INTAKE OXYGEN CONCENTRATION SENSOR DIAGNOSTIC SYSTEM FOR INTERNAL COMBUSTION ENGINE AND INTAKE OXYGEN CONCENTRATION SENSOR DIAGNOSTIC METHOD FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To provide an intake oxygen concentration sensor diagnostic system for an internal combustion engine and an intake oxygen concentration sensor diagnostic method for the internal combustion engine capable of more accurately diagnosing an intake oxygen concentration sensor checking whether it is normal.SOLUTION: A system 100 includes an internal combustion engine 1, an intake passage 11, an exhaust passage 21, a supercharger 30, an EGR device 40, an intake oxygen concentration sensor 16 and a controller 80. The controller 80 makes a first determination when the operating state of the internal combustion engine 1 is in a first operating region set in an EGR stop region. When a first flag indicating the determination result of the first determination is in an ON state, the intake oxygen concentration sensor 16 is diagnosed as normal.SELECTED DRAWING: Figure 1 【課題】吸気酸素濃度センサが正常であるか否かをより正確に診断することができる内燃機関の吸気酸素濃度センサ診断システム及び内燃機関の吸気酸素濃度センサ診断方法を提供する。【解決手段】システム１００は、内燃機関１と、吸気通路１１と、排気通路２１と、過給機３０と、ＥＧＲ装置４０と、吸気酸素濃度センサ１６と、コントローラ８０と、を備える。コントローラ８０は、内燃機関１の運転状態が、ＥＧＲ停止領域に設定された第１の運転領域にある場合に、第１の判定を行う。そして、第１の判定の判定結果を示す第１のフラグがＯＮである場合に、吸気酸素濃度センサ１６は正常であると診断する。【選択図】図１