Frankfurt Motor. Show 95 glazing trends: shape and colour. Automotive glass

Transcription

1 Automotive glass Frankfurt Motor Show 95 glazing trends: shape and colour The article shows the main developments that illustrate the direction in which automotive glazing is headed: interchangeable single framework, transparent roof for a complete canopy of glass, flushing and wrapping windows for roof encapsulation - fixed or removable, and colour coordination between the glass and car body. The glassmakers' products at the show are examples of what might be appropriate to meet carmakers' co-design. Giovanni Manfré* MG CONSULT 118

2 From the general automotive point of view, it is evident that, compared to previous shows, Japanese carmakers appear less innovative and competitive, especially in the area of technical innova- General remarks At the Frankfurt Motor Show, held in September 1995, the following tendencies were evident: the reduced number of Japanese cars present at the show, the absence of carmakers' real innovative concepts and the addition of new shapes and new colours. Furthermore, Mercedes luxurious stand suggested an unconventional idea - the car s evolution into a product of nature. However, probably the most innovative ideas presented at the show were examples of an interchangeable body on a single framework as shown in Figure 1 for Mercedes. Glassmakers perspective The ideas that were conveyed from the carmakers present at the show to the glassmakers can be divided into three categories: - transparent roof, fixed or sliding, coordinated with backlight and windscreen in order to create a single transparent pavilion. This concept is not only a styling exercise, but also delivers the following messages: desired vision, more personalised and improved driver contact with the external environment. All of which can be achieved by the transparent pavilion which should also provide additional freedom for designers; - flushing and wrapping profile between glazing and roof, not only for aerodynamic reasons but also for style and market demand. Regarding innovative materials and processes, encapsulation and extrusion gasket technologies will be quite useful; Fig. 1 The Mercedes Benz Daimler Vario demonstrating four cars in one - colour coordination is necessary due to the fact that with the increasing number of paint and upholstery colours available on the market for the car body. Monocolour glazing certainly reduces the number of matching colours, especially some colours. For instance, green matches better than blue. Safety is also taken into consideration (Figure 11) relative to the colour contrast between glazing and the car body. Regarding the glassmakers point of view in terms of competition, this paper describes Flachglas and Sekurit Saint-Gobain products exhibited at the show. Flachglas showed that by using multi-functional glazing (stratified glass with a metallic PET film embedded between the usual two adhesive layers), it might be possible to satisfy nearly all of the carmakers property requirements. A modern technological concept for globally differentiating innovative multi-functional glazing. On the contrary, Saint-Gobain exhibited a wide range of products and technologies, each with a special main property, in an attempt to satisfy the market s present and future demands. A marketing-oriented strategy with a high level of pragmatism: the product can only be presented once it is possible to mass-produce it. Flachglas demonstrated EC glass in the hope of obtaining a flexible EC film for laminating in order to follow its global strategy. Particular attention was given to Sekurit Saint- Gobain s new dark tail Venus, with interest also being shown in the competitive Sundym product by Flachglas. A wider range of dark tail glass should be expected for carmakers with further information and functions on low UV transmission and different colours (green, grey and others in the future) and in addition to solar energy reduction. Automotive perspective 119

3 tions and new models; their presence has drastically decreased since the 93 and 91 shows. Furthermore, in the automotive components area, the Japanese have nearly disappeared. However, an important point to mention is that the Tokyo Motor Show took place shortly after the Frankfurt show, on 25 October It was also apparent that the German automotive companies and their international subsidiaries (Mercedes, BMW, VW, Audi, Ford, Opel, Porsche, Seat, Skoda) took advantage of this show and introduced their new cars. The new ideas however were limited to modern models lacking truly innovative technical parts and performance: it was a kingdom full of new shapes and colours only. Real R&D results have nearly disappeared, even in the show s literature, to make space for other parameters, which may be more easily understood Fig. 2 A view of the back portion of the break model Vario which must use dark tail glass Fig. 3.1 Mercedes E-class 1.5 model Fig. 3.2 The Mercedes Coupé SI 500 by the customers. The five important automotive dimensions related to the distinctive strategic car maker s philosophy seemed to be nearly avoided: performance, comfort, safety, environment and personalisation. Generally, particular attention was given to personalisation (shape and colour). For the safety dimension, only the airbag s presence as a passive safety component (which has been adopted by 37% of the cars) can be considered a real success. Therefore, it is difficult to compare the differences among the (exhibited) cars following a distinctive innovative automotive orientation which should point out at least some of the five vehicle dimensions mentioned above and certainly required for car making evolution. As a consequence, it is not easy to classify the actual connection between the car maker s need and the component maker s need, including glazing. Only Mercedes seems to give priority to environmental and personalisation (style) dimensions: the vehicle must be developed and function as a product of nature. With an extraordinary stand, Mercedes tried to demonstrate its global ecological strategy: even interior plastics should be replaced by natural materials composed of well designed elements that are mixed by workshop specialists. The car must grow like ice that crystallises from the water in a pond. A beautiful poetical concept, worth trying, but how much space does this leave for the actual pragmatism usually applied by the carmakers? The real innovative concept seemed to be con- 120

4 Fig. 4 The BMW Coupé 850SI Fig. 5 The Renault transparent pavilion fined to the goal of obtaining multipurpose interchangeable vehicles from a single framework structure. For the multi-purpose attempt, as in the total transparent roof pavilion which will be described later, Figure 1 shows the example of Mercedes Daimler Benz with the Vario Research Car, already previewed at the Geneva Motor Show in March 1995: four cars in one. But with just simple adjustments, the Vario changes its appearance completely. The single piece body structure, comprising the roof, side panels and rear section can be removed and replaced by another version, transforming a break into a convertible, saloon or pick-up vehicle. The four cars in one concept certainly implies different glazing properties especially in the actual modular body part. In fact, a second example of a modular car was shown by Opel with the concept car MAXX which, thanks to the space-frame body made of extruded aluminium profiles, can be adapted to change from a small car to a break by a complex hydraulic system not yet completely defined and shown only on a panel monitor at the show. This idea will certainly affect glazing with mechanical characteristics and weight suitable for the interchangeable body and the actual matching between the forward vision, which remains fixed, and the rear vision, which must change accordingly. In Figure 2 the rear glazing of the break module of the Vario uses a dark tail glazing with high visible transmission (TL>50%), completely different than the other modules, assuring rear visibility and internal lighting. This concept of a modular rear part of the vehicle seems to open a new trend of innovative glazing suitable for the interchangeable part of the body. Canopy glazing: windscreen, roof, backlight in a monotransparent pavilion The number of cars developed with a transparent continuous pavilion roof comprising the windscreen and backlight, is certainly increasing. The solution could be a monolithic canopy or three-section neatly joined in a flushing mode. One example is shown in Figure 3.1, which is the Mercedes E-class 1.5 model for the near future chosen from 200 designed models. Figure 3.2 illustrates an already developed example: a Mercedes Coupé SI500 presented at the show. The BMW Coupé 850SI in Figure 4 and the Renault in Figure 5 are further examples of the transparent pavilion. Figure 6 demonstrates that the transparent sunroof is not confined to cars marketed at the upper levels, but also to small cars such as the Mercedes Vision A. An intermediate step of this concept has al- 121

5 ready been adopted in a glazed sliding sunroof presented by Webasto (Figure 7). This figure illustrates the Webasto concept of total sunroof transparency in four separate sheets that are able to slide one on top of the other in order to allow air to enter. All the examples presented in this paper and some others that were exhibited at the show were developed to prove that the transparent pavilion was not conceived for stylistic reasons but because of the public s demand for more personalised models. Designers and engineers believe that this transparent surface is one of the best solutions because it permits safety, comfort, elegance and improved aerodynamics. Improved vision and better contact with the external environment during driving also result from this design. The solution also allows styling freedom. Other examples of transparent pavilions were presented in the concept cars of Hyundai, Ford, Mazda (CU- X) and Mitsubishi, Nissan, Honda. The Webasto transparent sliding mobile sunroof was adopted nicely onto a new Porsche model (Figure 8). This model certainly received a number of compliments at the show. The principle of Webasto is applied by Porsche s new model in a very suitable way and confirms the transparent pavilion tendency. With this concept, movement of the central part Fig. 6 The Mercedes Vision A car Fig. 7 The Webasto glazed sunroof diagram of the transparent glass sunroof lets the central section slide under the fixed backlight. This stylistic concept certainly leaves space for innovation by glassmakers who must also guarantee the same internal comfort and suitable airconditioning and heating systems for both the summer and winter. Of course, the solar control and switchable glass will become a necessity and new opportunities will appear for the glassmakers. All these solutions might leave some penetration of the transparent plastic glazing at least in a central part of the pavilion. Flushing gasket and wrapping glazing on the roof In the past, the flushing gasket was continuously perceived in the lateral window for aerodynamic purposes, especially after the advent of encapsulation technology. The present orientation appears to increasingly involve the windscreen and the backlight for two reasons: aerodynamics and the styling need for continuous profiles between glazing (transparent) and the rest of the body (opaque and/or transparent). Many examples of innovative or concept cars display the successful profile coordination between the glazing and the roof (see Figure 9). In Figure 9, VW s new Polo demonstrates notable continuous profile coordination between the windscreen (and the backlight) and the roof, nearly wrapping the surface in an aerodynamically flushing way. Figure 10 illustrates an example of a Sekurit backlight with the upper part bent in a way so as to obtain a wrapping surface between the glazing and the roof, thus allowing for a continuous flushing aerodynamic profile increasingly desired by the car designer. For the glassmakers it seems that this evolution has to simultaneously face gasket technology and the wrapping bending perimetrical shape of the glazing which has to suit the window frame in a 122

6 continuous profile with the rest of the car body. This shaping peripherical round glazing design will contribute aerodynamically more than a complex spherical shape. In fact, the aerodynamics are more affected by the shape of the perimetrical border than by the spherical mode of the global surface, at least for the windscreen. The Mercedes Benz-E class research drawing (see Figure 3.1) of the definitive models chosen from among 200, exhibited in a panel at the show, can be taken as a future decision. Even the example of Renault shown in Figure 5 can be used as a good example of continuous profile flushing and wrapping of the glazing and roof, nearly perfection (see also Figure 10) considering a backlight manufactured by Saint-Gobain. Colour coordination and vision safety Fig. 8 The Webasto sunroof on a Porsche Fig. 9 Front view of the VW Polo Fig. 10 An example of Sekurit Saint- Gobain wrapping backlight A drastic car show conclusion can be drawn by saying first of all that no one, so far in the vehicle world, has paid enough attention to colour coordination especially between the colour of the glazing and the colour of the external and internal parts of the car body (some attempts were made by Fiat when developing the Bravo and Brava models recently launched in Turin, Italy). In fact in any class level there is a tendency to have a unique colour of glazing (see Figure 11 as an example for Mercedes) which should be chosen to fit the external and internal colours of the paint and upholstery. Styling apart, even the visibility, especially in bad weather should be involved. It is easier for the driver to see an on-coming car when there is a higher constrast between the glazing and the bodywork. It is time that carmakers convince glassmakers to develop coloured glazing that offers the same high-performance or at least to choose a colour which can be coordinated with a wide range of colours and upholstery. It would also be quite successful if the coloured glass were equipped with multifunctional optical and solar control characteristics. One further consideration is that there were still too many cars at the show that had different glazing, produced by more than one glassmaker, on the same car. The colour difference was extremely noticeable, especially in the reflection, even in the vehicles targeted at the upper level markets. Glazing materials and glassmakers The automotive industry glazing competition at the Frankfurt Show 95 was confined to Pilkington, alias Flachglas and SIV, and Sekurit Saint- Gobain. PPG was present at the event providing commercial and technical information to fair visitors. It was clearly noticed that two ways of presentation were performed, at least judging how each 123

7 was set-up at their respective stand: a multifunctional glazing being developed at Flachglas, leaving other special glass and technology to SIV; Saint-Gobain on the contrary showed a series of different glass to pragmatically meet the market demand. Therefore, the description of the main innovative products in this paper should be read in the direction of the two perceived ways shown to satisfy the present competition. Product description by global technology It seems that by laminating a suitable metallic (silver-based coating) polyester film sandwiched between two adhesive layers, Flachglas can obtain a satisfactory multifunctional glazing like: - Siglasol: a solar control reflecting IR. It reflects sunlight with a metallic PET (55 micron thickness and silver multilayer based coating) embedded between a PVB normal adhesive in stratified clear glass (2.1/1.5 mm thickness); - Noise reduction by the Flachglas Sigladur glass which is fabricated with the same principle (metallic PET of Siglasol). The difference of the acoustic spectra is 3-5 decibels compared with a normal stratified glass. - With the same concept as Siglasol and Sigladur, it is also possible to add a property of antifog glass. There is a 4 C difference between internal and external surfaces with this method. - In addition, other properties are obtainable in multifunctional missions like better impact performance for lateral stratified tempered glass and antenna backlight performance for radio, TV, telephone, communication and navigation sys- Fig. 11 Mercedes class-e cars with colour-tinted glazing Fig. 12 An example of the Siglasol principle combining antennas for radio, TV, navigation, satellite, etc. tems by a special design conductive metal strip device. Figure 12 is an example of the same Siglasol principle equipped with a set of several antennas by a special metallic trail designed in the PET metallic surface (radio, TV, telephone, navigation, satellite, communication). Therefore, in conclusion, with a single laminating process, it is possible to produce a multifuntional glazing or the complete set of differential properties suitable for the whole car, which was very well presented at the Flachglas stand. The multifunctional glass of the Siglasol glazing concept might cover all glazing of a vehicle: windscreen, side, backlight and sunroof. The collaboration between Flachglas-Southwall (metallic film producer) and Monsanto (PVB producer) seems to have succeeded. Furthermore, the agreement does not let other worldwide glassmakers use the Southwall film. So the problem for other glassmakers can be overcome by finding another metallic film supplier, who should be available in the near future. The laminating process has already been developed by other glassmakers or transformers, the product cannot be patented as it has been a known art for many years beginning with aerospace glazing. Product description by market selection A series of different kinds of glazing from Saint-Gobain each with a very particular aim and produced with an advanced quality control process: bilayer (weight reduction), diversity antennas, solar control IR absorbing or IR reflecting, reduced internal re- 124

8 flection, noise reduction, water-repellent. Sekurit Saint-Gobain IR reflecting direct coating windscreen is a solar control glazing which shows the best performance of thermal comfort inside the vehicle predicted by the software Carcon II able to distinguish the temperature distribution of materials and air in the different zones of the passenger compartment. The Multidiversity antenna (radio, TV, telephone navigation system) is obtained by printed wires (serigraphy). The diversity of the Sekurit Saint-Gobain antenna can also be obtained by well designed direct coating on glass surfaces. The complex shape tempered backlight (see Figure 10) is in line with the most advanced shaping technologies similar to that applied to the Opel Tigra backlight (Sundym Flachglas shaped by SIV) and the well wrapped higher part of any backlight (Figure 13) which is in line with the continuous profile demand of the car body between the glazing and the roof as pointed out previously in the paper. In Figure 13, the new encapsulation Saint- Gobain technology, called Pop Out applied to an Audi backlight which makes it possible for a mechanic to eventually substitute the glass without breaking it. This concept also follows indications concerning recycling strategy: - weight reduction with the well-known bilayer; - hydrophile and water-repellent coated glass to increase visibility in the rain and to reduce the Fig. 13 The new Saint- Gobain Pop Out encapsulation technology use of the wipers during driving in the rain; - the definitive launching of the socalled dark tail glass with the trade mark Venus for backlight, rear-side windows and sunroof in green and grey. Two types of Sekurit Venus grey dark tail glass as part of the complete series can be used as an alternative to green thermosolar for backlight and side back glazing in line with the increasing demand of colour coordination, see colour coordination between glazing and car body by rendering. This special control dark tail glass should be described in detail because it can be chosen as the last example of product competition among the main glassmakers worldwide to satisfy the needs of the public and already followed by the carmakers and adopted with enthusiasm by the stylists. The solar control glass Venus by Sekurit Saint-Gobain, is available in two types: Solarit, low transparency TL = 35% visible range, very low in total solar energy reduction TE; Thermosolar with quite high transparency TL = 55% in visible range but only quite low in total energy transmission TE. Both are available in two colours. Sundym from Flachglas is a similar competitive glass on the market. The properties of Sundym and Venus seem to be similar except for the fact that Sekurit s product comes in two colours. The wider colour choice makes colour coordination easier. Furthermore, the choice should not only be made by comparing the TL and TE results but also in the percentage of UV absorbing (skin and interior materials deterioration effects) and the special IR (thermal sensitivity) transmission. *Technical Director MG Consult Srl - Italy 125 Entire content 1996 by Artech Publishing S.r.l.