Patent Description:
In many fuel delivery systems, the main pump is not optimized for the entire operating range, which results in waste power and excess heat. The main pump is generally oversized to pump suitable fuel at low speeds, which generally requires the pump to be heavier and larger than is strictly necessary.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved fuel pump systems. The present disclosure provides a solution for this need. <CIT> describes a fuel pumping unit.

A fuel pump system according to claim <NUM> includes an inlet line and a motorized pump having a motorized pump inlet in fluid communication with the inlet line to receive fuel from the inlet line, and a motorized pump outlet configured to output flow from the motorized pump. The system includes a first selector valve in fluid communication with the inlet line at a first inlet port. The first selector valve is in fluid communication with the motorized pump outlet via a first outlet branch at a second inlet port to receive fuel from the motorized pump outlet. The first selector valve is configured to selectively communicate the first inlet port to an outlet port, and to selectively communicate the second inlet port to the outlet port. The system also includes a main fuel pump having a main fuel pump inlet in fluid communication with the first selector valve to be downstream of the first selector valve, and having a main fuel pump outlet. The system includes a second selector valve in fluid communication with the main fuel pump outlet at a first input port. The second selector valve is in fluid communication with the motorized pump outlet via a second outlet branch at a second input port to receive fuel from the motorized pump outlet. The second selector valve is configured to selectively communicate the first input port to an output port, and to selectively communicate the second input port to the output port. The output port is in fluid communication with an outlet line.

In certain embodiments, the first selector valve is actively controlled. For example, in certain embodiments, the first selector valve can be a solenoid valve.

In certain embodiments, the second selector valve can be a passive valve such that the second selector valve can be configured to selectively communicate the first input port to an output port when a pressure from the main fuel pump exceeds a pressure from the motorized fuel pump or exceeds a set threshold. In certain embodiments, each selector valve is a three-way valve.

The system can include a controller configured to control a motor connected to the motorized pump to drive the motorized pump. The controller can be configured to operate the first selector valve to select whether the first inlet port is in communication with the outlet port, or whether the second inlet port is in communication with the outlet port. In certain embodiments, the controller can be configured to operate the motor and the first selector valve to provide a plurality of modes. The plurality of modes can include a low flow mode where only the motorized pump provides flow to the outlet line, a mid-flow mode where only the main fuel pump provides flow to the outlet line, and a high flow mode where both the motorized pump and the main fuel pump are operated in series to provide flow to the outlet line.

In certain embodiments, the main fuel pump can be a centrifugal pump. The motorized pump can also be a centrifugal pump, for example. Any suitable pump types are contemplated herein.

In accordance with at least one aspect of this disclosure, an aircraft comprises a fuel pump system according to claim <NUM>.

In accordance with at least one aspect of this disclosure, a fuel pump system according to claim <NUM> comprises first and second selector valves configured to allow flow through only the motorized pump to bypass the main fuel pump to the outlet line in low flow mode, to allow flow through only the main fuel pump to bypass the motorized pump to the outlet line in a mid-flow mode, and to allow flow through the motorized pump to output to an inlet of the main fuel pump to then output from the main fuel pump to the outlet line in a high flow mode.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a system in accordance with the disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments and/or aspects of this disclosure are shown in <FIG>.

According to the invention, referring to <FIG>, a fuel pump system <NUM> includes an inlet line <NUM>. The system <NUM> also includes a motorized pump <NUM> having a motorized pump inlet 103a in fluid communication with the inlet line <NUM> (e.g., via a first inlet branch <NUM>) to receive fuel from the inlet line <NUM>, and a motorized pump outlet 103b configured to output flow from the motorized pump <NUM>.

The system <NUM> includes a first selector valve <NUM> in fluid communication with the inlet line <NUM> (e.g., via a second inlet branch <NUM>) at a first inlet port 107a. The first selector valve <NUM> is in fluid communication with the motorized pump outlet 103b via a first outlet branch <NUM> at a second inlet port 107b to receive fuel from the motorized pump outlet 103b. The first selector valve <NUM> is configured to selectively communicate the first inlet port 107a to an outlet port 107c, and to selectively communicate the second inlet port 107b to the outlet port 107c.

The system <NUM> also includes a main fuel pump <NUM> having a main fuel pump inlet 113a in fluid communication with the first selector valve <NUM> to be downstream of the first selector valve <NUM>, and having a main fuel pump outlet 113b. The system <NUM> includes a second selector valve <NUM> in fluid communication with the main fuel pump outlet 113b at a first input port 115a. The second selector valve <NUM> is in fluid communication with the motorized pump outlet 103b via a second outlet branch <NUM> at a second input port 115b to receive fuel from the motorized pump outlet 103b. The second selector valve <NUM> is configured to selectively communicate the first input port 115a to an output port 115c, and to selectively communicate the second input port 115b to the output port 115c. The output port 115c can be in fluid communication with an outlet line <NUM>.

In certain embodiments, the first selector valve <NUM> can be actively controlled. For example, in certain embodiments, the first selector valve <NUM> can be a solenoid valve (e.g., driven by a solenoid <NUM> as shown). Any other suitable controllable valve (e.g., via hydraulics) and/or any suitable passive valve configured to function as disclosed herein is contemplated herein.

In certain embodiments, the second selector valve <NUM> can be a passive valve such that the second selector valve <NUM> can be configured to selectively communicate the first input port 115a to the output port 115c when a pressure from the main fuel pump <NUM> exceeds a pressure from the motorized fuel pump <NUM> or exceeds a set threshold (to cause the selector valve <NUM> to shut off flow from the motorized pump <NUM> to the outlet line <NUM> and to allow flow from the main pump <NUM> to flow to the outlet line <NUM>). The second selector valve <NUM> can be any suitable valve type (e.g., passive or active). In certain embodiments, each selector valve <NUM>, <NUM> can be a three-way valve.

The system <NUM> can include a controller <NUM> configured to control a motor <NUM> (e.g., an electric motor) connected to the motorized pump <NUM> to drive the motorized pump <NUM>. The controller <NUM> can be configured to operate the first selector valve <NUM> (e.g., by controlling solenoid <NUM>) to select whether the first inlet port 107a is in communication with the outlet port 107c, or whether the second inlet port 107b is in communication with the outlet port 107c. The controller <NUM> can include any suitable hardware and/or software module(s) configured to perform an suitable function disclosed herein, e.g., as described above and below.

In certain embodiments, the controller <NUM> can be configured to operate the motor <NUM> and the first selector valve <NUM> to provide a plurality of modes, e.g., referring additionally to <FIG>. The plurality of modes can include a low flow mode (e.g., for start to sub-idle flow as shown in <FIG>) where only the motorized pump <NUM> provides flow to the outlet line <NUM>, a mid-flow mode (e.g., for sub-idle to climb flow as shown in <FIG>) where only the main fuel pump <NUM> provides flow to the outlet line <NUM> (e.g., and the motor <NUM> can be depowered), and a high flow mode (e.g., for take-off flow as shown in <FIG>) where both the motorized pump <NUM> and the main fuel pump <NUM> are operated in series to provide flow to the outlet line <NUM> (e.g., which can be connected to a combustor of a turbomachine). Any other suitable mode(s) is/are contemplated herein.

In certain embodiments, the main fuel pump <NUM> can be a centrifugal pump. The motorized pump <NUM> can also be a centrifugal pump, for example. Any suitable pump types are contemplated herein. Centrifugal pumps can be, smaller, lighter, stronger, and more efficient than certain other pumps, which can be beneficial (e.g., for aircraft systems).

In certain embodiments, a boost pump <NUM> can be upstream of the inlet line <NUM> (e.g., and connected to a fuel supply) to provide boost pressure to the pump <NUM>, <NUM>, for example. Any other suitable flow devices and/or components in the system <NUM> are contemplated herein.

In accordance with at least one aspect of this disclosure, an aircraft (not shown) includes a fuel pump system <NUM> according to claim <NUM>.

In accordance with at least one aspect of this disclosure, a fuel pump system <NUM> according to claim <NUM> includes first and second selector valves <NUM>, <NUM> configured to allow flow through only the motorized pump <NUM> to bypass the main fuel pump <NUM> to the outlet line <NUM> in a low flow mode (e.g., as shown in <FIG>), to allow flow through only the main fuel pump <NUM> to bypass the motorized pump <NUM> to the outlet line <NUM> in a mid-flow mode (e.g., as shown in <FIG>), and to allow flow through the motorized pump <NUM> to output to an inlet 113a of the main fuel pump <NUM> to then output from the main fuel pump <NUM> to the outlet line <NUM> in a high flow mode (e.g., as shown in <FIG>).

Embodiments can include a fail-safe setting such that the first selector valve <NUM> and second selector valve <NUM> are configured to communicate the main pump <NUM> with the outlet line <NUM> in a failure state. Thus, the valves can fail to allow main pump flow (e.g., as shown in <FIG> and/or <FIG>).

Embodiments can include an electric start and high power assistance pump system. In certain embodiments, through the use of two selector valves (e.g., one active and one passive) the pump providing flow to a fuel control valve can be switched or combined. First, an electric motorized pump can be engaged for engine start to sub-idle speeds (e.g., the main pump driven by the engine being bypassed), and at a designated sub-idle speed the main pump can generate sufficient pressure to shuttle a passive selector valve to select the main pump as the fuel source and the electric motorized pump can be depowered. The main pump can support the flow requirements up to cruise or climb power levels, for example. Above this, the electric motorized pump can be re-engaged and the active selector valve can be switched to put the main pump and electric motorized pump in series. The electric motorized pump can boost the inlet pressure to the main pump to support the engine for climb and/or take-off power levels.

Embodiments provide improvements over single gear pump systems (main/servo flow) and twin gear pump systems (separate main and servo or pairable pumps), for example. Embodiments can enable increased main pump efficiency, reduced power extraction, reduced fuel temp rise, elimination of bypass flow, reduced IFPC size/weight, improved TSFC at cruise, and improved contamination resistance (e.g., due to centrifugal pump use). Embodiments can also provide improvements over a dual centrifugal pump system by providing increased main pump efficiency, reduced power extraction and TSFC a cruise, reduced fuel temp rise, and reduced IFPC size/weight.

Aspects of this disclosure may be described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of this disclosure. It will be understood that each block of any flowchart illustrations and/or block diagrams, and combinations of blocks in any flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in any flowchart and/or block diagram block or blocks.

Any suitable combination(s) of any disclosed embodiments and/or any suitable portion(s) thereof are contemplated herein as appreciated by those having ordinary skill in the art in view of this disclosure.

Claim 1:
A fuel pump system (<NUM>), comprising:
an inlet line (<NUM>);
a motorized pump (<NUM>) having a motorized pump inlet (103a) in fluid communication with the inlet line (<NUM>) to receive fuel from the inlet line (<NUM>), and a motorized pump outlet (103b) configured to output flow from the motorized pump (<NUM>);
a first selector valve (<NUM>) in fluid communication with the inlet line (<NUM>) at a first inlet port (107a), wherein the first selector valve (<NUM>) is in fluid communication with the motorized pump outlet (103b) via a first outlet branch (<NUM>) at a second inlet port (107b) to receive fuel from the motorized pump outlet (103b), wherein the first selector valve (<NUM>) is configured to selectively communicate the first inlet port (107a) to an outlet port (107c), and to selectively communicate the second inlet port (107b) to the outlet port (107c);
a main fuel pump (<NUM>) having a main fuel pump inlet (113a) in fluid communication with the first selector valve (<NUM>) to be downstream of the first selector valve (<NUM>), and having a main fuel pump outlet (113b); and
a second selector valve (<NUM>) in fluid communication with the main fuel pump outlet (113b) at a first input port (115a), wherein the second selector valve (<NUM>) is in fluid communication with the motorized pump outlet (103b) via a second outlet branch (<NUM>) at a second input port (115b) to receive fuel from the motorized pump outlet (103b), wherein the second selector valve (<NUM>) is configured to selectively communicate the first input port (115a) to an output port (115c), and to selectively communicate the second input port (115b) to the output port (115c), wherein the output port (115c) is in fluid communication with an outlet line (<NUM>).