Design of Windshields with New PVB Interlayer for Enhanced Noise Reduction and Weight Savings 2003-01-2858
Several windshield constructions are designed and tested for the objectives of weight savings and improved vehicle wind noise. They include standard windshield constructions representing typical production windshields installed on most vehicles today, and acoustic windshield constructions of different glass thickness with weight saving and NVH improvement as the design objectives. The acoustic windshields contain an acoustically enhanced polyvinyl butyral (PVB) interlayer, Vanceva™ Quiet. The windshield constructions are tested for transmission of external airborne noise in laboratory and wind noise and road noise on high-speed test tracks. Laboratory study shows significant opportunities for both improved acoustics in 1500 Hz to 6000 Hz frequency region - a key range for wind noise and airborne noise transmission - and weight savings. Full scale NVH testing on high-speed tracks at 80 to 160 kmph shows that acoustic windshields made with the same production glass as the standard windshields reduce vehicle wind noise by as much as 6 dB. Testings with a thinner and lighter acoustic windshield reveal that the windshield improves vehicle wind noise by as much as 3-4 dB, at a 15% weight saving.
While thinner and lighter windshield has recently been the trend in automotive glazing for significant weight savings, it has also been the NVH limitation to designing quieter car interior. The present study indicates that the windshield can be designed and made quieter with the acoustically enhanced PVB interlayer.