GB755399A - Improvements in silencers for gaseous currents - Google Patents

Abstract

755,399. Silencers for gaseous currents. GENERAL MOTORS CORPORATION. Nov. 1, 1954 [Nov. 16, 1953], No. 31482/54. Class 7(2) A silencer 13, Fig. 1, e.g. for the induction system of an I.C. engine, comprises a single resonator chamber 51 which communicates with a sound-transmission passage 24 by way of a number of acoustical coupling passages of different inertance values. As shown in Fig. 1, the silencer 13 comprises the soundtransmitting passage 24 for connection to the induction system, an air collecting chamber 28, an air filter unit and air passage 17, 32, an oil supply chamber 36 and an annular air inlet passage 39. The resonating chamber 51 has a predetermined acoustical capacitance value suitable for attenuating sounds of different frequency emanating from the engine and is acoustically coupled with the passage 24 by an annular passage 52 formed between conduits 43, 44, the conduit 43 being provided with openings 53. 54 of different cross-sectional area. In modifications, (a) the resonating cham ber 57, Fig. 2, is acoustically coupled to the sound-transmitting passage 26 by openings 58 in the conduit 46 which is connected to the induction system, openings 61, smaller in cross-sectional area than the openings 58, in the conduit 47, and part of the annular passage 59 between the openings 58, 61; also, the chamber is coupled to the passage 26 through the openings 58 and the length of the passage 59 between these openings and the end of the conduit 47, and (b) the resonating chamber 63, Fig. 3, communicates with the sound-transmitting passage 27 by the openings 64, the width of the annular passage between the conduits 48, 49, and the openings 67, of less cross-sectional area than the openings 64, in the conduit 49; also, the chamber communicates with the passage 27 by the acoustical coupling provided by the openings 64 and the outer end of the passage 66. A second resonating chamber 69 is acoustically coupled to the passage 27 by openings 71 and the lower extremity of the passage 66.