Acoustic barrier, vehicle acoustic barrier system, and a method of assembling a vehicle acoustic barrier system

Abstract

A vehicle acoustic barrier system (100) for a vehicle chassis, the vehicle acoustic barrier system (100) includes: a vehicle chassis compartment (140) enclosing a volume (142), the vehicle chassis compartment (140) having a first interior wall portion (144) circumscribing a portion (143) of the volume (142); and a self-supporting body (101) configured to locate in a located position within the vehicle chassis compartment (140) such that the self-supporting body (101) spans the portion (143). The self-supporting body (101) comprises a perimeter portion (122) extending around the self-supporting body (101). The perimeter portion (122) is configured, in the located position, to provide an interference fit around the first interior wall portion (144). An acoustic barrier (110) for use in the vehicle acoustic barrier system (100), as well as a method of assembling the vehicle acoustic barrier system (100) is also disclosed.

Description

[0001] ACOUSTIC BARRIER, VEHICLE ACOUSTIC BARRIER SYSTEM, AND A METHOD OF ASSEMBLING A VEHICLE ACOUSTIC BARRIER SYSTEM

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to an acoustic barrier, a vehicle acoustic barrier system, and a method of assembling a vehicle acoustic barrier system. Aspects of the invention relate to an acoustic barrier and to a vehicle acoustic barrier system, each having a self-supporting body.

[0004] BACKGROUND

[0005] Vehicles and occupants of vehicle cabins experience noise during use of the vehicle. Noise sources from the vehicle itself include noise from the drive system, such as the internal combustion engine or electric drive unit, or noise from the vehicle tyres moving along the ground. A pathway for noise, typically airborne noise, into the vehicle cabin is through the floor of the vehicle cabin. A vehicle cabin floor is typically provided by an internal vehicle cabin panel that is located internal of a chassis outer wall panel. A compartment located between the vehicle cabin panel and the chassis outer wall panel is typically used to house conduits of vehicle systems, such as for engine exhaust, coolant fluid, brake fluid, or electrical cabling. This compartment then provides a noise pathway for airborne noise into the vehicle cabin, particularly into the front region of the vehicle cabin. A known mitigation of noise in the vehicle cabin is to line the vehicle cabin floor with layers of carpet or similar substrates, typically with integrated mass layers, in order to inhibit transmission of noise. Adopting this approach adds significant mass to the vehicle chassis, for example 10, 20, 30 kilograms, or more. Fitting sheets of carpet or substrate to achieve uniform coverage of the vehicle cabin floor is difficult to achieve, and risks leaving gaps for noise pathways into the vehicle cabin. This is particular so when sheets are required to conform to a vehicle cabin floor with an undulating shape. Accurate fitting of the carpet or substrate is timeconsuming, increasing manufacturing costs.

[0006] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. It would be useful to mitigate noise, particularly airborne noise, in a vehicle cabin. It would also be useful to mitigate noise without adding significant mass to the vehicle. Furthermore, it would be useful to simplify vehicle manufacturing so as to install noise mitigation means, particularly for mitigation of noise from the vehicle cabin floor, quickly and conveniently. It would also be useful to provide a method of installing means for noise mitigation that is compatible with known methods of assembling a vehicle chassis.

[0007] SUMMARY OF THE INVENTION

[0008] Aspects and embodiments of the invention provide a vehicle acoustic barriersystem including a self-supporting body that spans an entrance to a vehicle chassis compartment, as claimed in the appended claims.

[0009] Aspects and embodiments of the invention provide an acoustic barrier including a self-supporting body with a perimeter portion configured to conformingly seal around an interior wall portion of a vehicle chassis compartment.

[0010] Aspects and embodiments of the invention provide a method of assembling a vehicle acoustic barrier system including an acoustic barrier for a vehicle chassis compartment defined by a first vehicle chassis panel and a second vehicle chassis panel, wherein urging the second vehicle chassis panel towards the first vehiclechassis panel to form the vehicle chassis compartment also compresses the acoustic barrier, as claimed in the appended claims.

[0011] According to an aspect of the present invention there is provided a vehicle acoustic barrier system fora vehicle chassis, the vehicle acoustic barrier system including:

[0012] a vehicle chassis compartment enclosing a volume, the vehicle chassis compartment having a first interior wall portion circumscribing a portion of the volume; and

[0013] a self-supporting body configured to locate in a located position within the vehicle chassis compartment such that the self-supporting body spans the portion;

[0014] wherein the self-supporting body includes a perimeter portion extending around the self-supporting body; and

[0015] wherein the perimeter portion is configured, in the located position, to provide an interference fit around the first interior wall portion.

[0016] In this way, the vehicle acoustic barrier system prevents noise from entering the vehicle chassis compartment. Noise pathways into the vehicle chassis compartment are blocked by the system. For example, the vehicle acoustic barrier system prevents noise from entering the vehicle underfloor area. Noise pathways for air-borne noise from the engine compartment or the tyres are blocked. Air-borne noise within the vehicle cabin is reduced.

[0017] According to another aspect of the invention, there is provided an acoustic barrier for mounting in a vehicle chassis compartment that encloses a volume, the vehicle chassis compartment having a first interior wall portion circumscribing a portion, the acoustic barrier including:

[0018] a self-supporting body configured to locate within the compartment in a located position so as to span the portion; and

[0019] a perimeter portion extending around the self-supporting body;

[0020] wherein the perimeter portion is configured, in the located position, to provide an interference fit around the first interior wall portion.

[0021] In this way, the acoustic barrier is easily installed during assembly of the vehicle chassis. The acoustic barrier is installed conveniently by locating the acoustic barrier at an entrance to the vehicle chassis compartment without intricate fitting. The acoustic barrier may be a formed as a single body that is easily handled and manipulated into the position.

[0022] According to yet another aspect of the invention, there is provided a vehicle chassis including a vehicle acoustic barrier system as described here.

[0023] According to a further aspect of the invention, there is provided a vehicle including a vehicle chassis including the vehicle acoustic barrier system as described here.

[0024] According to a further aspect of the invention, there is provided a method of assembling a vehicle acoustic barrier system including:

[0025] providing a first vehicle chassis panel and a second vehicle chassis panel, the first vehicle chassis panel and second vehicle chassis panel configured to be assembled to define a vehicle chassis compartment enclosing a volume;

[0026] providing an acoustic barrier having a self-supporting body and a perimeter portion extending around the self-supporting body, wherein the self-supporting body is configured to span a portion of the volume;locating a first length of the perimeter portion in contact with the first vehicle chassis panel; locating the second vehicle chassis panel in contact with a second length of the perimeter portion; and

[0027] urging the second vehicle chassis panel towards the first vehicle chassis panel to form the vehicle chassis compartment and compress the perimeter portion within a first interior wall portion of the vehicle chassis compartment.

[0028] In this way, the vehicle acoustic barrier system is installed more quickly because no additional fitting steps are required. Instead, the vehicle acoustic barrier system may be installed with the vehicle cabin panels using known methods of assembly. The vehicle acoustic barrier system is installed without modification to the vehicle chassis panels because it is configured to fit with the contoured profile shapes of existing parts. Optionally, the perimeter portion may be resiliently compressible. Optionally, the perimeter portion may be configured to, in the located position, conformingly seal around the first interior wall portion. In these ways, the perimeter portion may deform according to any tolerances in the perimeter portion or first interior wall portion while still ensuring a consistent interference fit. An interference fit around the entire first interior wall portion is ensured.

[0029] Optionally, the perimeter portion may have a contoured profile shape. Optionally, the first interior wall portion may have a contoured profile shape. Optionally, the perimeter portion and the first interior wall portion may each have mutually-contoured profile shapes. In these ways, the perimeter portion is adapted to undulations and formations in the vehicle chassis panels.

[0030] Optionally, in the located position, a region of the self-supporting body and a region of the first interior wall portion may together define an entrance to the vehicle chassis compartment. The self-supporting body may include a closure element configured to be selectively moved between a first orientation, in which the entrance is open, and a second orientation, in which the entrance is closed.

[0031] Optionally, a region of the self-supporting body may include a cut-out portion extending into the self-supporting body from the perimeter portion. In the located position, the cut-out portion and the region of the first interior wall portion may define an entrance to the vehicle chassis compartment. In this way, the acoustic barrier is installed easily around elongate members, and then readily manipulated to fit around the elongate members.

[0032] Optionally, the closure element may include at least one formation on an outer edge. The at least one formation may be a channel extending inwards from the outer edge of the closure element. The, or each, channel may be configured so that, as the closure element is between the first orientation and the second orientation, the channel is guided along an elongate member of the vehicle chassis extending into the vehicle chassis compartment via the entrance.

[0033] In these ways, the vehicle acoustic barrier system may be adapted to function with other members of the vehicle chassis or vehicle sub-systems. The acoustic barrier is capable of being fitted in conjunction with elongate members that pass through the vehicle chassis compartment. Again, the acoustic barrier is adaptable to enable installation without modification of other aspects of the vehicle chassis. Once installed, the acoustic barrier blocks potential noise pathways around the elongate members.

[0034] Optionally, the channel may include a seal element. The seal element may be configured so that, in the second orientation, the seal element conformingly seals around the elongate member. In an example, a sealelement may be formed as a flange at the edge of a channel. In this way, each seal element conforms around the respective elongate member as the elongate member is received into the channel. In an example, a seal element may be formed as a ridged surface extending between the inner face and the outer face of the acoustic barrier. In this way, the seal element may conform around a plurality of elongate members aligned closely together. The seal element also provides means to block potential noise pathways through an empty channel, after the elongate member has been guided along the channel.

[0035] Optionally, the closure element may be mounted to the self-supporting body. The closure element may be configured to be selectively moved between the first orientation and the second orientation by folding about a hinge element. Optionally, the closure element may be integrally formed with the self-supporting body. In these ways, the closure element may be manufactured with the rest of the self-supporting body. In particular, the closure element may formed with the self-supporting body.

[0036] Optionally, the self-supporting body may include an inner face, oriented towards the vehicle chassis compartment. The self-supporting body may include an opposing outer face. The self-supporting body may include a body extending between a pair of end portions.

[0037] Optionally, the self-supporting body may include a rigid frame member embedded within a compressible matrix. Optionally, a retainer may be integrally formed with the rigid frame member. Optionally, the rigid frame may be formed of a thermoplastic material, for example polypropylene, acrylonitrile butadiene styrene (ABS), or nylon.

[0038] In these ways, the self-supporting body may be provided with a lightweight, resilient support. The self-supporting body may be formed using known moulding techniques.

[0039] Optionally, the compressible matrix may be formed of a polymeric foam material. Optionally, the polymeric foam material may be a polyurethane, for example a high-density polyurethane. The polyurethane may have a density in a range of from 50 kilograms per cubic metre to 200 kilograms per cubic metre, or in a range of from 100 kilograms per cubic metre to 150 kilograms per cubic metre.

[0040] In these ways, the compressible matrix may be easily formed around a support, such as a rigid frame member. By using a suitable compressible matrix, the degree of compression of the perimeter portion may be adapted according to the dimensions and profile shape of the vehicle chassis compartment to ensure a reliable interference fit.

[0041] Optionally, the compressible matrix may include a continuous external layer. In this way, the continuous external layer provides a surface that reflects noise away from the self-supporting body. Additionally, the continuous external layer provides a protective surface to the self-supporting body, preventing ingress of contamination into the matrix.

[0042] Optionally, the continuous external layer may be integrally with the compressible matrix of the self-supporting body. For example, the continuous external layer may be formed of a polyurethane material.

[0043] Optionally, the continuous external layer may be applied onto the self-supporting body after the self-supporting body has been formed. The continuous external layer may be formed of a heat-resistant material so as to provide protection to the self-supporting body from heated components of the vehicle chassis, such as an engine exhausts. In an example, the heat-resistant material is a metal foil, such as an aluminium foil.Optionally, the vehicle acoustic barrier system may include one or more baffle members. Optionally, a baffle member may be engaged with a portion of the inner face or the outer face of the self-supporting body, for example, a baffle member engaged with the outer face of each end portion. Each baffle member may be configured to conformingly engage a chassis surface oriented towards the outer face of the self-supporting body of the vehicle acoustic barrier system. Optionally, the chassis surface may be a wheel arch. Optionally, the baffle member may be a carrier cover mounted in the vehicle chassis to occupy space between the wheel arch and the compartment opening. Optionally, the self-supporting body and the baffle members may together span with width of the vehicle chassis.

[0044] In these ways, the vehicle acoustic barrier system may provide further noise mitigation because it occupies volumes or compartments beyond an entrance to a vehicle chassis compartment. By providing a close fit between a baffle member and another chassis surface, the acoustic barrier is positioned more securely within the vehicle chassis.

[0045] Optionally, the vehicle acoustic barrier system may include at least one retainer. The, or each, of the at least one retainer may be configured to engage a corresponding receiver to locate the acoustic barrier in the located position, wherein the receiver is disposed on the vehicle chassis. Optionally, the receiver may be an opening in a vehicle chassis panel, such as a vehicle cabin floor panel.

[0046] In these ways, the acoustic barrier may be held in position while the vehicle chassis compartment is formed around the acoustic barrier, without additional support or intervention.

[0047] Optionally, the at least one retainer may project from the perimeter portion of the self-supporting

[0048] body. Optionally, the at least one retainer may project from an upper region of the perimeter portion.

[0049] Optionally, at least one retainer may project from each end portion. Optionally, each at least retainer may be partially embedded in the self-supporting body and project through the perimeter portion of the self-supporting body. Optionally, the retainer may be integrally formed with the self-supporting body.

[0050] In these ways, the retainer is low cost and easy to manufacture with the acoustic barrier. The retainer may be readily adapted and oriented to fit to a range of receivers provided on the vehicle chassis panels.

[0051] Optionally, the vehicle chassis compartment may be defined by at least two vehicle chassis panels. One of the at least two vehicle chassis panels may be a vehicle cabin panel, for example the vehicle cabin panel may be a vehicle cabin floor panel. One of the at least two vehicle chassis panels may be an underbody protection panel.

[0052] Optionally, one of the at least two vehicle chassis panels may be a chassis outer wall panel. The chassis outer wall panel may be underbody protection panel. The underbody protection panel may be formed of plastic. The underbody protection panel may be fastened to the other vehicle chassis panel of the at least two vehicle chassis panels using a fastener, for example a bolt.

[0053] Optionally, the vehicle chassis compartment may be an elongate compartment having a lengthways axis and a cross-sectional shape extending along the lengthways axis. The self-supporting body may span the portion of the volume at the first interior wall portion transverse to the lengthways axis. The self-supporting body may span the volume across the width of the vehicle chassis.

[0054] Optionally, the method may include a step of fastening the second vehicle chassis panel to the first vehicle chassis panel. In this way, the acoustic barrier is secured within the first interior wall portion during typical assembly of the vehicle chassis panels.Optionally, the self-supporting body may include a retainer, and the method may include a step of locating a first length of the perimeter portion in contact with the first vehicle chassis panel further includes engaging the retainer with a mutually-configured receiver in the vehicle chassis compartment. In this ways, the acoustic barrier may be held in position while the vehicle chassis compartment is formed around the acoustic barrier, without additional support or intervention.

[0055] Optionally, the method may include a step of compressing the perimeter portion within a first interior wall portion of the vehicle chassis compartment to provide a compression of the self-supporting body. Optionally, the compression may be in a range of from 2 millimetres to 5 millimetres. In these ways, the perimeter portion may be deformed to ensure a consistent interference fit around the entire first interior wall portion. The acoustic barrier blocks all noise pathways into or out of the vehicle chassis compartment.

[0056] As used herein, “self-supporting" means that an element or component maintains its shape without any supporting structures or reinforcements that are external to, or extraneous of, the element or component itself. In an example, a self-supporting body includes a rigid frame member embedded with a body formed of compressible matrix so that the rigid frame member supports the compressible matrix from within.

[0057] As used herein, “span” means to bridge a space or opening between elements such as walls, surfaces, or portions of walls and surfaces. Typically, the element that is spanning a space or opening will provide a closure to the space or opening.

[0058] As used herein, “mutually-contoured profile shape” means that elements that abut one another, for example a perimeter portion and a first interior wall portion, each have profile shape that is complementary to the other. The complementary profile shapes may include a series of formations that are shaped to correspond with one another in order that the elements maintain contact along the length of the abutting surfaces.

[0059] Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner.

[0060] BRIEF DESCRIPTION OF THE DRAWINGS

[0061] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0062] FIG. 1 shows a cross-sectional view of a schematic of a vehicle acoustic barrier system in accordance with an embodiment of the invention;

[0063] FIG. 2A shows a front view of a vehicle acoustic barrier system in accordance with an embodiment of the invention;

[0064] FIG. 2B shows a perspective view of the system of FIG. 2A;

[0065] FIG. 2C shows a perspective view of the acoustic barrier of system of FIG. 2A;

[0066] FIG. 3A shows a cross-sectional view of a schematic of an example vehicle chassis compartment; FIG. 3B shows a cross-sectional view of a schematic of another vehicle acoustic barrier system in accordance with an embodiment of the invention, mounted in the vehicle chassis compartment of FIG. 3A;FIG. 3C shows the vehicle acoustic barrier system of FIG. 3A in a second orientation;

[0067] FIG. 4A shows a perspective view of another acoustic barrier in accordance with an embodiment of the invention, engaged with elongate members;

[0068] FIG. 4B shows a close up perspective view of a portion of FIG. 4A;

[0069] FIG. 4C shows an alternative perspective view of the acoustic barrier and elongate members of FIG.

[0070] 4A;

[0071] FIG. 5A shows a cross-sectional view of a schematic of a further vehicle acoustic barrier system in accordance with an embodiment of the invention;

[0072] FIG. 5B shows a top view of the acoustic barrier of FIG. 5A;

[0073] FIG. 6A shows a close up perspective view of a portion of the acoustic barrier of FIG. 2C;

[0074] FIG. 6B shows a lower perspective view of the acoustic barrier of FIG. 2C engaged with a vehicle chassis panel;

[0075] FIG. 7 shows a flow diagram of the steps of a method of assembling a vehicle acoustic barrier system according to an embodiment of the invention; and

[0076] FIG. 8 shows a chart with data measuring air-borne noise with and without a vehicle acoustic barrier system according to an embodiment of the invention.

[0077] DETAILED DESCRIPTION

[0078] Certain terminology is used in the following description for convenience only and is not limiting. The words ‘inner’ and ‘outer’ referto directions toward and away from, respectively, a designated centreline ora geometric centre of an element being described (e.g. central axis), the particular meaning being readily apparent from the context of the description.

[0079] Further, as used herein, the terms ‘attached’, ‘coupled’, ‘mounted’ are intended to include direct connections between two members without any other members interposed therebetween, as well as, indirect connections between members in which one or more other members are interposed therebetween. The terminology includes the words specifically mentioned above, derivatives thereof, and words of similar import.

[0080] Further, unless otherwise specified, the use of ordinal adjectives, such as, ‘first’, ‘second’, ‘third’ etc. merely indicate that different instances of like objects are being referred to and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking or in any other manner.

[0081] With reference to FIG. 1 to FIG. 2C, there is shown a vehicle acoustic barrier system 100 for use in a vehicle chassis in accordance with an embodiment of the present invention.

[0082] The vehicle acoustic barrier system 100 includes a vehicle chassis compartment 140 enclosing a volume 142. The vehicle chassis compartment 140 is defined by two vehicle chassis panels. In the example shown, a first vehicle chassis panel is a vehicle cabin floor panel 146. The second vehicle chassis panel is a chassis outer wall panel 148, in particular the chassis outer wall panel 148 is an underbody protection panel, formed of plastic and fastened to the vehicle cabin floor panel 146 using a series of bolts. The vehicle chassis compartment 140 is positioned below the vehicle cabin.

[0083] The chassis outer wall panel 148 is assembled to the vehicle cabin floor panel 146 to form the walls of the vehicle chassis compartment 140. The vehicle cabin floor panel 146 and chassis outer wall panel 148 areshaped to define an entrance 105a to the vehicle chassis compartment 140 at one end of the vehicle chassis compartment 140. In the example, the entrance 105a is proximal to the engine compartment of the vehicle. The vehicle chassis compartment 140 has a first interior wall portion 144 circumscribing a portion 143 of the volume 142. The first interior wall portion 144 includes a upper section and a lower section. The upper section of the first interior wall portion 144 is formed from the vehicle cabin floor panel 146. The lower section of the first interior wall portion 144 is formed from the vehicle cabin floor panel 146. With the chassis outer wall panel 148 assembled to the vehicle cabin floor panel 146, the upper section and lower section form a continuous first interior wall portion 144 around a proximal end of the vehicle chassis compartment 140.

[0084] A self-supporting body 101 is configured to locate in a located position within the vehicle chassis compartment 140 such that the self-supporting body 101 spans the portion 143 of the volume 142. The self-supporting body 101 is an acoustic barrier 110, shown in more detail in FIG. 2C. By spanning the portion 143 of the volume 142, the acoustic barrier 110 extends across the entrance 105a of the vehicle chassis compartment 140. The entrance 105a is capped by the acoustic barrier 110.

[0085] With particular reference to FIG. 2C, the acoustic barrier 110 has an inner face 111 , arranged to be oriented towards the vehicle chassis compartment 140. That is, in use, in the located position, the inner face 111 forms an end wall of the vehicle chassis compartment 140. The acoustic barrier 110 also includes an outer face 112. The outer face 112 is arranged in opposition to the inner face 111 so that, in use, the outer face 112 is exposed outside of the vehicle chassis compartment 140.

[0086] The acoustic barrier 110 has a body 123 extending between a pair of end portions 121. The body 123 is formed as an elongate plate with a thickness between its inner face 111 and its outer face 112. The body 123 has a substantially uniform thickness.

[0087] A perimeter portion 122 extends around the acoustic barrier 110. The perimeter portion 122 has an inner edge circumscribing the inner face 111 , and an outer edge circumscribing the outer face 112. The perimeter portion 122 has a width between its inner and outer edges corresponding to the thickness of the body 123. The width of the perimeter portion 122 is substantially uniform around the body 123.

[0088] The perimeter portion 122 has a contoured profile shape. That is, the perimeter portion 122 includes a series of formations extending in to, or projecting out from, the body 123. The formations provide a contoured profile shape corresponding to the profile shape of the first interior wall portion 144. In this way, the vehicle acoustic barrier system includes the perimeter portion and the first interior wall portion each have mutually-contoured profile shapes.

[0089] In one example of the profile shape, the formations on the body 123 include a series of recesses and channels 130 along its upper edge. The recesses conform to ridges on the vehicle cabin floor panel 146 and chassis outer wall panel 148 at the first interior wall portion 144. The channels 130 conform to elongate members 160 extending through the entrance 105a and into the vehicle chassis compartment 140, as described in more detail with reference to FIG. 3A to FIG. 4C.

[0090] In another example of the profile shape, the perimeter portion 122 is angled to correspond with the angled of surfaces on the first interior wall portion 144. In certain sections of the perimeter portion 122, the inner edge and the outer edge overlie one another, so that the perimeter portion is oriented at a perpendicular to each of the inner face 111 and the outer face 112. In certain positions of the perimeter portion 122, one of the inneredge or the outer edge extends outward, beyond the other edge, so that the perimeter portion is oriented at an angle to the perpendicular.

[0091] By including features of both the examples of the profile shape, the self-supporting body 101 is shaped to fit within the entrance 105a of the vehicle chassis compartment 140 to seal against the first interior wall portion 144. The perimeter portion 122 is configured so that, in the located position, the perimeter portion 122 abuts the first interior wall portion 144. In these ways, the perimeter portion 122 provides an interference fit around the first interior wall portion 144. The interference fit provides a tight enough seal between the body 123 and the first interior wall portion 144 to close off noise pathways for airborne noise into the vehicle chassis compartment 140 through the entrance 105a.

[0092] As will be apparent, each example of the profile shape is not reliant upon the other example of the profile shape and each example may be used independently of the other, or may be combined with other suitable formations on the perimeter portion, in order to conform to a profile shape on the first interior wall portion. The self-supporting body 101 of the acoustic barrier is formed from a polymeric foam material matrix. In the example, the polymeric foam material is a polyurethane foam material having a density in a range of from 100 kilograms per cubic metre to 150 kilograms per cubic metre.

[0093] The matrix is a compressible matrix with a continuous external layer, or skin, forming an outer protective layer to the foam material. In this way, the perimeter portion 122 is resiliently compressible as it is urged into the interference fit with the first interior wall portion 144. The perimeter portion 122 deforms in order to conform to minor defects or tolerances in the profile shape of the first interior wall portion 144.

[0094] The self-supporting body 101 includes a rigid frame member embedded within the matrix. The rigid frame member provides a support to the matrix, increasing the rigidity of the self-supporting body 101. The rigid frame member is formed of a thermoplastic material, in the example a polypropylene material.

[0095] In the example, the self-supporting body is formed, in a first step, by injection-moulding the rigid frame member, and then, in a second step, by co-moulding the matrix onto the rigid frame member.

[0096] The body 123 of the acoustic barrier 110 also includes a closure element 120, the details of which are described now with reference to FIG. 3A to FIG. 4C. The closure element 120 is formed in the body 123 to enable the acoustic barrier 110 to be fitted to the first interior wall portion 144 while accommodating other vehicle components that pass through the vehicle chassis compartment 140.

[0097] As shown in FIG. 3A, the vehicle chassis compartment 140 includes a series of elongate members 160 passing through the entrance 105a and into the vehicle chassis compartment 140. The elongate member 160 may be, for example, coolant pipes or conduits of electrical cables.

[0098] The body 123 includes a cut-out portion 118 extending into the body 123 from an upper region of the its perimeter portion 122. With the acoustic barrier 110 in the located position and the closure element 120 in a first orientation (FIG. 3B), the cut-out portion 118 (see, for example FIG. 4A) and a region of the first interior wall portion 144 define an entrance 105b into the vehicle chassis compartment for the elongate members 160.

[0099] The closure element 120 is mounted to the cut-out portion 118 by a hinge element 126. The hinge element 126 enables the closure element 120 to be selectively moved between the first orientation and a second orientation by folding the closure element 120 about the hinge element 126. Referring particularly to FIG. 3B and FIG. 3C, the closure element 120 moves between a first orientation (FIG. 3B), in which the closureelement 120 is hinged away from the cut-out portion 118 (shown particularly in FIG. 2C), and the second orientation (FIG. 3C), in which the closure element 120 is located within the cut-out portion 118. Thus, in the first orientation, the entrance 105b is open, and in the second orientation, the entrance 105b is closed. Referring additionally to FIG. 4A to FIG. 4C, there is shown the acoustic barrier 110 and elongate members 160 in the second orientation, without the panels forming the vehicle chassis compartment 140.

[0100] The closure element 120 includes a series of channels 130 extending inwards from the perimeter portion 122 on the closure element. Each channel 130 is configured so that, as the closure element 120 is moved from the first orientation to the second orientation, the channel 130 is guided along an elongate member 160. Each channel 130 terminates at a corresponding inner end. The inner end is positioned on the closure element 120 so that, in the second orientation, the inner end coordinates with the lengthways axis of the elongate member 160 that is received by the channel 130. In this way, the elongate member 160 rests snugly at the inner end of the channel 130.

[0101] Certain channels 130 include a seal element 128a, 128b, as shown particularly in FIG. 6A. Each seal element 128a, 128b conformingly seals around an elongate member 160 when the closure element 120 is in the second orientation.

[0102] In the example, a first seal element 128a is formed as a flange at the edge of the channel 130 proximal to the outer face 112. In this way, each seal element 128a conforms around the respective elongate member 160 as the elongate member 160 is received into the channel 130.

[0103] In the example, a second seal element 128b is formed as a ridged surface extending between the inner face 111 and outer face 112 of the acoustic barrier 110. In this way, the seal element 128b conforms around a plurality of elongate members 160 aligned closely together.

[0104] With reference to FIG. 5A and FIG. 5B, there is shown a vehicle acoustic barrier system 200 for use in a vehicle chassis in accordance with another embodiment of the present invention.

[0105] The vehicle acoustic barrier system 200 includes acoustic barrier 201 configured to locate in a located position within a vehicle chassis compartment 240 enclosing a volume 242, in a similar manner to the vehicle acoustic barrier system 100 described with reference to FIG. 1 to FIG. 4C.

[0106] The acoustic barrier 201 has a body 223 extending between a pair of end portions 221. The body 223 is formed as an elongate plate with a thickness between its inner face 211 and its outer face 212. The body 223 has a substantially uniform thickness.

[0107] A perimeter portion extends around the acoustic barrier 201. The perimeter portion has a contoured profile shape, including a series of formations extending in to, or projecting out from, the body 223. The formations provide a contoured profile shape corresponding to the profile shape of the first interior wall portion 244. The vehicle acoustic barrier system 200 includes a baffle member 232 engaged with the outer face of each end portion 221 . In the example, each baffle member 232 is a carrier cover mounted in the vehicle chassis to occupy space between the wheel arch and the compartment opening. The baffle member 232 is hollow body that is separable from the acoustic barrier 201.

[0108] Each baffle member 232 is configured to conformingly engage a chassis surface 290 oriented towards the outer face. In the example, the chassis surface 290 is a surface of a wheel arch. In this way, with the acoustic barrier 201 in the located position in the vehicle chassis compartment 240, the baffle members 232engage respective wheel arches, and occupy the space between the wheel arch and the vehicle chassis compartment 240. The baffle members 232 further close off noise pathways for airborne noise from the vehicles wheels to the vehicle chassis compartment 240, further improving the acoustic barrier performance. In an alternative arrangement, each baffle member may be integrally formed with the acoustic barrier. Each baffle member may be formed of a portion of the compressible matrix of the acoustic barrier. A portion of the rigid frame member may be embedded within the compressible matrix within the baffle member to ensure that each baffle member is self-supporting.

[0109] With reference to FIG. 6A and FIG. 6B, there is shown a close up view of the vehicle acoustic barrier system 100 described above. In particular, there is shown an end portion 121 having a retainer 134 mounted to the end portion 121. While one end portion 121 is shown, it will be apparent that the opposing end portion 121 also includes a corresponding retainer 134.

[0110] The retainer 134 includes a pair of deformable prongs of a clip mounted to the end portion 121 and extending from the perimeter portion 122. The retainer 134 is oriented so that its prongs project upwards from the end portion 121.

[0111] The retainer 134 is configured to engage a corresponding receiver 106 disposed on the vehicle chassis. In the example, the receiver 106 is an opening through the vehicle cabin floor panel 146 of the vehicle chassis, to locate the acoustic barrier in the located position.

[0112] To use the retainer 134, each retainer 134 is aligned with a corresponding 106, and the acoustic barrier 110 is pushed upwards against the vehicle cabin floor panel 146. The prongs are deformed, to allow the retainer 134 to be received by the receiver 106, and then as the prongs are received beyond the distal surface of the receiver 106, to recover their shape and retain the retainer 134.

[0113] It will be noted that the length of the retainer 134 may be configured to control the interference fit of the acoustic barrier 110 against the first interior wall portion 144. In particular, the retainer 134 may be configured to determine the amount of compression applied to the upper section of the perimeter portion 122 by the first interior wall portion 144 once the retainer 134 is retained against the distal surface of the receiver 106.

[0114] Referring now to FIG. 7, there is shown a schematic of a method of assembling a vehicle acoustic barrier system according to an embodiment of the invention.

[0115] In a first step 702, the method includes providing a first vehicle chassis panel and a second vehicle chassis panel. The first vehicle chassis panel and the second vehicle chassis panel are configured to be assembled to define a vehicle chassis compartment enclosing a volume. The volume may be, for example, the volume 142 of the vehicle chassis compartment 140 defined within the first interior wall portion vehicle cabin floor panel 146 and chassis outer wall panel 148, such as an underbody protection panel, described above.

[0116] In a second step 704, the method includes providing an acoustic barrier having a self-supporting body and a perimeter portion extending around the self-supporting body, wherein the self-supporting body is configured to span a portion of the volume. The portion may be, for example the portion 143 circumscribed by the first interior wall portion 144 described above.

[0117] In a third step 706, the method includes locating a first length of the perimeter portion in contact with the first vehicle chassis panel. The first length of the perimeter portion may be a perimeter portion of the upper section of an acoustic barrier located against the vehicle cabin floor panel 146.Optionally, locating the first length of the perimeter portion may also include engaging the retainer with a mutually-configured receiver in the vehicle chassis compartment, for example locating the retainer 134 within the receiver 106 described with reference to FIG. 6A and FIG. 6B. In this way, the first length of the perimeter portion may be compressed as the retainer is engaged with the receiver.

[0118] In a fourth step 708, the method includes locating the second vehicle chassis panel in contact with a second length of the perimeter portion. The second vehicle chassis panel may be the chassis outer wall panel 148, which is assembled to the vehicle cabin floor panel 146 to form the vehicle chassis compartment 140.

[0119] In a fifth step 710, the method includes urging the second vehicle chassis panel towards the first vehicle chassis panel to form the vehicle chassis compartment and compressing the perimeter portion within a first interior wall portion of the vehicle chassis compartment. The first interior wall portion may be the first interior wall portion 144 formed by portions of the vehicle cabin floor panel 146 and chassis outer wall panel 148 described above.

[0120] Optionally, the method includes a step of fastening the second vehicle chassis panel to the first vehicle chassis panel. For example, the chassis outer wall panel 148 is an underbody protection panel formed of plastic and fastened to the vehicle cabin floor panel 146 by a series of bolts. Fastening the chassis outer wall panel 148 to the vehicle cabin floor panel 146 fixes the configuration of the first interior wall portion 144. In this way, the compression of the perimeter portion is fixed, holding the acoustic barrier in place within the first interior wall portion 144.

[0121] Optionally, the step of compressing the perimeter portion within a first interior wall portion of the vehicle chassis compartment provides a compression of the self-supporting body in a range of from 2 millimetres to 5 millimetres. That is, the compression at different locations around the perimeter portion of an example acoustic barrier may each be a value in the range of from 2 millimetres to 5 millimetres. In this way, the compression around the perimeter portion may vary depending on tolerances between contacting surfaces while always being sufficient to ensure an effective interference fit.

[0122] As will be apparent, the method may be used with an acoustic barrier having a closure element, such as a hinged closure element. In this way, the method may be implemented with the closure element in a first orientation, in which the closure element is hinged away from the cut-out portion. That is, an entrance to the vehicle chassis compartment is open. A further step of the method then requires moving the closure element from the first orientation to a second orientation, in which the closure element is located within the cut-out portion. In the second orientation, the entrance is closed. In this way, the method enables simple and quick installation of the acoustic barrier which seals around both the compartment opening and any elongate members passing through the compartment opening.

[0123] Referring now to FIG. 8, there is shown a chart illustrating air-borne noise measured under test conditions with and without a vehicle acoustic barrier system according to an embodiment of the invention.

[0124] To test the performance of a vehicle acoustic barrier system, a test vehicle is subjected to measurement of acoustic transfer functions in a semi-anechoic room, that is a test room in which sound reflections only come from the floor. The room has a Noise Rating (NR) of 20 or less. The test method uses a noise signal generator including a low frequency sound source and high frequency sound source, to determine noise levels at an occupant's, particularly a driver's, ear position in the vehicle cabin. Accordingly, sound is emitted from the noise signal generator across frequencies in a range of from 500 Hertz to 6,300 Hertz.The noise signal generator is mounted to a front seat within the vehicle cabin, corresponding to a position of an occupant's ear position. A series of microphones are mounted within the engine compartment of the vehicle chassis. In particular, twelve microphones are positioned around the power unit within the engine compartment. Two microphones are mounted on each face of the power unit

[0125] Noise signal data received through the microphones is acquired and converted to a frequency response function (FRF) using SimcenterTest Lab software with the following acquisition parameters:

[0126]

[0127] During testing, data is inspected for quality before being stored. Measurements made using the low frequency sound source are validated to ensure yield FRFs with good coherence (>70%) between 30 Hertz and 800 Hertz according to predetermined coherence standard. Measurements made using the high frequency sound source are validated to ensure good coherence (>70%) between 800 Hertz and 6,500 Hertz according to predetermined coherence standards. To validate that the noise signal generators and the microphones are operating correctly, the Autopower spectra produced under the test was also inspected.

[0128] The described test was conducted with a test vehicle, in a first condition, without an acoustic barrier between the vehicle cabin and the engine compartment and, in a second condition, with the vehicle acoustic barrier system including the self-supporting body 101 installed in the compartment underneath the vehicle cabin floor panel, as described above. The self-supporting body 101 is formed of a polyurethane foam material having a density in a range of from 100 kilograms per cubic metre to 150 kilograms per cubic metre moulded onto a rigid frame member formed of a polypropylene material.

[0129] The measured responses of the test vehicle under the two test conditions are shown on the chart 800. A first response 801 shows the measure noise signal across a range of sound frequencies without the vehicle acoustic barrier system installed. As a result, the test vehicle includes a noise pathway from the engine compartment to the vehicle cabin through the underfloor compartment. A second response 802 shows the measure noise signal across a range of sound frequencies with the vehicle acoustic barrier system installed. As a result, the test vehicle includes a barrier to the noise pathway from the engine compartment to the vehicle cabin through the underfloor compartment. Under the test conditions described, the vehicle acoustic barrier system provides an attenuation of up to 4 decibels at specific frequencies within the test range. The vehicle acoustic barrier system provides an attenuation averaging approximately 2 decibels across the frequency range of the test. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS1. A vehicle acoustic barrier system for a vehicle chassis, the vehicle acoustic barrier system comprising: a vehicle chassis compartment enclosing a volume, the vehicle chassis compartment having a first interior wall portion circumscribing a portion of the volume; anda self-supporting body configured to locate in a located position within the vehicle chassis compartment such that the self-supporting body spans the portion;wherein the self-supporting body comprises a perimeter portion extending around the self-supporting body; andwherein the perimeter portion is configured, in the located position, to provide an interference fit around the first interior wall portion.

2. The vehicle acoustic barrier system of claim 1 , wherein the perimeter portion is resiliency compressible.

3. The vehicle acoustic barrier system of claim 1 or 2, wherein the perimeter portion and the first interior wall portion each have mutually-contoured profile shapes.

4. The vehicle acoustic barrier system of any one of claims 1 to 3, wherein, in the located position, a region of the self-supporting body and a region of the first interior wall portion together define an entrance to the vehicle chassis compartment and, wherein the self-supporting body comprises a closure element configured to be selectively moved between a first orientation, in which the entrance is open, and a second orientation, in which the entrance is closed.

5. The vehicle acoustic barrier system of claim 4, wherein the region of the self-supporting body comprises a cut-out portion extending into the self-supporting body from the perimeter portion so that, in the located position, the cut-out portion and the region of the first interior wall portion define the entrance to the vehicle chassis compartment.

6. The vehicle acoustic barrier system of claim 4 or 5, wherein the closure element is mounted to the self-supporting body and is configured to be selectively moved between the first orientation and the second orientation by folding about a hinge element.

7. The vehicle acoustic barrier system of any one of claims 4 to 6, wherein the closure element is integrally formed with the self-supporting body.

8. The vehicle acoustic barrier system of any one of claims 4 to 7, wherein the closure element comprises at least one channel extending inwards from an outer edge of the closure element, and wherein the or each channel is configured so that, as the closure element is moved between the first orientation and the second orientation, the channel is guided along an elongate member of the vehicle chassis extending into the vehicle chassis compartment via the entrance.

9. The vehicle acoustic barrier system of claim 8, wherein the channel comprises a seal element configured so that, in the second orientation, the seal element conformingly seals around the elongate member.

10. The vehicle acoustic barrier system of any one of claims 1 to 9, wherein the self-supporting body comprises an inner face, oriented towards the vehicle chassis compartment, and an opposing outer face, and wherein the self-supporting body is a body extending between a pair of end portions.

11. The vehicle acoustic barrier system of claim 10, comprising a baffle member mounted to the outer face of each end portion, wherein each baffle member is configured to conformingly engage a chassis surface oriented towards the outer face.

12. The vehicle acoustic barrier system of any one of claims 1 to 11, comprising at least one retainer configured to engage a corresponding receiver to locate the self-supporting body in the located position, wherein the receiver is disposed on the vehicle chassis.

13. The vehicle acoustic barrier system of claim 12, wherein the retainer projects from the perimeter portion of the self-supporting body.

14. The vehicle acoustic barrier system of any one of claims 1 to 13, wherein the vehicle chassis compartment is defined by at least two vehicle chassis panels and wherein one of the at least two chassis panels is a vehicle cabin panel.

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