In order to increase fuel cell vehicle mileage per filling, technologies have been developed to reduce the weight of the in-tank solenoid valve and boost hydrogen seal performance, both issues in increasing the pressure of a hydrogen storage and supply system.It was necessary for the in-tank solenoid valve for use at 70 MPa to display twice the pressure resistance of the previous model (for 35 MPa use). However, realizing the necessary increase in pressure resistance would increase the size and weight of the valve. The in-tank solenoid valve is provided with a check valve on the hydrogen filling side and a shut-off valve on the hydrogen supply side; these valves connect to the high-pressure hydrogen tank and supply and shut off hydrogen. As a means of reducing weight in the developed in-tank solenoid valve, the functions of these valves were integrated, making it possible to share the flow channels for hydrogen filling and hydrogen supply. The temperature sensor was built into the tank, and aluminum alloy was employed as the material for the valve body. These measures reduced the weight of the developed in-tank solenoid valve by 41% against the previous 35 MPa model.For the hydrogen seal, a structure that helps to ensure that the seal material is not damaged at a pressure of 70 MPa was adopted, and a high-strength seal material was employed. These measures made it possible to realize a high level of pressure resistance in the hydrogen seal.
Article of Honda R&D Technical Review Vol.28 No.1 (9 - 15)