(19)
(11)EP 3 022 426 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
02.09.2020 Bulletin 2020/36

(21)Application number: 14826768.5

(22)Date of filing:  18.07.2014
(51)International Patent Classification (IPC): 
F02C 9/28(2006.01)
F02C 7/232(2006.01)
F02C 7/22(2006.01)
F02C 9/26(2006.01)
(86)International application number:
PCT/US2014/047217
(87)International publication number:
WO 2015/010033 (22.01.2015 Gazette  2015/03)

(54)

SERIES PLUS PARALLEL METERING PRESSURE REGULATION SYSTEM FOR A THERMAL EFFICIENT FUEL METERING SYSTEM

REIHEN- UND PARALLELMESSDRUCKREGLERSYSTEM FÜR EIN THERMISCHES EFFIZIENTES KRAFTSTOFFMESSSYSTEM

SYSTÈME DE RÉGULATION DE PRESSION DE DOSAGE PARALLÈLE EN SÉRIE POUR UN SYSTÈME DE DOSAGE DE COMBUSTIBLE EFFICACE THERMIQUEMENT


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 19.07.2013 US 201313946096

(43)Date of publication of application:
25.05.2016 Bulletin 2016/21

(73)Proprietor: Woodward, Inc.
Fort Collins, Colorado 80524 (US)

(72)Inventor:
  • BAKER, Carthel C.
    Oregon, Illinois 61061 (US)

(74)Representative: Conroy, John 
Fish & Richardson P.C. Highlight Business Towers Mies-van-der-Rohe-Straße 8
80807 München
80807 München (DE)


(56)References cited: : 
EP-A2- 0 050 403
US-A1- 2003 192 300
US-A1- 2010 122 535
US-A- 6 095 793
US-A1- 2010 089 025
US-A1- 2010 263 634
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF THE INVENTION



    [0001] This invention generally relates to fuel flow systems, and more particularly to parallel metering fuel flow systems in combustion engine applications.

    BACKGROUND OF THE INVENTION



    [0002] Parallel metering systems have been used in many industrial turbine applications. These systems provide accurate fuel placement to multiple combustor locations via multiple metered flow paths arranged in parallel. In such systems, flow is initially provided by one or more pumps. This initial flow is then divided across the multiple metered flow paths arranged in parallel to distribute the same to multiple combustor locations.

    [0003] As commercial aircraft combustion systems become more complex in order to provide improved fuel efficiency and reduced emissions, the flexibility of a parallel metering system may offer significant benefits. Positive displacement pumps are often preferred for turbine engines due to their good efficiency and high reliability. Parallel metering systems used in industrial turbine engine applications typically include a pressure regulated positive displacement pump that supplies flow to the multiple metered flow paths arranged in parallel. The pump pressure regulation system typically maintains the pump discharge pressure at a constant pressure that is high enough to meet the pressure needs of the metered flow paths for all operating conditions.

    [0004] Unfortunately, this discharge pressure may be significantly higher than the requirements of the metered flow path. Operating the pump at pressures higher than required leads to undesirable additional pump heat input to the fuel system. Thermal efficient fuel pumping is typically required to meet the aircraft engine operational requirements. Maintaining the positive displacement pump at high pressure for all operating conditions is likely not acceptable for most aircraft engine applications.

    [0005] Accordingly, there is a need in the art for a parallel metering system that does not require substantially over-sizing the pump and its attendant discharge pressure in an effort to accommodate various systemic pressure demands.

    [0006] The invention provides such a parallel metering system. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

    [0007] US 2010/0263634 describes a system and method that provide dual level pressurization control of a fuel supply system based on whether fuel is being supplied to one or more secondary fuel loads.

    [0008] US 2003/0192300 describes a system for controlling the flow of fuel to a gas turbine engine is operable in at least two modes.

    [0009] US 2010/0122535 describes a fuel controller for a combustion system in a gas turbine. US 2010/0089025 describes a fuel delivery and control system that includes a dual pump fluid circuit configuration.

    [0010] US 6,095,793 describes a dynamic control system and method for catalytic combustion process and gas turbine engine utilizing the same.

    [0011] EP0050403 describes a fuel-supply control system for a gas-turbine engine.

    BRIEF SUMMARY OF THE INVENTION



    [0012] The above referenced issues are overcome by including a single bypassing metering system in series with a parallel metering system that includes a primary regulated circuit in parallel with at least two secondary metering circuits. A parallel pressure regulator in the primary regulated circuit of the parallel metering system is referenced to each secondary metering circuit and acts to ensure that sufficient pressure is maintained to supply each secondary metering circuit. The single bypassing metering system upstream of the parallel system meters total fuel flow that is sent to the parallel metering system. The single bypassing fuel metering system regulates the pump discharge pressure to a sufficient pressure to supply the metering and combustion systems by the bypassing positive displacement pump flow in excesses of the system flow demand back to the low pressure inlet of the pump.

    [0013] In one aspect, an engine fuel system according to claim 1 is provided. The engine fuel system includes a supply arrangement including at least one pump for providing an outlet flow of fuel. The system also includes a bypass metering system in fluid communication with the supply arrangement that includes a fuel metering valve and a bypass regulator in fluid communication with an inlet of the fuel metering valve and an inlet of the at least one pump. The bypass regulator is operable to bypass at least a portion of the outlet flow of fuel from the at least one pump back to the inlet of the at least one pump. The system also includes a parallel metering system including a primary regulated circuit and at least two secondary metering circuits arranged in parallel with the primary regulated circuit. The parallel metering system is in fluid communication with the bypass metering system such that it receives a metered flow of fuel from the fuel metering valve of the bypass metering system. The primary regulated circuit includes a parallel pressure regulator that is operably connected to the primary regulated circuit and the at least two secondary metering circuits to detect a pressure in each of the primary and at least two secondary metering circuits.

    [0014] In certain embodiments, the at least one pump of the supply arrangement is a positive displacement pump. In certain embodiments, the at least one pump of the supply arrangement includes two pumps in parallel with one another, and also includes a pump switching system operably connected to each of the two pumps, the pump switching system operable to combine or switch between outlet flows from each of the two pumps to provide the outlet flow of the supply arrangement. The two pumps may each be positive displacement pumps.

    [0015] In certain embodiments, the bypass regulator is operably connected to an outlet of the fuel metering valve of the bypass metering system to detect a pressure of the metered flow of fuel from the fuel metering valve.

    [0016] Each of the at least two secondary metering circuits include a fuel metering valve and a throttling valve operably connected to an inlet and an outlet of the fuel metering valve to maintain a substantially constant pressure differential across the fuel metering valve. The parallel pressure regulator is operably connected to the at least two secondary metering circuits downstream from the throttling valve.

    [0017] In certain embodiments, each of the at least two secondary metering circuits include the fuel metering valve and a head regulator operably connected to an inlet and an outlet of the fuel metering valve, and further comprises the throttling valve connected to the outlet of the fuel metering valve and the head regulator to maintain a substantially constant pressure differential across the fuel metering valve.

    [0018] In certain embodiments, the system also includes a pressurizing and shutoff valve arranged such that the metered flow of fuel from fuel metering valve is directed through the pressurizing and shutoff valve prior to being received by the parallel metering system.

    [0019] The bypass regulator in fluid communication with an inlet of the fuel metering valve and an inlet of the at least one pump is operably connected to detect a pressure of the metered flow of fuel from the fuel metering valve. In certain embodiments, the bypass metering system is operably connected to an outlet of the fuel metering valve to detect a pressure at the outlet of the fuel metering valve, and the bypass regulator is operable to maintain a substantially constant pressure differential across the fuel metering valve. The parallel pressure regulator is operable to set an inlet side pressure of the parallel pressure regulator at least as high as a highest one of the detected pressures of the primary and at least two secondary metering circuits, plus a regulated pressure value of the parallel pressure regulator.

    [0020] In certain embodiments, the fuel metering valve is operable to adjust the metered flow of fuel in response to a change in the inlet side pressure of the parallel pressure regulator.

    [0021] In yet another aspect, a method according to claim 10 for managing a flow of fuel in an engine fuel system having a parallel metering system that includes a primary regulated circuit and at least one secondary metering circuit is provided. The method includes the step of providing a metered flow of fuel to the parallel metering circuit, the metered flow of fuel divided between the primary regulated circuit and at least one secondary metering circuit. The method also includes the step of detecting, with a parallel pressure regulator of the primary regulated circuit, a downstream pressure of the primary regulated circuit and a downstream pressure of the at least two secondary metering circuits. The method also includes the step of adjusting an inlet side pressure of the parallel pressure regulator to be at least as high as a highest one of the detected downstream pressures of the primary regulated circuit and the at least two secondary metering circuits, plus a regulated pressure value of the parallel pressure regulator. The method also includes the step of detecting, with a bypass regulator of a bypass metering system in fluid communication with the parallel metering system, the adjusted inlet side pressure of the parallel pressure regulator. The method also includes the step of adjusting an inlet pressure of a flow of fuel to a fuel metering valve of the bypass metering system using the bypass regulator to maintain a substantially constant pressure differential across the fuel metering valve.

    [0022] In certain embodiments, the method includes the step of adjusting an outlet flow of fuel from the fuel metering valve in response to the adjusted inlet side pressure of the parallel pressure regulator.

    [0023] In certain embodiments, the step of adjusting the pressure of the flow of fuel to the fuel metering valve includes bypassing a portion of an outlet flow of fuel from a positive displacement pump back to an inlet of the positive displacement pump.

    [0024] Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0025] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

    FIG. 1 is a schematic representation of one embodiment of a system according to the teachings of the present invention;

    FIG. 2 is a schematic representation of the system of FIG. 1, incorporating additional secondary metering circuits;

    FIG. 3 is a schematic representation of another embodiment of a system according to the teachings of the present invention which includes a dual pump supply arrangement which utilizes a pump switching system; and

    FIG. 4 is a schematic representation of another embodiment of a system according to the teachings of the present invention which includes at least on secondary metering circuit that employs a head regulator.



    [0026] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the scope of the invention as defined by the appended claims.

    DETAILED DESCRIPTION OF THE INVENTION



    [0027] Turning now to the drawings, FIG. 1 illustrates a first exemplary embodiment of a series plus parallel metering pressure regulation system 100. System 100 includes a supply arrangement 102 that supplies a flow of fuel at pressure P1 to a bypass metering system 104. Bypass metering system 104 in turn provides a metered flow of fuel at pressure P2 to a pressurizing and shutoff valve (PSV) 106. Fuel from PSV 106 is received by a parallel metering system 108 that is downstream from PSV 106 as shown for ultimate delivery to various locations in a combustion engine.

    [0028] Supply arrangement includes a boost pump 110 that provides an initial flow of fuel to a positive displacement pump 112 of supply arrangement 102. Flow delivered to the inlet side of pump 112 is at pressure Pb. Flow from pump 112 is at pressure Ps. Some of this flow is utilized for actuation supply 114 at pressure Psf, with remainder being supplied to the bypass metering system at pressure P1.

    [0029] Bypass fuel metering system 104 includes a fuel metering valve (FMV) 116 that provides a metered flow of fuel as governed by electro-hydraulic servo valve (EHSV) 118. Bypass fuel metering system 104 also includes a bypass regulator (BPR) 120 that is operably connected to an outlet side of FMV 116 to sense pressure P2, i.e. the pressure of the outlet flow of fuel from FMV 116. BPR 120 may be a proportional, integral, or integral plus proportional control device.

    [0030] Bypass metering system 104 regulates pump 112 discharge pressure P1 to a sufficient pressure to supply parallel metering system 108 and actuation supply 114 by bypassing pump 112 flow in excess of the necessary parallel metering system 108 flow demand back to the low pressure inlet side of pump 112. BPR 120 senses both the pressure at the inlet and at the discharge of FMV 116 (PI and P2). BPR 120 acts to regulate P1 to a nearly constant value above P2 by controlling the portion of total pump 112 flow that is allowed to be bypassed back to the low pressure side of pump 112. With the differential pressure (P1 - P2) regulated to a nearly constant, the amount of metered flow delivered to parallel metering system 108 becomes directly a function of open FMV 116 port area. Open port area is a function of FMV 116 position, which is fed back to the electronic control system as LVDT position. FMV 116 is positioned to provide the desired open port area by EHSV 118.

    [0031] Parallel metering system 108 includes a primary regulated circuit 122, and first and second secondary metering circuits 124, 126 arranged in parallel with one another and in parallel with primary regulated circuit 122. Primary regulated circuit 122 and secondary metering circuits 124, 126 divide an input flow of fuel provided by bypass metering system 104.

    [0032] Primary regulated circuit 122 includes a parallel pressure regulator (PPR) 128 which may be a proportional, integral, or integral plus proportional control device. Secondary metering circuits 124, 126 each include a FMV 136 that provides a metered flow of fuel as governed by EHSV 138. Additionally, a throttling valve (THV) 140 is connected at an outlet side of FMV 136 as illustrated. THV 140 is responsible for regulating the pressure differential across each FMV 136 to a nearly constant value by acting as a variable restriction in series with FMV 136. THV 140 may be a proportional, integral, or proportional plus integral control device.

    [0033] PPR 128 is connected to each of primary regulated circuit 122 and secondary metering circuits 124, 126 to sense the pressure downstream of each of the three circuits 122, 124, 126. More specifically, PPR senses the downstream pressure P-Pn of primary regulated circuit, the downstream pressure SM1-Pn of first secondary metering circuit 124, and the downstream pressure SM2-Pn of second secondary metering circuit 126. Secondary metering circuits 124, 126 each have a specific required minimum operational pressure differential across the same. PPR 128 maintains the pressure upstream therefrom at PM-P1 at a pressure sufficient enough to maintain the minimum operational pressure differential across each secondary metering circuit 124, 126.

    [0034] More specifically, because PPR 128 is connected to the downstream pressures P-Pn, SM1-Pn, SM2-Pn, of each circuits 122, 124, 126, it is operable to set PM-P1 equal to the highest of these values, plus an internal regulated pressure of PPR 128. More specifically, PPR 128 will have its own internal regulated pressure value that is added to the highest of P-Pn, SM1-Pn, SM2-Pn to generate the inlet side pressure value PM-P1. In other words, PPR 128 inherently requires a minimum pressure in primary regulated circuit 122 to overcome the regulated pressure value of PPR 128 to hold PPR 128 in an open position relative to primary regulated circuit 122. However, PPR 128 is also connected to secondary metering circuits 124, 126 such that it receives pressures SM1-Pn, SM2-Pn. As a result, to maintain PPR 128 in an open position, the pressure in primary regulated circuit 122 at PPR 128 must be greater than the regulated pressure value plus pressure SM1-Pn, or greater than the regulated pressure value plus pressure SM2-Pn. One example of such a configuration may be a proportional valve biased to a closed condition by its internal spring to close primary regulated circuit 122. Along with this spring force, the pressure SM1-Pn from secondary metering path 124 may also bias this valve closed. As such, the effective pressure at PPR 128 is this pressure SM1-Pn, plus the pressure derived from the internal spring force. A duplicate configuration would also be used for secondary metering path 126. When the pressure in primary regulated circuit 122 is greater than SM1-Pn plus the regulated pressure value and SM2-Pn plus the internal regulated pressure value, the above referenced proportional valves are held open. However, as either of SM1-Pn plus the regulated pressure value, or SM2-Pn plus the regulated pressure valve approach the pressure of in primary regulated circuit 122, this pressure will be reflected at the inlet side of PPR 128.

    [0035] As one example of such a configuraiton, PPR 128 may have a regulated pressure value of 0.2 MPa (30 psi). In other words, PPR 128 may provide a 0.2 MPa (30 psi) pressure differential thereacross, simply by its design by way of the spring force used to hold the proportional valve connected between primary regulated circuit 122 and secondary metering circuit 124, as well as the proportional valve connected between primary regulated circuit 122 and secondary metering circuit 126. PPR 128, due to its connection to downstream pressures P-Pn, SM1-Pn, SM2-Pn, thus adds the highest one of the these downstream pressures to this regulated pressure valve to ultimately provide the inlet side pressure value of PPR 128. As stated above, the regulated pressure value of 0.2 MPa (30 psi is for exemplary purposes only, and other values are entirely contemplated.

    [0036] This inlet side pressure PM-P1 of PPR 128 is effectively equal to P2 sensed by BPR 120 assuming known losses through PSV 106, and is also effectively equal to SM1-P1 and SM2-P1 given the parallel configuration of metering circuits 122, 124, 126. BPR 120 is operable to increase P1 as fuel is bypassed therethrough to the inlet side of pump 112 based upon this sensed value of P2. As an example, when PPR 128 reflects a downstream pressure change in one of secondary metering circuits 124, 126 as pressure value PM-P1, BPR 120 detects this pressure value, and increases its own restriction to increase PI as flow is bypassed back to pump 112 to increase pressure P1 to maintain a nearly constant pressure differential across FMV 116. BPR 120 may be a proportional, integral, or proportional plus integral control device to achieve the aforementioned functionality. The amount of metered flow then provided to parallel metering circuit 108 by FMV 116 is adjusted via adjusting the port area of FMV 116 to ensure enough flow is provided to maintain the desired minimum operational pressure drop across each of secondary metering circuits 124, 126.

    [0037] FIG. 2 illustrates the flexibility of the above described system 100 inasmuch as parallel metering system 108 may include additional secondary metering circuits, e.g. third secondary metering circuit 130. As can be seen in FIG. 2, PPR 128 also senses the downstream pressure SM3-Pn of third secondary metering circuit 130, and correspondingly sets PM-P1 to an appropriate value based upon the sensed pressure values P-Pn, SM1-Pn, SM2-Pn, SM3-Pn as described above. Those skilled in the art will recognize that system 100 may employ a greater number of secondary metering circuits based upon combustor needs, and the configurations shown herein are for exemplary purposes only.

    [0038] Turning now to FIG. 3, an alternative embodiment of system 100 is illustrated. This embodiment is similar to the embodiment shown at FIGS. 1 and 2, except that it incorporates a supply arrangement 102 which includes a boost pump 110 and two positive displacement pumps 112a, 112b and a pump switching system 134 for switching between and/or combining the output flows of the pumps 112a, 112b such as that disclosed in U.S. Pat. App. Nos. 12/683,685 and published as US 2001/0162724. BPR 120 is in operable communication with pump switching system 134 govern the particular flow settings provided by pump switching system 134 to ensure an adequate pressure value P1 is provided to maintain the nearly constant pressure differential across FMV 116. Beyond the foregoing distinction, the embodiment shown in FIG. 3 is functionally the same as that described at FIGS. 1 and 2 above.

    [0039] Turning now to FIG. 4, shows another embodiment of system 100 that, instead of utilizing secondary metering circuits 124, 126 with proportional throttling control via THV's 140 alone, utilizes secondary metering circuits 124, 126 with integrated throttling. In this configuration, instead of positioning THV's 140 directly based on the sensed FMV 136 differential pressure ((SM1-P1) - (SM1-P2) and (SM2-P1) - (SM2-P2)), FMV 136 differential pressure is sensed across head regulator 142. Based on the sensed pressure, head regulator 142 is positioned to regulate the additional supply (Psf) and drain (Pb) pressures to regulate THV 140 control pressure P4-1 and P4-2 to control the position of THV 140 and therefore the restriction created thereby. The combination of the head regulator 142 and THV 140 act to regulate the FMV 136 differential pressure to a nearly constant value. It will be recognized that the embodiment shown in FIG. 4 may include fewer or greater secondary metering circuits, and also incorporate a supply arrangement 102 that includes a dual pump configuration such as that described relative to FIG. 3.

    [0040] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

    [0041] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law.


    Claims

    1. An engine fuel system (100) comprising:

    a supply arrangement (102) including at least one pump (112) for providing an outlet flow of fuel;

    a bypass metering system (104) in fluid communication with the supply arrangement and supplied by the supply arrangement (102) with the outlet flow of fuel at pressure (P1), the bypass metering system (104) including

    a fuel metering valve (116) and

    a bypass regulator (120) in fluid communication with an inlet of the fuel metering valve and an inlet of the at least one pump, the bypass regulator is operably connected to detect a pressure of the metered flow of fuel from the fuel metering valve, the bypass regulator operable to bypass at least a portion of the outlet flow of fuel from the at least one pump back to the inlet of the at least one pump;

    a parallel metering system (108) for providing fuel to multiple combustor locations via multiple metered flow paths arranged in parallel, the parallel metering system (108) including

    a primary regulated circuit (122) and

    at least two secondary metering circuits (124, 126) arranged in parallel with the primary regulated circuit (122), the parallel metering system in fluid communication with the bypass metering system such that it receives a metered flow of fuel from the fuel metering valve (116) of the bypass metering system, wherein each of the secondary metering circuits includes a secondary metering circuit fuel metering valve (136) and a throttling valve (140) operably connected to an inlet and an outlet of the fuel metering valve to maintain a substantially constant pressure differential across the fuel metering valve; and

    wherein the primary regulated circuit includes a parallel pressure regulator (128) that is operably connected to the primary regulated circuit and the at least two secondary metering circuits to detect a pressure (P-Pn, SMI-Pn, SM2-Pn) in each of the primary regulated circuit and at least two secondary metering circuits, wherein the parallel pressure regulator is operably connected to the at least two secondary metering circuits downstream from the throttling valve.


     
    2. The engine fuel system of claim 1, wherein the at least one pump of the supply arrangement is a positive displacement pump.
     
    3. The engine fuel system of claim 1, wherein the at least one pump of the supply arrangement includes two pumps (112a, 112b) in parallel with one another.
     
    4. The engine fuel system of claim 3, further comprising a pump switching system operably connected to each of the two pumps, the pump switching system operable to combine or switch between outlet flows from each of the two pumps to provide the outlet flow of the supply arrangement, and optionally wherein the two pumps are positive displacement pumps.
     
    5. The engine fuel system of claim 1, wherein the bypass regulator is operably connected to an outlet of the fuel metering valve of the bypass metering system to detect the pressure of the metered flow of fuel from the fuel metering valve.
     
    6. The engine fuel system of claim 1, wherein the at least two secondary metering circuits include the fuel metering valve and a head regulator (142) operably connected to an inlet and an outlet of the fuel metering valve, and further comprise the throttling valve connected to the outlet of the fuel metering valve and the head regulator to maintain a substantially constant pressure differential across the fuel metering valve.
     
    7. The engine fuel system of claim 1, further comprising a pressurizing and shutoff valve (106) arranged such that the metered flow of fuel from fuel metering valve is directed through the pressurizing and shutoff valve prior to being received by the parallel metering system.
     
    8. The engine fuel system of any one of claims 1 to 4 or 7, wherein:

    the bypass metering system is operably connected to an outlet of the fuel metering valve to detect a pressure at the outlet of the fuel metering valve, the bypass regulator operable to maintain a substantially constant pressure differential across the fuel metering valve; and

    the parallel pressure regulator is operable to set an inlet side pressure of the parallel pressure regulator at least as high as a highest one of the detected pressures of the primary and at least two secondary metering circuits, plus a regulated pressure value of the parallel pressure regulator.


     
    9. The engine fuel system of claim 8, wherein the fuel metering valve is operable to adjust the metered flow of fuel in response to a change in the inlet side pressure of the parallel pressure regulator.
     
    10. A method for managing flow of fuel in an engine fuel system (100) having a parallel metering system (108) for providing fuel to multiple combustor locations via multiple metered flow paths arranged in parallel, the parallel metering system including a primary regulated circuit (122) and at least two secondary metering circuits (124, 126), the method comprising the steps of:

    providing a metered flow of fuel to the parallel metering circuit, the metered flow of fuel divided between the primary regulated circuit (122) and at least two secondary metering circuits (124, 126), wherein each of the secondary metering circuits includes a throttling valve (140) and a fuel metering valve (136) regulated by said throttling valve;

    detecting, with a parallel pressure regulator (128) of the primary regulated circuit, a downstream pressure (P-Pn) of the primary regulated circuit and downstream pressures (SM1-Pn, SM2-Pn) of each of the at least two secondary metering circuits;

    adjusting an inlet side pressure of the parallel pressure regulator to be at least as high as a highest one of the detected downstream pressures of the primary regulated circuit and the at least two secondary metering circuits, plus a regulated pressure value of the parallel pressure regulator;

    detecting, with a bypass regulator (120) of a bypass metering system (104) in fluid communication with the parallel metering system (108), the adjusted inlet side pressure of the parallel pressure regulator; and

    adjusting an inlet pressure of a flow of fuel to a fuel metering valve (116) of the bypass metering system using the bypass regulator to maintain a substantially constant pressure differential across the fuel metering valve by controlling a flow of the fuel that is bypassed back to a low pressure side of a pump (112).


     
    11. The method of claim 10, further comprising the step of adjusting an outlet flow of fuel from the fuel metering valve in response to the adjusted inlet side pressure of the parallel pressure regulator.
     
    12. The method of claim 11, further comprising the step of bypassing a portion of an outlet flow of fuel from a positive displacement pump back to an inlet of the positive displacement pump.
     


    Ansprüche

    1. Kraftstoffanlage (100) für einen Motor, umfassend:

    eine Versorgungsanordnung (102), die wenigstens eine Pumpe (112) zum Bereitstellen eines Auslassflusses von Kraftstoff umfasst,

    ein Bypassmesssystem (104), das in fluidischer Verbindung mit der Versorgungsanordnung steht und von der Versorgungsanordnung (102) mit dem Auslassfluss von Kraftstoff bei einem Druck (P1) versorgt wird, wobei das Bypassmesssystem (104) Folgendes umfasst:

    ein Kraftstoffmessventil (116) und

    einen Bypassregler (120), der in fluidischer Verbindung mit einem Einlass des Kraftstoffmessventils und einem Einlass der wenigstens einen Pumpe steht, wobei der Bypassregler wirkverbunden ist, um einen Druck des von dem Kraftstoffmessventil kommenden, gemessenen Flusses von Kraftstoff zu erkennen, wobei der Bypassregler in der Lage ist, wenigstens einen Teil des von der wenigstens einen Pumpe kommenden Auslassflusses von Kraftstoff zurück zu dem Einlass der wenigstens einen Pumpe umzuleiten,

    ein paralleles Messsystem (108), um mehrere Brennkammerstellen über mehrere parallel angeordnete Pfade für den gemessenen Fluss mit Kraftstoff zu versorgen, wobei das parallele Messsystem (108) Folgendes umfasst:

    einen primären Regelkreis (122) und

    wenigstens zwei sekundäre Messkreise (124, 126), die parallel zu dem primären Regelkreis (122) angeordnet sind, wobei das parallele Messsystem auf eine solche Weise mit dem Bypassmesssystem in fluidischer Verbindung steht, dass es einen gemessenen Fluss von Kraftstoff von dem Kraftstoffmessventil (116) des Bypassmesssystems aufnimmt, wobei jeder der sekundären Messkreise ein Kraftstoffmessventil (136) in dem sekundären Messkreis und ein Drosselventil (140) umfasst, das mit einem Einlass und einem Auslass des Kraftstoffmessventils wirkverbunden ist, um eine im Wesentlichen konstante Druckdifferenz über das Kraftstoffmessventil aufrechtzuerhalten, und

    wobei der primäre Regelkreis einen parallelen Druckregler (128) umfasst, der mit dem primären Regelkreis und den wenigstens zwei sekundären Messkreisen wirkverbunden ist, um einen Druck (P-Pn, SM1-Pn, SM2-Pn) in jeweils dem primären Regelkreis und den wenigstens zwei sekundären Messkreisen zu erkennen, wobei der parallele Druckregler stromabwärts von dem Drosselventil mit den wenigstens zwei sekundären Messkreisen wirkverbunden ist.


     
    2. Kraftstoffanlage für einen Motor nach Anspruch 1, wobei die wenigstens eine Pumpe der Versorgungsanordnung eine Verdrängerpumpe ist.
     
    3. Kraftstoffanlage für einen Motor nach Anspruch 1, wobei die wenigstens eine Pumpe der Versorgungsanordnung zwei parallel zueinander geschaltete Pumpen (112a, 112b) umfasst.
     
    4. Kraftstoffanlage für einen Motor nach Anspruch 3, ferner umfassend ein Pumpenumschaltsystem, das mit jeder der zwei Pumpen wirkverbunden ist, wobei das Pumpenumschaltsystem in der Lage ist, zwischen Auslassflüssen von jeder der zwei Pumpen umzuschalten oder dieselben zu vereinen, um den Auslassfluss der Versorgungsanordnung bereitzustellen, und wobei optional die zwei Pumpen Verdrängerpumpen sind.
     
    5. Kraftstoffanlage für einen Motor nach Anspruch 1, wobei der Bypassregler mit einem Auslass des Kraftstoffmessventils des Bypassmesssystems wirkverbunden ist, um den Druck des von dem Kraftstoffmessventil kommenden, gemessenen Flusses von Kraftstoff zu erkennen.
     
    6. Kraftstoffanlage für einen Motor nach Anspruch 1, wobei die wenigstens zwei sekundären Messkreise das Kraftstoffmessventil und einen Gefälleregler (142) umfassen, der mit einem Einlass und einem Auslass des Kraftstoffmessventils wirkverbunden ist, und ferner das mit dem Auslass des Kraftstoffmessventils und dem Gefälleregler verbundene Drosselventil umfassen, um eine im Wesentlichen konstante Druckdifferenz über das Kraftstoffmessventil aufrechtzuerhalten.
     
    7. Kraftstoffanlage für einen Motor nach Anspruch 1, ferner umfassend ein Druckbeaufschlagungs- und Absperrventil (106), das auf eine solche Weise angeordnet ist, dass der von dem Kraftstoffmessventil kommende, gemessene Fluss von Kraftstoff durch das Druckbeaufschlagungs- und Absperrventil geleitet wird, bevor er von dem parallelen Messsystem aufgenommen wird.
     
    8. Kraftstoffanlage für einen Motor nach einem der Ansprüche 1 bis 4 oder 7, wobei:

    das Bypassmesssystem mit einem Auslass des Kraftstoffmessventils wirkverbunden ist, um einen Druck an dem Auslass des Kraftstoffmessventils zu erkennen, wobei der Bypassregler in der Lage ist, eine im Wesentlichen konstante Druckdifferenz über das Kraftstoffmessventil aufrechtzuerhalten, und

    der parallele Druckregler in der Lage ist, einen einlassseitigen Druck des parallelen Druckreglers wenigstens so hoch wie den höchsten der erkannten Drücke des primären und der wenigstens zwei sekundären Messkreise plus einem Wert des geregelten Drucks des parallelen Druckreglers zu setzen.


     
    9. Kraftstoffanlage für einen Motor nach Anspruch 8, wobei das Kraftstoffmessventil in der Lage ist, in Reaktion auf eine Veränderung des einlassseitigen Drucks des parallelen Druckreglers den gemessenen Fluss von Kraftstoff einzustellen.
     
    10. Verfahren zum Handhaben eines Flusses von Kraftstoff in einer Kraftstoffanlage (100) für einen Motor, die ein paralleles Messsystem (108) aufweist, um mehrere Brennkammerstellen über mehrere parallel angeordnete Pfade für den gemessenen Fluss mit Kraftstoff zu versorgen, wobei das parallele Messsystem einen primären Regelkreis (122) und wenigstens zwei sekundäre Messkreise (124, 126) umfasst, wobei das Verfahren die folgenden Schritte umfasst:

    Versorgen des parallelen Messkreises mit einem gemessenen Fluss von Kraftstoff, wobei der gemessene Fluss von Kraftstoff zwischen dem primären Regelkreis (122) und den wenigstens zwei sekundären Messkreisen (124, 126) aufgeteilt ist, wobei jeder der sekundären Messkreise ein Drosselventil (140) und ein Kraftstoffmessventil (136) umfasst, das durch das Drosselventil geregelt wird,

    mit einem parallelen Druckregler (128) des primären Regelkreises Erkennen eines stromabwärts herrschenden Drucks (P-Pn) des primären Regelkreises und von stromabwärts herrschenden Drücken (SM1-Pn, SM2-Pn) jedes der wenigstens zwei sekundären Messkreise,

    Einstellen eines einlassseitigen Drucks des parallelen Druckreglers so, dass dieser wenigstens so hoch wie der höchste der erkannten stromabwärts herrschenden Drücke des primären Regelkreises und der wenigstens zwei sekundären Messkreise plus einem Wert des geregelten Drucks des parallelen Druckreglers ist,

    mit einem Bypassregler (120) eines Bypassmesssystems (104), das in fluidischer Verbindung mit dem parallelen Messsystem (108) steht, Erkennen des eingestellten einlassseitigen Drucks des parallelen Druckreglers, und

    Einstellen eines Einlassdrucks eines Flusses von Kraftstoff zu einem Kraftstoffmessventil (116) des Bypassmesssystems mit Hilfe des Bypassreglers, um eine im Wesentlichen konstante Druckdifferenz über das Kraftstoffmessventil durch Steuern eines Flusses des Kraftstoffs, der zurück zu einer Niederdruckseite einer Pumpe (112) umgeleitet wird, aufrechtzuerhalten.


     
    11. Verfahren nach Anspruch 10, ferner umfassend den Schritt des Einstellens eines von dem Kraftstoffmessventil kommenden Auslassflusses von Kraftstoff in Reaktion auf den eingestellten einlassseitigen Druck des parallelen Druckreglers.
     
    12. Verfahren nach Anspruch 11, ferner umfassend den Schritt des Umleitens eines Teils eines von einer Verdrängerpumpe kommenden Auslassflusses von Kraftstoff zurück zu einem Einlass der Verdrängerpumpe.
     


    Revendications

    1. Système de combustible de moteur (100) comprenant :

    un agencement d'alimentation (102) comportant au moins une pompe (112) pour fournir un flux de sortie de combustible ;

    un système de dosage de dérivation (104) en communication fluidique avec l'agencement d'alimentation et alimenté, par l'agencement d'alimentation (102), en flux de sortie de combustible à une pression (P1), le système de dosage de dérivation (104) comportant

    une soupape de dosage de combustible (116) et

    un régulateur de dérivation (120) en communication fluidique avec une entrée de la soupape de dosage de combustible et une entrée de l'au moins une pompe, le régulateur de dérivation étant connecté fonctionnellement pour détecter une pression du flux dosé de combustible provenant de la soupape de dosage de combustible, le régulateur de dérivation permettant de mettre en dérivation au moins une partie du flux de sortie de combustible provenant de l'au moins une pompe en retour à l'entrée de l'au moins une pompe ;

    un système de dosage parallèle (108) pour fournir du combustible à de multiples emplacements de chambre de combustion via de multiples voies d'écoulement dosées agencées en parallèle, le système de dosage parallèle (108) comportant

    un circuit régulé primaire (122) et

    au moins deux circuits de dosage secondaires (124, 126) agencés en parallèle avec le circuit régulé primaire (122), le système de dosage parallèle étant en communication fluidique avec le système de dosage de dérivation de telle sorte qu'il reçoit un flux dosé de combustible provenant de la soupape de dosage de combustible (116) du système de dosage de dérivation, dans lequel chacun des circuits de dosage secondaires comporte une soupape de dosage de combustible (136) de circuit de dosage secondaire et une soupape d'étranglement (140) connectée fonctionnellement à une entrée et à une sortie de la soupape de dosage de combustible pour maintenir une pression différentielle sensiblement constante à travers la soupape de dosage de combustible ; et

    dans lequel le circuit régulé primaire comporte un régulateur de pression parallèle (128) qui est connecté fonctionnellement au circuit régulé primaire et auxdits au moins deux circuits de dosage secondaires pour détecter une pression (P-Pn, SM1-Pn, SM2-Pn) dans chaque circuit parmi le circuit régulé primaire et au moins deux circuits de dosage secondaires, dans lequel le régulateur de pression parallèle est connecté fonctionnellement auxdits au moins deux circuits de dosage secondaires en aval de la soupape d'étranglement.


     
    2. Système de combustible de moteur selon la revendication 1, dans lequel l'au moins une pompe de l'agencement d'alimentation est une pompe volumétrique.
     
    3. Système de combustible de moteur selon la revendication 1, dans lequel l'au moins une pompe de l'agencement d'alimentation comporte deux pompes (112a, 112b) en parallèle l'une avec l'autre.
     
    4. Système de combustible de moteur selon la revendication 3, comprenant en outre un système de commutation de pompe connecté fonctionnellement à chacune des deux pompes, le système de commutation de pompe permettant de combiner ou de commuter entre des flux de sortie provenant de chacune des deux pompes pour fournir le flux de sortie de l'agencement d'alimentation, et éventuellement dans lequel les deux pompes sont des pompes volumétriques.
     
    5. Système de combustible de moteur selon la revendication 1, dans lequel le régulateur de dérivation est connecté fonctionnellement à une sortie de la soupape de dosage de combustible du système de dosage de dérivation pour détecter la pression du flux dosé de combustible provenant de la soupape de dosage de combustible.
     
    6. Système de combustible de moteur selon la revendication 1, dans lequel lesdits aux moins deux circuits de dosage secondaires comportent la soupape de dosage de combustible et un régulateur de tête (142) connecté fonctionnellement à une entrée et une sortie de la soupape de dosage de combustible, et comprennent en outre la soupape d'étranglement connectée à la sortie de la soupape de dosage de combustible et au régulateur de tête pour maintenir une pression différentielle sensiblement constante à travers la soupape de dosage de combustible.
     
    7. Système de combustible de moteur selon la revendication 1, comprenant en outre une soupape de mise sous pression et d'arrêt (106) agencée de telle sorte que le flux dosé de combustible provenant de la soupape de dosage de combustible est dirigé à travers la soupape de mise sous pression et d'arrêt avant d'être reçu par le système de dosage parallèle.
     
    8. Système de combustible de moteur selon l'une quelconque des revendications 1 à 4 ou 7, dans lequel :

    le système de dosage de dérivation est connecté fonctionnellement à une sortie de la soupape de dosage de combustible pour détecter une pression à la sortie de la soupape de dosage de combustible, le régulateur de dérivation permettant de maintenir une pression différentielle sensiblement constante à travers la soupape de dosage de combustible ; et

    le régulateur de pression parallèle permet de régler une pression de côté d'entrée du régulateur de pression parallèle de manière à ce qu'elle soit au moins aussi élevée qu'une pression la plus élevée parmi les pressions détectées du circuit primaire et desdits au moins deux circuits de dosage secondaires, plus une valeur de pression régulée du régulateur de pression parallèle.


     
    9. Système de combustible de moteur selon la revendication 8, dans lequel la soupape de dosage de combustible permet de régler le flux dosé de combustible en réponse à un changement de pression de côté d'entrée du régulateur de pression parallèle.
     
    10. Procédé de gestion d'un flux de combustible dans un système de combustible de moteur (100) comportant un système de dosage parallèle (108) pour fournir du combustible à de multiples emplacements de chambre de combustion via de multiples voies d'écoulement dosées agencées en parallèle, le système de dosage parallèle comportant un circuit régulé primaire (122) et au moins deux circuits de dosage secondaires (124, 126), le procédé comprenant les étapes de :

    fourniture d'un flux dosé de combustible au circuit de dosage parallèle, le flux dosé de combustible étant divisé entre le circuit régulé primaire (122) et au moins deux circuits de dosage secondaires (124, 126), dans lequel chacun des circuits de dosage secondaires comporte une soupape d'étranglement (140) et une soupape de dosage de combustible (136) régulée par ladite soupape d'étranglement ;

    détection, avec un régulateur de pression parallèle (128) du circuit régulé primaire, d'une pression aval (P-Pn) du circuit régulé primaire et de pressions aval (SM1-Pn, SM2-Pn) de chacun desdits au moins deux circuits de dosage secondaires ;

    réglage d'une pression de côté d'entrée du régulateur de pression parallèle de manière à ce qu'elle soit au moins aussi élevée qu'une pression la plus élevée parmi les pressions aval détectées du circuit régulé primaire et desdits au moins deux circuits de dosage secondaires, plus une valeur de pression régulée du régulateur de pression parallèle ;

    détection, avec un régulateur de dérivation (120) d'un système de dosage de dérivation (104) en communication fluidique avec le système de dosage parallèle (108), de la pression de côté d'entrée réglée du régulateur de pression parallèle ; et réglage d'une pression d'entrée d'un flux de combustible vers une soupape de dosage de combustible (116) du système de dosage de dérivation à l'aide du régulateur de dérivation pour maintenir une pression différentielle sensiblement constante à travers la soupape de dosage de combustible par régulation d'un flux du combustible qui est mis en dérivation en retour à un côté basse pression d'une pompe (112).


     
    11. Procédé selon la revendication 10, comprenant en outre l'étape de réglage d'un flux de sortie de combustible provenant de la soupape de dosage de combustible en réponse à la pression de côté d'entrée réglée du régulateur de pression parallèle.
     
    12. Procédé selon la revendication 11, comprenant en outre l'étape de dérivation d'une partie d'un flux de sortie de combustible provenant d'une pompe volumétrique en retour à une entrée de la pompe volumétrique.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description