JPS57129222A - Supercharger-equipped engine - Google Patents

Abstract

PURPOSE:To improve accelerated responding performance, by providing an auxiliary air-sucking passage, sectional area of which is smaller than that of a main air-sucking passage, in such a manner that its one end is opened to a bypass on the lower stream than a check valve and the other end is opened to the main air-sucking passage in the neighborhood of a suction valve, and also by making a main throttle valve open later than an auxiliary throttle valve. CONSTITUTION:An auxiliary air-sucking passage 70 is formed to have a smaller sectional area than a main air-sucking passage 44, particularly a main air-sucking passage 44B on the downstream side in the neighborhood of a main throttle valve 66, and its one end is opened to a bypass 54 on the lower stream than a check valve 56, and the other end is opened to the main air-sucking passage 44B in the neighborhood of a suction valve 12. An auxiliary throttle valve 72 is arranged in this auxiliary air-sucking passage 70, and the main throttle valve 66 is set to start opening later than the auxiliary throttle valve 72. And therefore, at the time of accelerating speed from medium and low speeds, the check valve 56 is opened to allow air to flow into the bypass 54, and the major part of the air passes through the auxiliary air-sucking passage 70, and at the time of opening of the suction valve 12, the air flows into a combustion chamber to cause a storng swirl to occur.