Abstract: The present invention discloses a fuel mixing apparatus, comprising: a container capable of accommodating a fuel and comprising a first inlet, a second inlet, a first outlet and a second outlet; and a tank floating on the fuel inside the container, comprising a pair of openings and communicating with the second inlet and the second outlet through flexible tubes respectively. In addition, the present invention further provides a fuel cell system combing the fuel mixing apparatus and a fuel cell module. When the fuel cell system is tilted, the tank of the fuel mixing apparatus is capable of adjusting its location in accordance with the surface of the fuel, while the flexible tubes are still capable of keeping an unhindered passage for the gas and/or the liquid to enter or to be exhausted from the container smoothly.

Abstract: A fuel supplying and controlling method and a fuel cell apparatus are provided in the present invention, in which a fuel sensor-less control method and a fuel concentration sensor are combined together to stabilize the operation of the fuel cell apparatus. In one embodiment of the present invention, an optimum range of fuel concentration is determined using the fuel sensor-less control method and then whether the fuel cell apparatus operates within the optimum range of fuel concentration or not is monitored using the fuel concentration sensor as a first line of defense, while the fuel sensor-less control method is used as a secondary line of defense for monitoring.