BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a first embodiment of a capacitance fuel volume measuring apparatus for a fuel cell of the invention;
FIG. 2 is a perspective view of a second embodiment of a capacitance fuel volume measuring apparatus for a fuel cell of the invention; and
FIG. 3 is a front view of a third embodiment of a capacitance fuel volume measuring apparatus for a fuel cell of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of a first embodiment of a capacitance fuel volume measuring apparatus for a fuel cell of the invention. The capacitance fuel volume measuring apparatus for a fuel cell comprises a fuel supply device 1 for supplying fuel to the fuel cell 3 and a control unit 2 comprising means for measuring the fuel volume.
The fuel supply device I comprises a fuel tank 11, which is a hollow structure forming a containing space for storing fuel 15 for the fuel cell 3. A first parallel metal board 13a and a second parallel metal board 13b are disposed in the containing space of the fuel tank 11. The first parallel metal board 13a and the second parallel metal board 13b are correspondingly disposed; in a preferred embodiment, the first parallel metal board 13a and the second parallel metal board 13b are disposed in parallel at the peripheral surface of the containing space to form a capacitor 13, and a substance disposed in the containing space of the fuel tank 11 serves as a dielectric material of the capacitor 13. Consequently, the capacitance of the capacitor 13 can be utilized to determine the volume of the fuel 15 in the fuel tank 11.
Furthermore, the control unit 2 is electronically connected to the capacitor 13, and comprises means for transforming capacitance to fuel volume. For a preferred embodiment, the control unit 2 can be implemented as a processor or a circuit, and the means for transforming capacitance to fuel volume of the control unit 2 has an algorithm for calculating the volume of the fuel 15 in the fuel tank 11 according to the capacitance of the capacitor 13. Corresponding information between the capacitance of the capacitor 11 and the volume of the fuel 15 in the fuel tank 11 can be obtained by experiments and stored in the means for transforming capacitance to fuel volume of the control unit 2.
Furthermore, the corresponding information between the capacitance of the capacitor 13 and the volume of the fuel 15 in the fuel tank 11 can be in a form of a function. Referring to FIG. 1, the functional relation is determined by the physical characteristics of the capacitor. In the first embodiment of the invention, the distance d between the first parallel metal board 13a and the second parallel metal board 13b and the effective area A of the first parallel metal board 13a and the second parallel metal board 13b are predetermined, and the capacitance C of the capacitor 13 can be obtained by the control unit 2. Thus, a corresponding effective permittivity E can be calculated by the formula C=(εA)/d, and a volume of the fuel 15 or a liquid level height of the fuel 15 can be further calculated from the effective permittivity ε.
FIG. 2 is a perspective view of a second embodiment of a capacitance fuel volume measuring apparatus for a fuel cell of the invention. As above-mentioned, 7 the capacitor 13 can be formed such that the containing space of the fuel tank 11 is formed between the first parallel metal board 13a and the second parallel metal board 13b. Accordingly, the first parallel metal board 13a and the second parallel metal board 13b of the capacitor 13 can be disposed parallel to the liquid level of the fuel 15, as shown in FIG. 1, or can be disposed perpendicular to the liquid level of the fuel 15, as shown in FIG. 2.
FIG. 3 is a front view of a third embodiment of a capacitance fuel volume measuring apparatus for a fuel cell of the invention. In this embodiment, the first parallel metal board 13a of the capacitor 13 is slidably disposed in the containing space of the fuel tank 11, and an elastic element 12 is disposed between the first parallel metal board 13a and a peripheral surface of the containing space of the fuel tank 11. Another surface of the first parallel metal board 13a is configured to contact the liquid level of the fuel 15. Thus, the elastic element 12 is configured to provide an elastic force along a direction to urge the first parallel metal board 13a against the liquid level of the fuel 15 such that the first parallel metal board 13a maintains contacting the liquid level of the fuel 15. In this way, the effective permittivity ε directly corresponds to the permittivity of the fuel and the liquid level height of the fuel, and the liquid level height of the fuel effectively corresponds to the distance d between the first parallel metal board 13a and the second parallel metal board 13b (since the difference between the liquid level height and the distance d is constant). As a result, the distance d or the volume of the fuel 15 can be obtained by calculation according to the corresponding information or the functional relation stored in the means for transforming capacitance to fuel volume of the control unit 2.
Furthermore, the elastic force provided by the elastic element 12 is along the direction to urge the first parallel metal board 13a against the liquid level of the fuel 15. Since the elastic force is configured to act urge the first parallel metal board 13a, the elastic element 12 can be disposed in, but not limited to, a position between the first parallel metal board 13a and the peripheral surface of the containing space of the fuel tank 11.
In the capacitance fuel volume measuring apparatus of the invention, the control unit 2 can be disposed in the fuel supply device 1 or in the fuel cell 3.
While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
Patent Application
20070272008
