Hydrogen Fast Filling to a Type IV Tank Developed for Motorcycles

Hydrogen is one of possible alternative energy sources to replace fossil fuels in transportation sector. Hydrogen fuel cell vehicles (FCVs) are expected to play an important role in the future. A tank to store compressed hydrogen is necessary for the FCVs due to the long-distance driving as well as that of conventional vehicles. It is also necessary that refueling the tank should be completed within a few minutes because of user convenience. In this study, a fast filling of high pressurized hydrogen is concerned for a Type IV tank which has been developed for motorcycles. Due to restrict the temperature rise up to 85 degrees Celsius for fuel cell system integrity, different scenarios of fast filling up to 70 MPa are investigated. A pressure ramp rate is kept at a constant value with or without intermissions. All cases applied in this study indicate that the gas temperature in the tank does not always exceed 85 degrees Celsius until the end of filling. The temporal decrease of inside gas temperature is appeared after the rapid rise in the early 10 seconds of filling. It is estimated that the heat produced by compression of hydrogen transfers to the inside wall immediately, since the inner surface area to tank volume ratio becomes large as the tank size is small. Therefore the decrease of gas temperature obtained in this study is a characteristic phenomenon in small size tanks.