| 摘要 |
PURPOSE:To make it possible to optimize the air fuel ratio of each cylinder at a low cost by arranging a plurality of detecting parts which detect the air fuel ratio at the main body of a sensor. CONSTITUTION:First and second oxygen concentration detecting parts 12 and 13 are attached to an oxygen sensor 11 as an air fuel ratio sensor so that a specified gap is provided with an insulating member 14. In the sensor 11 having such a constitution, e.g., the detecting part 12 is provided at a first branch part 18A which is communicated to cylinders No.1 and No.4 at the assembled part of exhaust manifolds 18. Meanwhile, the detecting part 13 is provided at a second branch part 18B which is communicated to cylinders No.2 and No.3. A sensor main body 19 is attached to the outer wall of the manifold 18. In this constitution, oxygen concentrations (air fuel ratio) in exhausts from the cylinders No.1 and No.4 and the cylinders No.2 and No.3 can be individually detected highly accurately. Therefore, the air fuel ratio of each cylinder can be controlled optimally, and the variations in air fuel ratios among the cylinders can be decreased. |
