STRUCTURE FOR ATTACHING AN EXHAUST GAS SENSOR OF AN INTERNAL COMBUSTION ENGINE

A cylinder head 42 of an internal combustion engine 4 is formed therein with a first exhaust port section 72A having an upstream inlet 72Aa opened and closed by a first exhaust valve 74A, a second exhaust port section 72B having an upstream inlet 72Ba opened and closed by a second exhaust valve 74B, and a collective exhaust port section 72C into which the first and second exhaust port sections 72A and 72B merge at downstream ends thereof. In a fixing structure for an exhaust gas sensor 7, the sensor 7 is fixed to an inner wall of the collective exhaust port section 72C with its sensing tip 7a in the port section 72C. An exhaust gas guide part 80 is formed, at a position upstream of the sensor 7, on an internal wall 76A of the port section 72C, opposite the internal wall to which the sensor 7 is fixed, so as to bulge out to guide exhaust gas toward the sensor 7, whereby exhaust gas is effectively intermixed and directed to the sensor 7 with resultant increased sensing accuracy.