JPS61125619U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the first embodiment of this invention;
Fig. 2 is a characteristic diagram showing its silencing characteristics in comparison with conventional ones, Fig. 3 is a sectional view showing the second embodiment of this invention, and Figs. 4 and 5 are air columns generated in the exhaust system, respectively. An explanatory diagram showing the sound pressure mode of resonance, FIG. 6 is a principle diagram of a side branch type silencing element, and FIG. 7 is a sectional view of a conventional pre-muffler. 4...Volume chamber, 5...Exhaust outlet pipe, 6...Valve housing, 7...Exhaust inlet pipe, 9...Bypass pipe, 10...Flow path switching valve, 24...Volume chamber, 25...
...Exhaust pipe, 26...Exhaust inlet pipe, 27...Inlet insertion pipe, 28...Outlet insertion pipe, 29...Opening/closing valve, 3
3...Return spring.

Claims (1)

[Scope of utility model registration request] A volume chamber that functions as a resonance chamber for low-frequency pulsating noise, an exhaust passage that is branched from the exhaust pipe on the exit side and functions as the neck tube of the resonance chamber or a part of the exhaust flow path at low engine speeds, and A pre-muffler for an automobile engine, comprising an on-off valve that sometimes closes the tip of the exhaust passage to define a side branch part.