| 摘要 |
PURPOSE:To avoid fluctuation of the air-fuel ratio of the mixture fed to a ternary catalyst, during the light-load operation of an engine, by employing such a construction that the intake passage leading to the cylinder to be cut out is divided itno two branches, one of which being provided with a cut-off valve to interrupt the air supply to the cut-out cylinder. CONSTITUTION:Intake and exhausting systems of a multi-cylinder engine is divided into 2 sections and, at the same time, an intake passage 2 is further divided into an operating side air intake passage 4 and a suspension side air intake passage 5. A down-stream passage, in which the passages 4 and 5 join together, is provided with a throttle valve 3 to be operated by an accelerator pedal not shown, and further, the suspension valve side air passage 5 is provided with a cut-off valve 6 and a check valve 20. When an engine is operated with light load, fuel supply to a cylinder on the suspension side is stopped and, at the same time, the cut-off valve 6 is closed, so that air supply to the exhausting system through the air passage 5 is interrupted. |
