Search Results

This paper presents mathematical models of thermal interactions among an automobile passenger, the cabin environment, and a heated/ventilated seat. The model, which has the ability to predict the transient response of a driver in a highly non-uniform thermal environment, has been tested against subjective evaluations under simulated winter and summer driving conditions. The good agreement between model predictions and experimental measurements suggests that such a model can be a useful predictive tool in the design of a passenger thermal comfort system.

This paper presents a comprehensive steady-state numerical study for an occupant-loaded vehicle seat with internal heating under severe winter conditions. A participant-based postural study showed that the nominal peak occupant seat pressure was 6kPa on the seat cushion, and 2.5kPa on the backrest. Uni-axial compression tests also indicated non-linear stress-strain behaviors in seating. Using an internally developed 3-D numerical model, it was found that the thermal resistance from contact and clothing was uniform (hc=144W·K−1·m−2) throughout the occupied regions. Their contribution to the overall thermal resistance was relatively minor, however, compared to that of skin (hoverall=27.2W·K−1·m−2). The thermal-mechanical simulations were conducted at heat input levels between 20W and 80W, using I-DEAS 10 and the TMG package as the simulation platform. Comparisons was also made between occupied seat with deflected and non-deflected mesh.

A thermal/physical model of the dynamic interaction between an automobile passenger, the cabin environment, and a heated/ventilated seat is presented. The model considers the human body as being made of 21 distinct segments and three-layers. Simple mathematical models are presented to simulate heating and ventilation of cool air through the seat. The model has the ability to predict the transient response of a driver in a highly non-uniform thermal environment in terms of local and overall thermal comfort levels.

A thermophysical model of the dynamic interactions between an automobile driver and a heated seat is presented. The model uses the experimentally measured averaged load distributions to identify the local thermal resistances and to determine variations in temperatures of the seat, the driver's skin and clothing temperatures as a function of time. The model predicts a sudden temperature change in the seat surface temperature in contact areas. However, temperature differences due to the load distribution are found to be insignificant. The effective heat transfer coefficient in the contacted areas is determined to be about 145 W·K-1·m-2 for the contacted areas.