Rear Muffler Assembly

Abstract

A rear muffler assembly for an internal combustion engine has a first and a second muffler through which exhaust gases flow and which are separated from one another. The first and second mufflers have in each case an exhaust gas delivery and discharge through an exhaust gas routing pipe issuing into an exhaust pipe which follows downstream and in which an exhaust gas shutoff flap which can be closed temporarily is disposed. The rear muffler assembly contains two exhaust gas routing pipes, the first exhaust gas routing pipe having within the rear muffler an issue orifice for exhaust gases positively emerging from the second exhaust gas routing pipe, with the exhaust gas shutoff flap closed, into which first exhaust gas routing pipe the exhaust gases from the internal combustion engine flow directly.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The single FIGURE of the drawing is a diagrammatic, sectional view through a rear muffler assembly with the two exhaust gas routing pipes and with the individual chambers according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the single FIGURE of the drawing in detail, therein is shown a rear muffler assembly 1 containing two mufflers S1 and S2 which are disposed so as to be separated from one another via a closed bottom 2 and which have an identical set-up, so that only one muffler is described.

The exhaust gas routing pipe 3 of the rear muffler are connected in each case to a non-illustrated exhaust gas connection of an internal combustion engine. The exhaust gases are conducted in the direction of the arrows through exhaust gas routing pipes 3 and, depending on the position of an exhaust gas shutoff flap 4 in an exhaust pipe 5, through a further exhaust gas routing pipe 6.

The exhaust gas routing pipes 6 and 3 are generally held within the rear muffler assembly 1 in bottoms (partitions) 7, 8, 9 which subdivide the chambers K1, K2 and K3. The first exhaust gas routing pipe 6 has an inner issue orifice 10 which lies in the chamber K1, extends through the two adjoining chambers K2 and K3 and issues outward.

The second exhaust gas routing pipe 3 extends from an outer issue orifice 20 through the chambers K1, K2 and K3 and likewise issues outward into the exhaust pipe 5 associated with the internal exhaust gas shutoff flap 4.

The second exhaust gas routing pipe 3 has in the second chamber K2 a pipe region R1, which is perforated, that is to say is provided with holes, and which is surrounded by a perforated sheet metal cage 11. The latter is covered all round with material 12 which extends as far as a shell 13 of the rear muffler assembly 1. A clearance is provided between the perforated pipe region R1 and the sheet metal cage 11. A following pipe region R2 of the exhaust gas routing pipe 3 is perforated, that is to say, is configured with holes which are surrounded directly by insulating material 12a. Matching the pipe region R2, a pipe region R3 of the first exhaust gas routing pipe 6 is perforated, that is say provided with holes, in the same chamber K3.

With the exhaust gas shutoff flap 4 open, the exhaust gases from the internal combustion engine can flow, undamped, outward through the exhaust gas routing pipes 3 and 6. By contrast, with the exhaust gas shutoff flap 4 closed, the exhaust gases flow positively only via the perforated pipe sections R1 and R2 of the second exhaust gas routing pipe 3, on the one hand, through the partition 7, provided with holes 15, between the two chambers K1 and K2 to the issue orifice 10 and, on the other hand, through the perforated pipe section R3 of the first exhaust pipe 6. A damped exhaust gas noise simultaneously occurs via the outflow of the exhaust gases through the insulating material 12, 12a.

Claims

1. A rear muffler assembly for an internal combustion engine, the rear muffler assembly comprising: first and second mufflers through which exhaust gases flow and are separated from one another, said first and second mufflers each having an exhaust gas delivery and discharge through an exhaust gas routing pipe assembly issuing into an exhaust pipe which follows downstream and an exhaust gas shutoff flap being temporarily closeable disposed in said exhaust gas routing pipe assembly, said exhaust gas routing pipe assembly having two exhaust gas routing pipes including a first exhaust gas routing pipe and a second exhaust gas routing pipe, said first exhaust gas routing pipe having an issue orifice formed therein for the exhaust gases emerging positively from said second exhaust gas routing pipe with said exhaust gas shutoff flap closed, into said first exhaust gas routing pipe the exhaust gases from the internal combustion engine flow directly.

2. The rear muffler assembly according to claim 1, further comprising first, second, and third chambers; andwherein said second exhaust gas routing pipe has for a positive discharge of the exhaust gases, with said exhaust gas shutoff flap closed, two perforated pipe sections disposed in each case in said second and said third chambers, said two perforated pipe sections including a first perforated pipe section and a second perforated pipe section.

3. The rear muffler assembly according to claim 2, wherein said first chamber contains said issue orifice of said first exhaust gas routing pipe, said first chamber has a partition formed with perforated holes therein, oriented toward said second chamber;further comprising a perforated sheet metal pot surrounding said second chamber; andfurther comprising an insulting material surrounding said perforated sheet metal pot.

4. The rear muffler assembly according to claim 2, wherein: said third chamber follows downstream of said second chamber and has partitions closing said third chamber; andsaid second perforated pipe section of said second exhaust gas routing pipe is disposed in said third chamber and has an insulating material surrounding said second perforated pipe section.

5. The rear muffler assembly according to claim 4, wherein: said first exhaust gas routing pipe has a third perforated pipe section disposed in said third chamber; andsaid second perforated pipe section of said second exhaust gas routing pipe is disposed, to match said third perforated pipe section of said first exhaust gas routing pipe, in said third chamber.

6. The rear muffler assembly according to claim 5, wherein when said exhaust gas shutoff flap is closed, a branched-off exhaust gas stream flows via said first perforated pipe section of said second exhaust gas routing pipe into said issue orifice of said first exhaust gas routing pipe, and a further branched-off exhaust gas stream flows via the second perforated pipe section in said third chamber into said second perforated pipe section of said first exhaust gas routing pipe.