| 摘要 |
PURPOSE:To heighten an exhaust flow velocity to an exhaust sensor at low load as well as to aim at improvement in detection responsiveness, by installing the exhaust sensor in a primary side exhaust passage being installed at position separating from the vicinity of an engine body, and also installing a choking member to be closed at low load, in a secondary side exhaust passage. CONSTITUTION:A primary side exhaust passage 8 is connected to a primary side exhaust port 7 or each cylinder of an engine while a secondary side exhaust passage 10 to a secondary suction port, respectively, in a separating manner, and both passages are joined together with each other at the upstream side of a catalyzer 14. An exhaust sensor 15 is installed at a convergent part of the primary side exhaust passage 8 while a shutter valve 18 is installed in the downstream side of an exhaust port 9 of the secondary side exhaust passage 10, respectively. The shutter valve 18 is controlled by an actuator control circuit 24 in which a detection value of a suction pressure sensor 23 is inputted, whereby the secondary side exhaust passage 10 is choked by an actuator 21 in time of low load. |
