METHOD AND DEVICE FOR DETECTING AN AMOUNT OF GAS IN A CALIBRATION-CAPABLE MANNER

Abstract

The invention relates to a method and to a device for determining an amount of gaseous fuel, which during a refueling process at a gas station has been transferred into a storage tank via a gas pump (3) and a filling hose (4) connected thereto, wherein in the gas pump (3) of the gas station, a flow meter (F) is provided, which during the filling of the storage tank detects the amount of fuel dispensed. Once the filling is completed, the filling hose (4) is depressurized, and the amount of fuel, which has not been transferred into the storage tank due to the depressurization, is detected, and this amount is subtracted from the amount detected by the flow meter (F).

Claims

1. A method for determining an amount of gaseous fuel, which during a refueling process at a filling station has been transferred into a storage tank by means of a fuel dispenser (3) and a filling hose (4) connected thereto, wherein a flow meter (F) is provided in the fuel dispenser (3) of the filling station and determines the amount of fuel dispensed during the filling of the storage tank, and wherein the filling hose (4) is depressurized once the filling process is completed, characterized in that the amount of fuel, which has not been transferred into the storage tank due to the depressurization, is determined and this amount is subtracted from the amount determined by the flow meter (F).

2. The method according to claim 1, characterized in that the amount of fuel in the filling hose (4), which has not been transferred into the storage tank, is determined in that a temperature value (T) and a pressure (p) in the filling hose (4) are respectively determined after the completion of the refueling process and prior to the depressurization in order to determine a density (p) of the fuel in the filling hose (4), in that the volume (V) of the filling hose (4) is known, and in that the dispensed amount (M) of fuel, which has remained in the filling hose (4) after the completion of the refueling process, is thereby determined.

3. The method according to claim 1, characterized in that the amount of fuel in the filling hose (4), which has not been transferred into the storage tank, is determined in that a temperature value (T) in the filling hose (4) is determined after the completion of the refueling process and prior to the depressurization and a pre-adjusted pressure value is used for determining a density (p) of the fuel in the filling hose (4), in that the volume (V) of the filling hose (4) is known, and in that the dispensed amount (M) of fuel, which has remained in the filling hose (4) after the completion of the refueling process, is thereby determined.

4. The method according to claim 1, characterized in that the amount of fuel in the filling hose (4), which has not been transferred into the storage tank, is determined in that a pressure value (D) in the filling hose (4) is determined after the completion of the refueling process and prior to the depressurization and a pre-adjusted temperature value (T) is used for determining a density (p) of the fuel in the filling hose (4), in that the volume (V) of the filling hose (4) is known, and in that the dispensed amount (M) of fuel, which has remained in the filling hose (4) after the completion of the refueling process, is thereby determined.

5. The method according to claim 1, characterized in that the gaseous fuel is preferably hydrogen.

6. The method according to claim 1, characterized in that the flow meter (F) is a Coriolis flow meter or a differential pressure flow meter.

7. The method according to claim 1, characterized in that the pressure in the filling hose (4) lies between 0 and 710 bar, particularly between 350 and 700 bar, during the refueling process.

8. The method according to claim 1, characterized in that the pressure in the filling hose (4) lies between 0 and 2 bar after the depressurization.

9. A device for determining an amount of gaseous fuel dispensed during a refueling process at a filling station, which is installed in a fuel dispenser (3) and connected to a filling hose (4), characterized in that the device comprises a flow meter (F), to which the filling hose (4) is connected, and in that a pipeline with an expansion valve (6) branches off the filling hose (4).

10. The device according to claim 9, characterized in that sensors for pressure and temperature measurements are provided in or on the filling hose.

Description

[0036] The invention is described in greater detail below with reference to the exemplary embodiments that are schematically illustrated in FIG. 1 and FIG. 2.

[0037] FIG. 1 shows a schematic design of a fuel dispenser for gaseous fuel with an expansion valve.

[0038] FIG. 2 shows an alternative schematic design of a fuel dispenser for gaseous fuel.

[0039] FIG. 1 schematically shows the most important components of the fuel dispenser of a filling station for gaseous fuel. The fuel is fed to the fuel dispenser 3 by means of a not-shown pump and/or from a storage tank via a pipe 1. The pipe 1 is provided with corresponding insulation 2. The insulation 2 serves for maintaining the fuel at the desired temperature. The temperature control is realized with methods that are familiar to a person skilled in the art and may take place at different locations in the filling station depending on the method used. The shutoff valve 5 is arranged on the pipeline 1 in the fuel dispenser 3. In the illustrated variation of the invention, the shutoff valve 5 is realized in the form of a pressure regulator. A flow meter F is arranged downstream of the shutoff valve 5 and a junction with an expansion valve 6 is located downstream of the flow meter. The filling hose 4 is realized in the form of a stable pipe within the fuel dispenser and in the form of a flexible hose outside the fuel dispenser and comprises a not-shown refueling coupler. The distances between the shutoff valve 5, the flow meter F and the expansion valve 6 should be chosen as small as possible.

[0040] In order to carry out the refueling process, the filling hose 4 is connected to a receiver tank, which typically consists of a vehicle tank, by means of a refueling coupler. The shutoff valve 5 is opened and gaseous fuel is conveyed into the receiver tank through the flow meter F. In the process, the flow meter F detects the dispensed amount of fuel. The expansion valve 6 is closed. The shutoff valve 5 is closed after the completion of the refueling process. A shutoff valve on the receiver tank is also closed in order to prevent the escape of already dispensed gas from the tank.

[0041] Subsequently, the temperature and the pressure in the filling hose are determined in order to thereby calculate a density, based on which the amount of fuel can be calculated. The expansion valve 6 is opened after the temperature and pressure measurements. The calculated amount is subtracted from the amount determined by the flow meter. The corrected amount is billed. In this way, an exact price for the dispensed fuel is calculated for the customer, as well as for the operator.

[0042] FIG. 2 shows an alternative embodiment. The components are essentially identical and therefore not described anew. This embodiment differs from the exemplary embodiment illustrated in FIG. 1 in that the junction with the expansion valve 6 is located directly downstream of the shutoff valve 5 and the flow meter F is arranged downstream of said junction. Consequently, the fuel remaining in the filling hose flows back through the flow meter F when the expansion valve 6 is opened after the refueling process. Depending on the type of flow meter used, the amount flowing back is either directly subtracted from the previously detected amount or detected separately and subtracted mathematically. This exemplary embodiment likewise ensures that only the actually dispensed amount of fuel is billed.

LIST OF REFERENCE SYMBOLS

[0043] 1 Pipe for fuel [0044] 2 Insulation [0045] 3 Fuel dispenser [0046] 4 Filling hose [0047] 5 Shutoff valve [0048] 6 Expansion valve [0049] F Flow meter