Fuel pump for engine

• US 20080199302A1
• Filed: 02/20/2007
• Published: 08/21/2008
• Est. Priority Date: 02/20/2007
• Status: Active Grant

• Current Assignee: Lycoming Engines
• Original Assignee: Lycoming Engines
• Inventors: Lysinger, Forrest Ross, Morris, James Paul, Matas, Scott, Gundrum, William
• Granted Patent: US 7,828,509 B2
• Time in Patent Office: Days
• US Class Current: 415/55.1
• CPC Class Codes: F02M 37/045 Arrangements for driving rotary positive-displacement pumps
• CPC Class Codes: F04C 14/26 using bypass channels
• CPC Class Codes: F04C 15/0038 Shaft sealings specially adapted for rotary-piston machines or pumps

Abstract

A fuel pump includes a bearing element disposed in proximity to an impeller. The bearing element is configured to form a fuel seal with the impeller and to drain fuel leaked from the pump chamber back into the pump chamber. The bearing element minimizes leakage of fuel from the pump chamber into an engine coupled to the impeller. The fuel pump also includes redundant lip seals configured to provide redundant sealing relative to a shaft of the impeller within the fuel pump in order to minimize engine oil from entering the pump chamber and to minimize fuel from entering the engine. Integration of both the bearing element and the redundant lip seals as part of the fuel pump results in the fuel pump having a relatively compact size.

Claims

1. A fuel pump, comprising:

a housing;

an impeller disposed within the housing, the impeller and the housing (i) defining a pump chamber having a pump inlet and a pump outlet and (ii) defining a housing chamber, the impeller being operable to rotate within the housing to transfer fuel from the pump inlet, through the pump chamber to the pump outlet;

a bearing element disposed within the housing chamber about a shaft of the impeller, the bearing element having a sealing face opposing the impeller and being operable to form a fuel seal with the impeller; and

a first lip seal disposed within the housing chamber about the shaft of the impeller and a second lip seal disposed within the housing chamber about the shaft of the impeller, the first lip seal being disposed between the bearing element and the second lip seal, the first lip seal being operable to form a fuel seal with the shaft of the impeller and the second lip seal being operable to form an oil seal with the shaft of the impeller.

2. The fuel pump of claim 1, wherein the bearing element defines a channel within the sealing interface extending from an inner periphery of the bearing element to an outer periphery of the bearing element, the channel being operable to collect fuel leaked from the pump chamber and to direct the leaked fuel toward the pump inlet of the fuel pump.

3. The fuel pump of claim 1, further comprising a carrier sleeve disposed within the housing chamber of the housing, the first lip seal and the second lip seal being coupled to the carrier sleeve such that the first lip seal and the second lip seal define a fluid containment volume between the first lip seal and the second lip seal, the carrier sleeve defining a drain port in fluid communication with the fluid containment volume and in fluid communication with an outflow port of the housing.

4. The fuel pump of claim 3, wherein the carrier sleeve defines a channel disposed about an outer periphery of the carrier sleeve and wherein the carrier sleeve defines a plurality of drain ports disposed about a circumference of the carrier sleeve, the plurality of drain ports in fluid communication with the fluid containment volume defined between the first lip seal and the second lip seal and in fluid communication with the channel, at least one of the plurality of drain ports in fluid communication with the outflow port of the housing.

5. The fuel pump of claim 1, wherein at least one of the first lip seal and the second lip seal comprises a first sealing portion and a second sealing portion disposed about the shaft of the impeller, the first sealing portion and the second sealing portion disposed in a spaced apart relationship relative to each other.

6. The fuel pump of claim 1, wherein the housing defines a high pressure bypass chamber in fluid communication with the pump chamber and wherein the fuel pump comprises a high pressure bypass ball valve disposed within the high pressure bypass chamber.

7. The fuel pump of claim 1, wherein the housing defines a low pressure bypass chamber in fluid communication with the pump chamber and wherein the fuel pump comprises a low pressure bypass ball valve disposed within the low pressure bypass chamber.

8. The fuel pump of claim 1, comprising a fuel filter disposed within a pump outlet chamber defined by the pump outlet, the fuel filter in fluid communication with the pump chamber of the housing and being operable to receive a flow of fuel from the pump chamber.

9. The fuel pump of claim 1, wherein the shaft of the impeller comprises a drive element being operable to couple the impeller to an impeller driving apparatus of an engine, the drive element having a reduced diameter portion, the reduced diameter portion having a diameter that is smaller than a diameter of the shaft of the impeller.

10. An engine assembly, comprising:

an engine; and

a fuel pump coupled to the engine, the fuel pump comprising;

a housing,

an impeller disposed within the housing, the impeller and the housing defining a pump chamber having a pump inlet and a pump outlet and defining a housing chamber, the impeller being operable to rotate within the housing to transfer fuel from the pump inlet, through the pump chamber, and to the engine via the pump outlet,

a bearing element disposed within the housing chamber about a shaft of the impeller, the bearing element having a sealing face opposing the impeller and being operable to form a fuel seal with the impeller, and

a first lip seal disposed within the housing chamber about the shaft of the impeller and a second lip seal disposed within the housing chamber about the shaft of the impeller, the first lip seal disposed between the bearing element and the second lip seal, the first lip seal being operable to form a fuel seal with the shaft of the impeller and the second lip seal being operable to form an oil seal with the shaft of the impeller.

11. The engine assembly of claim 10, wherein the bearing element defines a channel within the sealing interface extending from an inner periphery of the bearing element to an outer periphery of the bearing element, the channel being operable to collect fuel leaked from the pump chamber and to direct the leaked fuel toward the pump inlet of the fuel pump.

12. The engine assembly of claim 10, further comprising a carrier sleeve disposed within the housing chamber of the housing, the first lip seal and the second lip seal being coupled to the carrier sleeve such that the first lip seal and the second lip seal define a fluid containment volume between the first lip seal and the second lip seal, the carrier sleeve defining a drain port in fluid communication with the fluid containment volume and in fluid communication with an outflow port of the housing.

13. The engine assembly of claim 12, wherein the carrier sleeve defines a channel disposed about an outer periphery of the carrier sleeve and wherein the carrier sleeve defines a plurality of drain ports disposed about a circumference of the carrier sleeve, the plurality of drain ports in fluid communication with the fluid containment volume defined between the first lip seal and the second lip seal and in fluid communication with the channel, at least one of the plurality of drain ports in fluid communication with the outflow port of the housing.

14. The engine assembly of claim 10, wherein at least one of the first lip seal and the second lip seal comprises a first sealing portion and a second sealing portion disposed about the shaft of the impeller, the first sealing portion and the second sealing portion disposed in a spaced apart relationship relative to each other.

15. The engine assembly of claim 10, wherein the housing defines a high pressure bypass chamber in fluid communication with the pump chamber and wherein the fuel pump comprises a high pressure bypass ball valve disposed within the high pressure bypass chamber.

16. The engine assembly of claim 10, wherein the housing defines a low pressure bypass chamber in fluid communication with the pump chamber and wherein the fuel pump comprises a low pressure bypass ball valve disposed within the low pressure bypass chamber.

17. The engine assembly of claim 10, comprising a fuel filter disposed within a pump outlet chamber defined by the pump outlet, the fuel filter in fluid communication with the pump chamber of the housing and being operable to receive a flow of fuel from the pump chamber.

18. The engine assembly of claim 10, wherein the impeller shaft comprises a drive element being operable to couple the impeller to an impeller driving apparatus of an engine, the drive element having a reduced diameter portion, the reduced diameter portion having a diameter that is smaller than a diameter of the impeller shaft.

19. A method for assembly of a fuel pump, comprising:

disposing an impeller within a housing, the impeller and the housing defining a pump chamber having a pump inlet and a pump outlet and defining a housing chamber, the impeller being operable to rotate within the housing to transfer fuel from the pump inlet, through the pump chamber to the pump outlet;

disposing a bearing element within the housing chamber about a shaft of the impeller, the bearing element having a sealing face opposing the impeller and being operable to form a fuel seal with the impeller; and

disposing a first lip seal within the housing chamber about the shaft of the impeller and a second lip seal disposed within the housing chamber about the shaft of the impeller, the first lip seal disposed between the bearing element and the second lip seal, the first lip seal being operable to form a fuel seal with the shaft of the impeller and the second lip seal being operable to form an oil seal with the shaft of the impeller.

20. The method of claim 19, comprising disposing a carrier sleeve within the housing chamber of the housing, the first lip seal and the second lip seal being coupled to the carrier sleeve such that the first lip seal and the second lip seal define a fluid containment volume between the first lip seal and the second lip seal, the carrier sleeve defining a drain port in fluid communication with the fluid containment volume and in fluid communication with an outflow port of the housing.

21. The method of claim 19, comprising disposing a high pressure bypass ball valve within a high pressure bypass chamber defined by the housing, the high pressure bypass ball valve in fluid communication with the pump chamber.

22. The method of claim 19, comprising disposing a low pressure bypass ball valve within a low pressure bypass chamber defined by the housing, the low pressure bypass ball valve in fluid communication with the pump chamber.