Embodiments of a clock generator and a clock generating method can use a delay locked loop. The door locks the slide to the rack and the air filter cover hinges to hold the air filter the door. This catalyst is suitable for maintaining a constant oxygen content in the tail gases and hence in the recycled gases. A pressure regulating device for absorbing a pulsation of the water supply device and absorbing the variation in the pressure in the fuel cell module is provided between the water supply device and the fuel cell module.