| 摘要 |
PURPOSE:To enhance the combustibility and intake-air charge efficiency of an engine, in a device in which a plurality of intake-air valves are provided to each of cylinders, by providing such an arragement that shut-off valves are provided in a part of intake ports, and as well the valve opening times of the plurality of intake-valves are made substantially identical with each other but the valve closing times thereof are made different from each other. CONSTITUTION:In an intake-air device in which two intake-air valves 20A, 20B and two exhaust valves 21A, 21B are provided in each of combustion chambers 19 in an internal combustion engine provided with a supercharger, and two intake ports 3A, 3B and two exhaust ports 5A, 5B that are independently communicated with the above-mentioned intake and exhaust valves are provided in intake-air and exhaust passages 3, 5, a butterfly type shut-off valve 22 is disposed in one intake port 3A. The shut-off valve 22 is closed in the low rotational speed range, but is opened in the high rotational speed range. Further, the intake valves 20A, 20B are controlled to be opened and closed such that the valve opening times of the intake valves 20A, 20B are made substantially identical with each other, and as well the valve closing time of the intake valve 20A is set in the vicinity of the intermediate part of the compression stroke, at, for example, an angle of 30-50 deg. after the bottom dead center while the valve closing time of the intake-air valve 20B is set in the vicinity of the bottom dead center. |
