1. Field of the Invention
The present invention relates to a muffler for an internal combustion engine for use in a motor vehicle, for example, and a method of manufacturing tubes for use in such a muffler.
2. Description of the Prior Art
In general, mufflers, or silencers, of the type to which the invention is directed include a plurality of expansion or resonance chambers into which a muffler body is divided by partitions and which are arranged in its longitudinal direction. The intervas of the chambers are interconnected by associated connecting tubes to conduct combustion gasses, supplied through an inlet tube from a internal combustion engine connected, to the series of the chambers in a predetermined order. The gases blow out of the final chamber into the air via an outlet pipe.
Conventionally, inlet, interconnecting and outlet tubes for use in mufflers of the type described above were made in separate units so as to be combined by end plates and partitions which the tubes are inserted through and supported by. The tubes are generally welded to the end plates and partitions.
In general, improvement of the performance in attenuating noise due to exhaustion of combustion gases gives rise to increasing the volume of mufflers and complicating the internal structural configuration thereof. Specifically, the conventional technique for obtaining performance improvement of mufflers inherently required an increase in kind and number of constituent elements, such as partitions and connecting tubes, involved in a muffler, as well as an increase in welding portions for affixing those elements with each other.
In the prior art, higher performance mufflers are, therefore, heavier in weight and more massive, and require much more time and cost in manufacturing.