Method and system for tank refilling

• US 9,212,783 B2
• Filed: 03/15/2013
• Issued: 12/15/2015
• 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: Mathison, Steven
• Primary Examiner(s): Maust, Timothy L
• Application Number:
  US13/843,537
• Publication Number:
  US 20130269828A1
• Time in Patent Office: 1,005 Days
• Field of Search: 141/2, 141/4, 141/11, 141/82, 141/94, 141/95
• US Class Current: 1/1
• 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 refuelling 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 an improved 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, the method comprising:

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

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

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

calculating for the tank a composite heat capacity value MC corresponding to heat transferred to the tank, a tank assembly, connection components and the initial mass of gas within the tank gas, while filling the tank;

determining a target pressure P_target through T_CSinit that is predicted to produce a target state of charge 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 calculating the MC 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 determining the fill time 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; and

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

wherein the calculating the MC comprises calculating a composite heat capacity value MC according to the equation

4. The method of filling a compressed gas tank according to claim 3, 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 calculating the MC comprises:

calculating a composite heat capacity value MC according to the equation

6. The method of filling a compressed gas tank according to claim 1, wherein determining the target pressure P_target 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; and

calculating an adiabatic internal energy U_adiabatic, wherein U_adiabatic incorporates an adjustment for heat added by connection components, Q_connector; and

calculating an adiabatic temperature T_adiabatic,

wherein the calculating the MC comprises calculating a composite heat capacity value MC according to the equation

7. The method of filling a compressed gas tank according to claim 4, wherein determining the values C, A, g, k and j for the tank 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, the method comprising:

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

determining a projected fill time through 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;

calculating for the tank a composite heat capacity value MC corresponding to heat transferred to the tank, a tank assembly, connection components and the initial mass of gas within the tank gas, while filling the tank;

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

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