| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact muffling device capable of coping with a wave length variation in a sound wave by a load variation, and suitable for a reciprocating type internal combustion engine for generating a low frequency.SOLUTION: Both ends of one connecting pipe 3 are connected to and made to communicate with an exhaust pipe 1, a partition wall 4 is arranged in its midway, and a first muffling pipe 5 of a length L1 and a second muffling pipe 6 of a length L2 are constituted, and an interval L3 between branch points 7 and 8 is set in an average of the L1 and the L2. The L1 is 1/4 of a wave length λ1 in exhaust gas temperature in a low load, and the L2 is 1/4 of a wave length λ2 in exhaust gas temperature in a high load. A muffling effect is maintained in a range where the exhaust gas temperature exists between a low load time and a high load time. Even if a position of one muffling pipe abuts on a minimum position of sound pressure, since the other abuts on a maximum position, the muffling effect of 20-30 dB can be obtained. |
