Method and System for Tank Refilling

• US 20110259469A1
• Filed: 12/31/2010
• Published: 10/27/2011
• Est. Priority Date: 04/21/2010
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: HARTY, Ryan, Mathison, Steve
• Granted Patent: US 8,783,303 B2
• Time in Patent Office: Days
• US Class Current: 141/4
• CPC Class Codes: F17C 13/023 having the mass as the parameter
• CPC Class Codes: F17C 13/025 having the pressure as the parameter
• CPC Class Codes: F17C 13/026 having the temperature as the parameter
• CPC Class Codes: F17C 2201/0109 with exteriorly curved end-piece
• CPC Class Codes: F17C 2201/054 medium (>1 m3)
• CPC Class Codes: F17C 2203/0604 Liners
• CPC Class Codes: F17C 2203/0619 with two layers
• CPC Class Codes: F17C 2203/0624 with four or more layers
• CPC Class Codes: F17C 2221/012 Hydrogen
• CPC Class Codes: F17C 2221/033 Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
• CPC Class Codes: F17C 2223/0123 gaseous, e.g. CNG, GNC
• CPC Class Codes: F17C 2223/0153 Liquefied gas, e.g. LPG, GPL
• CPC Class Codes: F17C 2223/0161 cryogenic, e.g. LNG, GNL, PLNG
• CPC Class Codes: F17C 2223/036 Very high pressure (>80 bar)
• CPC Class Codes: F17C 2225/0123 gaseous, e.g. CNG, GNC
• CPC Class Codes: F17C 2225/036 Very high pressure, i.e. above 80 bars
• CPC Class Codes: F17C 2250/043 Pressure
• CPC Class Codes: F17C 2250/0439 Temperature
• CPC Class Codes: F17C 2250/0443 Flow or movement of content
• CPC Class Codes: F17C 2250/0491 Parameters measured at or inside the vessel
• CPC Class Codes: F17C 2250/0495 : the indicated parameter is a converted measured parameter
• CPC Class Codes: F17C 2250/0631 : Temperature
• CPC Class Codes: F17C 2250/0694 : with calculations
• CPC Class Codes: F17C 2260/022 : Avoiding overfilling
• CPC Class Codes: F17C 2260/023 : Avoiding overheating
• CPC Class Codes: F17C 2260/025 : Reducing transfer time
• CPC Class Codes: F17C 2260/026 : by calculation
• CPC Class Codes: F17C 2265/065 : for refueling vehicle fuel tanks
• CPC Class Codes: F17C 2270/0139 : Fuel stations
• CPC Class Codes: F17C 2270/0168 : by vehicles
• CPC Class Codes: F17C 2270/0176 : Buses
• CPC Class Codes: F17C 5/007 : for individual gas tanks or containers, e.g. in vehicles filling with liquid fuel not under pressure, B60S5/02, B67D7/00
• CPC Class Codes: F17C 5/06 : for filling with compressed gases
• CPC Class Codes: Y02E 60/32 : Hydrogen storage

Abstract

Disclosed is a simple, analytical method that can be utilized by hydrogen filling stations for directly and accurately calculating the end-of-fill temperature in a hydrogen tank that, in turn, allows for improvements in the fill quantity while tending to reduce refueling time. The calculations involve calculation of a composite heat capacity value, MC, from a set of thermodynamic parameters drawn from both the tank system receiving the gas and the station supplying the gas. These thermodynamic parameters are utilized in a series of simple analytical equations to define a multi-step process by which target fill times, final temperatures and final pressures can be determined. The parameters can be communicated to the station directly from the vehicle or retrieved from a database accessible by the station. Because the method is based on direct measurements of actual thermodynamic conditions and quantified thermodynamic behavior, significantly improved tank filling results can be achieved.

Claims

1. A method of filling a compressed gas tank comprising:

calculating a hot soak initial temperature T_HSinit for an initial mass of gas within the tank;

determining a projected fill time using T_HSinit that is predicted to produce a gas final temperature T_final no greater than a target temperature T;

calculating a cold soak initial temperature T_CSinit for an initial mass of gas within the tank;

determining a target pressure P_target using T_CSinit that is predicted to produce a state of charge of 100% within the tank; and

delivering gas to the tank at a pressure ramp rate that will achieve P_target at the projected fill time.

2. The method of filling a compressed gas tank according to claim 1, wherein:

the step of determining the fill time further comprises

calculating a composite heat capacity value MC according to at least one of the equations

3. The method of filling a compressed gas tank according to claim 1, wherein:

the step of determining the fill time further comprises

calculating an initial mass m_init;

calculating an additional mass m_add necessary to achieve the state of charge of 100% within the tank;

calculating the initial internal energy U_initial;

estimating the average enthalpy h_average to be delivered to the tank with the additional mass;

calculating an adiabatic internal energy U_adiabatic and an adiabatic temperature T_adiabatic;

calculating a composite heat capacity value MC according to at least one of the equations

4. The method of filling a compressed gas tank according to claim 3, further comprising:

determining the values C, A, g, k and j for the tank.

5. The method of filling a compressed gas tank according to claim 1, wherein:

the step of determining the target pressure P_target further comprises

calculating a composite heat capacity value MC according to at least one of the equations

6. The method of filling a compressed gas tank according to claim 1, wherein:

the step of determining the target pressure P_target further comprises

calculating a cold initial mass m_initC;

calculating an additional mass m_add necessary to achieve the state of charge of 100% within the tank;

calculating the initial internal energy U_initial;

estimating the average enthalpy h_average to be delivered to the tank with the additional mass;

calculating an adiabatic internal energy U_adiabatic and an adiabatic temperature T_adiabatic; and

calculating a composite heat capacity value MC according to at least one of the equations

7. The method of filling a compressed gas tank according to claim 4, wherein:

the step of determining the values C, A, g, k and j for the tank further comprises

performing a plurality of test fills of the tank to a state of charge of 100% at a target fill time, wherein the test fills encompass a plurality of initial fill pressures and a plurality of pre-cooling temperatures;

calculating an end-of-fill MC for each test fill according to the equation

8. The method of filling a compressed gas tank according to claim 7, wherein:

a first initial pressure represents a state of charge of less than 10% within the tank; and

a first pre-cooling temperature is an ambient temperature.

9. The method of filling a compressed gas tank according to claim 8, wherein:

a second initial pressure represents a state of charge of about 50% within the tank; and

a second pre-cooling temperature is less than 0°

C.

10. The method of filling a compressed gas tank according to claim 7, wherein:

a first initial pressure is 2 MPa and a second initial pressure represents a state of charge of at least about 50% within the tank; and

a first pre-cooling temperature is an ambient temperature and a second pre-cooling temperature is −

20°

C.

11. A method of refueling a hydrogen tank on a hydrogen powered vehicle comprising:

calculating a hot soak initial temperature T_HSinit for an initial mass of gas within the tank;

determining a projected fill time using T_HSinit that is predicted to produce a final hydrogen temperature T_final no greater than a target temperature T;

calculating a cold soak initial temperature T_CSinit for an initial mass of gas within the tank;

determining a target pressure P_target using T_CSinit that is predicted to produce a state of charge of 100%; and

delivering gas to the tank at a pressure ramp rate that will achieve P_target at the projected fill time.

12. A method of operating a hydrogen gas filling station comprising:

obtaining a first set of parametric data corresponding to a hydrogen powered vehicle;

obtaining a second set of parametric data corresponding to station capabilities;

obtaining a third set of parametric data corresponding to a refueling ambient;

calculating a MC value based on the parametric data obtained; and

determining a projected fill time that is predicted to produce a gas final temperature T_final no greater than a target temperature T and achieve a state of charge of 100% within the tank according to Equation [B]

13. The method of operating a hydrogen gas filling station according to claim 12, wherein:

the first set of parametric data is obtained directly from the hydrogen powered vehicle using a communication protocol selected from a group consisting of RFID, HVAS and IRDA.

14. The method of operating a hydrogen gas filling station according to claim 12, wherein:

the first set of parametric data is obtained by identifying the hydrogen powered vehicle and accessing a parametric database maintained outside the vehicle.

15. The method of operating a hydrogen gas filling station according to claim 12, wherein:

the first set of parametric data is assigned default values and

determining an adjusted final target density sufficient to achieve the P_target at the T_final.

16. The method of operating a hydrogen gas filling station according to claim 12, wherein:

the first set of parametric data includes at least one parameter selected from a group consisting of nominal working pressure, tank volume, refueling history, time stamp of last refueling, trip odometer value, initial hydrogen mass, initial gas temperature, maximum hot soak temperature, maximum cold soak temperature, maximum defueling rate and maximum fueling rate.

17. The method of operating a hydrogen gas filling station according to claim 12, further comprising:

maintaining first and second hydrogen fill assemblies, the first hydrogen fill assembly operating at a first pre-cooling temperature and the second hydrogen assembly operating at a second pre-cooling temperature, the first and second pre-cooling temperatures not being equal;

analyzing the first set of parametric data; and

directing the hydrogen powered vehicle to the hydrogen fill assembly that can more efficiently provide a state of charge of 100%.

18. The method of operating a hydrogen gas filling station according to claim 12, further comprising:

calculating a target pre-cooling temperature sufficient to achieve a 3-minute fueling time using parametric information selected from a data set consisting of vehicle fueling history, tank volume, lowest historical initial state-of-charge percent, lowest historical tank MC value, and ambient temperature;

setting and maintaining a hydrogen fill assembly at the target pre-cooling temperature for the duration of a vehicle refueling operation.

19. The method of operating a hydrogen gas filling station according to claim 12, further comprising:

predicting a defueled system temperature for a combined system heat mass;

setting T_{FinalDefuelCold}; and

initiating refueling using T_{FinalDefuelCold}.

20. The method of operating a hydrogen gas fill station according to claim 12, further comprising:

obtaining a first subset of the first set of parametric data, the first subset corresponding to parametric data associated with a first hydrogen tank onboard the hydrogen powered vehicle;

obtaining a second subset of the first set of parametric data, the second subset corresponding to parametric data associated with a second hydrogen tank onboard the hydrogen powered vehicle;

calculating T_final1 using the first subset of parametric data and T_final2 using the second subset of parametric data;

using the greater of T_final1 and T_final2 to t determine a target fueling speed; and

using the lesser of T_final1 and T_{final2 determine Ptarget}.

21. The method of operating a hydrogen gas fill station according to claim 12, further comprising:

initiating a hydrogen gas fill;

adjusting the second set of parametric data during the hydrogen gas fill to reflect measured station performance;

adjusting the MC value during the hydrogen gas fill to reflect variations in the first set of parametric data and measured fill performance data;

calculating an adjusted fill time and P_target to reflect adjustments in the second set of parametric data and MC value; and

using the adjusted fill time to control the fill speed and end of fill conditions.

22. The method of operating a hydrogen gas fill station according to claim 17, wherein:

the more efficient hydrogen fill assembly provides a benefit selected from a group consisting of reduced fueling time, higher state-of-charge percent, increased pre-cooling temperature, reduced energy consumption and combinations thereof.

23. The method of operating a hydrogen gas filling station according to claim 12, the step of obtaining a first set of parametric data corresponding to a hydrogen powered vehicle further comprising:

retrieving refueling time stamp data for the hydrogen powered vehicle.

24. The method of operating a hydrogen gas filling station according to claim 23, wherein:

the refueling time stamp data is retrieved from a HVAS RFID tag associated with the hydrogen powered vehicle.

25. The method of operating a hydrogen gas filling station according to claim 23, wherein:

determining an elapsed time from the refueling time stamp data; and

adjusting fueling speed to allow for a higher refueling speed for a longer elapsed time.