The popularity of electric vehicles (EVs) and market adoption continues to rise as these vehicles becoming more advanced in their technology, and energy efficiency due to increased battery life. When building an electric vehicle, the batteries are usually positioned under the seats. Due to this design EVs often have higher seating positions, leading to the removal of sunshades to maximize headroom.
While the expansive roof glass and absence of the sunshade can create a sense of space and connection to the outdoors, they also allow more external sounds like wind, rain, and road noise to penetrate the vehicle.
To address this, SEKISUI S-LEC proposes a solution that significantly improves the acoustic performance of roof glass, ensuring a quieter and more comfortable driving experience.
SEKISUI S-LEC has verified the need for sound acoustic performance in roof glass and the effectiveness of S-LEC™ Sound Acoustic Film through actual vehicle tests.
To test the theory, “glass roofs without sunshade cause more noise in the cabin”, we conducted a test measuring sound pressure inside a vehicle equipped with a sunshade. By driving at a constant speed of 140 km/h – switching the sunshade to open and closed – it is observed that the sound pressure proofs opening or removing the sunshade allows more noise to enter the vehicle.
As the trend towards larger glass surfaces on the roof continues, better sound acoustic performance will be required.
To further validate the effectiveness of S-LEC™ Sound Acoustic Film, SEKISUI S-LEC performed wind tunnel tests on an SUV EV equipped with approximately 2 square meters of roof glass. Comparisons were made between standard laminated roof glass and roof glass incorporating S-LEC™ Sound Acoustic Film. We installed 4 dummy heads at both the front and rear seats to measure the sound pressure at the ear positions.
The results were striking: sound pressure was reduced by up to 3.2dB, with the most significant improvements observed at ear positions closer to the vehicle’s center. This reduction in sound pressure translates to a 3.7% improvement in the Articulation Index, meaning your conversations will be clearer, and your overall driving experience will be more serene.
Rain noise can be a significant source of discomfort in vehicles with large glass surfaces. We conducted several laboratory tests to assess the effectiveness of S-LEC™ Sound Acoustic Film in mitigating rain noise.
A microphone was placed 35cm from the glass to simulate the distance from the roof glass to a passenger’s ear. Under a simulated 40mm/h rainfall condition, the acoustic laminated glass with S-LEC™ Sound Acoustic Film demonstrated up to a 5.9dB reduction in sound pressure compared to the standard laminated glass.
The result shows laminated glass using S-LEC™ Sound Acoustic Film is highly effective in sound acoustic against rain noise and contributes to a quieter cabin.
From these vehicle and laboratory tests, SEKISUI S-LEC has confirmed the need for a sound acoustic performance in roof glass and the effectiveness of S-LEC™ Sound Acoustic Film.
For more information on evaluation methods and results or any questions about S-LEC™ Sound Acoustic Film, please do not hesitate to contact us.
SEKISUI S-LEC’s PVB interlayer laminated glass, S-LEC™ Film, provides a wide range of solutions to needs for panoramic roof glass, not limited to sound acoustic functions.
Adjusting the transmittance provides both a feeling of openness and sunlight control. It also contributes to the safety of the roof glass by preventing its shattering in the case of glass breakage. S-LEC™ Film cuts more than 99% of UV rays, protecting passengers’ skin in vehicles without sunshades. It can be combined with solar control performance, effectively cutting infrared rays as a heat source, providing additional comfort.
You can download more information on the wide range of lineups and technical data here.
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