| 摘要 |
PURPOSE:In an engine having a controller for deciding the number of operative cylinders according to the load level, to properly control the number of operative cylinders in low load level operation of an engine by subjecting the exhaust gas to a ternary catalyser and temporarily interrupting the feedback of the air-fuel ratio control. CONSTITUTION:The cylinders #1-#6 of a multicylinder engine having fuel injection nozzles 10a-10f are grouped into a first group (#1-#3) connected to an exhaust manifold 2a and a second group (#4-#6) connected to an exhaust manifold 2b. A change-over valve 3 and a ternary catalyser 4 are provided in the rear part of the manifolds. In high load level operation, the operative cylinder selecting controller 15 makes the total cylinders operating changing the change-over valve 3 to a position (b). In low load level operation, the controller 15 makes only the second group (#4-#6) operative changing the changeover valve to a position (a), at the same time, signals of an oxygen sensor 5 provided for an exhasut pipe 6, a suction sensor 12 and a revolving rate sensor 13 are sent to a control circuit 11 and the feedback is temporarily interrupted, thus preventing mulfunction caused by the variation of the component of the exhaust gas that occures during the operation of the change-over valve 3. |
