Abstract:
A fuel storage vessel includes a valve operatively associated with the storage vessel, a conduit disposed within the vessel and in fluid communication with the valve for delivering a stream of pressurized fuel to the storage vessel and a detector adjacent the conduit for detecting a state of the pressurized fuel in the storage vessel. The detector is positioned outside of the stream of pressurized fuel.

Description:
BACKGROUND 
     1. Field 
     The invention relates to fuel storage systems. 
     2. Discussion 
     Hydrogen fuel cell vehicles may store hydrogen on-board in pressurized storage systems. Certain storage systems and strategies for delivering fuel to these storage systems are known. As an example, United States Patent Publication No. 2007/0000016 to Handa discloses a high pressure fuel depot refilling line operatively interconnected to an on-board vehicle tank having a gas flow circuit. The refuel gas is circulated within the on board tank to absorb the compression heat of refueling and then to an external radiator before being released into the tank. 
     SUMMARY 
     A fuel storage system includes a fuel storage vessel, a valve operatively associated with the vessel and a conduit disposed within the vessel and in fluid communication with the valve for delivering a stream of pressurized fuel to the vessel. The system also includes a detector adjacent the conduit for detecting a state of the pressurized fuel in the vessel. The detector is positioned outside of the stream of pressurized fuel. 
     While example embodiments in accordance with the invention are illustrated and disclosed, such disclosure should not be construed to limit the invention. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view, in partial cross-section, of a portion of a fuel storage system for an automotive vehicle. 
         FIG. 2  is an example plot of time versus temperature for the hydrogen storage system of  FIG. 1 . 
         FIG. 3  is a side view, in partial cross-section, of a portion of another fuel storage system for an automotive vehicle. 
         FIG. 4  is an example plot of time versus temperature and pressure for the fuel storage systems of  FIGS. 1 and 3 . 
     
    
    
     DETAILED DESCRIPTION 
     To minimize refueling times associated with fuel cell vehicles, it may be desirable to quickly fill an on-board fuel storage vessel for the fuel cells. The flow rate at which fuel is provided to the storage vessel influences the time it takes to fill the storage vessel. 
     As known to those of ordinary skill, a temperature of the fuel in the storage vessel during refueling is related to the flow rate (and duration) at which the fuel is provided to the storage vessel. It is also known that, certain storage vessels are rated for certain recommended maximum temperatures. For example, a storage vessel may be designed to provide pressurized storage of a gaseous fuel at maximum storage vessel temperatures less than 85 degrees Celsius. 
     The temperature at which fuel is provided to a storage vessel is typically less than the rated temperature of the storage vessel. The rated temperature of the storage vessel may thus limit the flow rate at which fuel is provided to the storage vessel. 
     During certain refueling operations, the temperature of the fuel inside the storage vessel may exceed the temperature of the storage vessel itself (provided the temperature of the storage vessel itself is less than its temperature rated limit.) For example, if the temperature of the storage vessel is 30 degrees Celsius before a refueling operation, the fuel may be provided to the storage vessel at relatively high flow rates to minimize refueling times and thus yield fuel temperatures inside the storage vessel significantly greater than 30 degrees Celsius. Such refueling strategies typically result in the need to monitor fuel temperature and control flow rate to prevent exceeding the storage vessel rated temperature. 
     Referring now to  FIG. 1 , a pressurized storage system includes a pressurized tank  10  and a valve  12  threadedly engaged with the tank  10 . The valve  12  provides a passageway  14  for hydrogen gas to be provided to the tank  10 . An O-ring  13  provides a seal between the valve  12  and the tank  10 . 
     A moveable element  16 , e.g., plunger, of a solenoid  18  may be positioned by the solenoid  18  to restrict or block the flow of hydrogen gas through the passageway  14 . As illustrated in  FIG. 1 , the moveable element  16  is in the open position, thus allowing hydrogen to flow through the passageway  14 . In the closed position (not shown), the moveable element  16  extends into the passageway  14 . 
     The solenoid  18  receives control signals from a vehicle controller (not shown) via a pair of solenoid control wires  20 . The solenoid control wires  20  pass through a pressure seal  22  and terminate at an electrical connector  24 . The electrical connector  24  is attached with a mating electrical connector  26  of a wiring harness  27  electrically connected with the vehicle controller. 
     A temperature sensor  28  is disposed within the tank  10  and may be attached to the solenoid  18  via a tie-strap  29 . The sensor  28  provides signals indicative of a temperature of the hydrogen within the tank  10  to the vehicle controller via a pair of sensor wires  30 . The sensor wires  30  also pass through the seal  22  within the valve  12  and terminate at the electrical connector  24 . 
     Referring now to  FIGS. 1 and 2 , a temperature of an inner wall of the tank  10  (measured with a temperature sensor not shown) was found to be generally greater than the temperature of the hydrogen (measured with the temperature sensor  28 ) within the tank  10  during refueling at flow rates expected to yield hydrogen temperatures greater than the inner wall temperature. Analysis revealed that the temperature of the hydrogen within the tank  10  was lower than expected because the temperature sensor  28  was positioned in the general path of the hydrogen entering the tank  10  via the passageway  14 . (Hydrogen gas entering the tank  10  was colder than the hydrogen in the tank  10 ). 
     Referring now to  FIG. 3 , an embodiment of a fuel storage system  32  for an automotive fuel cell vehicle (not shown) includes a fuel storage vessel  34 . Fuel, e.g., hydrogen, etc., may be stored in the storage vessel  34 . 
     A valve  36  is threadedly engaged with the storage vessel  34  and provides a passageway  38  for pressurized fuel to be provided to or removed from the storage vessel  34 . A pressure seal  40 , e.g., O-ring, provides a seal between the valve  36  and the storage vessel  34 . In other embodiments, the valve  36  may be spaced away from the storage vessel  34 . In such embodiments, the passageway  38  may be configured to fluidly communicate with the storage vessel  34 . Other arrangements are also possible. 
     A moveable element  42 , e.g., plunger, associated with a solenoid  44  may be positioned by the solenoid  44  to restrict or block the flow of pressurized fuel through the passageway  38 . As illustrated, the moveable element  42  is in the closed position, thus preventing fuel from passing through the passageway  38 . Any suitable technique, however, may be used to control the flow of pressurized fuel through the passageway  38 . 
     The solenoid  44  receives control signals from a vehicle controller (not shown) via a pair of solenoid control wires  46 . The solenoid control wires  46  pass through a pressure seal  48  and terminate at an electrical connector  50 . The electrical connector  50  may be attached with a mating electrical connector  52  of a wiring harness  53  electrically connected with the vehicle controller. 
     A conduit  54 , e.g., flow tube, is threadedly engaged with the valve  34  and fluidly communicates with the passageway  38 . In other embodiments, the conduit  54  may be fixedly attached with the valve  34  or tank  10  in any suitable fashion, e.g., bonded, etc. The conduit  54  extends away from the valve  36  and into the storage vessel  34 . An end  56  of the conduit  54  may provide an inlet to the storage vessel  34  if fuel is being provided to the storage vessel  34 . The end  56  may also provide an outlet from the storage vessel  34  if fuel is being removed from the storage vessel  34 . 
     A sensor  58 , e.g., temperature sensor, pressure sensor, etc., is disposed within the storage vessel  34 . In the embodiment of  FIG. 3 , the sensor  58  is attached to the solenoid  44  with a tie-strap  59  and spaced away from the conduit  54 . In other embodiments, the sensor  58  may be attached with the solenoid  44  and/or conduit  54  in any suitable fashion. In still other embodiments, the sensor  58  may not be attached with the solenoid  44  and/or conduit  54 . Of course, other configurations are also possible. The sensor  58  is positioned such that it is between the valve  36  and the end  56  of the conduit  54 . 
     The sensor  58  provides signals indicative of a measured parameter, e.g., temperature, pressure, etc., associated with fuel within the storage vessel  34  to the vehicle controller (not shown) via a pair of sensor wires  60 . The sensor wires  60  also pass through the seal  48  within the valve  34  and terminate at the electrical connector  50 . 
     Referring now to  FIGS. 1, 3 and 4 , a temperature of hydrogen, as measured by the sensor  28 , within the tank  10  during a portion of refueling was less than a temperature of hydrogen, as measured by the sensor  58 , within the storage vessel  34  (under the substantially same conditions). The pressures within the tank  10  and storage vessel  34  continued to increase during refueling and leveled off once refueling was complete. Because the sensor  58  was positioned away from the general path of the hydrogen entering the storage vessel  34  via the passageway  38 , the temperatures measured by the sensor  58  were more accurate as compared to those measured by the sensor  28 . 
     The inaccurate temperature measurements of the sensor  28  resulted in an over-temperature fill of the tank  10 . That is, the temperature of the hydrogen in the tank  10  exceeded the rated temperature limit of the tank  10  after refueling was complete. This over-temperature fill was due to lower than actual temperature values being input into the refueling strategy. As explained above, certain refueling strategies may set refueling flow rates and refueling duration as a function of the temperature inside the storage vessel. The artificially low temperatures measured by the sensor  28  led to an inappropriate fueling strategy, e.g., higher than required flow rates and longer than required refueling duration, and thus an over-temperature fill as compared to the storage vessel  34 . 
     While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.