WO2005053980A2

WO2005053980A2 - Improvements in or relating to cabriolet vehicles

Info

Publication number: WO2005053980A2
Application number: PCT/GB2004/004998
Authority: WO
Inventors: Kevin Puddephatt
Original assignee: Nissan Technical Centre Europe Ltd
Priority date: 2003-12-02
Filing date: 2004-11-29
Publication date: 2005-06-16
Also published as: GB2408829A; WO2005053980A3; GB0327859D0; GB0426114D0

Abstract

A warning apparatus for a cabriolet-type vehicle having a roof structure movable between a first, closed position and a second, open position comprises sensor means for sensing the intensity of solar radiation falling on the vehicle and warning means for generating a warning to the vehicle user. The apparatus may be operable in response to operation by the user of a switch to select movement of the roof structure between the first and second positions. In one embodiment, if the measured intensity exceeds a predetermined level, the roof structure is not permitted to move between the first and second positions.

Description

IMPROVEMENTS IN OR RELATING TO CABRIOLET VEHICLES

The present invention is concerned with improvements in or relating to vehicles having retractable or foldable roof structures which can be folded away to expose the passenger compartment or cabin of the vehicle. In particular, the invention is directed to an apparatus for warning the occupant of such a vehicle of a high level of solar radiation and a potentially increased risk of sunburn. The invention is also directed to an apparatus for controlling the movement of the roof structure in dependence on the intensity of solar radiation falling on the vehicle.

Vehicles, such as automobiles, having folded roof structures are well known and are commonly referred to as "convertibles" or "cabriolets". There are two main types of cabriolet vehicle: the first, more common type is the "soft-top cabriolet" having a roof structure formed predominantly from a flexible fabric material which is stretched over a frame. The frame is collapsible between a non-folded position of the roof, wherein the material is stretched by the frame to define a roof covering the passenger cabin, and a folded position thereof, wherein the flexible material folds or creases naturally as the frame collapses to expose the passenger cabin. In the folded position, the collapsed roof is stored in a roof storage area located in the rear of the vehicle, either in a compartment disposed between the vehicle seats and the luggage compartment or seated on top of the luggage compartment or a parcel shelf thereof.

The second form of cabriolet vehicle is the "hard-top cabriolet". Hard-top cabriolet vehicles, which are comparatively rare, feature a so-called "retractable hard-top" (RHT) formed of two or more rigid panels which are pivotally connected together. A linkage, such as a parallelogram linkage, supports the panels and permits movement of the panels between a first, non- folded position of the roof structure and a second, folded position thereof. In the first, non-folded position, the RHT covers the passenger compartment of the vehicle giving the appearance of a conventional fixed-roof vehicle. In the folded position, the RHT is folded on the frame, each panel pivoting relative to the other, often in a " clam-shell" type movement. The folded roof structure is commonly stored in a roof storage compartment which frequently consists of at least a part of the vehicle trunk or luggage compartment.

In both types of vehicle, while the roof is in the folded position and stored in the storage compartment, the passenger compartment or cabin of the vehicle is substantially completely uncovered or exposed and the occupants therefore have little or no protection from the elements. Obviously, such vehicles are usually operated with the roof in the non-folded position during adverse weather conditions, such as during rain, snow, high winds or low temperatures. On the other hand, during periods of fine weather, the vehicle may predominantly be used with the roof in the folded position.

However, in such fine weather conditions, and with the roof of the vehicle in the folded position, the occupant may be exposed to high levels of solar radiation, with no protection afforded by the vehicle roof. It is well known that solar radiation, in excessive doses, can be extremely damaging to human tissue, particularly to the skin, and can lead to sunburn and, potentially, to certain forms of skin cancer. It is also known that repeated sunburns, even if not particularly severe individually, have an incremental effect which itself can increase a persons risk of developing serious skin cancers, including malignant melanoma, later in life.

The damaging effect of the sun is predominantly caused by ultraviolet (UV) radiation emitted by the sun. Although the level of UV radiation emitted is proportional to the intensity of the total radiation emitted by the sun (known as the "sun load"), it is not necessarily proportional to the temperature generated on the skin. Thus, it is quite possible to develop severe sunburn even during cool weather. Because of this, users of cabriolet type vehicles are particularly at risk of developing sunburn during periods of bright sunlight, when the roof of the vehicle is in the folded position, even though they may be unable to feel the onset of sunburn owing to the cooling effect of the air stream around the moving vehicle.

It is an aim of the present invention to provide an apparatus and/or method which addresses this problem. It is a further aim of the invention to provide a system for a cabriolet-type vehicle which monitors the sun intensity level and advises the user of the vehicle that there may be an increased risk of sunburn if the vehicle is operated with the roof in the folded position.

According to one aspect of the present invention, therefore, there is provided a warning apparatus for a cabriolet-type vehicle having a retractable roof structure and switch means operable to select movement of the roof structure between a first, closed position and a second, open position, the apparatus comprising sensor means for sensing the intensity of solar radiation falling on the vehicle in response to operation of the switch means and warning means for generating a warning signal in dependence thereon.

The warning means may comprise display means for displaying a value representative of the intensity of solar radiation falling on the vehicle.

The apparatus may further comprise conversion means for converting the measured intensity into predetermined units indicative of the risk of sunburn to the user. The predetermined units may comprise units of sun factor, sun index or sun unit. The conversion means may be connected between the sensor means and the display means.

In one embodiment, the display means comprises a dot matrix or LCD display, a warning lamp or a light on the instrument panel or combimeter of the vehicle. The sensor means may comprise a sensor for measuring the intensity of ultraviolet radiation falling upon the vehicle.

The indicator means may comprise means for generating an audible indication of the risk and/or the measured intensity. The indicator means may comprise a stereo or audio player or head unit of the vehicle.

According to another aspect of the invention there is provided a control apparatus for a cabriolet-type vehicle having a retractable roof structure and switch means operable to select movement of the roof structure between a first, closed position and a second, open position, the apparatus comprising sensor means for sensing the intensity of solar radiation falling on the vehicle in response to operation of the switch means and control means for controlling movement of the roof structure in dependence thereon.

The apparatus may further comprise drive means for moving the roof structure between the first and second positions in response to operation of the switch means, the control means being adapted to control the drive means in dependence on said intensity.

In one embodiment, in response to operation of the switch means, the control means is arranged to compare the measured intensity with a predetermined level and, if said intensity exceeds the predetermined level, to control the drive means such that movement of the roof structure from the first position to the second position is prevented.

The apparatus may further comprise warning means for generating a warning signal if the measured intensity exceeds the predetermined level. The control means may be arranged to move the roof from the non-folded position to the folded position on further actuation of the switch means within a predetermined period following generation of the warning signal.

According to a third aspect of the invention there is provided a vehicle having an apparatus as described in the preceding paragraphs.

According to a fourth aspect of the invention there is provided a method of operating a foldable or retractable vehicle roof comprising drive means for moving the roof between non-folded and folded positions thereof, control means for confrolling the drive means and switch means for selectively activating the control means, the method comprising, on actuation of the switch means, sensing the intensity of solar radiation falling upon the vehicle, comparing the measured intensity with a predetermined level and, if the intensity exceeds the predetermined level, preventing movement of the roof from the non-folded position.

The method may further comprise the step of generating a warning signal to a user of the vehicle.

The method may include the step of, on actuation of said switch means a second time within a predetermined time period and following generation of the warning signal, moving the roof from the non-folded position to the folded position.

The invention provides a means by which the user of the vehicle is warned that operation of the vehicle with the roof in the folded position could expose the user to the risk of sunburn. In a further embodiment of the invention, a warning is provided to the user if the user selects to move the vehicle roof from the non- folded to the folded position when the solar intensity exceeds a predetermined level. The control means may be arranged to prevent movement of the vehicle roof from the non-folded position to the folded position when the measured solar intensity falling on the vehicle exceeds a predetermined level. Furthermore, the roof may remain in the non-folded position until the user reselects movement of the roof to the folded position.

It will be appreciated that each described embodiment of the invention may be implemented either alone or in conjunction with one or more of the other described embodiments.

The present invention will now be described by way of example only, with reference to the accompanying drawings in which:

Figure 1 illustrates a first form of apparatus according to the invention; and

Figure 2 illustrates a second form of apparatus according to the invention.

Referring firstly to Figure 1, a first form of apparatus according to the invention is shown generally at 10. The apparatus 10 comprises sensing means in the form of a solar radiation sensor 12 which is located on the surface of a vehicle (not shown) at a position which may be permanently or predominantly exposed to sunlight.

The sensor 12, commonly referred to as a sun-load sensor, consists of an optoelectronic device, such as a photodiode, which is arranged to sense the intensity of radiation falling on the vehicle and to generate a voltage in dependence thereon. Sensors of this kind are described in, for example, US2003/0000174 and W099/24951. The structure and operation of such sensors will therefore be well understood by those skilled in the art and further details are not included herein. The sensor 12 is connected to conversion means in the form of a processor 14. The processor 14 is arranged to detect the voltage generated by the sensor 12 and to apply a conversion algorithm thereto to convert the signal from the conventional units of W/m² to an alternative unit such as sun factor, sun index or sun unit (SU). The conversion of the signal from W/m to the alternative unit can be achieved by means of any suitable algorithm, as will be well understood by those skilled in the art.

The processor 14 generates a indicator signal which is applied to a display unit 16. The display unit 16, which may be a dot matrix or LCD display, displays a visible indication of the calculated sun index, in dependence on the indicator signal applied thereto.

Where the vehicle is a convertible-type vehicle, having a roof which can be moved between non-folded and folded positions, this indication can be used to warn the vehicle user that the current solar intensity is such that operation of the vehicle with the roof in the folded position presents an increased risk of sunburn or other serious effects.

Referring next to Figure 2, this illustrates a modification to the apparatus of Figure 1. In this embodiment, the apparatus 10 is connected to a mechanism for moving the vehicle roof between non-folded and folded positions thereof. The mechanism, shown generally at 20, is conventional in form comprising a motor or other drive means 22 which is arranged to drive a mechanical linkage, such as a parallelogram linkage (not shown) on which the roof is mounted, between first and second positions, representative of the non-folded and folded positions of the roof, respectively.

The drive means 22 may comprise an electric motor or a hydraulic or pneumatic drive system having a pump and one or more actuators. The drive means 22 is connected to, and controlled by, a controller 24. The controller 24 is arranged to generate first and second drive signals in dependence on the position or status of a switch 26 which is connected to the controller 24.

The switch 26 is a three-position switch having first and second non-latching positions and an intermediate, off position to which the switch is resiliently biased. The switch 26 is arranged to be manually operated or actuated by the vehicle user thereby to select movement of the vehicle from the non-folded to the folded position and vice versa.

Also connected to the controller 24 is a second switch or sensor 28 which is arranged to sense whether conditions in the vehicle are right for movement of the roof. In practice, the switch 28 may consist of a micro switch which is actuated by means of a tonneau cover located in the luggage compartment of the vehicle. The system may require the tonneau cover to be moved into a specific position in which the switch 28 is actuated before the roof is permitted to be moved into the folded position.

In operation, the user actuates the switch 26, moving it into the first position and holding it there, thereby to select movement of the vehicle roof from the non-folded to the folded position. Movement of the switch 26 into the first position generates an actuation signal which is applied to the controller 24. The controller 24 receives the actuation signal and then checks to determine whether the switch 28 is in the correct position to permit movement of the roof into the folded position.

If the switch 28 is so positioned, the controller 24 generates the first drive signal and applies this signal to the drive means 22. On receipt of the first drive signal, the drive means 22 then drives the linkage connected to the roof in the appropriate manner so as to cause the roof to be moved from the non-folded to the folded position. Movement of the roof from the folded to the non-folded position is achieved by the user moving the switch 26 into the second position. The controller 24 generates a second drive signal which is applied to the drive means 22. The drive means 22 then drives the roof linkage in the opposite direction thereby to move the roof from the folded to the non-folded position. This operation of the roof of the vehicle will be well understood by the skilled artisan.

In the embodiment of Figure 2, the processor 14 of the apparatus 10 is connected to the controller 24 such that operation of the invention is as follows.

In addition to the display 16 displaying the current sun index, as described with reference to Figure 1, or as an alternative thereto, the apparatus 10 controls the operation of the mechanism 20. Specifically, if the user wishes to move the vehicle roof from the non-folded to the folded position, the switch 26 is moved into the first position generating the actuation signal which is applied to the controller 24.

On receipt of the actuation signal, the controller 24 generates an open_request signal which is applied to the processor 14. On receiving the open_request signalled from the controller 24, the processor 14 determines the current sun index (or intensity) and compares . this with a predetermined level. If the measured sun index exceeds the predetermined level, the processor generates a suspend signal and applies this to the controller 24. On receiving the suspend signal, the controller 24 delays or suspends generation of the first drive signal such that the drive means 22 does not operate and the vehicle roof remains in the non-folded position.

In addition, the processor 14 generates a second indicator signal which is applied to the display 16. The display 16 then displays the second warning signal which may be of a form such as "Risk of sunburn - do you wish to proceed?", or the like. The warning displayed by the display 16 advises the user that movement of the roof from the non-folded to the folded position may put the user at risk from sunburn or other detrimental effects and, either explicitly or implicitly, requests confirmation that the operation of the roof to the folded position should proceed. If the user wishes to proceed in spite of the warning, the switch 26 is again moved to the first position thereby to generate the first drive signal.

On receiving the first drive signal a second time within a predetermined period, calculated by means of a timer (not shown), the controller 24 generates the first drive signal which is then applied to the drive means 22 thereby to move the roof from the non-folded position to the folded position.

It can be seen, therefore, that when the intensity of solar radiation falling upon the vehicle exceeds a predetermined level, movement of the switch 26 into the first position by the user does not cause the roof to move to the folded position. Instead, a warning is provided to the user that movement of the roof to the folded position presents an increased risk of sunburn. A second operation of the switch into the first position is required to override this warning and to continue with the operation to move the roof into the folded position.

It will be appreciated that the present invention provides a useful warning to the user of a convertible-type of vehicle that weather conditions are such that there is presented a high risk of sunburn or other injury if the vehicle is operated with the roof in the folded position.

It will also be appreciated that there are a number of modifications and/or improvements which could be made to the embodiments described. For example, the sensor 12 may comprise a sun-load sensor which is conventionally provided on the vehicle for controlling the operation of the heating, ventilation and air conditioning (HVAC) system of the vehicle. This type of sensor is adapted to measure the heating effect of the sun on the vehicle and to control the speed of the cooling fan in dependence thereon. Conventionally, the sensor is more sensitive to infrared wavelengths of the solar spectrum, since this is what predominantly affects the heating of the vehicle. It is envisaged, however, that the range of the existing sensor could easily be increased or adapted to render it sensitive to ultraviolet wavelengths which have the greatest effect on sunburn and other sun-related conditions.

The processor 14 may comprise the conventional body control unit (BCU) provided on the vehicle whilst the display 16 may constitute a simple warning lamp on the vehicle instrument panel. Alternatively, where a multifunction display is provided on the vehicle, the warning can be displayed thereon. It is quite possible, therefore, that no additional hardware is required on the vehicle - a relatively simple software modification to existing hardware, possibly with additional connections between that hardware, could provide the required functionality.

In addition, or alternatively, the processor 14 and the controller 24 may be integrated into a single control unit, thereby reducing cost and weight. In one embodiment, if the sun factor exceeds the predetermined level, the processor 14 may be arranged to generate an emergency signal to the controller 24 which generates the second drive signal to cause the drive means 22 to move the roof from the folded position to the non-folded position. Thus, the vehicle roof is automatically moved from the folded position to the non-folded position in the event that solar intensity which exceeds the second predetermined level. On the other hand, if that second predetermined level is exceeded whilst the vehicle roof is in the non-folded position, the controller 24 may prevent the roof from being moved into the folded position, without the possibility of overriding by the user. In one embodiment, the sensor means 12 is not used and the sun factor is instead derived from information transmitted by local or national radio stations or other transmitted data.

The use of the terms "sun factor", "sun index" or "sun unit" refer to suitable units which permit an assessment or estimation of the likelihood of sunburn, or the level of risk thereof, to be made and are not intended to be limiting in any way.

The predetermined level may be selectable by the user by means of a suitable input device on the vehicle such as a keypad. Thus the warning may only be given, or the movement of the roof prevented, if the measured sun factor is higher than the level selected by the user.

The apparatus may be used with fixed roof vehicles, as well as convertible-type vehicles.

Claims

1. A warning apparatus for a cabriolet-type vehicle having a retractable roof structure and switch means operable to select movement of the roof structure between a first, closed position and a second, open position, the apparatus comprising sensor means for sensing the intensity of solar radiation falling on the vehicle in response to operation of the switch means and warning means for generating a warning signal in dependence thereon.

2. An apparatus as claimed in claim 1 wherein the warning means comprises display means for displaying a value representative of the intensity of solar radiation falling on the vehicle.

3. An apparatus as claimed in claim 2 further comprising conversion means for converting the measured intensity into predetermined units indicative of the risk of sunburn to the user.

4. An apparatus as claimed in claim 3 wherein the predetermined units comprise units of sun factor, sun index or sun unit.

5. An apparatus as claimed in claim 3 or claim 4 wherein the conversion means is connected between the sensor means and the display means.

6. An apparatus as claimed in any of claims 3 - 5 wherein the display means comprises a dot matrix or LCD display, a warning lamp or a light on the instrument panel or combimeter of the vehicle.

7. A control apparatus for a cabriolet-type vehicle having a retractable roof structure and switch means operable to select movement of the roof structure between a first, closed position and a second, open position, the apparatus comprising sensor means for sensing the intensity of solar radiation falling on the vehicle in response to operation of the switch means and control means for controlling movement of the roof structure in dependence thereon.

8. An apparatus as claimed in claim 7 further comprising drive means for moving the roof structure between the first and second positions in response to operation of the switch means, the control means being adapted to control the drive means in dependence on said intensity.

9. An apparatus as claimed in claim 7 or claim 8 wherein, in response to operation of the switch means, the control means is arranged to compare the measured intensity with a predetermined level and, if said intensity exceeds the predetermined level, to control the drive means such that movement of the roof structure from the first position to the second position is prevented.

10. An apparatus as claimed in claim 9 further comprising warning means for generating a warning signal if the measured intensity exceeds the predetermined level.

11. An apparatus as claimed in claim 10 wherein the control means is arranged to move the roof from the non-folded position to the folded position on further actuation of the switch means following generation of the warning signal.

12. A vehicle having an apparatus as claimed in any preceding claim.

13. A method of operating a foldable or retractable vehicle roof comprising drive means for moving the roof between non-folded and folded positions thereof, control means for controlling the drive means and switch means for selectively activating the control means, the method comprising, on actuation of the switch means by a user of the vehicle:

sensing the intensity of solar radiation falling upon the vehicle, comparing the measured intensity with a predetermined level;

and, if the intensity exceeds the predetermined level, preventing movement of the roof from the non-folded position.

14. A method as claimed in claim 13 further comprising generating a warning signal to a user of the vehicle.

15. A method as claimed in claim 14 further comprising, on actuation of the switch means a second time within a predetermined time period and following generation of the warning signal, moving the roof from the non-folded position to the folded position.

16. An apparatus constructed and arranged substantially as described herein with reference to the accompanying drawings.