Conventional reciprocating aircraft engines include multiple cylinder head assemblies used to drive a crankshaft. During operation, in order to drive the crankshaft each cylinder head assembly requires fuel, such as provided by a fuel pump. For example, as illustrated in
During operation, as a piston (not shown) reciprocates within each cylinder assembly 12, the piston generates a force within the cylinder assembly 12 sufficient to cause relative motion of the cylinder assembly 12. For example, as a piston within a cylinder assembly 12-1 fires, the loads generated by the piston on the crankshaft causes the cylinder assembly 12-1 to generate a load on the crankcase 22 which carries the cylinder assemblies 12. This load causes the crankcase 22 to bend or flex such that the operational cylinder assembly 12-1 moves relative to the then non-operational cylinder assemblies 12-2, 12-3. To prevent damage to the fuel distribution assembly 14 as caused by the relative motion of the cylinder assemblies, the connector tubes 18 of the fuel delivery assembly are formed of a generally flexible material. As a result, during operation of the aircraft engine 10, as each cylinder assembly 12-1, 12-2, 12-3 moves relative to each other, the connector tubes 18 absorb the motion of the cylinder assemblies 12-1, 12-2, 12-3 relative to the hub 16. Accordingly, the flexibility of the connector tubes 18 helps to prevent the development and propagation of fractures within the fuel delivery system during operation.
Conventional fuel delivery systems for aircraft engines can suffer from certain deficiencies. For example, while the fuel distribution assembly 14 provides fuel to each cylinder assembly 12 from the fuel pump during operation, the fuel distribution assembly 14 cannot purge the fuel contained within the connector tubes 18 at the conclusion of operation of the engine 10. Accordingly, once the engine 10 is turned off, a portion of the fuel contained within the connector tubes 18 drains into the cylinder assemblies 12 through corresponding nozzles 20. In this post-operational state, the cylinder assemblies 12 absorb heat from the engine components which, in turn, vaporizes the fuel contained in the cylinder assemblies 12 and connector tubes 18. Vaporization of the fuel within the fuel distribution assembly 14 can disrupt the operation of the fuel pump during a subsequent operation of the engine. Additionally, in aircraft engines, the cylinder assemblies move independently of each other during operation. This requires a certain amount of compliance in the fuel distribution assembly to minimize damage during operation.
Embodiments of the present invention provide a fuel delivery system that allows fuel to be purged from an engine following engine operation and that allows for relative motion of the cylinder assemblies during operation while minimizing the application of excessive loads on the fuel delivery system. The engine includes a fuel rail and fuel delivery devices, such as fuel injectors, that deliver fuel to corresponding cylinder assemblies. The use of the fuel rail and fuel injectors allows unused fuel to be purged from the engine at the end of the engine's operating cycle, thereby minimizing the creation of fuel vapor within the engine. The fuel rail is assembled from modular fluid conduit adaptors and fluid conduits. With such modularity, a custom fuel rail can be assembled for any size engine. The use of the fluid conduit adaptors and fluid conduits allows motion of the cylinder assemblies relative to the fuel rail during operation to minimize the application of potentially damaging forces on the fuel rail.
In one arrangement, a fuel delivery assembly for an aircraft engine includes a set of fluid conduit adaptors and a set of fluid conduits. Each fluid conduit adaptor of the set of fluid conduit adaptors is constructed and arranged to be secured to a corresponding cylinder assembly of the aircraft engine. Each fluid conduit adaptor of the set of fluid conduit adaptors defines a first lumen constructed and arranged to carry fuel between a fuel inlet and a fuel outlet of the fuel delivery assembly and a second lumen in fluid communication with the first lumen, the second lumen constructed and arranged to provide fuel from the first lumen to the corresponding cylinder assembly. Each fluid conduit of the set of fluid conduits has a first end disposed in fluid communication with the first lumen of a first fluid conduit adaptor of the set of fluid conduit adaptors and an opposing second end disposed in fluid communication with the first lumen of a second fluid conduit adaptor of the set of fluid conduit adaptors. Each fluid conduit of the set of fluid conduits is constructed and arranged to carry fuel between the fuel inlet and the fuel outlet of the fuel delivery assembly. At least one of at least one fluid conduit adaptor of the set of fluid conduit adaptors and at least one fluid conduit of the set of fluid conduits is constructed and arranged to absorb at least a portion of a load generated by motion of a cylinder assembly of the aircraft engine relative to the fuel delivery assembly.
In one arrangement, an aircraft engine includes a crankcase assembly having a crankcase housing and a crankshaft disposed within the crankcase housing. The aircraft engine includes a set of cylinder assemblies coupled to the crankcase housing of the crankcase assembly, each cylinder assembly of the set of cylinder assemblies having a cylinder housing, a piston, and a connecting rod. The piston and connecting rod are disposed within the cylinder housing with the piston coupled to the connecting rod and the connecting rod coupled to the crankshaft. The engine includes a fuel delivery assembly having a set of fluid conduit adaptors and a set of fluid conduits. Each fluid conduit adaptor of the set of fluid conduit adaptors is secured to a corresponding cylinder assembly of the aircraft engine. Each fluid conduit adaptor of the set of fluid conduit adaptors defines a first lumen constructed and arranged to carry fuel between a fuel inlet and a fuel outlet of the fuel delivery assembly and a second lumen in fluid communication with the first lumen, the second lumen constructed and arranged to provide fuel from the first lumen to the corresponding cylinder assembly. Each fluid conduit of the set of fluid conduits has a first end disposed in fluid communication with the first lumen of a first fluid conduit adaptor of the set of fluid conduit adaptors and an opposing second end disposed in fluid communication with the first lumen of a second fluid conduit adaptor of the set of fluid conduit adaptors. Each fluid conduit of the set of fluid conduits is constructed and arranged to carry fuel between the fuel inlet and the fuel outlet of the fuel delivery assembly. At least one of (i) at least one fluid conduit adaptor of the set of fluid conduit adaptors and (ii) at least one fluid conduit of the set of fluid conduits is constructed and arranged to absorb at least a portion of a load generated by motion of a cylinder assembly of the aircraft engine relative to the fuel delivery assembly.
The foregoing and other objects, features and advantages will be apparent from the following description of particular embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments of the invention.
Embodiments of the present invention provide a fuel delivery system that allows fuel to be purged from an engine following engine operation and that allows for relative motion of the cylinder assemblies during operation while minimizing the application of excessive loads on the fuel delivery system. The engine includes a fuel rail and fuel delivery devices, such as fuel injectors, that deliver fuel to corresponding cylinder assemblies. The use of the fuel rail and fuel injectors allows unused fuel to be purged from the engine at the end of the engine's operating cycle, thereby minimizing the creation of fuel vapor within the engine. The fuel rail is assembled from modular fluid conduit adaptors and fluid conduits. With such modularity, a custom fuel rail can be assembled for any size engine. The use of the fluid conduit adaptors and fluid conduits allows motion of the cylinder assemblies relative to the fuel rail during operation to minimize the application of potentially damaging forces on the fuel rail.
Each cylinder assembly 60, as indicated in a cut-away view of a cylinder assembly in
The fuel delivery system 56 is configured to provide fuel from a fuel source 92 to each of the cylinder assemblies 60. As indicated in
The fuel rail 79 is disposed between a fuel inlet 88 and a fuel outlet 90. In one arrangement, as particularly illustrated in
In one arrangement, with particular reference to
As illustrated in
Each fluid conduit 82-1, 82-1 is formed as a generally tubular structure from a substantially rigid material, such as steel. While any number of fluid conduits 82 can be used as part of the fuel rail, in the arrangement illustrated, the fuel rail 79 includes a first fluid conduit 82-1 and a second fluid conduit 82-2. The fluid conduits 82 couple to the fluid conduit adaptors 80 to provide fluid communication between the fluid inlet 88 and the fluid outlet 90. For example, the first fluid conduit 82-1 is coupled to and provides fluid communication between a first fluid conduit adaptor 80-1 and a second fluid conduit adaptor 80-2 while the second fluid conduit 82-2 is coupled to and provides fluid communication between the second fluid conduit adaptor 80-2 and a third fluid conduit adaptor 80-3.
In one arrangement, the number of fluid conduit adaptors 80 within the fuel rail 79 corresponds to the number of cylinder assemblies 60 disposed on either the first or second side of the crankcase housing 58. For example, with reference to
Each fluid conduit adaptor 80 is configured to be coupled to the fluid conduits 82 to form the fuel rail 79. For example, with reference to
Each fluid conduit adaptor 80 is configured to divert a portion of the fuel flowing through the fuel rail 79 into a corresponding cylinder assembly 60. For example, each fluid conduit adaptors 80 also defines and a second lumen 106 in fluid communication with the first lumen 104 where the second lumen 106 diverts a portion of the fuel flowing through the first lumen 104 to a corresponding cylinder assembly 60.
While each fluid conduit adaptor 80 can be constructed and arranged to provide fuel to a corresponding cylinder assembly 60, in one arrangement, the fluid conduit adaptor 80 includes a fuel delivery device 59 that delivers fuel to the cylinder assembly 60. In one arrangement, at least a portion of a fuel delivery device 59, such as a fuel injector, is disposed within the second lumen 106. With reference to
In one arrangement, as indicated in
The fluid conduit adaptors 80 are also constructed and arranged to allow for relative motion of the cylinder assemblies 60 during operation while minimizing the application of excessive loads on portions of the fuel rail 79. In one arrangement, each fluid conduit adaptor 80 includes a compliant member 120 disposed between the fluid conduit adaptor 80 and a corresponding fluid conduit 82. For example, with reference to
In use, and with particular attention to
With particular reference to cylinder assembly 60-2, as the cylinder assembly 60-1 moves along a substantially vertical direction 127, along a substantially horizontal direction 128, or along some combination of the two directions 127, 128, the cylinder assembly 60-2 moves the fluid conduit adaptor 80-2 relative to the fluid conduits 82-1, 82-2. Accordingly, because the compliant members 120-1, 120-2 are disposed between the fluid conduit adaptor 80-2 and the fluid conduits 82-1, 82-2, the compliant members 120-1, 120-2 become compressed in response to such motion. This compression helps to absorb a least a portion of the load generated by the cylinder assembly 60-2 on the fuel rail 79 (e.g., the load generated on the fuel conduits 82-1, 82-2), thereby minimizing excessive loading on and potential damage to the fuel rail 79.
At the conclusion of the engine's operation, because the engine 50 is configured with the fuel rail 79 as described above, a user can drain fuel from the engine to minimize vaporization of the fuel within the engine 50. For example, with respect to
While various embodiments of the invention have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
For example, as indicated above, the fluid conduit adaptors 80 are constructed and arranged to secure the fuel rail 79 to corresponding cylinder assemblies 60 of the aircraft engine 50. In one arrangement, each of the fluid conduit adaptors 80 are moveably coupled a corresponding cylinder assembly 60. In one arrangement, with particular reference to
For example, assume that during operation, the second cylinder assembly 60-2 fires and generates a horizontal and vertical load on the fuel rail 79. The compliant members 112-1 and 112-2 of the fluid conduit adaptor 80-2 absorb at least some of the vertical and longitudinal forces generated by the cylinder assembly 60-2 on the fuel rail 79. However, generally longitudinal motion of the cylinder assembly 60-2 can cause the fuel rail 79 to translate along the longitudinal direction 128 relative to adjacent cylinder assemblies 60-1, 60-3. Because the diameter of the apertures 112 for each fluid conduit adaptor 80-1, 80-3 is larger than an outer diameter of the protrusion for each adjacent cylinder assembly 60-1, 60-3, substantially longitudinal translation of the fuel rail 79 causes the fluid conduit adaptor 80-1, 80-3 to translate relative to the protrusions of each cylinder assembly 60-1, 60-3. Accordingly, the configuration of the fluid conduit adaptors 80 minimizes loading of the fuel rail 79 at any of the locations of the fluid conduit adaptors 80 as caused by longitudinal translation of the fuel rail 79 within the engine 50.
As indicated above, the fluid conduit adaptors 80 include compliant members 120, disposed in proximity to corresponding fluid conduits 82, that are configured to absorb at least a portion of the lateral and vertical loads applied to the fuel rail 79 by a corresponding cylinder assembly 60. In one arrangement, the fuel delivery devices 59 also operate to absorb these lateral and vertical loads. For example, with particular attention to
As described above, the fuel conduits 82 are formed of a substantially rigid material while the fluid conduit adaptors 80 include compliant members 120 disposed between the fluid conduit adaptor 80 and the fuel conduits 82. The compliant members 120 are configured to absorb at least a portion of a load generated by the cylinder assemblies 60 on the fuel rail 80 during operation. Such description is by way of example only. In one arrangement, as illustrated in
Each fluid conduit adaptor 180 includes a first adaptor portion 185 and a second adaptor portion 187. The first adaptor portion 185 secures the fluid conduit adaptor 180 to a corresponding cylinder assembly, such as cylinder assembly 160-1 shown in
The fuel conduits 182 are constructed and arranged to allow for relative motion of the cylinder assemblies 160 during operation while minimizing the application of excessive loads on portions of the fuel rail 179. In one arrangement, each fluid conduit 182 is formed from a compliant material such as a rubber material. The compliant fluid conduits 182 are configured to absorb at least a portion of a load generated by the cylinder assemblies 60 on the fuel rail 80 during operation. For example, in use operation of the cylinder assemblies 160 causes an associated crankcase housing (not shown) to flex or bend, such as at the location of cylinder assemblies 60. Accordingly, such flexure causes each cylinder assembly 60 and attached fluid conduit adaptor 180 to move relative to the fuel conduits 182 of the fuel rail 79.
With particular reference to cylinder assembly 160-2, as the cylinder assembly 160-1 moves along a substantially vertical direction 227, along a substantially horizontal direction 228, or along some combination of the two directions 227, 228, the cylinder assembly 160-2 moves the fluid conduit adaptor 180-2 relative to the fluid conduits 182-1, 182-2. Accordingly, because the fluid conduits 182-1, 182-2 are formed of a compliant material, the fluid conduits 182-1, 182-2 become expanded or contracted in response to such motion. This expansion or contraction helps to absorb a least a portion of the load generated by the cylinder assembly 160-2 on the fuel rail 179 (e.g., the load generated on the fuel conduits 182-1, 182-2), thereby minimizing excessive loading on and potential damage to the fuel rail 179.
This patent application claims the benefit of U.S. Provisional Patent Application No. 60/926,038 filed on Apr. 24, 2007, entitled, “FULLY CONSTRAINED FUEL INJECTOR MOUNT FOR COMPLIANT FUEL DELIVERY SYSTEM”, the contents and teachings of which are hereby incorporated by reference in their entirety.
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Number | Date | Country | |
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60926038 | Apr 2007 | US |