Arrangement for internal combustion engine
A sound-absorbing exhaust system for an internal combustion engine. The system may comprise a receptacle, an inlet which is arranged in the receptacle and through which exhaust gases can be directed into the same, and a discharge pipe, which connects the interior of the receptacle to the ambient air and through which exhaust gases can be discharged from the same. The discharge pipe may have, at its end positioned outside the receptacle, a seal, which substantially seals the discharge pipe at this end. The discharge pipe may have at least one, but also a plurality of radial holes, which are positioned outside the receptacle. The system may further include a sleeve, which wholly or partially surrounds the discharge pipe outside the receptacle. This arrangement may reduce the emission of exhaust gas noise from the system.
This U.S. nonprovisional application claims priority under 35 U.S.C. § 119 to Swedish Patent Application No. 0401554-1 filed Jun. 17, 2004, the contents of which are incorporated by reference in its entirety.
FIELD OF THE INVENTIONThe present invention relates to a sound-absorbing exhaust system for an internal combustion engine, said exhaust system comprising a receptacle, an inlet which is arranged in the receptacle and through which exhaust gases can be directed into the receptacle, and a discharge pipe, which connects the interior of the receptacle to the ambient air and through which exhaust gases can be discharged from the receptacle.
BACKGROUND ARTSound-absorbing exhaust systems may be used for internal combustion engines of various types, for example smaller ones, which are used, for example, in mopeds, lawnmowers and the like.
The sound-absorbing exhaust system may serve to reduce the noise arising as exhaust gases leave the internal combustion engine, for the purpose of reducing acoustic nuisances.
SUMMARY OF THE INVENTIONExample embodiments of the present invention may provide a sound-absorbing exhaust system which reduces the noise emission from an internal combustion engine.
In an example embodiment, the present invention is directed to a sound-absorbing exhaust system for an internal combustion engine, said exhaust system comprising a receptacle, an inlet which is arranged in the receptacle and through which exhaust gases can be directed into the receptacle, and a discharge pipe, which connects the interior of the receptacle to the ambient air and through which exhaust gases can be discharged from the receptacle, wherein the discharge pipe at its end positioned outside the receptacle has a seal, which substantially seals the discharge pipe at this end, that the discharge pipe has at least one radial hole, which is positioned outside the receptacle, and that a sleeve wholly or partially surrounds the discharge pipe outside the receptacle.
In another example embodiment, the present invention may relate to a sound-absorbing exhaust system where the discharge pipe at its end positioned outside the receptacle has a seal, which substantially seals the discharge pipe at this end, where the discharge pipe has at least one radial hole, which is positioned outside the receptacle, and where a sleeve wholly or partially surrounds the discharge pipe outside the receptacle.
Such an arrangement may reduce the noise emission from an internal combustion engine. Tests have demonstrated that the exhaust gas noise from the engine may decrease by 3 dB. Moreover the frequency content of the remaining noise may be such that it is experienced as less “sharp”, and therefore the noise may be less disturbing.
The discharge pipe may have a plurality of radial holes, which are positioned outside the receptacle. Exhaust gases may be spread in the space between the discharge pipe and the sleeve in a suitable manner.
In an example embodiment, the seal may include a star crimp.
In an example embodiment, the sleeve may be attached to the receptacle, and may project from the receptacle to the same extent as does the discharge pipe, which may result in improved absorption.
In an example embodiment, the receptacle may be elongate in the longitudinal direction of the discharge pipe, and the discharge pipe may extend into the receptacle, at least along half the length of the receptacle.
The receptacle may be, in the longitudinal direction, divided into a plurality of chambers by one or more gas-permeable partitions. This may result in improved sound-absorption.
In an example embodiment, the discharge pipe may have at its end positioned in the receptacle a seal and a plurality of radial holes. Thus the discharge pipe may have the same design at both ends, which may be advantageous in terms of manufacture.
BRIEF DESCRIPTION OF FIGURES
The discharge pipe 4 may have at least one, but also a plurality of, for example about 50, radial holes 6, distributed in three rows for example, which holes may be positioned outside the receptacle 2. The holes may be radial with regard to the longitudinal (axial) direction of the discharge pipe and may, for example, have a diameter of 3.5 mm. In an example embodiment, the discharge pipe 4 has also at the end positioned in the receptacle 2 a seal 15 and a plurality of radial holes 16. Thus both ends of the discharge pipe can have the same appearance. As shown, also the inner part of a discharge pipe 20 can be configured in the same way.
Outside the receptacle 2 the outer sleeve 7 may wholly or partially surrounds the discharge pipe 4 in the radial direction. In an example implementation, the sleeve may be 5 cm long and has an outer diameter of 5 cm. The sleeve 7 may be attached to the receptacle 2, for example welded to the same.
The sleeve 7 may project to about the same extent from the receptacle 2 as does the discharge pipe 4, but may also project longer or shorter. The sleeve 7 may give, together with the seal 5 and the radial holes 6, a pressure, pulse and/or flow equalising effect, which may reduce the noise level. These additional features may be provided at a relatively low cost.
The receptacle 2 may be elongate in the longitudinal direction of the discharge pipe 4. The discharge pipe 4 may extend into the receptacle 2, at least along half the length of the receptacle 2.
As is evident from
On the whole, the noise level may be about 3 dB lower for the system according to an example embodiment of the present invention. In addition, the reduction may be achieved substantially in the range of 400 Hz-5 kHz, which gives a significantly less sharp and disturbing sound.
The invention is not limited to the example embodiments described above and can be varied within the scope of the appended claims.
Claims
1. A sound-absorbing exhaust system for an internal combustion engine, said exhaust system comprising:
- a receptacle,
- an inlet which is arranged in the receptacle and through which exhaust gases can be directed into the receptacle, and
- a discharge pipe, which connects the interior of the receptacle to the ambient air and through which exhaust gases can be discharged from the receptacle,
- wherein the discharge pipe at its end positioned outside the receptacle has a seal, which substantially seals the discharge pipe at this end, that the discharge pipe has at least one radial hole, which is positioned outside the receptacle, and that a sleeve wholly or partially surrounds the discharge pipe outside the receptacle.
2. A sound-absorbing exhaust system as claimed in claim 1, in which the discharge pipe has a plurality of radial holes, which are positioned outside the receptacle.
3. A sound-absorbing exhaust system as claimed in claim 1, in which the seal includes a star crimp.
4. A sound-absorbing exhaust system as claimed in claim 1, in which the sleeve is attached to the receptacle.
5. A sound-absorbing exhaust system as claimed in claim 4, in which the sleeve projects from the receptacle to the same extent as does the discharge pipe.
6. A sound-absorbing exhaust system as claimed in claim 1, in which the receptacle is elongate in the longitudinal direction of the discharge pipe, and the discharge pipe extends into the receptacle, at least along half the length of the receptacle.
7. A sound-absorbing exhaust system as claimed in claim 6, in which the receptacle in the longitudinal direction is divided into a plurality of chambers by means of at least one gas-permeable partition.
8. A sound-absorbing exhaust system as claimed in claim 1, in which the discharge pipe at its end positioned in the receptacle has a seal and a plurality of radial holes.
Type: Application
Filed: Jun 15, 2005
Publication Date: Dec 22, 2005
Inventor: Lars Birgersson (Tranas)
Application Number: 11/152,198