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

Abstract

The invention belongs to the technical field of engine control, and particularly relates to an ignition oil supply method and device based on oil-gas ratio control, and the method comprises the following steps: S1, calculating an initially set oil supply flow according to a given equivalent oil-gas ratio and inlet pressure of a combustion chamber, and supplying oil to the combustion chamber as an oil supply given value; s2, the actual equivalent oil-gas ratio is calculated according to the actual oil supply flow of the current period and the inlet pressure of the combustion chamber; s3, when the actual equivalent oil-gas ratio is larger than the given equivalent oil-gas ratio, the oil supply given value is reduced according to the set oil supply change rate, and otherwise, the oil supply given value is increased according to the set oil supply change rate; and S4, in the process of increasing the oil supply given value, when the actual equivalent oil-gas ratio of the current period is smaller than the given equivalent oil-gas ratio and the actual equivalent oil-gas ratio of the current period is larger than or equal to the given equivalent oil-gas ratio, the engine is ignited. The ignition reliability of the engine is improved.

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] At present, the initial fuel supply for most aircraft engines is open-loop control (the absolute amount of initial fuel supply is given according to the atmospheric pressure or the inlet pressure of the combustion chamber, and then no longer corrected according to the engine status). None of them considers the problem of excessive fuel supply caused by the initial overshoot of the fuel supply accessories and the dispersion of the engine itself (the problem of different gas volume differences during ignition) when the engine is ignited. There may be problems such as ignition stall caused by a rich oil-gas ratio, or ignition failure caused by a lean oil-gas ratio. For some advanced electronically controlled engines, they use a "progressive" fuel supply method (the initial fuel supply is set at a low value, and fuel is added at a certain rate before ignition fails, until the oil-gas ratio is suitable for ignition success). This method can solve the problem of ignition failure caused by insufficient fuel supply of accessories, but it cannot solve the problem of ignition stall caused by excessive initial overshoot of the fuel supply accessories and the dispersion of the engine itself. 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] The first aspect of the present application provides an ignition fuel supply method based on oil-gas ratio control, which mainly includes:

[0005] Step S1, calculating an initially set fuel flow rate according to 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, wherein the equivalent fuel-gas ratio refers to a ratio of the engine fuel flow rate to the combustion chamber inlet pressure;

[0006] Step S2, calculating the actual equivalent oil-gas ratio according to the actual oil supply 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 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;

[0008] Step S4: in the process of increasing the fuel supply given 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, before step S1, the method further comprises:

[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 conversion speed, taking the middle value within the boundary range of the equivalent oil-gas ratio as the given equivalent oil-gas ratio;

[0012] Step S13: after the measured high-pressure speed meets the high-pressure speed limited by the fuel supply condition, the high-pressure converted speed is calculated according to the measured high-pressure speed, and then 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 set value initial setting module, used to calculate the initial set fuel supply flow rate according to a given equivalent fuel-gas ratio and a combustion chamber inlet pressure, and supply fuel to the combustion chamber as the fuel supply set value, wherein the equivalent fuel-gas 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 according to the actual fuel supply flow rate and the combustion chamber inlet pressure of the current cycle;

[0017] A fuel supply set value adjustment module, used for reducing the fuel supply set value according to a set fuel supply change rate when the actual equivalent fuel-gas ratio is greater than the given equivalent fuel-gas ratio, and conversely, increasing the fuel supply set value according to the 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 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 during the process of increasing the given fuel supply 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 conversion speed, and determine the equivalent fuel-gas ratio boundary corresponding to each high-pressure conversion speed for engine ignition;

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

[0022] The given equivalent oil-gas ratio determination unit is used to calculate the high-pressure conversion speed according to 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 for igniting the engine when the time for adjusting the fuel supply set value exceeds the forced ignition fuel supply time.

[0024] The present application effectively solves the problem of engine ignition stall caused by initial overshoot of the fuel supply accessories, improves the reliability of engine ignition, and is compatible with the ignition influence 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 scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals 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 cannot 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 combination 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, calculating the initially set fuel flow rate according to 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, wherein 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 proposes the equivalent oil-gas ratio in step S1, which refers to the engine fuel flow rate W f The combustion chamber inlet pressure P in The ratio is used to replace the traditional oil-gas ratio. This is because the traditional oil-gas ratio refers to the engine fuel flow rate W f The ratio of the combustion chamber inlet flow rate Q to the combustion chamber inlet pressure P is the same as the ratio of the combustion chamber inlet flow rate Q 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 fuel-gas ratio.

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

[0031]

[0032] Among them, 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 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 Replace the combustion chamber inlet flow Q.

[0033] In some optional implementations, the 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 conversion speed, taking the middle value within the boundary range of the equivalent oil-gas ratio as the given equivalent oil-gas ratio;

[0036] Step S13: after the measured high-pressure speed meets the high-pressure speed limited by the fuel supply condition, the high-pressure converted speed is calculated according to the measured high-pressure speed, and then 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 n 2 Greater than or equal to the high pressure speed n 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 cycle2当前周期 The total temperature of the engine inlet is 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-gas 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 measuring the sensor, 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 accessory capacity. With the above given equivalent fuel-gas ratio f wf_Pin (n 2r当前周期 ), the initial oil supply flow rate W can be calculated by the following formula fDem初始 , and supplies fuel to the combustion chamber as the fuel supply setpoint:

[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, calculating the actual equivalent fuel-gas ratio according to the actual fuel supply flow rate and the combustion chamber inlet pressure of the current cycle.

[0042] At the initial moment, supplying fuel to the combustion chamber according to the fuel supply set value calculated in step S1 cannot ensure that the actual fuel supply amount is immediately consistent with the fuel supply set value. 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 through 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: in the process of increasing the fuel supply given 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-gas ratio of the engine is yqb 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 lower, refuel again; 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-gas ratio is within a suitable 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 success of the ignition 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] The present application can effectively solve the problem of engine ignition stall caused by initial overshoot of the fuel supply accessories, improve the reliability of engine ignition, and be compatible with the ignition influence 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 set value initial setting module, used to calculate the initial set fuel supply flow rate according to a given equivalent fuel-gas ratio and a combustion chamber inlet pressure, and supply fuel to the combustion chamber as the fuel supply set value, wherein the equivalent fuel-gas 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 according to the actual fuel supply flow rate and the combustion chamber inlet pressure of the current cycle;

[0055] A fuel supply set value adjustment module, used for reducing the fuel supply set value according to a set fuel supply change rate when the actual equivalent fuel-gas ratio is greater than the given equivalent fuel-gas ratio, and conversely, increasing the fuel supply set value according to the 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 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 during the process of increasing the given fuel supply value.

[0057] In some optional implementations, the fuel supply setpoint initial setting 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 conversion speed, and determine the equivalent fuel-gas ratio boundary corresponding to each high-pressure conversion speed for engine ignition;

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

[0060] The given equivalent oil-gas ratio determination unit is used to calculate the high-pressure conversion speed according to 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 is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An ignition fuel supply method based on oil-gas ratio control, characterized in that: include: Step S1, calculating an initially set fuel flow rate according to 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, wherein the equivalent fuel-gas ratio refers to a ratio of the engine fuel flow rate to the combustion chamber inlet pressure; Step S2, calculating the actual equivalent oil-gas ratio according to the actual oil 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, 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; Step S4: in the process of increasing the fuel supply given 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 comprises: 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 conversion speed, taking the middle value within the boundary range of the equivalent oil-gas ratio as the given equivalent oil-gas ratio; Step S13: after the measured high-pressure speed meets the high-pressure speed limited by the fuel supply condition, the high-pressure converted speed is calculated according to the measured high-pressure speed, and then 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 fuel supply device based on oil-gas ratio control, characterized in that: include: A fuel supply set value initial setting module, used to calculate the initial set fuel supply flow rate according to a given equivalent fuel-gas ratio and a combustion chamber inlet pressure, and supply fuel to the combustion chamber as the fuel supply set value, wherein the equivalent fuel-gas ratio refers to the ratio of the engine fuel flow rate to the combustion chamber inlet pressure; The actual equivalent fuel-gas ratio calculation module is used to calculate the actual equivalent fuel-gas ratio according to the actual fuel supply flow rate and the combustion chamber inlet pressure of the current cycle; A fuel supply set value adjustment module, used for reducing the fuel supply set value according to a set fuel supply change rate when the actual equivalent fuel-gas ratio is greater than the given equivalent fuel-gas ratio, and conversely, increasing the fuel supply set value according to the 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 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 during the process of increasing the given fuel supply value.

5. The ignition fuel supply device based on oil-gas ratio control according to claim 4, characterized in that: The fuel supply setpoint initial setting module comprises: An equivalent fuel-gas ratio construction unit is used to construct a relationship between the equivalent fuel-gas ratio and the high-pressure conversion speed, and determine the equivalent fuel-gas ratio boundary corresponding to each high-pressure conversion speed for engine ignition; A given equivalent fuel-gas ratio construction unit is used to take the middle value within the boundary range of the equivalent fuel-gas ratio as the given equivalent fuel-gas ratio for each high pressure conversion speed; The given equivalent oil-gas ratio determination unit is used to calculate the high-pressure conversion speed according to 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 fuel 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.

Images