Recall your last marathon all-day, all-night drive—and the aftermath. Remember the aching back and neck, headache, sweating torso and ice-cold feet, the feeling of other-worldliness? The symptoms of uncomfortable vehicle seats include decreased concentration and tiredness that can lead to accidents. The Hohenstein Institute, Bönnigheim, Germany, has developed test methods for assessing the physiological comfort of vehicle seats, using special measuring devices that include an Upholstery Tester shaped like a human bottom.
A key factor governing driver comfort is the ergonomic design of the seat, which should offer mechanical support without forcing the body into an unnatural position. However, other comfort measures related to temperature and humidity form the basis of the Hohenstein Institute’s evaluation methods. Four of the most important factors in seat comfort: the driver’s heat perception on first contact with the seat, rapid moisture transport away from the seating material, thermal insulation that helps warm or cool the driver and moisture buffering that absorbs water vapor into the seat without making it feel damp. The Upholstery Tester, for example, is pre-heated to skin temperature and pressed into the seat. Heat sensors record the level of insulation upon first contact and after reaching body-seat temperature equilibrium. The Skin Model, a porous, heatable metal plate, releases water vapor to simulate sweating. Moisture sensors provide information about the seat material’s ability to wick moisture from the body and hold it in the material. For details, visit The Hohenstein Institute.