GB2590681A

GB2590681A - Vehicle cabin ventilation

Info

Publication number: GB2590681A
Application number: GB1919246.7A
Authority: GB
Inventors: Alan Harris Roy; Pinkstone Adam; Edward Pendleton Tomasz; Edward Poulton Roy
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2021-07-07
Anticipated expiration: 2039-12-23
Also published as: WO2021130467A1; GB201919246D0; GB2590681B

Abstract

A vehicle has a passenger cabin and a ventilation system (10, figure 1A) including a vent 40 to discharge air into the cabin. The air may be heated or cooled. The vent comprises a housing 43,55 defining a vent inlet 51, vent outlet 42 and a chamber therebetween. A flow divider 60 splits the chamber into first and second passages 46,47 and includes a trailing edge at which the passages converge. A valve 50 located upstream of the flow divider is moved (e.g. rotated) relative to the flow divider to control the proportion of air flows ‘A1’,‘A2’ in the passages and so determine the direction of a combined outward flow ‘A’. At least a two millimetre (2 mm) gap ‘G’ separates the valve and flow divider throughout the range of movement of the valve, which ideally prevents whistling noises. The gap is ideally not more than 5 mm. The vent outlet may be a curved, elongate slot that follows the curvature of a dashboard it is in to extend across a width of the cabin. The flow divider extends the length of the vent outlet.

Description

VEHICLE CABIN VENTILATION

Field of the Invention

The present invention relates to a vehicle comprising a passenger cabin and a ventilation system for ventilating the passenger cabin.

Background of the Invention

Passenger vehicles are generally provided with a ventilation system to supply air into the cabin. The ventilation system generally comprises a system for preparing conditioned air (which is generally external air which has been filtered and/or heated and/or cooled and/or dehumidified as required) such as a heating, ventilation, air-conditioning (HVAC) system At least one blower may direct the conditioned air, via associated air ducts, to a plurality of outlet vents distributed about the cabin The vents and/or the airflow supplied to the outlets may generally be user adjustable The positioning and control of cabin air flow can have a direct impact on vehicle occupant comfort and resulting perception of the vehicle. Accordingly, it is desirable to provide air outlets distributed throughout the cabin at convenient locations, for example proximal to vehicle occupant seating positions. There is also a need to provide vents which provide both an adjustable or directable airflow. For both aesthetic reasons and packaging, it is advantageous to provide vents with a simple outlet arrangement and, as such, the use of vents which are able to provide flow vectoring or pseudo-oscillation of the outcoming airflow are desirable.

Summary of the Invention

The present invention provides a vehicle comprising a passenger cabin and a ventilation system for ventilating the passenger cabin, the ventilation system comprising a vent for discharging air into the passenger cabin, wherein the vent comprises: a housing having an inlet, an outlet, and a chamber communicating the inlet with the outlet, a flow divider located in the chamber dividing the chamber into a first passage and a second passage, the flow divider having a trailing edge upstream of the outlet extending the length of the outlet, the first and second passages converging at the trailing edge of the flow divider, a valve located upstream of the flow divider for apportioning airflow between the first and second passages, wherein the valve is movable relative to the flow divider through a range of movement for adjusting the apportionment of airflow between the first and second passages, and the valve and the flow divider are separated by a gap of at least 2 millimetre throughout the range of movement of the valve.

First and second airflows along the first and second passages converge at the trailing edge of the flow divider, and are discharged through the outlet as a combined airflow. Vents of this type are often known as 'colliding jet' vents. The valve controls the relative flow rates of airflows through the first and second passages by throttling one or each of the passages, and thereby allows adjustment of the trajectory of the airflow into the cabin. For vents of this type it is conventionally an objective to minimise any gap between the valve and the flow divider. Minimising the gap reduces leakage of unmetered airflow between the passages and thereby enables most precise control of the flow rates of the airflows. However, the present inventors have observed that where the gap between the valve and the flow divider is very small, acoustic whistling and other undesirable acoustic effects can occur as a result of airflow passing through the narrow gap. These undesirable acoustic effects can tend to be most prominent where, during the range of movement of the valve, a trailing edge of the valve sweeps past a leading edge of the flow divider. In this configuration, the gap is smallest at a dead-centre position of the valve.

The present invention addresses the above problem by increasing the separation between the valve and the flow divider such that, throughout the range of movement of the valve, a gap, i.e. an empty space through which airflow may pass, between the valve and the flow divider of at least 2 millimetres is always present. In other words, even at a closest position of the valve to the flow divider, the gap therebetween is always at least 2 millimeter. Considering the above example of a valve where a trailing edge of the valve sweeps past a leading edge of the flow divider, in the invention at the dead-centre position of the valve the gap between a trailing edge of the valve and a leading edge of the flow divider would be at least 2 millimetre. It has been observed by the present inventors that a gap of at least 2 millimetre advantageously reduces acoustic whistling and other acoustic effects. It is recognised however that this benefit comes at a cost of reduced control of the airflow rates along the first and second passages.

The gap may be constant throughout the range of movement of the valve. In other words, the valve may be configured such that the gap to the flow divider does not change even as the valve is moved. For example, the valve could rotate about a central axis. The tone of acoustic noise generated by air passing through the gap is a function of the size of the gap. Maintaining the gap constant may thus advantageously avoid change in acoustic tone as the valve moves. A constant acoustic tone may be less perceptible by an occupant of the passenger cabin than a changing acoustic tone. Cabin occupant comfort may thereby be improved. In contrast, a gap that changes with movement of the valve could undesirably result in generation of different acoustic tones.

The gap may be constant across the span of the valve. The valve spans across a region upstream of the flow divider for intercepting airflow. For example, the valve may be located in the chamber, and the valve may span across the chamber. Maintaining the gap constant across the span of the valve may advantageously avoid generation of a broad range of acoustic tones. A narrow range of acoustic tones may be less perceptible by an occupant of the passenger cabin than a broad range of acoustic tones. Cabin occupant comfort may thereby be improved. In contrast, a gap that varied in size across the span of the valve could undesirably result in generation of broadband acoustic noise.

The flow divider may have a leading edge, the valve is located adjacent a section of the leading edge, and the section of the leading edge is straight. In this arrangement, the valve is located adjacent a leading edge of the flow divider and is movable relative to the flow divider for regulating airflow over the flow divider. Because the leading edge of the flow divider is straight, the axis about which the valve moves may correspondingly be straight. This may simplify the construction of the valve. The section of the leading edge could comprise only a part of a length of the leading edge, or alternatively could comprise a full length of the leading edge.

The valve may be mounted for rotation about an axis, and the axis may be parallel to the straight section of the leading edge. This arrangement may advantageously simplify construction of the valve.

The gap may be at least 3 millimetre or at least 4 millimetre. A gap of at least 3 millimetre or even at least 4 millimetre may advantageously best minimise acoustic whistling and/or other undesirable acoustic effects.

As noted above however, the gap between the valve and the flow divider may disadvantageously allow leakage of airflow across the flow divider, and a large gap will typically allow a greater degree of leakage. It has been found that in many applications a most desirable balance between reduced acoustic whistling and acceptably low leakage of airflow is achieved where at a closest position of the valve to the flow divider, i.e. at a position of the valve where the gap is least, the gap is no greater than 10 millimetre.

Accordingly, the vent may be configured such that at a closest position of the valve to the flow divider the gap is no greater than 10 millimetre, or even no greater than 5 millimetre. The gap is therefore preferably in the range of 2 millimetre to 10 millimetre, or even more preferably in the range of 2 millimetre to 5 millimetre.

The ventilation system may further comprise a blower for supplying an airflow to the vent.

Brief Description of the Drawings

In order that the present invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an illustrative view of a vehicle including a vehicle ventilation system; Figure 2 is a forward-facing view of a vehicle cabin including a slot vent; Figure 3 is a perspective view of a slot vent, Figure 4 is top view through a dashboard incorporating a vent assembly; Figure 5 is a cross section through the vent assembly of figure 5, Figure 6 is a perspective cross section through another vent assembly, and Figure 7 is a schematic representation of a top view of a vent assembly.

Detailed Description of the Invention

Figure I shows a vehicle 1 having a passenger cabin 2 and a vehicle ventilation system 10 for supplying air to the cabin 2. The configuration of the vehicle is for example purposes only but shows a six-seat configuration with the seating arranged in three rows, each row including two seats 5. Such a seating configuration may, for example, be used in a "sports utility vehicle' (or "SUV"). The vehicle may for example be an electric vehicle (an "EV") and, whilst it will be appreciated that the present disclosure is not limited to such vehicles, the skilled person will be aware that the type of drive system may result in specific packaging or configuration requirements for the vehicle ventilation system 10.

The vehicle ventilation system 10 receives air from outside of the vehicle 1 and conditions the air before distributing it around the cabin 2. The vehicle ventilation system 10 may include an air supply having an intake 11 and a heating and cooling system 20 (which may be a heating, ventilation, air-conditioning ("EIVAC") system of a type generally known in the art). The heating and cooling system 20 may include a blower 22 and at least one heating element 24 (which may be a heat exchanger).

The vehicle ventilation system 10 may further include an air distribution system to direct air from the supply to the to the vehicle cabin For example, the air distribution system may include a plurality of vents 30, 40 positioned in different cabin locations and in fluid communication with the air supply via appropriate ducts 25.

In accordance with embodiments of the invention, the vents may include at least one vent assembly 40 which is formed with a vent 42 in the form of an elongate slot 42. As seen in the forward-facing interior view of the cabin 2 of Figure 2, the vent 40 may be positioned within the dashboard 4 of the vehicle. For example, the vent 40 may be arranged to extend along at least a portion of the dashboard 4 in the transverse direction relative to the vehicle 1. In the present context the vent 42 is defined as a slot as it has a generally elongate profile with a relatively long and narrow aperture. The slot 42 has a length 1 which is much greater than its height h. This may be contrasted with many existing car ventilation vent arrangements which may have a compact broad profiled shape (such as a polygonal or elliptical or complex shape with a ration of width-to-height, or height-to-width, which is less than 4:1).

Whilst a slot shaped vent 42 may be desirable for purely aesthetic reasons, a particular advantage in embodiments of the invention (as will be explained further below) is the ability to provide a cabin air supply assembly 40 which can vector the airflow perpendicular to the plane of the vent 42. As shown schematically in Figure 3, the general direction as shown by arrow A of airflow expelled from the slot 42 is perpendicular to the plane of the slot and extends along the full length of the slot. The airflow may be controllable to deflect the effective airflow upward or downward relative to the flow direction as indicated by arrow V. For aesthetic and/or packaging reasons it is known to provide a dashboard 4 which is curved along its length. For example, as seen in Figure 1A, 4 and 7, when viewed from above the dashboard may be curved forwardly and/or rearwardly along its transverse length (i.e. the length across the vehicle and parallel to the vehicle axles). It is, therefore, desirable that the vent 42 is able to follow the curvature of the dashboard 4. In particular, it may be advantageous to provide a vent 42 which is an elongate slot having a concave curvature which curves inwardly away from the passenger seating location. Such an arrangement may provide a vent 42 which partially wraps around the seating location such that the outward airflow A is focussed towards the passenger. In order to optimise the performance of the vent 42 and avoid unnecessary turbulence and/or pressure losses, embodiments of the invention are specifically adapted for the use of such a curved outlet profile.

A cross-sectional view, through section S-S of Figure 4, is shown in Figure 5. The air supply assembly 40 comprises a valve 50, for example a barrel valve, in a valve housing 55 and having an inlet 51 at its rearward (with respect to the airflow) end. The inlet 55 is in fluid communication with the heating and cooling system 20 to receive a flow of conditioned air, as indicated by arrow F, for supplying to the cabin 2. The forward end of the valve housing 55 is connected to, and contiguous with, the rearward end of the body 43 of the vent. The valve 50 further comprises a valve actuator 54 (which may be mounted externally to the housing 55) connected to a valve element 52, in the form of a vane extending across the width of the valve 50, via a drive shaft 53.

The body 43 of the vent assembly 40 extends forwardly from the valve 50 to the vent 42. As the vent 42 is wider than the valve 50 in the transverse direction, it may be noted that the side walls 43a and 43b of the housing diverge along the flow wise length of the vent assembly 40. The housing includes a flow divider 60 positioned between the valve 50 and the outlet 42. The flow divider 60 and body 43 together define a first (upper) flow channel 46 and a second (lower) flow channel 47 extending from the valve 50 to the outlet 42. As such the flow of conditioned air is split into two streams in the housing 43 as indicated by arrows Ai and A2.

The forward end of the air supply assembly 40 comprises a nozzle 45 for controlling the airflow characteristics through the 42 of the vent Specifically, the nozzle 45 defines a flow path whereby the first 46 and second 47 flow channels converge at (or proximal to) the vent 42. The body 43 and/or a forward portion 62 of the flow divider 60 are profiled to control the flow through the nozzle 45 and ensure that respective air flows At and A2 from the first 46 and second 47 flow channels converge and flows out of the slot of the vent 42 as a substantially sheet like or laminar airflow (as indicated by arrow A). In the embodiment of Figure 5, the forward portion 62 of the divider 60 is provided with a bulbous member to provide a flow guidance surface through the nozzle section 45 if the air supply assembly. It will, however, be appreciated that in other embodiments the divider may have a simple planar profile and the same effect of guiding the flow through the nozzle may be achieved by suitably shaping or profiling the adjacent surfaces of the body 43.

In use, the relative angle of the valve element 52 of valve 50 is adjusted so that the proportion of incoming airflow F entering the upper or lower flow channels 46 and 47 can be adjusted. This results in an adjustment of the volume of the relative flows AI and A2 and, as a result, the relative momentum of the two flows Ai and A2 at the nozzle 45 is determined by the position of the valve 50. The variation of the net momentum of the nozzle flow 45 enables adjustment of the the direction of the outward flow A from the vent 42. Such an arrangement requires no movable vanes at the vent outlet and can be more efficient than conventional vanes which present greater restriction to airflow.

Further, control of the valve 50 may be remote from the vent 42 so may be more easily controlled by electronic controller than vane-controlled arrangements.

To ensure that a smooth airflow is provided along the entire width of the curving vent 42, the flow conditions along the length of the vent should remain consistent. This may be achieved by ensuring that the position of the forward end 62 of the flow divider conform to the curvature of the vent 42. This is schematically represented in Figure 7 where it may be noted that the forward end 62 of the divider has a curvature along its length which matches the curvature of the vent 42. As such, the spacing between the vent 42 and the divider 60 may remain substantially constant. The cross section of the nozzle 45 formed between the housing 43, forward end 62 of the divider and slot 60 may for example be substantially identical in dimensions/proportions at any longitudinal point along the air supply assembly (with only the relative position of the nozzle with relation to the vehicle and/or ventilations system components being varied). The provision of a constant spacing may avoid undesirable turbulence along the length of the slot which could otherwise increase acoustic noise or pressure loss through the vent.

The length of the divider 60 may vary along the width of the assembly to accommodate the positioning of the forward portion 62. As such, the rearward edge 61 of the divider may be linear and extend directly parallel to the valve 50.

It may be noted from Figures 5 and 7 that a gap G may be provided between the valve element 52 and the rear end 61 of the divider 60. The gap is maintained throughout the range of motion of the valve element 51. The provision of a gap G may be contrasted with the conventional approach of seeking to seal, or substantially seal (for example allowing for a tolerance gap of less than lmm), the valve element 52 so that all the flow passes via the valve element. The gap G allows a small but steady bleed of air to pass around the valve. The applicants have found that such an airflow may ensure that there is no valve position in which the gap becomes sufficiently small for acoustic noise such as whistling to be caused.

An alternate embodiment is shown in figure 6. In this embodiment the element 52' of the valve 50' is formed as a cam shaped body in the flow path F'. The valve element 52' is rotatable about an off-centre axis 53' such that it can move between positions in which it is obstructing either one, or neither, of the first 46' and second 47' flow channels. The divider 60' of this embodiment is formed as an enlarged body in comparison with the previous embodiment such that the forward end 62' converges but does not include a bulbous member. The basic operate principle of this embodiment is identical to that of the earlier embodiment and again the forward end 62' of the divider 60' and the walls 43' of the air supply assembly form a nozzle 45'such that the streams from the flow channels 46' and 47' converge.

Although the invention has been described above with reference to embodiments, it will be appreciated that various changes or modification may be made without departing from the scope of the invention as defined in the appended claims. For example, whilst the embodiments show an air supply assembly having a horizontal (or transverse) orientation with the slot shaped vent extending longditudinally along a dashboard, other arrangements may be used depending upon the configuration of the vehicle. For example, a vent having a generally vertically extending slot could be positioned along a pillar of a vehicle. Likewise, whilst the embodiments curve in an axis which is forward or backward relative to the slot, the same principles of maintaining a consistent spacing between the divider and slot could apply to a slot which curves perpendicular to its length (for example a horizontal slot with an upward/downward vertical curvature).

Claims

Claims 1. A vehicle comprising a passenger cabin and a ventilation system for ventilating the passenger cabin, the ventilation system comprising a vent for discharging air into the passenger cabin, wherein the vent comprises: a housing having an inlet, an outlet, and a chamber communicating the inlet with the outlet, a flow divider located in the chamber dividing the chamber into a first passage and a second passage, the flow divider having a trailing edge upstream of the outlet extending the length of the outlet, the first and second passages converging at the trailing edge of the flow divider, a valve located upstream of the flow divider for apportioning airflow between the first and second passages, wherein the valve is movable relative to the flow divider through a range of movement for adjusting the apportionment of airflow between the first and second passages, and the valve and the flow divider are separated by a gap of at least 2 millimetre throughout the range of movement of the valve.
2. A vehicle as claimed in any one of the preceding claims, wherein the gap is constant throughout the range of movement of the valve.
3. A vehicle as claimed in any one of the preceding claims, wherein the gap is constant across the span of the valve.
4 A vehicle as claimed in any one of the preceding claims, wherein the flow divider has a leading edge, the valve is located adjacent a section of the leading edge, and the section of the leading edge is straight.
5. A vehicle as claimed in claim 4, wherein the valve is mounted for rotation about an axis, and the axis is parallel to the straight section of the leading edge.
6 A vehicle as claimed in any one of the preceding claims, wherein the gap is at least 3 millimetre.
7. A vehicle as claimed in any one of the preceding claims, wherein the gap is at least 4 millimetre.
8. A vehicle as claimed in any one of the preceding claims, wherein at a closest position of the valve to the flow divider the gap is no greater than 10 millimetre.
9. A vehicle as claimed in any one of the preceding claims, wherein at a closest position of the valve to the flow divider the gap is no greater than 5 millimetre.A vehicle as claimed in any one of the preceding claims, further comprising a blower for supplying an airflow to the vent