Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/84—Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
  • H05B3/86—Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields the heating conductors being embedded in the transparent or reflecting material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60J—WINDOWS, WINDSCREENS, NON-FIXED ROOFS, DOORS, OR SIMILAR DEVICES FOR VEHICLES; REMOVABLE EXTERNAL PROTECTIVE COVERINGS SPECIALLY ADAPTED FOR VEHICLES
  • B60J1/00—Windows; Windscreens; Accessories therefor
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
  • H05B2203/013—Heaters using resistive films or coatings

Definitions

• the invention relates to glazing, which constitutes at least part of the roof or, roof, of vehicles.
• the properties required at this stage of this evolution were essentially optical.
• the glass roof had to offer sufficient light transmission to produce the impression of “light opening”, but this same transmission had to remain within certain limits to keep the interior “private”.
• glazings are either in one piece or composed of several elements juxtaposed or not. Some of these glazings can be movable to release openings, others are fixed.
• Patent application EP 1 200 256 proposes in particular glazing units meeting this set of characteristics.
• most of the efforts have focused on the selectivity of the transmission, in other words on the relationship between light transmission and energy transmission, the most interesting being to achieve the best possible selectivity.
• two parameters have been systematically considered, the intrinsic selectivity of the glasses forming part of these glazings, in particular by an appropriate choice of compounds coloring these glasses, and the introduction into these glazings of dividers or of limiting, reflecting layers. or absorbing incident energy radiation.
• the heating of the glazing is preferably such that it leads the wall of the glazing facing the interior of the passenger compartment to a temperature close to that of the atmosphere of the passenger compartment or even slightly higher , so that the energetic radiation emitted by this wall towards the interior of the vehicle is of comparable size to that of the radiation which is emitted from the passenger compartment outside the vehicle.
• the transparent layers maintain perfect uniformity of transmission in the glazing, but their use can raise problems in terms of regulatory light transmission threshold.
• the power delivered is higher the lower the electrical resistance of the layer. If the power must be relatively high, the resistance 0 must be low.
• the resistance of the layers depends, among other things, on their thickness. To have a low resistance, a solution therefore consists in increasing the thickness of the layer. Even if we speak of "transparent" layers, the conductive layers do not exhibit total transmission, and this is all the more reduced as the layer is thicker. 5
• the heating of the side windows of vehicles is also subject to limitations, even if the light transmission may be slightly less than for the windshield, in particular as regards the side windows corresponding to the seats from the rear of the vehicle.
• the relatively limited dimensions 0 mean that the resistances usually remain in Umites for which, to obtain a sufficiently low resistance, the thickness of the layers does not pose of difficulty.
• the dimensions are of the order of those of windshields or even greater.
• the characteristics of the heating elements used in roofs likewise, are not conditioned by light transmission requirements.
• the layers used, whatever their thickness, are not such that the light transmission is adversely affected.
• the difficulty in the case of roofs can, where appropriate, for thin heating layers, come from the usual limits of deposition techniques.
• the usual techniques and materials for the formation of similar layers on glazing such as windshields can be used. It is also possible to use layers usually intended for building glazing. Common layers are especially metallic layers and particularly silver layers. It is also possible to use doped tin oxide type layers or any other conductive layer usually used on glazing.
• Preferred layer stacks are for example those with a double layer of silver having a structure of the type: dielectric / argeni / dielectric / dielectric silver
• the conductive metal layers are usually formed by vacuum deposition techniques. These layers are relatively fragile and, for this reason, preferably, are located on the faces of the glass sheets which are not exposed, in other words, they are preferably on the faces turned towards the interlayer of the laminate. If layers of this type are used on monolithic glazing, they are placed on your side facing the passenger compartment and, preferably, are protected by a dielectric layer resistant to abrasion.
• Very fine filaments are another way of forming the heating elements of roofs.
• the practice of using these threads leads to introducing them into ⁇ es laminated glazings, preferably in direct contact with one of the glass sheets and embedded in the polymer interlayer sheet.
• these are wires for example tungsten, of very small diameter, of the order of ten micrometers.
• the wires are spaced a few millimeters apart. Preferably they are wavy.
• wires which can be integrated into the windshields can also be used in roof glazing without causing vision problems.
• the laminated glazings previously proposed are in particular those which are the subject of publication WO 01/02167.
• These glazings have assemblies of glass which contain various coloring agents intended to favor, on the one hand, a lowering of the energy transmission TE, and, on the other hand, a control of the light transmission while retaining control over the color of the light transmitted in the passenger compartment.
• the energy transmission is kept as low as 15% or less and the light transmission for the examples given is less than 25%.
• the glazing constituting the roof may also include thin layers on one or the other of the glass sheets, so as to better control the opto-energetic characteristics thereof.
• sunscreen layers in particular based on metals such as silver, or on materials such as tin oxide doped with fluorine or antimony.
• These layers which make it possible to control the energy and light transmission in the passenger compartment, also offer the advantage of being able to serve as a heating layer for the glazing units considered insofar as they are also conductive. Answering the most delicate problems attached to these glazings, namely, on the one hand the control of the solar energy supply, and on the other hand the maintenance of comfort in winter, they therefore constitute particularly satisfactory solutions.
• a simple mode of regulation consists in imposing a temperature on the internal face of the roof glazing, which is substantially equal to the average temperature in the passenger compartment.
• sensors determine the two temperatures.
• the received signals are then compared and are used by a circuit for controlling the power supply to the roof heating circuit until the temperature of the roof is brought back to a temperature closer to that of the passenger compartment.
• the regulation can be adjusted in a more elaborate way to take into account if necessary the sunshine. In this case, the sensors still determine the influence of solar radiation inside the vehicle, to establish the control instructions for the regulation of the roof heating.
• the power available for heating the roof must be sufficient to allow the regulation envisaged under all the usual conditions of use.
• the power depends not only on the heated surface, but also on the climatic conditions in which the use of the vehicle is located. Given the uses envisaged, in temperate climates, the power delivered is advantageously between 400 and 1500w / m 2 .
• the attached single figure illustrates the thermal behavior of various types of roofs, under various conditions of use.
• a motor vehicle is equipped with a roof whose surface is approximately 1.2 m 2 .
• the vehicle is placed in a chamber thermostated at a temperature of -18 C C.
• the blower associated with the enclosure makes it possible to recreate the conditions of movement of the vehicle.
• the conditions are set using a dynamometer inducing a rolling resistance corresponding to the chosen speed.
• the reported tests are carried out for conditions corresponding to speeds of 50km / h for the first 30 minutes, and 80km / h for the rest of the tests.
• Measurements are made successively for a metal roof lined with a fibrous facing (curve 1), a laminated glass roof made up of two glass sheets of 2.1 and 2.1 mm thick respectively, assembled using a 0.76mm thick poly-vinyl but ral (PVB) interlayer sheet (curve 2), and of the same roof consisting of laminated glazing additionally comprising a conductive heating layer delivering two constant powers (765 curve 3, and 920 curve 4).
• the conductive heating layer consists of a stack of layers such as: dielectric / dielectric argeni / argenVdielectric
• This type of stacking is used in particular to form heated windshields.
• the comparison between the metal roof and the simple laminated glass roof clearly shows a difference which corresponds to a significantly higher loss in the case of glazing. This explains the feeling of cold felt by the occupants.
• the heated roof allows to find the same characteristics as for the metal roof for a power of 765w.
• a delivered power of 920 taking into account the surface of the roof, the flux balance is even slightly higher for the heated glazing compared to the metal roof, for the simulated speed conditions. This power is therefore likely to maintain the same comfort conditions for even higher speeds.
• Heating the roof glazing according to the invention therefore makes it possible, while retaining the glazing of roofs the properties which make them choose instead of traditional roofs, to avoid the thermal discomfort which was linked to the use of these roofs glazed.
• a determination of the thermal comfort perceived by passengers is carried out in the cabin of the experimental vehicle. The determination is made according to the protocol of ISO standard 10551. These are subjective evaluations carried out on a diversified sample of individuals. The tests are carried out on the one hand with the vehicle equipped with non-heated roof glazing, on the other hand with the same vehicle equipped with the heated roof delivering a power of 765. The assessment is made for the stationary and moving vehicle.
• the glazing heat compared to non-heated glazing, has a positive difference varying from 0.5 to 2 points, depending on traffic conditions, on the comfort scale which is set from 0 to 9. The most noticeable difference is noted for the stationary vehicle.
• the "subjective" assessment therefore confirms the advantage conferred by the use of heated roof glazing according to the invention.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Joining Of Glass To Other Materials (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=31501422

Family Applications (1)

Country Status (4)

Family Cites Families (10)

• 2002
  • 2002-08-05 BE BE2002/0467A patent/BE1015056A3/fr not_active IP Right Cessation
• 2003
  • 2003-08-04 AU AU2003266260A patent/AU2003266260A1/en not_active Abandoned
  • 2003-08-04 EP EP03784186A patent/EP1540994A2/de not_active Withdrawn
  • 2003-08-04 WO PCT/EP2003/008693 patent/WO2004016043A2/fr not_active Ceased

Non-Patent Citations (1)

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