Patent Application
20220307399
This disclosure relates to exhaust silencers for vehicle exhaust system and more particularly to shielding one or more components of the exhaust silencer from exhaust jets.
Motor vehicles may include an engine that combusts fuel to produce power. Byproducts of combustion include noise and exhaust gases. An exhaust system is provided to reduce noise and carry the exhaust gases away from the vehicle. The exhaust system may include one or more exhaust silencers, such as resonators or mufflers, to reduce a noise level of the vehicle.
According to one embodiment, a vehicle exhaust system includes an exhaust silencer. The silencer includes a housing defining an interior and a tube disposed in the interior and having an opening. A gas-flow deflector is disposed in the interior in alignment with the opening such that a jet of exhaust gases exiting the opening contacts the deflector to provide heat shielding to a wall of the housing. The deflector has a deflector plate with a front side facing the opening and a backside completely spaced from the wall of the housing.
According to another embodiment, an exhaust silencer includes a housing defining an interior and a tube disposed in the interior and defining an opening. A gas-flow deflector is configured to heat shield an interior wall of the housing from exhaust gases exiting the opening. The deflector has a deflector plate and a riser. The riser has a first portion connected to the interior wall and a second portion connected to a backside of the deflector plate to suspend the deflector plate in the interior such that the backside is completely spaced from the interior wall to form an insulating airgap therebetween.
According to yet another embodiment, an exhaust silencer includes a housing and a transverse wall disposed in the housing and defining a pair of chambers. A tube having an opening is configured to expel an exhaust jet towards the transverse wall. A deflector is attached to the transverse wall and is disposed within a path of the jet to redirect the jet away from the transverse wall.
Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
Referring to
The housing 28 defines an interior 30 bounded by inner walls of the shell 22 and headers 24, 26. One or more partitions, such as partitions 32 and 34, are disposed within the interior 30 to form acoustic chambers, such as chambers 36, 38, and 40. The partitions (which may also be known as baffles) may be transverse walls that are oriented orthogonal to the longitudinal direction of the housing 28. The transverse walls may be formed of metal and are joined to the shell 22 such as by welding or the like.
The headers 24, 26 and the partitions 32, 34 have aligned openings 42 for receiving tubes therethrough. Each of the openings may include a collar or flange surrounding a periphery of the opening. In the illustrated embodiment, the silencer 20 uses a retroverted gas flow path to provide sound attenuation. Exhaust gases enter the housing 28 through an inlet tube 44 that extends through the front header 26 and the partitions 32 and 34. The inlet tube 44 defines an opening 46 that expels a jet of exhaust gases into the rear chamber 36. An internal tube 48 defines an inlet opening 50 disposed in the rear chamber 36 and an outlet opening 52 disposed in the front chamber 40. The internal tube 48 connects the chambers 36 and 40 in acoustic and fluid communication. An outlet tube 54 extends from an inlet opening 56 through the partitions 32, 34 and out of the housing 28 through the rear header 24. Portions of one or more of the tubes 44, 48, and 54 may be perforated in select locations. During operation of the engine, exhaust gases enter into the silencer 20 through the inlet tube 44 creating a high-pressure zone in the rear chamber 36. The exhaust gases then travel through the internal tube 48 to the front chamber 40. The outlet tube 54 carries the exhaust gases from the front chamber 40, through the middle chamber 38 and the rear chamber 36, and out of the silencer 20 to a downstream exhaust pipe. While not shown, sound deadening materials, such as glass fiber pack, may be disposed within one or more areas of the interior 30.
Exhaust gases, which are hot and under pressure, jet from the openings of the tubes and contact interior surfaces of the housing. The interior surfaces opposite the openings receive the brunt of the high-velocity and high-heat exhaust jet. These interior surfaces become hot spots and are more prone to premature wear than other areas of the silencer 20 due to thermal fatigue, corrosion, and the like.
The housing material subjected to high thermal cycles may experience dry corrosion mechanisms. In a high-temperature oxidizing environment, chemical reactions may form a protective oxide layer for a period of time, which eventually gives way to spalling and scaling. The high-temperature oxidizing environment may also form a non-protective oxide that promotes oxygen penetration into the metal leading to internal oxidation, which may render the material brittle. Additionally, most oxides have different coefficients of thermal expansion than the metal housing creating thermal stresses when the temperature changes. The differential thermal expansion may cause fragments of the oxides to break away from the housing promoting metal loss. These loose fragments may also rattle and/or cause blockages within the silencer.
Referring to
The deflector 60 may include a deflector plate 66 having a front side 68 and a backside 70. The front side 68 faces the exhaust jet 62 and is configured to redirect the jet 62 away from the interior wall 64. To lesson thermal conduction, the deflector plate 66 is spaced from the interior wall 64 to form an insulating air gap 72 between the backside 70 and the wall 64. The deflector plate 66 may be attached to the header 26 by a riser 74. The riser 74 and the deflector plate 66 may be separate components that are joined together by welding, fasteners, mechanical joining, or the like. The riser 74 may have an elongate body 76 having a generally rectangular shape. In the illustrated embodiment, the riser 74 includes a first edge 80 attached to the backside 70 of the deflector plate 66, a second edge 82 attached to the wall 64, a top 84, a bottom 86, and opposing faces 88 that extend vertically from the top 84 to the bottom 86 and extend laterally from the first edge 80 to the second edge 82. The riser 74 may include a height defined between the top and the bottom, a width defined between the first and second edges, and a thickness defined between the faces. In the illustrated example, the riser 74 is substantially wider than it is thick and is substantially taller than it is wide forming a thin, slender rectangular prism. This, of course, is only one example, and the riser may have any suitable shape for suspending the deflector plate 66 in the flow path of an exhaust jet and spaced apart from a wall of the housing.
The deflector plate 66 may be curved to have a generally concaved shape on the front side 68 as shown in
Referring to
Referring back to
The size, shape, and location of the deflectors 60 and 100 merely illustrate an example configuration of an exhaust silencer. These parameters are dependent upon the specific design of the exhaust flow path through the silencer and other locations, shapes, orientation, and sizes of the deflectors is contemplated. Additionally, while two deflectors are shown in the illustrated embodiment of
Reducing the heat exposure of the housing 28 may also provide overall vehicle benefits in addition to the silencer itself. Silencers are packaged under the vehicle in close proximity to many other vehicle components such as brake lines, electronics, powertrain components, and the like. Extensive heat shielding is frequently provided to protect these components from the silencer. By employing the above-described deflectors, the surface temperature of the silencer may be reduced resulting in decreased need for heat shielding. This may provide an opportunity for cost reduction in the overall vehicle package. High-temperature hotspots may cause welding failure, leading to vibrations and noise. The proposed disclosure aims to reduce this failure. The proposed deflectors may also homogenize temperature of the silencer.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and can be desirable for particular applications.
