Devices, systems, and methods for variable flow rate fuel ejection

Patent metadata

Field	Value
Publication number	US-9719529-B2
Application number	US-201213983676-A
Country	US
Kind code	B2
Filing date	Feb 3, 2012
Priority date	Feb 3, 2011
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

Devices, systems, and methods for variable flow rate fuel ejection are disclosed. A variable flow rate ejector comprises primary and secondary inlets, primary and secondary nozzles, and a needle. The primary nozzle is connected to receive a first fluid from the first inlet chamber and transmit the first fluid through a primary nozzle opening. The needle is disposed within the primary nozzle opening and is axially movable to vary an area of primary nozzle opening. The primary nozzle opening and the needle are sized to make the flow of the first fluid have a supersonic speed. The secondary inlet opens into a second inlet chamber positioned outside the primary nozzle opening. A portion of the second fluid is entrained in the flow of the first fluid from the primary nozzle. The secondary nozzle opening is sized to make the flow of the first and second fluids have a subsonic speed.

First claim

What is claimed:

1. A variable flow rate ejector comprising:
a primary inlet configured to be connected to a first fluid source at a first pressure, the primary inlet opening into a first inlet chamber;
a primary nozzle defining an opening at an end thereof, the primary nozzle connected to receive the first fluid from the first inlet chamber and transmit a flow of the first fluid through the primary nozzle opening;
a needle disposed within the primary nozzle opening and having a tapered portion, the tapered portion of the needle having a length greater than a largest diameter of the needle, the needle axially movable in order to vary an area between the tapered portion of the needle and primary nozzle opening, the primary nozzle opening and the needle sized to cause the first fluid to flow through the primary nozzle at supersonic speed when the first fluid source is connected to the primary inlet at the first pressure;
a secondary inlet configured to be connected to a second fluid source at a second pressure lower than the first pressure, the secondary inlet opening into a second inlet chamber positioned outside the primary nozzle opening, the second inlet chamber disposed so that when the second fluid source is connected to the secondary inlet at the second pressure, at least a portion of the second fluid is entrained in the flow of the first fluid from the primary nozzle, thereby creating a flow of the first and second fluids as a combined fluid; and
a secondary nozzle defining another opening downstream of the primary nozzle opening, the secondary nozzle opening sized to cause subsonic flow of the combined fluid through the secondary nozzle opening,
wherein an axial distance from an outermost edge of the primary nozzle opening to a narrowest portion of the secondary nozzle opening is less than a diameter of the narrowest portion of the secondary nozzle opening.

2. The variable flow rate ejector of claim 1 , wherein the secondary nozzle opening has a diameter from one to five times a diameter of the primary nozzle opening.

3. The variable flow rate ejector of claim 2 , wherein the subsonic speed of the combined fluid through the secondary nozzle is approximately 90% of Mach 1.

4. The variable flow rate ejector of claim 1 , further comprising a diffuser positioned downstream of the secondary nozzle opening, the diffuser configured to discharge the flow of the first and second fluids at a pressure greater than the second pressure.

5. The variable flow rate ejector of claim 4 , wherein the diffuser comprises a tapered portion that widens in the direction of the flow of the first and second fluids.

6. The variable flow rate ejector of claim 4 , wherein the secondary nozzle comprises a constant-width throat portion extending between the secondary nozzle opening and the diffuser.

7. The variable flow rate ejector of claim 6 , wherein the throat portion has a length of at least approximately six times a diameter of the throat portion.

8. The variable flow rate ejector of claim 1 , further comprising means for axially moving the needle.

9. The variable flow rate ejector of claim 8 , wherein the means for axially moving the needle comprises an electric stepper motor.

10. The variable flow rate ejector of claim 1 , further comprising the first fluid source connected to the primary inlet at the first pressure and the second fluid source connected to the secondary inlet at the second pressure.

11. The variable flow rate ejector of claim 10 , further comprising:
means for axially moving the needle;
a pressure sensor disposed downstream of the ejector secondary nozzle;
an ejector control unit in communication with the pressure sensor and the means for axially moving the needle, the ejector control unit configured to axially move the ejector needle to maintain fluid flow from the ejector at a predetermined pressure based on pressure sensed by the pressure sensor.

12. A closed-loop fuel cell system comprising:
a fuel cell having an anode circuit, a gas inlet, and a gas outlet; and
the variable flow rate ejector of claim 1 , the primary inlet of the ejector connected to a hydrogen storage system to receive a high pressure hydrogen gas, the secondary inlet of the ejector connected to the gas outlet of the fuel cell to receive a low pressure hydrogen gas, the secondary nozzle of the ejector connected to discharge a flow of the hydrogen gases to the gas inlet of the fuel cell.

13. The closed loop fuel cell system of claim 12 , further comprising:
a pressure sensor disposed between the ejector and the gas inlet of the fuel cell, the pressure sensor operable to sense a pressure of the flow of the hydrogen gases to the gas inlet of the fuel cell.

14. The closed-loop fuel cell system of claim 13 , further comprising:
an ejector control unit in communication with the pressure sensor and the ejector, the ejector control unit configured to axially move the ejector needle to maintain the flow of the hydrogen gases from the ejector to the gas inlet of the fuel cell at a predetermined pressure based on the sensed pressure.

15. The closed loop fuel cell system of claim 12 , further comprising:
a separator disposed between the gas outlet of the fuel cell and the second inlet of the ejector, the separator configured to separate water from the low pressure hydrogen gas; and
a purge valve connected to the separator, the purge valve configured to remove the separated water from the system.

16. A method for recirculating hydrogen gas inside a fuel cell system, the method comprising the steps of:
operating the fuel cell system of claim 12 ;
generating with the anode circuit a greater quantity of hydrogen gas than is required by a reaction rate of the fuel cell;
discharging from the gas outlet of the fuel cell an excess quantity of hydrogen gas;
supplying the high pressure hydrogen gas to the primary inlet of the ejector;
supplying the excess quantity of hydrogen gas to the secondary inlet of ejector; and
controlling the flow of the hydrogen gases from the ejector to the gas inlet of the fuel cell to match the reaction rate of the fuel cell.

17. The method of claim 16 , further comprising the step of:
sensing a pressure of the flow of the hydrogen gases from the ejector to the gas inlet of the fuel cell.

18. The method of claim 17 , wherein the controlling step comprises:
controlling the flow of the hydrogen gases from the ejector to the gas inlet of the fuel cell by axially moving the ejector needle based on the sensed pressure of the flow of the hydrogen gases.

19. The method of claim 16 , wherein the discharging step comprises:
discharging from the gas outlet of the fuel cell a mixture of the excess quantity of hydrogen gas and water;
and further comprising the steps of:
separating the water from the excess hydrogen gas; and
removing the separated water from the system.

Assignees

• Brunner Douglas
• Bajpai Manish W
• Kinzey John Adam C
• Marcks Shane
• Prasad Ajay K
• Advani Suresh G
• Univ Delaware

Inventors

• Brunner Douglas
• Bajpai Manish W
• Kinzey John Adam C
• Marcks Shane
• Prasad Ajay K
• Advani Suresh G

Classifications

• F02M21/0206

  Non-hydrocarbon fuels, e.g. hydrogen, ammonia or carbon monoxide · CPC title

• F04F5/466 Primary

  with a plurality of nozzles arranged in parallel · CPC title

• H01M8/04164

  by condensers, gas-liquid separators or filters · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title

• F04F5/52 Primary

  of evacuating pumps · CPC title