CA1073006A - Noise attenuating engine enclosure - Google Patents
Noise attenuating engine enclosureInfo
- Publication number
- CA1073006A CA1073006A CA240,656A CA240656A CA1073006A CA 1073006 A CA1073006 A CA 1073006A CA 240656 A CA240656 A CA 240656A CA 1073006 A CA1073006 A CA 1073006A
- Authority
- CA
- Canada
- Prior art keywords
- enclosure
- panel
- engine
- perforated area
- secondary panel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R13/00—Elements for body-finishing, identifying, or decorating; Arrangements or adaptations for advertising purposes
- B60R13/08—Insulating elements, e.g. for sound insulation
- B60R13/0838—Insulating elements, e.g. for sound insulation for engine compartments
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K11/00—Arrangement in connection with cooling of propulsion units
- B60K11/06—Arrangement in connection with cooling of propulsion units with air cooling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R13/00—Elements for body-finishing, identifying, or decorating; Arrangements or adaptations for advertising purposes
- B60R13/08—Insulating elements, e.g. for sound insulation
- B60R13/0884—Insulating elements, e.g. for sound insulation for mounting around noise sources, e.g. air blowers
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)
- Body Structure For Vehicles (AREA)
- Exhaust Silencers (AREA)
Abstract
NOISE ATTENUATING ENGINE ENCLOSURE
ABSTRACT
The internal combustion engine of a tractor is housed within an engine enclosure comprising a top panel and a pair of side panels. Each side panel is provided with a plurality of perforated areas to permit engine cooling air to flow between the inside and -the outside of the enclosure. A secondary panel is pro-vided for each perforated area and is disposed inside the enclo-sure in spaced relationship from its associated wall panel.
Each secondary panel is in registry with its associated per-forated area but is larger in area than its associated perfor-ated area, so that the edges of the secondary panel extend beyond the edges of the perforated area. This arrangement permits air to pass in or out of the enclosure in a path other than a straight line and serves to attenuate engine noise originating in the enclosure by preventing sound waves from passing in a direct path from the engine through the perfor-ated areas to the outside of the enclosure. One or more per-forated areas are provided in a fixed portion of the side panel as well as in a movable (hinged) portion of the side panel which opens to afford access to the interior of the engine enclosure.
ABSTRACT
The internal combustion engine of a tractor is housed within an engine enclosure comprising a top panel and a pair of side panels. Each side panel is provided with a plurality of perforated areas to permit engine cooling air to flow between the inside and -the outside of the enclosure. A secondary panel is pro-vided for each perforated area and is disposed inside the enclo-sure in spaced relationship from its associated wall panel.
Each secondary panel is in registry with its associated per-forated area but is larger in area than its associated perfor-ated area, so that the edges of the secondary panel extend beyond the edges of the perforated area. This arrangement permits air to pass in or out of the enclosure in a path other than a straight line and serves to attenuate engine noise originating in the enclosure by preventing sound waves from passing in a direct path from the engine through the perfor-ated areas to the outside of the enclosure. One or more per-forated areas are provided in a fixed portion of the side panel as well as in a movable (hinged) portion of the side panel which opens to afford access to the interior of the engine enclosure.
Description
This invention relates generally to engine enclosures for vehicles such as tractors or the like. In particular it relates to engine enclosures having perforated side panels for permitting ingress and egress of engine cooling air between the inside and outside of the enclosure and to means for attenuating engine noise from inside the enclosure.
In construction machinery such as tractors and simi-lar equipment employing large internal combustion engines it is common to house the engine within a protective engine enclo-sure. However, it is necessary in most cases to provide foringress and egress of large amounts of air into and out of the engine enclosure for engine cooling purposes. Accordingly, one or more panels, such as the side walls, of the engine enclosure are provided with perforations, louvers or other openings. Present federal regulations make it necessary to design such engine enclosures so that the sound level from the relatively noisy large engine therewithin is reduced or attenuated. The prior art offers many examples of sound atten-uating means for engine enclosures. In some instances the interior surfaces of the compartment are lined or covered with sound absorbing insulating materials. In other instances por-ous or louvered baffles made of sound absorbing material are arranged in the openings in the engine enclosure to permit necessary air flow while dampening the sound emanating from the enclosure. U.S. Patent 3,762,489 is an example of the latter type of arrangement.
In accordance with the present invention, an internal combustion engine of a vehicle such as a tractor is housed within an engine enclosure which is defined by a radiator at the front end of the tractor and by a plurality of primary panels defining the top, rear and opposite side walls of the enclosure. At least one of the primary panels, but preferably
In construction machinery such as tractors and simi-lar equipment employing large internal combustion engines it is common to house the engine within a protective engine enclo-sure. However, it is necessary in most cases to provide foringress and egress of large amounts of air into and out of the engine enclosure for engine cooling purposes. Accordingly, one or more panels, such as the side walls, of the engine enclosure are provided with perforations, louvers or other openings. Present federal regulations make it necessary to design such engine enclosures so that the sound level from the relatively noisy large engine therewithin is reduced or attenuated. The prior art offers many examples of sound atten-uating means for engine enclosures. In some instances the interior surfaces of the compartment are lined or covered with sound absorbing insulating materials. In other instances por-ous or louvered baffles made of sound absorbing material are arranged in the openings in the engine enclosure to permit necessary air flow while dampening the sound emanating from the enclosure. U.S. Patent 3,762,489 is an example of the latter type of arrangement.
In accordance with the present invention, an internal combustion engine of a vehicle such as a tractor is housed within an engine enclosure which is defined by a radiator at the front end of the tractor and by a plurality of primary panels defining the top, rear and opposite side walls of the enclosure. At least one of the primary panels, but preferably
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those two primary panels defining opposite side walls of the engine enclosure, are each provided with one or more perforated areas to permit engine cooling air flow between the inside and the outside of the enclosure. A secondary panel is provided for each perforated area and is disposed inside the enclosure in spaced relationship from its associated primary panel.
The secondary panel is in registry with its associated perfor-ated area but is larger in area than its associated perforated area so that the edges of the secondary panel extend beyond the edges of the perforated area. This arrangement permits engine cooling air to pass in or out of the enclosure in a path other than a straight line and serves to attenuate engine noise originating in the enclosure by preventing sound waves from passing in a direct path from the engine through th~
perforations to the outside of the enclosure.
In one embodiment of the invention the secondary panel is formed of solid, rigid non-acoustical material such as a metal plate. In a second embodiment the secondary panel is fabricated entirely of acoustical material. In a third embodiment the secondary panel comprises a support member of solid, rigid non-acoustical material in the form of a metal plate with a layer of acoustical material attached to that side of the support member which faces the engine.
A noise attenuating engine enclosure in accordance with the present invention provides for effective engine noise attenuation or reduction while permitting free flow of air either from inside the enclosure to the outside or vice versa.
Furthermore, an engine enclosure in accordance with the pres-ent invention is simple and economical to fabricate and install on a vehicle during manufacture or in the field. Fur-thermore, an engine enclosure in accordance with the present invention does not add significantly to the size of the ~073006 engine compartment and, in two embodiments, offers additional physical protection to the enyine and other components within the enclosure. One or more perforated areas are provided in a fixed portion of the side panel as well as in a movable (hinged) portion of the side panel which opens to afford access to the interior of the engine enclosure.
According to a further broad aspect of the present invention, there is provided an engine enclosure having a pri-mary panel with a perforated area defined by an imperforate outer boundary to permit air flow between the inside and outside of the enclosure. An imperforate secondary panel is disposed inside the enclosure and has an outer peripheral edge of the same general contour as the imperforate outer boundary of the perforated area and larger in area than the perforated areaO Means is also pro-vided for ~upporting the secondary panel in spaced overlapping relationship with the perforated area in a position normal to the path of air flow through the perforated area thereby defining a flow path to permit air flow through the perforated area and about the outer peripheral edge of the secondary panel while in-tercepting sound waves directed toward the secondary panel to attenuate engine noise originating inside the enclosure.
Figure 1 i9 a perspective view of a crawler tractor employing a noise attenuating engine enclosure in accordance with the invention:
Figure 2 is a top plan view of the tractor shown in Figure 1, Figure 3 is an enlarged side elevational view of the exterior side of the primary panel shown in Figures 1 and 2, Figure 4 is an elevational view taken on line 4-4 of Figure 3 and depicts diagrammatically the air flow path and the sound wave path at the edges of the secondary panel D
~073006 Figure 5 is an elevational view taken on line 5-5 of Figure 3, Figure 6 is a view similar to Figure 5 but showing a second type of secondary panel, and Figure 7 is a view similar to Figure 5 but showing a third type of secondary panel.
Referring to Figures 1 and 2, the numeral 10 desig-nates a crawler tractor having a chassis 12 on which an internal combustion engine 14 is mounted for driving the crawler tracks 16 and other power operated equipment mounted on the tractor in a conventional manner. The engine 14 is disposed within an engine enclosure 20 which generally comprises or is defined by a top wall 22, a rear end wall 24, a pair of side walls 26 and 28 on opposite lateral sides of the tractor 10 and a perforated radiator 30 at the front end of the _ 4a -C
107300~;
tractor. The engine is provided with a cooling fan 32 which draws air into the enclosure 20 through openings in the side walls 26 and 28 and expells the air through perforations in the radiator 30.
Figures 3, 4 and 5 show in detail the construction of the left side wall 28 of the enclosure 20. It is to be understood that the right side wall 26 of the enclosure 20 is similar to the left side wall 28 and, therefore, only the latter will be described in detail hereinafter. As Figure 3 shows, the side wall 28 comprises a first sheet metal section 34 which is rigidly secured to a suitable framework (not shown) which is understood to be rigidly mounted on the tractor chassis 12 and a second portion or wall panel 40 which is pivotably secured at its forward edge 12 to the first section 34 by an elongated hinge means 42. This arrangement enables panel 40 to be swung outwardly from a closed position (shown in the drawings) to an open position to afford access to the inside of the engine compartment. Suitable latch means 44 are pro-vided at the rear edge of panel 40 to lock the panel in closed position.
The wall panel 40 comprises a generally vertical upper section 46 and an integrally formed outwardly and down-wardly extending sloped lower section 48 to adapt the panel to the contour of the enclosure 20. The upper section 46 of panel 40 is provided with a plurality of holes or perforations 50 arranged in rows to provide a perforated area designated 52. The lower section 48 of panel 40 is provided with two such perforated areas 54 and 56, each containing a plurality of holes or perforations 50. The perforated areas 52, 54 and 56 permit cooling air to be drawn into or expelled from the inside of engine enclosure 20. Although circular holes 50 are shown, holes or perforations having other shapes could 1073(~06 be employed.
Since the perforated areas 54 and 56, if combined, would result in a relative long perforated area which would tend to weaken lower section 48 of panel 40, it is preferred to leave an unperforated strengthening region 51 therebetween.
In practice, it is preferred that panel 40 be fab-ricated with large cutout areas corresponding in shape to the perforated areas designated 52, 54 and 56 and to weld per-forated sheet metal on the inside of panel 40 so as to overlie the large cutout areas and thereby provide corresponding perforated areas. In Figure 3 the lines designated by the numberal 60 indicate the edges of the large cutouts on panel 40 and also correspond to the outer boundaries or edges of the perforated areas 52, 54 and 56. Figure 4 shows a perfor-ated member 53 which corresponds to or defines the perforated area 52 shown in Figure 3.
Panel 40 is hereinafter referred to in some instances as primary panel 40 to distinguish it from the two secondary panels 62 and 66 associated with the perforated areas 52 and 54, 56, respectively, associated therewith.
Referring to Figures 3, 4 and 5, each secondary panel 62 and 66 conforms in its general contour or outline to the shape of the perforated area 52 and 54, 56, respectively, with which it is associated. However, each secondary panel is larger in area than its associated perforated area or areas so that the edges of the secondary panel project beyond the edges 60 of the perforated area when the secondary panel is associated with the primary panel, as Figure 3 best shows.
The secondary panel 62 is supported in a fixed position with respect to and in spaced apart relationship from the inner side of primary panel 40 in reqistry with perforated area 52, as Figures 3 and 4 show. The secondary panel 66 is supported in a fixed position with respect to and in spaced apart relationship from the inner side of primary panel 40 in registry with perforated areas 54 and 56, as Figures 3 and 5 show.
Means are provided to rigidly support each secondary panel in the proper position with respect to its associated perforated area or areas. As Figures 3, 4 and 5 show, such means comprises brackets 70 welded to the inner side of panel 40 near a corner or an end of a secondary panel. The fasten-ing means further comprises bolts 72, each of which extendsthrough a hole 74 in an associated secondary panel and through a hole 76 in an associated bracket 70. A nut 75 screws onto the end of each bolt 72 to rigidly secure the secondary panel to an associated bracket 70. Secondary panel 62 employs three generally U-shaped support brackets 70, whereas secondary panel 66 employs two separate brackets 70, one of which is U-shaped and the other of which is generally L-shaped. In an actual embodiment of the present invention the perforated area 52 was on the order of 28 inches long, 20.4 inches high at the rear edge, 13.2 inches high at the forward edge. The distance between the inside surface of the primary panel and the outwardly facing surface of the secondary panel was on the order of 2-1/2 inches. The secondary panel was fabricated of 16-gauge sheet metal. Each edge of the secondary panel extended beyond the edge of its associated perforated area for a distance of at least approximately ]/2 inch.
Referring to Figures 4 and 5, it is apparent that each perforated area of a primary panel and its associated secondary panel are flat.
In the embodiment shown in Figure 5 the secondary panel 66 is fabricated of a solid, rigid non-acoustical mater-ial such as sheet steel having upturned outer edges. In the 1~373006 embodiment shown in Figure 6 the secondary panel 66A comprises a so:Lid, rigid sheet of non-acoustical material, such as panel 66, to the inner side of which (i.e., that side which faces engine 14) is bonded an acoustical material such as fiberglass insulating material, such as panel 66B. In the embodiment shown in Figure 7 the secondary panel 66B is fabri-cated of a rigid acoustical material such as polyurethane foam.
Referring to Figure 4, the arrows A depict the path of air flow from outside the engine compartment 20 to the inside therof when the engine 14 is operating to drive the radiator fan 32 to expel air outwardly through radiator 30.
As Figure 4 shows, the incoming air flow must follow a non-linear path in order to pass through any of the holes 50 in the perforated area and around any edge of the secondary panel 62. Figure 4 also schematically depicts the path which would be followed by sound waves designated 76 emanating from a poin1: on the surface of the engine 14. The sound waves 76 emanate outwardly from a central point, but any point in the wave 76 must necessarily follow a straight path. Therefore, because of the location and arrangement of the secondary panels 62 and 66 with respect to the engine 14 and the per-forated areas 52, 54 and 56 in the primary panel 40, sound waves emanating from the engine 14 cannot proceed directly from the engine to the holes 50 in the perforated area.
Therefore, although engine noise is thus attenuated, there is no substantial interference with necessary air flow between the outside of the engine compartment 20 and the exterior thereof.
Although the present invention is shown as being applied to an engine compartment for a tractor 10, it is apparent that it could be employed with other apparatus, -including stationary apparatus, employing an engine and requir-ing and engine enclosure. Furthermore, although three dif-ferent types of secondary panels are disclosed, it is apparent that secondary panels made of materials other than those spec-ified could be employed in accordance with the invention. In addition, although panel 40 is shown as comprising three dis-crete perforated areas 52, 54 and 56, it is apparent that a lessor greater number of perforated areas could be employed in a panel in accordance with the present invention. It is also apparent that mounting means of a type other than that disclosed could be employed. It is also apparent that, although circular holes 50 are shown, holes of other shapes could be employed, such as holes formed in a grid or screen formed of interwoven stiff wire or holes taking the form of linear type louvers punched in sheet metal. Similarly, hinge means and latch means other than those disclosed for panel 40 could be employed. The term "acoustical material", as employed herein, is intended to refer to any material which has the characteristic of deadening or damping sound, such as fiberglass batts, plastic foam, woven or felted materials, or the like, which are suitable for use in a relatively high temperature environment. Also, as Figures 1 and 3 show, stationary section 34 of side wall 28 comprises perforated areas 55 which are similar to area 52 and which have second-ary panels 57 similar to secondary panel 66 associated therewith.
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those two primary panels defining opposite side walls of the engine enclosure, are each provided with one or more perforated areas to permit engine cooling air flow between the inside and the outside of the enclosure. A secondary panel is provided for each perforated area and is disposed inside the enclosure in spaced relationship from its associated primary panel.
The secondary panel is in registry with its associated perfor-ated area but is larger in area than its associated perforated area so that the edges of the secondary panel extend beyond the edges of the perforated area. This arrangement permits engine cooling air to pass in or out of the enclosure in a path other than a straight line and serves to attenuate engine noise originating in the enclosure by preventing sound waves from passing in a direct path from the engine through th~
perforations to the outside of the enclosure.
In one embodiment of the invention the secondary panel is formed of solid, rigid non-acoustical material such as a metal plate. In a second embodiment the secondary panel is fabricated entirely of acoustical material. In a third embodiment the secondary panel comprises a support member of solid, rigid non-acoustical material in the form of a metal plate with a layer of acoustical material attached to that side of the support member which faces the engine.
A noise attenuating engine enclosure in accordance with the present invention provides for effective engine noise attenuation or reduction while permitting free flow of air either from inside the enclosure to the outside or vice versa.
Furthermore, an engine enclosure in accordance with the pres-ent invention is simple and economical to fabricate and install on a vehicle during manufacture or in the field. Fur-thermore, an engine enclosure in accordance with the present invention does not add significantly to the size of the ~073006 engine compartment and, in two embodiments, offers additional physical protection to the enyine and other components within the enclosure. One or more perforated areas are provided in a fixed portion of the side panel as well as in a movable (hinged) portion of the side panel which opens to afford access to the interior of the engine enclosure.
According to a further broad aspect of the present invention, there is provided an engine enclosure having a pri-mary panel with a perforated area defined by an imperforate outer boundary to permit air flow between the inside and outside of the enclosure. An imperforate secondary panel is disposed inside the enclosure and has an outer peripheral edge of the same general contour as the imperforate outer boundary of the perforated area and larger in area than the perforated areaO Means is also pro-vided for ~upporting the secondary panel in spaced overlapping relationship with the perforated area in a position normal to the path of air flow through the perforated area thereby defining a flow path to permit air flow through the perforated area and about the outer peripheral edge of the secondary panel while in-tercepting sound waves directed toward the secondary panel to attenuate engine noise originating inside the enclosure.
Figure 1 i9 a perspective view of a crawler tractor employing a noise attenuating engine enclosure in accordance with the invention:
Figure 2 is a top plan view of the tractor shown in Figure 1, Figure 3 is an enlarged side elevational view of the exterior side of the primary panel shown in Figures 1 and 2, Figure 4 is an elevational view taken on line 4-4 of Figure 3 and depicts diagrammatically the air flow path and the sound wave path at the edges of the secondary panel D
~073006 Figure 5 is an elevational view taken on line 5-5 of Figure 3, Figure 6 is a view similar to Figure 5 but showing a second type of secondary panel, and Figure 7 is a view similar to Figure 5 but showing a third type of secondary panel.
Referring to Figures 1 and 2, the numeral 10 desig-nates a crawler tractor having a chassis 12 on which an internal combustion engine 14 is mounted for driving the crawler tracks 16 and other power operated equipment mounted on the tractor in a conventional manner. The engine 14 is disposed within an engine enclosure 20 which generally comprises or is defined by a top wall 22, a rear end wall 24, a pair of side walls 26 and 28 on opposite lateral sides of the tractor 10 and a perforated radiator 30 at the front end of the _ 4a -C
107300~;
tractor. The engine is provided with a cooling fan 32 which draws air into the enclosure 20 through openings in the side walls 26 and 28 and expells the air through perforations in the radiator 30.
Figures 3, 4 and 5 show in detail the construction of the left side wall 28 of the enclosure 20. It is to be understood that the right side wall 26 of the enclosure 20 is similar to the left side wall 28 and, therefore, only the latter will be described in detail hereinafter. As Figure 3 shows, the side wall 28 comprises a first sheet metal section 34 which is rigidly secured to a suitable framework (not shown) which is understood to be rigidly mounted on the tractor chassis 12 and a second portion or wall panel 40 which is pivotably secured at its forward edge 12 to the first section 34 by an elongated hinge means 42. This arrangement enables panel 40 to be swung outwardly from a closed position (shown in the drawings) to an open position to afford access to the inside of the engine compartment. Suitable latch means 44 are pro-vided at the rear edge of panel 40 to lock the panel in closed position.
The wall panel 40 comprises a generally vertical upper section 46 and an integrally formed outwardly and down-wardly extending sloped lower section 48 to adapt the panel to the contour of the enclosure 20. The upper section 46 of panel 40 is provided with a plurality of holes or perforations 50 arranged in rows to provide a perforated area designated 52. The lower section 48 of panel 40 is provided with two such perforated areas 54 and 56, each containing a plurality of holes or perforations 50. The perforated areas 52, 54 and 56 permit cooling air to be drawn into or expelled from the inside of engine enclosure 20. Although circular holes 50 are shown, holes or perforations having other shapes could 1073(~06 be employed.
Since the perforated areas 54 and 56, if combined, would result in a relative long perforated area which would tend to weaken lower section 48 of panel 40, it is preferred to leave an unperforated strengthening region 51 therebetween.
In practice, it is preferred that panel 40 be fab-ricated with large cutout areas corresponding in shape to the perforated areas designated 52, 54 and 56 and to weld per-forated sheet metal on the inside of panel 40 so as to overlie the large cutout areas and thereby provide corresponding perforated areas. In Figure 3 the lines designated by the numberal 60 indicate the edges of the large cutouts on panel 40 and also correspond to the outer boundaries or edges of the perforated areas 52, 54 and 56. Figure 4 shows a perfor-ated member 53 which corresponds to or defines the perforated area 52 shown in Figure 3.
Panel 40 is hereinafter referred to in some instances as primary panel 40 to distinguish it from the two secondary panels 62 and 66 associated with the perforated areas 52 and 54, 56, respectively, associated therewith.
Referring to Figures 3, 4 and 5, each secondary panel 62 and 66 conforms in its general contour or outline to the shape of the perforated area 52 and 54, 56, respectively, with which it is associated. However, each secondary panel is larger in area than its associated perforated area or areas so that the edges of the secondary panel project beyond the edges 60 of the perforated area when the secondary panel is associated with the primary panel, as Figure 3 best shows.
The secondary panel 62 is supported in a fixed position with respect to and in spaced apart relationship from the inner side of primary panel 40 in reqistry with perforated area 52, as Figures 3 and 4 show. The secondary panel 66 is supported in a fixed position with respect to and in spaced apart relationship from the inner side of primary panel 40 in registry with perforated areas 54 and 56, as Figures 3 and 5 show.
Means are provided to rigidly support each secondary panel in the proper position with respect to its associated perforated area or areas. As Figures 3, 4 and 5 show, such means comprises brackets 70 welded to the inner side of panel 40 near a corner or an end of a secondary panel. The fasten-ing means further comprises bolts 72, each of which extendsthrough a hole 74 in an associated secondary panel and through a hole 76 in an associated bracket 70. A nut 75 screws onto the end of each bolt 72 to rigidly secure the secondary panel to an associated bracket 70. Secondary panel 62 employs three generally U-shaped support brackets 70, whereas secondary panel 66 employs two separate brackets 70, one of which is U-shaped and the other of which is generally L-shaped. In an actual embodiment of the present invention the perforated area 52 was on the order of 28 inches long, 20.4 inches high at the rear edge, 13.2 inches high at the forward edge. The distance between the inside surface of the primary panel and the outwardly facing surface of the secondary panel was on the order of 2-1/2 inches. The secondary panel was fabricated of 16-gauge sheet metal. Each edge of the secondary panel extended beyond the edge of its associated perforated area for a distance of at least approximately ]/2 inch.
Referring to Figures 4 and 5, it is apparent that each perforated area of a primary panel and its associated secondary panel are flat.
In the embodiment shown in Figure 5 the secondary panel 66 is fabricated of a solid, rigid non-acoustical mater-ial such as sheet steel having upturned outer edges. In the 1~373006 embodiment shown in Figure 6 the secondary panel 66A comprises a so:Lid, rigid sheet of non-acoustical material, such as panel 66, to the inner side of which (i.e., that side which faces engine 14) is bonded an acoustical material such as fiberglass insulating material, such as panel 66B. In the embodiment shown in Figure 7 the secondary panel 66B is fabri-cated of a rigid acoustical material such as polyurethane foam.
Referring to Figure 4, the arrows A depict the path of air flow from outside the engine compartment 20 to the inside therof when the engine 14 is operating to drive the radiator fan 32 to expel air outwardly through radiator 30.
As Figure 4 shows, the incoming air flow must follow a non-linear path in order to pass through any of the holes 50 in the perforated area and around any edge of the secondary panel 62. Figure 4 also schematically depicts the path which would be followed by sound waves designated 76 emanating from a poin1: on the surface of the engine 14. The sound waves 76 emanate outwardly from a central point, but any point in the wave 76 must necessarily follow a straight path. Therefore, because of the location and arrangement of the secondary panels 62 and 66 with respect to the engine 14 and the per-forated areas 52, 54 and 56 in the primary panel 40, sound waves emanating from the engine 14 cannot proceed directly from the engine to the holes 50 in the perforated area.
Therefore, although engine noise is thus attenuated, there is no substantial interference with necessary air flow between the outside of the engine compartment 20 and the exterior thereof.
Although the present invention is shown as being applied to an engine compartment for a tractor 10, it is apparent that it could be employed with other apparatus, -including stationary apparatus, employing an engine and requir-ing and engine enclosure. Furthermore, although three dif-ferent types of secondary panels are disclosed, it is apparent that secondary panels made of materials other than those spec-ified could be employed in accordance with the invention. In addition, although panel 40 is shown as comprising three dis-crete perforated areas 52, 54 and 56, it is apparent that a lessor greater number of perforated areas could be employed in a panel in accordance with the present invention. It is also apparent that mounting means of a type other than that disclosed could be employed. It is also apparent that, although circular holes 50 are shown, holes of other shapes could be employed, such as holes formed in a grid or screen formed of interwoven stiff wire or holes taking the form of linear type louvers punched in sheet metal. Similarly, hinge means and latch means other than those disclosed for panel 40 could be employed. The term "acoustical material", as employed herein, is intended to refer to any material which has the characteristic of deadening or damping sound, such as fiberglass batts, plastic foam, woven or felted materials, or the like, which are suitable for use in a relatively high temperature environment. Also, as Figures 1 and 3 show, stationary section 34 of side wall 28 comprises perforated areas 55 which are similar to area 52 and which have second-ary panels 57 similar to secondary panel 66 associated therewith.
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Claims (15)
1. In an engine enclosure, a primary panel having a perforated area defined by an imperforate outer boundary to permit air flow between the inside and outside of said enclosure, an imperforate secondary panel disposed inside said enclosure and having an outer peripheral edge of the same general contour as said imperforate outer boundary of said perforated area and larger in area than said perforated area, and means for supporting said secondary panel in spaced overlapping relationship with said perforated area in a posi-tion normal to the path of air flow through said perforated area thereby defining a flow path to permit air flow through said perforated area and about said outer peripheral edge of said secondary panel while intercepting sound waves directed toward said secondary panel to attenuate engine noise originating in-side said enclosure.
2. An enclosure according to claim 1 wherein said secondary panel is fabricated of non-acoustical material.
3. An enclosure according to claim 1 wherein said secondary panel is fabricated of acoustical material.
4. An enclosure according to claim 1 wherein said secondary panel includes acoustical material on that surface of said secondary panel which faces inwardly within the enclo-sure.
5. In an engine enclosure a pair of primary panels defining opposite sides of an engine enclosure, each one of said primary panels having a perforated area defined by an outer imperforate boundary to permit air flow between the inside and the outside of the enclosure through the perforations formed therein, and a pair of imperforate secondary panels disposed in-side the enclosure with each one of said secondary panels being spaced in overlapping parallel relationship to one of said primary panels, each one of said secondary panels being formed such that the outer peripheral edge thereof is of the same general contour as the outer peripheral edge of said adjacent primary panel and of an area larger than said perforated area allowing air flow between the inside and outside of the enclosure to circulate about said outer peripheral edge of each one of said secondary panels to be directed through the engine enclosure attenuating engine noise originating within the enclosure by intercepting sound waves radiated therefrom.
6. An enclosure according to claim 5 wherein at least one of said secondary panels is fabricated of non-acoustical material.
7. An enclosure according to claim 5 wherein at least one of said secondary panels is fabricated of acoustical material.
8. An enclosure according to claim 5 wherein at least one of said secondary panels includes acoustical material on that surface of said secondary panel which faces inwardly within the enclosure.
9. An engine enclosure comprising a side wall having an opening affording access to the inside of said enclosure, a wall panel pivotally connected to said side wall and movable between a closed position and an open position, said wall panel having at least one perforated area defined by an outer imperforate boundary for permitting air flow between the inside and outside of said enclosure when said panel is in said closed position, an imperforate secondary panel of the same general contour as said perforated area and larger in area than said perforated area, and means for securing said secondary panel to the in-side of said wall panel in spaced parallel overlapping rela-tionship with said perforated area with said secondary panel extending beyond said outer boundary of said perforated area in a position normal to the path of air flow through said per-forated area to allow air flow about the contour of the imper-forate secondary panel and through the enclosure while atten-uating engine noise originating inside said enclosure by pre-venting sound waves from passing through said imperforate secondary wall panel.
10. An enclosure according to claim 9 wherein said secondary panel is fabricated of non-acoustical material.
11. An enclosure according to claim 9 wherein said secondary panel is fabricated of acoustical material.
12. An enclosure according to claim 9 wherein said secondary panel includes acoustical material on that surface of said secondary panel which faces the inside of said enclo-sure.
13. An engine enclosure according to claim 9 wherein said wall panel comprises a plurality of said perforated areas and a plurality of said secondary panels, each said secondary panel being associated with at least one of said perforated areas.
14. In a vehicle having an engine, a fan driven by said engine for effecting air flow, and an engine enclosure for housing said engine and fan, wherein the enclosure is at least partly defined by a radiator, an end wall, a top wall and opposed side walls, the improvement comprising at least one of said opposed side walls having a perforated area defined by an outer imperforate boundary to permit air flow between the inside and outside of said enclosure, an imperforate secondary panel of the same general contour as said perforated area and larger in area than said perforated area, and, means for supporting said secondary panel in parallel overlapping relationship with the inner side of said perforated area with said secondary panel extending beyond said outer boundary of said perforated area and in a position normal to the path of air flow through said perforated area to permit air flow through said perforated area and about the general contour of the imperforate secondary panel while attenuating engine noise originating inside said enclosure by intercepting sound waves radiated therefrom.
15. A vehicle according to claim 14 wherein said secondary panel is connected to said side wall and said side wall further includes an access opening therethrough and means for movably supporting a primary panel portion of said side wall, comprising said perforated area defined by an outer imperforate boundary between positions wherein said access opening is open or closed.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US53794275A | 1975-01-02 | 1975-01-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1073006A true CA1073006A (en) | 1980-03-04 |
Family
ID=24144763
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA240,656A Expired CA1073006A (en) | 1975-01-02 | 1975-11-27 | Noise attenuating engine enclosure |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5189948A (en) |
| AU (1) | AU507834B2 (en) |
| BR (1) | BR7508709A (en) |
| CA (1) | CA1073006A (en) |
| DE (1) | DE2556606A1 (en) |
| FR (1) | FR2296560A1 (en) |
| GB (1) | GB1510229A (en) |
| IT (1) | IT1051835B (en) |
| SE (1) | SE7600015L (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4037682A (en) * | 1976-02-20 | 1977-07-26 | Fiat-Allis Construction Machinery, Inc. | Engine compartment enclosure |
| JP2019147527A (en) * | 2018-02-28 | 2019-09-05 | トヨタ自動車株式会社 | Vehicle front part structure |
-
1975
- 1975-11-27 CA CA240,656A patent/CA1073006A/en not_active Expired
- 1975-12-04 FR FR7537080A patent/FR2296560A1/en active Granted
- 1975-12-04 IT IT2998975A patent/IT1051835B/en active
- 1975-12-16 DE DE19752556606 patent/DE2556606A1/en not_active Ceased
- 1975-12-19 GB GB5209375A patent/GB1510229A/en not_active Expired
- 1975-12-24 JP JP50154674A patent/JPS5189948A/ja active Pending
- 1975-12-30 BR BR7508709A patent/BR7508709A/en unknown
-
1976
- 1976-01-02 SE SE7600015A patent/SE7600015L/en not_active Application Discontinuation
- 1976-01-05 AU AU10027/76A patent/AU507834B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| AU507834B2 (en) | 1980-02-28 |
| JPS5189948A (en) | 1976-08-06 |
| DE2556606A1 (en) | 1976-07-08 |
| SE7600015L (en) | 1976-07-05 |
| IT1051835B (en) | 1981-05-20 |
| BR7508709A (en) | 1977-08-02 |
| AU1002776A (en) | 1977-07-14 |
| GB1510229A (en) | 1978-05-10 |
| FR2296560A1 (en) | 1976-07-30 |
| FR2296560B1 (en) | 1980-08-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |