| 摘要 |
PURPOSE:To enable to obtain an optimum driving performance of an engine while lowering the specific fuel consumption and purifying the exhaust gas, by setting the control region at a load region as high as possible in a low-speed region of engine operation and setting the control region at a low load region in a high speed region of engine operation. CONSTITUTION:At the time of low-speed, low-load operation of an engine, the air-fuel ratio of mixture supplied from a carburetor 1 is controlled by a slow fuel jet 2 and a slow air jet 3. At the time of medium- and high-speed, medium- and high-load operation of the engine, the air-fuel ratio is controlled by a main fuel jet 4 and a main air jet 5. The air-fuel ratio of a slow-speed system and a main system is corrected by a control slow air jet 8 and a control fuel jet 7. Further, the system of this invention comprises an engine-speed detector 14 and either of a throttle valve opening detector 18 or a pressure detector 19. With such an arrangement, required output and mixture ratio are obtained at any region by setting non-control region according to the output signal of the engine- speed detector 14 on the basis of the signals from the above detectors and the metering portions of the two control jets 7, 8 made uncontrolled (closed or fixed) at the time of high-load operation of the engine. |
