GB2612070A

GB2612070A - Pneumatic valve damping to improve air venting noise

Info

Publication number: GB2612070A
Application number: GB2115071.9A
Authority: GB
Inventors: Andrews Jake
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2021-10-21
Filing date: 2021-10-21
Publication date: 2023-04-26
Anticipated expiration: 2041-10-21
Also published as: GB2612070B; GB202115071D0

Abstract

Aspects of the present invention relate to an apparatus 100 for use in an air suspension exhaust system. The apparatus 100 comprises a valve 110 shaped at a first end to engage with a biasing member 130 and enclosing a first cavity 180 at least partially defined by the valve 110. The apparatus 100 further comprises a housing 120 configured to house the valve 110 and the biasing member 130. The housing 120 comprises an air inlet 140; an air outlet 160; and an exhaust channel 150 provided between the air inlet 140 and the air outlet 160. The valve 110 is movable between a closed position in which the valve 110 blocks passage of air through the exhaust channel 150 and an open position in which air can pass through the exhaust channel 150. The valve 110 comprises an aperture 115 provided through a wall of the valve 110 so as to allow air that flows through the exhaust channel 150 from the air inlet 140 to the air outlet 160 in dependence on a position of the valve 110 into the first cavity 180. An air suspension system including the apparatus 100, and a vehicle including such an air suspension system are also disclosed.

Description

Pneumatic valve damping to improve air venting noise

TECHNICAL FIELD

The present disclosure relates to pneumatic valve damping to improve air venting noise.

Aspects of the invention relate to an apparatus for use in an air exhaust system, to an air suspension exhaust system, and to a vehicle. In particular, the present invention relates to pneumatically damping a valve in an exhaust system of an air suspension system using exhaust air to reduce a speed at which the valve opens.

BACKGROUND

It is known to provide air suspension systems in vehicles for maintaining and controlling ride height, and to dampen movements of the vehicle, particularly to reduce user perception of uneven road surfaces and to improve user comfort. Vehicle air suspension systems are known to include one or more air springs, which when installed around a vehicle and filled with compressed air, serve to adjust a vehicle ride height and to mitigate unwanted movement of the vehicle cabin caused by travelling over uneven surfaces. The air springs may be filled with compressed air to varying pressures to change a vehicle ride height or to adjust the vehicle response to travel over an uneven surface.

The suspension systems typically comprise one or more air springs, a gallery for supplying compressed air to the air springs, a compressor for compressing air to supply to the gallery, and an exhaust for removing compressed air from the suspension system. The gallery may comprise a volume connecting the compressor to the one or more air springs and the exhaust via one or more valves which control the passage of compressed air. The gallery may also connect the exhaust and compressor to other components, such as a compressed air reservoir. The gallery may also be known as a compressed air gallery, a common gallery or a central gallery.

In certain situations, the suspension system, and in particular the gallery, may be required to decompress by removing compressed air from the suspension system or the gallery, such that the suspension system or the gallery contains air at approximately atmospheric pressure. This is usually achieved by opening the exhaust to vent compressed air from the system. As the gallery typically contains compressed air at pressures exceeding atmospheric pressure, opening the exhaust valve releases the compressed air to the external environment.

The exhaust enables high pressure compressed air from the gallery to exit the suspension system into the external environment via the exhaust, which may comprise a valve operable to open and close. In certain vehicles, due to a high pressure differential between the gallery and the external environment, which is typically at atmospheric pressure, the release of compressed air from the gallery via the exhaust can be noisy both internally and externally to the vehicle, and result in noticeable and unwanted discomfort for a user of the vehicle and nearby persons.

In some examples, the exhaust may include a valve connecting the air suspension system to the external environment. The valve may be configured to be opened pneumatically by using the compressed air in the air suspension system, for example by providing the compressed air to a particular location to apply force to the valve to open the valve, which may otherwise be held closed, for example by a spring. However, due to the potentially high air pressures in the air suspension system, opening the valve in this way may result in a rapid opening of the valve which causes excessive noise or movement of the vehicle perceptible to a user of the vehicle or nearby persons. In certain examples, noise associated with venting may be more problematic in larger vehicles or vehicles with rapid ride adjustment features. Approaches to reducing the noise associated with venting may include reducing operating system air pressures, but this may interfere with operation of a vehicle, for example by reducing available air pressure for ride height adjustment. Another approach may relate to adjusting a force holding the valve closed, for example reducing a spring force to reduce the force required to open the valve, but this may interfere with a pressure relief function of the exhaust valve, which may be required in an event of excess system pressure.

It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide an apparatus for use in an air suspension exhaust system, an apparatus for use in an air suspension exhaust system for use in an air suspension system of a vehicle, and a vehicle as claimed in the appended claims.

According to an aspect of the present invention there is provided an apparatus for use in an air suspension exhaust system, the apparatus comprising: a valve shaped at a first end to engage with an biasing member and enclosing a first cavity at least partially defined by the valve; and a housing configured to house the valve and the biasing member, the housing comprising: an air inlet; an air outlet; and an exhaust channel provided between the air inlet and the air outlet; wherein the valve is movable between a closed position in which the valve blocks passage of air through the exhaust channel and an open position in which air can pass through the exhaust channel; and wherein the valve comprises an aperture provided through a wall of the valve so as to allow air that flows through the exhaust channel from the air inlet to the air outlet in dependence on a position of the valve into the first cavity.

In an embodiment, the air suspension exhaust system is part of an air suspension system of a vehicle. Advantageously, the opening of the valve is pneumatically dampened by the passage of air through the aperture. That is, the speed of opening of the valve is reduced. Further, the maximum flow rate of air through the exhaust channel is not changed compared to a system omitting the aperture, and therefore after the smoother, slower opening of the valve, the apparatus still allows for rapid exhaust of air.

In an embodiment, the valve is hollow and the aperture is configured to provide a channel for air to move through a wall of the valve into the first cavity. Advantageously, exhaust air, being air that is passing through the exhaust channel from the air inlet to the air outlet, is able to enter the first cavity. The ingress of air into the first cavity increases an air pressure in the first cavity which acts against an air pressure in a second cavity, the air pressure in the second cavity acting to open the valve, thus slowing down a speed of opening of the valve and reducing an associated noise. Additionally, advantageously the apparatus makes use of existing exhaust air to pneumatically dampen the opening of the valve and thus does not require additional air inputs or controls to perform the dampening.

In an embodiment, the aperture is positioned to allow exhaust air which is passing through the exhaust channel when the valve is at least partially in the open position to enter the first cavity.

Advantageously, due to the positioning of the aperture, the opening of the valve is pneumatically dampened as the valve opens and air passes through the exhaust channel, thus ensuring a smooth opening of the valve.

In certain embodiments, the when the valve is in the open position, air is permitted to pass from the air inlet through the exhaust channel and the aperture into the first cavity, and when the valve is in the closed position, air is not permitted to pass from the air inlet through the exhaust channel and the aperture. Advantageously, the aperture is positioned to make use of existing exhaust air.

In an embodiment, the air inlet, the air outlet and the exhaust channel are defined by an internal structure of the housing; the air outlet is configured to allow air to exit the housing; the air inlet is configured to receive air from a vehicle system into the housing; the exhaust channel is configured to direct air from the air inlet to the air outlet in dependence on a position of the valve; and the biasing member is biased against the first end of the valve to bias the valve toward the closed position.

In certain embodiments, the exhaust channel comprises a first portion connected to the air inlet and a second portion connected to the air outlet; and the first portion and the second portion are selectively connected in dependence on the position of the valve. The valve is therefore configured to open and close the exhaust channel to respectively allow or prevent air from exiting the apparatus.

In certain embodiments, the aperture is provided through an area of the wall of the valve proximal to the air outlet to connect the second portion of the exhaust channel to the first cavity.

In certain embodiments, the apparatus comprises one or more further apertures configured to allow air flow between the second portion of the exhaust channel and the first cavity. Advantageously, by providing multiple apertures to allow air flow into the first cavity, an importance of an orientation of the valve with respect to the housing during installation is reduced, and assembly is simplified. An increase in the level of damping may also increase due to the provision of multiple apertures.

In certain embodiments, the apparatus comprises a pilot inlet configured to direct air into a second cavity, the second cavity surrounding at least a portion of the valve and at least partially defined by the portion of the valve and the housing, such that, when air enters the second cavity from the pilot inlet, an air pressure in the second cavity is increased to act against the force of the biasing member to move the valve toward the open position. The valve is thereby opened by the passage of air through the pilot inlet.

In certain embodiments, the apparatus comprises at least one second sealing element provided on a surface of the valve to seal at least one gap between the valve and the internal surface of the housing to enclose the second cavity to thereby contain air in the second cavity.

Advantageously, the second cavity is sealed to prevent unwanted escape of air from the second cavity, thereby enabling an air pressure to be increased within the second cavity to open the valve.

In certain embodiments, the apparatus is a slave valve configured to open and close in dependence on movement of air through the pilot inlet.

In certain embodiments, the aperture has a substantially circular cross-section.

In certain embodiments, the aperture has a diameter of between approximately 0.5mm and 2.5mm. In one embodiment, the aperture has a diameter of approximately 2mm.

In certain embodiments, the aperture defines a channel for air through the wall of the valve and wherein the aperture has a length of approximately 'I mm to 3mm.

In certain embodiments, the first cavity is configured to at least partially house the biasing member.

In certain embodiments the first cavity is enclosed by the valve and the housing.

In certain embodiments, the apparatus comprises at least one first sealing element provided on a surface of the valve to seal at least one gap between the valve and an internal surface of the housing to enclose the first cavity to thereby contain air in the first cavity. Advantageously, unwanted escape of air from the first cavity is prevented and an air pressure within the first cavity can be increased by the ingress of air to the first cavity to pneumatically dampen the opening of the valve.

In an embodiment, the first cavity is a volume sealed so as to prevent the passage of air into or out of the first cavity except for via the aperture.

In certain embodiments, the valve is substantially hollow; and the first cavity comprises a volume at least partially defined by the hollow.

In certain embodiments, the biasing member comprises a spring configured to bias the valve toward the closed position.

In certain embodiments, the air inlet comprises a connection for connecting the apparatus to an exhaust system containing air.

According to another aspect of the invention, there is provided an air suspension exhaust system for use in an air suspension system of a vehicle, the air suspension exhaust system comprising: the apparatus; and at least one volume configured to store air and configured to be connected to the air inlet.

In certain embodiments, the at least one volume comprises at least part of an air suspension system.

In certain embodiments, the air suspension system includes an air gallery containing air and one or more air springs containing air and connected to the air gallery via valves.

According to another aspect of the invention, there is provided a vehicle comprising the apparatus or the air suspension exhaust system.

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 1A shows a schematic representation of an apparatus for use in an air suspension exhaust system according to an embodiment of the invention with the apparatus in a closed position, and Figure 1B shows a schematic representation of the apparatus for use in the air suspension exhaust system according to an embodiment of the invention with the apparatus in an open position; Figure 2 shows a schematic representation of an air suspension system including an air suspension exhaust system according to an embodiment of the invention; Figure 3A shows a chart showing air pressure in an exhaust of a system of the prior art during venting of air through the exhaust, and Figure 3B shows a chart showing air pressure in an air exhaust system according to an embodiment of the invention during venting of air through the exhaust system according to an embodiment of the invention; and Figure 4 shows a vehicle in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

An apparatus in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 1 comprising Figures 1A and 1B. Figure 1 shows a schematic diagram of an apparatus 100 according to the invention. Figure 1A shows the apparatus 100 in a closed position, and Figure 1B shows the apparatus 100 in an open position. Figure 1 may be considered to show a cross-section of the apparatus 100. With reference to Figure 1, the apparatus 100 comprises a valve 110, an aperture 115 provided in a wall of the valve 110, a housing 120, a biasing member 130, an air inlet 140, an air outlet 160, and an exhaust channel 150 connecting the air inlet 140 to the air outlet 160. The apparatus 100 of Figure 1 may form part of a vehicle air suspension exhaust system. It should be understood that various modifications or omissions may be made to the apparatus 100 of Figure 1, as will be explained below.

The valve 110 comprises a body that is moveable between a closed position, as shown in Figure 1A, and an open position (Figure 1B). The valve 110 of Figure 1 is shown to be substantially cylindrical, but may be shaped differently. In the closed position, the valve 110 blocks the exhaust channel 150 provided between the air inlet 140 and the air outlet 160, so as to prevent passage of air through the exhaust channel 150. In the open position, the valve 110 is moved against a force exerted by the biasing member 130. In the example of Figure 1A, to move the valve 110 to the open position, the valve 110 would move upwards toward the biasing member 130 as shown in Figure 1B. The valve 110 is a moveable member, and may be held in the closed position by the biasing member 130. The biasing member 130 is configured to apply a force to the valve 110 to bias the valve 110 toward the closed position. In the example shown in Figure 1, the biasing member 130 exerts a force on the valve 110 in a direction toward the air inlet 140. In some examples, the biasing member 130 is a spring, such as a coil spring. The valve 110 is configured to engage with the biasing member 130 at a first end, as shown in Figure 1. At a second end distal to the first end of the valve 110, the valve 110 is configured to block the exhaust channel 150 in the closed position. The valve 110 may comprise a hollow body, and the hollow defined by walls of the valve 110 may define a volume or cavity.

The housing 120 of Figure 1 is shown as a plurality of wall sections which together at least partially define various cavities and openings. The wall sections may be formed as a single piece or may be formed separately and attached together. The housing 120 may be formed of any suitable material which is substantially impermeable to air, and is able to contain compressed air. In use, the apparatus 100 may contain compressed air. For example, when installed in an air suspension system of a vehicle, compressed air at a pressure of approximately 18 bar may be present in the apparatus 100. The housing 120 may be configured to house the valve 110 and the biasing member 130.

The housing 120 is shaped to define the air inlet 140. The air inlet 140 is connectable to an air suspension system of a vehicle and is configured to receive air from the air suspension system of the vehicle. For example, the air inlet 140 may comprise a connection connectable to a compressed air gallery of a vehicle, wherein a compressed air gallery is a volume provided to store compressed air and to provide compressed air to various systems of the vehicle, including air suspension systems such as air springs. The compressed air gallery may store compressed air at up to approximately 18 bar in some examples. In some examples, the air inlet 140 may receive air from a vehicle system in dependence on a venting operation of the vehicle system. That is, the air inlet 140 is configured to receive air from other vehicle systems so as to enable connected vehicle systems to reduce an air pressure of air contained in such vehicle systems.

The housing 120 is also shaped to define the air outlet 160. The air outlet 160 may comprise a connection to an external environment, such as an environment existing around a vehicle. The air outlet 160 may be connectable to an exhaust of a vehicle in some examples. The air outlet 160 may optionally connect the apparatus 100 to the external environment via a silencer.

The silencer may be configured to reduce a noise associated with air passing through the air outlet 160 or through the exhaust.

The housing 120 is also shaped to define an exhaust channel 150, shown in Figure 1 as a dashed line. The exhaust channel 150 is configured to connect the air inlet 140 to the air outlet 160, such that the exhaust channel 150 provides a channel for air, or compressed air, to move from the air inlet 140 to the air outlet 160 such that air may be received from a connected compressed air system of a vehicle through the air inlet 140 and may exit the apparatus 100 through the air outlet 160 after passing through the exhaust channel 150. Air which passes through the exhaust channel 150 may be known as exhaust air. The exhaust channel 150 of Figure 1 comprises a first portion 151 and a second portion 152, but may be a channel divisible into any number of portions, suitable for directing air from the air inlet 140 to the air outlet 160.

The first portion 151 of the exhaust channel 150 is configured to connect to the air inlet 140.

The second portion 152 of the exhaust channel 150 is configured to connect to the air outlet 160. Although the first portion 151 and the second portion 152 are shown in Figure 1 to comprise tapered or narrowing sections of the exhaust channel 150, the invention is not limited thereto and the exhaust channel 150 and each portion thereof may comprise any suitable shaped channel for directing air from the air inlet 140 to the air outlet 150. The first portion 151 of the exhaust channel 150 is connected to the second portion 152 of the exhaust channel 150 when the valve 110 is in the open position as in Figure 13, and is not connected when the valve 110 is in the closed position as in Figure 1k As discussed above, the valve 110 is moveable between a closed position (shown in Figure 1A) and an open position (shown in Figure 1B). In the closed position, the valve 110 blocks the exhaust channel 150 so as to prevent the passage of air from the air inlet 140 to the air outlet 160. In the open position, air may flow freely from the air inlet 140 through the exhaust channel 150 to the air outlet 160. The valve 110 may be considered to be in a partially open position as it moves between the open position and the closed position. In a partially open position, air may move through the exhaust channel 150 at a reduced rate compared to when the valve 110 is in a fully open position.

The apparatus 100 may further comprise a pilot outlet 170 to a pilot channel or a pilot valve.

The pilot outlet 170 to the pilot channel or pilot valve may comprise a connection between the air inlet 140 and a pilot valve. The pilot valve, discussed in more detail in relation to Figure 2, may comprise a valve operable to open and close so as to allow or prevent passage of air through a pilot channel. The apparatus 100 further comprises a pilot inlet 175 configured to receive air through the pilot channel when the pilot valve is open.

The apparatus 100 comprises a first cavity 180 and a second cavity 185. The first cavity 180 and the second cavity 185 comprise volumes which are at least partially defined by the housing 120 and the valve 110. The first cavity 180 and the second cavity 185 may be configured to receive and store air, and may be sealed to contain air except for means for ingress of air into the first cavity 180 and the second cavity 185 discussed below.

The first cavity 180 is at least partially defined by the valve 110 and the housing 120, and is provided to an area inside or behind the valve 110. The first cavity 180 may house the biasing member 130. The first cavity 180 is positioned such that when pressurised air is received into the first cavity 180, an increase in air pressure in the first cavity 180 resulting from the received air acts to apply a force on the valve 110 in a direction substantially the same as a direction in which the force is applied to the valve 110 by the biasing member 130. The first cavity 180 is connected to the exhaust channel 150 by the aperture 115. The first cavity 180 may be at least partially defined by a hollow interior volume of the valve 110.

The second cavity 185 is at least partially defined by the valve 110 and the housing 120, and in an example is provided to an area surrounding the valve 110. The second cavity 185 comprises a connection to the pilot inlet 175, and is configured to receive air from the pilot inlet 175 in dependence on the pilot valve being open. The second cavity 185 is positioned such that when air is received into the second cavity 185 from the pilot inlet 175, an increase in air pressure in the second cavity 185 resulting from the received air acts to apply a force on the valve 110 in a direction substantially opposite to the direction of the force applied to the valve 110 by the biasing member 130. The valve 110 is moveable to the open position from the closed position by the force applied by the increased air pressure in the second cavity 185. That is, when sufficient air is received into the second cavity 185 from the pilot inlet 175, the force exerted on the valve 110 by the increased air pressure in the second cavity 185 is sufficient to overcome the force exerted on the valve 110 by the biasing member 130 and move the valve 110 from the closed position to the open position.

The apparatus may further comprise at least one first sealing member 191 and at least one second sealing member 192. The at least one first sealing member 191 and the at least one second sealing member 192 may be provided to respectively seal the first cavity 180 and the second cavity 185. The at least one first sealing member 191 and the at least one second sealing member 192 may comprise 0-rings configured to block holes or gaps between the valve 110 and the housing 120, so as to further seal the first cavity 180 and the second cavity 185 against unwanted egress of air.

As explained above, the valve 110 is biased toward the closed position by the biasing member 130. The second cavity 185 may receive air through the pilot inlet 175, and an increased air pressure in the second cavity 185 exerts a force acting against the force of the biasing member 130. When the force exerted by the air pressure in the second cavity 185 exceeds the force exerted by the biasing member 130, the valve 110 begins to move from the closed position to the open position. As the valve 110 moves toward the open position, exhaust air is allowed to pass from the air inlet 140 through the exhaust channel 150. As the air passes from the first portion 151 of the exhaust channel 150 to the second portion 152 of the exhaust channel 150, toward the air outlet, the exhaust air reaches the aperture 115. At this stage, the exhaust air may pass through the aperture 115 into the first cavity 180. The exhaust air entering the first cavity 180 results in an increase in an air pressure of the first cavity 180, which exerts a force on the valve 110 in substantially the same direction as the force exerted by the biasing member 130. In other words, the exhaust air entering the first cavity 180 through the aperture 115 results in a force opposing the movement of the valve 110 from the closed position to the open position. This causes a speed at which the valve 110 opens to be reduced, but does not reduce a maximum flow rate of air through the exhaust channel 150 when the valve 110 is fully open.

The use of air to slow the opening of the valve 110 may be known as pneumatic damping of the valve 110.

The valve 110 is subject to various forces as it moves from the closed position to the open position. In particular, in the closed position, a force exerted by the biasing member 130 on the valve 110 toward the closed position is greater than a force exerted on the valve 110 by pressurised air proximal to the air inlet 140. When the pilot valve is opened, air enters the second cavity 185 from the pilot inlet 175, and exerts a force on the valve 110 which biases the valve 110 toward the open position. Once sufficient air pressure is achieved in the second cavity 185, the force exerted by the pressurised air on the valve 110 is greater than the force exerted by the biasing member 130 and the valve 110 begins to move toward the open position. At this stage, air is able to pass through the aperture 115 into the first cavity 180 and exerts a force on the valve 110 opposing the force exerted by air in the second cavity 185, thereby slowing the opening of the valve 110. The force exerted by the air in the second cavity 185 is greater than the combined forces exerted by air in the first cavity 180 and by the biasing member 130 and the valve 110 moves to a fully open position. The valve 110 moves from the open position to the closed position when the force exerted by the biasing member 130 exceeds the force exerted by air in the second cavity 185.

When the valve 110 is in at least a partially open position and air is moving from the air inlet to the air outlet 160 through the exhaust channel 150, the moving exhaust air will also exert a force on an end of the valve 110 proximal to the air inlet 140, in a direction substantially opposing the force exerted by the biasing member 130. Depending on a flow rate of the exhaust air and relative air pressures, the force exerted by the moving exhaust air on the valve 110 may be negligible or may contribute to maintaining the valve 110 in the open position. In one embodiment, the force exerted on the end of the valve 110 proximal to the air inlet 140 is significantly less than the force exerted on the valve 110 by the air in the second cavity 185.

Advantageously, by slowing the opening of the valve 110, a noise associated with the opening of the valve 110 due to a rapid release of air through the air outlet 160 and a high peak pressure of air exiting the air outlet 160 as a result of a high pressure differential between air receive from the air inlet 140 and air in the external environment may be reduced. This is achieved by the apparatus 100 of Figure 1 without reducing an operating pressure of a vehicle system and without reducing a maximum flow rate through the exhaust channel 150, thereby ensuring that the vehicle systems may still operate as desired and venting of air from said systems is still fast, while reducing the noise associated with the venting operation. In addition, exhaust air, that is air which is already intended to be passing through the exhaust channel to vent the system, is used for the pneumatic damping, and therefore a more controlled opening of the valve 110 is achieved without need for dedicated air supply or control.

The aperture 115 comprises a hole provided through a wall of the valve 110. Although a single aperture 115 is shown in Figure 1, the apparatus 100 may comprise one or more further apertures. For example, a plurality of apertures may be provided around an outer wall of the valve 110, and may connect the exhaust channel 150 to the first cavity 185 at various positions. The aperture 115 may comprise a hole having a substantially circular cross-section, which may have a diameter of approximately 0.5-2.5mm. In other examples, the aperture 115 may have a different shape. The aperture 115 may define a passage through the wall of the valve 110 having an approximate length of 1mm to 3mm. The aperture 115 may be aligned so as to provide a channel through the wall of the valve 110 that is perpendicular to the wall of the valve 110, so as to define as short a channel through the wall of the valve 110 as possible, or may be inclined with respect to the surface of the wall of the valve 110.

The aperture 115 of Figure 1 is provided to connect the first cavity 180 to a part of the exhaust channel 150 proximal to the first portion 151, or proximal to the air outlet 160, facing toward the air outlet 160. However, the aperture 115 may be provided on any location of the valve 110 which connects the first cavity 180 to the exhaust channel 150 such that when the valve 110 moves toward the open position, exhaust air passing through the exhaust channel 150 from the air inlet 140 can enter the first cavity 180. As shown in Figure 1B, when the valve 110 is in the open position, air can flow from the air inlet 140 along the exhaust channel 150 and through the aperture 115 into the first cavity 180.

Figure 2 shows a diagram representing an air suspension system 200 for compressed air venting of a vehicle according to an embodiment of the invention. Although not shown in Figure 2, the system 200 of Figure 2 may be installed in a vehicle in use.

The system 200 of Figure 2 comprises a compressed air gallery 210, a front valve block 220 connected to front air springs 221, a rear valve block 220 connected to rear air springs 221, an exhaust slave valve 240, an exhaust pilot valve 242, a silencer 241, a compressor 250 and one or more compressed air reservoirs 260. The system 200 of Figure 2 may in some embodiments include further components or may omit some of the components shown. Although not shown, the system 200 of Figure 2 may comprise a controller or be communicatively coupled with a controller. The exhaust slave valve 240 may be the apparatus 100 of Figure 1.

In the example of Figure 2, the system 200 comprises a compressed air gallery 210. The compressed air gallery 210 may be considered a first volume. The compressed air gallery 210 is a volume configured to store compressed air at up to a first pressure. The compressed air gallery 210 is selectively coupled with the compressor 250, the exhaust slave valve 240, the exhaust pilot valve 242, the front valve block 220 and the rear valve block 220. The compressed air gallery 210 is configured to store compressed air and to provide compressed air to vehicle systems including the air spring blocks of Figure 2. In other words, the compressed air gallery 210 is a central volume used for delivery and control of compressed air to pneumatic vehicle systems including air suspension springs. The compressed air gallery 210 is configured to store compressed air at a first pressure, the first pressure being greater than an air pressure of an external environment. In certain examples, the first pressure may be up to approximately 18 bar. The compressed air gallery 210 may have a volume of 1 litre. In one example, the compressed air gallery 210 has a volume of up to 0.51. In another example, the compressed air gallery 210 has a volume of 0.31.

The system 200 of Figure 2 includes a front valve block 220. The front valve block 220 may be positioned near a front end of a vehicle in use. For example, the front valve block 220 may be provided near an end of a vehicle proximal to a vehicle engine, and may be provided proximal to an underside of the vehicle. However, it should be understood that the position and function of the front valve block 220 is not limited thereto, and that the front valve block 220, and more specifically the front air springs 221, are provided as an example of a second volume to which the first volume may be vented.

The front valve block 220 comprises one or more first valves 222. Although Figure 2 illustrates there being two first valves 222 in the front valve block 220, a different number of valves 222 may be present. The first valves 222 connect the compressed air gallery 210 to front air springs 221 via a first compressed air channel 222. The first valves 222 are configured to be operable to open and close so as to respectively allow or deny the passage of compressed air between the compressed air gallery 210 and the front air springs 221. The front air springs 221 are operable with compressed air at a second pressure. The second pressure may be lower than the first pressure of the compressed air gallery 210, such that when the first valves 222 are open, compressed air flows from the compressed air gallery 210 to the front air springs 221 as a result of the pressure being greater in the compressed air gallery 210 than in the front air springs 221.

The front air springs 221 are configured to be filled with compressed air as part of a vehicle air suspension system. The front air springs 221 may therefore comprise a volume for storing compressed air at the second pressure. Figure 2 illustrates the system 200 as comprising two front air springs 221, one to be provided on a left side of a vehicle and one to be provided on a right side of the vehicle. However, the system 200 is not limited thereto, and any number of front air springs 221 may be present.

The system of Figure 2 further comprises the rear valve block 230. The rear valve block 230 is similar to the front valve block 220, but may be provided proximal to a rear end of a vehicle in use. The rear valve block 230 may comprise one or more second valves 232 connecting the compressed air gallery 210 to one or more rear air springs 231 via a second compressed air channel 232. The rear valve block 230, the one or more second valves 232, the one or more rear air springs 231 and the second compressed air channel 232 may respectively be similar to the front valve block 220, the one or more first valves 222, the one or more front air springs 221 and the first compressed air channel 222, and therefore a detailed description of each is omitted. However, these parts should be considered similar to the corresponding parts of the front valve block 220 discussed above.

The rear air springs 231 may operate and be configured to store compressed air at the second pressure, the same as the front air springs 221. In some embodiments, the rear air springs 231 may operate at and be configured to store compressed air at a third pressure, different to the second pressure. The third pressure may be lower than the second pressure, or may be greater than the second pressure. The third pressure and the second pressure are both lower than the first pressure of the compressed air gallery 210, and greater than an air pressure of the external environment. In some examples, the first pressure is up to approximately 18 bar, the second pressure is between approximately 6 and 8 bar, and the third pressure is between approximately 4 and 10 bar. As with the front valve block 220, when the second valves 232 are opened, compressed air can flow from the compressed air gallery 210 to the rear air springs 231 due to a pressure differential between the compressed air gallery 210 at the first pressure and the rear air springs 231 at the second pressure or the third pressure.

The rear valve block 230 of Figure 2 is connected to a compressed air reservoir 260 by a reservoir valve 261. However, the reservoir 260 may alternatively be connected to a different part of the system 200, for example to the compressed air gallery 261 or the front valve block 220 by a different valve. The reservoir 260 is configured to store compressed air, and may be configured to store compressed air to be transferred to the air springs via the compressed air gallery 210. In certain embodiments, the reservoir 260 may have a volume of up to 12 litres, and in some examples the reservoir 260 may have a volume between 2 and 10 litres. The reservoir 260 may store compressed air at the first pressure. In some examples, the system 200 may comprise more than one reservoir 260. For example, the reservoirs may comprise a first reservoir having a volume of approximately 2.7 litres and a second reservoir having a volume of approximately 9 litres.

The rear valve block 220 of Figure 2 is also shown to comprise a pressure transducer 270. The pressure transducer 270 is configured to provide feedback to a control system (not shown) and is pneumatically connected to the compressed air gallery 210. For example, the pressure transducer 270 may measure the pressure of the compressed air gallery 210 and provide an analog or digital signal to the control system indicative of the pressure of the compressed air gallery 210. It should be understood that the pressure transducer 270 may be provided at a different position within the system 200.

The system 200 of Figure 2 further comprises an exhaust slave valve 240. The exhaust slave valve 240 is configured to selectively connect the compressed air gallery 210 to the external environment. The exhaust slave valve 240 is operable to open and close so as to respectively allow or deny the passage of compressed air from the compressed air gallery 210 to the external environment. In some examples, the exhaust slave valve 240 is connected to the external environment via a silencer 241 which is configured to decrease a noise associated with compressed air passing through the exhaust slave valve 240. The exhaust slave valve 240 may be the apparatus 100 of Figure 1, and may comprise an aperture 115 provided in a wall of the valve 110 to pneumatically dampen the valve 110 and slow the opening of the exhaust slave valve 240.

The system 200 of Figure 2 comprises an exhaust pilot valve 242. The exhaust pilot valve 242 may be an electrically operable solenoid valve, configured to open and close in dependence on a control signal. The exhaust pilot valve 242 is configured to control passage of air through a pilot channel, which when the exhaust pilot valve 242 is open, may connect between the pilot outlet 170 and the pilot inlet 175 of Figure 1. In other words, the exhaust pilot valve 242 may be configured to control delivery of air to the second cavity 185.

The system 200 of Figure 2 further comprises a compressor 250. The compressor 250 is configured to intake air, to compress the intake air and to provide the compressed air to the compressed air gallery 210. The compressor 250 may be a compressor of any known type which is suitable for compressing air to add into the system 200. For example, the compressor 250 may comprise a fixed displacement compressor or a variable displacement compressor.

The system 200 may further comprise a dryer 252 configured to dry intake air, a motor 252 to drive the compressor 250, a filter 251 to filter intake air to remove particulates from intake air, and a fixed restriction 254 to control a flow rate of air from the compressor 250 into the compressed air gallery 210.

The system 200 of Figure 2 may be installed on a vehicle in use. In use, the compressed air gallery 210, the front air springs 221 and the rear air springs 221 may store compressed air. In certain situations, it may be necessary or desirable to remove compressed air from the system 200, or from parts of the system 200. For example, it may be necessary or desirable to remove compressed air from the compressed air gallery 210. Removing compressed air from a volume may be known as decompression of the volume.

Decompression of a part of the system 200 of Figure 2 may be performed as a result of identifying a trigger event for decompression. For example, the compressed air gallery 210 may be vented to remove compressed air from the compressed air gallery 210 and to thereby decompress the compressed air gallery 210. A trigger event for decompression may include a determination that new or more compressed air is to be added to the system 200. In this example, to optimally operate the compressor 250 to add compressed air to the compressed air gallery 210, it may be necessary or desirable to reduce the pressure of the compressed air gallery 210 prior to operating the compressor 250. For example, it may be desirable to reduce the pressure of the compressed air gallery 210 to near the air pressure of the external environment. In another example, a change in vehicle ride height may be a trigger event for decompression of the compressed air gallery 210. The change in vehicle ride height may be determined by an air suspension vehicle to accommodate a change in road surface, or may be requested by a user input.

The system 200 may comprise control means to control the system 200 in dependence on the trigger event for decompression. If a trigger event for decompression of the compressed air gallery 210 is determined, the system 200 may control to vent the compressed air gallery 210 by controlling the exhaust pilot valve 242 to open the exhaust slave valve 240.

According to an embodiment of the invention, the compressed air gallery 210 may be vented to the external environment through the exhaust slave valve 240, by operating the exhaust pilot valve 242 to supply air to the second cavity 185 to open the exhaust slave valve 240. The exhaust slave valve 240 may be opened for a pre-determined period of time or until the air pressure in the compressed air gallery 210 reaches a target pressure. A noise associated with venting the system 200 is reduced by the pneumatic damping of the exhaust slave valve 240 by the provision of an aperture 115 in a wall of a valve 110.

Figures 3A and 3B show graphs of pressure at different points in an exhaust system during venting, plotted over time. Figure 3A shows a graph of pressures in a known system which does not comprise an aperture configured to pneumatically dampen an opening of a valve, and Figure 3B shows a graph of pressures in a system according to an embodiment of the invention, such as the apparatus 100 of Figure 1 comprising the aperture 115 to pneumatically dampen the opening of the valve 110. In both Figure 3A and 3B, a first pressure, P1, 310, 330, and a second pressure. P2, 320, 340, are plotted against time after a venting process is initiated. The first pressure 310, 330, is measured at a position between an exhaust and a pressure source. The first pressure 310, 330 is indicative of a pressure of a volume for storing compressed air in a system in use. For example, the first pressure 310, 330 may be considered to represent a pressure at the air inlet 140 of Figure 1, or the compressed air gallery 210 of Figure 2. The second pressure 320, 340 is measured between an exhaust valve and an external environment, and is indicative of a pressure of exhaust air moving through an exhaust channel. For example, the second pressure 320, 340 may be considered to represent a pressure at the air outlet 160 of Figure 1 or between the exhaust slave valve 240 and the silencer 241 of Figure 2.

In both Figures 3A and 3B, the first pressure 310, 330 is increased until it reaches a pre-determined level. When the first pressure reaches the pre-determined level, an exhaust valve is opened and venting begins. For example, considering the apparatus 100 of Figure 1, once the pre-determined pressure level is reached, a pilot valve may be opened to enable air to enter the second cavity 185 to open the valve 110. As can be seen in Figure 3A, in a conventional system comprising a valve which is not pneumatically dampened, the second pressure 320 rises sharply to a peak and then gradually decreases. The first pressure 310 also decreases until venting is complete. The sharp increase in the second pressure 320 represents a fast opening of an exhaust valve due to the high pressure differential on either side of the valve, i.e., between the first pressure 310 and the second pressure 320 when the first pressure 310 reaches the pre-determined level. This sharp increase is associated with a high noise which is perceptible by a user or nearby persons and is undesirable.

Figure 3B shows the first pressure 330 and the second pressure 340 in a similar situation, but in relation to an apparatus 100 or air exhaust system according to the invention. In this case, when the first pressure 330 reaches the pre-determined level, the exhaust valve such as the valve 110 of Figure 1 is opened. However, due to the pneumatic damping achieved by the provision of the aperture 115, the speed at which the valve 110 opens is reduced. This can be seen by inspection of the second pressure 340 of Figure 3B, which defines a significantly smoother curve compared to the second pressure 320 of Figure 3A. This smoother curve and lower peak of the second pressure 340 of Figure 3B is indicative of a slower opening of the exhaust valve and of a significant reduction in associated noise. In addition, a total time for venting, indicated by a time for the first pressure 330 to fall from the pre-determined level to approximately zero, is similar to the total time for venting of the prior art system shown in Figure 3A. Therefore, noise associated with venting is reduced without significant compromise on a venting time, by pneumatically damping a valve to reduce the speed at which the valve opens without reducing a maximum flow rate of air through the valve.

Figure 4 illustrates a vehicle 400 according to an embodiment of the present invention. The vehicle 400 comprises an apparatus 100 according to Figure 1, or the air suspension system 200 of Figure 2 comprising the apparatus 100 of Figure 1 as the exhaust slave valve 240. Advantageously, by using the apparatus 100 of Figure 1 with an air suspension exhaust system in a vehicle 400, pneumatic damping of an exhaust valve is achieved without requiring an addition of extra parts or components which may add weight and reduce performance of a vehicle, as well as add complexity to the system. Instead, by providing the aperture 115 of Figure 1 to the valve 110, the valve 110 can be controlled to open gradually so as to reduce noise. Further, this solution does not require modification to existing exhaust valve properties, for example a spring force of the biasing member 130 of Figure 1 may be maintained at a normal level, and the apparatus according to the invention therefore does not interfere with an exhaust valve operating as a pressure relief valve to automatically open in case of excessive system pressure.

It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS1. An apparatus for use in an air suspension exhaust system, the apparatus comprising: a valve shaped at a first end to engage with a biasing member and enclosing a first cavity at least partially defined by the valve; and a housing configured to house the valve and the biasing member, the housing comprising: an air inlet; an air outlet; and an exhaust channel provided between the air inlet and the air outlet; wherein the valve is movable between a closed position in which the valve blocks passage of air through the exhaust channel and an open position in which air can pass through the exhaust channel; and wherein the valve comprises an aperture provided through a wall of the valve so as to allow air that flows through the exhaust channel from the air inlet to the air outlet in dependence on a position of the valve into the first cavity.
2. The apparatus of claim 1, wherein when the valve is in the open position, air is permitted to pass from the air inlet through the exhaust channel and the aperture into the first cavity, and when the valve is in the closed position, air is not permitted to pass from the air inlet through the exhaust channel and the aperture.
3. The apparatus of claim 1 or claim 2, wherein the exhaust channel comprises a first portion connected to the air inlet and a second portion connected to the air outlet; and wherein the first portion and the second portion are selectively connected in dependence on the position of the valve.
4. The apparatus of claim 3, wherein the aperture is provided through an area of the wall of the valve proximal to the air outlet to connect the second portion of the exhaust channel to the first cavity.
5. The apparatus of any of claims 3 or 4, comprising one or more further apertures configured to allow air flow between the second portion of the exhaust channel and the first cavity.
6. The apparatus of any preceding claim, comprising a pilot inlet configured to direct air into a second cavity, the second cavity surrounding at least a portion of the valve and at least partially defined by the portion of the valve and the housing, such that, when air enters the second cavity from the pilot inlet, an air pressure in the second cavity is increased to act against the force of the biasing member to move the valve toward the open position.
7. The apparatus of claim 6, comprising at least one second sealing element provided on a surface of the valve to seal at least one gap between the valve and the internal surface of the housing to enclose the second cavity to thereby contain air in the second cavity.
8. The apparatus of any of claims 6 to 7, wherein the apparatus is a slave valve configured to open and close in dependence on movement of air through the pilot inlet.
9. The apparatus of any preceding claim, wherein the aperture has a substantially circular cross-section.
10. The apparatus of claim 9, wherein the aperture has a diameter of between approximately 0.5mm and 2.5mm.
11. The apparatus of any preceding claim, wherein the aperture defines a channel for air through the wall of the valve and wherein the aperture has a length of approximately 1mm to 20 3mm.
12. The apparatus of any preceding claim, wherein the first cavity is configured to at least partially house the biasing member.
13. The apparatus of any preceding claim, wherein the first cavity is enclosed by the valve and the housing.
14. The apparatus of any preceding claim, comprising at least one first sealing element provided on a surface of the valve to seal at least one gap between the valve and an internal surface of the housing to enclose the first cavity to thereby contain air in the first cavity.
15. The apparatus of any preceding claim, wherein the valve is substantially hollow; and wherein the first cavity comprises a volume at least partially defined by the hollow.
16. The apparatus of any preceding claim, wherein the biasing member comprises a spring configured to bias the valve toward the closed position.
17. The apparatus of any preceding claim, wherein the air inlet comprises a connection for connecting the apparatus to an exhaust system containing air.
18. An air suspension exhaust system for use in an air suspension system of a vehicle, the air suspension exhaust system comprising: the apparatus of any preceding claim; and at least one volume configured to store air and configured to be connected to the air inlet.
19. The air suspension exhaust system of claim 18, wherein the at least one volume comprises at least part of an air suspension system.
20. The air suspension exhaust system of claim 19, wherein the air suspension system includes an air gallery containing air and one or more air springs containing air and connected to the air gallery via valves.
21. A vehicle comprising the apparatus of claim 1 to 17 or the air suspension exhaust system of claims 18 to 20.