GB2577556A

GB2577556A - Vehicle air conditioning

Info

Publication number: GB2577556A
Application number: GB1815866.7A
Authority: GB
Inventors: James Woodfield Daniel; Patrick Ferreira Ross; James Peters Laurent
Original assignee: Dyson Automotive Research and Development Ltd
Current assignee: Dyson Automotive Research and Development Ltd
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2020-04-01
Also published as: WO2020065285A1

Abstract

A vehicle has a passenger cabin, a door to the passenger cabin and an air conditioning system 108. The air conditioning system includes a Peltier device 301, a blower 302 for directing an airflow over a side of the Peltier device, and a duct 401 for ducting air to an inlet 802 of the blower. The blower is mounted to the door, and an inlet of the blower faces towards the passenger cabin. The ducting inlet may be located on the underside of the door, and in the footwell of the passenger cabin. The Peltier device might have a further side with a further blower 303 for directing a further air flow over the further side of the Peltier device.

Description

VEHICLE AIR CONDITIONING

Field of the Invention

The present invention relates to a vehicle with an air conditioning system for heating or cooling air supplied to the cabin of the vehicle.

Background of the Invention

Vehicles, such as passenger cars, often include an air conditioning system for heating, cooling or dehumidifying air supplied to the passenger cabin. Such systems typically comprise a heating element, a cooling element, and a motor driven fan to blow air over the heating/cooling elements into the passenger cabin. It is desirable to improve the performance and the noise-vibration-harshness (NVH) characteristics of vehicle air conditioning systems in order to improve cabin occupant comfort. For example, it is desirable to reduce the transmission of audible noise, heat energy, or vibrations from the air conditioning system to the passenger cabin. Furthermore, it is desirable to improve the energy efficiency of vehicle air conditioning systems to minimise the energy consumed by the system. Reducing the energy consumption of vehicle air conditioning systems is particularly important for battery electric vehicles (BEVs) to maximise the driving range of the vehicle.

Summary of the Invention

The present invention provides a vehicle comprising a passenger cabin, a door to the passenger cabin, and an air conditioning system comprising, a Peltier device, a blower for directing an airflow over a side of the Peltier device, and ducting for ducting air to an inlet of the blower, wherein the blower is mounted within the door with the inlet facing the passenger cabin.

In this specification the word 'blower' is intended to define a device capable of moving air. For example, each of the one or more blowers may comprise a movable component 30 capable of moving air, for example, a bladed rotor such as an impeller, and a device for supplying motive force to the moving component, for example, a motor such as an electric motor for driving the rotor to rotate.

The Peltier device is operable as a heat pump to transfer heat energy between first and second sides of the Peltier device. The airflow may thus be heated or cooled by the Peltier device as it is directed by the blower over the side of the Peltier device. The airflow could be supplied to the passenger cabin to thereby heat or cool the passenger cabin. As an alternative, the Peltier device could be used as a radiative heater, in which the passenger cabin is heated or cooled by radiative heat transfer between air in the passenger cabin and a further side of the Peltier device, in which event the airflow could be discharged to outside the passenger cabin to carry away waste heat from the side of the Peltier device.

The inlet of the blower faces towards the passenger cabin. In other words, the blower is mounted with an opening through which an influent airflow enters the blower oriented inwardly of the vehicle towards the passenger cabin. In this arrangement at least a portion of the ducting which ducts air to the inlet of the blower is located between the blower inlet and the passenger cabin. This has the advantage that the ducting may attenuate audible noise emanating from the inlet of the blower. As a result transmission of noise from the blower to the passenger cabin is reduced. Furthermore, because, considered conversely, the blower is arranged between an exterior of the vehicle and at least a portion of the ducting, the portion of the ducting may tend to be thermally insulated from the exterior of the vehicle by the blower. As a result thermal exchange between air flowing through the ducting and the external environment of the vehicle may be reduced.

The air conditioning system may discharge the airflow to the passenger cabin. In other words, after having passed over the side of the Peltier device, the airflow may be admitted to inside the passenger cabin. In this arrangement the airflow may thus be used to heat or cool the passenger cabin.

The door may comprise an armrest. That is to say, the door may define a ledge projecting towards the passenger cabin, for example, a generally horizontal ledge, which may serve as a rest for an arm of a cabin occupant. The armrest may he defined by a wall of the door bounding the passenger cabin. Provision of the armrest may improve passenger comfort.

The blower may be mounted behind the armrest. In other words, the blower may be mounted on a side of the armrest opposite the passenger cabin at approximately the same height as the armrest; that is to say, the blower and the armrest may he intersected by the same horizontal plane. An axis of rotation of the blower may thus extend through the armrest. Where the armrest is defined by a wall of the door bounding the passenger cabin, the blower may be located on a side of the wall opposite the passenger cabin.

Thus, in this arrangement the armrest is located between the blower and the passenger cabin. An advantage of this arrangement is that the volume of the armrest may act to further attenuate noise from the blower, and particularly from the inlet of the blower, and thereby reduce its transmission to the passenger cabin. As a result transmission of noise from the blower to the passenger cabin may be further reduced.

The ducting may project into a recess defined by the armrest. That is to say, the ducting supplying air to the inlet of the blower may be at least partly located in a recess of the armrest. For example, the door may comprise a compartment, the blower may be mounted within the compartment, the compartment may comprise a recess defined by the armrest, and the ducting may project into the recess. That is to say, the armrest may be at least partly hollow to define a recess within its volume, and the recess may form an enlargement to the volume of the compartment of the door. Thus, in this arrangement the ducting may he at least partially located in a recess defined by the armrest. Thus, by utilising the volume of the armrest, this arrangement allows the ducting to project inwardly of the plane of the door towards the passenger cabin without intruding on the passenger cabin. This arrangement is generally advantageous because, as the ducting is at least partially accommodated within the recess of the armrest, the depth of the door occupied by the blower and ducting may be reduced. A particular advantage arises where the blower is located behind the armrest, that is to say, where the blower is mounted to the door at approximately the same height as the armrest such that the inlet of the blower is aligned with the recess of the armrest. In this arrangement the ducting may utilise the volume of the recess to join to the inlet of the blower. This is particularly advantageous where the ducting is required to turn the airflow for admission to the blower inlet, for example, to turn the airflow from a radial direction (relative to the blower) to an axial direction (relative to the blower), as the radius of curvature of the bend in the ducting may he increased by allowing the ducting to project into the recess.

Increasing the radius of curvature of the bend in the ducting results in a more gradual turning of the air, and so reduces the restriction presented by the bend to the airflow flowing through the duct.

The blower may draw air through the ducting from inside the passenger cabin. That is to say, the blower may draw the airflow from inside the passenger cabin. Drawing the airflow from within the passenger cabin is advantageous because air within the passenger cabin may be cleaner and/or less humid than air outside the passenger cabin, for example, atmospheric air in the environment surrounding the vehicle. This may be the case particularly where influent airflow to the passenger cabin is filtered before admission to the passenger cabin. Consequently the components of the air conditioning system, for example, the Peltier device and/or the blower are less susceptible to damage resulting from exposure to the air. Further, air within the passenger cabin is likely to be less turbulent than air outside the passenger cabin. A turbulent influent airflow to the air conditioning system could result in buffeting of the airflow, which could tend to damage the blower and/or result in blower 'chatter' producing audible noise. Thus, drawing the airflow from inside the passenger cabin may reduce the level of audible noise generated by the blower and protect the blower and the Peltier device from damage.

Further, where the airflow is supplied to the passenger cabin of the vehicle. drawing the airflow from inside the passenger cabin is advantageous because, in certain operating conditions, the air within the passenger cabin may be closer n temperature to the desired cabin air temperature than air outside the passenger cabin. For example, in a hot climate where the air conditioning system is used for cooling the cabin, the air within the passenger cabin may be cooler than air outside the passenger cabin. Thus, drawing the airflow from the passenger cabin reduces the amount of work that the Peltier device is required to do on the first airflow to maintain a desired cabin air temperature.

Consequently the energy efficiency of the air conditioning system may be improved.

Further, the temperature of air inside the passenger cabin is likely to he more stable than that of air outside the passenger cabin. Unstable influent air temperatures may complicate control of the temperature of the Peltier device and so of the temperature of the airflow discharged to the passenger cabin. Conversely, drawing the airflow from inside the passenger cabin may simplify temperature control of the air conditioning system. Further, air within the passenger cabin may he cleaner and/or less humid than atmospheric air. This may be the case particularly where influent airflow to the passenger cabin is filtered before admission to the passenger cabin. Consequently the components of the air conditioning system, for example, the Peltier device and/or the blower are less susceptible to damage resulting from exposure to the air. Further, air within the passenger cabin is likely to be less turbulent than atmopsheric air outside the passenger cabin. A turbulent influent airflow to the air conditioning system could result in buffeting of the airflow, which could tend to damage the blower and/or result in blower 'chatter' producing audible noise. Thus, drawing either or both of the first and second airflows from inside the passenger cabin may reduce the level of audible noise generated by the blower and protect the blower from damage.

An inlet of the ducting may be located on an underside of the door. In other words, the inlet may be located on a ground-facing wall of the door. Audible noise generated by the blower may tend to travel along the duct and be emitted from the inlet of the ducting. Locating the inlet on an underside of the door has the advantage that noise emitted from the inlet will tend to be directed downwardly towards a ground surface, and so will tend to he attenuated. Attenuation of noise from the inlet of the ducting is particularly important where the inlet is open to the passenger cabin. Thus, the arrangement may reduce perception of noise from the blower by cabin occupants.

Further, locating the inlet on the door underside has the advantage that debris and particulates will be less likely to become entrained in the influent airflow and thus the level of contaminants in the influent airflow may he reduced. As a result the airflow through the air conditioning system may be cleaner, which may reduce damage to the Peltier device and the blower. Further, the inlet may be aesthetically unsightly, and locating the inlet on the underside of the door may mean that the inlet is hidden from the normal view of a passenger cabin occupant. Further, locating the inlet on the underside of the door has the advantage that liquids, for example, water condensate, incident on vertical sides of the door will be less likely to run down the sides and inwardly through the inlet into the air conditioning system.

An inlet of the ducting may be located in a footwell of the passenger cabin. As noted above, audible noise generated by the blower may tend to travel along the duct and be emitted from the inlet of the ducting. Locating the inlet in a footwell region of the passenger cabin has the advantage that the noise is emitted to the footwell of the passenger cabin, and will tend to he attenuated when travelling through the air of the passenger cabin to an occupant's ears. Thus, the occupant may perceive a lower level of noise.

Further, air in a footwell region of the passenger cabin may tend to be cooler than air in higher regions of the passenger cabin. As previously noted, providing the air conditioning system with relatively cool air may, in certain operating conditions, improve the performance and/or the energy efficiency of the air conditioning system. Furthermore, by drawing the airflows from a footwell of the passenger cabin, a passenger cabin occupant will be less likely to perceive the influent airflows than if the airflows were drawn from a higher region of the cabin. Consequently the perceived refinement of the air conditioning system is improved.

The Peltier device may be mounted to the door. For example, the Peltier device may be mounted within the door. This arrangement has the general advantage that the distance the airflow must he ducted between the blower and the Peltier device may he reduced. Consequently, ducting carrying the airflow therebetween may be shortened, thus reducing the mass and complexity of the ducting and the restriction to the airflow passing along the ducting. Further, where the blower is mounted to the door, mounting the Peltier device also to the door has the specific advantage that airflow between the blower and the Peltier device is not interrupted when the door is opened.

The blower may draw air in through the inlet in an axial direction and expel air in a radial direction. In other words, the blower may be a centrifugal fan. In this arrangement, ducting supplying air to the inlet of the blower may extend axially towards the blower, and ducting carrying air from an outlet of the blower may extend radially from the blower. This arrangement thus permits a relatively compact construction of the blower and ducting.

The air conditioning system may discharge the airflow to the passenger cabin through an outlet located on the door. It may be advantageous to locate the outlet for the airflow on the door such that the outlet is located in close proximity to a seated occupant Locating the outlet close to the occupant may allow more effective and/or efficient heating or cooling of the cabin occupant than where the outlet is more distant to the occupant. Furthermore, locating the outlet on the door may advantageously allow airflow from the outlet to be directed towards each region of a seated occupant's body, for example, the feet or head areas. Moreover, locating the outlet on the door may be particularly advantageous where either of the Peltier device and/or the one or more blowers is mounted to the door, as the length. and so mass, and complexity of ducting for ducting the first airflow between the Peltier device and/or blowers may be reduced. In particular, locating the outlet on the door avoids the need to duct the airflow from the Peltier device and/or the blowers to the relatively movable door. This simplifies the ducting, and further has the result that the first airflow between the outlet and the Peltier device and/or the blowers is uninterrupted when the door is opened.

The Peltier device may be located downstream of the blower. In this arrangement the blower thus pushes air over the side of the Peltier device. The energy consumed by the blower pushing air over the Peltier device may he relatively lesser than the energy consumed for the blower to draw the airflow over the side of the Peltier device.

Consequently, this arrangement may reduce the energy consumption of the air conditioning system.

The Peltier device may comprise a further side, and the Peltier device may be mounted to the door with the side facing towards the passenger cabin and the further side facing away from the passenger cabin. In this arrangement the major dimensions of the Peltier device, that is the length and width dimensions, extend generally in the same plane as the door. Consequently, the extent to which the Peltier device protrudes from the plane of the door is reduced. As a result, the area of each of the first and second sides of the device may he relatively large without intruding on the passenger cabin. Increasing the areas of the first and second sides of the Peltier device may advantageously improve thermal transfer between the Peltier device and the incident airflows. Further, this orientation may simplify ducting of the airflow to the passenger cabin.

The air conditioning system may comprise a further blower for directing a further airflow over a further side of the Peltier device. Consequently, the second side of the Peltier device may be provided with a flow of air by the second blower. The second side of the Peltier device may thus be able to absorb or reject a greater quantity of heat energy to the airflow than would be possible to a static body of air.

The reference in this specification to a blower and a further blower is to first and second devices that are independently operable. That is to say, to blowers which have a construction that permits each blower to he operated independently of the other blower. For example, each of the blowers may comprise a rotor capable of moving air and an electric motor for driving the rotor to rotate. This is compared, for example, to a blower comprising multiple rotors rigidly mounted to a shaft of a common motor, where the operation of the two rotors are linked.

Employing first and second blowers to generate the first and second airflows has the first advantage that the rate of flow of the first and second airflows may be set differently. This is advantageous where it is desirable for the rate of flow of the first airflow to be greater or lesser than the rate of flow of the second airflow. For example, where the air conditioning system is being used to cool the passenger cabin, a relatively high rate of airflow over the second side of the Peltier device may he required in order to remove the required amount of heat energy. This may be the case particularly in a warm climate, where the capacity of the second airflow for absorbing heat energy may be relatively low. It may be desirable however that the first airflow is set to a relatively lower rate, firstly to increase the dwell time of the first airflow with the first side of the Peltier device and so improve thermal transfer therebetween, and secondly to reduce perception of the airflow by cabin occupants, thereby improving occupant comfort.

Further, using first and second blowers that are independently operable allows the rate of flow of the first airflow to be varied independently of the rate of the flow of the second airflow. As a result, the rate of flow of either of the first and second airflows may be varied without also changing the flowrate of the other airflow. This may be advantageous where it is desirable to increase or decrease one of the first and second airflows whilst maintaining the rate of flow of the other airflow constant.

Further, the first and second blowers allow a given total volumetric flow rate over the first and second sides of the Peltier device to be achieved using two relatively small blowers instead of a single larger blower. Smaller blowers may advantageously be easier to 'package' within a vehicle.

The further airflow may be discharged to outside the passenger cabin. This arrangement has the advantage that heat energy absorbed from the second side of the Peltier device is removed from the passenger cabin. As a result, net heating or cooling of the passenger cabin may be achieved.

Brief Description of the Drawings

In order that the present invention may he more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figures 1 and 2 are illustrative views of a vehicle comprising an air conditioning system embodying the invention; Figure 3 is a perspective view of the air conditioning system; Figure 4 is an exploded perspective view of the air conditioning system; Figures 5a, 5b and 5c are front, side and rear elevation views respectively of the air conditioning system; Figure 6 is an exploded perspective view of a Peltier device of the air conditioning system; Figure 7 is an illustrative view of a section through the Peltier device along the line A-A depicted hi Figure 6; Figures 8a and 8b are front and side elevation views respectively of a blower of the air conditioning system; Figure 9 is a schematic representation of a controller for controlling the operation of the air conditioning system; and Figure 10 is an illustrative view of a section through a door of the vehicle showing the air conditioning system mounted within the door.

Detailed Description of the Invention

Referring firstly to Figures 1 and 2, a vehicle, which in the example takes the form of a passenger car 101, comprises a body structure 102 defining a passenger cabin 103 for accommodating passengers, door openings in the side of the body structure 102 to permit passenger ingress and egress from the cabin 103, and a plurality of doors 104, 105, 106, 107, hingedly connected to the body structure 102 adjacent a respective door opening to selectively close the door opening.

The car 101 further comprises a plurality of air conditioning systems, 108, 109, 110, 111, for heating or cooling air supplied to the passenger cabin 103. Each of the air conditioning systems 108 to 111 is mounted to a respective door 104 to 107 and includes an inlet and an outlet open to the passenger cabin 103. In the way that will be described further with reference to Figure 10, each of the air conditioning systems 108 to 111 is operable to draw air from the passenger cabin 103, selectively heat or cool the air, and discharge the heated or cooled airflow back to the passenger cabin to thereby heat or cool the cabin environment.

Each air conditioning system 108 to 111 is substantially identical, as is the mounting of each air conditioning system to a respective door. For brevity therefore only air conditioning system 108 and door 104 will be described in detail herein, on the understanding that the same teachings are applicable to air conditioning systems 109 to 111 and doors 105 to 107.

Referring next to Figures 3 to 9, the air conditioning system 108 comprises principally a Peltier device 301, first and second blowers 302, 303, three stages of ducting, indicated generally at 304, 305, and 306, and an electronic controller 901 for controlling the operation of the Peltier device 301 and the blowers 302, 303.

The Peltier device 301 is arranged within a housing comprising front and rear parts 601, 602 enclosing first and second sides respectively of the Peltier device 301.

The Peltier device 301 comprises an array 701 of n-type and p-type semiconductors, electrically conductive copper plates 702, thermally conductive and electrically insulating ceramic plates 703, 704, and finned aluminium heatsinks 705, 706. The semiconductors are arranged in a square array 701 of n-and p-type semiconductor pairs which are electrically coupled in series by the copper plates 702. The semiconductor array 701 is sandwiched between the ceramic plates 703, 704, which have their inner surfaces thermally coupled to opposing ends of the semiconductors in the array, and which thereby define first and second sides 707, 708 respectively of the Peltier device 301. Finned aluminium heat sinks 705, 706 are provided in thermal contact with the outer surfaces of the ceramic plates 704, 705 respectively.

The front and rear parts 601, 602 of the housing form ducts for guiding airflows over the first and second sides 707, 708 respectively of the Peltier device 301. Thus, the front part 601 defines with the ceramic plate 703 a first duct over the first side 707 of the Peltier device 301, and the rear part 602 defines, with the ceramic plate 704 a second duct over the second side 708 of the Peltier device 301. As shown best in Figure 7, the aluminium heat sinks 705, 706 are arranged with their fins extending longitudinally the height of the Peltier device and laterally across each duct. Thus, the fins of each heatsink 705, 706 define a plurality of narrow longitudinally extending channels through each duct. Airflows through each duct flow through the narrow channels in contact with the fins of the heatsink, thus ensuring good thermal transfer between the airflows and the first and second sides 707, 708 of the Peltier device 301 respectively.

When a direct current is applied across the semiconductor pairs, electrons flowing between the dissimilar materials transition between energy states, absorbing or releasing thermal energy at the junction in dependence on the direction of current flow. Electrons moving in a direction from the n-type material to the p-type material, jump to a higher energy state and absorb thermal energy at the junction from the ceramic plate 703, thereby cooling the ceramic plate 703. As the electrons move from the p-type material to the n-type material of an adjacent pair, the electrons revert to a lower energy state, releasing thermal energy to, and so heating, the ceramic plate 704. Thus, in this mode of operation the Peltier device may be used to cool a first airflow flowing over the first side 707 of the Peltier device by rejecting heat to a second airflow flowing over the second side 708. Conversely, when the polarity of the electric current is reversed, electrons flowing in a direction from the p-type material to the n-type material reject heat to the ceramic plate 703 and absorb heat from the ceramic plate 704. In this mode of operation the Peltier device may thus be used to heat the first airflow passing over the first side 707 by absorbing thermal energy from the second airflow flowing over the second side 708 of the Peltier device.

Referring particularly to Figures 8a and 8b, the blowers 302, 303 are substantially identical, and generally conventional, in construction. Each blower is a centrifugal squirrel-cage' type blower, comprising a housing 801 having an inlet 802 and an outlet 803, an electric motor 804, and an impeller 805 mounted on a shaft of the motor for rotation within the housing 801 about an axis of rotation 806. Rotation of the impeller 805 about the axis 806 draws an airflow into the housing 810 through the inlet 802 in an axial direction, i.e. a direction parallel to the axis of rotation 806 of the impeller 805. The airflow is accelerated centrifugally by the turn of the impeller 805, and then discharged from the housing 801 in a radial direction along the axis 807 extending radially relative to the axis of rotation 806, through the outlet 801 The first stage of ducting 304 comprises first and second ducts 401, 402 for ducting first and second airflows to the first and second blowers 302, 303 respectively. Each of the ducts 401, 402 comprises an inlet 410, 411 at one end and an outlet 412, 413 at the other end. A particle filter assembly 409 is arranged over the inlets 410, 411 to filter air drawn into the ducts. The ducts 401, 402 are substantially identical in form and each comprise a long first section 414, 415 leading from the inlet 410, 411, and a relatively shorter second section 416, 417 leading from the first section 414, 415 to the outlet 412, 413. The second section 416, 417 extends generally orthogonally relative to the first section 414, 415 thus forming a bend 418, 419 where the axis of the duct turns. In the illustrated assembled state the first section 414, 415 of each duct 401, 402 extends in a generally radial direction relative to the axis of rotation 806 of the blowers 302, 303, between the inlet 410, 411 of each duct and the second section 416, 417, and the second section 416, 417 extends in a generally axial direction relative to the axis of rotation 806, from the first section 414, 415 to the outlet 412, 413. Air flowing through each of the ducts 401, 402 thus undergoes a turn through the bend 418, 419 from the generally radial direction to the generally axial direction. The outlet 412 of the first duct 401 is joined to the inlet 802 of the first blower 302, and the outlet 413 of the second duct 402 is joined to the inlet 802 of the second blower 303.

The second stage of ducting 305 comprises third and fourth ducts 403, 404 for ducting airflows between the blowers 302, 303 and the Peltier device 30L The third duct 403 is arranged for ducting a first airflow from the outlet 803 of the first blower 302 to the first side 707 of the Peltier device, and comprises an inlet 420 mated to the outlet 803 of the first blower 302 and an outlet 421 mated to the first part 601 of the housing. The third duct 403 is generally straight and defines a generally linear passage extending between the inlet 420 and the outlet 421. The fourth duct 404 is arranged for ducting a second airflow from the second blower 303 to the second side 708 of the Peltier device 301, and comprises an inlet 422 mated to the outlet 803 of the second blower 303 and an outlet 423 mated to the second part 602 of the housing. The fourth duct 404 is generally S' shaped, and defines a convoluted passage between the inlet 422 and the outlet 421 Referring particularly to the side view of Figure 5b, In the assembled state the first and second blowers 302, 303 are arranged in substantially the same plane with their inlet axes 806 and outlet axes 807 extending perpendicular and parallel to the plane respectively. The first blower 302 is mounted in approximate lateral alignment with a longitudinal centreline of the Peltier device 301 such that the outlet axis 807 of the first blower 302 projects across the Peltier device 301 over the first side 707. In this arrangement a first airflow from the first blower 302 may ducted by the third duct 403 along a generally linear path from the blower 302 to the first side 707 of the Peltier device 301. The second blower 302 is arranged with the axis 807 laterally offset from the Peltier device 301. The fourth duct 404 is arranged to duct an airflow from the outlet 803 of the second blower 303 to the second side 708 of the Peltier device 301 behind the third duct 403.

The third stage of ducting 306 comprises fifth and sixth ducts 405, 406 for ducting the first and second airflows from the first and second sides 707. 708 of the Peltier device 301 to first and second outlets of the air conditioning system. The fifth duct 405 is arranged for ducting the first airflow from the first side 707 of the Peltier device 301. An inlet 424 of the fifth duct 405 is joined to the first part 601 of the housing of the Peltier device 301 for receiving a first airflow passed over the first side 707 of the Peltier device 301. A vent assembly 407 comprising an outlet opening 428 is coupled to an outlet 425 of the fifth duct 405 for selectively shaping and throttling the first airflow. An inlet 426 of the sixth duct 406 is joined to the second part 602 of the housing of the Peltier device 301 for receiving a second airflow passed over the second side 708 of the Peltier device 301. An outlet 427 of the sixth duct 406 is fitted with a valve assembly 408 for opening and closing the duct 406.

Referring again in particular to Figure 5b, the valve assembly 408 is operable to open and close the outlet 427 of the sixth duct 406 to control the flow of air through the duct 406. In the example, the valve is configured as a one-way valve to open when acted on by the second airflow flowing through the duct 406 in a direction from the inlet 426 to the outlet 427, and to actuate automatically to a closed condition when not acted on the by the second airflow through the duct, to thereby inhibit reverse airflow through the duct 406. The valve assembly comprises a hingedly carried valve flap 501 that is rotatable between the open and closed positions shown in the Figure about the axis of rotation 502. In the open position the valve flap 501 extends generally parallel to the axis 503 of the sixth duct 406 at the outlet, thereby presenting a minimal restriction to an airflow along the duct. In the closed position the valve flap 501 depends downwardly from the axis 501 generally orthogonally to the duet axis 501 thereby occluding the outlet 427 of the duet 406 to inhibit airflow through the duct.

As shown in the Figure, the axis 502 about which the flap 501 rotates is arranged to extend at a height higher than the centre of gravity 504 of the flap in the closed position. Consequently the flap 501 is biased to the closed, downwardly depending, position by the force of gravity acting on the flap In the example, the flap 501 is adapted to have a relatively low mass. This has the advantage that only a relatively low force is required to be exerted on the flap to move the flap from the closed position to the open position. As a result the valve flap will tend to be moved from the closed position to the open position, against the biasing force of gravity acting on the flap, automatically when acted on by the second airflow without presenting an excessive restriction to the second airflow along the duct Conversely, when the second airflow through the duct is ceased, or indeed if reverse flow conditions were to develop, the valve flap 501 will tend to default under the force of gravity to the closed position, thereby preventing backflow through the duct 406.

Alternatively or additionally, the valve assembly 408 could be provided with a separate biasing member, for example, a spring, connected between the flap 501 and the duct 406 for biasing the flap to the closed position. In such an alternative configuration it may be advantageous for the spring to exert only a relatively low restorative force on the valve flap, such that only a relatively low force is required to he exerted on the flap by the second airflow to actuate the flap to the open position. As a further exemplary alternative, the valve assembly 408 could be provided with a controllable motor for actuating the flap between the open and closed positions. A motor controlled flap may advantageously allow more precise control of the state of the valve, however may disadvantageously increase the complexity of the construction and operation of the valve.

Referring next particularly to Figure 9, the air conditioning system 108 comprises an electronic controller 901 for controlling the operation of the first and second blowers 303, 303 and of the Peltier device 301. In the example, the electronic controller 108 comprises an electronic control unit (ECU) 902, first and second electronic speed controllers (ESC) 903, 904, and first and second temperature sensors 905, 906.

The ECU 902 comprises a number of inputs and outputs, including input/output 906 for interfacing with other electronic circuitry of the vehicle, for example, with a HMI (human-machine interface) of the vehicle. Each of the electronic speed controllers 903, 904, the Peltier device 301, and the temperature sensors 905, 906 are connected to and under the common control of the ECU 902. The ECU 902 is functional to control independently the first and second ESCs 903, 904, and to control the magnitude and polarity of an electric current supplied to the Peltier device 301.

The first and second ESCs 903, 904 are connected to the motors 804 of the first and second blowers 302, 303 respectively, and are functional to control electric currents supplied to each motor independently. Through control of the ESCs 903, 904 the ECU 902 is thus operable to control independently the blower speeds of each of the first and second blowers 302, 303 respectively.

In the example each of the temperature sensors 905, 906 are negative temperature coefficient thermistors which, as is known, have electrical resistance characteristics which increase proportionally as a function of the temperature of the device. The ECU 902 supplies an electrical current to each of the thermistors 905, 906 and by measuring the resistance of the thermistor may deduce the temperature of each device. The first thermistor 905 is arranged within the passenger cabin 103 of the vehicle exposed to air inside the passenger cabin. The second thermistor 906 is arranged on an exterior surface of the vehicle exposed to atmospheric air surrounding the vehicle. Thus, through the thermistors 905, 906 the ECU 902 may detect the temperature of air inside the passenger cabin 103 and of atmospheric air surrounding the vehicle.

In operation, the ECU 902 may receive a signal from an HMI interface indicating a desired passenger cabin air temperature. The ECU 902 is functional to detect the actual temperature of air inside the passenger cabin via the temperature sensor 905, and of air outside the passenger cabin via the temperature sensor 906, and to control the operation of the Peltier device 301 and the blowers 302, 303 in dependence on the measured temperatures. Thus, the controller 902 may control the power and polarity of the current supplied to the Peltier device 301 to control the temperature of the first side 709 of the Peltier device 301. Via the ESCs 903, 904, the controller may also control independently the speeds of each of the blowers 302, 303 to control the rate of flow of the first and second airflows over the first and second sides 708, 708 of the Peltier device 301.

Referring finally to Figure 10, the door 102 is shown in the closed position in which the door 102 is received in the door opening 1001 thereby closing the door opening.

The door opening 1001 is defined between roof and floor structures 1002, 1003 of the body structure 102 of the vehicle. In the illustrated closed position, an upper edge of the door is received in a frame 1004 mounted to the roof structure 1002. The floor structure 1003 defines a sill 1005 extending along a lower extent of the door opening 1001, and comprises an upwardly projecting seal 1006 extending along an upper surface of the sill 1005. In the closed position a lower surface of the door overlies the upper surface of the sill 1005 and is seal ingly engaged by the seal 1005 forming a substantially airtight seal between the sill 1005 and the door 102, thereby sealing the passenger cabin 103 from atmospheric air surrounding the vehicle.

The door 102 comprises an outer wall 1007 forming an exterior surface of the vehicle, an inner wall 1008 forming an interior surface of the vehicle bounding the passenger cabin 103, and a partition wall 1009 located between the outer wall 1007 and the inner wall 1008. The door 102 further comprises a slidably carried window pane 1010 which is movable between open and closed positions. The partition wall 1009 divides the internal volume of the door in two. A first compartment 1011 is defined between the outer wall 1007 and the partition wall 1009. and a second compartment 1012 is defined between the partition wall 1009 and the inner wall 1008. The partition wall 1009 seals the second compartment 1012 from the first compartment 1011 to substantially prevent leakage of air from the first compartment 1011 to the second compartment 1012.

The first compartment 1011 of the door forms a well for receiving the window pane 1010 and comprises an opening 1013 at an upper end through which the window pane may he lowered and raised in and out of the compartment 1011, representing open and closed positions of the window pane respectively. Seal parts 1014, 1015 are arranged along edges of the opening 1013 to sealingly engage outer and inner surfaces respectively of the window pane 1010 to inhibit ingress of liquids, for example, rain water, into the compartment 1011 through the opening 1013. The first compartment 1011 comprises a vent aperture 1016 through a wall at a lowermost extent of the compartment. The first compartment 1011 may thus exchange air with atmosphere through the vent aperture 1016. Furthermore, the vent aperture 1016 permits draining of liquids, for example, rainwater, from within the first compartment to outside the vehicle.

The air conditioning system 108 is installed within the second compartment 1012-Consequently the air conditioning system 108 is sealed from the environment of the first compartment 1011 by the partition wall 1009. As a result the air conditioning system 108 is less susceptible to damage from exposure to air or liquids within the first compartment 1011. Furthermore, when located in the second compartment 1012, the air conditioning system 108 is thermally insulated from the external environment of the vehicle by the body of air within the first compartment 1011, which protects the air conditioning system from damage that might result from exposure to extremes of atmospheric temperature outside the vehicle. The air conditioning system 108 is mounted to the partition wall 1009 by a plurality of 'soft' fixings, such as rubber bobbin 1017. Soft mounting the air conditioning system to the partition wall 1009 advantageously reduces transmission of vibrations therebetween. This may advantageously reduce noise resulting from transmission of vibrations generated by the air conditioning system to the door 102, and conversely may reduce damage to sensitive components of the air conditioning system, for example, the blowers 302, 303, resulting from transmission of vibrations from the door 102 to the air conditioning system 108.

The inner wall 1008 of the door defines an armrest 1017, forming a ledge 1018 projecting generally horizontally towards the passenger cabin 103, thus serving as a rest for an ann of a cabin occupant. As shown in the Figure, the armrest 1017 is generally hollow such that a recess 1019 is defined within the volume of the armrest forming an enlargement to the second compartment 1012. The air conditioning system is mounted to the door with each of the first and second blowers located behind the armrest 1017 of the inner wall 1008, that is to say, mounted to the door on a side of the inner wall 1008 opposite the passenger cabin 103 at approximately the same height as the armrest 1017. In this an-angement the inlet 802 of each blower 302, 303 is aligned with the recess 1019 of the armrest 1017 such that the axis of rotation 806 of each blower extends through the recess 1019. The bend 418, 419 of each of the first and second ducts 401, 402 projects into the recess 1019 defined by the armrest 1017. By projecting into the recess 1019 the radius of curvature of the bend 418, 419 of each of the ducts 401, 402 may be increased. As a result airflow through each duct is turned from the radial direction to the axial direction (relative to the blowers 302, 302) more gradually, and so the restriction to an airflow through each duct 401, 402 is reduced.

In the example, the air conditioning system is configured to draw the first and second airflows in from the passenger cabin through the first and second ducts 401, 402, pass the first and second airflows over the first and second sides 707, 708 respectively of the Peltier device 301, and subsequently discharge the first airflow to the passenger cabin 103 of the vehicle and the second airflow to the first compartment 1011 of the door 104. The first airflow, having been heated or cooled by thermal exchange with the first side 707 of the Peltier device may thus be used to heat or cool the passenger cabin 103. The second airflow, having absorbed waste heat from, or rejected heat to, the second side 708 of the Peltier device, may be discharged from the compartment 1011 of the door 104 to atmosphere.

The first and second ducts 401, 402 are each arranged to draw air from inside the passenger cabin 103. The inlets 410, 411 of the first and second ducts 401, 402 are open through an underside of door 104 to a footwell region 1020 of the passenger cabin 103, such that the first and second blowers 302, 303 may draw first and second airflows from the footwell region 1020 of the passenger cabin 103. The third and fourth ducts 403, 404 are arranged to direct the first and second airflows over the first and second sides 707, 708 respectively of the Peltier device 301. The outlet 428 of the vent 407 of the fifth duct 405 is open through an upper portion of the inner wall 1008 of the door 104 to the passenger cabin 103. Thus, the fifth duct 405 may duct the first airflow to the passenger cabin 103. The sixth duct 406 is arranged to extend through an opening in the partition wall 1009, such that the outlet 427 of the sixth duct 406 is open to the interior of the first compartment 1011. A seal 1018 is provided about the sixth duct 406 to seal between the exterior surface of the duct 406 and the opening in the partition wall 1009.

Thus, the sixth duct 406 may duct the second airflow to the compartment 1011 of the door 104.

The fourth and sixth ducts 404, 406, which duct the second airflow are arranged to extend between the third and fifth ducts 403, 405 respectively which duct the first airflow, and the compartment 101 L As a consequence the first airflow within the third and fifth ducts 403, 405, is thermally insulated from the compartment 1011 and from the exterior of the vehicle by the fourth and sixth ducts 404, 406. This has the advantage that the first airflow is thermally insulated from the compartment and the exterior of the vehicle and so is less likely to he undesirably heated or cooled as it flows through the third and fifth ducts. It is particularly desirable that the fifth duct is thermally insulated from the exterior of the vehicle to avoid heating or cooling of the first airflow flowing from the Peltier device to the passenger cabin. Excessive and/or uncontrolled heating or cooling of the first airflow while passing through the fifth duct would complicate control of the passenger cabin air temperature.

As illustrated, the air conditioning system is mounted with the Peltier device extending in generally the same plane as the door 102. The Peltier device is oriented with the first side 707 facing towards the passenger cabin 103 and the second side 708 facing away from the passenger cabin 103 towards the exterior of the vehicle. Mounting the Peltier device with the second side 708 facing away from the passenger cabin 103 towards the exterior of the vehicle has the advantage that 'waste' thermal energy radiated by the second side 708 will tend to radiate primarily outwardly of the passenger cabin rather than into the passenger cabin. Furthermore, this arrangement simplifies the arrangement of the fifth and sixth ducts 405. 406 which duct air from the first side 707 of the Peltier device 301 to the passenger cabin 103 and from the second side 708 to the compartment 1011.

Thus, the first blower 302 may be operated to draw a first airflow from inside the passenger cabin 103 in through the first duct 401. The first blower 302 may then expel the first airflow through the third duct 403, across the first side 707 of the Peltier device 301 where the first airflow may exchange heat energy with the first side 707, and though the fifth duct 405 to inside the passenger cabin 103. Conversely, the second blower 303 may he operated to draw a second airflow from inside the passenger cabin 103 through the second duct 402. The second blower 303 may then expel the second airflow through the fourth duct 404, across the second side 708 of the Peltier device 301 where the second airflow may exchange heat energy with the second side 708, and through the sixth duct 406 to the first compartment 1011 of the door 104. As illustrated, the second airflow flowing through the sixth duct 406 actuates the valve flap 501 of the valve assembly 408 to the open position in which the duct 406 is open to the compartment 1011. The second airflow may subsequently he discharged from the first compartment 1011 to atmosphere via the vent aperture 1016. Thus, an airflow through the door 102 may be established flowing into the compartment 1011 from the sixth duct 406, downwardly through the compartment, and outwardly through the vent aperture 1016 to atmosphere via the channel defined between the underside of the door 104 and the upper surface of the sill 1005. Thus, controlled heating or cooling of the passenger cabin environment may be realised.

As previously mentioned, the foregoing description of air conditioning system 108 and door 102 is applicable also to air conditioning systems 109 to 111 and door 105 to 107. 30 Thus air conditioning systems 109 to 111 arc mounted to one of doors 105 to 107 in substantially the same way that air conditioning system 108 is mounted to door 104, and function in substantially the same way as air conditioning system 108.

Claims

Claims 1. A vehicle comprising: a passenger cabin; a door to the passenger cabin; and an air conditioning system comprising: a Peltier device; a blower for directing an airflow over a side of the Peltier device; and ducting for ducting air to an inlet of the blower; wherein the blower is mounted within the door with the inlet facing the passenger cabin.
2. A vehicle as claimed in claim 1, wherein the air conditioning system discharges the airflow to the passenger cabin.
3. A vehicle as claimed in claim I or claim 2, wherein the door comprises an armrest.
4. A vehicle as claimed in claim 3, wherein the blower is mounted behind the armrest.
5. A vehicle as claimed in any one of claims 1 to 4, wherein the ducting projects into a recess defined by the armrest.
6. A vehicle as claimed in any one of claims 1 to 5, wherein the blower draws air through the ducting from inside the passenger cabin.
7. A vehicle as claimed in any one of claims 1 to 6, wherein an inlet of the ducting is located on an underside of the door.
8. A vehicle as claimed in claim 6 or claim 7 wherein an inlet of the ducting is located in a footwell of the passenger cabin.
9. A vehicle as claimed in any one of claims 1 to 8, wherein the Peltier device is mounted to the door.
10. A vehicle as claimed in any one of claims 1 to 9, wherein the blower draws air in through the inlet in an axial direction and expels air in a radial direction.
11. A vehicle as claimed in any one of claims 1 to 10, wherein the airflow is discharged to the passenger cabin through an outlet located on the door.
12. A vehicle as claimed in any one of claims 1 to 11, wherein the Peltier device is located downstream of the blower.
13. A vehicle as claimed in any one of claims I to 12, wherein the Peltier device comprises a further side, and wherein the Peltier device is mounted to the door with the side facing towards the passenger cabin and the further side facing away from the passenger cabin.
14. A vehicle as claimed in claim 13, comprising a further blower for directing a further airflow over the further side of the Peltier device.
15. A vehicle as claimed in claim 14 wherein the further airflow s discharged to outside the passenger cabin.