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.
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 delivery system having 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 delivery system also includes fuel rail coupling members that are constructed and arranged to secure each cylinder assembly to the fuel rail and to absorb at least a portion of a load generated by the corresponding cylinder assembly on the fuel rail during operation. The fuel rail coupling members allow motion of the cylinder assemblies relative to the fuel rail during operation and minimize the application of potentially damaging forces on the fuel rail.
In one arrangement, a fuel delivery system for an aircraft engine includes a fuel rail, a set of fuel delivery devices, and a set of fuel rail coupling members. The fuel rail includes a set of fuel delivery ports disposed between a fuel inlet and a fuel outlet of the fuel rail. Each fuel delivery device of the set of fuel delivery devices is disposed between each fuel delivery port of the set of fuel delivery ports and a corresponding cylinder assembly of the aircraft engine. Each fuel delivery device is configured to provide fuel from the fuel rail to the corresponding cylinder assembly. Each fuel rail coupling member of the set of fuel rail coupling members is constructed and arranged to secure a corresponding cylinder assembly to the fuel rail and to absorb a load generated by the corresponding cylinder assembly on the fuel rail.
In one arrangement, a fuel delivery system for an aircraft engine includes a crankcase assembly, a set of cylinder assemblies, and a fuel delivery system. The crankcase assembly includes a crankcase housing and a crankshaft disposed within the crankcase housing. Each cylinder assembly of the a set of cylinder assemblies having a cylinder housing, a piston, and a connecting rod, the piston and connecting rod being disposed within the cylinder housing, the piston coupled to the connecting rod and the connecting rod coupled to the crankshaft. The fuel delivery system includes a fuel rail, a set of fuel delivery devices, and a set of fuel rail coupling members. The fuel rail includes a set of fuel delivery ports disposed between a fuel inlet and a fuel outlet of the fuel rail. Each fuel delivery device of the set of fuel delivery devices is disposed between each fuel delivery port of the set of fuel delivery ports and a corresponding cylinder assembly of the set of cylinder assemblies. Each fuel delivery device is configured to provide fuel from the fuel rail to the corresponding cylinder assembly. Each fuel rail coupling member of the set of fuel rail coupling members is constructed and arranged to secure a corresponding cylinder assembly to the fuel rail and to absorb a load generated by the corresponding cylinder assembly on the fuel rail as the piston and connecting rod reciprocate within the cylinder housing.
In one arrangement, a method for assembling a fuel delivery system of an aircraft engine includes disposing a fuel rail within the aircraft engine, the fuel rail having a set of fuel delivery ports disposed between a fuel inlet and a fuel outlet of the fuel rail. The method includes securing the fuel rail to a set of cylinder assemblies using a set of fuel rail coupling members, each fuel rail coupling member of the set of fuel rail coupling members securing a corresponding cylinder assembly to the fuel rail, each fuel rail coupling member constructed and arranged to absorb a load generated by the corresponding cylinder assembly on the fuel rail. The method includes disposing a set of fuel delivery devices between each fuel delivery port of the set of fuel delivery ports and the corresponding cylinder assembly of the aircraft engine, each fuel delivery device configured to provide fuel from the fuel rail to the corresponding cylinder 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 for an engine that allows fuel to be purged from the engine following engine operation and that minimizes the ability for the engine to place excessive loads on the fuel delivery system. The engine includes a fuel delivery system having 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 delivery system also includes fuel rail coupling members that are constructed and arranged to secure each cylinder assembly to the fuel rail and to absorb load generated by the corresponding cylinder assembly on the fuel rail during operation. The fuel rail coupling members allow motion of the cylinder assemblies relative to the fuel rail during operation and 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 to each of the cylinder assemblies 60. In one arrangement, the fuel delivery system 56 includes a fuel rail 80, a set of fuel delivery devices 59, and a set of fuel rail coupling members 84. The fuel rail 80 is configured as a generally tubular structure having a set of fuel delivery ports 86 disposed between a fuel inlet 88 and a fuel outlet 90. In one arrangement, as particularly illustrated in
As indicated in
In one arrangement, with particular reference to
The fuel rail 80 provides fuel to the cylinder assemblies via fuel delivery devices 59. Each fuel delivery device of the set of fuel delivery devices 59 is configured to divert a portion of the fuel flowing through the fuel rail 80 into a corresponding cylinder assembly 60. For example, as indicated in
The set of fuel rail coupling members 84 are configured to secure the fuel rail 80 to the set of cylinder assemblies 54. The set of fuel rail coupling members 84 are also constructed and arranged to absorb loads generated by the corresponding cylinder assembly 60 relative to the fuel rail 80 during operation. For example, to fuel rail coupling members 84 allow the cylinder assemblies 60 in the set of cylinder assemblies 54 to move relative to each other while minimizing the load that each cylinder assembly 60 places on the fuel rail 80 during operation. Accordingly, the fuel rail coupling members 84 secure the fuel rail 80 to the engine 50 while minimizing potential damage to the fuel rail 80 as caused by operation of the engine 50.
As illustrated in the embodiment shown
While the fuel rail coupling members 84 can be configured in a variety of ways, in one arrangement and with particular reference to the fuel rail coupling member 84-1 of
In use, and with particular attention to
With particular reference to cylinder assembly 60-1, as the cylinder assembly 60-1 moves along a substantially vertical direction 104, along a substantially horizontal direction 106, or along some combination of the two directions 104, 106, the cylinder assembly 60-1 moves the bracket 102 relative to the fuel rail 80. Accordingly, because the compliant support 100 is disposed between the fuel rail 80 and the bracket 102, the compliant support 100 becomes compressed in response to such loading. This compression helps to absorb a least a portion of the load generated by the cylinder assembly 60-1 on the fuel rail 80, thereby minimizing excessive loading on and potential damage to the fuel rail 80.
At the conclusion of the engine's operation, because the engine 50 is configured with the fuel delivery system 56 as described above, a user can drain fuel from the engine to minimize vaporization of the fuel within the engine 50. For example, while the engine 80 is hot after operation, the fuel pressure regulator 96 receives unused fuel from the cylinder assemblies 60 and from the fuel rail 80 via fuel outlet 90 and delivers the unused fuel to the fuel source 92. Accordingly, because the fuel delivery system 56 allows fuel to be purged from the engine 50 after engine operation, the fuel delivery system 56 minimizes the ability for portions of the engine 50 to become disrupted by fuel vaporization.
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, each bracket 102 of the fuel rail coupling members 84 is configured to secure a corresponding compliant support 100 to the fuel rail 80 and to secure the fuel rail 80 to a corresponding cylinder assembly. In one arrangement, each bracket 102 is 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 80. The compliant support 102 of the coupling member 84-2 absorbs at least some of the vertical and longitudinal forces generated by the cylinder assembly 60-2 on the fuel rail 80. However, generally longitudinal motion of the cylinder assembly 60-2 can cause the fuel rail 80 to translate along the longitudinal direction 106 relative to adjacent cylinder assemblies 60-1, 60-3. Because the diameter of the aperture 112 for each coupling member 84-1, 84-3 is larger than an outer diameter of the protrusion 114 for each adjacent cylinder assembly 60-1, 60-3, substantially longitudinal translation of the fuel rail 80 causes the brackets 102 to translate relative to the protrusions 114 of each cylinder assembly 60-1, 60-3. Accordingly, the configuration of the brackets minimizes loading of the fuel rail 80 at any of the locations of the coupling member 84-1, 84-3 as caused by longitudinal translation of the fuel rail 80 within the engine 50.
As indicated above, the fuel rail coupling members 84 include compliant supports configured to absorb at least a portion of the lateral and vertical loads applied to the fuel rail 80 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 indicated above, the fuel rail 80 is configured as a generally tubular structure having a set of fuel delivery ports 86 disposed between a fuel inlet 88 and a fuel outlet 90. In one arrangement, the fuel rail 80 also includes one or more fuel sensor ports 130 each of which configured to carry a corresponding fuel sensor 132, such as a temperature sensor or a pressure sensor. The fuel sensors 132 allow various aspects (i.e., pressure, temperature) of the fuel to be electronically monitored such as by a central controller (not shown). As a result of such monitoring, the controller can adjust various parameters of the engine 50 to minimize fuel consumption and/or maximize operating efficiency of the engine 50.
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