Evaluation of Equivalent Temperature in a Vehicle Cabin with a Numerical Thermal Manikin (Part 1): Measurement of Equivalent Temperature in a Vehicle Cabin and Development of a Numerical Thermal Manikin
To be published on April 2, 2019 by SAE International in United States
Present paper is Part 1 of two consecutive studies. Part 1 describes three subjects: definition of equivalent temperature (teq), measurements of teq by a clothed thermal manikin in a vehicle cabin, and modeling of the clothed thermal manikin for teq simulation. After describing the definition of teq, a measurement method of teq by a clothed thermal manikin was examined. This study proposed two techniques: definition of total heat transfer coefficient between skin and environment in a standard environment (hcal) based on thermal insulation of clothing (Icl), and measurement method of Icl in consideration of area factor (fcl), which indicates the ratio of clothing surface to manikin surface area. Then teq was measured in an actual vehicle cabin by the proposed method under two conditions: cooling with solar radiation, and heating without solar radiation. The results showed that proper teq, including the effects of air temperature, air velocity and radiation, was measured. Subsequently to the teq measurements, a numerical thermal manikin was developed. The geometry of the clothed manikin was modeled by 3D laser scan. Then the evaluation procedures of teq using the developed numerical thermal manikin were defined, based on a heat exchange model in consideration of fcl effect. The evaluation procedures can be applied to all manikin control modes described in ISO 14505-2, namely constant temperature mode, constant heat flux mode and comfort equation mode. Finally the calculation accuracy by the numerical thermal manikin was confirmed under a uniform environment. The results showed good agreement with measurement. The numerical thermal manikin is applied to vehicle simulation in Part 2 and the simulation results are validated by comparison with the vehicle measurements in this part.