Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
  • F02C7/22—Fuel supply systems
  • F02C7/228—Dividing fuel between various burners
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
  • F23K5/00—Feeding or distributing other fuel to combustion apparatus
  • F23K5/02—Liquid fuel
  • F23K5/06—Liquid fuel from a central source to a plurality of burners
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C9/00—Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants
  • F02C9/26—Control of fuel supply
  • F02C9/32—Control of fuel supply characterised by throttling of fuel
  • F02C9/34—Joint control of separate flows to main and auxiliary burners
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
  • F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
  • F23R3/28—Continuous combustion chambers using liquid or gaseous fuel characterised by the fuel supply
  • F23R3/34—Feeding into different combustion zones
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
  • F23D2900/00016—Preventing or reducing deposit build-up on burner parts, e.g. from carbon
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
  • F23R2900/00—Special features of, or arrangements for continuous combustion chambers; Combustion processes therefor
  • F23R2900/00004—Preventing formation of deposits on surfaces of gas turbine components, e.g. coke deposits

Definitions

• the present invention relates to the injection of fuel into the combustion chamber of an engine, in particular an aircraft engine.
• It relates more particularly to the fuel supply of injectors in a combustion chamber with low emission of NOx nitrogen oxides.
• the fuel is injected into the combustion chamber of the engine via two injection circuits.
• a circuit called pilot circuit has an optimized continuous flow for low speeds.
• a circuit called the main circuit has an intermittent flow optimized for high speeds. It completes the fuel flow to allow in particular to achieve the power required for takeoff.
• the main circuit is used non-permanently, when there is a need for additional engine thrust, and its flow may be zero or very low at certain speeds.
• the intermittent operation of the main circuit coupled with the high temperatures in the engine has the effect of inducing undesirable decomposition or coking of the stagnant fuel in the main circuit, when the fuel flow therein is greatly reduced or cut off.
• the power system which comprises a control device which controls a fuel metering device and a fuel distribution valve between the two circuits, then opens the distribution valve to the position controlled by the regulation corresponding to a regime. wish. Part of the fuel flow is then used to fill the main circuit and is not injected into the combustion chamber at this time.
• the invention aims to solve the problems of the prior art by providing a fuel injection system in a combustion chamber of an engine, comprising at least two fuel circuits, one with a constant flow rate and the other with intermittent flow, metering elements and distribution of fuel between the two circuits and a means of control of these bodies, the intermittent flow circuit being capable of being purged,
• control means upon receipt of a fuel filling order of the circuits following a purge of the intermittent flow circuit, the control means is adapted to
• the fuel flow injected into the combustion chamber remains in accordance with the expected flow rate for proper operation, in particular there is no underdosing of fuel due to the filling of the intermittent flow circuit. There is no response delay of the intermittent flow circuit or desired revving at the end of filling of the intermittent flow circuit.
• the metering and fuel distribution units comprise a fuel metering device and a fuel distribution valve, the metering device for adjusting the fuel flow rate supplied to the intermittent flow circuits and to the fuel distribution valve. flow rate, and the distribution valve for distributing the fuel between the intermittent flow circuit and the permanent flow circuit.
• the metering unit and the distribution valve are connected in series between a fuel pump and the injection circuits.
• the metering and fuel distribution components comprise a fuel metering device for the permanent flow circuit and a fuel metering device for the intermittent flow circuit.
• the two feeders are then connected in parallel between the fuel pump and the injection circuits and ensure both the fuel dosage for each of the circuits and the distribution of fuel between the two circuits.
• the fuel injection system is further characterized in that, on receipt of a fuel filling setpoint of the circuits following a purging of the intermittent flow circuit, the control means is adapted at
• the invention provides a robust solution so that the fueling duration of the intermittent flow circuit does not affect the acceleration of the engine.
• the invention makes it possible to anticipate the need for using the intermittent flow circuit while avoiding filling it with fuel when it is not necessary.
• the intermittent flow circuit remains in the purged state for as long as possible, which eliminates the risk of coking the stagnant fuel.
• control means is adapted to determine, for a given point of the flight range, the set point as a function of the thrust threshold of the engine.
• control means is adapted to determine the thrust threshold of the engine as the thrust point from which the intermittent flow circuit is used.
• control means is adapted to determine the setpoint value as a function of the position of the throttle control lever actuated by a user.
• the invention also relates to a fuel injection method in a combustion chamber of an engine, by an injection system comprising at least two fuel circuits, one with a constant flow rate and the other with an intermittent flow rate, fuel proportioning and distributing means between the two circuits and means for controlling these members, the intermittent flow circuit being capable of being purged, characterized in that, on receipt of a fuel filling order, circuits following a purge of the intermittent flow circuit, it comprises the step of:
• control of the dosing and distribution members to obtain a predetermined fuel flow rate greater than the flow rate corresponding to the filling order and to supply the resulting excess fuel to the intermittent flow circuit for a predetermined duration.
• the fuel injection method is characterized in that, on receiving a fuel filling instruction from the circuits following a purge of the intermittent flow circuit, it comprises the steps of: - comparison of the received setpoint value with a set point, and if the value of the setpoint is higher than the set point,
• the steps of the method according to the invention are implemented by computer program instructions.
• the invention also relates to a computer program on an information medium, this program being capable of being implemented in a computer, this program comprising instructions adapted to the implementation of the steps of a process as described above.
• This program can use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other form desirable shape.
• the invention also relates to a computer readable information medium, and comprising computer program instructions suitable for implementing the steps of a method as described above.
• the information carrier may be any entity or device capable of storing the program.
• the medium may comprise storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or a magnetic recording means, for example a diskette or a hard disk.
• the information medium can be a transmissible medium such as an electrical or optical signal, which can be routed via a cable electrical or optical, radio or other means.
• the program according to the invention can be downloaded in particular on an Internet type network.
• the information carrier may be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the method according to the invention.
• FIG. 1 schematically represents a fuel injection system in a combustion chamber of an engine, according to a first embodiment of the invention
• FIG. 2 schematically represents a fuel injection system in a combustion chamber of an engine, according to a second embodiment of the invention
• FIG. 3 represents a method of injecting fuel into a combustion chamber of an engine, according to one embodiment of the invention
• FIGS. 4a to 4f show fuel flow rates at various points of the system and a fuel distribution between the injection circuits, according to the present invention
• FIG. 5 represents another method of injecting fuel into a combustion chamber of an engine, according to an alternative embodiment of the invention.
• FIG. 6 represents an example of fuel flow, in connection with the process of FIG. 5, according to the present invention.
• FIG. 7 represents an example of setpoint and engine speed, in connection with the method of FIG. 5, according to the present invention.
• the invention is applied to a fuel injection system in a combustion chamber of an engine.
• a fuel injection system in a combustion chamber of an engine.
• the injection system comprises two fuel injection circuits in the combustion chamber, not shown.
• the first fuel injection circuit 1, said pilot circuit or idle circuit, has a limited and permanent flow. It comprises a set of injection nozzles symbolized by arrows.
• the second fuel injection circuit 2 is designed to supplement the fuel flow to the full gas point.
• I l allows to achieve all the power necessary for takeoff.
• This circuit also has a set of injection nozzles symbolized by arrows but it is not used permanently, its flow is therefore intermittent and can be zero or very low at certain speeds.
• An electronic control device 3 said FADEC, according to the English "Full Authority Digital Engine Control", controls a fuel metering member 4 which determines the fuel flow rate supplied to the two injection circuits 1 and 2.
• the regulating device 3 also controls a fuel distribution member 5 between the two injection circuits 1 and 2.
• the metering member 4 is a metering device that imposes the fuel flow that is supplied to all of the two injection circuits.
• the distribution member 5 is a distribution valve which distributes the fuel between the two injection circuits.
• the metering device 4 and the valve 5 are connected in series between a not shown fuel pump and the two injection circuits 1 and 2. The fuel metering is therefore first determined globally for the two circuits and then the distribution. fuel between the two circuits is made.
• Figure 2 shows a second embodiment of a fuel injection system. This second mode differs from the first by its dosing and fuel distribution components.
• the injection system comprises two fuel injection circuits 1 and 2 similar to those previously described. It also comprises a regulating device 3 similar to that previously presented. It comprises bodies 6 and 7 for dosing and distribution of fuel between the two circuits 1 and 2.
• the metering member and the distribution member are two metering units 6 and 7 controlled by the control device 3.
• each metering device 6, 7 imposes the fuel flow rate supplied to its respective injection circuit 1, 2 and the ratio of the fuel flow rates supplied to the injection circuits determines the distribution between the injection circuits.
• Each metering unit is thus a metering and fuel distribution member.
• the main circuit 2 is purged. This purge is controlled by the electronic control device 3 and can be performed in various ways.
• the two embodiments of fuel injection system may comprise more than two injection circuits. In all cases, at least one fuel injection circuit can be purged.
• FIG. 3 represents a method of injecting fuel into a combustion chamber of an engine, implemented in the first embodiment device described above, more particularly in the electronic control device 3.
• the method comprises steps E1 to E3.
• Step E1 is the reception of a fuel filling order of the injection circuits, following a purging of the intermittent flow circuit 2. It is assumed that the filling order occurs at a time T1.
• FIG. 4a represents an example of total fuel flow D1 delivered to the combustion chamber by the injection circuits, as a function of time, corresponding to the filling order received.
• the total fuel flow delivered into the combustion chamber is equal to a first relatively low value DU up to time T1, then increases to a second value D12 higher than the first, between times T1 and T3. .
• the rate D1 then remains equal to the second value D12.
• the value DU is 750 kg / h
• the value D12 is 3000 kg / h
• the duration T3-T1 is 7 seconds.
• step E2 is the control of the dosing and distribution members 4 and 5 to obtain at the outlet of the metering member 4 a predetermined fuel flow D2 which is greater than the flow D1 corresponding to the filling order during a period of time. predetermined duration, and supplying the resulting excess fuel to the intermittent flow circuit 2 for the predetermined duration.
• This excess fuel corresponding to the difference of the flow rates D2-D1, serves to fill the main circuit 2.
• FIG. 4b represents the flow rate of fuel D2 delivered by the metering device 4 as a function of time.
• the fuel flow D2 delivered by the metering device is greater than the total fuel flow D1 delivered into the combustion chamber by the injection circuits, represented in FIG. 4a.
• the fuel flow D2 reaches a maximum value D21 greater than the value of the flow D1.
• the instant T1 is the moment when the filling order occurs, as previously explained, and the instant T2 is the moment when the main circuit 2 is filled with fuel.
• the instant T2 is earlier than the instant T3.
• the duration T2-T1 is 4 seconds and the flow rate value D21 is 4500 kg / h.
• Figure 4c shows the fuel distribution assigned to the main circuit 2, as a function of time. This distribution is determined by the distribution valve 5 and is represented as a percentage.
• the duration (T2-T1), the flow rate value D2 between the instants T1 and T2 as well as the distribution between the two fuel injection circuits between these two instants are predetermined. These quantities depend on the constitution of the main circuit 2, in particular the volume to be filled with fuel.
• the main circuit 2 is therefore filled with fuel thanks to the combination of the surplus fuel flow at the outlet of the metering device 4 and the simultaneous distribution made by the distribution valve 5 which sends the excess fuel to the main circuit 2.
• the flow fuel that allows the filling of the main circuit is the difference between the flow D2 delivered by the metering device and the flow Dl delivered in the combustion chamber.
• FIG. 4d represents the fuel filling curve of the main circuit 2, expressed as a percentage of the volume of the main circuit, as a function of time.
• step E3 is the return to a conventional control mode in which the flow rate of fuel D2 at the metering outlet 4 is equal to the flow rate of fuel D1 delivered to the combustion chamber, and in which the distribution valve 5 is set so that the flow D3 delivered by the main circuit 2 increases gradually.
• FIG. 4e represents the flow D3 delivered by the main circuit 2, as a function of time
• FIG. 4f represents the flow D4 delivered by the pilot circuit 1 as a function of time.
• the flow D4 in the pilot circuit is equal to the total flow Dl between instants T1 and T2, then it remains at a plateau value to finally fall back to a low value.
• the flow D3 is zero until the moment T2 then increases.
• the rate D1 is equal to the sum of the flow rates D3 and D4.
• the two fuel injection circuits are fed in parallel.
• the total fuel flow delivered into the combustion chamber is identical to the total flow Dl shown in Figure 4a.
• the fuel flow delivered by the pilot circuit 1 is identical to the flow rate D4 shown in FIG. 4f.
• the fuel flow rate supplied to the main circuit 2 is equal to the difference between the flow rate D2 (FIG. 4b) and the flow rate D1 (FIG. 4a), between the instants T1 and T2, and then equal to the flow rate D3 (FIG. from the moment T2.
• FIG. 5 represents another method of injecting fuel into a combustion chamber of an engine, implemented in the previously described system embodiment, more particularly in the electronic control device 3.
• the method comprises steps Eli at E14.
• Step Eli is the reception of a fuel filling instruction of the injection circuits, following a purge of the intermittent flow circuit 2. It is assumed that the filling instruction occurs at a time T11.
• the fuel filling instruction of the injection circuits corresponds to a thrust instruction of the engine which is determined by the position of the throttle actuated by a user.
• FIG. 6 represents an example of total fuel flow D (t) delivered in the combustion chamber by the injection circuits 1 and 2, as a function of time, corresponding to the filling setpoint received.
• the total fuel flow delivered into the combustion chamber is equal to a relatively low first value D1 until time T11 at which the fuel filling setpoint of the injection circuits is received, then increases to a second value D12 higher than the first, between times T11 and T14.
• the rate D (t) then remains equal to the second value D12.
• the value DU is 750 kg / h
• the value D12 is 3000 kg / h
• the duration T14-T11 is equal to 7 seconds.
• a threshold Garlic total fuel flow is determined.
• the threshold Garlic is the flow rate corresponding to a predetermined distribution of fuel between the permanent flow circuit and the intermittent flow circuit.
• the threshold flow rate corresponds to a thrust threshold of the engine.
• the flow rate threshold is the rate at which the intermittent flow circuit is used.
• the flow threshold For a fuel flow less than or equal to the flow threshold, that is to say for an engine thrust less than or equal to the thrust threshold of the engine, only the permanent flow circuit 1 is biased. From the flow threshold, that is to say the thrust threshold, the intermittent flow circuit 2 also starts to be solicited.
• the threshold flow rate is reached at a time T12.
• the thrust point corresponding to the air flow threshold is at an intermediate level between the ground idle thrust and the take-off thrust.
• the flow threshold and therefore the engine thrust threshold, is chosen to correspond to another predetermined distribution of fuel between the permanent flow circuit and the intermittent flow circuit. In all cases, this other distribution depends on the use of the intermittent flow circuit.
• the flow A12 is the maximum flow rate that can pass in the permanent flow circuit.
• the flow A12 is reached at a time T13 greater than T12.
• the duration (T13-T12) is for example 0.6 seconds.
• the intermittent flow circuit which has been previously purged, remains empty until time T12 when it begins to be solicited.
• the intermittent flow circuit must first be filled before fuel can be delivered to the combustion chamber.
• the filling of the intermittent flow circuit lasts a minimum time which is greater than the duration (T13-T12).
• the filling time of the intermittent flow circuit is 2 seconds.
• the intermittent flow circuit becomes functional only after refueling. There is therefore according to the prior art a period of time from time T13 during which the flow of fuel injected into the combustion chamber is capped at the value A12 reached at this time.
• Step E12 is the determination of a setpoint threshold B by the electronic control device 3.
• the set point is determined according to the engine thrust threshold, ie the flow threshold Air, corresponding to the predetermined fuel distribution between the permanent flow circuit. and the intermittent flow circuit. It is recalled that the threshold flow rate is preferably the flow rate from which the intermittent flow circuit is used.
• the setpoint is the setpoint value for reaching the thrust value equal to the thrust threshold.
• the setpoint threshold B changes according to the point of the flight envelope of the aircraft, that is why it is continuously calculated by the control device 3.
• Step E1 is followed by step E13 which is the comparison of the received setpoint value with the current set point B provided by step E12.
• the electronic control device 3 controls the metering device and the distribution valve in a conventional manner.
• step E13 is followed by step E14 which is the control of the dosing and distribution members 4, 5 to fill the intermittent flow circuit 2 beforehand. reaching the push-point threshold.
• the crossing of the thrust threshold of the engine that is to say the flow threshold Garlic, is anticipated.
• the intermittent flow circuit is therefore filled with fuel in advance of the moment of its actual use.
• the filling of the intermittent flow circuit starts at the instant T11, or alternatively at a time between the instants T11 and (T12-DR), where DR is the filling time of the intermittent flow circuit 2, so that the intermittent flow circuit is filled with fuel and ready to deliver fuel into the combustion chamber at time T12 where it is biased.
• FIG. 7 represents the engine speed and the applied setpoint corresponding to the example of FIG. 6, as a function of time.
• the engine speed is proportional to the thrust of the engine.
• the throttle is operated to apply a setpoint.
• the setpoint curve C (t) is equal to a first value Cil until time T11, then at this instant takes a second value C12.
• the value C12 is greater than the setpoint threshold B.
• the engine speed is equal to a first relatively low value R11 until the instant T11 at which the injection fuel filling instruction of the injection circuits is received, then it increases to a second value R12 higher than the first, between instants T11 and T14. The engine speed then remains equal to the second value R12.
• the value R11 is 2000 RPM
• the value R12 is 7000 RPM
• the duration T14-T11 is 7 seconds.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Fuel-Injection Apparatus (AREA)
• Supplying Secondary Fuel Or The Like To Fuel, Air Or Fuel-Air Mixtures (AREA)

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• 2014
  • 2014-08-20 BR BR112016003574-7A patent/BR112016003574B1/pt active IP Right Grant
  • 2014-08-20 WO PCT/FR2014/052105 patent/WO2015025109A1/fr not_active Ceased
  • 2014-08-20 EP EP14786970.5A patent/EP3036481B1/fr active Active
  • 2014-08-20 CA CA2921241A patent/CA2921241C/fr active Active
  • 2014-08-20 RU RU2016109978A patent/RU2669094C2/ru active
  • 2014-08-20 US US14/912,523 patent/US10072578B2/en active Active
  • 2014-08-20 CN CN201480049336.5A patent/CN105518387B/zh active Active

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