System and method for delivering fuel to an aircraft from a vehicle

CROSS-REFERENCE TO RELATED APPLICATION

0001This is a Reissue Application of U.S. Pat. No. 8,708,004, issued Apr. 29, 2014.

0002This patent application claims priority to U.S. patent application Ser. No. 61/242,435, filed Sep. 15, 2009, which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

0003The invention relates to a fuel vehicle that is equipped with a system for delivering fuel to an aircraft, and a method for delivering fuel to an aircraft.

BACKGROUND OF THE INVENTION

0004The invention relates to a fuel vehicle that is equipped with a system for delivering fuel to an aircraft, and a method for delivering fuel to an aircraft. U.S. Pat. Nos. 6,082,392, 6,324,840 and 7,327,045 to Watkins are incorporated herein by reference in their entirety.

SUMMARY OF THE INVENTION

0005A fueling control system for providing fuel from a vehicle to an aircraft, and a method of providing fuel from a fuel vehicle to an aircraft are disclosed herein. The fueling control system includes a pressure transducer for sensing back pressure in a fluid path to a fuel tank of an aircraft, and a digital controller coupled to the pressure transducer for receiving the back pressure in the fluid path and controlling fuel flow in the fluid path to the aircraft. The method includes the steps of sensing back pressure in a fluid path from the aircraft; receiving the sensed back pressure by a digital controller; and controlling fuel flow to the aircraft in the fluid path based on the sensed back pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

0006The foregoing summary as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

0007In the drawings:

0008<figref idref="DRAWINGS">FIG. 1</figref> depicts a schematic illustration of a fuel vehicle having a hose connected to an aircraft to deliver fuel to the aircraft.

0009<figref idref="DRAWINGS">FIG. 2</figref> depicts a schematic illustration of a bulk fuel delivery system according to an exemplary embodiment of the invention.

0010<figref idref="DRAWINGS">FIG. 3</figref> depicts a schematic illustration of a control system for the bulk fuel delivery system of <figref idref="DRAWINGS">FIG. 2</figref>.

0011<figref idref="DRAWINGS">FIG. 4</figref> is a plot of a drop in pressure across a system versus the back pressure sensed at a nozzle fueling an aircraft, in accordance with an embodiment of the present invention.

0012<figref idref="DRAWINGS">FIG. 5</figref> is a flow diagram showing an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

0013In the figures, identical item numbers in different figures refer to identical components.

0014Referring to the drawings, <figref idref="DRAWINGS">FIG. 1</figref> shows a vehicle <b>6</b> having a fuel tank <b>2</b> and a bulk fuel delivery system <b>8</b>. A hose <b>12</b> that is fluidly connected to the delivery system <b>8</b> is connected to the aircraft <b>14</b> for refueling purposes. Fuel flows from the fuel tank <b>2</b> into the bulk fuel delivery system <b>8</b> of the fuel vehicle <b>6</b> and through the hose <b>12</b> for fueling the aircraft <b>14</b>. Details of the bulk fuel delivery system are described in greater detail with reference to <figref idref="DRAWINGS">FIGS. 2-3</figref>.

0015<figref idref="DRAWINGS">FIG. 2</figref> depicts a schematic illustration of a bulk fuel delivery system <b>8</b> of the vehicle of <figref idref="DRAWINGS">FIG. 1</figref> according to a first exemplary embodiment of the invention. The bulk fuel delivery system <b>8</b> includes a fuel tank <b>2</b> for storing fuel that is fluidly connected to a pump <b>24</b> by a fluid line <b>30</b>. Fuel is distributed through the fluid line <b>30</b> by the pump <b>24</b>. The pump <b>24</b> is driven by the vehicle engine <b>26</b> by way of a power take-off (PTO) shaft <b>28</b>, such that power is transferred from the engine <b>26</b> of the vehicle to the pump <b>24</b>. PTO shafts are well-known in the art.

0016A butterfly valve <b>32</b> is connected to fluid line <b>30</b> downstream of pump <b>24</b> for either permitting or preventing passage of fuel through fluid line <b>30</b>. The butterfly valve <b>32</b> is movable between a fully-open position and a fully-closed position. The butterfly valve <b>32</b> is controlled by a deadman control (not shown). The deadman control is connected to a pressurized air source. A pilot valve (not shown) is connected between the deadman control and the pressurized air source to control flow of air to the deadman control.

0017When the pilot valve is maintained in an open position, air is supplied to the deadman control. Upon actuating the deadman control, air is delivered to the pilot valve, thereby opening butterfly valve <b>32</b> to permit flow of fuel through valve <b>32</b>. Alternatively, when the pilot valve is closed, air is not supplied to the deadman control and air is not delivered to valve <b>32</b> even if the operator of system <b>8</b> actuates the deadman control.

0018A fuel filter/separator <b>34</b> is connected to fluid line <b>30</b> for filtering the fuel and removing contaminant particles from the fuel. A check valve <b>36</b> and a globe valve <b>38</b>, also referred to as a fuel-defuel valve <b>38</b>, is fluidly coupled to fluid line <b>30</b> downstream of the fuel filter/separator <b>34</b>. In a ‘fuel’ mode of the fuel-defuel valve <b>38</b>, fuel is transferred from the fuel tank <b>2</b> of the vehicle to the aircraft. In operation fuel that is introduced into port <b>38</b>a of four-way valve <b>38</b> is delivered through port <b>38</b>b of the valve <b>38</b>, through hoses <b>12</b> and/or <b>13</b>, to the aircraft.

0019In a ‘defuel’ mode of the fuel-defuel valve <b>38</b>, fuel is transferred from the aircraft to the fuel tank <b>2</b> of the vehicle. In operation, fuel is distributed through port <b>38</b>a through port <b>38</b>c of valve <b>38</b> and through eductor <b>50</b>. The flow of fuel through eductor <b>50</b> creates suction at port <b>38</b>d, resulting in the siphoning of fuel from the aircraft through hose <b>12</b>, through port <b>38</b>b, through port <b>38</b>d of valve <b>38</b>, through return fluid line <b>31</b>, to fuel tank <b>2</b>. General operation of eductor <b>50</b> and fuel-defuel valve <b>38</b> are known to those skilled in the art.

0020A fuel meter <b>40</b> is fluidly coupled to fluid line <b>30</b> downstream of valve <b>38</b>. The fuel meter <b>40</b> includes a visible counter <b>42</b> that indicates the amount of fuel that flows through fuel meter <b>40</b>. The counter <b>42</b> also converts the flow rate of fuel through the fuel meter <b>40</b> into an electrical signal, which is transmitted to a digital controller <b>22</b>.

0021A pressure transducer <b>20</b> is fluidly coupled to fluid line <b>30</b> downstream of meter <b>40</b>. The pressure transducer <b>20</b> converts fuel pressure from the aircraft (back pressure) into an electrical signal. The pressure transducer <b>20</b> communicates with the digital controller <b>22</b>.

0022The digital controller <b>22</b> processes the fuel back pressure and the flow rate signals transmitted from pressure transducer <b>20</b> and the counter <b>42</b>, respectively, to adjust speed of engine <b>26</b>, as described below. Further details of digital controller <b>22</b> are described with reference to <figref idref="DRAWINGS">FIG. 3</figref>. A digital pressure display <b>27</b> communicates with digital controller <b>22</b> to display fuel pressure to an operator of bulk fuel delivery system <b>8</b>.

0023A hose <b>12</b> and its associated gate valve are fluidly coupled to fluid line <b>30</b>. A nozzle at the end of hose <b>12</b> may be connected to an aircraft (or other vehicle) to zo deliver fuel to a tank within the aircraft (not shown). The nozzle of hose <b>12</b> includes a hose end pressure controller (HEPC) configured to deliver fuel at a maximum pressure of 45 PSI. If the fuel pressure exceeds 45 PSI, the HEPC is configured to close a valve <b>41</b> in the nozzle to prevent the passage of fuel through the nozzle. The HEPC is an optional component of hose <b>12</b>, and may be omitted without departing from the scope or spirit of the invention. A second hose <b>13</b> and its associated gate valve are also fluidly coupled to fluid line <b>30</b>. A nozzle at the end of the hose <b>13</b> may be connected to an aircraft (or other vehicle) to deliver fuel to another tank within the aircraft (not shown).

0024<figref idref="DRAWINGS">FIG. 3</figref> depicts a schematic illustration of a control system <b>60</b> for bulk fuel delivery system <b>8</b> of <figref idref="DRAWINGS">FIG. 2</figref>. The control system <b>60</b> generally includes digital controller <b>22</b>. The digital controller <b>22</b> communicates with pressure transducer <b>20</b>, digital pressure display <b>27</b>, a calibration sensor <b>62</b>, and an ECU (engine control unit) connector <b>64</b>. The digital controller <b>22</b> may communicate on a SAE J1939 datalink. The pressure transducer <b>20</b> senses the fuel back pressure and transmits corresponding electrical signals to digital controller <b>22</b>. The counter <b>42</b> senses the flow rate of the fuel and transmits corresponding electrical signals to digital controller <b>22</b>. The digital pressure display <b>27</b> displays calibrated pressure from pressure transducer <b>20</b>. The calibration sensor <b>62</b> is mounted within the nozzle attached to hose <b>12</b> and is used only during limited calibration to determine the pressure drop across hose <b>12</b>. The calibration sensor <b>62</b> communicates with digital controller <b>22</b>. The connector <b>64</b> taps into the engine control unit (ECU) of the vehicle and provides a stream of data to digital controller <b>22</b>.

0025The digital controller <b>22</b> also communicates with the pilot valve (pin P<b>9</b> of controller <b>22</b>) which is connected to the deadman control. The controller <b>22</b> transmits a signal to the pilot valve that either opens the pilot valve or closes the pilot valve. When the pilot valve is open, air is supplied to the deadman control. Upon actuating the deadman control by an operator, if the pilot valve is open, air is delivered to the valve, thereby opening butterfly valve <b>32</b> to permit flow of fuel through the valve <b>32</b> toward hoses <b>12</b> and <b>13</b>. Alternatively, when the pilot valve is closed, air is not supplied to the deadman control.

0026The calibration sensor <b>62</b> is a pressure transducer that is mounted in the nozzle attached to hose <b>12</b> for initial calibration of system <b>8</b>. The calibration sensor <b>62</b> is used to characterize the pressure loss of system <b>8</b> due to the length of hose <b>12</b> for various fuel flow rates through the hose. The calibration sensor <b>62</b> is removed from system <b>8</b> after the system is characterized.

0027In operation, calibration sensor <b>62</b> may be used to determine the drop in pressure across system <b>8</b> as follows: the nozzle is inserted in a tank of the aircraft. The engine of the truck is operated so that pump <b>24</b> delivers 100 gallons per minute (for example) to the nozzle. Calibration sensor <b>62</b> measures the back pressure from the aircraft fuel tank at the nozzle and pressure transducer <b>20</b> measures the back pressure at the other end of hose <b>41</b>. The difference between the calibration sensor measurement and the pressure transducer measurement provides the ΔP drop (PSI) that is due to system <b>8</b>. Similarly, the engine may be turned on to deliver a higher speed, so that pump <b>24</b> provides 200 gallons per minute (for example) to the nozzle at the aircraft fuel tank. Again, calibration sensor <b>62</b> measures the pressure at one end of hose <b>41</b>, while pressure transducer <b>20</b> measures the pressure at the other end of hose <b>41</b>. The difference between these two readings provides a drop of pressure (ΔP) due to system <b>8</b>, when the system is delivering 200 gallons per minute (for example). Similarly, the speed of the engine may be increased, so that pump <b>24</b> delivers 300 gallons per minute (for example) at the nozzle attached to the aircraft. Again, calibration sensor <b>62</b> and pressure transducer <b>20</b> measures the pressure at each respective end of hose <b>41</b>. The difference between the two pressure measurements provides the pressure drop (ΔP) for system <b>8</b>, when the pump is delivering 300 gallons per minute (for example).

0028<figref idref="DRAWINGS">FIG. 4</figref> shows an exemplary plot of the drop in system pressure (ΔP) for system <b>8</b> versus the back pressure (for example the back pressure measured by calibration sensor <b>62</b>, or the back pressure measured by pressure transducer <b>20</b>). It will be appreciated that a calibration curve, such as that shown in <figref idref="DRAWINGS">FIG. 4</figref>, may be provided for every nozzle that is attached to the aircraft. For example, the HEPC nozzle may provide one curve, while additional HEPC nozzles may provide a different curve. Each curve is stored in digital controller <b>22</b>, so that the digital controller may set and control the speed of the engine and may control the flow rate of the fuel as desired by the operator.

0029The digital controller <b>22</b> communicates with the ECU of the vehicle, via connector <b>64</b> (pins P<b>3</b> and P<b>4</b> of controller <b>22</b>), and is informed of the speed (for example RPM) of the engine. The digital controller sets the speed of the engine, as further described below.

0030The control system <b>60</b> of bulk fuel delivery system <b>8</b> is configured to regulate the back fuel pressure from the nozzle of hose <b>12</b> so that it does not to exceed 40 PSI. Specifically, controller <b>22</b> is programmed to set fuel pressure, fuel flow rate and engine speed (for example RPM) using three proportional integral derivative (PID) loops. The PID loops maintain fuel pressure, fuel flow rate and engine speed at desired values. Each PID loop corrects any deviation between a measured process variable and a desired setpoint by determining the deviation and providing a corrective action to adjust the process. A PID control algorithm may include three separate parameters, namely, a proportional, an integral and a derivative. The proportional parameter determines the reaction to a current error; the integral determines the reaction based on a sum of recent errors, and the derivative determines the reaction to the rate at which the error is changing. The weighted sum of these three actions may be outputted to a control element to correct the deviation between the measured process variable and the desired set point. According to an embodiment of the invention, the control element is the vehicle's engine. The PID loops adjust the speed of the vehicle's engine to maintain fuel pressure, fuel flow rate and engine speed at desired set points. If the controller <b>22</b> fails, the HEPC of hose <b>12</b> is configured to close valve <b>41</b> in the nozzle to prevent passage of fuel through the nozzle when the fuel pressure reaches 45 PSI. As stated previously, the HEPC is an optional component of hose <b>12</b> and may be omitted.

0031Referring to <figref idref="DRAWINGS">FIG. 5</figref>, there is shown an exemplary method of the present invention, generally designated as <b>70</b>. Method <b>70</b> includes three PID loops shown as steps <b>71</b>, <b>72</b> and <b>73</b>. Step <b>71</b> represents a PID loop executed by digital controller <b>22</b> for setting and controlling the speed (RPM) of the engine. Step <b>72</b> represents a PID loop executed by digital controller <b>22</b> for setting and controlling the flow rate of fuel delivered to the aircraft (GPM, for example). Step <b>73</b> depicts the beginning of the third PID loop. As shown, step <b>73</b> receives the back pressure from transducer <b>20</b> and determines the back pressure at the nozzle. The curve, as shown in <figref idref="DRAWINGS">FIG. 4</figref>, may be used to determine the drop of pressure (ΔP) between the nozzle and pressure transducer <b>20</b>, so that the actual pressure at the nozzle may be obtained.

0032So long as the engine RPM delivers maximum desired flow rate (for example 300 GPM) and the back pressure at the nozzle is less than 40 PSI (for example), as determined by decision block <b>75</b>, the system continues, by way of step <b>76</b>, back to PID loops <b>71</b>, <b>72</b> and <b>73</b>. If, on the other hand, decision block <b>75</b> determines that the pressure is approaching 40 PSI, then steps <b>72</b> and <b>74</b> are entered to set and control the flow rate of fuel so that the set points into PID loop <b>71</b> and PID loop <b>72</b> may be adjusted. The adjustment may be provided to lower the speed of the engine, so that the flow rate of fuel to the aircraft fuel tank is reduced and the back pressure at the nozzle does not exceed 40 PSI.

0033According to one exemplary use of the invention, an operator activates a power take off (PTO) switch in the cabin of the refueling vehicle. The PTO switch transmits a digital input to the transmission of the refueling vehicle to turn on PTO <b>28</b>. If all engine speed conditions are satisfied, PTO <b>28</b> is turned on. The operator deposits a fueling ticket in the ticket printer and then exits the cabin of the vehicle. The operator places the meter register in the RUN position which engages a pilot valve to allow air to flow to a deadman handle. The operator then selects the nozzle of hose <b>12</b>. After the nozzle is connected to the aircraft, the operator squeezes the deadman handle. Squeezing the deadman handle sends air to a switch. The switch sends a digital input to controller <b>22</b> to start the pumping function, while controller <b>22</b> limits engine RPM to 1300 (for example) and flow rate to 300 GPM (for example), or any other values. The controller <b>22</b> also transmits a signal to open butterfly valve <b>32</b>.

0034As the nozzle back pressure reaches 40 PSI, (or any other desired pressure value), the controller reduces engine RPM so that the 40 PSI nozzle back pressure is not exceeded. At this stage of the process, the flow rate does not exceed 300 PSI. Releasing the deadman handle returns the engine back to idle and removes the output to butterfly valve <b>32</b> thereby allowing flow control butterfly <b>32</b> to close under spring pressure.

0035According to another exemplary use of the invention, an operator activates a power take off (PTO) switch in the cabin of the refueling vehicle. The operator places the transmission of the vehicle in drive and the pump begins to turn. The operator deposits a fueling ticket in the ticket printer and then exits the cabin of the vehicle. The operator places the meter register in the RUN position which engages the pilot valve to allow air to flow to a deadman handle. The operator selects the nozzle of hose <b>12</b>. After the nozzle is connected to the aircraft, the operator squeezes the deadman handle. Squeezing the deadman handle sends air to a switch. The switch transmits a digital input to controller <b>22</b> to initiate the pumping function limiting engine speed to 1530 RPM (for example) and flow rate to 800 GPM (for example). When the deadman signal reaches controller <b>22</b>, the controller transmits a signal to open butterfly valve <b>32</b>. Once the nozzle back pressure reaches 40 PSI, the PID loop pressure causes controller <b>22</b> to reduce the engine speed so that the 40 PSI nozzle back pressure is not exceeded. At this stage of the process, the flow rate is unable to exceed 800 GPM (for example). Releasing the deadman handle brings the engine back to idle, and removes the output to butterfly valve <b>32</b> thereby allowing butterfly valve <b>32</b> to close under spring pressure. If a second single point nozzle is selected, the nozzle switch selects an alternate pressure curve to compensate for its pressure loss during fueling. If a set of nozzles are selected (2 deck or 2 side nozzles, for example), controller <b>22</b> uses the pressure curve for the combined set of nozzles and compensates for the pressure loss in the system.