SE420004B - Silencer for exhaust gases from combustion engines - Google Patents

Abstract

A silencer for exhaust gases from combustion engines comprises a perforated tube 1 provided with an inlet 2 and an outlet 3, intermediate walls 12, 13, 14 being provided in the interior of said tube and having through flow openings 15, 16. The tube 1 is surrounded by a casing, which by means of separating walls 10, 11 is divided into damping chambers 7, 8, 9. The exhaust gases flow partly axially through the tube 1 and partly from the tube to the damping chambers and from these back to the interior of the tube, where they are mixed with the exhaust gases in the axial flow. <IMAGE>

Description

Figure 1 is an axial section through a muffler 1 according to the invention and Figure 2 is a view taken along the line II-II in Figure 1.

The drawing shows a perforated tube 1 of sheet steel or other suitable material. The pipe 1 has an inlet 2 for exhaust gases from an internal combustion engine and an outlet 3. A tight jacket 4 is arranged around the perforated pipe 1, which has ends 5,6 for sealing connection to the outer surface of the pipe 1. Between the perforated part of the tube 1 and the jacket N, a damping space is formed, which is divided into a plurality of damping chambers 7,8,9 by means of partition walls 10,11. The damping chambers 7,8,9 communicate with each other through the perforated tube 1.

The interior of the perforated tube 1 is divided by means of partitions 12, 13, 1H. The partition walls 10,11 are each located approximately midway between the partition pair 12,13 and 13,11U, respectively. Each partition wall is provided with flow openings, for example the flow openings 15 and 16 in figure 2.

Exhaust gases with pulsating pressure, which are fed into the muffler via the inlet 2, will partly flow out through the perforated pipe 1 in a known manner to a surrounding damping chamber as indicated in Figure 1 through the curved arrows and from the damping chamber flow back into the pipe 1. The outflow from the pipe 1 takes place in front of a partition, since the pressure is greater in front of the wall than behind it and the inflow thus takes place behind a partition. By providing variable partition wall 12, 13, 1H with flow openings, for example 15 and 16, an axially directed exhaust flow is produced through the interior of the perforated tube 1 and this axial exhaust flow, which is pulsating, is mixed with those from the damping chambers 7,8,9 in the tube. 1 inflowing exhaust gases, whereby an effective equalization of the pressure differences in the interior of the perforated pipe is achieved as well as a reduction of the flow resistance. As can be seen from Figure 1, the attenuation chambers are made successively further from the inlet, calculated in order to obtain a successful gas expansion and thus the most efficient possible sound attenuation.

Claims (2)

7.808087-6 PATENT REQUIREMENTS 1. Mufflers for exhaust gases from internal combustion engines, comprising one provided with an inlet (2) and an outlet (3), along its mantle surface perforated pipe (1), the interior of which is arranged to the inner surface of the pipe connecting partitions (l2, l3, l4) and which pipe (l) is surrounded by a dense jacket (H, 5,6), which between it and the pipe forms a space, which by means of partition walls (l0, ll), abutting against the jacket and the pipe, are divided into damping chambers (7,8,9) and which partition walls are located between the partitions, allowing the exhaust gases to flow out of the pipe in front of a partition and out into adjacent chambers and from this chamber back into the pipe behind said partition, characterized in that each partition wall (12, 13, 1H) is provided with a plurality of flow openings (eg 15, 16) for providing a gas flow in the axial direction of the perforated tube. 2. A muffler according to claim 1, characterized in that the distance between the partition walls (l2, l3, 1H) gradually increases in the axial flow direction.