| 摘要 |
PURPOSE:To raise rapidly catalyst temperature when engine load exceeds a set value, by making temporarily mixture rich while supplying secondary air only until the mixture reaches a predetermined unburnt component amount set according to engine load. CONSTITUTION:Fuel supply units 6, 16 governs fuel amount supplied to an intake system of an engine 1. A secondary air supply unit 12 supplies secondary air to an exhaust path 7 at the upstream side of an exhaust gas cleaning cata lyst 9. When the engine 1 has load more than a set value upon receiving the output of a load detecting means 17, the mixture is made rich for a predeter mined time while supplying secondary air to the exhaust path 7 so that the temperature of the cleaning catalyst is rapidly raised to the necessary and sufficient one by a kind of forecasting control. Also, this predetermined time can be corrected to be shortened as load becomes high. |
