GB2551361A

GB2551361A - Apparatus and method for noise dampening

Info

Publication number: GB2551361A
Application number: GB1610404.4A
Authority: GB
Inventors: Redfern Luke
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2016-06-15
Filing date: 2016-06-15
Publication date: 2017-12-20
Anticipated expiration: 2036-06-15
Also published as: GB2551361B; GB201610404D0

Abstract

A noise dampening device 200, such as a Helmholtz resonator, for dampening noise from a vehicle component (e.g. turbocharger) comprises a cavity resonator 202 having an internal volume. A change of rotational speed of the device causes a change of one or both of a dimension of an opening (104, fig 1) to the resonator, and an internal volume of the cavity resonator. This changes a frequency of noise damped by the device. A change of rotational speed may cause at least one moveable member 206, 204 to change position, which changes the area of the opening or the volume of the cavity. The moveable member may be biased non-linearly proportional to load. The device may be mountable to a rotating shaft of the vehicle component and rotation of the device may be driven by rotation of the component.

Description

APPARATUS AND METHOD FOR NOISE DAMPENING

TECHNICAL FIELD

The present disclosure relates to a noise dampening device and particularly, but not exclusively, to a noise dampening device for a turbocharger. Aspects of the invention relate to a noise dampening device, a turbocharger, a vehicle or engine and a method.

BACKGROUND

Exhaust turbochargers for vehicle engines are well known. Turbochargers are known to produce a characteristic ‘whine’ which is a high pitched drone associated with the operation of the compressor. Typically a resonator is installed in an intake air delivery system to the turbocharger to dampen the whine of the turbocharger.

The resonators normally comprise a Helmholtz resonator, also known as a cavity resonator, which dampens the noise produced by the turbocharger. A Helmholtz resonator has a fixed resonant frequency around which the resonator attenuates or dampens sound. The resonant frequency of a Helmholtz resonator is determined by the volume of the cavity and the dimensions of the neck or opening to the cavity. The mass of air in the neck essentially oscillates with the air in the cavity acting as a spring supporting it. Because the resonator dampens around its resonant frequency, which is fixed, the Helmholtz resonator has a narrow band of sound attenuation.

Resonators, when applied to turbochargers or other vehicle components have the drawback that they only attenuate in a narrow spectrum of frequencies. Therefore, if the frequency of turbo ‘whine’ deviates from the resonant frequency of the resonator, the efficacy of noise attenuation by the resonator decreases.

Resonators, particularly those applied to turbochargers, are often bulky. In order to provide sound attenuation at the frequencies needed to suppress turbo ‘whine’, the resonator will often take up approximately three litres of volume in the air intake to the compressor.

It is an object of embodiments of the invention to at least mitigate one or more of the problems of the prior art.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a noise dampening device, a turbocharger, a vehicle or engine and a method as claimed in the appended claims.

According to an aspect of the invention there is provided a noise dampening device to dampen noise from a moving component comprising; a cavity resonator having an internal volume, at least one opening to the resonator, wherein the noise dampening device is configured so that a change of motion of the noise dampening device causes a change of frequency spectrum of noise dampening by the noise dampening device.

In an embodiment, the noise dampening device is configured so that a change of motion of the noise dampening device causes a change of one or both of a dimension of the at least one opening and the internal volume of the cavity resonator.

In an embodiment, the noise damping device is configured so that a change of motion of the noise dampening device causes the resonant frequency of the of the noise dampening device to change.

In an embodiment, the noise dampening device dampens noise from a vehicle component.

In an embodiment, the change of dimension of the at least one opening causes a change of frequency spectrum of noise dampening by the noise dampening device.

In an embodiment, the change of internal volume of the cavity resonator causes a change of frequency spectrum of noise dampening by the noise dampening device.

By providing a noise dampening device where the motion of the device causes the frequency spectrum of noise dampening to change, a noise dampening device with adaptable dampening may be achieved. This adaptable dampening may be achieved without the need for complex control systems.

In an embodiment, the change of motion of the noise dampening device may be a change in rotational speed about a single axis.

In an embodiment, the noise dampening device may be configured so that the change of motion of the noise dampening device causes the area of the at least one opening to change.

In an embodiment, the noise dampening device may be configured so that an increase of the rotational speed of the noise dampening device causes an increase of the frequency of peak noise dampening by the noise dampening device.

An increase of rate of operation of some moving components may cause an increase of the frequency of peak noise produced by the moving component. Configuring the noise dampening device to operate as described above may provide a noise dampening device with improved noise dampening when used with such a moving component.

In an embodiment, the noise dampening device may further comprise at least one moveable member, and wherein the noise dampening device is further configured so that the change of rotational speed of the noise dampening device causes the moveable member to change position, and wherein the change of the position of the moveable member causes a change of the area of the at least one opening and/or a change of the volume of the cavity resonator.

This may provide an arrangement with improved simplicity for changing the frequency spectrum of noise dampening by the dampening device.

In an embodiment, the at least one movable member may be configured to move in a direction orthogonal to an axis of rotation of the dampening device.

This may provide a simple arrangement for changing a dimension of the at least one opening. Configuring the moving member to move orthogonal to the axis of rotation permits it to move easily under the influence from a change in centrifugal force arising from rotation of the dampening device.

In an embodiment, the area of the at least one opening is shaped so that the change of area of the opening with displacement of the moveable member is non-linear. In an embodiment, the width of the opening may vary along a direction perpendicular the axis of rotation of the noise dampening device, so that a linear displacement of the at least one moving member can produce a non-linear change of area of the opening.

Using different shapes of the opening, the change of frequency of peak noise dampening can be tuned to match the change in noise from the vehicle component.

In an embodiment, the noise dampening device may comprise a biasing means to bias the at least one moveable member. The biasing means may comprise a spring configured to bias the at least one moveable member.

This may provide an arrangement with further reduced bulk or improved simplicity for controlling the dimension of the opening. The stiffness of the biasing means may be varied to produce the desired change of opening dimension in response to a change of rotational speed, providing further improvements of adaptability.

In an embodiment, the biasing means may displace non-linearly, proportional to load.

This may provide further improved noise dampening for moving components whose frequency of noise changes non-linearly with increased speed of motion of the moving component. The change of noise dampening can be tuned to changes in noise from the moving component by varying the stiffness of the biasing means. The biasing means may comprise, for example, a non-linear spring or non-linear air spring.

In an embodiment, the moving component may comprise a vehicle component.

In an embodiment, the moving component may comprise a vehicle engine.

In an embodiment, the moving component may comprise a turbocharger for a vehicle engine.

In an embodiment, the noise dampening device may be configured so that the motion of the noise dampening device may be driven by the motion of the moving component. In an embodiment, the noise dampening device may be configured so that the motion of the noise dampening device may be driven by the motion of a moving component so that an increase of the speed of motion of the moving component provides an increase of speed of motion of the noise dampening device. The noise dampening device may be configured by comprising a connection for driving motion, such a connection may comprise a mounting for a belt, a gear or any other connection means known to drive motion.

This provides a convenient arrangement for changing the motion of the noise dampening device, to match the change of noise from the moving component as its rate of motion changes.

In an embodiment, the noise dampening device is configured so that the motion of the noise dampening device is driven by rotation of a compressor of a turbocharger. The noise dampening device may be configured by comprising a connection for driving motion, such a connection may comprise a mounting for a belt, a gear or any other connection means known to drive motion.

This may further simplify the arrangement for adapting the noise dampening of a noise dampening device to match the change of pitch of ‘turbo whine’ from a turbocharger.

In an embodiment, the moving component may comprise a rotating shaft, and the noise dampening device may be mountable to the rotating shaft of the moving component. In an embodiment, the noise dampening device may comprise connection points to allow it to be mounted to a shaft, or the shaft may be adapted so that the noise dampening device may be mounted to it, for example.

This may provide a further reduction in bulk because the noise dampening device can be mounted onto the rotating shaft. For example, where the shaft comprises a shaft of a turbocharger, this may also provide a simple arrangement for adapting noise dampening of a noise dampening device to match the change of pitch of ‘turbo whine’ from a turbocharger.

In an embodiment, the noise dampening device may be integrated into the shaft of the moving component. Where the moving component comprises part of a turbocharger, the noise dampening device may be integrated into the compressor, or integrated into the intake or compressor impellors of a turbocharger. This may provide a further reduction of bulk of a turbocharger.

In a further aspect, a turbocharger comprises a dampening device of an aspect of the present invention.

In a further aspect, an engine or vehicle comprises the turbocharger or dampening device of an aspect of the present invention.

In a further aspect, there is provided a method of dampening noise from a moving component comprising rotating a noise dampening device of an aspect of the present invention; changing the speed of rotation of the noise dampening device; wherein, either: changing the speed of rotation of the noise dampening device causes a change of dimension of at least one opening to the cavity resonator of the noise dampening device; and wherein, the change of dimension of the at least one opening changes a frequency spectrum of noise dampening by the noise dampening device; or, changing the speed of rotation of the noise dampening device causes a change of volume of the cavity resonator of the noise dampening device; and wherein, the change of volume changes a frequency spectrum of noise dampening by the noise dampening device.

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.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Figure 1 shows a representation of an embodiment of the invention;

Figure 2 shows alternative representation of an embodiment of the invention; and,

Figure 3 shows a representation of an embodiment of the invention.

Figure 4 show a representation of an embodiment of the invention.

DETAILED DESCRIPTION

An embodiment of the noise dampening device of the present invention is represented in figures 1 and 2. The noise dampening device 100 comprises a resonator portion 102 bound by a housing to form a cavity, the noise dampening device also comprises an opening 104 in the housing. Together, the resonator 102 and opening 104 form a Helmholtz resonator. Whilst a single opening is depicted in figures 1 and 2, any number of openings may be used.

The noise dampening device depicted in figures 1 and 2 comprises a pair of moveable members 106 in the form of slideable masses. The moveable members 106 are configured to slide over the opening in the housing of the resonator. As the moveable members 106 move outwards, the area of the opening 104 increases. The members 106 are biased by biasing means (not shown) which may be in the form of a spring, an air spring or other resilient device. The biasing means can be arranged so that the moveable members are biased towards the axis of rotation 108 of the noise dampening device, to a position that minimises the size of the opening 104.

Rotation of the noise dampening device 100 applies a centrifugal force to the moveable members 106, urging them outwards, to act against the biasing means. Increasing the speed of rotation increases the centrifugal force acting on the moveable members pushing them further outwards against the biasing means. As the moveable members move further outward, the area of the opening 104 increases.

The resonant frequency of a Helmholtz resonator is proportional to the area of its opening, and inversely proportional to the volume of its cavity and length of its opening. Therefore, increasing the area of the opening increases the resonant frequency of the dampening device. Changing the speed of rotation of the noise dampening device will change the resonant frequency of the noise dampening device, and thus change the frequency of peak noise dampened by the noise damping device attenuates. The same effect can be achieved by configuring the noise dampening device so that a change of rotation causes the length of opening or volume of its cavity to change.

The frequency of peak noise produced by the vehicle component may be considered to be the fundamental frequency of the noise produced by the vehicle component.

Figure 3 is a representation of a turbocharger 300 comprising a compressor 302 and a turbine 304. The noise dampening device 100 is mounted on to the shaft 306 at the compressor side. In this position, the noise dampening device 100 rotates with the shaft 300. As the speed of rotation of the shaft increases, the ‘turbo whine’, which is predominantly produced by the compressor, increases in frequency. Thus, the frequency of peak noise dampening by the dampening device increases to match the change of frequency of the turbo ‘whine’, providing adaptive dampening to the turbocharger. The noise dampening device may be positioned to dampen noise from any moving vehicle component.

The noise dampening device can also be mounted onto, or integrated into a rotating component of a turbocharger such as the compressor impellor, turbine rotor or other engine component for example.

The noise dampening device may be connected through drive means to the vehicle component, so that as the vehicle component rotates, so too does the noise damping device. The drive means may be in the form of a belt or gear system, or the noise dampening device may be connect directly to the vehicle component or integrated into it for example. Drive may be also provided by other means such as a motor, or may involve clutches or other known mechanical devices.

The skilled person can select the biasing means, shape of the opening and/or shape of the moveable member, for example, to tune the change of resonant frequency to the change in frequency of vehicle component noise. Tuning may also be achieved by varying the change of speed of rotation of the noise dampening device to the change of speed of the vehicle component.

The biasing means may be linear or non-linear, i.e. the biasing means may displace linearly or non-linearly proportional to an applied load. An appropriate stiffness and linearity of the biasing means may be selected so that the change of resonant frequency with increased speed of motion of the noise dampening device matches the change of frequency of vehicle noise with increased speed of vehicle component rotation.

Whilst two moveable masses are depicted in figures 1 and 2, any number may be used. The moveable member need not be limited to a slideable mass. The moveable member may for example involve a rotatable member that is hingedly connected to the resonator so that rotation of the member changes a dimension of the opening.

The mass of the at least one moveable mass may be varied so that the desired movement occurs depending on the changing magnitude of centrifugal force. Mass of the at least one moveable mass may therefore be used for tuning the changing resonant frequency of the noise dampening device with the changing frequency of vehicle noise.

Alternatively, the dampening device may be configured so that the dimension of the at least one opening that changes is the length of the opening. This may be achieved, for example, by using a moveable member that is a biased tube that slides outward or inward with changing centrifugal force.

Alternatively, the damping device may be configured so that the volume of the cavity changes with speed of rotation. This may be achieved for example, by using a moveable member within the cavity, arranged against a biasing means to move with changing centrifugal force. Figure 4 is a representation of a damping device 200 comprising an internal cavity, wherein a change in rotation of the damping device may change the volume 202 of the internal cavity. The damping device may optionally comprise moveable members 206 actuated by rotation of the damping device.

The volume 202 of the cavity inside the damping device can be reduced, for example, as speed of rotation increases through the use of a centrifugal mechanism. A centrifugal mechanism may comprise one or more weights 204, connected to a piston 210, the piston may be configured to move to vary the size of the volume 202 in the internal cavity. The weights 204 may be connected to the piston 210 by an actuating mechanism, which may comprise one or more rods and pivots. In figure 4, the actuating mechanism comprises a central actuating rod 220 and two linkage rods 222, which mechanically link the weights to the piston. The linkage rods are connected to the central actuating rod by a floating pivot 224 and to the body of the damping device by further linkages with fixed pivots 226 and floating link pivots 228. As the damping device speed increases about the central axis 212, the two weights 204 are displaced outward as represented by the arrows 208. As the central actuating rod 220 is attached to both the base of the piston 210 and to one end of the linkage rods, as the weights 204 move outwards with increasing speed, the actuating rod 220 moves in the direction of arrow 205. This extends the spring 214 and the piston 210 moves to reduce the cavity volume 202.

Reducing speed has the opposite effect, and so increases the cavity volume 202. As speed reduces, the centrifugal force acting in the direction of arrow 208 reduces and the spring 214 pulls the weights 204 back towards the central axis 212 of the damping device 200 via the mechanism linkages. Alternative mechanisms for varying the volume will be apparent to the skilled person.

The noise dampening device need not be driven by rotation, any change in momentum or acceleration resulting from motion of the noise displacement device can be used to move at least one moveable member.

The noise dampening device may be used to dampen noise produced by any moving component, including any rotating component. Examples include: motors, for example those used in tools and electric vehicles; engines, for example those used in vehicles, electrical generators or other static applications; turbines; or any other rotating machinery.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments which fall within the scope of the claims.

Claims

1. A noise dampening device for dampening noise from a vehicle component, comprising: a cavity resonator having an internal volume, at least one opening to the cavity resonator, wherein the noise dampening device is configured so that a change of rotational speed of the noise dampening device causes a change of one or both of a dimension of the at least one opening to the cavity resonator and the internal volume of the cavity resonator, thereby changing a frequency spectrum of noise dampening by the noise dampening device.

2. A noise dampening device according to claim 1, wherein the noise dampening device is configured so that the change in rotational speed of the noise dampening device causes the area of the at least one opening to change.

3. A noise dampening device according to any of claims 1 or 2, wherein the noise dampening device is configured so that an increase of rotational speed of the noise dampening device causes an increase in the frequency of peak noise dampening by the noise dampening device.

4. A noise dampening device according to any of claims 1 to 3, wherein the dampening device comprises at least one moveable member, and wherein the noise dampening device is configured so that a change of rotational speed of the noise dampening device causes the at least one moveable member to change position, wherein the change of position of the moveable member causes the changing of the area of the at least one opening and/or volume of the resonator.

5. A noise dampening device according to claim 4 wherein the at least one movable member is configured to move in a direction orthogonal to an axis of rotation of the dampening device.

6. A noise dampening device according to any of claims 4 or 5, wherein the area of the at least one opening is shaped so that the change of area of the opening with displacement of the moveable member is non-linear.

7. A noise dampening device according to any of claims 4 to 6, comprising a biasing means to bias the at least one moveable member.

8. A noise dampening device according to claim 7, wherein the biasing means displaces non-linearly, proportional to load.

9. A noise dampening device according to any of claims 1 to 8, wherein noise damping device is configured so that the rotation of the noise dampening device is driven by rotation of the vehicle component.

10. A noise dampening device according to claim 9, wherein the vehicle component comprises a rotating shaft, and the noise dampening device is mountable to the rotating shaft.

11. A noise dampening device according to any previous claim, wherein the vehicle component is a turbocharger.

12. A turbocharger comprising a noise dampening device according to any previous claim.

13. A turbocharger according to claim 12 wherein the noise dampening device is configured to rotate about the same axis as a shaft of the turbocharger.

14. A turbocharger according to claim 12, wherein the noise dampening device is integral with the shaft, or integral with the intake or compressor impellors of the turbocharger.

15. An engine or vehicle comprising a noise dampening device according to any of claims 1 to 11 or a turbocharger according to any of claims 12 to 14.

16. A method of dampening noise from a vehicle component, comprising: rotating a noise dampening device of any of claims 1 to 12; and changing the speed of rotation of the noise dampening device; wherein, one or both of: changing the speed of rotation of the noise dampening device causes a change of dimension of at least one opening to the cavity resonator of the noise dampening device; and wherein the change of dimension of the at least one opening changes a frequency spectrum of noise dampening by the noise dampening device; and, or changing the speed of rotation of the noise dampening device causes a change of volume of the cavity resonator of the noise dampening device; and wherein the change of volume changes a frequency spectrum of noise dampening by the noise dampening device.

17. A noise dampening device or a method of dampening noise from a vehicle component substantially as described herein and optionally with respect to the accompanying drawings.