Conventional piston aircraft engines include multiple cylinder assemblies used to drive a crankshaft. In order to drive the crankshaft, each cylinder assembly requires fuel, such as provided by a fuel pump. For example, as illustrated in
During operation, a spark plug of each cylinder assembly 12 ignites the fuel received from the fuel distribution assembly 14 and causes reciprocation of a piston (not shown) contained within each cylinder assembly 12. As each piston reciprocates, each piston generates a force within the corresponding cylinder assembly 12 sufficient to cause relative motion of the cylinder assemblies 12. For example, as a piston within cylinder assembly 12-1 fires, the loads generated by the piston on the crankshaft causes the cylinder assembly 12-1 to generate a corresponding load on the crankcase 22. 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.
Historically, conventional aircraft engines have used mechanical systems to provide direct or indirect fuel distribution to the cylinder assemblies. For example, in the aircraft engine 10 illustrated in
In comparison to the fuel distribution assembly 14 used in certain aircraft engines, conventional automotive engines utilize electrically actuated fuel injectors to deliver fuel to corresponding cylinder assemblies. For example, a conventional automotive engine includes multiple cylinder assemblies where each cylinder assembly includes a fuel injector having an inboard end coupled to the cylinder assembly and an outboard end coupled to a rigid fuel-delivery rail. Conventional automotive fuel-delivery rails are attached to the engine's cylinder assemblies to support the outboard ends of the fuel injector valves and to supply fuel to each of the fuel injection valves.
The availability of electrically actuated fuel injectors produced for the automotive market has initiated the application of these automotive fuel injectors for piston aircraft engines. The use of electrically actuated fuel injectors as part of an aircraft engine can help to minimize vapor lock to allow unused fuel to be purged from the aircraft engine at the end of the engine's operating cycle. However, conventional automotive fuel-delivery rail designs for electrically actuated fuel injectors are not directly applicable for use with aircraft engines. For example, use of the automotive rigid fuel-delivery rail design in an aircraft engine can interfere with the location of the aircraft engine's cooling baffles and cowlings. Also, as indicated above, the individual cylinder assemblies of the aircraft engine move relative to each other during operation due to the loads generated by the pistons on the crankshaft and differential thermal expansion of the cylinder assemblies. With a rigid fuel rail design in an aircraft engine, these movements can cause fretting wear between the fuel injectors and the fuel rails, thereby reducing fatigue life and decreasing the probability of leak free operation. Additionally, the use of a rigid fuel rail design with fuel injectors in an aircraft engine can create a tolerance stackup for the individual cylinder assemblies relative to the fuel rail, thereby creating alignment issues with respect to the fuel injectors. For example, current rigid fuel-delivery rail designs introduce angular misalignment between each inboard injector port, as carried by each cylinder assembly, and the fuel rail. The angular misalignment produces side loading on both ends of the fuel injector body and causes poor dispersion and atomization of the fuel provided to each cylinder assembly. This irregular and non-atomized fuel delivery, in turn, causes irregular operation of the aircraft engine over a variety of engine speed ranges, reduces the overall fuel efficiency of the engine, and potentially reduces the detonation or knock margin of the engine.
In order to utilize fuel injectors with piston aircraft engines and to solve the deficiencies caused by the conventional rigid fuel-delivery rail designs, manufacturers can utilize flexible connectors, such as compliant tubing, as part of a fuel line to interconnect each of the fuel injectors and to provide fuel from the engine's fuel pump to each of the cylinder assemblies. However, the use of flexible tubing alone does not maintain an adequate seal between each fuel injector and a corresponding cylinder assembly and between each fuel injector and the flexible fuel line. Accordingly, the inadequate seals can lead to fuel leakage.
Embodiments of the present invention relate to a fuel injector mounting assembly for an aircraft engine fuel delivery system. The fuel injector mounting assembly is configured to limit or constrain movement of a fuel injector relative to a corresponding cylinder assembly. For example, the fuel injector mounting assembly includes a base that is secured to a cylinder assembly's housing and a fuel conduit. The fuel conduit includes a first fuel conduit portion which operates in conjunction with a cylinder assembly's fuel manifold to capture a fuel injector between the fuel injector mounting assembly and the cylinder assembly's fuel manifold. The fuel conduit also includes a second fuel conduit portion which is secured to a compliant fuel line. With such a configuration of the fuel injector mounting assembly, both ends of the fuel injector are secured to the cylinder assembly to minimize any relative motion in the fuel injector's seals relative to either the cylinder assembly's fuel manifold or to the compliant fuel line. In one arrangement, the fuel injector mounting assembly controls the angular position of the fuel injector relative to a fuel manifold of the cylinder assembly. For example, the first fuel conduit portion of the fuel injector mounting assembly coaxially aligns a longitudinal axis of the fuel injector with both a longitudinal axis of the first fuel conduit portion and a longitudinal axis defined by the fuel manifold. By controlling the angular position of the fuel injector relative to the fuel manifold of the cylinder assembly, the fuel injector mounting assembly allows for adequate dispersion and atomization of the fuel provided to each cylinder assembly.
In one arrangement, a fuel injector mounting assembly includes a base configured to mount to a cylinder assembly and a fuel conduit supported by the base. The fuel conduit includes a first fuel conduit portion having a first port operable to couple to a fuel source end of a fuel injector and a second fuel conduit portion in fluid communication with the first fuel conduit portion, the second fuel conduit portion having a second port operable to couple to a fuel source. The fuel injector mounting assembly is configured to capture the fuel injector between the first fuel conduit portion and a fuel manifold of the cylinder assembly. In such an arrangement, both ends of the fuel injector are secured to the cylinder assembly to minimize any relative motion in the fuel injector's seals relative to the cylinder assembly's fuel manifold.
In one arrangement, a cylinder assembly includes a cylinder housing, a fuel injector having a fuel source end and a nozzle end opposing the fuel source end, the nozzle end being carried by a fuel manifold of the cylinder housing, and a fuel injector mounting assembly. The fuel injector mounting assembly includes a base supported by the cylinder housing and a fuel conduit supported by the base. The fuel conduit includes a first fuel conduit portion having a first port coupled to the fuel source end of the fuel injector and a second fuel conduit portion in fluid communication with the first fuel conduit portion, the second fuel conduit portion having a second port operable to couple to a fuel source. The fuel injector mounting assembly is configured to capture the fuel injector between the first fuel conduit portion and the fuel manifold of the cylinder housing.
In one arrangement, a method for securing fuel injector to an aircraft engine cylinder assembly includes disposing a nozzle end of a fuel injector within a fuel manifold of a cylinder housing of aircraft cylinder assembly, disposing a fuel source end within a first port of a first fuel conduit portion of a fuel injector mounting assembly, and securing a base of the fuel injector mounting assembly to the cylinder assembly.
In one arrangement, an engine includes an engine body, a network of fuel lines, and multiple cylinder assemblies supported by the engine body and coupled to the network of fuel lines. Each cylinder assembly includes a cylinder housing, fuel injector mounting assembly coupled to the cylinder housing, a cylinder assembly fitting portion coupled to the cylinder housing, a fuel injector supported between the fuel injector mounting assembly and the cylinder assembly fitting portion, fuel injector including a nozzle end adjacent the cylinder assembly fitting portion and a fuel source end adjacent the fuel injector mounting assembly, and a fuel line connector supported by the fuel injector mounting assembly. The fuel line connector is constructed and arranged to couple to a particular fuel line of the network of fuel lines.
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 relate to a fuel injector mounting assembly for an aircraft engine fuel delivery system. The fuel injector mounting assembly is configured to limit or constrain movement of a fuel injector relative to a corresponding cylinder assembly. For example, the fuel injector mounting assembly includes a base that is secured to a cylinder assembly's housing and a fuel conduit. The fuel conduit includes a first fuel conduit portion which operates in conjunction with a cylinder assembly's fuel manifold to capture a fuel injector between the fuel injector mounting assembly and the cylinder assembly's fuel manifold. The fuel conduit also includes a second fuel conduit portion which is secured to a compliant fuel line. With such a configuration of the fuel injector mounting assembly, both ends of the fuel injector are secured to the cylinder assembly to minimize any relative motion in the fuel injector's seals relative to either the cylinder assembly's fuel manifold or to the compliant fuel line. In one arrangement, the fuel injector mounting assembly controls the angular position of the fuel injector relative to a fuel manifold of the cylinder assembly. For example, the first fuel conduit portion of the fuel injector mounting assembly coaxially aligns a longitudinal axis of the fuel injector with both a longitudinal axis of the first fuel conduit portion and a longitudinal axis defined by the fuel manifold. By controlling the angular position of the fuel injector relative to the fuel manifold of the cylinder assembly, the fuel injector mounting assembly allows for adequate dispersion and atomization of the fuel provided to each cylinder assembly.
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 line 80 includes a set of fuel line conduits 82, such as first and second fuel line conduits 82-1, 82-2, a fuel inlet 88, and a fuel outlet 90 interconnected by a set of fuel line connectors 84 such as connectors 84-1 through 84-3. Each of the first and second fuel line conduits 82-1, 82-2, fuel inlet 88, and fuel outlet 90 are configured as generally tubular structures configured to carry fuel between the fuel source 92 and a fuel pressure regulator 96. The fuel line conduits 82-1, 82-2 are coupled to the fuel line connectors 84-1 through 84-3 and provide fluid communication between the fluid inlet 88 and the fluid outlet 90. For example, the first fuel line conduit 82-1 is coupled between the first fuel line connector 84-1 and the second fuel line connector 84-2 while the second fuel line conduit 82-2 is coupled between the second fuel line connector 84-2 and the third fuel line connector 84-2. The fuel inlet 88 is disposed in fluid communication between the third fuel line connector 84-2 and a fuel pump 94 while the fuel outlet 90 is disposed in fluid communication with the first fuel line connector 84-1 and the fuel pressure regulator 96. The combination of the fuel lines 80, 80′ with the fuel pump 94, fuel pressure regulator 96 and the fuel source 92 forms a fluid circuit 98 as indicated in
Each fuel line connector 84-1 through 84-3 is disposed in fluid communication with a fuel injector 102, such as low-pressure automotive style fuel injectors, for provision of fuel to each corresponding cylinder assembly 60. For example, as illustrated in
The fuel line 80 is configured to allow relative motion of the cylinder assemblies 60 during operation while minimizing the application of excessive loads on portions of the fuel line 80. In one arrangement, each of the first and second fuel line conduits 82-1, 82-2 is formed from a compliant material such as a compliant metal material or a compliant rubber or polymeric material. The compliant fuel line conduits 82-1, 82-2 are configured to absorb at least a portion of a load generated by the cylinder assemblies 60 on the fuel line 80 during operation. Typically in use, an operational cylinder assembly 60 causes the crankcase housing 58 to flex or bend that in turn causes each cylinder assembly 60 to move relative to the fuel line conduits 82. For example, with particular reference to the cylinder assembly 60-2 as shown in
In use, the fuel pump 94 withdraws fuel from a fuel source 92 and delivers the fuel under pressure to the fuel line 80 via the fuel inlet 88. As the fuel flows from the fuel inlet 88 to the fuel outlet 90, each of the fuel line connectors 84-1 through 84-3 provide fuel to a corresponding cylinder assembly 60-1 through 60-3, via corresponding fuel injectors 102. The fuel pressure regulator 96 receives unused fuel received from the fuel outlet 90 and delivers the unused fuel to the fuel source 92.
As indicated above, each fuel line connector 84 is disposed in fluid communication with a corresponding cylinder assembly 60 by way of a fuel injector 102. In one arrangement, in order to maintain an adequate seal between each fuel injector and a corresponding cylinder assembly, thereby allowing the use of fuel injectors as part of a piston aircraft engine 50, the engine includes a fuel injector mounting assembly 100 used to substantially constrain movement of a fuel injector's seals relative to a corresponding cylinder assembly. A description of an arrangement of the fuel injector mounting assembly 100 is provided with respect to
The fuel injector mounting assembly 100 includes a base 110 and a fuel conduit 112 supported by the base 110. The base 110 is configured to mount to a cylinder assembly 60, such as cylinder assembly 60-1 shown in
The fuel conduit 112 is supported by the base 110 and is configured to direct fuel from a fuel line connector 84 to a corresponding fuel injector 102. As illustrated in
In one arrangement, the fuel injector mounting assembly 100 controls the angular position of the fuel injector 102 relative to a fuel manifold of the cylinder assembly. For example, with reference to
In use, the fuel injector mounting assembly 100 is configured to capture a fuel injector 102 between the first fuel conduit portion 116 and a fuel manifold 148 of a cylinder assembly 60. For example, during assembly an assembler disposes a nozzle end 148 of the fuel injector 102 within a fuel manifold 148 of a cylinder housing of aircraft cylinder assembly. In one arrangement, the fuel manifold 148 is sized such that the interaction between the nozzle end 150 and the fuel manifold 148 compresses a compliant O-ring 152 disposed at the nozzle end 150. This interaction seals the nozzle end 150 with the fuel manifold 148 to minimize or prevent leakage of fuel from the fuel manifold 148. The assembler then disposes the fuel source end 120 of the fuel injector 102 within a first port 118 of the first fuel conduit portion 116 of the fuel injector mounting assembly 100. The assembler then secures the base 110 of the fuel injector mounting assembly 100 to the cylinder assembly. For example, as described above, the manufacturer can utilize fasteners to secure the base to the cylinder assembly housing 62. With such a configuration of the fuel injector mounting assembly 100, both ends 150, 120 of the fuel injector 102 are secured to the cylinder assembly 60 thereby minimizing any relative motion of the fuel injector's seals 122, 152 relative to either the cylinder assembly's fuel manifold 148 or to the compliant fuel line 80. Accordingly, the fuel injector mounting assembly 100 minimizes leakage of fuel from the fuel injector 102 during operation.
As indicated above, the fuel manifold 148 is sized such that the interaction between the nozzle end 150 and the fuel manifold 148 compresses a compliant O-ring 152 disposed at the nozzle end 150 of the fuel injector 102. In certain cases, however, the port diameter of an engine's fuel manifold 148 can be smaller than outer diameter of the nozzle end 150 of the fuel injector 102. In one arrangement, to allow the use of the fuel injectors with such fuel manifolds, the fuel injector mounting assembly 100 includes a cylinder assembly fitting portion 160, as illustrated in
In use, an assembler inserts the manifold mounting portion 164 within the fuel manifold 148 to create a substantially fluid-tight seal. With such insertion, the longitudinal axis 168 of the cylinder assembly fitting portion 160 is substantially coaxially aligned with the longitudinal axis 142 of the first fuel conduit portion 116 to allow for adequate dispersion and atomization of the fuel by the fuel injector 102. The assembler then inserts the nozzle end 150 of the fuel injector 102 within the fuel injector mounting portion 162 to compress the O-ring 152 disposed at the nozzle end 150 thereby minimizing or preventing leakage of fuel from the cylinder assembly fitting portion 160 during operation.
As described above, each cylinder assembly 60 includes a corresponding fuel injector 102 configured to deliver fuel from a fuel source 92 to the cylinder assembly. In use, and with reference to
While the securing mechanism 170 can be configured in a variety of ways, in one arrangement and as indicated in
When disposed within the fuel injector mounting assembly 100, the fuel injector 102 can rotate about its longitudinal axis 140. Such rotation can place a strain on electrical connectors coupled to the fuel injector's electrical coupling port 169. To minimize such rotation, in one arrangement, the fuel injector mounting assembly 100 includes a securing mechanism 170 configured to limit rotation of the fuel injector 102 about its longitudinal axis 140. For example, as indicated in
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 fuel injectors 102 and the fuel injector mounting assemblies 100 are utilized with an engine 50 having compliant fuel lines 80, 80′. Such indication is by way of example only. In one arrangement, the fuel injectors 102 and the fuel injector mounting assemblies 100 can be used with an engine having a fuel distribution assembly that includes a hub, connector tubes, and fuel nozzles, such as shown and described with respect to
As indicated above, the each of the first and second fuel line conduits 82-1, 82-2 is formed from a compliant material such as a rubber material to allow relative motion of the cylinder assemblies 60 during operation while minimizing the application of excessive loads on portions of the fuel line 80. Such description is by way of example only. In one arrangement, one or more of the fuel line connectors 84 are configured to allow relative motion of the cylinder assemblies 60 during operation. For example, as indicated in
As indicated above, in one arrangement, each of the first and second fuel line conduits 82-1, 82-2 is formed from a compliant material such as a compliant metal material or a compliant rubber or polymeric material. In one arrangement, the fuel inlet 88 and fuel outlet 90 are also formed from a compliant material such as a compliant metal material or a compliant rubber or polymeric material.
This patent application claims the benefit of U.S. 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.
Number | Date | Country | |
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60926038 | Apr 2007 | US |