Active design of exhaust sounds

Patent metadata

Field	Value
Publication number	US-9728176-B2
Application number	US-201514636667-A
Country	US
Kind code	B2
Filing date	Mar 3, 2015
Priority date	Mar 4, 2014
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A sound generator ( 1 ) includes a casing ( 10 ) with at least one exhaust gas inlet ( 11 ) and at least one exhaust gas outlet ( 12 ) that is different from the at least one exhaust gas inlet ( 11 ) and at least one electro-acoustical transducer ( 20 ). The electro-acoustical transducer ( 20 ) is configured to produce sound in dependence on an electrical control signal. The electro-acoustical transducer ( 20 ) is located within the casing or directly attached to the casing. An active noise control system ( 9 ) includes the sound generator ( 1 ). A vehicle ( 8 ) with an internal combustion engine ( 6 ) includes the active noise control system ( 9 ).

First claim

What is claimed is:

1. A sound generator for an active noise control system for a vehicle with an internal combustion engine, the sound generator comprising:
a casing with at least one exhaust gas inlet and at least one exhaust gas outlet different from the at least one exhaust gas inlet;
an electro-acoustical transducer configured to produce sound in dependence on an electrical control signal, the electro-acoustical transducer being located directly attached to the casing and the electro-acoustical transducer comprising a moving coil loudspeaker directly attached to the casing, wherein the casing comprises a hole or plural holes at a direct attachment position of the electro-acoustical transducer, the electro-acoustical transducer covering the hole or holes in the casing, wherein sound generated by the electro-acoustical transducer is superimposing sound supplied to the casing together with exhaust gas via the at least one exhaust gas inlet within the casing; and
at least one flexible membrane coupled to the casing in an air-tight manner so as to separate the electro-acoustical transducer from the at least one exhaust gas inlet and the at least one exhaust gas outlet, wherein the at least one flexible membrane is provided in addition to the electro-acoustical transducer and the at least one flexible membrane is suitable to prevent corrosive exhaust gas from reaching the electro-acoustical transducer while sound waves generated by the electro-acoustical transducer enter the casing via the flexible membrane.

2. A sound generator according to claim 1 , wherein the casing comprises at least one of:
a chamber in fluid communication with both the at least one exhaust gas inlet and the at least one gas outlet wherein the chamber is at least one of lined with sound absorbing material and provided with roving fiberglass; and
a resonating chamber, harmonically tuned to cause destructive interference comprising a cavity resonator using Helmholtz resonance.

3. A sound generator according to claim 1 , wherein the electro-acoustical transducer comprises an acoustic diaphragm, the acoustic diaphragm being located at a spaced location from the at least one flexible membrane.

4. A sound generator according to claim 3 , wherein the acoustic diaphragm forms part of a walling of the casing and is comprised of a material different from a material of a remainder of the walling of the casing.

5. A sound generator according to claim 1 , further comprising:
a bridge wall within the casing and coupled to the casing so as to define at least two chambers separated from one another by the bridge wall;
a supply conduit connected to one of the at least one exhaust gas inlet, extending through one of the chambers and communicating with another of the chambers; and
an exhaust conduit within the casing and connected to the at least one exhaust gas outlet, extending through one of the chambers and communicating with another of the chambers.

6. A sound generator according to claim 5 , wherein the supply conduit comprises a supply conduit section and the exhaust conduit comprises an exhaust conduit section wherein the supply conduit section is supported extending in parallel to the exhaust conduit section.

7. A sound generator according to claim 5 , wherein at least one of:
the bridge wall is perforated; and
one or more of the supply conduit and the exhaust conduit is perforated.

8. A sound generator according to claim 1 , further comprising:
a bridge wall within the casing and coupled to the casing so as to define first and second chambers separated from one another by the bridge wall;
a supply conduit connected to one of the at least one exhaust gas inlet and extending through the first chamber and communicating with the second chamber; and
an exhaust conduit connected to the at least one exhaust gas outlet and extending through the first chamber and communicating with the second chamber, wherein the electro-acoustical transducer is arranged opposing an open end of at least one of the supply and exhaust conduits.

9. A sound generator according to claim 8 , wherein the supply conduit comprises a supply conduit section and the exhaust conduit comprises an exhaust conduit section wherein the supply conduit section is supported extending in parallel to the exhaust conduit section.

10. A sound generator according to claim 8 , wherein at least one of:
the bridge wall is perforated; and
one or more of the supply conduit and the exhaust conduit is perforated.

11. A sound generator according to claim 1 , further comprising:
a first bridge wall within the casing and coupled to the casing;
a second bridge wall within the casing and coupled to the casing, the first bridge wall, the second bridge wall and the casing cooperating to define first, second and third chambers separated from one another by the bridge walls;
a supply conduit connected to the at least one exhaust gas inlet and extending through the first and second chambers and communicating with the third chamber; and
an exhaust conduit connected to the at least one exhaust gas outlet and extending through the third and second chamber and communicating with the first chamber, wherein the electro-acoustical transducer is arranged opposing an open end of the supply and exhaust conduits.

12. A sound generator according to claim 11 , wherein the supply conduit comprises a supply conduit section and the exhaust conduit comprises an exhaust conduit section wherein the supply conduit section is supported extending in parallel to the exhaust conduit section.

13. The sound generator according to claim 1 , further comprising:
an additional exhaust gas inlet;
an additional exhaust gas outlet;
a bridge wall within the casing and coupled to the casing so as to define at least two chambers separated from one another by the bridge wall;
a supply conduit connected to the at least one exhaust gas inlet, extending through one of the chambers and communicating with another of the chambers;
an additional supply conduit connected to the additional exhaust gas inlet, extending through one of the chambers and communicating with another of the chambers;
an exhaust conduit connected to the at least one exhaust gas outlet;
an additional exhaust conduit connected to the additional exhaust gas outlet;
an additional electro-acoustical transducers, wherein:
the electro-acoustical transducer is arranged opposing an open end of the supply conduit connected to the at least one exhaust gas inlet and the additional electro-acoustical transducer is arranged opposing an open end of the additional supply conduit; or
the electro-acoustical transducer is arranged opposing an open end of the exhaust conduit connected to the at least one exhaust gas outlet and the additional electro-acoustical transducer is arranged opposing an open end of an exhaust conduit connected to the additional exhaust gas outlet.

14. A sound generator according to claim 1 , further comprising a second casing different from the casing, the second casing being attached to the casing, wherein the second casing houses the electro-acoustical transducer.

15. A sound generator according to claim 1 , wherein the one or more holes has a hole diameter, the moving coil comprising a diaphragm, the diaphragm having a diaphragm diameter, the diaphragm diameter being greater than the hole diameter, the casing comprising a wall having a first portion and a second portion, the first portion being located opposite the second portion, the wall defining at least one of the one or more holes, wherein the at least one of the one or more holes is located be

Assignees

• Eberspächer Exhaust Tech Gmbh & Co Kg

Inventors

• Keck Mathias
• Romzek Martin

Classifications

• F01N2490/08

  Two or more expansion chambers in series separated by apertured walls only · CPC title

• F01N2470/02

  Tubes being perforated · CPC title

• G10K11/175 Primary

  using interference effects; Masking sound · CPC title

• H04R2499/13

  Acoustic transducers and sound field adaptation in vehicles · CPC title

• G10K2210/32272

  Helmholtz resonators · CPC title