Method, device, system and equipment for detecting early burning explosion of aero-engine

Abstract

The invention provides a method, a device, a system and equipment for detecting early burning explosion of an aero-engine. A method for detecting early burning and explosion of an aero-engine comprises the steps that S1, the slope calculation time range of the exhaust temperature EGT is set to be SCnt, the typical value is set to be 7, the unit is second, an engine exhaust temperature EGT slope calculation one-dimensional array is established to be EGTKCalcArr, the size of the array is SCnt * 7, and an engine cylinder head temperature CHT slope calculation one-dimensional array is established, and the size of the array is SCnt * 7; and S2, the line number of the currently read engine data is set as lineNum, 1 is added to lineNum every time a line of data of the engine data is read, the exhaust temperatures of the first cylinder to the sixth cylinder in each line of the engine data are set as EGT1 to EGT6, and the cylinder head temperatures of the first cylinder to the sixth cylinder are set as CHT1 to CHT6. According to the invention, the early burning and explosion detection accuracy and efficiency of the aero-engine are improved, missed diagnosis caused by knowledge difference between aircraft maintenance personnel and hidden dangers caused by untreated aircrafts with early burning and explosion are effectively avoided, and the aviation safety is effectively ensured.

Description

Technical Field

[0001] The present invention relates to the field of aircraft maintenance technology, and more particularly to a method, device, system and equipment for detecting early combustion and knock of an aircraft engine. Background Art

[0002] The SR20 aircraft produced by the American Cirrus Design Company is known as the "BMW of the sky". It adopts a composite material structure and is equipped with a parachute system. It has excellent flight quality and high safety. It has been widely used in private use and flight training. The number of Cirrus' SR series aircraft in the world has exceeded 6,000. The Cirrus SR20 aircraft is equipped with the IO360ES aviation 6-cylinder piston engine produced by the American TCM Company. Due to design problems, this type of engine is more prone to premature combustion and detonation than the Lycoming engine. The manufacturer has made many improvements to the design and replaced many parts, but has not fundamentally solved the problem of premature combustion and detonation in this engine. Premature combustion and detonation of the engine is an abnormal explosive combustion. Depending on its intensity and duration, it will cause irreversible damage to the engine. If it is not discovered and necessary maintenance is not carried out in time, the aircraft that has experienced premature combustion and detonation but has not been identified and handled in time will fly with hidden dangers. As the damage further expands, the aircraft may have engine shutdown in the air at any time, resulting in the destruction of the aircraft and the death of people. Summary of the invention

[0003] The purpose of the present invention is to provide a method, device, system and equipment for detecting early combustion and knock of an aircraft engine.

[0004] The present invention aims to solve the problems existing in the prior art.

[0005] Compared with the prior art, the technical solution of the present invention and its beneficial effects are as follows:

[0006] The first aspect of the present invention provides a method for detecting early combustion and knock of an aircraft engine, comprising:

[0007] S1, set the slope calculation time range of exhaust temperature EGT to S_Cnt, the typical value is 7, the unit is seconds, establish an engine exhaust temperature EGT slope calculation one-dimensional array EGT_KCalc_Arr, the size of the array is S_Cnt*7, establish an engine cylinder head temperature CHT slope calculation one-dimensional array CHT_KCalc_Arr, the size of the array is S_Cnt*7;

[0008] S2, setting the row number of the currently read engine data as lineNum, and increasing lineNum by 1 for each row of engine data, and setting the exhaust temperatures of cylinders 1 to 6 in each row of engine data as EGT1 to EGT6, and the cylinder head temperatures of cylinders 1 to 6 as CHT1 to CHT6;

[0009] S3, calculate the exhaust gas temperature EGT "mainstream value" of the six cylinders in each row of engine data, the cylinder head temperature CHT "mainstream value" of the six cylinders, and the cylinder head temperature CHT of the six cylinders at the current time t t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at the current time t minus 6 seconds (t-6)_n The "mainstream value" of the angle between the straight line formed by the two points and the horizontal line;

[0010] S4, for any cylinder number n, use the least square method to perform straight line fitting on the exhaust temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second, and calculate the slopes of the fitting lines to be K_EGT_n and K_CHT_n respectively;

[0011] S5, set the n cylinder exhaust temperature EGT early combustion knock start diagnosis flag to ZRBZ_Sign_EGT_n, the default value is 0, set the n cylinder exhaust temperature EGT early combustion knock diagnosis internal count to EGT_Ovr_cnt_n, the default value is 0; set the exhaust temperature EGT n Curve judgment condition 1;

[0012] S6, at exhaust gas temperature EGT n Comply with exhaust gas temperature EGT n When the curve judgment condition is 1 and the current value of ZRBZ_Sign_EGT_n is 1, the cylinder head temperature CHT is set n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition two, by judging whether the condition is met, it is determined whether there is pre-ignition knock in cylinder n at the moment of the current data row.

[0013] A second aspect of the present invention provides a device for detecting early combustion and knock of an aircraft engine, comprising:

[0014] The first setting module is configured to set the slope calculation time range of the exhaust temperature EGT to S_Cnt, with a typical value of 7, in seconds, to establish an engine exhaust temperature EGT slope calculation one-dimensional array EGT_KCalc_Arr, the size of which is S_Cnt*7, and to establish an engine cylinder head temperature CHT slope calculation one-dimensional array CHT_KCalc_Arr, the size of which is S_Cnt*7;

[0015] The second setting module is configured to set the row number of the currently read engine data as lineNum, and each time a row of engine data is read, lineNum is increased by 1, and the exhaust temperature of cylinders 1 to 6 in each row of engine data is set to EGT1 to EGT6, and the cylinder head temperature of cylinders 1 to 6 is set to CHT1 to CHT6;

[0016] The first calculation module is configured to calculate the exhaust gas temperature EGT "mainstream value" of the six cylinders in each row of engine data, the cylinder head temperature CHT "mainstream value" of the six cylinders, and the cylinder head temperature CHT of the six cylinders at the current time t. t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at the current time t minus 6 seconds (t-6)_n The "mainstream value" of the angle between the straight line formed by the two points and the horizontal line;

[0017] The second calculation module is configured to use the least square method to perform a straight line fitting on the exhaust temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second for any cylinder number n, and obtain the slopes of the fitting straight lines as K_EGT_n and K_CHT_n respectively;

[0018] The third setting module is configured to set the n cylinder exhaust temperature EGT early combustion knock start diagnosis flag to ZRBZ_Sign_EGT_n, the default value is 0, set the n cylinder exhaust temperature EGT early combustion knock diagnosis internal count to EGT_Ovr_cnt_n, the default value is 0; set the exhaust temperature EGT n Curve judgment condition 1;

[0019] The judgment module is configured to determine the exhaust gas temperature EGT n Comply with exhaust gas temperature EGT n When the curve judgment condition is 1 and the current value of ZRBZ_Sign_EGT_n is 1, the cylinder head temperature CHT is set n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition two, by judging whether the condition is met, it is determined whether there is pre-ignition knock in cylinder n at the moment of the current data row.

[0020] The third aspect of the present invention provides a system for detecting pre-ignition and knock of an aircraft engine, which comprises at least a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps of a method for detecting pre-ignition and knock of an aircraft engine when executing the computer program in the memory.

[0021] A fourth aspect of the present invention provides an electronic device, including a computer program, which, when executed by a processor, implements the method for detecting pre-ignition knock of an aircraft engine.

[0022] The beneficial effects of the present invention are:

[0023] The present invention discloses an exhaust gas temperature (EGT) and cylinder head temperature (CHT) data of an engine recorded by an SD data card in a G1000 system of an SR20 aircraft. Any other recorded data that can provide the exhaust gas temperature and cylinder head temperature of the engine in seconds can be detected using the method disclosed in the present invention. For example, if the engine is not installed on an aircraft but is tested on a test bench after overhaul, but the test bench can record CHT and exhaust gas temperature EGT in seconds, the method can also be used for detection. The detection method is fast and accurate, and can greatly improve the accuracy and efficiency of TCM IO360ES's early combustion and knock detection, and can effectively avoid missed diagnosis caused by knowledge differences between aircraft maintenance personnel and avoid aircraft that have experienced early combustion and knock from taking to the sky without processing hidden dangers, thereby effectively ensuring aviation safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a method for detecting pre-ignition and knock of an aircraft engine provided by an embodiment of the present invention.

[0025] Figure 2 It is a first schematic diagram of cylinder pre-ignition and knock where some curves are provided in an embodiment of the present invention.

[0026] Figure 3 It is a second schematic diagram of cylinder pre-ignition and knock where part of the curves provided in an embodiment of the present invention are located. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0029] Reference Figures 1 to 3 As shown, a method for detecting early combustion and knock of an aircraft engine comprises:

[0030] S1, set the slope calculation time range of exhaust temperature EGT to S_Cnt, the typical value is 7, the unit is seconds, establish an engine exhaust temperature EGT slope calculation one-dimensional array EGT_KCalc_Arr, the size of the array is S_Cnt*7, establish an engine cylinder head temperature CHT slope calculation one-dimensional array CHT_KCalc_Arr, the size of the array is S_Cnt*7;

[0031] S2, setting the row number of the currently read engine data as lineNum, and increasing lineNum by 1 for each row of engine data, and setting the exhaust temperatures of cylinders 1 to 6 in each row of engine data as EGT1 to EGT6, and the cylinder head temperatures of cylinders 1 to 6 as CHT1 to CHT6;

[0032] S3, calculate the exhaust gas temperature EGT "mainstream value" of the six cylinders in each row of engine data, the cylinder head temperature CHT "mainstream value" of the six cylinders, and the cylinder head temperature CHT of the six cylinders at the current time t t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at the current time t minus 6 seconds (t-6)_n The "mainstream value" of the angle between the straight line formed by the two points and the horizontal line;

[0033] S4, for any cylinder number n, use the least square method to perform straight line fitting on the exhaust temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second, and calculate the slopes of the fitting lines to be K_EGT_n and K_CHT_n respectively;

[0034] S5, set the n cylinder exhaust temperature EGT early combustion knock start diagnosis flag to ZRBZ_Sign_EGT_n, the default value is 0, set the n cylinder exhaust temperature EGT early combustion knock diagnosis internal count to EGT_Ovr_cnt_n, the default value is 0; set the exhaust temperature EGT n Curve judgment condition 1;

[0035] S6, at exhaust gas temperature EGT n Comply with exhaust gas temperature EGTn When the curve judgment condition is 1 and the current value of ZRBZ_Sign_EGT_n is 1, the cylinder head temperature CHT is set n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition two, by judging whether the condition is met, it is determined whether there is pre-ignition knock in cylinder n at the moment of the current data row.

[0036] In step S2, the row number of the currently read engine data is set as lineNum, and each time a row of engine data is read, lineNum is increased by 1, and the exhaust temperatures of cylinders 1 to 6 in each row of engine data are set as EGT1 to EGT6, and the cylinder head temperatures of cylinders 1 to 6 are set as CHT1 to CHT6, wherein the following is also included:

[0037] Assume that the latest data storage index of the exhaust temperature EGT slope calculation one-dimensional array is Index1, and Index1 is equal to the remainder of lineNum divided by S_Cnt;

[0038] Assume that the oldest data storage index of the exhaust temperature EGT slope calculation one-dimensional array is Index2, and Index2 is equal to the remainder of Index1 plus 1 divided by S_Cnt;

[0039] Each time a row of engine data is read, the exhaust temperature EGT of cylinder n (0≤n≤6) is calculated. n Put it into the EGT_KCalc_Arr array [S_Cnt*(n-1)+Index1] index position, and put the cylinder head temperature CHT of cylinder n (0≤n≤6) n Put it into the CHT_KCalc_Arr array at the index position [S_Cnt*(n-1)+Index1].

[0040] In step S3, the cylinder head temperatures CHT of the six cylinders at the current time t are calculated. t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at the current time t minus 6 seconds (t-6)_n The angle between the straight line formed by the two points and the horizontal line, wherein the angle is calculated by arctan{[(CHT t_n -CHT (t-6)_n ) / 6]}*180 / π.

[0041] In step S3, it also includes:

[0042] The mainstream values ​​are the calculated "virtual exhaust temperature", "virtual cylinder head temperature" and "virtual mainstream cylinder head temperature curve angle". These three "virtual values" can reflect the mainstream levels of exhaust temperature and cylinder head temperature and "instantaneous changes in exhaust temperature curve" in each line of engine data. They are the reference temperatures and angles for subsequent judgment and identification of abnormal exhaust temperature and cylinder head temperature.

[0043] The exhaust temperatures EGT1 to EGT6 of the six cylinders, the cylinder head temperatures CHT1 to CHT6, and the cylinder head temperatures CHT t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at t-6 seconds (t-6)_n The angle between the straight line formed by the two points and the horizontal line is The permutations and combinations of the data are divided into 15 groups respectively. The variances of the data within these 15 groups are compared. The group with the smallest variance is selected. If there are two or more groups with the same variance, the group with the smallest difference between the highest and lowest values ​​is selected. If there are still two or more groups with the same difference between the highest and lowest values, the group with the lowest absolute value of the smallest value is selected. The average of the four values ​​in this group is the "mainstream value".

[0044] In step S3, it also includes:

[0045] Set the exhaust temperature EGT "mainstream value" of the 6 cylinders to IntensiveEGT and put it into the index position of the EGT_KCalc_Arr array (S_Cnt*6+Index1);

[0046] Put the "mainstream value" of the cylinder head temperature CHT of the 6 cylinders into the index position of the CHT_KCalc_Arr array [S_Cnt*6+Index1].

[0047] In the step S4, it also includes:

[0048] In the EGT_KCalc_Arr and CHT_KCalc_Arr arrays, the "mainstream values" of the exhaust temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second are respectively used to calculate the "standard slopes" stdK_EGT and stdK_CHT of the "mainstream values" of the exhaust temperature EGT and the cylinder head temperature CHT in the fitting straight line by the least squares method; the virtual curve composed of the mainstream values ​​of EGT and the mainstream values ​​of the cylinder head temperature CHT is the "mainstream curve" calculated in step S3, and the pre-ignition knock is detected by comparing the difference or change between the real curve of the exhaust temperature EGT or the cylinder head temperature CHT of each cylinder and the "mainstream curve".

[0049] Calculate the angle EGTJiajiao between the slope of the fitted straight line K_EGT_n and the standard slope stdK_EGT of the exhaust temperature of cylinder n n =arctan[(K_EGT_n-stdK_EGT) / (1+K_EGT_n*stdK_EGT)];

[0050] Calculate the angle CHTjiaodu between the fitted straight line and the horizontal line of the cylinder head temperature of cylinder n n =arctan(K_CHT_n) and the angle between the mainstream fitting straight line of the cylinder head temperature and the horizontal line std_CHTjiaodu=arctan(stdK_CHT).

[0051] In step S5, it also includes:

[0052] Set exhaust gas temperature EGT n Curve judgment condition 1: K_EGT_n is greater than stdK_EGT and K_EGT_n is greater than 0.81 and EGT is equal to n Greater than or equal to 40°, or the current value of ZRBZ_Sign_EGT_n is 1 and the row number of the data row where the current diagnosis is located is less than 150 from the row number of the row where ZRBZ_Sign_EGT_n was last changed from 0 to 1, that is, no more than 150 seconds, and the exhaust temperature of the current cylinder n is higher than or equal to the exhaust temperature "mainstream value" by more than 50 degrees Fahrenheit, and when K_EGT_n is less than or equal to 0, that is, the exhaust temperature EGT curve falls back, the exhaust temperature EGT pre-ignition knock diagnosis internal count EGT_Ovr_cnt_n is still less than 6;

[0053] If the exhaust gas temperature EGT n The current curve corresponds to the exhaust gas temperature EGT n Curve judgment condition 1: If the current value of ZRBZ_Sign_EGT_n is 0, then set ZRBZ_Sign_EGT_n to 1. n When it is greater than or equal to 40°, EGT_Ovr_cnt_n increases by 1. If EGTJiajiao n If it is less than 40° and EGT_Ovr_cnt_n is less than 6 at the same time, set EGT_Ovr_cnt_n to 0 and restart counting.

[0054] In step S6, it also includes:

[0055] Set the cylinder head temperature CHT n Curve judgment condition 1: CHTjiaodu n Greater than or equal to 20° and CHTjiaodu nSubtract std_CHTjiaodu greater than or equal to 20°;

[0056] Set the cylinder head temperature CHT n Curve judgment condition 2: CHTjiaodu at the current moment n Subtract CHTjiaodu from the previous second n_(t-1) Greater than or equal to -2°, that is, the cylinder head temperature CHT rises and does not fall back. If it falls back, the rate of fall is no more than 2 degrees Fahrenheit / second;

[0057] Set the cylinder head temperature CHT curve early combustion knock start diagnosis flag ZRBZ_Sign_CHT_n of the cylinder, the default value is 0, set the exhaust temperature EGT early combustion knock diagnosis internal count to CHT_Ovr_cnt_n, the default value is 0;

[0058] If the current cylinder head temperature CHT n At the same time, the cylinder head temperature CHT n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition 2;

[0059] Then perform the following steps: if ZRBZ_Sign_CHT_n is currently 0, set it to 1, and set CHT_Ovr_cnt_n to 1;

[0060] If ZRBZ_Sign_CHT_n is currently 1, then CHT_Ovr_cnt_n is incremented by 1;

[0061] If the current cylinder head temperature CHT n Cannot meet the cylinder head temperature CHT at the same time n Curve judgment condition 1 and CHT n Curve judgment condition 2;

[0062] Then set ZRBZ_Sign_CHT_n to 0, check if EGT_Ovr_cnt_n is greater than or equal to 6, and CHT is greater than n If it is greater than or equal to 45° and CHT_Ovr_cnt_n is greater than or equal to 5, it is determined that there is pre-ignition knock in cylinder n at the time of the current data row;

[0063] If the exhaust gas temperature EGT n The exhaust gas temperature EGT is not currently met n Curve judgment condition 1, but CHT_Ovr_cnt_n is greater than or equal to 6, and EGT_Ovr_cnt_n is greater than or equal to 6 at the same time, it is determined that there is pre-ignition knock in cylinder n at the current data row moment.

[0064] A device for detecting early combustion and knock of an aircraft engine, comprising:

[0065] The first setting module is configured to set the slope calculation time range of the exhaust temperature EGT to S_Cnt, with a typical value of 7, in seconds, to establish an engine exhaust temperature EGT slope calculation one-dimensional array EGT_KCalc_Arr, the size of which is S_Cnt*7, and to establish an engine cylinder head temperature CHT slope calculation one-dimensional array CHT_KCalc_Arr, the size of which is S_Cnt*7;

[0066] The second setting module is configured to set the row number of the currently read engine data as lineNum, and each time a row of engine data is read, lineNum is increased by 1, and the exhaust temperature of cylinders 1 to 6 in each row of engine data is set to EGT1 to EGT6, and the cylinder head temperature of cylinders 1 to 6 is set to CHT1 to CHT6;

[0067] The first calculation module is configured to calculate the exhaust gas temperature EGT "mainstream value" of the six cylinders in each row of engine data, the cylinder head temperature CHT "mainstream value" of the six cylinders, and the cylinder head temperature CHT of the six cylinders at the current time t. t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at the current time t minus 6 seconds (t-6)_n The "mainstream value" of the angle between the straight line formed by the two points and the horizontal line;

[0068] The second calculation module is configured to use the least square method to perform a straight line fitting on the exhaust temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second for any cylinder number n, and obtain the slopes of the fitting straight lines as K_EGT_n and K_CHT_n respectively;

[0069] The third setting module is configured to set the n cylinder exhaust temperature EGT early combustion knock start diagnosis flag to ZRBZ_Sign_EGT_n, the default value is 0, set the n cylinder exhaust temperature EGT early combustion knock diagnosis internal count to EGT_Ovr_cnt_n, the default value is 0; set the exhaust temperature EGT n Curve judgment condition 1;

[0070] The judgment module is configured to determine the exhaust gas temperature EGT n Comply with exhaust gas temperature EGT n When the curve judgment condition is 1 and the current value of ZRBZ_Sign_EGT_n is 1, the cylinder head temperature CHT is set n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition two, by judging whether the condition is met, it is determined whether there is pre-ignition knock in cylinder n at the moment of the current data row.

[0071] A system for detecting early combustion and knock of an aircraft engine comprises at least a memory and a processor. The memory stores a computer program. The processor implements the steps of a method for detecting early combustion and knock of an aircraft engine when executing the computer program on the memory.

[0072] An electronic device comprises a computer program. When the computer program is executed by a processor, the method for detecting early combustion and knock of an aircraft engine is implemented.

[0073] The present invention discloses an engine exhaust gas temperature (EGT) and cylinder head temperature (CHT) data recorded by an SD data card in a G1000 system of an SR20 aircraft. Any other recorded data that can provide engine exhaust temperature and cylinder head temperature in seconds can be detected using the method disclosed in the present invention. For example, if the engine is not installed on an aircraft but is tested on a test bench after overhaul, but the test bench can record the cylinder head temperature CHT and exhaust temperature EGT in seconds, the method can also be used for detection. The detection method is fast and accurate, and can greatly improve the accuracy and efficiency of TCM IO360ES's early combustion and knock detection, and can effectively avoid missed diagnosis caused by knowledge differences between aircraft maintenance personnel and avoid aircraft that have experienced early combustion and knock from taking to the sky without processing hidden dangers, thereby effectively ensuring aviation safety.

[0074] Reference Figure 2 and Figure 3 As shown in the figure, 8 exhaust temperature EGT and cylinder head temperature CHT curves of premature combustion and knock are randomly selected from the TCM IO360ES engine operating fleet. These 8 groups of curves cover the basic characteristics of premature combustion and knock curves of the TCM IO360ES engine. In each sub-graph, the upper curve cluster is the exhaust temperature EGT curve cluster of the 6 cylinders of the engine, and the lower curve cluster is the cylinder head temperature CHT curve cluster of the 6 cylinders of the engine. The cylinder curve characteristics of premature combustion and knock observed and counted are:

[0075] 1. Compared with the exhaust temperature EGT curve, the cylinder head temperature CHT curve is smoother, that is, the instantaneous change value is smaller. This is because the cylinder head temperature CHT sensor of the cylinder head is installed outside the cylinder head. The heat change generated by the combustion inside the engine takes a certain amount of time to be transmitted to the outside of the cylinder head, making the CHT curve show a greater "thermal inertia" than the exhaust temperature EGT curve. The exhaust temperature EGT sensor is installed on the exhaust pipe not far from the exhaust valve of each cylinder. It senses the combustion exhaust gas in the cylinder. The combustion exhaust gas in the cylinder can quickly reflect the heat change after the engine combustion, so the exhaust temperature EGT curve shows a smaller "thermal inertia".

[0076] 2. The exhaust temperature EGT or cylinder head temperature CHT curve of the cylinder with pre-ignition knock always deviates from the "mainstream curve" with a relatively high slope or a relatively large angle. After the pre-ignition knock ends, the cylinder head temperature CHT curve will fall back into the "mainstream curve" range. However, because the thermal inertia of the exhaust temperature EGT curve is small and the thermal inertia of the cylinder head temperature CHT curve is large, when pre-ignition knock occurs in a cylinder, the exhaust temperature EGT curve always deviates from the cylinder's mainstream exhaust temperature EGT curve first, and the cylinder head temperature CHT curve deviates later.

[0077] 3. The timing of the exhaust temperature EGT curve "returning to the mainstream curve" when pre-ignition knock occurs is relatively random. The main reason is that it is affected by the pilot's throttle operation. When pre-ignition knock occurs, the exhaust temperature EGT and the cylinder head temperature CHT on the cockpit instruments will rise relatively quickly. In order to avoid the rapid rise of the exhaust temperature EGT and the cylinder head temperature CHT, the pilot may retract the power lever to reduce the engine power. When the pilot retracts the power lever quickly, the exhaust temperature EGT curve will quickly fall back due to the small "thermal inertia". It is manifested as the exhaust temperature EGT curve falling with a large negative slope or even almost a straight line. However, due to the large "thermal inertia" of the cylinder head temperature CHT curve, it will not show a rapid linear decline similar to the exhaust temperature EGT, but after reaching a certain cylinder head temperature CHT peak, it will show a curve that is almost symmetrical with the rising stage of the cylinder head temperature CHT. If the pilot does not retract and reduce the engine power in time when the pre-ignition knock occurs, the exhaust temperature EGT curve and the cylinder head temperature CHT curve will reach a certain peak, and then the exhaust temperature EGT and the cylinder head temperature CHT will drop symmetrically during the rising stage. Another reason for the random drop of the exhaust temperature EGT is that the pre-ignition knock of a cylinder may have "intermittent occurrence" in a relatively short period of time, that is, in a relatively short period of time, the pre-ignition knock occurs when the physical condition of the cylinder is poor, and the cylinder burns normally when the physical condition of the cylinder is good. This kind of early combustion knock and normal combustion will also make the exhaust temperature EGT curve show the random characteristics of rising and falling.

[0078] 4. Although the drop of exhaust temperature EGT is random, when pre-ignition knock occurs, exhaust temperature EGT always leaves the mainstream curve before cylinder head temperature CHT, and can always maintain a rapid synchronous rising period with the cylinder head temperature CHT curve for a certain period of time before it drops back. This makes it feasible to use data analysis methods to diagnose pre-ignition knock of the TCM IO360ES engine. The present invention mainly uses the characteristics of the exhaust temperature EGT and cylinder head temperature CHT curves of the TCM IO360ES engine to detect pre-ignition knock faults.

[0079] The above embodiments are only used to explain the technical solutions of the present invention rather than to limit them. Those skilled in the art should understand that any modification and equivalent substitution that does not depart from the spirit and scope of the present invention should fall within the protection scope of the claims of the present invention.

Claims

1. A method for detecting early combustion and knock of an aircraft engine, characterized in that: include: S1, set the slope calculation time range of exhaust temperature EGT to S_Cnt, the typical value is 7, the unit is seconds, establish an engine exhaust temperature EGT slope calculation one-dimensional array EGT_KCalc_Arr, the size of the array is S_Cnt*7, establish an engine cylinder head temperature CHT slope calculation one-dimensional array CHT_KCalc_Arr, the size of the array is S_Cnt*7; S2, setting the row number of the currently read engine data as lineNum, and increasing lineNum by 1 for each row of engine data, and setting the exhaust temperatures of cylinders 1 to 6 in each row of engine data as EGT1 to EGT6, and the cylinder head temperatures of cylinders 1 to 6 as CHT1 to CHT6; S3, calculate the exhaust gas temperature EGT "mainstream value" of the six cylinders in each row of engine data, the cylinder head temperature CHT "mainstream value" of the six cylinders, and the cylinder head temperature CHT of the six cylinders at the current time t t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at the current time t minus 6 seconds (t-6)_n The "mainstream value" of the angle between the straight line formed by the two points and the horizontal line; S4, for any cylinder number n, use the least square method to perform straight line fitting on the exhaust temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second, and calculate the slopes of the fitting lines to be K_EGT_n and K_CHT_n respectively; S5, set the n cylinder exhaust temperature EGT early combustion knock start diagnosis flag to ZRBZ_Sign_EGT_n, the default value is 0, set the n cylinder exhaust temperature EGT early combustion knock diagnosis internal count to EGT_Ovr_cnt_n, the default value is 0; set the exhaust temperature EGT n Curve judgment condition 1; S6, at exhaust gas temperature EGT n Comply with exhaust gas temperature EGT n When the curve judgment condition is 1 and the current value of ZRBZ_Sign_EGT_n is 1, the cylinder head temperature CHT is set n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition two, by judging whether the condition is met, it is determined whether there is pre-ignition knock in cylinder n at the moment of the current data row.

2. The method for detecting aircraft engine pre-ignition knock according to claim 1, characterized in that: In step S2, the row number of the currently read engine data is set as lineNum, and each time a row of engine data is read, lineNum is increased by 1, and the exhaust temperatures of cylinders 1 to 6 in each row of engine data are set as EGT1 to EGT6, and the cylinder head temperatures of cylinders 1 to 6 are set as CHT1 to CHT6, wherein the following is also included: Assume that the latest data storage index of the exhaust temperature EGT slope calculation one-dimensional array is Index1, and Index1 is equal to the remainder of lineNum divided by S_Cnt; Assume that the oldest data storage index of the exhaust temperature EGT slope calculation one-dimensional array is Index2, and Index2 is equal to the remainder of Index1 plus 1 divided by S_Cnt; Each time a row of engine data is read, the exhaust temperature EGT of cylinder n (0≤n≤6) is calculated. n Put it into the EGT_KCalc_Arr array [S_Cnt*(n-1)+Index1] index position, and put the cylinder head temperature CHT of cylinder n (0≤n≤6) n Put it into the CHT_KCalc_Arr array at the index position [S_Cnt*(n-1)+Index1].

3. The method for detecting aircraft engine pre-ignition knock according to claim 1, characterized in that: In step S3, the cylinder head temperatures CHT of the six cylinders at the current time t are calculated. t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at the current time t minus 6 seconds (t-6)_n The angle between the straight line formed by the two points and the horizontal line, wherein the angle is calculated by arctan{[(CHT t_n -CHT (t-6)_n ) / 6]}*180 / π.

4. The method for detecting aircraft engine pre-ignition knock according to claim 1, characterized in that: In step S3, it also includes: Set the exhaust temperature EGT "mainstream value" of the 6 cylinders to IntensiveEGT and put it into the index position of the EGT_KCalc_Arr array (S_Cnt*6+Index1); Put the "mainstream value" of the cylinder head temperature CHT of the 6 cylinders into the index position of the CHT_KCalc_Arr array [S_Cnt*6+Index1].

5. The method for detecting aircraft engine pre-ignition knock according to claim 1, characterized in that: In the step S4, it also includes: In the EGT_KCalc_Arr and CHT_KCalc_Arr arrays, for the "mainstream values" of the exhaust temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second, the "standard slopes" stdK_EGT and stdK_CHT of the "mainstream values" of the exhaust temperature EGT and the cylinder head temperature CHT in the fitting straight line are calculated by the least square method respectively; Calculate the angle EGTJiajiao between the slope of the fitted straight line K_EGT_n and the standard slope stdK_EGT of the exhaust temperature of cylinder n n =arctan[(K_EGT_n-stdK_EGT) / (1+K_EGT_n*stdK_EGT)]; Calculate the angle CHTjiaodu between the fitted straight line and the horizontal line of the cylinder head temperature of cylinder n n =arctan(K_CHT_n) and the angle between the mainstream fitting straight line of the cylinder head temperature and the horizontal line std_CHTjiaodu=arctan(stdK_CHT).

6. The method for detecting aircraft engine pre-ignition knock according to claim 1, characterized in that: In step S5, it also includes: Set exhaust gas temperature EGT n Curve judgment condition 1: K_EGT_n is greater than stdK_EGT and K_EGT_n is greater than 0.81 and EGT is equal to n Greater than or equal to 40°, or the current value of ZRBZ_Sign_EGT_n is 1 and the row number of the data row where the current diagnosis is located is less than 150 from the row number of the row where ZRBZ_Sign_EGT_n was last changed from 0 to 1, that is, no more than 150 seconds, and the exhaust temperature of the current cylinder n is higher than or equal to the exhaust temperature "mainstream value" by more than 50 degrees Fahrenheit, and when K_EGT_n is less than or equal to 0, that is, the exhaust temperature EGT curve falls back, the exhaust temperature EGT pre-ignition knock diagnosis internal count EGT_Ovr_cnt_n is still less than 6; If the exhaust gas temperature EGT n The current curve corresponds to the exhaust gas temperature EGT n Curve judgment condition 1: If the current value of ZRBZ_Sign_EGT_n is 0, then set ZRBZ_Sign_EGT_n to 1. n When it is greater than or equal to 40°, EGT_Ovr_cnt_n increases by 1. If EGTJiajiao n If it is less than 40° and EGT_Ovr_cnt_n is less than 6 at the same time, set EGT_Ovr_cnt_n to 0 and restart counting.

7. The method for detecting aircraft engine pre-ignition knock according to claim 6, characterized in that: In step S6, it also includes: Set the cylinder head temperature CHT n Curve judgment condition 1: CHTjiaodu n Greater than or equal to 20° and CHTjiaodu n Subtract std_CHTjiaodu greater than or equal to 20°; Set the cylinder head temperature CHT n Curve judgment condition 2: CHTjiaodu at the current moment n Subtract CHTjiaodu from the previous second n_(t-1) Greater than or equal to -2°, that is, the cylinder head temperature CHT rises and does not fall back. If it falls back, the rate of fall is no more than 2 degrees Fahrenheit / second; Set the cylinder head temperature CHT curve early combustion knock start diagnosis flag ZRBZ_Sign_CHT_n of the cylinder, the default value is 0, set the exhaust temperature EGT early combustion knock diagnosis internal count to CHT_Ovr_cnt_n, the default value is 0; If the current cylinder head temperature CHT n At the same time, the cylinder head temperature CHT n Curve judgment condition 1 and CHT n Curve judgment condition 2; Then perform the following steps: if ZRBZ_Sign_CHT_n is currently 0, set it to 1, and set CHT_Ovr_cnt_n to 1; If ZRBZ_Sign_CHT_n is currently 1, then CHT_Ovr_cnt_n is incremented by 1; If the current cylinder head temperature CHT n Cannot meet the cylinder head temperature CHT at the same time n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition 2; Then set ZRBZ_Sign_CHT_n to 0, check if EGT_Ovr_cnt_n is greater than or equal to 6, and CHT is greater than n If it is greater than or equal to 45° and CHT_Ovr_cnt_n is greater than or equal to 5, it is determined that there is pre-ignition knock in cylinder n at the time of the current data row; If the exhaust gas temperature EGT n The exhaust gas temperature EGT is not currently met n Curve judgment condition 1, but CHT_Ovr_cnt_n is greater than or equal to 6, and EGT_Ovr_cnt_n is greater than or equal to 6 at the same time, it is determined that there is pre-ignition knock in cylinder n at the current data row moment.

8. A device for detecting premature combustion and knock of an aircraft engine, characterized in that: include: The first setting module is configured to set the slope calculation time range of the exhaust temperature EGT to S_Cnt, with a typical value of 7, in seconds, to establish an engine exhaust temperature EGT slope calculation one-dimensional array EGT_KCalc_Arr, the size of which is S_Cnt*7, and to establish an engine cylinder head temperature CHT slope calculation one-dimensional array CHT_KCalc_Arr, the size of which is S_Cnt*7; The second setting module is configured to set the row number of the currently read engine data as lineNum, and each time a row of engine data is read, lineNum is increased by 1, and the exhaust temperature of cylinders 1 to 6 in each row of engine data is set to EGT1 to EGT6, and the cylinder head temperature of cylinders 1 to 6 is set to CHT1 to CHT6; The first calculation module is configured to calculate the exhaust gas temperature EGT "mainstream value" of the six cylinders in each row of engine data, the cylinder head temperature CHT "mainstream value" of the six cylinders, and the cylinder head temperature CHT of the six cylinders at the current time t. t_n (0≤n≤6, n represents the cylinder number) and the cylinder head temperature CHT at the current time t minus 6 seconds (t-6)_n The "mainstream value" of the angle between the straight line formed by the two points and the horizontal line; The second calculation module is configured to use the least square method to perform a straight line fitting on the exhaust temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second for any cylinder number n, and obtain the slopes of the fitting straight lines as K_EGT_n and K_CHT_n respectively; The third setting module is configured to set the n cylinder exhaust temperature EGT early combustion knock start diagnosis flag to ZRBZ_Sign_EGT_n, the default value is 0, set the n cylinder exhaust temperature EGT early combustion knock diagnosis internal count to EGT_Ovr_cnt_n, the default value is 0; set the exhaust temperature EGT n Curve judgment condition 1; The judging module is configured to n Comply with exhaust gas temperature EGT n When the curve judgment condition is 1 and the current value of ZRBZ_Sign_EGT_n is 1, the cylinder head temperature CHT is set n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition two, by judging whether the condition is met, it is determined whether there is pre-ignition knock in cylinder n at the moment of the current data row.

9. A system for detecting early combustion and knock of an aircraft engine, characterized in that: The method comprises at least a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of a method for detecting pre-ignition and knock of an aircraft engine as described in any one of claims 1 to 7 when executing the computer program on the memory.

10. An electronic device comprising a computer program, characterized in that When the computer program is executed by a processor, a method for detecting aircraft engine pre-ignition knock as described in any one of claims 1 to 7 is implemented.

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