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In recent years, start-stop systems have been implemented by many OEMs for improvement of fuel economy. When the engine stops, the occupant comfort typically deteriorates. Hence, the climate and fuel economy engineers are struggling to combine the passenger comfort and fuel economy. Especially in a vehicle cabin where the thermal environment becomes unsteady and highly non-uniform due to a start-stop. It is difficult to adapt any comfort evaluation index that have already been well established for a stationary/uniform space in building type environment in comparison to a vehicle cabin interior. The existing standard of ISO-14505-2 does not consider this for vehicle cabin interior condition. Hence, the authors have developed the occupant’s comfort prediction method under highly non-uniform condition and unsteady conditions and have established a new methodology [1].

Nearly all of the commonly used comfort predictors assume that the occupant is in a homogeneous environment, and are not fully effective in situations where this is not the case. In typical vehicle spaces, one commonly observes vertical temperature differences, radiant asymmetry, local air flows, and local body cooling. The purpose of this study is to describe a method for measuring non-uniform thermal environments using a new thermal manikin with controlled skin surface temperature. The manikin and its control logic are described, and an equivalent temperature based on the thermal manikin (teq) is proposed and discussed. To calibrate these methods, fundamental data were collected. For example, the clothed thermal manikin was tested in thermally non-uniform vehicle environments as created by solar radiation and HVAC system. The manikin-based equivalent temperature (teq) is shown to be effective at accounting for the effects of asymmetrical environmental conditions.