機車安全帽的密不通風造成騎士的不舒服一直是個機車騎士頭痛的問題，本研究主要以實驗方式探討一個改良的通風安全帽散熱的能力，在機車行進中將氣流導入新設計通風安全帽內部之降溫效果。試驗方式是設置一組人頭模型，其內部均勻繞線圈再供應穩定電源以模擬人體的自然發熱，再安裝上安全帽以試驗風洞給予定數風速，分別測試內部降溫情況與散熱效果。加熱瓦數共分成四組2W、4W、6W、10W，風速分成四組0km/h、20km/h、40km/h、60km/h，先以風速0km/h測試無風速時不同瓦數下的溫度分佈，再以其溫度分佈延續試驗以20km/h、40km/h、60km/h風速下分別測量新式通風安全帽與傳統安全帽之降溫效果。試驗結果在0km/h風速下新式通風安全帽與傳統安全帽無明顯降溫差別，當風速提高時傳統安全帽溫差無明顯降溫，新式通風安全帽則是風速越大，降溫效果越明顯，且在風速較低時會有較大的溫降，以發熱功率3W在T3a點為例，當風速從0加速到20km/h時可降溫達7.16℃，當風速再由20km/h加速至40km/h可降溫2.1℃，當風速從40km/h加速至60km/h可降溫1.3℃。

In Taiwan, helmet laws for motorcycle riders were officially implemented on June 1st, 1997. All riders and passengers are required to wear safety helmets when riding motorcycles. According to statistics (source from Bureau of Health Promotion), wearing safety helmets not only protect the riders, but also greatly reduces the risk of injury and death from traffic accidents.

To better understand helmet use in Taiwan, the Institute of Transportation, Ministry of Transportation and Communications (1977) conducted a survey and found that helmet laws were supported and highly praised. However, inadequate ventilation and the inconvenience of carrying them are the main factors that influence people’s willingness to wear helmets.

Because Taiwan is located in a subtropical zone and the climate is hot and humid, most riders don't like to wear helmets. Due to inadequate ventilation and uncomfortableness, riders sweat a lot, especially in the summertime. Furthermore, helmets are perfect breeding grounds for bacteria because of the humidity in the storage compartment. Hence, it is liable to cause seborrheic dermatitis or illness resulting from improper cleansing.

To increase the willingness of wearing helmets, a new safety helmet is designed to improve the ventilation problem. With this new design, the wind will flow across the head to remove the heat.

This study investigated the ability of an improved ventilation cooling helmet by experimentation. Test mode is to set up a model of a head, wrap coil evenly on the inside, and then send a steady supply of power through it to mimic the body's natural heat. Then, install the helmet with a steady wind speed to test the internal cooling effect. Heating wattage is divided into four groups: 2W, 4W, 6W, and 10W. Wind speed is also divided into four groups; 0km/h, 20km/h, 40km/h, and 60km/h. The cooling effect of both the traditional helmet and the new ventilation helmet was tested by first testing the different wattages of temperature distribution at a wind speed of 0km/h, and then again at wind speeds of 20km/h, 40km/h, and 60km/h. The results of 0km/h wind speed showed no significant difference in cooling effects between the traditional and new ventilation helmets. However, as wind speeds became stronger, the traditional helmet still showed no significant cooling effect while the new ventilation helmet showed that the stronger the wind speed, the greater the cooling effect. Plus, lower wind speeds showed greater temperature drop. Take heating power 3W at T3a point as an example. When the wind speed accelerated from 0 to 20km/h, the temperature cooled down 7.16 ℃. When the wind speed accelerated from 20km/h to 40km/h, it cooled down 2.1 ℃. And when the wind speed accelerated from 40km/h to 60km/h, it cooled down 1.3 ℃.

The traditional helmet design mainly emphasized on safety, but there was no awareness for demanding ventilation. According to the study, the highest temperature could be increased by 20 degrees and reach up to 50℃, which can be very harmful to riders in the long run.

However, the new helmet design is featured with the cooling effect, no matter that the wind speed is 0km/h or 20km/h. With intake valves on helmets, riders can choose to close the valves to keep warm in winter or to open them to have better ventilation in summer. Also, compared with the wind speed at 0km/h, riders can feel the cooling effect more when the wind speed is 20km/h. Hence, this new design is very suitable for the riders in urban areas. The wind speed, in fact, is equal to the speed of the motorcycles. The heat can be easily reduced by air convection, which is indeed the most economic and simple method.

In the future, there are two things that can be further discussed and researched: to enhance the cooling performance and to verfiy the helmet structure. In fact, the design for air vents and air channels is a key factor that will have an effect on ventilation and cooling performances. This study did not research a better designm, but helmet structure design, such as air vent position, hole size, and rod materials and position, are recommended to be taken into consideration and modified in the future in order to improve the ventilation. Though it cannot be denied that the air vent’s design may possibly reduce protection to riders, the helmets with appropriate air vents have proven to still meet the requirements and also comform to the standard norm CNS 2396-Z2009. Moreover, the inner shell of traditional helmets are normally furnished with soft lining and sponges, which are at lower density to protect the head, whereas this study laid emphasis on ventilated helmets (utilizing rods which are at higher density). Hence, it will need the further verification between these two structures.

1. 蔡益堅、王榮德，“台北市機車使用者戴安全帽對預防頭部外傷效果分析＂，台大公共衛生研究所碩士論文，1990
2. 中華民國國家標準CNS 2396，Z2009“騎乘機車用防護頭盔＂，2007 年5 月14日修訂公佈。
3. 顏重岳，“機車安全帽之有限元素動態模擬＂，國立陽明大學醫學工程研究所 碩士論文，1995。
4. 王秋華，“機車安全帽護顎之有限元素分析＂，國立成功大學醫學工程研究所 碩士論文，1998。
5. Liu, X., Holmer, I., 1995. Evaporative heat transfer characteristics of industral safety helmets. Applied Ergonomics 26(2), 135-140.
6. Hsu, Y.L., Tai, C.Y., Chen, T.C., 1999. Improving thermal Properties of industrial safety helmets. International Journal of Industrial Ergonomics 26, 109-117.
7. ASHRAE, Thermal Comfort, ASHRAE handbook Fundamental, ASHRAE(1997).
8. 周文生、陳惠堂“騎乘機車強制戴安全帽之成效分析＂，警學叢刊；29﹝5﹞185-202，1999。
9. 張嘉原，“建立耦合式衝擊模型以研究機車頭盔的保護效果＂，國立中正大學機械工程研究所 碩士論文，1999。
10. 林豐福，“機車駕駛行為與事故風險評估＂，交通運輸研究所，2003。
11. 劉宗韶，“散熱系統應用於安全帽之人因評估＂，國立成功大學工業設計學系研究所碩士論文，2008.6月.
12. 王啟川，“熱交換器設計”，五南出版社，2003.