Method, device, system and equipment for detecting pre-ignition knock of an aircraft engine

Abstract

The present invention provides a method, device, system, and apparatus for detecting pre-ignition knock in an aircraft engine. The method includes the following steps: S1, setting the exhaust gas temperature (EGT) slope calculation time range to S_Cnt, typically 7 seconds, establishing a one-dimensional array for calculating the engine exhaust gas temperature (EGT) slope to EGT_KCalc_Arr, the size of which is S_Cnt*7, and establishing a one-dimensional array for calculating the engine cylinder head temperature (CHT) slope to CHT_KCalc_Arr, the size of which is S_Cnt*7; and S2, setting the row number of the currently read engine data to lineNum, incrementing lineNum by 1 for each row of engine data read, setting the exhaust temperatures of cylinders 1 to 6 in each row of engine data to EGT1 to EGT6, and setting the cylinder head temperatures of cylinders 1 to 6 to CHT1 to CHT6. The present invention improves the accuracy and efficiency of aircraft engine pre-ignition and detonation detection, effectively avoids missed diagnosis caused by knowledge differences among aircraft maintenance personnel and avoids hidden dangers of untreated aircraft that have experienced pre-ignition and detonation, thereby effectively ensuring aviation safety.

Description

Technical Field

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

[0002] The SR20, manufactured by the American company Cirrus Design, is known as the "BMW of the Sky." Its all-composite structure and integrated parachute system provide exceptional flight performance and safety, making it widely used for private flight and flight training. Cirrus' SR series aircraft boast over 6,000 aircraft worldwide. The Cirrus SR20 is equipped with a TCM IO360ES six-cylinder aircraft piston engine. Due to design flaws, this engine is more susceptible to pre-ignition detonation (PDD) than Lycoming engines. Despite numerous design improvements and component upgrades, the manufacturer has yet to fundamentally address this vulnerability. PDD is an abnormal, explosive combustion event that, depending on its severity and duration, can cause irreversible damage to the engine. If not promptly detected and repaired, an aircraft experiencing PDD will remain in service with this potential risk. As the damage progresses, the aircraft could experience an in-flight engine failure, resulting in fatalities. Summary of the Invention

[0003] The purpose of the present invention is to provide a method, device, system and equipment for detecting pre-ignition 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] A first aspect of the present invention provides a method for detecting pre-ignition knock in an aircraft engine, comprising:

[0007] S1. Set the exhaust gas temperature (EGT) slope calculation time range to S_Cnt, typically 7 seconds. Create a one-dimensional array for calculating the engine exhaust gas temperature (EGT) slope, EGT_KCalc_Arr, with a size of S_Cnt*7. Create a one-dimensional array for calculating the engine cylinder head temperature (CHT) slope, CHT_KCalc_Arr, with a size of S_Cnt*7.

[0008] S2, set the row number of the currently read engine data as lineNum, and increment lineNum by 1 for each row of engine data. Set the exhaust temperatures of cylinders 1 to 6 in each row of engine data to EGT1 to EGT6, and the cylinder head temperatures of cylinders 1 to 6 to 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 squares method to perform a straight line fit on the exhaust gas temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second. Calculate the slopes of the fitted lines as K_EGT_n and K_CHT_n, respectively.

[0011] S5, set the n cylinder exhaust temperature EGT early combustion knock diagnosis start 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 2: 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 pre-ignition knock in an aircraft engine, comprising:

[0014] The first setting module is configured to set the exhaust gas temperature (EGT) slope calculation time range to S_Cnt, with a typical value of 7, in seconds, to establish an engine exhaust gas 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 incremented 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;

[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 squares method to perform a straight line fit on the exhaust gas 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 calculate the slopes of the fitted 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 2: 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 disclosed in the present invention provides a system for detecting pre-ignition knock in an aircraft engine, which includes at least a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps of the method for detecting pre-ignition knock in an aircraft engine when executing the computer program on the memory.

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

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

[0023] The present invention discloses a method for detecting exhaust gas temperature (EGT) and cylinder head temperature (CHT) data recorded by an SD data card within the G1000 system of an SR20 aircraft. Any other data that can provide engine exhaust gas temperature and cylinder head temperature records in seconds can be detected using the method disclosed in the present invention. For example, if an engine is not installed on an aircraft but is instead tested on a test bench after refurbishment, but the test bench is capable of recording CHT and exhaust gas temperature (EGT) in seconds, this method can also be used for detection. This detection method is rapid and accurate, and can greatly improve the accuracy and efficiency of pre-ignition knock detection in the TCM IO360ES. It can effectively avoid missed diagnoses caused by knowledge differences among aircraft maintenance personnel and prevent aircraft that have experienced pre-ignition knock from taking to the air without addressing potential risks, thereby effectively ensuring aviation safety. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0026] Figure 3 This 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 invention claimed for protection, but merely represents 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 to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0029] Reference Figures 1 to 3 As shown, a method for detecting pre-ignition knock in an aircraft engine includes:

[0030] S1. Set the exhaust gas temperature (EGT) slope calculation time range to S_Cnt, typically 7 seconds. Create a one-dimensional array for calculating the engine exhaust gas temperature (EGT) slope, EGT_KCalc_Arr, with a size of S_Cnt*7. Create a one-dimensional array for calculating the engine cylinder head temperature (CHT) slope, CHT_KCalc_Arr, with a size of S_Cnt*7.

[0031] S2, set the row number of the currently read engine data as lineNum, and increment lineNum by 1 for each row of engine data. Set the exhaust temperatures of cylinders 1 to 6 in each row of engine data to EGT1 to EGT6, and the cylinder head temperatures of cylinders 1 to 6 to 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 squares method to perform a straight line fit on the exhaust gas temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second. Calculate the slopes of the fitted lines as K_EGT_n and K_CHT_n, respectively.

[0034] S5, set the n cylinder exhaust temperature EGT early combustion knock diagnosis start 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 2: 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. Each time a row of engine data is read, lineNum is incremented by 1. 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. The following also includes:

[0037] Assume that the latest data of the exhaust gas temperature (EGT) slope calculation one-dimensional array is stored at index 1, and Index 1 is equal to the remainder of dividing lineNum by S_Cnt.

[0038] Assume that the oldest data in the one-dimensional array for calculating the exhaust gas temperature (EGT) slope is stored at index 2, and that Index 2 is equal to the remainder of Index 1 plus 1 divided by S_Cnt.

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

[0040] In step S3, the cylinder head temperatures CHT of the six cylinders at the current time t are 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" reflect the mainstream levels of exhaust temperature and cylinder head temperature, as well as the "instantaneous changes in the exhaust temperature curve," in each line of engine data. They serve as the benchmark 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 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 gas temperature EGT "mainstream value" of the six 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 further includes:

[0048] In the EGT_KCalc_Arr and CHT_KCalc_Arr arrays, the "mainstream values" of the exhaust temperature EGT and cylinder head temperature CHT from the current time t to t-S_Cnt+1 second are respectively calculated using the least squares method to calculate the "standard slopes" stdK_EGT and stdK_CHT of the "mainstream values" of the exhaust temperature EGT and cylinder head temperature CHT in the fitting lines. The virtual curve formed by the mainstream values ​​of EGT and cylinder head temperature CHT is the "mainstream curve" calculated in step S3. Pre-ignition knock is detected by comparing the difference or change between the actual curve of the exhaust temperature EGT or 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 cylinder head temperature mainstream value fitting straight line 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 Jiajiao n Greater than or equal to 40°, or the current value of ZRBZ_Sign_EGT_n is 1 and the row number of the current diagnosis data row is less than 150 from the row number of the row where ZRBZ_Sign_EGT_n last changed from 0 to 1, that is, no more than 150 seconds, and the current exhaust temperature of cylinder n is more than 50 degrees Fahrenheit higher than the exhaust temperature "mainstream value", and when K_EGT_n is less than or equal to 0, that is, the exhaust temperature EGT curve shows a decline, 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 is consistent with 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. If EGT Jiajiao n When it is greater than or equal to 40°, EGT_Ovr_cnt_n increases by 1. If EGT Jiajiao n If the angle is less than 40° and EGT_Ovr_cnt_n is less than 6, set EGT_Ovr_cnt_n to 0 and restart counting.

[0054] In step S6, it also includes:

[0055] Set 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 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 add 1 to CHT_Ovr_cnt_n;

[0061] If the current cylinder head temperature CHT n Unable to simultaneously meet the cylinder head temperature CHT 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 CHTjiaodu n If the angle is greater than or equal to 45° and CHT_Ovr_cnt_n is greater than or equal to 5, it is determined that pre-ignition knock exists 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 also greater than or equal to 6, then it is determined that pre-ignition knock exists in cylinder n at the current data row moment.

[0064] A device for detecting pre-ignition knock of an aircraft engine, comprising:

[0065] The first setting module is configured to set the exhaust gas temperature (EGT) slope calculation time range to S_Cnt, with a typical value of 7, in seconds, to establish an engine exhaust gas 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 incremented 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;

[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 squares method to perform a straight line fit on the exhaust gas 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 calculate the slopes of the fitted 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 2: 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 pre-ignition knock in 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 pre-ignition knock in an aircraft engine when executing the computer program in the memory.

[0072] An electronic device includes a computer program. When the computer program is executed by a processor, the method for detecting pre-ignition knock of an aircraft engine is implemented.

[0073] The present invention discloses a method for recording engine exhaust gas temperature (EGT) and cylinder head temperature (CHT) data using an SD data card within the G1000 system of an SR20 aircraft. Any other recorded data capable of providing engine exhaust gas temperature and cylinder head temperature in seconds can be detected using the method disclosed in the present invention. For example, if an engine is not installed on an aircraft but is instead tested on a test bench after refurbishment, but the test bench is capable of recording cylinder head temperature CHT and exhaust gas temperature EGT in seconds, this method can also be used for detection. This detection method is rapid and accurate, greatly improving the accuracy and efficiency of pre-ignition knock detection in the TCM IO360ES. It can effectively avoid missed diagnoses caused by knowledge differences among aircraft maintenance personnel and prevent aircraft that have experienced pre-ignition knock from taking to the air without addressing potential risks, thereby effectively ensuring aviation safety.

[0074] Reference Figure 2 and Figure 3 As shown, eight randomly selected exhaust gas temperature (EGT) and cylinder head temperature (CHT) curves for pre-ignition knock are plotted from the TCM IO360ES engine fleet. These eight curves represent the basic characteristics of pre-ignition knock in the TCM IO360ES engine. In each sub-graph, the upper cluster of curves represents the exhaust gas temperature (EGT) curves for the six cylinders of the engine, while the lower cluster represents the cylinder head temperature (CHT) curves for the six cylinders of the engine. The observed and statistically analyzed cylinder curve characteristics of pre-ignition knock are:

[0075] 1. The cylinder head temperature (CHT) curve is smoother than the exhaust gas temperature (EGT) curve, meaning that instantaneous fluctuations are smaller. This is because the cylinder head temperature (CHT) sensor is mounted externally. Heat changes generated by internal engine combustion take time to transmit to the outside of the cylinder head, causing the CHT curve to exhibit greater "thermal inertia" than the exhaust gas temperature (EGT) curve. The exhaust gas temperature (EGT) sensor, on the other hand, is mounted on the exhaust pipe near each cylinder's exhaust valve. It senses the exhaust gases within the cylinder, which can quickly reflect heat changes after combustion. Therefore, the exhaust gas temperature (EGT) curve exhibits less thermal inertia.

[0076] 2. The exhaust gas temperature (EGT) or cylinder head temperature (CHT) curves of cylinders experiencing pre-ignition knock often deviate significantly from the "mainstream" curve with a relatively high slope or angle. After the pre-ignition knock subsides, the cylinder head temperature (CHT) curve returns to the "mainstream" curve range. However, because the thermal inertia of the exhaust gas temperature (EGT) curve is low, while the thermal inertia of the cylinder head temperature (CHT) curve is high, when pre-ignition knock occurs in a cylinder, the exhaust gas temperature (EGT) curve always deviates from the cylinder's mainstream EGT curve first, followed by the cylinder head temperature (CHT) curve.

[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 the influence of the pilot's throttle control. When pre-ignition knock occurs, the exhaust temperature EGT and cylinder head temperature CHT on the cockpit instruments will show a relatively rapid rise. In order to avoid the rapid rise of exhaust temperature EGT and cylinder head temperature CHT, the pilot may retract the power lever to reduce engine power. When the pilot retracts the power lever quickly, the exhaust temperature EGT curve will quickly fall back due to its small "thermal inertia". This is manifested as the exhaust temperature EGT curve falling with a large negative slope or even almost a straight line. However, due to its large "thermal inertia", the cylinder head temperature CHT curve will not show a rapid linear decline similar to the exhaust temperature EGT. Instead, 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 fails to reduce engine power in a timely manner when pre-ignition knock occurs, the exhaust gas temperature (EGT) and cylinder head temperature (CHT) curves will each reach a peak before experiencing a symmetrical decline in the EGT and CHT curves during their respective rising phases. Another reason for the random nature of EGT declines is that pre-ignition knock in a cylinder can be intermittent within a short period of time. This means that within a short period of time, pre-ignition knock may occur when the cylinder's physical conditions are poor, while normal combustion occurs when the cylinder's physical conditions are good. This alternating pattern of pre-ignition knock and normal combustion can also cause the EGT curve to exhibit a random pattern of rises and falls.

[0078] 4. Although the drop in exhaust gas temperature (EGT) is random, when pre-ignition knock occurs, the exhaust gas temperature (EGT) always deviates from the mainstream curve before the cylinder head temperature (CHT). Before it drops back, it always maintains a rapid synchronous rise period with the cylinder head temperature (CHT) curve for a certain period of time. This makes it feasible to use data analysis methods to diagnose pre-ignition knock in the TCM IO360ES engine. The present invention primarily uses the characteristics of the exhaust gas 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 illustrate the technical solutions of the present invention and are not intended to limit the present invention. Those skilled in the art should understand that any modifications and equivalent substitutions that do not depart from the spirit and scope of the present invention should fall within the scope of protection of the claims of the present invention.

Claims

1. A method for detecting pre-ignition knock in an aircraft engine, characterized in that: include: S1. Set the exhaust gas temperature (EGT) slope calculation time range to S_Cnt, typically 7 seconds. Create a one-dimensional array for calculating the engine exhaust gas temperature (EGT) slope, EGT_KCalc_Arr, with a size of S_Cnt*7. Create a one-dimensional array for calculating the engine cylinder head temperature (CHT) slope, CHT_KCalc_Arr, with a size of S_Cnt*7. S2, set the row number of the currently read engine data as lineNum, and increment lineNum by 1 for each row of engine data. Set the exhaust temperatures of cylinders 1 to 6 in each row of engine data to EGT1 to EGT6, and the cylinder head temperatures of cylinders 1 to 6 to 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 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; Among them, 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 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 are divided into 15 groups, and 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 minimum value is selected. The average of the four values ​​in this group is the "mainstream value"; S4. For any cylinder number n, use the least squares method to perform a straight line fit on the exhaust gas temperature EGT and the cylinder head temperature CHT from the current time t to t-S_Cnt+1 second. Calculate the slopes of the fitted lines as K_EGT_n and K_CHT_n, respectively. S5, set the n cylinder exhaust temperature EGT early combustion knock diagnosis start 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, set the cylinder head temperature CHT n Curve judgment condition 1 and cylinder head temperature CHT n Curve judgment condition 2: By judging whether the condition is met, it is determined whether there is pre-ignition knock in cylinder n at the time of the current data row; In step S6, it also includes: Set 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 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 add 1 to CHT_Ovr_cnt_n; If the current cylinder head temperature CHT n Unable to simultaneously meet the cylinder head temperature CHT 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 CHTjiaodu n If the angle is greater than or equal to 45° and CHT_Ovr_cnt_n is greater than or equal to 5, it is determined that pre-ignition knock exists 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 also greater than or equal to 6, then it is determined that pre-ignition knock exists in cylinder n at the current data row moment.

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. Each time a row of engine data is read, lineNum is incremented by 1. 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. The following also includes: Assume that the latest data of the exhaust gas temperature (EGT) slope calculation one-dimensional array is stored at index 1, and Index 1 is equal to the remainder of dividing lineNum by S_Cnt. Assume that the oldest data in the one-dimensional array for calculating the exhaust gas temperature (EGT) slope is stored at index 2, and that Index 2 is equal to the remainder of Index 1 plus 1 divided by S_Cnt. Each time a line of engine data is read, the exhaust gas temperature EGT of cylinder n is converted to 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 n Put it into the CHT_KCalc_Arr array at the index [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 t_n 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 gas temperature EGT "mainstream value" of the six cylinders to IntensiveEGT and put it into the EGT_KCalc_Arr array [S_Cnt*6+Index1] index position; 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 further includes: In the EGT_KCalc_Arr and CHT_KCalc_Arr arrays, for the "mainstream values" of exhaust temperature EGT and 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 exhaust temperature EGT and cylinder head temperature CHT in the fitted lines are calculated using the least squares method. 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 cylinder head temperature mainstream value fitting straight line 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 Jiajiao n Greater than or equal to 40°, or the current value of ZRBZ_Sign_EGT_n is 1 and the row number of the current diagnosis data row is less than 150 from the row number of the row where ZRBZ_Sign_EGT_n last changed from 0 to 1, that is, no more than 150 seconds, and the current exhaust temperature of cylinder n is more than 50 degrees Fahrenheit higher than the exhaust temperature "mainstream value", and when K_EGT_n is less than or equal to 0, that is, the exhaust temperature EGT curve shows a decline, the exhaust temperature EGT pre-ignition knock diagnosis internal counter EGT_Ovr_cnt_n is still less than 6; If the exhaust gas temperature EGT n The current curve is consistent with 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. If EGT Jiajiao n When it is greater than or equal to 40°, EGT_Ovr_cnt_n increases by 1. If EGT Jiajiao n If the angle is less than 40° and EGT_Ovr_cnt_n is less than 6, set EGT_Ovr_cnt_n to 0 and restart counting.

7. A device for detecting pre-ignition knock in an aircraft engine, characterized in that: include: The first setting module is configured to set the exhaust gas temperature (EGT) slope calculation time range to S_Cnt, with a typical value of 7, in seconds, to establish an engine exhaust gas 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 incremented 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; 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 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; Among them, 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 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 are divided into 15 groups, and 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 minimum value is selected. The average of the four values ​​in this group is the "mainstream value"; The second calculation module is configured to use the least squares method to perform a straight line fit on the exhaust gas 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 calculate the slopes of the fitted 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 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 2: 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.

8. A system for detecting pre-ignition knock in 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 the method for detecting pre-ignition knock of an aircraft engine as described in any one of claims 1 to 6 when executing the computer program on the memory.

9. An electronic device comprising a computer program, characterized in that When the computer program is executed by a processor, the method for detecting pre-ignition knock in an aircraft engine as claimed in any one of claims 1 to 6 is implemented.

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