# US 9,752,475 B2 · Exhaust system for an internal combustion engine

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- Number: US 9,752,475 B2
- Document ID: US9752475B2
- Status: Granted
- Kind: B2
- Application number: 15/248,870
- Filed: 2016-08-26
- Published: 2017-03-02
- Granted: 2017-09-05
- Earliest claimed: 2015-08-27
- Assignees: Audi AG
- Applicants: Audi AG
- Inventors: Axel Peters; Siamak Alizadeh; Gerd Verbeck
- Web page: https://patentgrep.com/patent/US9752475B2

## CPC

- G10K 11/178: by electro-acoustically regenerating the original acoustic waves in anti-phase
- F01N 1/165: {for adjusting flow area}
- F01N 1/166: {for changing the flow path through the silencer or for adjusting the dimensions of a chamber or a pipe (F01N1/165 takes precedence)}
- F01N 1/168: {for controlling or modifying silencing characteristics only}
- F01N 13/011: {having two or more purifying devices arranged in parallel}
- F01N 13/02: having two or more separate silencers in series
- F01N 13/04: having two or more silencers in parallel, e.g. having interconnections for multi-cylinder engines
- F02M 26/14: in relation to the exhaust system
- G10K 11/161: {in systems with fluid flow (G10K11/162 takes precedence; gas flow silencers or exhaust apparatus for machines or engines in general or for internal combustion engine F01N, noise absorbers in pipes or pipe systems F16L55/02; noise absorption in air conditioning and ventilation F24F13/24; silencing exhaust or propulsion jets in aircraft B64D33/06)}
- F01N 1/065: {by using an active noise source, e.g. speakers}
- G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF

## Abstract

An exhaust system for an internal combustion engine includes a muffler, a first exhaust pipe which is connected to the muffler for sound damping, and a second exhaust pipe which extends in terms of flow in parallel relation to the first exhaust pipe and extends through first muffler in the absence of a flow communication with the first muffler. The first and second exhaust pipes originate from a common exhaust pipe. A switching valve adjusts hereby a throughflow cross section of the second exhaust pipe.

## Claims

### Claim 1

An exhaust system for an internal combustion engine, comprising:
a first muffler;
a first exhaust pipe connected to the first muffler for sound damping;
a second exhaust pipe extending in terms of flow in parallel relation to the first exhaust pipe and configured to extend through the first muffler in the absence of a flow communication with the first muffler, said first and second exhaust pipes originating from a common exhaust pipe;
a switching valve configured to adjust a throughflow cross section of the second exhaust pipe; and
at least one second muffler disposed upstream of the first muffler, said first exhaust pipe connected to the second muffler for sound damping, said second exhaust pipe extending through the second muffler in the absence of a flow communication with the second muffler.

### Claim 2 (depends on 1)

The exhaust system of claim 1, wherein the switching valve is configured as an exhaust gas recirculation valve, further comprising an exhaust gas recirculation pipe disposed upstream of the switching valve branching off the second exhaust pipe or the common exhaust pipe.

### Claim 3 (depends on 1)

The exhaust system of claim 1, wherein the switching valve is disposed downstream of the muffler.

### Claim 4 (depends on 1)

The exhaust system of claim 1, wherein the first muffler is constructed as rear muffler.

### Claim 5 (depends on 1)

The exhaust system of claim 1, wherein the first exhaust pipe causes a pressure loss which is greater than a pressure loss caused by the second exhaust pipe, when the switching valve is open.

### Claim 6 (depends on 1)

The exhaust system of claim 1, wherein the switching valve is constructed as discretely switching valve or as proportional valve.

### Claim 7 (depends on 1)

The exhaust system of claim 1, further comprising an exhaust gas aftertreatment device disposed in at least one of the first and second exhaust pipes.

### Claim 8 (depends on 1)

The exhaust system of claim 1, further comprising a sound tube disposed downstream of the switching valve and feeding into the second exhaust pipe.

### Claim 9 (depends on 1)

The exhaust system of claim 1, wherein the first and second exhaust pipes feed into separate end pipes downstream of the first muffler.

### Claim 10 (depends on 1)

The exhaust system of claim 1, wherein the first exhaust pipe is of discontinuous configuration inside the first muffler to define a first sub-section and a second sub-section to enable exhaust to enter an inner volume of the first muffler from the first sub-section and to enable exhaust to enter the second sub-section from the inner volume of the first muffler.

### Claim 11 (depends on 1)

The exhaust system of claim 1, wherein the first and second sub-sections of the first exhaust pipe overlap one another so as to extend side-by-side.