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To create a society based on hydrogen energy in the near future, it is necessary to clarify the influence of hydrogen on the mechanical, physical and chemical properties of the materials used for hydrogen energy systems. The rubber O-rings used in the high-pressure sometimes suffer from the decrease in durability due to decompression failure, which is influenced by several factors. From this viewpoint, sensitive factors for the durability of rubber O-rings were evaluated by using a L18 orthogonal array. A high-pressure durability tester, which enables the rubber O-rings to expose repeatedly high-pressure hydrogen gas at arbitrary test conditions, was employed.

Honda R&D has developed a throttle-by-wire (TBW) system that meets the needs of motorcycles where the attitude of the vehicle body is controlled by operation of the throttle. To gain high response and following for the throttle valve, we employed a new adaptive control algorithm. The newly developed system has an idling combustion stabilization function and a three-dimensional control function for the throttle-opening map based on running gear and engine speed. With those functions, we improved the controllability of the motorcycle, especially for small throttle openings. Furthermore, we improved the feeling of the limiter control used in maximum-speed limitation. For the overall system, intake system related devices are consolidated to improve the layout flexibility and expand the mounting options on the motorcycle.

Rubber O-rings installed in hydrogen tanks for fuel cell electric vehicles are repeatedly exposed to high pressure hydrogen gas. Exposure to high pressure gas sometimes causes cracks as a result of blistering after decompression. The degree of blister damage is influenced by material, environmental conditions such as decompression rate, and sealing shape such as squeeze ratio. Focusing on environmental conditions out of these influential factors, in this study, a high pressure hydrogen durability tester which exposes rubber O-rings repeatedly to high pressure hydrogen gas at arbitrary test conditions was developed. Using this tester, the influence of hydrogen pressure and temperature on blister damage and permeability was investigated for sealing materials used conventionally for high pressure equipment.