Noise attenuation in a Venturi device and/or check valves

Venturi devices for producing vacuum are disclosed that include a housing defining a motive port, a suction port, a discharge port, a first flow passage between the motive port and the discharge port, and a second flow passage into and through the suction port and into fluid communication with the first flow passage, a first check valve incorporated into the housing and positioned to control fluid flow through the suction port, and a sound attenuating wrap about the outer surface of the housing. The Venturi devices may also include a sound attenuating member disposed in the first flow passage downstream of the intersection of the second flow passage and the first flow passage, in the portion of the second flow passage leading into the suction port, in the first check valve, or combinations thereof.

TECHNICAL FIELD

This application relates to noise attenuation in Venturi devices for producing vacuum using the Venturi effect and/or check valves, and more particularly to noise attenuating wraps for use in conjunction therewith.

BACKGROUND

Engines, for example vehicle engines, have included aspirators or ejectors for producing vacuum, and/or check valves. Typically, the aspirators are used to generate a vacuum that is lower than engine manifold vacuum by inducing some of the engine air to travel through a venturi. The aspirators may include check valves therein or the system may include separate check valves. When the check valves are separate, they are typically included downstream between the source of vacuum and the device using the vacuum.

During most operating conditions of an aspirator or check valve, the flow is classified as turbulent. This means that, in addition to the bulk motion of the air, there are eddies superimposed. These eddies are well known in the field of fluid mechanics. Depending on the operating conditions, the number, physical size and location of these eddies are continuously varying. One result of these eddies being present on a transient basis is that they generate pressure waves in the fluid. These pressure waves are generated over a range of frequencies and magnitudes. When these pressure waves travel through the connecting holes to the devices using this vacuum, different natural frequencies can become excited. These natural frequencies are oscillations of either the air or the surrounding structure. If these natural frequencies are in the audible range and of sufficient magnitude, then the turbulence generated noise may be heard, under the hood and/or in the passenger compartment. Such noise is undesirable and new aspirators, ejectors, and/or check valves are needed to eliminate or reduce this type of noise.

SUMMARY

In one aspect, Venturi devices for producing vacuum are disclosed that overcome the problems with turbulence generated noise identified above. The Venturi devices include a housing defining a motive port, a suction port, a discharge port, a first flow passage between the motive port and the discharge port, and a second flow passage into and through the suction port and into fluid communication with the first flow passage, a first check valve incorporated into the housing and positioned to control fluid flow through the suction port, and a sound attenuating material about the outer surface of the housing. The Venturi devices may also include a sound attenuating member disposed in the first flow passage downstream of the intersection of the second flow passage and the first flow passage, in the portion of the second flow passage leading into the suction port, in the first check valve, or combinations thereof.

The sound attenuating material about the outer surface of the housing includes a first member conformed to the contours of the exterior surface of the housing and a second member surrounding the first member; thus, rendering the first member interposed between the housing and the second member. In one embodiment, the first member is a foamable material. In a second embodiment, the first member is molded to the contours of the exterior surface of the housing, and defines a more uniform outer surface once molded thereto. In one embodiment, the first member and the second member comprise different materials.

In another embodiment, the sound attenuating material about the outer surface of the housing is molded to the contours of the exterior surface of the housing, and defines a more uniform outer surface once molded thereto. In another embodiment, the sound attenuating material about the outer surface of the housing comprises a plurality of molded portions each having an inner surface contoured to match the contours of a portion of the exterior surface of the housing. The plurality of molded portions are seated against the exterior surface of the housing and are connected together and/or to the housing by a retention mechanism. In both of these embodiments, the sound attenuating wrap about the more uniform outer surface defined by the molded material or molded portions is optional.

The sound attenuating member(s) positioned inside the Venturi devices may be a plug of sound attenuating material. This plug of sound attenuating material may be disposed within the first flow passage, the second flow passage, or both thereof. In one embodiment, the sound attenuating member is porous such that fluid flow through the first flow passage, the second flow passage, and the check valve is not restricted. The sound attenuating member may comprise metals, plastics, ceramics, or glass. In one embodiment, the sound attenuating member comprises wire, woven or matted, sintered particles, woven or matted fibers, and combinations thereof.

In another aspect, check valves are disclosed that overcome the problems with turbulence generated noise identified above. Such check valves include a housing defining an internal cavity having a first port and a second port both in fluid communication therewith, a sealing member that is translatable between an open position and a closed position within the cavity, a sound attenuating member disposed within the cavity, within the first port, the second port, or both ports, and combinations thereof, and a sound attenuating material about the outer surface of the housing.

The sound attenuating material about the outer surface of the housing includes a first member conformed to the contours of the exterior surface of the housing and a second member surrounding the first member; thus, rendering the first member interposed between the housing and the second member. In one embodiment, the first member is a foamable material. In a second embodiment, the first member is molded to the contours of the exterior surface of the housing, and defines a more uniform outer surface once molded thereto. In one embodiment, the first member and the second member comprise different materials.

In another embodiment, the sound attenuating material about the outer surface of the housing is molded to the contours of the exterior surface of the housing, and defines a more uniform outer surface once molded thereto. In another embodiment, the sound attenuating material about the outer surface of the housing comprises a plurality of molded portions each having an inner surface contoured to match the contours of a portion of the exterior surface of the housing. The plurality of molded portions are seated against the exterior surface of the housing and are connected together and/or to the housing by a retention mechanism. In both of these embodiments, the sound attenuating wrap about the more uniform outer surface defined by the molded material or molded portions is optional.

The sound attenuating member(s) positioned inside the check valves may be a plug of sound attenuating material. This plug of sound attenuating material may be disposed within the first flow passage, the second flow passage, or both thereof. In one embodiment, the sound attenuating member is porous such that fluid flow through the first flow passage, the second flow passage, and the check valve is not restricted. The sound attenuating member may comprise metals, plastics, ceramics, or glass. In one embodiment, the sound attenuating member comprises wire, woven or matted, sintered particles, woven or matted fibers, and combinations thereof.

DETAILED DESCRIPTION

The following detailed description will illustrate the general principles of the invention, examples of which are additionally illustrated in the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.

FIG. 1is an external view of an aspirator-check valve assembly, generally identified by reference number100, for use in an engine, for example, in a vehicle's engine. The engine may be an internal combustion engine that includes a device requiring a vacuum. Check valves are normally employed in vehicle systems in the air flow lines between the intake manifold, downstream of the throttle, and the devices requiring vacuum. The engine and all its components and/or subsystems are not shown in the figures, with the exception of a few boxes included to represent specific components of the engine as identified herein, and it is understood that the engine components and/or subsystems may include any commonly found in vehicle engines. While the embodiments in the figures are referred to as aspirators because the motive port108is connected to atmospheric, the embodiments are not limited thereto. In other embodiments, the motive port108may be connected to boosted pressure such as the pressures attributed to boosted air produced by a turbocharger and, as such, the “aspirator” is now preferably referred to as an ejector.

The aspirator-check valve assemblies disclosed herein may have alternate embodiments such as the embodiment ofFIGS. 1 and 2and the embodiment ofFIG. 3, which are identified by reference numbers100,100′, respectively. Both aspirator-check valve assemblies100,100′ are connectable to a device requiring a vacuum102and create vacuum for said device102by the flow of air through a passageway144, extending generally the length of a portion of the aspirator-check valve assembly, designed to create the Venturi effect. The aspirator-check valve assemblies100,100′ include housing101, which as illustrated is formed of an upper housing portion104and a lower housing portion106. The designations of upper and lower portions are relative to the drawings as oriented on the page, for descriptive purposes, and are not limited to the illustrated orientation when utilized in an engine system. Preferably, upper housing portion104is joined to lower housing portion106by sonic welding, heating, or other conventional methods for forming an airtight seal therebetween.

Still referring toFIGS. 1-3, the lower housing portion106defines passageway144which includes a plurality of ports, some of which are connectable to components or subsystems of the engine. The ports include: (1) a motive port108, which may receive clean air from the engine intake air cleaner170, typically obtained upstream of the throttle of the engine; (2) a suction port110, which can connect via the check valve111to a device requiring vacuum102; (3) a discharge port112, which may be connected to an engine intake manifold172downstream of the throttle of the engine; and, optionally, (4) a bypass port114. Check valve111is preferably arranged to prevent fluid from flowing from the suction port110to the application device102when a sealing member136housed therein is translated to a closed position. In one embodiment, the device requiring vacuum102is a vehicle brake boost device. The bypass port114may be connected to the device requiring vacuum102and, optionally, may include a check valve120in the fluid flow path therebetween. Check valve120is preferably arranged to prevent fluid from flowing from the bypass port114to the application device102when a sealing member137housed therein is translated to a closed position.

As shown inFIGS. 2 and 3, lower housing portions106in both embodiments include lower valve seats124,126. Each lower valve seat124,126is defined by a continuous outer wall128,129, and, optionally, a bottom wall such as wall130in lower valve seat124. A bore132,133is defined in each lower valve seat124,126to allow for air flow communication with air passageway144. InFIG. 2, each lower valve seat124,126includes a plurality of radially spaced fingers134,135extending upwardly from an upper surface thereof. The radially spaced fingers134,135serve to support a sealing member136,137. InFIG. 3, only one of the lower valve seats, specifically lower valve seat124, includes a plurality of radially spaced fingers134. The second lower valve seat126includes a first sound attenuating member192rather than the plurality of radially spaced fingers. In another embodiment, not shown, both of the lower valve seats124,126may include sound attenuating members rather than the plurality of radially spaced fingers.

Referring again toFIGS. 1-3, the upper housing portion104is configured for mating to or with the lower housing portion106to form the check valves111,120, if both are present. Upper housing portion104defines passageway146extending the length thereof and defines a plurality of ports, some of which are connectable to components or subsystems of the engine. The ports include: (1) a first port148that may be capped with cap174or may be connected to a component or subsystem of the engine; (2) a second port150(part of the inlet port for chamber/cavity166) in fluid communication with the suction port110in the lower housing portion106, and between which the sealing member136is disposed; (3) a third port152(part of the inlet port for chamber/cavity167) in fluid communication with the bypass port114in the lower housing portion106, and between which the seal member137is disposed; and (4) a fourth port154which may function as an inlet connecting the aspirator-check valve assembly to a device requiring vacuum102.

As shown inFIGS. 2 and 3, the upper housing portion104in both embodiments includes upper valve seats125,127. Each upper valve seat125,127is defined by continuous outer wall160,161and bottom wall162,163. Both upper valve seats125,127may include a pin164,165extending downwardly from the bottom walls162,163, respectively, toward the lower housing portion106. The pins164,165function as a guide for translation of the sealing members136,137within the cavities166,167defined by the mated upper valve seat125with the lower valve seat124and defined by the mated upper valve seat127with the lower valve seat126. Accordingly, each sealing member136,137includes a bore therethrough sized and positioned therein for receipt of the pin164,165within its respective cavity166,167.

Referring again toFIGS. 2 and 3, the passageway144in the lower housing portion106has an inner dimension along a central longitudinal axis B (labeled inFIG. 3) that includes a first tapering portion182(also referred to herein as the motive cone) in the motive section180of the lower housing portion106coupled to a second tapering portion183(also referred to herein as the discharge cone) in the discharge section181of the lower housing portion106. Here, the first tapering portion182and the second tapering portion183are aligned end to end (outlet end184of the motive section180to inlet end186of the discharge section181). The inlet ends188,186and the outlet ends184,189may be any circular shape, ellipse shape, or some other polygonal or curved form and the gradually, continuously tapering inner dimension extending therefrom may define, but is not limited to, a hyperboloid or a cone. Some example configurations for the outlet end184of the motive section180and inlet end186of the discharge section181are presented inFIGS. 4-6of co-pending U.S. patent application Ser. No. 14/294,727, filed Jun. 3, 2014, incorporated by reference herein in its entirety.

As seen inFIGS. 2 and 3, the first tapering portion182terminates at a fluid junction with suction port110, which is in fluid communication therewith, and at this junction the second tapering portion183begins and extends away from the first tapering portion182. The second tapering portion183is also in fluid communication with the suction port110. The second tapering portion183then forms a junction with the bypass port114proximate the outlet end189of the second tapering portion and is in fluid communication therewith. The first and second tapering portions182,183typically share the central longitudinal axis B of the lower housing portion106.

Still referring toFIGS. 2 and 3, the second tapering portion183tapers gradually, continuously from a smaller dimensioned inlet end186to a larger dimensioned outlet end189. This inner dimension may be any circular shape, ellipse shape, or some other polygonal or curved form, including but not limited to a hyperboloid or a cone. The optional bypass port114intersects the discharge section190as described above to be in fluid communication with the second tapering section183. The bypass port114may intersect the second tapering section183adjacent to, but downstream of the outlet end189. The lower housing portion106may thereafter, i.e., downstream of this intersection of the bypass port, continue with a cylindrically uniform inner diameter until it terminates at the discharge port112. Each of the respective ports108,110,112, and114may include a connector feature on the outer surface thereof for connecting the passageway144to hoses or other features in the engine.

When either of the aspirator-check valve assemblies100,100′ is connected into an engine system, for example as illustrated inFIGS. 2 and 3, the check valves111and120function as follows. As the engine operates, the intake manifold172draws air into the motive port180, through passageway144and out the discharge port112. This creates a partial vacuum in the check valves111,120and passageway146to draw sealing members136,137downward against the plurality of fingers134,135(FIG. 2) or against the plurality of fingers134and the first sound attenuating member192(FIG. 3). Due to the spacing of fingers134,135and/or the porous nature of the first sound attenuating member192, free fluid flow from passageway144to passageway146is allowed. The partial vacuum created by the operation of the engine serves in the vacuum assistance of at least the operation of the device requiring vacuum102.

The air flow system in the typical internal combustion engine operates on the principle that as the engine operates, a partial vacuum is created in order to regulate the power produced by the engine. This vacuum has been found to be useful in supplementing vacuum assist subsystems in the vehicle, particularly brakes, fuel vapor purging systems, automatic transmissions and, most recently, air conditioners. Aspirator-check valve assemblies such as assemblies100,100′ may provide a connection between the main airway and the subsystem and serve to inhibit back pressure from the subsystem from disturbing airflow through the main airway.

With reference toFIG. 2, the solid arrows147represent the fluid flow within the aspirator-check valve assembly and the dashed arrows149represent the path for travel of the turbulence generated noise. The fluid flow within the aspirator-check valve assemblies described above is generally classified as turbulent. This means that in addition to the bulk motion of the fluid flow along arrows147, such as air, there are pressure waves traveling through the assembly and different natural frequencies can become excited, thereby resulting in turbulence generated noise along dashed arrows149. The aspirator-check valve assemblies100,100′ as seen inFIGS. 2 and 3include one or more sound attenuating members,192,194,196,198. The sound attenuating members192,194,196,198are placed within the flow path proximate, but downstream of the regions where turbulence generated noise is created.

The sound attenuating members192,194,196,198are porous such that fluid flow through and between the passageways144,146is not restricted, but sound (turbulence generated noise) is attenuated. As depicted inFIG. 2, there are two potential paths for the turbulence generated noise: (1) toward the engine intake manifold172; and (2) toward the device requiring vacuum102. To eliminate or reduce this noise, the porous elements are proximate but downstream of the source of the turbulent noise. For example, the sound attenuating members may be positioned in the discharge port, the suction port, proximate the bypass check valve120, and/or proximate the suction check valve111.

The check valves111,120can produce turbulent noise due to the flow therethrough. This noise would travel down either of the two connections as depicted by dashed arrows149(FIG. 2) along passageways144and146. Sound attenuating members194,196,198may be placed in either of the passageways144,146, and sound attenuating member192may be placed in check valve120. As seen inFIG. 2, the second sound attenuating member194is disposed proximate to or in the discharge port112because the discharge section190is one portion where such noise is created. Also inFIG. 2, the third sound attenuating member196is present and is disposed proximate to or in the fourth port154of passageway146because the flow path between the bypass port114, check valve120, and the fourth port154is one portion where such noise is created. As discussed above and illustrated inFIG. 3, the first sound attenuating member192is disposed within the cavity167of check valve120, specifically seated within the lower valve seat126.

The sound attenuating members192,194,196are porous as explained above and can be made from a variety of materials including metals, plastics, ceramics, or glass. The sound attenuating members may be made from wire, woven or matted, sintered particles, fibers woven or matted, but are not limited thereto. The porous character of the sound attenuating members causes the noise pressure waves to attenuate by interfering with themselves, but should be of sufficient size and shape to not unduly restrict fluid flow, for example, air flow. In one embodiment, the sound attenuating members192,194,196are not harmed (do not deteriorate) by operating temperatures of an engine based on placement of the aspirator in the engine system. Additionally, the sound attenuating members192,194,196are not harmed by vibrations experienced during operating conditions of the engine.

Referring now toFIGS. 4A-4C, stand-alone check valves202,203are shown that are independent of an aspirator assembly. The check valve202includes a housing204defining an internal cavity206having a pin264therein upon which is seated a sealing member236and defining a first port210in fluid communication with the internal cavity206and a second fluid port212in fluid communication with the internal cavity206. The internal cavity206typically has larger dimensions than the first port210and the second port210. In the illustrated embodiments, the first port210and the second port212are positioned opposite one another to define a generally linear flow path through the check valve202, when the sealing member136is not present, but is not limited to this configuration. The portion of the housing defining the internal cavity106includes an internal first seat214upon which the sealing member236seats when the check valve is closed and a second seat216upon which the sealing member236seats when the check valve is open. InFIG. 4B, the second seat216is a plurality of radially spaced fingers234extending into the internal cavity206from an interior surface of the internal cavity206that is more proximate the first port210. InFIG. 4C, the second seat216is a face or surface of a first sound attenuating member292.

As shown inFIGS. 4B and 4C, the check valves202,203each include at least one sound attenuating member. As discussed above, the first sound attenuating member292(FIG. 4C) may be positioned in the internal cavity206and provide the second seat216for the sealing member236. A second sound attenuating member294may be included as shown inFIG. 4Bproximate or in the opening defining the outlet to the first port210. A third sound attenuating member296may be included as shown inFIG. 4Bproximate or in the opening defining the inlet of the second port212. A check valve may include any one or more of these first, second, and third sound attenuating members292,294,296. The sound attenuating members are porous and may be or include any of the materials as discussed above.

The first sound attenuating member292may be a disc of porous material having a generally central bore therethrough or a partial bore therein to receive the pin264, but is not limited thereto. The second and third sound attenuating members294,296, may be generally cylindrical plugs of porous material, but are not limited thereto. The check valves202,203may also include any other sound attenuating features, materials, or members disclosed herein.

Referring now toFIGS. 5-6, a third embodiment of an aspirator-check valve assembly, generally designated100″, is disclosed. The aspirator-check valve assembly100″ functions in the same manner as described above with respect to the aspirator-check valve assemblies100,100′. The aspirator-check valve assembly100″ may include the housing101, the check valves111,120, and/or any of other components earlier described with respect to the aspirator-check valve assemblies100,100′. The aspirator-check valve assembly100″ may optionally include one or more of the sound attenuating members192,194,196.

The aspirator-check valve assembly100″ further includes a sound attenuating wrap300disposed about the outer surface of the housing101. The sound attenuating wrap300may enclose the entire longitudinal length of the aspirator-check valve assembly100,100′,100″ or only a portion thereof. The wrap300should not impede the use of the ports, such as the motive port108, discharge port112, and ports148,154. The sound attenuating wrap300may be secured about the housing101with tape, one or more retaining bands or sleeves, an adhesive, a system of ties, dovetail features, snap-fit members, or other suitable retention and/or mateable mechanism or combination thereof. If any one of bands, sleeves, or ties are used to secure the sound attenuating wrap300to the housing101, they may also include an attachment feature or member for securing the assembly to the vehicle or system. The sound attenuating wrap300has a thickness T, labeled inFIG. 6, which may vary depending upon the specific use of the assembly100″, the material used to construct the wrap300, the amount of the housing101encased by the wrap300, and the retention mechanism used to couple the wrap300to the housing101. In one embodiment, the thickness T may be about 1 mm to about 10 mm in thickness. In another embodiment, the thickness may be about 2 mm to about 5 mm.

Still referring toFIGS. 5 and 6, a sound-deadening material302may be interposed between the housing101and the sound attenuating wrap300, and establishes a generally uniform outer surface304thereof (compared to the relatively complex shape of the irregular outer surface of the housing101itself) that may further receive the sound attenuating wrap300. Compare, for example,FIG. 1, which shows the outer surface of housing101, withFIG. 5, which shows outer surface304of the sound-deadening material302, and withFIG. 8, which shows outer surface304′ of sound-deadening material302′. The sound-deadening material302may be disposed about all or a portion of the outer surface of the housing101associated with the longitudinal length thereof enclosed by the wrap300.

The sound attenuating wrap300and sound-deadening material302encapsulate the aspirator-check valve assembly100″, thereby preventing acoustic noise created inside the aspirator-check valve assembly100″ from being transmitted from the engine to the vehicle or other system in which the aspirator-check valve assembly100″ is disposed.

The wrap300can be made from a variety of insulation materials including metals, plastics, ceramics, glass, or a combination thereof, including any of the materials suitable for use for the sound attenuating members192,194,196. The sound-deadening material302may similarly be formed of any of these materials, including foamable material, including those that have insulating properties.

In another embodiment, the sound-deadening material may be molded to conform with the contours of the outer surface of the housing101, as shown inFIGS. 7 and 8, thereby forming a close-fitting sleeve of the sound-deadening material302′ about the housing101. The molded sound-deadening material302′ may be made from an acoustic dampening material that can withstand the operating conditions of the system it is incorporated into, such as a vehicle engine system and its temperature(s), vibration, exposure to oil, fuel, and or exhaust products, and moisture. Suitable materials include moldable foam and/or non-woven fabric available from Wm. T. Burnett & Co., Baltimore, Md. For example, but not limited to, moldable foams include polyether or polyester foams; non-woven fabrics include metal wools; felts include animal, mineral wool, or jute felt; and combinations thereof.

As illustrated inFIGS. 7 and 8, the molded sound-deadening material302′ may be present as multiple molded portions that mate together to define the close-fitting sleeve310. Here, the molded portions include a first molded portion302′aand a second molded portion302′bdivided along a vertical plane (relative to the orientation of the drawings as illustrated on the page) aligned with the central longitudinal axis B of the assembly100. In other embodiments, the molded portions may include three or more pieces that mate to define the close-fitting sleeve. The molded portions may be divided along a horizontal plane (relative to the orientation of the drawings as illustrated on the page), at a bisection between the two check valves, etc. Each of the molded portions302′a,302′bhas an inner surface306,307, respectively, that is contoured to match the contours of a portion of the exterior surface of the housing101. As shown inFIG. 8, the plurality of molded portions302′a,302′bare seated against the exterior surface of the housing and are connected together and/or to the housing by a retention mechanism.

The retention mechanism may include tape, one or more retaining bands or sleeves, an adhesive, a system of one or more ties, dovetail features, snap-fit members, or other suitable mateable mechanism, and combinations thereof. If any one of bands. sleeves, or ties are used to secure the sound-deadening material302′ to the housing101, they may also include an attachment feature or member for securing or be long enough to secure the assembly to the vehicle or system in which the device is incorporated.

In another embodiment, the sound-deadening material may be an overmolded sound-deadening material302″ as shown inFIG. 9. Here, the sound-deadening material302″ defines a close-fitting seamless sleeve312about the housing101. To form the seamless sleeve312, a completed Venturi device or check valve is placed in an injection molding machine (not shown) in a fixture positioning the Venturi device or check valve with a preselected clearance distance between the interior surfaces of a mold and the exterior surfaces of the Venturi device or check valve, thereby defining a gap in which the sound-deadening material is received. In one embodiment, the sound-deadening material is injected using an injection molding technique and/or injection molding device into the gap. The sound-deadening material may be any material that absorbs sound and withstands the environmental conditions the Venturi device or check valve will experience once connected to a system, but is also a material suitable for injection into the gap at a temperature below the softening and/or melting point of the material defining the Venturi device or check valve, For example, but not limited to, polyester foam.

In the embodiments ofFIGS. 7-9, the outer sound attenuating wrap300(FIGS. 5 and 6) is optional.