| 摘要 |
PURPOSE:To enhance the performance of a three-valve type internal combustion engine over the entire operating range of the engine, by providing throttle valves in intake-air pipes communicated with two intake-air valves, and as well by opening and closing the throttle valves in accordance with both rotational speed and load of the engine. CONSTITUTION:In an internal combustion engine in which each cylinder is provided thereto with an exhaust valve 1 and low and high load intake-air valves 2a, 2b, an ignition plug 6 is disposed at a position opposing the intake-air valve 2b, and intake-air pipes 4a, 4b which are communicated with the intake-air valves 2a, 2b are branched off from a main intake-air pipe downstream of a main throttle valve 14. Further, throttle valves 3a, 3b are disposed in the intake- air pipes 4a, 4b, respectively, and gears 12a, 12b on the shafts 5a, 5b of the throttle valves 3a, 3b are meshed with each other with the throttle valve shaft 5a being urged in the opening direction of the throttle valve. Further, actuators 8a, 8b are controlled such that the throttle valve 3a is alone opened in a low load operating range, but the throttle valve 3b is alone opened in a low speed and high load operating range while both valves 3a, 3b are opened in middle and high speed and high load ranges. |
