Sodium borohydride (NaBH 4 ) is attractive as a fuel for fuel-cell electric vehicles (FCEVs) and fuel-cell hybrid electric vehicles because of its high energy density. We proposed and constructed a high-density hydrogen generation system that generates a large amount of hydrogen by hydrolysis of powdery NaBH 4 . However, our ability to conduct long driving tests was restricted by the low hydrogen generation rate at the start of the proposed system, particularly under low temperature. To overcome this problem, we added a citric acid solution catalyst at the start, thereby increasing the rate of hydrogen generation by a factor of 25 compared with the case of using a conventional nickel catalyst. In addition, we confirmed that using such a rapid hydrogen generation system had little effect on the power generation characteristics of a 100-W fuel cell, and we succeeded in conducting our driving tests of a FCEV fueled by powdery NaBH 4 .

Fuel cell hybrid electric vehicle (FCHEV) is strongly attractive as a zero emission vehicle. However, FCHEV has not been used widely by current state. One of the reasons is the construction cost of infrastructure such as hydrogen gas station is too expensive. As a solution, several high-pressure hydrogen gas tankless FCHEVs have been proposed. One of them is FCHEV fueled by sodium borohydride (NaBH4). This paper shows advantages and disadvantages of NaBH4 at using this material for FCHEV as the fuel. Moreover, a novel hydrogen gas supply system fueled by sodium borohydride for fuel cell is proposed. In addition, the specification and drive characteristics of the micro FCHEV that is fueled by hydrogen gas from a tank and is constructed to compare with hydrogen gas tankless FCHEV is reported.

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The acceleration and deceleration rate of the train depend on the tractive force. When the wheels of the train slip on the rails, the electric torque is decreased to avoid the continuous slipping. This reason is that the tractive coefficient between the wheels and the rails has a peak at a certain slip velocity and the over slipping should be avoided. But this adhesive phenomenon is not clearly examined or analyzed. Thus we have developed new adhesion test equipment, and we measured the tractive force with this equipment, and clarified the adhesive phenomenon. Then, we proposed a maximum tractive force control in the slip region and verified the validity of the proposed control scheme.

SUMMARYThe acceleration and deceleration rate of a train depends on the tractive force. When the wheels of a train slip on the rails, the torque is decreased to avoid continuous slipping. This is done because the tractive coefficient between the wheels and the rails has a peak at a certain slip velocity. But this adhesive phenomenon has not been clearly examined or analyzed. For this purpose, we have developed new tractive test equipment. In this paper, we measure the tractive force with this equipment, and clarify the adhesive phenomenon. Then we propose new tractive force control and verify the effectiveness of this control scheme.