises:
• a first abutting portion disposed at a first side of the heat insulating component at a combustion chamber side and abutting the inner wall of the exhaust port;
• a second abutting portion disposed at a second side of the heat insulating component at an exhaust pipe side and abutting the inner wall of the exhaust port;
• a middle section disposed between the first side and the second side of the heat insulating component, wherein a gap is formed between the middle section of the heat insulating component and the inner wall of the exhaust port;
• and
• a bent portion connecting the middle section and the first abutting portion and bending toward the inner wall of the exhaust port from the middle section,
• wherein a distance between the bent portion and the inner wall in a radial direction of the heat insulating component changes gradually in an axial direction of the heat insulating component,
• wherein the bent portion is bent such that the first abutting portion is disposed closer to the exhaust pipe side than a connecting point connecting the middle section and the bent portion.