As we design the future of transportation we constantly challenge ourselves to do better, use old materials in ways not used before, and use new material to create the previously unattained. Use lighter weight materials to increase fuel economy. We continue to design for style. The automotive glass designer maybe called upon to use non-traditional materials for traditional openings. They may have the opportunity to fill openings other than a windshield or backlite with glass. They also may be asked to have their glass do more than act as a translucent panel. Glass has many uses due to its resistance to extreme thermal changes and good structural integrity. Glass is such a versatile commodity, increasing more useful as we develop apps, touch screens, and interactive surfaces. In this article, I will look at the technological challenges and opportunities for using glass in areas not normally used in the automotive field, as you may know it. Unique ways glass is, can, and maybe used. I will profile everything from exotic cars to family crossovers to glass covered engine bays to interactive “smart” side windows.
The Pininfarina P4/5 was never meant to strictly be a concept car, but a mind-blowing street machine. James Glickenhaus, a film director and stock exchange magnate who wanted the ultimate Ferrari commissioned Pininfarina to re-body an Enzo. In March 2005 Glickenhaus, an avid car collector, was approached by Pininfarina who asked if he was interested in commissioning a one-off car. Glickenhaus replied that he would like a modern Ferrari P, and in June of that year he signed a contract with Pininfarina to produce the car including the price, approximately US$4 million though in an interview he said “I feel they gave me more than I expected”. Glickenhaus purchased the last unsold Enzo Ferrari and upon receipt of the car he took it to Pininfarina to be redesigned similar to his 1967 Ferrari 330 P3/4 chassis 0846 which he also delivered to Pininfarina. The car picks up where the late 1960s P-series Ferraris left off, the last being the 330 P4.
This time the car is all carbon fibre, shrink-wrapping the Enzo’s mighty 485 V12, which is visible through the clear black (deep tint glass) ventilated engine cover. Glass would be unique and still provide the structural integrity needed. The glass louvered engine bay is still one the most talked about designs on this automobile. Special attention was paid to its aerodynamic impact and how it impacted the sound the car makes.
The Lotus 2010 Lotus Evora 414E Hybrid
The Lotus 2010 Lotus Evora 414E Hybrid is so-named because of its 414 horsepower output, which is derived from two electric motors driving each of the rear wheels independently via a single speed geartrain that’s integrated into common transmission housing. In this way, the vehicle is able to vector torque to either of its rear wheels for additional stability. Each of the electric motors is rated at 295 pound-feet of torque, which should provide for some exhilarating acceleration action–expect the 0-60 mph sprint to take less than four seconds. It features a wraparound cockpit glass most of us would call the windshield and windows is what really grabs your attention as you move alongside the car.
With the windows being frameless, and with the A-pillar being blacked out, the wrap around effect is maximised with the large piece of glass in front raked so far back in the Evora. Further setting it apart from a standard Evora, the 414E Hybrid Concept is done in satin-finish copper paint and crowned with a unique glazed roof panel/transparent engine bay cover complete with a cool graphic that recreates the look of a printed circuit board. There’s no point in driving such a car and handing out sound samples to fellow motorists and passersby’s without showing them where that beautiful sound is coming from. And that’s dramatized with black wire mesh covering the gaping holes around the glass covering.
More and more companies are integrating much more glass and polycarbonate into a vehicle that was primarily the domain of sheetmetal, such as integrating glass into the decklid.
The common complaints to this design are visibility into the cargo area and addition heat load in the cabin.
The 250 P5 Berlinetta Speciale concept cars built as collaboration between Ferrari and Pininfarina. The concept features many design elements which appeared on later Ferrari models. The P5 featured about the concept was that it featured a glass-covered mid-engine, much like many of the modern Ferrari do today.
1968 Ferrari 250 P5 Berlinetta Speciale Pininfarina Concept
Designed by Pininfarina in 1968, the Ferrari P5 was first shown at the 1968 Geneva Motorshow. The Ferrari 250 P5 Berlinetta Speciale was constructed using a P4 chassis and had a 3 litre mid-mounted V-12 engine. The car was a study in aerodynamics and design and it helped influence later day production Ferrari’s, most notably the clear rear glass over the engine.
1970 De Tomaso Mangusta
The Mangusta shared more with concept cars of the period than its contemporaries. This is especially true of the gullwing engine doors which only provided access to half the glass covered engine bay. This unique touch was part of design originally intended by Giorgetto Giugiaro formerly of Bertone. The Mangusta formula was the same as that for Pantera: a Ford V8 engine (albeit a 302 rather than a 351C) midships in a sleek Italian body. In the case of the Mangusta, stylist Giorgetto Giugiaro added the unique touch of gullwing doors covering the engine bay and luggage compartment, and he conveniently buried the small-block mill under the bodywork in the process.
McLaren P1 glass roof and engine bay
A key part of the interior (I know you are thinking an exterior panel) was the glass roof. It would have been very tight and a quite dark interior. Designers need to get more light into the cabin. McLaren used aircraft-grade glass, the lightest on the market, super thin which saves weight, obviously which on this or any vehicle is critical. The teardrop-shaped glass canopy is the crucial aspect of the design. McLaren’s engineers evolved the glass canopy from current Le Mans car principles and it dictated the surface shape of the body panels. From the inside, the glasshouse of the McLaren P1 feels light and spacious. Visibility is good and to deflect glare, the two roof panels are solar reflecting.
A similar passion for the wider view is taking shape in passenger cars. Large double sunroofs are growing in popularity. Ford says orders for its expansive sunroof option are double what had been projected; in two crossover models, the Edge and Explorer, half of the buyers spent the extra money for it.
New types of glass have helped make the trend possible. Today’s glass is treated to filter out ultraviolet rays and reduce heat load. This is made possible in three different ways.
- Solar Reflecting
- Solar Absorbing
- < 20% Light transmitting glass.
The panoramic roofs have also fared well in independent safety tests.
The Insurance Institute of Highway Safety has tested a couple of vehicles with panoramic-style sunroofs, and claims that there is no indication that these roof designs aren’t as strong as roofs with conventional sheet metal. However, this doesn’t mean that vehicles with glass roof panels would be as safe in rollovers as vehicles without them. Glass roofs could break or pop out if the bond fails.
The latest version of Cadillac’s sunroof on the new SRX covers 70% of the roof area and has a power retractable shade.
Volkswagen says that the glass roof of the Beetle introduced in 2012 is 80% greater in area than its predecessor’s and that it blocks 99% of ultraviolet radiation and 92% of the heat energy. It should be noted that clear glass will block out approximately 90% of the heat load as well.
Visible Light Transmission is the percentage of visible light that is transmitted through the glass. The VLT is measured in the 380-780nm wavelength range perpendicular to the surface.
Tinted float glass is produced by adding metal oxides during float glass production. Apart from its function in an aesthetic sense, tinted glass is primarily designed to reduce solar heat gain, UV and glare as well as heat load inside a vehicle.
Glazing types vary in their transparency to different parts of the visible spectrum. For example, a glass that appears to be tinted green as you look through it toward the outside will transmit more sunlight from the green portion of the visible spectrum, and absorb/reflect more of the other colours. Similarly, a bronze-tinted glass will absorb/reflect the blues and greens and transmit the warmer colours. Neutral Grey tints absorb/reflect most colours equally.
This same principle applies outside the visible spectrum. Most glass is partially transparent to at least some ultraviolet radiation, while plastics are commonly more opaque to ultraviolet. Glass is opaque to far-infrared radiation but generally transparent to near-infrared. The four basic properties of glazing that affect radiant energy transfer–transmittance, reflectance, absorptance, and emittance.
Tinted glass achieves its performance by absorbing solar energy and so is sometimes referred to as heat absorbing glass. This heat absorbing quality means the glass is thermally stressed so some thicker or darker products may need to be toughened (chemically treated) to avoid thermal stress breakage. Toughened glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Chemically strengthened glass is typically six to eight times the strength of float glass; this makes it ideal for panoramic roofs. Tinted float glass can be processed into heat strengthened, toughened, laminated, and curved glass. Tinted glass products are sourced from quality float glass manufacturers including Guardian, Glaverbel, Asahi and Pilkington.
Grey float glass is the traditional medium grey tinted glass characterized by its low light transmission and good control of solar heat and glare. This glass is manufactured in thicknesses ranging from 4 – 12mm.
The roofs of some cars with panoramic glass, like Kia Optima, for example, are painted in dark reflective colours or covered with materials designers call foils to give the impression of a roof made entirely of glass.
And some are just plain cool. The glass roof on the folding hardtop of the 2012 Mercedes-Benz SLK roadster changes from dark to clear at the touch of a button. Voltage passing through particles in the glass causes them to realign, lightening or darkening the roof and made good use of Photovoltaics.
The creation of innovative concepts for urban mobility has seen MINI grow into the successful brand we know today. The roof of the MINI Rocketman Concept also puts on an extraordinary light show. The full-surface glass roof is supported by illuminated structural braces to recreate the look of Britain’s Union Jack flag. When not illuminated, the longitudinal, horizontal and diagonal braces glow a bright Porcelain White.
Volvo is considering a high-end luxury wagon that would be based on the Concept Estate and wear V90 badges.
The concept is also fitted with a full glass roof, which is only supported structurally on the longitudinal roof rails, the header, front and rear header. No mid roof cross car structure. Features such as this are taking full use of advanced glass design.
I like the clean application of the blackout for UV protection and to hide molding and possibly interior trim.
Volvos glass engineers and stylists agreed the dot matrix pattern was not aesthetically beneficial in this case.
Dot matrix patterns are generally used on passenger car windshields to break up the abrupt solid blackout line. They also aid in diffusing light.
Normally, a single panoramic sunroof is of fixed laminated glass or an encapsulated assembly. The other type is made of either tempered or laminated glass, and can also be encapsulated. When you think of auto protection, features like airbags and safety belts immediately come to mind. But the glass that surrounds you also plays a critical role in keeping you safe. Nothing does it better than laminated glass.
The reason is that unlike tempered glass, laminated glass is actually two pieces of glass bonded together by a plastic interlayer. When shattered, the fragments stick to the plastic, reducing the risk of ejection and helping to increase safety in an accident or collision.
Laminated glass delivers twice the occupant ejection mitigation protection. The outstanding safety provided by laminated glass is why it’s been a legal requirement for new windscreens in Europe since early 80s. Today, automakers can offer laminated glass throughout their vehicles, including side windows and sunroofs, to offer even greater protection. Glass has inherently poor acoustic properties, but laminated glass, alone or combined with additional glass plies to form a sealed, insulating glass unit, outperforms other glazing assemblies. Laminated glass reduces noise transmission due to the PVB layer’s sound-dampening characteristics.
The Future Now
The Volvo Concept Estate would be an ideal vehicle to utilize developing technology by General Motors Research and the students from the FUTURE LAB at Bezalel Academy of Art and Design in Israel. The idea behind this was to conceptualize new ways to help rear seat passengers, particularly children, have a richer experience on the road.
The project was inspired by studies indicating car passengers often feel disconnected from their environment especially during long family trips. GM asked the Bezalel students to turn car windows into interactive displays capable of stimulating engagement that fostered curiosity and encouraged a stronger connection with the world outside the vehicle. The idea was to create advanced windows capable of responding to vehicle speed and location that could augment real world views with interactive enhancements to provide entertainment and educational value. If such interactive windows were put into automotive production they likely would use electronically charged “smart glass” technology, which is capable of variable states of translucence and transparency, and can reflect projected images. Smart glass is increasingly used in architectural and display applications, rarely seen in cars. Photovoltaics or “smart glass” technology would only be able to be used on the vehicles side windows as it could not transition fast enough to clear as needed in the windshield, and this technology would have to fail to a clear state.
The future is exciting and the possibilities seem to be endless for innovative uses in in glazing. With the rapid development of mobile apps and the readymade substrate of glass, I cannot wait to see the new world technology comingling with the old school design.