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In hot climate regions, there is demand for improved thermal comfort for rear occupants in vehicles not equipped with a rear air conditioner. One solution to this challenge is a circulator mounted on the ceiling. The circulator is a product designed to enhance thermal comfort for occupants by circulating the air in the cabin. The conventional circulator design, which employs a cross flow fan with a large cross section, juts into the cabin space, because it is difficult to package. Consequently, the challenge for the circulator is to provide thermal comfort for rear occupants while taking up the minimum cabin space under the ceiling. To solve this challenge, that is, to enable a substantially thinner structure, while retaining the same level of air flow delivered as before for the same thermal comfort as the conventional circulator, we divided the structure into an air outlet and an air blower.

As a method of maintaining thermal sensation and comfort inside a passenger compartment, not only a conventional HVAC system but also a combination of a HVAC system and other devices such as seat heaters, a steering wheel heater, ventilation seats are increasing. This research developed a method to evaluate thermal sensation of a human body when using these various thermal control devices. This method can evaluate the heat balance of the human body by calculating the amount of heat exchange between a human body and the external environment, and it takes into consideration the influence of heat exchange by heat conduction with seats or a steering wheel. The human thermal model is made by dividing a human body into various segments, and it is the model that considers heat transport by blood flow for each segment.

The number of idle-stop vehicles is rapidly increasing in recent years, and air-conditioning technologies that extend engine stopped time while maintaining the cabin comfort are required. When the engine stops during idle- stop mode, the air conditioner also stops functioning. To maintain cabin comfort, the engine is restarted to work the air-conditioning cycle, which reduces the fuel saving effects. As a countermeasure, a cold storage air conditioning system has been proposed. The system extends engine non-operation time by using cold storage for generating cool air while the engine is stopped. We have integrated this technology into an evaporator, which is used in the air-conditioning cycle, and the system has a short cold storage period and a necessary cold release period. This report describes its concept and effects.

Deceleration patterns of an expert driver will be formulated using the perceptual risk index for approach and proximity of a preceding vehicle as an example of comfortable braking pattern. It will be shown that the formulated braking pattern can generate smooth deceleration profile uniformly for many conditions of approaching conditions. In addition, brake initiation timing of expert driver will be successfully formulated using the alternative index. Finally, an automatic braking system will be proposed based on the formulated brake initiation model and the velocity profile. Twenty five expert drivers experienced the automatic braking installed in an experimental car. It will be shown that the proposed system can generate smooth profile and realize secure brake patterns based on subjective evaluation.