A method for evaluating the performance of components of a TCM IO360ES engine fuel system

Abstract

The application discloses a kind of methods for evaluating TCM IO360ES engine fuel system component performance, first stage is carried out with the purpose of survival of the fittest engine driven fuel pump performance evaluation, second stage with the purpose of survival of the fittest engine throttle metering body performance evaluation, reach through in the aircraft operation engine test car when executing this evaluation method and judging threshold, can the core component performance of this type engine fuel system is threshold monitored, reach real-time tracking monitoring engine performance condition, early discovery fault trend, improve the purpose of engine operation reliability.The application can conveniently monitor the main pump reference operating point deviation, achieve real-time control of engine performance;Parameter setting has a basis to follow, troubleshooting and replacement spare parts have a clear target, the process is simple and effective, reduces the waste of manpower and material resources, and economic indicators are good.

Description

TECHNICAL FIELD

[0001] The application discloses a method for evaluating performance of a TCM IO360ES engine fuel system component, and belongs to the technical field of aircraft maintenance. BACKGROUND

[0002] The SR20 aircraft produced by Cirrus Design Company in the United States is called "air BMW", adopts a whole machine composite material structure and is equipped with a whole machine parachute system, has excellent flight quality and high safety, and has been widely applied in private use and flight training, and the SR series aircraft of Cirrus Company has more than 6000 aircraft in the world.

[0003] The Cirrus SR20 aircraft is configured with an IO360ES type aviation piston engine produced by the TCM company in the United States, and the engine automatic parking in the slow vehicle state is an inherent fault of the Cirrus SR20 aircraft. Although the SR series aircraft of Cirrus has more than 6000 aircraft in the world, the engine slow vehicle parking problem has not been effectively solved for many years. TCM is one of the two giants of aviation piston engines in the world, and its products are not only used in the Cirrus SR series aircraft, and the similar engine fuel injection systems are mostly used. However, the TCM company does not disclose the mechanism of the frequent slow vehicle parking fault of the engine in operation. There is no academic report on the elimination method of the slow vehicle parking fault of the engine using the TCM fuel injection system in the field of aviation maintenance engineering. Because the cause of the fault is unknown, the frequent engine slow vehicle parking fault in operation brings great psychological pressure to the pilots, and the maintenance technical personnel can only replace the fuel system related components of the fault engine, which brings great loss of manpower and material resources, and also brings great flight safety risk. In particular, the frequent engine "landing parking" in engineering practice, this engine slow vehicle parking fault occurs in the process of the aircraft just landing off the runway. Since the aircraft just lands, the engine stops, if the parking fault occurs a few minutes ago, the aircraft is still in the landing approach, which is a great safety threat to the single-engine aircraft, so this "landing parking" brings great psychological pressure to the pilots.

[0004] The slow vehicle parking of the TCM IO360ES engine is related to the drift of the reference working point parameters, and the drift of the reference working point parameters is related to the performance of the core components of the engine fuel system. There are two high-value core components in the engine fuel system, which play a decisive role in the comprehensive performance of the engine fuel system. One is the engine driven fuel pump for controlling the reference working point of the engine, and the other is the throttle metering body for controlling the power of the engine.

[0005] On this type of engine, the output oil pressure of the engine driven fuel pump at the rated slow speed (600 rpm) is the reference operating point of the engine, due to the structural design and performance characteristics of the engine driven fuel pump, its output pressure is easily affected, causing the engine reference operating point to deviate, resulting in engine slow speed parking difficult fault; And the throttle metering body has a throttle valve and corresponding fuel metering device, which can provide appropriate oil-gas ratio for the engine according to the opening of the throttle valve, and due to its structural design and performance characteristics, the oil-gas ratio will deviate, resulting in incorrect oil-gas ratio of the engine cylinder mixture, causing the engine to work abnormally.

[0006] Early combustion / knock and valve sticking are also typical difficult faults of TCM IO360ES engine in engineering practice. The performance drift of the throttle metering body causes the engine to run over lean oil at medium speed, which is one of the reasons for the frequent occurrence of early combustion / knock and valve sticking faults, so it is necessary to have a method that can evaluate the performance of the core components of the fuel system of this type of engine in engineering practice. The amount of this performance drift must be limited within a certain threshold range. SUMMARY

[0007] The present application provides a method for evaluating the performance of the fuel system components of TCM IO360ES engine, which can evaluate the performance of the core components of the fuel system of TCM IO360ES type aviation piston engine and determine the threshold value. The evaluation method and threshold value do not require the use of any professional equipment, and can be seamlessly integrated into the engine test program of this type of aircraft, and is easy for flight personnel and maintenance personnel to operate in engineering practice. Therefore, by performing the evaluation method and threshold value during engine test in aircraft operation, the performance of the core components of the fuel system of this type of engine can be monitored, and the purpose of real-time tracking and monitoring of engine performance, early detection of fault trend and improvement of engine operation reliability can be achieved.

[0008] In order to achieve the above technical purpose, a method for evaluating the performance of the fuel system components of TCM IO360ES engine, the specific process is as follows:

[0009] First stage: engine driven fuel pump performance evaluation for the purpose of survival of the fittest, the implementation steps are as follows:

[0010] Step 1: Start the engine to control the engine speed not more than 1200 rpm, and warm up the oil temperature to enter the green zone;

[0011] The oil temperature described in the present application is the lubricating oil temperature;

[0012] Step 2: Return the throttle to the slow speed position, record the engine slow speed fuel flow value under the normal running slow speed state of the engine, and set it as the first fuel flow F1;

[0013] Specifically, the normal running idle state refers to an engine idle speed of 800 ± 50 rpm ；

[0014] Step 3: Push the throttle to the maximum power position and turn on the electric fuel booster pump. After working at full throttle for 2-6 seconds, close the throttle, and turn off the electric fuel booster pump when the engine speed is about 1700 ± 150 rpm.

[0015] Step 4: Continue to close the throttle to the idle position, and record the engine fuel flow value again, set as the second fuel flow F2.

[0016] Step 5: Calculate the difference between the first fuel flow and the second fuel flow, set the difference as ΔF 12 ; the larger the difference, the worse the stability of the engine-driven fuel pump; if ΔF 12 > 0.2 gph, it is determined that the performance of the engine-driven fuel pump cannot meet the normal operation requirements, and the pump needs to be replaced.

[0017] Second stage: engine throttle metering performance evaluation for the purpose of survival of the fittest

[0018] Step 1: Start the engine and control the engine speed not to exceed 1200 rpm, and warm up the oil temperature to the green zone.

[0019] Step 2: Slowly push the throttle to stabilize the engine speed at 1700 ± 50 rpm. During this process, the throttle cannot be closed.

[0020] If the throttle is pushed too much, causing the engine speed to exceed 1700 rpm, then the throttle is closed to reduce the engine speed to below 1650 rpm, and then the engine speed is slowly pushed to stabilize at 1700 ± 50 rpm.

[0021] Step 3: Record the engine fuel flow value at this time, set as the third fuel flow F3.

[0022] Step 4: Continue to push the throttle to increase the engine speed to above 1800 rpm.

[0023] Step 5: Slowly close the throttle to reduce and stabilize the engine speed at 1700 rpm. During this process, the throttle cannot be pushed.

[0024] If the throttle is closed too much, causing the engine speed to be below 1700 rpm, then the 4th and 5th steps must be re-executed.

[0025] Step 6: Record the engine fuel flow value at this time, set as the fourth fuel flow F4.

[0026] Step 7: Calculate the difference between the third fuel flow F3 and the fourth fuel flow F4, and set the difference as ΔF 34 The greater the difference, the worse the stability of the fuel metering body; if ΔF 34 > 0.2 gph, it is determined that the performance of the fuel metering body cannot meet the normal operation requirements, and the fuel metering body needs to be replaced.

[0027] Due to the engine-driven fuel pump performance evaluation for the purpose of survival of the fittest, in the engine ground test, various use states of the engine-driven fuel pump in the actual operation of the aircraft are simulated, and the fuel flow drift is used as a quantitative index to measure the performance stability of the engine-driven fuel pump; due to the engine fuel metering body performance evaluation for the purpose of survival of the fittest, the fuel flow drift under the typical test speed state can be used as a quantitative index to measure the performance stability of the engine fuel metering body in the engine ground test. The combination of the two technical means achieves the purpose of real-time tracking and monitoring the performance of the engine, early detection of fault trends, and improvement of the reliability of the engine.

[0028] The theoretical basis of the method for evaluating the performance of the core components of the TCM IO360ES engine fuel system is:

[0029] A, engine-driven fuel pump performance drift mechanism

[0030] On the TCM IO360ES aviation piston engine, the output oil pressure of the engine-driven fuel pump at the rated slow-speed rotating speed (600 rpm) is the reference working point of the engine. According to the provisions of the technical manual of the engine, the output oil pressure at the reference working point should be 7-9 psiThe engine drives the fuel pump to provide suitable fuel pressure under different engine speed, the pump is composed of two parts, the supercharging unit and the control unit, the supercharging unit is a rotary plate pump, the control unit is composed of the main valve, the slow valve and the mixture ratio valve. Since the rotary plate pump is a constant volume pump, the fuel output is fixed per rotation, to ensure sufficient fuel supply, the rotary plate pump output is greater than the actual demand of the engine at any engine speed, the excess fuel returns to the rotary plate pump inlet through the oil return channel provided by the control unit. Due to the incompressibility of oil, the control unit actually ensures the main pump output suitable fuel pressure by returning the oil from the output end of the supercharging unit. The control unit provides two parallel oil return channels for the output end of the rotary plate pump, one of which is composed of the main valve and the slow valve in series, the fuel enters the intermediate oil chamber through the main valve and then flows to the oil return chamber through the slow valve, and the other is independently composed of the mixture ratio valve, which is closed under normal conditions and manually controlled by the valve opening degree when needed. Figure 1 The main valve and the slow valve are shown to return the output oil chamber. The engine reference operating point drift of the present invention is located in the slow valve part.

[0031] The slow valve is a disc-shaped valve sleeved on the core column and axially movable along the core column, and the core column is a cylindrical straight guide rod fixed on the base. The two ends of the valve body have different cross-sectional areas, and a blind hole is formed in the center of the large end in the axial direction to sleeve the core column and cooperate with the core column to provide circumferential positioning for the valve. The slow valve is in front of the intermediate oil chamber and behind the oil return chamber, and the fuel pressure difference between the intermediate oil chamber and the oil return chamber provides the slow valve opening force; the small end of the slow valve body is attached to the fuel film, and the slow oil pressure spring is pressed against the small end face of the slow valve body through the fuel film to provide the slow valve closing force, and the slow valve body moves axially on the core column based on the certain spring pre-tightening force according to different intermediate oil chamber oil pressures, thereby changing the gap between the valve body and the base and changing the valve opening. The fuel film provides sealing and isolation between the oil return chamber and the diaphragm chamber cavity where the slow oil pressure spring is located, and adjusting the slow oil pressure adjusting screw changes the axial position of the screw shaft, changes the slow oil pressure spring pre-tightening force on the slow valve body, and controls the basic oil return amount of the intermediate oil chamber through the slow valve.

[0032] The output oil pressure of the fuel pump driven by the engine at its idle calibration speed of 600 rpm determines the engine's reference operating point. After setting the engine's reference operating point, the idle valve will reach equilibrium under the combined action of a certain intermediate oil chamber fuel pressure and the idle oil pressure spring, maintaining a certain opening degree, which is called the reference opening degree. Correspondingly, the position of the idle valve body on the mandrel at this time is also called the reference position. After the engine speed changes, the amount of fuel output by the turbocharger changes. Due to the incompressibility of the oil, this will cause a change in the oil pressure in the intermediate oil chamber in front of the idle valve, breaking the equilibrium of the idle valve body. The idle valve body moves left and right on the mandrel and reaches equilibrium at a new position. At this time, the idle valve opening changes, and the return oil volume changes. The idle valve opening reaches its maximum under full throttle. Undoubtedly, the engine's reference operating point should be stable. When the engine operates at other power levels and then the throttle is released again to the idle calibration speed of 600 rpm, the idle valve body should be able to return to the reference position. However, engineering practice shows that on some TCM IO360ES engines, after full throttle and then returning to 600 km / h... rpm After calibrating the engine at idle, it was found that the output oil pressure of the engine-driven fuel pump was lower than the previous setting value, indicating that the idle valve body did not return to the reference position as expected. The opening of the idle valve was greater than the reference opening, which led to an increase in the return oil volume of the "large valve-idle valve" return oil channel, that is, the reference operating point of the engine was offset.

[0033] Engineering practice shows that the performance drift of an engine-driven fuel pump always tends towards a decrease in output pressure. This leads to a lean fuel ratio at idle, and exceeding a certain threshold will induce a premature engine shutdown due to excessive lean fuel consumption. While the deviation is absolute, the acceptable level is relative. Engine-driven fuel pumps with excessive deviations should be deemed unacceptable and replaced. This screening criterion involves a secondary test conducted on engine-driven fuel pumps that have passed factory testing during aircraft operation. The screening standard is higher than the manufacturer's factory standard. This targeted operational judgment method and screening standard are not disclosed in manufacturer or related engineering technology literature, and is one of the innovations of this invention.

[0034] The secondary screening test of the engine-driven fuel pump qualified in the factory test is based on the normal operation state of the TCM IO360ES engine installed with the pump on the aircraft, the method, key control parameters and threshold values used in the secondary screening test are inseparable from the configuration of the carrier aircraft of the TCM IO360ES engine. Since the normal operation idle speed of the Cirrus SR20 aircraft is 800±50 rpm, and there is no engine fuel system pressure gauge installed on the aircraft, the engine fuel pressure parameter cannot be read from the on-board instrument of the aircraft in the normal operation state of the aircraft. The technical scheme of the application fully considers the environmental conditions in the aircraft operation link, and adopts the secondary screening with the fuel flow stability at the normal operation idle speed of 800±50 rpm as the index, which is not disclosed in the factory and related engineering technical field documents, and is the second innovation point of the application.

[0035] Principle of throttle meter performance drift

[0036] On the TCM IO360ES aviation piston engine, the function of the throttle meter is to provide appropriate fuel supply for the engine according to the opening degree of the throttle valve, so as to ensure that the mixture in the engine cylinder is at an appropriate fuel-air ratio under different power states. In order to achieve this function, the throttle meter includes a venturi, a throttle valve located at the throat of the venturi, and a fuel control device connected to the throttle valve shaft, wherein the throttle valve cooperates with the venturi wall to control the amount of air entering the engine cylinder, and the fuel control device connected to the throttle valve shaft controls the amount of fuel supply according to the amount of air intake, and the fuel control device also provides the function of adjusting the fuel supply separately under the slow running state of the engine, so as to adjust the oil-gas ratio of the mixture in the engine cylinder under the slow running state of the engine.

[0037] The fuel control device is composed of a moving disc, a static disc, an adjusting screw and a compression spring, the moving disc and the static disc are two discs that are attached together but can rotate relative to each other. The moving disc is connected to the throttle valve shaft through the inner hexagonal hole seat on its side to realize synchronous rotation with the throttle valve, and the local circumference of the moving disc is cut off to form a variable radius circumference; the static disc is a disc with the same diameter as the moving disc, and the static disc has a constant flow hole and a pin, after the static disc and the moving disc are attached together, the variable radius circumference of the moving disc can partially block the constant flow hole on the static disc, and the relative rotation between the moving disc and the static disc can change the effective opening of the constant flow hole. Figure 2). The pin on the static disc is used to slightly adjust the circumferential position of the flow hole on the static disc. The pin is pressed on the adjusting screw by a spring. When the moving disc does not rotate, i.e. corresponding to a certain throttle opening, rotating the adjusting screw can realize small amplitude rotation of the static disc in the clockwise or counterclockwise direction, thereby slightly changing the effective opening of the flow hole on the static disc, and realizing small amplitude adjustment of the oil supply amount when the throttle position is unchanged Figure 3 ). Under normal circumstances, the pin is pressed on the adjusting screw by the spring, thereby fixing the spatial angular position of the static disc. At this time, the moving disc rotates synchronously with the throttle, and through the different degrees of shielding of the variable radius periphery with different radii on the moving disc to the flow hole on the static disc, the purpose of changing the oil supply amount with the throttle opening is realized.

[0038] Under ideal conditions without considering the fatigue of the spring, the pin on the static disc will be pressed tightly on the end of the adjusting screw by the spring. Without rotating the adjusting screw, the circumferential position of the static disc does not change, but in fact it is not like this. In actual work, the moving disc and the static disc are attached together, and during the process of changing the throttle opening, the moving disc and the static disc rotate relatively, and the friction force existing on the joint surface between the moving disc and the static disc will try to make the static disc rotate with the moving disc. This trend needs to be balanced by the elastic force of the spring during the oil gate stroke, and needs to be balanced by the stopping force of the adjusting screw during the oil gate stroke. With the increase of service time, the spring appears fatigue, and the elastic force of the spring is not enough to press the pin on the static disc tightly on the end of the adjusting screw during the oil gate (counterclockwise rotation of the moving disc), resulting in that the static disc will rotate unexpectedly with the moving disc. The result of this influence is that the actual opening of the flow hole is smaller than expected, causing the actual oil supply amount of the engine to decrease during the entire oil gate process, which affects the normal work of the engine.

[0039] It can be seen that the throttle metering body will have performance drift due to its structural design and performance characteristics, causing the actual oil-gas ratio of the engine to deviate, making the oil-gas ratio of the mixture in the cylinder of the engine deviate from the preset state, and causing the engine to work abnormally. Engineering practice shows that the performance drift of the throttle metering body is always in the direction of reducing the oil supply amount of the engine during the oil gate process, which will lead to the engine accelerating without power and being poor in oil at high power, and exceeding a certain threshold will induce early combustion / knock, valve ablation and other serious engine failures. Therefore, the deviation is absolute, and the qualification is relative. The throttle metering body with too large deviation should be judged as unqualified and replaced. This screening standard is a secondary test on the throttle metering body that has passed the factory test in the aircraft operation link, and the screening standard is higher than the factory standard. This targeted operation judgment method and screening standard have not been disclosed in the literature of the factory and related engineering technical fields, and is the third innovation point of the application.

[0040] The secondary screening test of the oil metering body qualified by the factory test in the aircraft operation link is based on the normal operation state of the TCM IO360ES type engine installed with the oil metering body on the aircraft, the method, key control parameters and threshold values used in the secondary screening test are inseparable from the configuration of the carrier aircraft of the TCM IO360ES type engine. Since there is no engine fuel system pressure gauge installed on the Cirrus SR20 aircraft, the engine fuel pressure parameter cannot be read from the on-board instruments of the aircraft in the normal operation state of the aircraft. The technical solution fully considers the environmental conditions in the aircraft operation link, adopts the fuel flow stability in the medium speed (1700rpm) state of the normal operation of the aircraft as the index for secondary screening, which is not disclosed in the factory and related engineering technical field documents, and is the fourth innovation point of the present application.

[0041] Any mechanical component will have performance changes caused by various influencing factors such as wear and tear and changes in environmental conditions in use. How to effectively monitor the performance drift of the engine driven fuel pump and the throttle metering body under the condition of aircraft operation and how to make quantitative judgment are not disclosed in the related technical documents of aircraft and engine manufacturers and industry fields. The present application proposes an operation method and judgment threshold capable of quantifying the performance drift of the engine driven fuel pump and the throttle metering body, thereby realizing effective evaluation of the performance of the core components of the TCM IO360ES type aviation piston engine fuel system. The evaluation method and judgment threshold do not require any professional equipment, can be seamlessly integrated into the engine test program of the aircraft, and are easy for flight personnel and maintenance personnel to operate in engineering practice. By performing the evaluation method and judgment threshold during engine test in aircraft operation, the reliability and monitoring and fault warning of the performance of the core components of the engine fuel system can be realized, achieving the purpose of real-time tracking and monitoring of engine performance, early detection of fault trend and improvement of engine operation reliability.

[0042] In the performance evaluation process of the engine-driven fuel pump for the purpose of survival of the fittest, the electric fuel booster pump in the aircraft fuel system needs to be started during the take-off and landing stages of the actual operation, and the fuel film in the oil return chamber of the engine-driven fuel pump under the electric fuel booster starting state has an additional force to push the slow-speed valve opening to increase. Therefore, the slow-speed valve opening of the engine-driven fuel pump will be further increased when the electric fuel booster is started during the full throttle take-off of the aircraft. The test of the slow-speed stability of the engine-driven fuel pump should simulate the actual operation state of the aircraft to make the slow-speed valve opening as large as possible, and then the throttle is retracted to test the ability of the slow-speed valve to reset to the reference opening. Through the secondary screening of the engine-driven fuel pump that has passed the factory test under the normal operation condition of the aircraft, the slow-speed fuel flow stability at the typical slow-speed rotating speed of 800±50 rpm is taken as the index, mainly in the engine ground test, the performance stability of the engine-driven fuel pump is measured by simulating various use states of the engine in the actual operation of the aircraft and taking the fuel flow drift as the quantitative index.

[0043] In the performance evaluation process of the engine throttle metering body for the purpose of survival of the fittest, the performance drift of the throttle metering body is always towards the direction of reducing the engine fuel supply during the throttle opening process, which will lead to the engine acceleration weakness and the poor oil supply at high power, and exceeding a certain threshold will induce early combustion / knock, valve ablation and other serious engine failures. Since this performance drift can only be shown during the throttle opening process, and in order to avoid the adverse effects of poor oil supply at high power on the engine, the selected test rotating speed range of the application is 1700±50 rpm, and the corresponding percentage power range is about 30%. Through the secondary screening of the engine throttle metering body that has passed the factory test under the normal operation condition of the aircraft, the engine fuel flow stability at the typical test rotating speed is taken as the index, mainly in the engine ground test, the performance stability of the engine throttle metering body is measured by taking the fuel flow drift at the typical test rotating speed as the quantitative index.

[0044] Through the adoption of the above technical solutions, the application has the following beneficial effects:

[0045] The reference working point deviation of the engine-driven pump can be conveniently monitored

[0046] Since there is no on-board fuel pressure gauge on the Cirrus SR20 aircraft, the fuel pressure parameter of the engine fuel system cannot be displayed in real time, but the on-board fuel flow gauge is configured on the aircraft, so the technical solution disclosed in the application uses the existing engine speed and engine fuel flow gauge on the aircraft to complete the judgment and monitoring of the key indicators such as the reference working point deviation of the main pump, and no longer needs to access special equipment and reset the normal slow vehicle speed of the engine to 600 rpm to measure and judge, which is simple and easy to operate, and can be completed "incidentally" in normal operation.

[0047] 2. Convenient monitoring of the performance deviation of the throttle metering body

[0048] The performance characteristics, judgment method and parameter standard of the TCM IO360ES aviation piston engine throttle metering body are not disclosed by the aircraft and engine manufacturers, and there is no related academic research report in the field of aviation maintenance engineering, and the traditional method cannot realize the performance evaluation and reliability monitoring of the throttle metering body of the engine. Therefore, the technical solution disclosed in the application uses the existing engine speed and engine fuel flow gauge on the aircraft to complete the judgment and monitoring of the key indicators such as the performance deviation of the engine throttle metering body, and the operation method is simple and easy to operate, and can be completed "incidentally" in normal operation.

[0049] 3. The parameter setting has a basis to follow, the troubleshooting and replacement have a target, the process is simple and effective, the waste of manpower and material resources is reduced, the economic indicators are good, the quantitative evaluation and judgment of the fault performance of the core components of the engine fuel system are realized with the minimum cost, the real-time control and fault warning of the engine performance are realized, and the efficiency of ensuring flight safety is effectively improved.

[0050] Before using the method, the performance characteristics, judgment method and parameter standard of the core components of the TCM IO360ES aviation piston engine fuel system are not disclosed by the aircraft and engine manufacturers, and there is no related academic research report in the field of aviation maintenance engineering, and the core components of the engine fuel system with large performance drift and poor working stability are difficult to effectively detect, resulting in frequent occurrence of many difficult faults such as engine slow vehicle parking, pre-ignition / knocking and valve sticking of the Cirrus SR20 aircraft for a long time, and it is difficult to effectively solve despite paying a lot of manpower and material resources.

[0051] During the verification of the technical solution adopted in the application in engineering practice, through the secondary screening of the performance of the core components of the TCM IO360ES aviation piston engine fuel system, the parameter setting has a basis to follow, the troubleshooting and replacement have a target, the process is simple and effective, the waste of manpower and material resources is reduced, and the economic indicators are good. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is the schematic diagram of the return oil passage of the output oil chamber composed of the slow-moving car valve and the slow-moving valve in the engine-driven fuel pump.

[0053] Figures 2 to 5 is the control device and component structure and assembly relationship diagram of the fuel control part in the throttle metering body; the fuel control device of the throttle metering body is composed of a moving disc, a static disc, a spring and an adjusting screw. Figures 2 to 5 In the method, the end face of the moving disc has an internal hexagonal hole seat at the center position, and a partial radius-changing peripheral edge is formed by removing part of the material at the edge; the end face of the static disc has a round hole near the peripheral edge position; and a pin is arranged at the position opposite to the round hole. The moving disc is connected with the throttle shaft through the internal hexagonal hole seat of the end face, and the moving disc can rotate synchronously with the throttle; the pin on the static disc is pressed on the end face of the adjusting screw by the spring, and the static disc remains stationary when the adjusting screw is not rotated. Rotating the adjusting screw can change the circumferential angle of the static disc in a small range. The moving disc and the static disc are attached together but can rotate relatively, and the partial radius-changing peripheral edge of the moving disc can partially block the constant flow hole on the static disc. When the moving disc and the static disc rotate relatively, the effective opening of the constant flow hole can be changed, so that the oil supply amount is changed.

[0054] In the method, Figure 2 is a structural schematic diagram of the moving disc.

[0055] Figure 3 is a structural schematic diagram of the static disc.

[0056] Figure 4 is a static disc side schematic diagram of the combination of the moving disc, the static disc, the spring and the screw.

[0057] Figure 5 is a moving disc side schematic diagram of the combination of the moving disc, the static disc, the spring and the screw; in the diagram, the spring and the screw are blocked and cannot be directly seen.

[0058] Figure 6 is an assembly schematic diagram of the moving disc, the static disc, the spring and the adjusting screw.

[0059] 1 - slow-moving car valve, 2 - output oil chamber, 3 - intermediate oil chamber, 4 - slow-moving valve, 5 - return oil chamber, 6 - core column, 7 - fuel film, 8 - membrane box cavity air hole, 9 - slow-moving oil pressure adjusting screw, 10 - slow-moving oil pressure spring, 11 - moving disc, 12 - internal hexagonal hole seat, 13 - round hole, 14 - pin, 15 - static disc, 16 - pin, 17 - spring, 18 - adjusting screw, 19 - constant flow hole. Embodiment

[0060] The method for evaluating the performance of the core components of the TCM IO360ES engine fuel system comprises the following specific implementation process:

[0061] First stage: the engine driven fuel pump performance evaluation for the purpose of survival of the fittest, the implementation steps as follows:

[0062] Start the engine control engine speed does not exceed 1200 rpm, warm-up to the green zone of the oil temperature;

[0063] Step 2: throttle back to slow car, in the engine normal operation slow car state, record the engine slow car fuel flow value, set as the first fuel flow F1;

[0064] Specifically, the normal operation slow car state refers to the engine slow car speed of 800 ± 50 rpm ；

[0065] Step 3: push the throttle to the maximum power position and start the electric fuel booster pump, after 2-6s of full throttle operation, throttle back, and turn off the electric fuel booster pump when the engine speed is about 1700 ± 150 rpm;

[0066] Step 4: continue to throttle back to slow car, and record the engine fuel flow value again, set as the second fuel flow F2;

[0067] Step 5: calculate the difference between the first fuel flow and the second fuel flow, set the difference as ΔF 12 ; the greater the difference, the worse the stability of the engine driven fuel pump; if ΔF 12 > 0.2gph, it can be determined that the performance of the engine driven fuel pump cannot meet the normal operation requirements, and the pump should be replaced.

[0068] Second stage: engine throttle metering body performance evaluation for the purpose of survival of the fittest

[0069] Step 1: start the engine control engine speed does not exceed 1200 rpm, warm-up to the green zone of the oil temperature;

[0070] Step 2: slowly push the throttle to stabilize the engine speed at 1700 ± 50 rpm, and there should be no throttle back operation during this process;

[0071] If the throttle is pushed too much and the engine speed exceeds 1700 rpm, throttle back to reduce the engine speed to below 1650 rpm, and then slowly push the throttle to stabilize the engine speed at 1700 rpm.

[0072] Step 3: record the engine fuel flow value at this time, set as the third fuel flow F3;

[0073] Step 4: continue to push the throttle to increase the engine speed to above 1800 rpm;

[0074] Step 5: Slowly reduce the engine speed and stabilize it at 1700±50rpm, and no throttle should be operated during this process;

[0075] If the throttle is closed too much and the engine speed is lower than 1700rpm, then step 4 and step 5 must be re-executed;

[0076] Step 6: Record the engine fuel flow value at this time, set as the fourth fuel flow F4;

[0077] Step 7: Calculate the difference between the third fuel flow F3 and the fourth fuel flow F4, and set the difference as ΔF 34 The larger the difference, the worse the stability of the throttle metering body; if ΔF 34 >0.2gph, then it can be determined that the performance of the throttle metering body cannot meet the normal operation requirements, and the throttle metering body needs to be replaced.

[0078] Data statistics:

[0079] Before the use of the technical scheme, 40 Cirrus SR20 aircrafts of an aviation operation unit ran for 50 calendar months, with a total running time of 140870 hours, and 75 slow-speed parking failures occurred, with an average failure rate of 1878 hours per occurrence, 1.5 occurrences per calendar month. The average economic loss caused by each slow-speed parking failure is 24400 yuan.

[0080] After the use of the technical scheme, 40 Cirrus SR20 aircrafts of the aviation operation unit ran for 5.5 calendar months, with a total running time of 25474 hours, and 3 slow-speed parking failures occurred, with an average failure rate of 4631 hours per occurrence, 0.5 occurrences per calendar month.

[0081] After the complete use of the technical scheme, the 40 Cirrus SR20 aircrafts of the aviation operation unit have been running continuously for more than 85 calendar months, with a total running time of more than 330000 hours, and no slow-speed parking failure has occurred.

[0082] Practical evidence shows that the method can effectively eliminate the stubborn slow-speed parking failure of Cirrus SR20 aircrafts which has not been effectively solved in the industry for many years, and has a significant effect on ensuring flight safety and obvious social benefits.

Claims

1. A method of evaluating the performance of core components of the fuel system of a TCM IO360 ES engine, characterized by The specific process is as follows: The first stage: the engine driven fuel pump performance evaluation for the purpose of survival of the fittest, the implementation steps are as follows: Step 1: start the engine to control the engine speed not more than 1200 rpm, warm-up to the oil temperature into the green zone; Step 2: the throttle is retracted to the slow car position, the engine slow car fuel flow value is recorded under the condition of normal operation of the engine slow car, which is set as the first fuel flow F1; Step 3: push the throttle to the maximum power position and start the electric fuel booster pump, after working for 2-6s under full throttle, retract the throttle, and turn off the electric fuel booster pump when the engine speed is 1700±150 rpm; Step 4: continue to retract the throttle to the slow car position, and record the engine fuel flow value again, which is set as the second fuel flow F2; Step 5: Calculate the difference between the first and second fuel flow rates, and let the difference be ΔF 12 ; the greater the difference, the worse the stability of the engine-driven fuel pump; if ΔF 12 > 0.2 gph, then the performance of the engine-driven fuel pump cannot meet the normal operation requirements, and the pump should be replaced. The second stage: engine throttle metering body performance evaluation for the purpose of survival of the fittest; Step 1: start the engine to control the engine speed not more than 1200 rpm, warm-up to the oil temperature into the green zone; Step 2: the engine speed is stabilized at 1700±50 rpm by slowly pushing the throttle; Step 3: record the engine fuel flow value at this time, which is set as the third fuel flow F3; Step 4: continue to push the throttle to increase the engine speed to more than 1800 rpm; Step 5: slowly retract the throttle to reduce the engine speed and stabilize it at 1700±50 rpm; If the throttle is retracted too much to cause the engine speed to be lower than 1700 rpm, the fourth and fifth steps of the second stage must be re-executed; Step 6: record the engine fuel flow value at this time, which is set as the fourth fuel flow F4; Step 7: Calculate the difference between the third fuel flow F3 and the fourth fuel flow F4, and set the difference as ΔF 34 The greater the difference, the worse the stability of the throttle meter; if ΔF 34 > 0.2 gph, it is determined that the performance of the throttle meter cannot meet the normal operation requirements, and the throttle meter needs to be replaced.

2. The method of claim 1, wherein the performance of the core components of the TCM IO360 ES engine fuel system is evaluated by: The normal operation slow car state described in the first stage refers to the state of the engine slow car speed of 800±50 rpm.

3. The method of evaluating the performance of the core components of the TCM IO360ES engine fuel system of claim 1, wherein: When measuring the characteristic speed, the fuel flow at the engine characteristic speed is used as the characteristic parameter, and the qualified threshold is 0.2gph; the first stage characteristic speed is the normal operation slow car speed of 800±50 rpm, and the second stage characteristic speed is 1700±50 rpm.

4. The method of evaluating the performance of the core components of the TCM IO360 ES engine fuel system of claim 1, wherein: The first half of the test preparation work of the second stage is to stabilize the engine speed at 1700±50 rpm by slowly pushing the throttle, and this process cannot have the throttle retraction action; if the engine speed exceeds 1700 rpm, the throttle is retracted to reduce the engine speed to below 1650 rpm, and then the slowly pushing the throttle is repeated to stabilize the engine speed at 1700±50 rpm.

5. The method of claim 1, wherein the performance of the core components of the TCM IO360 ES engine fuel system is evaluated by: The second half of the test preparation work of the second stage is to continue to push the throttle to make the engine speed reach more than 1800 rpm, and then slowly retract the throttle to reduce the engine speed and stabilize it at 1700±50 rpm, and this process cannot have the throttle pushing action.

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