Method and system for tank refilling using active fueling speed control

• US 9,347,614 B2
• Filed: 06/09/2014
• Issued: 05/24/2016
• 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, Steve
• Primary Examiner(s): NIESZ, JASON KAROL
• Application Number:
  US14/300,229
• Publication Number:
  US 20140290790A1
• Time in Patent Office: 715 Days
• 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 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 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, comprising:

determining a fill time (t_final) predicted to produce a gas final temperature (T_final);

determining a final pressure (P_final) calculated to produce a state of charge of 100% within the compressed gas tank;

delivering gas to the compressed gas tank at a pressure ramp rate (RR) that achieves the final pressure (P_final) at a conclusion of the fill time (t_final), wherein the gas is delivered to the compressed gas tank using a dispenser;

calculating a mass average pre-cooling temperature (MAT) of the gas;

calculating an estimated end of fill mass average enthalpy of the gas dispensed to the tank based on at least the mass average pre-cooling temperature (MAT); and

calculating the fill time (t_final) based on the estimated end of fill mass average enthalpy.

7. The method according to claim 1, wherein the estimated end of fill mass average enthalpy is calculated based on at least the mass average pre-cooling temperature (MAT) and an adjustment factor (α

) that accounts for variability in the pressure ramp rate (RR).

8. The method according to claim 1, wherein the estimated end of fill mass average enthalpy is calculated according to the enthalpy map equation

9. The method according to claim 1, wherein calculating the fill time (t_final) comprises:

iteratively calculating an estimation of the fill time (t_fin) until the estimation of the fill time (t_fin) is less than a predetermined value of the estimation of the fill time t_fin, and an absolute value of an MC difference (MC_diff) is less than a predetermined value of the MC difference (MC_diff), where the MC difference (MC_diff) is the difference between a required MC (MC_req) for the tank in hot soak conditions and an actual MC (MC) calculated for the tank in hot soak conditions,

wherein the actual MC (MC) is a composite heat capacity value of the gas in the tank determined according to the equation;

10. The method according to claim 1, wherein, the gas tank is a hydrogen vehicle gas tank.

11. The method according to claim 1, further comprising:

stopping the delivery of gas to the gas tank when any one of the following occurs;

a communication density of gas (ρ

_SOC-comm) in the gas tank is greater than a communication density limit (ρ

_SOC-comm-end);

an MC density of gas (ρ

_SOC-MC) in the gas tank is greater than an MC density of gas limit (ρ

_SOC-MC-end);

the MC density of hydrogen gas (ρ

_SOC-MC) in the gas tank is greater than an MC non-communication density of gas limit (ρ

_{SOC-MC-end-non-comm});

or

a current pressure of gas (P) measured at a nozzle of the dispenser is greater than or equal to a gas tank pressure limit (P_max).

2. A method of filling a compressed gas tank, comprising:

determining a fill time (t_final) predicted to produce a gas final temperature (T_final);

determining a final pressure (P_final) calculated to produce a state of charge of 100% within the compressed gas tank;

delivering gas to compressed gas tank at a pressure ramp rate (RR) that achieves the final pressure (P_final) at a conclusion of the fill time (t_final), wherein the gas is delivered to the compressed gas tank using a dispenser;

continuously calculating a mass average pre-cooling temperature (MAT) of the gas;

continuously calculating an estimated end of fill mass average enthalpy of the gas dispensed to the tank based on at least the mass average pre-cooling temperature (MAT); and

continuously calculating the fill time (t_final) based on the estimated end of fill mass average enthalpy of the gas dispensed to the tank.

3. The method according to claim 2, wherein, while delivering gas to the gas tank, the method comprises:

continuously calculating the pressure ramp rate (RR) that achieves the final pressure (P_final) based on the fill time (t_final);

continuously determining a fueling speed based on the calculated pressure ramp rate (RR); and

continuously adjusting the fueling speed to the determined fueling speed while delivering gas to the gas tank.

4. The method according to claim 3, wherein the pressure ramp rate (RR) is continuously calculated according to the equation

5. The method according to claim 2, wherein calculating the mass average pre-cooling temperature (MAT) includes:

setting the mass average pre-cooling temperature (MAT) to equal a predetermined expected mass average pre-cooling temperature (MAT_expected), when less than a predetermined amount of time has elapsed since a beginning of the fill;

setting the mass average pre-cooling temperature (MAT) equal to a mass average pre-cooling temperature iteratively calculated from the predetermined time following the beginning of the fill until the current time, when the predetermined amount of time has elapsed since the beginning of the fill and a pressure (P) of gas measured at a nozzle of the dispenser is less than a predetermined pressure; and

setting the mass average pre-cooling temperature (MAT) equal to a transitional weighted average of a mass average pre-cooling temperature iteratively calculated since the beginning of the fill until the current time and the mass average pre-cooling temperature iteratively calculated from the predetermined time following the beginning of the fill until the current time, when the predetermined amount of time has elapsed since the beginning of the fill and the pressure of gas (P) measured at the nozzle of the dispenser is greater than or equal to the predetermined pressure.

6. The method according to claim 5, wherein calculating the transitional weighted average of the mass average pre-cooling temperature includes, increasing a weighting factor on the mass average pre-cooling temperature iteratively calculated since the beginning of the fill until the current time, and decreasing a weighting factor on the mass average pre-cooling temperature iteratively calculated from the predetermined time following the beginning of the fill until the current time, as the pressure of the gas in the gas tank increases.

19. The method according to claim 2, wherein the gas tank is a hydrogen vehicle gas tank.

20. The method according to claim 2, further comprising:

stopping the delivery of gas to the as tank when any one of the following occurs;

a communication density of gas (ρ

SOC-comm) in the gas tank is greater than a communication density limit (ρ

SOC-comm-end);

an MC density of gas (ρ

SOC-MC) in the gas tank is grater than an MC density of gas limit (ρ

SOC-MC-end);

the MC density of hydrogen gas (ρ

SOC-MC) in the gas tank is greater than an MC non-communication density of gas limit (ρ

SOC-MC-end-non-comm);

or

a current pressure of gas (P) measured at a nozzle of the dispenser is greater than or equal to a gas tank pressure limit (Pmax).

12. A controller configured to control a hydrogen filling station, the controller comprising:

an input receiver configured to continuously receive measured values of a pressure (P), a temperature, and a flow rate of hydrogen dispensed to a gas tank from a temperature sensor, a pressure sensor, and a mass flow meter provided in a dispenser of the hydrogen gas filling station; and

a fueling speed controller configured to;

calculate a mass average pre-cooling temperature (MAT) of the hydrogen gas;

calculate an estimated end of fill mass average enthalpy of the gas dispensed to the tank based on at least the mass average pre-cooling temperature (MAT) while the hydrogen is being dispensed to the gas tank by the dispenser of the hydrogen filling station;

calculate a fill time (t_final) based on the estimated end of fill mass average enthalpy while the hydrogen is being dispensed to the gas tank by the dispenser of the hydrogen filling station;

calculate a pressure ramp rate (RR) that achieves a final pressure (P_final) based on the fill time (t_final) while the hydrogen is being dispensed to the gas tank by the dispenser of the hydrogen filling station;

determine a fueling speed based on the pressure ramp rate (RR) while the hydrogen is being dispensed to the gas tank by the dispenser of the hydrogen filling station; and

control the dispenser of the hydrogen filling station to adjust the fueling speed while the hydrogen is being dispensed to the gas tank by the dispenser of the hydrogen filling station.

13. The controller according to claim 12, wherein the fueling speed controller is configured to:

set the mass average pre-cooling temperature (MAT) to equal a predetermined expected mass average pre-cooling temperature (MAT_expected), when less than a predetermined amount of time has elapsed since a beginning of the fill;

set the mass average pre-cooling temperature (MAT) equal to a mass average pre-cooling temperature iteratively calculated from the predetermined time following the beginning of the fill until the current time, when the predetermined amount of time has elapsed since the beginning of the fill and the pressure (P) of gas measured at a nozzle of the dispenser is less than a predetermined pressure; and

calculate the mass average pre-cooling temperature (MAT) by setting the mass average pre-cooling temperature (MAT) equal to a transitional weighted average of a mass average pre-cooling temperature iteratively calculated since the beginning of the fill until the current time and the mass average pre-cooling temperature iteratively calculated from the predetermined time following the beginning of the fill until the current time, when the predetermined amount of time has elapsed since the beginning of the fill and the pressure (P) of gas measured at the nozzle of the dispenser is greater than or equal to the predetermined pressure.

14. The controller according to claim 13, wherein calculating the transitional weighted average of the mass average pre-cooling temperature includes increasing a weighting factor on the mass average pre-cooling temperature iteratively calculated since the beginning of the fill until the current time and decreasing a weighting factor on the mass average pre-cooling temperature iteratively calculated from the predetermined time following the beginning of the fill until the current time as the pressure of the gas in the gas tank increases.

15. The controller according to claim 12, wherein the fueling speed controller is configured to calculate the estimated end of fill mass average enthalpy according to the enthalpy map equation:

16. The controller according to claim 12, wherein the fueling speed controller is configured to calculate the fill time t_final by:

iteratively calculating an estimation of the fill time (t_fin) until the estimation of the fill time t_fin is less than a predetermined value of the estimation of the fill time (t_fin), and an absolute value of an MC difference (MC_diff) is less than a predetermined value of the MC difference (MC_diff), where the MC difference (MC_diff) is the difference between a required MC (MC_req) for the tank in hot soak conditions and an actual MC (MC) calculated for the tank in hot soak conditions,

wherein the actual MC (MC) is a composite heat capacity value of the gas in the tank determined according to the equation;

17. The controller according to claim 12, wherein the fueling speed controller is configured to continuously calculate the pressure ramp rate (RR) according to the equation

18. The controller according to claim 12, wherein the fueling speed controller is further configured to:

stop the delivery of hydrogen gas to the compressed gas tank when any one of the following occur;

a communication density of hydrogen gas (ρ

_SOC-comm) in the gas tank is greater than a communication density limit (ρ

_SOC-comm-end);

an MC density of hydrogen gas (ρ

_SOC-MC) in the gas tank is greater than an MC density of gas limit (ρ

_SOC-MC-end);

the MC density of hydrogen gas (ρ

_SOC-MC) in the gas tank is greater than an MC non-communication density of gas limit (ρ

_{SOC-MC-end-non-comm}), or

the current pressure (P) of hydrogen gas measured at a nozzle of the dispenser is greater than or equal to a gas tank pressure limit (P_max).