Method and system for tank refilling using active fueling speed control

Patent metadata

Field	Value
Publication number	US-9347612-B2
Application number	US-201313832311-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Apr 21, 2010
Publication date	May 24, 2016
Grant date	May 24, 2016

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.

First claim

The invention claimed is:

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 no greater than a target temperature T;
determining a target pressure P target predicted 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 that achieves the target pressure P target at a conclusion of the determined fill time t final ; and
wherein, while delivering as to the compressed gas tank, the method further comprises:
continuously measuring a pressure and temperature of gas dispensed to the compressed gas tank;
continuously calculating a mass average enthalpy dispensed to the compressed gas tank based on the continuously measured pressure and temperature of the gas dispensed to the compressed gas tank; and
continuously calculating the fill time t final based on the continuously calculated mass average enthalpy.

2. The method according to claim 1 , wherein, while delivering gas to the gas tank, the method comprises:
continuously calculating the pressure ramp rate that achieves the target pressure P target based on the continuously calculated fill time t final ;
continuously determining a fueling speed based on the continuously calculated pressure ramp rate; and
continuously adjusting the fueling speed to the continuously determined fueling speed while delivering gas to the gas tank.

3. The method according to claim 2 , wherein the pressure ramp rate is continuously calculated according to the equation

RR
=

P
target

-

P
current

t
final

⁡

(

P
target

-

P
initial

P
target

-
2

)

-

t
current

wherein RR is the pressure ramp rate, P current is a current pressure, P initial is an initial pressure, and t current is a current time elapsed since a start of filling the compressed gas tank.

4. The method according to claim 1 , wherein calculating the mass average enthalpy includes:
calculating a current value of the mass average enthalpy based on measured values of the pressure and temperature at the time of calculation;
comparing the calculated current value of the mass average enthalpy to a previously calculated value of the mass average enthalpy and a mass average enthalpy threshold value;
if the calculated current value of the mass average enthalpy is less than the previously calculated value of the mass average enthalpy and the mass average enthalpy threshold value, then set the current value of the mass average enthalpy to equal the mass average enthalpy threshold value; and
if the calculated current value of the mass average enthalpy is greater than or equal to at least one of the previously calculated value of the mass average enthalpy and the mass average enthalpy threshold value, then set the current value of the mass average enthalpy to equal the calculated current value of the mass average enthalpy.

5. A method of filling a compressed as tank, comprising:
determining a fill time t final predicted to produce a gas final temperature T final no greater than a target temperature T;
determining a target pressure P target predicted 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 that achieves the target pressure P target at a conclusion of the determined fill time t final ;
wherein calculating the fill time t final comprises:
calculating an initial hot soak temperature T HSinit for an initial mass of gas within the compressed gas tank;
calculating a composite heat capacity value MC according to the equation

MC
=

m
cv

⁢

C
v

⁢

(

T
adiabatic

-

T
Final

)

(

T
Final

-

T
HSinit

)

wherein m cv is a final mass, C v is a specific heat capacity of hydrogen at constant volume, T adiabatic is an adiabatic final gas temperature; and
calculating the fill time t final according to the equation

Δ
⁢

⁢
t

=

-

1
k

⁢

ln
(

1
-

[

MC
-
A
-

Bln
⁢

U
adiabatic

U
initial

g

]

Assignees

• Honda Motor Co Ltd

Inventors

• Mathison Steve

Classifications

• F17C2225/036

  Very high pressure, i.e. above 80 bars · CPC title

• Y02E60/321

  Cross-Sectional Technologies · mapped topic

• F17C2250/0439

  Temperature · CPC title

• F17C2221/033

  Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG · CPC title

• F17C2250/0495

  the indicated parameter is a converted measured parameter · CPC title