Ignition fuel supply method and device based on oil-gas ratio control

Abstract

The present application belongs to the field of engine control technology, and particularly relates to an ignition fuel supply method and device based on oil-gas ratio control, the method comprising: step S1, calculating an initially set fuel supply flow rate based on a given equivalent oil-gas ratio and a combustion chamber inlet pressure, and supplying fuel to the combustion chamber as a fuel supply set value; step S2, calculating an actual equivalent oil-gas ratio based on the actual fuel supply flow rate and the combustion chamber inlet pressure of the current cycle; step S3, when the actual equivalent oil-gas ratio is greater than the given equivalent oil-gas ratio, reducing the fuel supply set value at a set fuel supply change rate; conversely, increasing the fuel supply set value at a set fuel supply change rate; step S4, during the process of increasing the fuel supply set value, igniting the engine when the actual equivalent oil-gas ratio of the previous cycle is less than the given equivalent oil-gas ratio, and the actual equivalent oil-gas ratio of the current cycle is greater than or equal to the given equivalent oil-gas ratio. The present application improves the reliability of engine ignition.

Description

Technical Field

[0001] The present application belongs to the field of engine control technology, and in particular relates to an ignition fuel supply method and device based on oil-gas ratio control. Background Art

[0002] Currently, most aircraft engine initial fueling for ignition is performed using open-loop control (the absolute amount of initial fuel is determined based on atmospheric pressure or combustion chamber inlet pressure, and no further corrections are made based on engine status). This fails to account for issues such as excessive fueling due to initial overshoot of fueling accessories during engine ignition, or the inherent dispersion of the engine (the difference in gas volume during ignition). This can lead to problems such as ignition stall due to a rich fuel-to-gas ratio, or ignition failure due to a lean fuel-to-gas ratio. Some advanced electronically controlled engines utilize a "progressive" fueling method (where the initial fueling amount is set at a low value, and fuel is added at a constant rate until the appropriate fuel-to-gas ratio is achieved and ignition is successful). This method can address ignition failures caused by insufficient fueling of accessories, but it cannot address issues such as ignition stalls caused by initial overshoot of fueling accessories and the inherent dispersion of the engine. Summary of the Invention

[0003] In order to solve the above problems, the present application provides an ignition fuel supply method and device based on oil-gas ratio control to solve the ignition stall problem caused by overshoot of initial fuel supply to accessories.

[0004] In a first aspect, the present application provides an ignition fuel supply method based on oil-gas ratio control, which mainly includes:

[0005] Step S1: Calculating an initial fuel flow rate based on a given equivalent fuel-gas ratio and a combustion chamber inlet pressure, and supplying fuel to the combustion chamber as a given fuel supply value. The equivalent fuel-gas ratio refers to the ratio of the engine fuel flow rate to the combustion chamber inlet pressure.

[0006] Step S2: Calculate the actual equivalent fuel-gas ratio based on the actual fuel flow rate and the combustion chamber inlet pressure of the current cycle;

[0007] Step S3: when the actual equivalent oil-gas ratio is greater than the given equivalent oil-gas ratio, the fuel supply set value is reduced according to the set fuel supply change rate; conversely, when the actual equivalent oil-gas ratio is less than the given equivalent oil-gas ratio, the fuel supply set value is increased according to the set fuel supply change rate;

[0008] Step S4: During the process of increasing the fuel supply set value, when the actual equivalent fuel-gas ratio of the current cycle is less than the given equivalent fuel-gas ratio and the actual equivalent fuel-gas ratio of the current cycle is greater than or equal to the given equivalent fuel-gas ratio, ignite the engine.

[0009] Preferably, step S1 further includes:

[0010] Step S11: constructing a relationship between the equivalent fuel-gas ratio and the high-pressure converted speed, and determining the equivalent fuel-gas ratio boundary for each high-pressure converted speed that enables engine ignition;

[0011] Step S12: for each high-pressure converted speed, the middle value within the boundary range of the equivalent fuel-gas ratio is used as the given equivalent fuel-gas ratio;

[0012] Step S13: After the measured high-pressure speed meets the high-pressure speed limit of the oil supply condition, the high-pressure converted speed is calculated according to the measured high-pressure speed, and the given equivalent oil-gas ratio corresponding to the current high-pressure converted speed is determined.

[0013] Preferably, step S3 further comprises igniting the engine when the time for adjusting the fuel supply set value exceeds the forced ignition fuel supply time.

[0014] The second aspect of the present application provides an ignition fuel supply device based on oil-gas ratio control, which mainly includes:

[0015] A fuel supply setpoint initialization module is used to calculate an initial set fuel supply flow rate based on a given equivalent fuel-to-air ratio and a combustion chamber inlet pressure, and to supply fuel to the combustion chamber as the fuel supply setpoint value. The equivalent fuel-to-air ratio refers to the ratio of the engine fuel flow rate to the combustion chamber inlet pressure.

[0016] The actual equivalent fuel-gas ratio calculation module is used to calculate the actual equivalent fuel-gas ratio based on the actual fuel flow rate and combustion chamber inlet pressure of the current cycle;

[0017] a fuel supply set value adjustment module, configured to reduce the fuel supply set value at a set fuel supply change rate when the actual equivalent fuel-gas ratio is greater than the given equivalent fuel-gas ratio; and conversely, increase the fuel supply set value at a set fuel supply change rate when the actual equivalent fuel-gas ratio is less than the given equivalent fuel-gas ratio;

[0018] The engine ignition module is used to ignite the engine when the actual equivalent fuel-gas ratio of the previous cycle is less than the given equivalent fuel-gas ratio and the actual equivalent fuel-gas ratio of the current cycle is greater than or equal to the given equivalent fuel-gas ratio during the process of increasing the fuel supply set value.

[0019] Preferably, the fuel supply setpoint initial setting module includes:

[0020] An equivalent fuel-gas ratio construction unit is used to construct a relationship between the equivalent fuel-gas ratio and the high-pressure converted speed, and determine the equivalent fuel-gas ratio boundary that enables engine ignition corresponding to each high-pressure converted speed;

[0021] A given equivalent fuel-gas ratio construction unit is used to take, for each high-pressure converted speed, an intermediate value within the equivalent fuel-gas ratio boundary range as the given equivalent fuel-gas ratio;

[0022] The given equivalent oil-gas ratio determination unit is used to calculate the high-pressure conversion speed based on the measured high-pressure speed after the measured high-pressure speed meets the high-pressure speed limited by the fuel supply condition, and then determine the given equivalent oil-gas ratio corresponding to the current high-pressure conversion speed.

[0023] Preferably, the fuel supply set value adjustment module includes a timing ignition unit, which is used to ignite the engine when the time for adjusting the fuel supply set value exceeds the forced ignition fuel supply time.

[0024] This application effectively solves the problem of engine ignition stall caused by initial overshoot of the fuel supply accessories, improves the engine ignition reliability, and is compatible with the ignition impact caused by the dispersion of engine state during ignition. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a preferred embodiment of the ignition fuel supply method based on oil-gas ratio control of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the implementation of this application will be described in more detail below in conjunction with the drawings in the implementation of this application. In the drawings, the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and should not be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in conjunction with the drawings.

[0027] The first aspect of the present application provides an ignition fuel supply method based on oil-gas ratio control, such as Figure 1 As shown, it mainly includes:

[0028] Step S1: Calculate the initial set fuel flow rate based on a given equivalent fuel-gas ratio and a combustion chamber inlet pressure, and supply fuel to the combustion chamber as the given fuel supply value. The equivalent fuel-gas ratio refers to the ratio of the engine fuel flow rate to the combustion chamber inlet pressure.

[0029] Since the ignition boundary of the combustion chamber of an aircraft engine is greatly affected by the oil-gas ratio during ignition, the present application determines the fuel supply to the combustion chamber by the oil-gas ratio in step S1. It should be noted that the present application first proposed the equivalent oil-gas ratio in step S1, which refers to the engine fuel flow rate W f and the combustion chamber inlet pressure P in The ratio is used to replace the traditional oil-air ratio, because the traditional oil-air ratio refers to the engine fuel flow W f The ratio of the combustion chamber inlet flow rate Q to the combustion chamber inlet flow rate Q is generally impossible to measure. The combustion chamber inlet flow rate Q is related to the combustion chamber inlet pressure P. in There is a certain linear relationship, so the combustion chamber inlet pressure P is used in Replace the combustion chamber inlet flow Q and construct a new equivalent oil-gas ratio.

[0030] Specifically, the calculation formula for the combustion chamber inlet flow rate Q is as follows:

[0031]

[0032] Where K is the constant used when calculating the flow rate using the flow aerodynamic function; A is the combustion chamber inlet area, which is a fixed value for the same model; is the velocity coefficient, which changes very little at the combustion chamber inlet before ignition; T in is the total temperature at the combustion chamber inlet. According to the above formula, and When the change is small and K and A are constant, the measurable combustion chamber inlet pressure P can be selected. in Instead of the combustion chamber inlet flow Q.

[0033] In some optional embodiments, step S1 further includes:

[0034] Step S11: constructing a relationship between the equivalent fuel-gas ratio and the high-pressure converted speed, and determining the equivalent fuel-gas ratio boundary for each high-pressure converted speed that enables engine ignition;

[0035] Step S12: for each high-pressure converted speed, the middle value within the boundary range of the equivalent fuel-gas ratio is used as the given equivalent fuel-gas ratio;

[0036] Step S13: After the measured high-pressure speed meets the high-pressure speed limit of the oil supply condition, the high-pressure converted speed is calculated according to the measured high-pressure speed, and the given equivalent oil-gas ratio corresponding to the current high-pressure converted speed is determined.

[0037] In step S13, when the engine enters the starting process and the high-pressure speed n2 is greater than or equal to the high-pressure speed n2 limited by the fuel supply condition, 2允许供油转速 After that, start measuring the high-voltage speed n of the current cycle 2当前周期and the total temperature of the engine inlet T 1当前周期 , and then calculate the high-voltage conversion speed n of the current cycle by the following formula 2r当前周期 Then, based on the intermediate value of the ignition boundary determined in step S12, the given equivalent fuel-air ratio f corresponding to the current high-pressure conversion speed is determined. wf_Pin (n 2r当前周期 ).

[0038] It should be noted that the total temperature of the engine inlet, in K, can be obtained by sensor measurement, n 2允许供油转速 It needs to be determined according to different engine types, determined by the combustion chamber inlet state and the fuel supply accessories capacity. With the above given equivalent oil-gas ratio f wf_Pin (n 2r当前周期 ), the initial oil flow rate W can be calculated by the following formula fDem初始 , and supplies fuel to the combustion chamber as the fuel supply set value:

[0039] W fDem初始 =f wf_Pin (n 2r当前周期 )*P in当前周期 ;

[0040] Among them, P in当前周期 is the combustion chamber inlet pressure of the current cycle.

[0041] Step S2: Calculate the actual equivalent fuel-gas ratio based on the actual fuel flow rate and the combustion chamber inlet pressure of the current cycle.

[0042] At the initial moment, fuel is supplied to the combustion chamber according to the fuel supply set value calculated in step S1, but it cannot guarantee that the actual fuel supply amount will be consistent with the fuel supply set value immediately. Therefore, it is necessary to calculate the actual fuel supply flow rate W in step S2. f当前周期 and combustion chamber inlet pressure P in当前周期 Calculate the actual equivalent oil-gas ratio yqb 当前周期 :

[0043] yqb 当前周期 =W f当前周期 / P in当前周期 .

[0044] In this step, the engine fuel flow rate can be obtained through relevant measurement parameters in the fuel accessories, such as accessories such as a metering valve.

[0045] Step S3: When the actual equivalent oil-gas ratio is greater than the given equivalent oil-gas ratio, the fuel supply given value is reduced according to the set fuel supply change rate; conversely, when the actual equivalent oil-gas ratio is less than the given equivalent oil-gas ratio, the fuel supply given value is increased according to the set fuel supply change rate.

[0046] Step S4: During the process of increasing the fuel supply set value, when the actual equivalent fuel-gas ratio of the current cycle is less than the given equivalent fuel-gas ratio and the actual equivalent fuel-gas ratio of the current cycle is greater than or equal to the given equivalent fuel-gas ratio, ignite the engine.

[0047] In step S3 and step S4, when the actual equivalent fuel-air ratio yqb of the engine is 当前周期 When the fuel-air ratio is higher than the ideal ignition fuel-air ratio of the engine, that is, higher than the given equivalent fuel-air ratio f wf_Pin (n 2r当前周期 ) is high, reduce oil at a certain rate until the equivalent oil-gas ratio f wf_Pin (n 2r当前周期 ) is low, refuel; when it exceeds the given equivalent oil-gas ratio f again wf_Pin (n 2r当前周期 ), an ignition command is issued to start ignition, thereby ensuring that the fuel-air ratio is within the appropriate range during ignition. The fuel supply change rate can be set according to the engine's own margin.

[0048] In some optional embodiments, step S3 further includes igniting the engine when the time for adjusting the fuel supply set value exceeds the forced ignition fuel supply time.

[0049] In addition to the ignition conditions given in step S4, when the forced ignition and fuel supply time is exceeded, ignition and fuel supply must be performed after reaching this time; the forced ignition and fuel supply time needs to be determined according to the starting time requirements of different engines.

[0050] When the ignition is successful, the control logic is exited. For example, the ignition success can be determined by monitoring the exhaust temperature, or after the forced ignition and fuel supply time is reached, the control logic is exited after the ignition is executed.

[0051] This application can effectively solve the problem of engine ignition stall caused by initial overshoot of the fuel supply accessories, improve the engine ignition reliability, and be compatible with the ignition impact caused by the dispersion of engine state during ignition.

[0052] The second aspect of the present application provides an ignition fuel supply device based on oil-gas ratio control corresponding to the above method, mainly comprising:

[0053] A fuel supply setpoint initialization module is used to calculate an initial set fuel supply flow rate based on a given equivalent fuel-to-air ratio and a combustion chamber inlet pressure, and to supply fuel to the combustion chamber as the fuel supply setpoint value. The equivalent fuel-to-air ratio refers to the ratio of the engine fuel flow rate to the combustion chamber inlet pressure.

[0054] The actual equivalent fuel-gas ratio calculation module is used to calculate the actual equivalent fuel-gas ratio based on the actual fuel flow rate and combustion chamber inlet pressure of the current cycle;

[0055] a fuel supply set value adjustment module, configured to reduce the fuel supply set value at a set fuel supply change rate when the actual equivalent fuel-gas ratio is greater than the given equivalent fuel-gas ratio; and conversely, increase the fuel supply set value at a set fuel supply change rate when the actual equivalent fuel-gas ratio is less than the given equivalent fuel-gas ratio;

[0056] The engine ignition module is used to ignite the engine when the actual equivalent fuel-gas ratio of the previous cycle is less than the given equivalent fuel-gas ratio and the actual equivalent fuel-gas ratio of the current cycle is greater than or equal to the given equivalent fuel-gas ratio during the process of increasing the fuel supply set value.

[0057] In some optional implementations, the fuel supply setpoint initialization module includes:

[0058] An equivalent fuel-gas ratio construction unit is used to construct a relationship between the equivalent fuel-gas ratio and the high-pressure converted speed, and determine the equivalent fuel-gas ratio boundary that enables engine ignition corresponding to each high-pressure converted speed;

[0059] A given equivalent fuel-gas ratio construction unit is used to take, for each high-pressure converted speed, an intermediate value within the equivalent fuel-gas ratio boundary range as the given equivalent fuel-gas ratio;

[0060] The given equivalent oil-gas ratio determination unit is used to calculate the high-pressure conversion speed based on the measured high-pressure speed after the measured high-pressure speed meets the high-pressure speed limited by the fuel supply condition, and then determine the given equivalent oil-gas ratio corresponding to the current high-pressure conversion speed.

[0061] In some optional embodiments, the fuel supply set value adjustment module includes a timing ignition unit, which is used to ignite the engine when the time for adjusting the fuel supply set value exceeds the forced ignition fuel supply time.

[0062] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An ignition fuel supply method based on oil-gas ratio control, characterized in that: include: Step S1: Calculating an initial fuel flow rate based on a given equivalent fuel-to-air ratio and a combustion chamber inlet air pressure, and supplying fuel to the combustion chamber as a given fuel supply value; wherein the equivalent fuel-to-air ratio refers to the ratio of the engine fuel flow rate to the combustion chamber inlet air pressure; Step S2: Calculate the actual equivalent fuel-gas ratio based on the actual fuel flow rate and the combustion chamber inlet air pressure of the current cycle; Step S3: when the actual equivalent oil-gas ratio is greater than the given equivalent oil-gas ratio, the fuel supply set value is reduced according to the set fuel supply change rate; conversely, when the actual equivalent oil-gas ratio is less than the given equivalent oil-gas ratio, the fuel supply set value is increased according to the set fuel supply change rate; Step S4: During the process of increasing the fuel supply set value, when the actual equivalent fuel-gas ratio of the current cycle is less than the given equivalent fuel-gas ratio and the actual equivalent fuel-gas ratio of the current cycle is greater than or equal to the given equivalent fuel-gas ratio, ignite the engine.

2. The ignition fuel supply method based on oil-gas ratio control according to claim 1, characterized in that: Before step S1, the method further includes: Step S11: constructing a relationship between the equivalent fuel-gas ratio and the high-pressure converted speed, and determining the equivalent fuel-gas ratio boundary for each high-pressure converted speed that enables engine ignition; Step S12: for each high-pressure converted speed, the middle value within the boundary range of the equivalent fuel-gas ratio is used as the given equivalent fuel-gas ratio; Step S13: After the measured high-pressure speed meets the high-pressure speed limit of the oil supply condition, the high-pressure converted speed is calculated according to the measured high-pressure speed, and the given equivalent oil-gas ratio corresponding to the current high-pressure converted speed is determined.

3. The ignition fuel supply method based on oil-gas ratio control according to claim 1, characterized in that: Step S3 further includes igniting the engine when the time for adjusting the fuel supply set value exceeds the forced ignition fuel supply time.

4. An ignition oil supply device based on oil-gas ratio control, characterized in that: include: a fuel supply setpoint initialization module, configured to calculate an initial set fuel supply flow rate based on a given equivalent fuel-to-air ratio and the combustion chamber inlet air pressure, and supply fuel to the combustion chamber as the fuel supply setpoint value; The actual equivalent fuel-gas ratio calculation module is used to calculate the actual equivalent fuel-gas ratio based on the actual fuel flow rate and combustion chamber inlet air pressure of the current cycle; a fuel supply set value adjustment module, configured to reduce the fuel supply set value at a set fuel supply change rate when the actual equivalent fuel-gas ratio is greater than the given equivalent fuel-gas ratio; and conversely, increase the fuel supply set value at a set fuel supply change rate when the actual equivalent fuel-gas ratio is less than the given equivalent fuel-gas ratio; The engine ignition module is used to ignite the engine when the actual equivalent fuel-gas ratio of the previous cycle is less than the given equivalent fuel-gas ratio and the actual equivalent fuel-gas ratio of the current cycle is greater than or equal to the given equivalent fuel-gas ratio during the process of increasing the fuel supply set value.

5. The ignition oil supply device based on oil-gas ratio control according to claim 4, characterized in that: The fuel supply set value initial setting module includes: An equivalent fuel-gas ratio construction unit is used to construct a relationship between the equivalent fuel-gas ratio and the high-pressure converted speed, and determine the equivalent fuel-gas ratio boundary that enables engine ignition corresponding to each high-pressure converted speed; A given equivalent fuel-gas ratio construction unit is used to take, for each high-pressure converted speed, an intermediate value within the equivalent fuel-gas ratio boundary range as the given equivalent fuel-gas ratio; The given equivalent oil-gas ratio determination unit is used to calculate the high-pressure conversion speed based on the measured high-pressure speed after the measured high-pressure speed meets the high-pressure speed limited by the fuel supply condition, and then determine the given equivalent oil-gas ratio corresponding to the current high-pressure conversion speed.

6. The ignition oil supply device based on oil-gas ratio control according to claim 4, characterized in that: The fuel supply set value adjustment module includes a timing ignition unit, which is used to ignite the engine when the time for adjusting the fuel supply set value exceeds the forced ignition fuel supply time.

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