FIELD OF THE INVENTION
The present invention relates to a fluid metering apparatus, and more particularly to a fluid metering apparatus which is capable of detecting a physical characteristic of a fluid, especially volume of a liquid.
BACKGROUND OF THE INVENTION
The conventional fluid metering device is employed to measure a physical characteristic of a fluid such as concentration, density or quantity. Usually, the conventional fluid metering device is big in size with complicated parts and it results in higher cost. However, products, which are small in size with low costs, are getting important due to being demanded in the market. Taking the fuel cell system as an example, the fuel cell has a cell core to output power by means of the hydrogen-rich fuel, such as methanol, performing electrochemical reaction with oxygen. In the field of fuel cell application, in order to notify the user when the concentration of the fuel or the fuel storage is insufficient and when the fuel needs to be supplemented, it is required to detect liquid level and quantity of the fuel contained in the fuel container. Currently, both the concentration and the quantity of the fuel in the ordinary fuel container are detected with an expensive metering sensor but it is uneconomical if the costly metering sensor is largely utilized in portable electronic products. Further, there are many intermediate products or the like in the process of the electrochemical reaction and temperature of the fuel may change in accordance with electrochemical reaction. As a result, errors occur inevitably.
For overcoming the above-mentioned drawbacks of the prior art, a fluid metering apparatus according the present is provided.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a fluid metering apparatus which can measuring physical characteristics of the fuel such as concentration, density, liquid level and etc.
It is another object of the present invention to provide a fluid metering apparatus with which an electrical signal corresponding to a capacitance value, an inductance value or an impedance of a simple strip line component can be measured or any one of electrical signal of the preceding electrical signal combinations can be measured such that a corresponding physical characteristic of the fuel can be obtained.
It is a further object of the present invention to provide a fluid metering apparatus which can offer a reference electrical signal for correcting error resulted from other products created by the electrochemical reaction or change of temperature.
To obtain the aforementioned objects, the present invention provides a fluid metering apparatus, which comprises a fluid container and a metering device. The fluid container has a hollow part for storing the fuel, and the fluid metering device further comprises electrical metering means and data processing means. The electrical metering means detects electrical information caused by physical change of the fuel in the fluid container. The data processing means converts the detected electrical information into a physical characteristic of the fuel. The electrical metering means includes a measuring component, which further includes a strip line component, and the electrical information is an electrical signal selected from a capacitance value, an inductance value or an impedance value of the strip line component or any one electrical signal of the preceding electrical signal combinations.
The preceding electrical metering means includes several strip line components, which vertically extend along a direction toward a depth of the hollow part. The preceding data processing means includes saving the corresponding relationship between the electrical signal and a physical characteristic of the fluid. Moreover, the physical characteristic of the fluid is one of the liquid level, density of the fluid and concentration of the fluid.
Furthermore, the strip line component is fork-shaped strip line capacitance component, or further is a micro strip line component.
In addition, the electrical metering means further includes a second strip line component sealed with a specimen fluid which is identical with the fluid stored in the hollow part. The specimen fluid maintains at an initial state and temperature of the specimen fluid varies with the temperature of the fluid in the hollow part. Hence, influence resulting from temperature factor or other products created during the electrochemical reaction can be taken away from the reference electrical signal obtained with the second strip line component.
The preceding strip line component can be utilized in a fuel cell system and disposed in a fluid container for storing fuel. The strip line component can detect the physical quantity of the fluid and produce corresponding electrical signal.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features and advantages of the present invention will be more clearly understood to those who are skilled in the art through the following descriptions of the preferred embodiment with reference to the drawings, wherein:
FIG. 1 is a block diagram illustrating the components of a fluid metering apparatus according to a preferred embodiment of the present invention;
FIG. 2 is a perspective view illustrating the preferred embodiment of a fluid metering apparatus according to the present invention;
FIG. 3 is a side view illustrating the preferred embodiment of a fluid metering apparatus according to the present invention;
FIG. 4 is an enlarged diagram illustrating the components configured in a fluid metering device according to the preferred embodiment of the present invention;
FIG. 5 is a cross sectional diagram illustrating the preferred embodiment of a fluid metering apparatus according to the present invention;
FIG. 6 is an enlarged side view illustrating the components configured in a fluid metering apparatus according to another preferred embodiment of the present invention;
FIG. 7 is an enlarged side view illustrating the components configured in a fluid metering apparatus according to a further preferred embodiment of the present invention;
FIG. 8 is an enlarged side view illustrating the components configured in the fluid metering apparatus shown in FIG. 7; and
FIG. 9 is an enlarged side view illustrating the components configured in a fluid metering apparatus according to still a further preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.
Please refer to FIG. 1, which is a block diagram illustrating the components of a fluid metering apparatus according to a preferred embodiment of the present invention in association with a fuel cell system. The fluid metering apparatus in the preferred embodiment is implemented as a metering device 3 mounted to a fuel container 2 of a fuel cell 1 and the metering device 3 is configured in the fuel container 2 to detect the physical property of the fuel stored in the fuel container 2. The fuel cell 1 possesses a catalyst to perform electrochemical reaction with the hydrogen-rich fuel and oxygen fuel and acts as an energy converter to convert chemical energy to electrical energy output. The fuel container 2 stores the fuel required by the fuel cell 1 for carrying out the electrochemical reaction, and provides delivering means for supplying the fuel to the fuel cell 1. Moreover, the metering device 3 is employed to measure physical characteristics of the fuel and provides electrical metering means and data processing means. The electrical metering means is used for detecting the electrical characteristics resulting from physical change of the fluid fuel in the container 2. The data processing means is used for converting information relating to the electrical characteristics, which have been detected by the electrical type metering means, into the physical characteristics of the fuel.
The data processing means includes an operation chip, a memory chip and a connecting circuit.
Please refer to FIG. 2, which is a perspective view illustrating the preferred embodiment of a fluid metering apparatus according to the present invention. The metering device 3 is configured in the fuel container 2 and the fuel container 2 is a case with a hollow part 21 and the hollow part 21 is connected to a fuel inlet 22 and a fuel outlet 23 for respectively inputting and outputting the fluid fuel. The metering device 3 is placed in the fuel container 2. The electrical type metering means includes a capacitance type measuring component 31 and the data processing means has a processor 32 so that the physical characteristics of the fuel in the container 2 can be detected with the electrical type metering means and then processed with the data processing means. For example, the physical characteristics of the fuel may be the liquid level, the density, the concentration and other properties. A capacitance value of the capacitance type measuring component 31 is calculated with the data processing means so that a physical quantity for one of the physical characteristics corresponding to the capacitance value can be obtained. Furthermore, the quantity relation or function relation between the capacitance value and the physical quantity is stored in the processor 32 so that the physical quantity corresponding to the capacitance value can be obtained through relationship between the capacitance value and the physical quantity and operation of the processor 32. Meanwhile, the processor 32 is capable of performing the ordinary data transmission and achieving effectiveness of the conventional data processor.
The capacitance type measuring component 3 i can be replaced with a micro strip line such that message relating to the physical characteristics of the fuel can be received by way of measuring electrical signal of the strip line. Further, the measured electrical signal of the strip line can be equivalent capacitance value, equivalent inductance value, impedance value or combination of the preceding electrical signals of the strip line component.
Please refer to FIGS. 3, 4 and 5, which are respectively a side view illustrating the preferred embodiment of a fluid metering apparatus according to the present invention, an enlarged diagram illustrating the components configured therein, and a cross sectional diagram illustrating the preferred embodiment thereof. As shown in FIG. 3, the capacitance measuring component 31 of the electrical metering means of the metering device 3 is vertically extended along the direction of depth of the hollow part 21 of the fuel container 2. As shown in FIG. 4, the capacitance type measuring component 31 can be a fork-shaped capacitance component 311 which includes a first capacitance portion 311a and a second capacitance portion 311b. The first capacitance portion 311a and the second capacitance portion 311b respectively have a plurality of parallel fork-shaped strip lines extending laterally and alternately in the horizontal direction to induce an electrical capacitance effect between the first capacitance portion 311a and the second capacitance portion 311b. As shown in FIG. 5, the capacitance effect between the first capacitance portion 311a and the second capacitance portion 311b is influenced by the dielectric in the hollow part 21 of the container 2. For example, when the liquid level of the fuel 24 in the hollow part 21 of the container 2 lowers to a height h, it results in change of the capacitance value of the fork-shaped capacitance component 311 due to proportion of the air dielectric ε0 to the fuel dielectric ε0εr changing. Accordingly, the capacitance value corresponding to the fork-shaped capacitance component 311 changes too. Hence, it is achievable to obtain the corresponding relationship of the capacitance value and the height h through recordation of experimentation, theory or experiential formula and such corresponding relationship could be stored in the processor 32. Thus, the capacitance value of the fork-shaped capacitance component 311 can be converted into the information regarding the liquid level of the fuel 24 when the capacitance value is fed back to the data processing means.
Please refer to FIG. 6, which is an enlarged side view illustrating the components configured in a fluid metering device according to another preferred embodiment of the present invention. In the preceding metering device 3, the electrical metering means, which extends along depth of the hollow part 21 vertically, has several capacitance measuring components 33. Specifically, the capacitance measuring components 33 are fork-shaped capacitance components and include a first capacitance measuring component 33a, a second capacitance measuring component 33b and a third capacitance measuring component 33c. The capacitance measuring components 33 are capable of providing the capacitance effect respectively. Similarly, it can be seen in FIG. 5 that the capacitance effect of the respective capacitance measuring component 33 is influenced with the dielectric in the hollow part 21 of the container 2. For example, when the liquid level of the fuel 24 in the hollow part 21 of the container 2 is lowered to a height h, the capacitance values corresponding to the first, the second and the third capacitance components 33a, 33b and 33c are changed due to proportion of the air dielectric ε0 and the fuel dielectric ε0εr changing. Accordingly, the capacitance value of the respective capacitance measuring component 33 can be converted into the information regarding the liquid level of the fuel 24 when the capacitance value of the respective capacitance measuring component 33 is fed back to the data processing means.
As the preceding embodiment shown in FIG. 3, the length of the capacitance measuring component 31 extends along with the height of the hollow part 21 in the container 2 so that the capacitance measuring component 31 is able to obtain the electrical information corresponding to the liquid level of the fuel. The measured range of height designed for the capacitance measuring component 31 is that the user or the designer is interested in instead of the height of the hollow part 21. Furthermore, in the embodiment as shown in FIG. 6, the capacitance measuring components 33 are arranged to correspond to different elevations in the hollow parts 21 of the container 2. Accordingly, the capacitance measuring component 31 illustrated in FIG. 3 is capable of measuring the liquid level of the fuel in a large range of height, while the capacitance measuring components 33 as shown in FIG. 6 are capable of measuring the liquid level of the fuel for local ranges of the liquid fuel level. Alternatively, the liquid level of the fluid fuel can be divided into several intervals with switches and the capacitance measuring components 33 correspond to the intervals respectively such that it can be determined if the corresponding interval has the fuel for the liquid level of the fuel being determined as well.
Please refer to FIG. 7, which is an enlarged side view illustrating the components configured in a fluid metering apparatus according to a further preferred embodiment of the present invention. In this embodiment, the capacitance measuring component 31 of the electrical metering means in the preceding metering device 3 extends along the hollow part 21 of the container 2 horizontally and is configured at the bottom of the hollow part 21 so that the capacitance effect of the capacitance measuring component 31 is influenced with the dielectric in the hollow part 21. For example, when the physical characteristic with regard to the fuel concentration in the hollow part 21 of the container 2 is changed, the dielectric εr of the fuel would be changed correspondingly. As a result, the capacitance value corresponding to the capacitance measuring component 31 changes as well. Accordingly, the relationship between the capacitance value and the fuel concentration can be obtained by way of experimentation, theory or experiential formula. Further, such relationship can be stored in the processor 32 such that the capacitance value of the capacitance measuring component 31 is capable of being converted into the information of the concentration of the fuel 24 when the capacitance value of the capacitance measuring component 31 is fed back to the data processing means.
Please refer to FIG. 8, which is an enlarged side view illustrating the components configured in a fluid metering apparatus shown in FIG. 7. When the liquid level becomes lower due to the fuel 24 in the hollow part 21 of the container 2 keeping decreasing and it makes the air dielectric ε0 dominative, it can be learned from the electrical information obtained by the capacitance measuring component 31 of the metering device 3 that the liquid level of the fuel 24 is excessively low. In other words, it is determined from the data processing means that the fuel is almost exhausted.
Please refer to FIG. 9, which is an enlarged side view illustrating the components configured in a fluid metering apparatus according to still a further preferred embodiment of the present invention. In this embodiment, the electrical metering means of the metering device 3 includes several capacitance measuring components 34 and the capacitance measuring components 34 further includes a first capacitance measuring component 34a, a second capacitance measuring component 34b and a third capacitance measuring component 34c. The capacitance measuring components 34 provide a capacitance effect respectively. As shown in FIG. 9, the second capacitance component 34b has the specimen fuel 34d sealed therein and the specimen fuel 34d is identical with those of the fuel 24 stored in the hollow part 21 of the container 2. Accordingly, even though the physical characteristics of the fuel 24 in the chamber 21 of the container 2 are changed, the specimen fuel 34d sealed in the second capacitance measuring component 34b still maintains at the initial state. Hence, the capacitance value measured with the second capacitance measuring component 34b is capable of being regarded as a reference capacitance value for the data processing means determining the changes of the physical characteristics of the fuel 24 in the hollow pars 21 of the container 2.
Moreover, although change of the temperature of the fuel 24 in hollow part 21 of the container 2 may influence the specimen fuel 34d sealed in the second capacitance measuring component 34b, the side effect influenced with temperature factor can be taken away from the obtained reference capacitance value properly.
While the preferred embodiment of the invention has been disclosed above, it is not intended to restrict the scope of the invention. Therefore, any modification or variation under the spirit of the invention would still be in the scope of the present invention.
Patent Application
20080120046
