Automakers spend a lot of time focusing on noise, vibration and harshness (NVH). That’s because many consumers demand vehicles that are as quiet as possible.

DETROIT—Fiat Chrysler, Magna Interior Inc., Grupo Antolin and the U.S. Department of Energy have collaborated on a project that reduces the weight of car doors by 42.5 percent without a dramatic increase in cost. Using a holistic approach, engineers looked at the door as a complete system that could integrate everything available on the market today.