Method and system for tank refilling using active fueling speed control

Patent metadata

Field	Value
Publication number	US-9347614-B2
Application number	US-201414300229-A
Country	US
Kind code	B2
Filing date	Jun 9, 2014
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 );
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.

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

RR
=

P
final

-
P

t
final

⁡

(

P
final

-

P
initial

P
final

-

P
min

)

-
t

wherein RR is the pressure ramp rate, P is a current pressure of gas measured at a nozzle of the dispenser, P initial is the initial measured pressure of gas in the tank before the fill commenced, P min is the pressure associated with the minimum mass average enthalpy, t final is the fill time, the P final is the pressure calculated to produce a state of charge of 100% within the compressed gas tank, and t is the time elapsed since the fill commenced.

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.

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

MAE
=

α
+
k
+

l
MAT

+

m

MAT
2

+

n

MAT
3

+

p

MAT
4

+

q

MAT
5

+

r

t
fin

+

s

t
fin
2

+

v

Assignees

• Honda Motor Co Ltd

Inventors

• Mathison Steve

Classifications

• F17C2250/0443

  Flow or movement of content · CPC title

• F17C2221/012

  Hydrogen · CPC title

• F17C2260/026

  by calculation · CPC title

• F17C2203/0624

  with four or more layers · CPC title

• F17C2260/023

  Avoiding overheating · CPC title