Engine fuel flow linear continuous regulation system and method

Abstract

The present application relates to a ramjet engine wind tunnel test method, and particularly relates to an engine fuel flow linear continuous regulation system and method, which solves the problem that the existing ground wind tunnel single test fuel continuous linear regulation method is difficult to accurately obtain the lean and rich oil boundaries of the engine, resulting in low test efficiency and high test cost. The engine fuel flow linear continuous regulation system comprises a fuel storage tank, an automatic supercharging module, a second pneumatic valve and a control module; the outlet of the fuel storage tank is sequentially provided with an isolation valve, a flow meter, a flow regulating valve and a first pneumatic valve in the flow direction of the fuel, and the first pneumatic valve is connected with the engine through a pipeline; the second pneumatic valve is used to release the internal pressure of the fuel storage tank after the test is completed; the automatic supercharging module, the flow meter, the first pneumatic valve, the second pneumatic valve, the flow regulating valve and the pressure gauge are respectively in communication connection with the control module, and the control module is used to change the opening of the flow regulating valve by controlling the current of the flow regulating valve, so as to realize the linear continuous regulation of the engine fuel flow.

Description

TECHNICAL FIELD

[0001] The present application relates to a ramjet engine wind tunnel test method, and in particular to an engine fuel flow linear continuous regulation system and method. BACKGROUND

[0002] In the ground wind tunnel test of a combined engine, the lean and rich boundaries of the engine combustion chamber need to be studied, and the engine fuel supply is provided by the test stand. When the fuel flow is close to the lean and rich boundaries of the engine, a small change in fuel flow may cause the boundaries to be unobtainable, affecting the development progress of the engine.

[0003] The existing single test time of the ground wind tunnel is in the order of 20s, and the fuel flow regulation method can realize multiple stepwise switching regulation of the fuel flow in one test, and multiple ground wind tunnel single tests are needed to obtain the lean and rich boundaries of the engine. At the same time, due to the large difference between each fuel flow, there is a defect of low accuracy of the lean and rich boundaries of the fuel flow. In order to shorten the cycle of multiple ground wind tunnel single tests and reduce the test cost, a better continuous linear regulation method of fuel is urgently needed to ensure that the lean and rich boundaries of the engine under a certain working condition can be obtained in a single ground wind tunnel test. SUMMARY

[0004] The purpose of the present application is to solve the problem that the existing continuous linear regulation method of fuel in a single test of the ground wind tunnel is difficult to accurately obtain the lean and rich boundaries of the engine, resulting in low test efficiency and high test cost, and to provide an engine fuel flow linear continuous regulation system and method.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0006] An engine fuel flow linear continuous regulation system, characterized in that it comprises a fuel tank, an automatic supercharging module, a second pneumatic valve and a control module.

[0007] The top of the fuel tank is provided with an inlet, and the bottom is provided with an outlet.

[0008] The automatic supercharging module is connected with an external gas source at one end and connected with the inlet of the fuel tank at the other end, and is used for supercharging the inside of the fuel tank.

[0009] The outlet of the fuel tank is sequentially provided with an isolation valve, a flow meter, a flow regulating valve and a first pneumatic valve along the flow direction of the fuel, and the first pneumatic valve is connected with the engine through a pipeline.

[0010] The second pneumatic valve is arranged in the inlet of the fuel tank through a pipeline, and is used for releasing the pressure inside the fuel tank after the test is finished.

[0011] Pressure gauges are installed at the air inlet of the automatic boost module, the top of the fuel tank, between the flow control valve and the first pneumatic valve, and between the first pneumatic valve and the engine.

[0012] The automatic booster module, flow meter, first pneumatic valve, second pneumatic valve, flow regulating valve, and pressure gauge are all communicatively connected to the control module. The control module is used to change the opening degree of the flow regulating valve by controlling the current of the flow regulating valve, thereby achieving linear and continuous regulation of the engine fuel flow.

[0013] Furthermore, the automatic booster module includes at least two pressure-stabilizing pipes connected in parallel; each pressure-stabilizing pipe is equipped with a solenoid valve that is communicatively connected to the control module;

[0014] One end of the pressure stabilizing pipeline is connected to an external gas source, and the other end is connected to the inlet of the fuel tank.

[0015] Furthermore, it also includes a filter installed between the isolation valve and the flow meter.

[0016] Meanwhile, the present invention also provides a method for linear and continuous adjustment of engine fuel flow, which is characterized by including the following steps:

[0017] 1. Construct the above-mentioned linear and continuous fuel flow regulation system for the engine;

[0018] 2. Debug the system and adjust the flow rate according to the flow control valve's range [Q]. min Q max ], calculate the control current range of the flow regulating valve [A min A max ] and flow control valve opening [K min K max ];

[0019] 3. Define the response time of the flow control valve as T1, the execution time as T2, and the current recognition accuracy as △A; set the total test time as T, the preset time interval as the execution time T2, and calculate the number of adjustment actions X of the flow control valve based on the total test time T and the preset time interval T2.

[0020] 4) Based on the control current range [A] min A max ] Calculate the control current interval A based on the number of adjustment actions X;

[0021] 5. Determine whether the control current interval A is greater than the current recognition accuracy ΔA;

[0022] If so, then divide the control current interval A to complete the linear and continuous adjustment of engine fuel flow; otherwise, readjust the preset time interval and return to step 3.

[0023] Further, the step 2 is specifically:

[0024] 2.1, according to the flow regulating range of the flow regulating valve [Q min , max ], the fuel flow coefficient C v is calculated by the following formula:

[0025]

[0026] In the formula, Q is the fuel flow; G is the relative density of fuel; ΔP is the pressure difference between the fuel tank and the engine inlet;

[0027] 2.2, debugging the engine fuel flow linear continuous regulation system, obtaining the fitting curve of the fuel flow coefficient C v and the control current of the flow regulating valve;

[0028] 2.3, according to the fitting curve, the control current range [A min , A max ] of the flow regulating valve is obtained;

[0029] 2.4, according to the control current range [A min , A max ], the opening degree [K min , K max ] of the flow regulating valve is determined.

[0030] Further, in the step 3, the calculation of the regulating action times X of the flow regulating valve is specifically:

[0031] According to the total test time T and the preset time interval T2, the regulating action times X of the flow regulating valve is calculated by the following formula:

[0032]

[0033] Further, the step 4 is specifically:

[0034] According to the control current range [A min , A max ] and the regulating action times X, the control current interval A is calculated by the following formula:

[0035]

[0036] Further, in the step 4, the control current interval A is divided into equal intervals.

[0037] The beneficial effects of the present application are:

[0038] 1. The engine fuel flow linear continuous regulation system of the present application, through the automatic supercharging module continuously gas extrusion supply to the fuel tank, keeps the fuel tank pressure constant (i.e. the pressure at the inlet of the flow regulating valve is constant), adjusts the outlet pressure by changing the opening of the flow regulating valve, realizes the linear regulation of the fuel flow.

[0039] 2. The engine fuel flow linear continuous regulation system of the present application, the flow meter is installed on the fuel pipeline in front of the flow regulating valve, can obtain the real-time fuel flow, to ensure the accuracy of the fuel flow measurement.

[0040] 3. The engine fuel flow linear continuous regulation method of the present application, one test can obtain the working data of the engine at each flow, to judge the working state of the engine, and then determine the lean and rich boundaries of the engine, so that the experimental efficiency is greatly improved, and the problem of difficult to accurately obtain the lean and rich boundaries of the engine combustion chamber in a single test is solved.

[0041] 4. The engine fuel flow linear continuous regulation method of the present application, can realize the wide range linear continuous regulation of the fuel flow in a limited test time, and the regulation range can reach 10 times. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a structural schematic diagram of an embodiment of the engine fuel flow linear continuous regulation system of the present application.

[0043] MARKED FOR EXPLANATION:

[0044] 1-fuel tank, 2-automatic supercharging module, 21-solenoid valve, 3-isolation valve, 4-flow regulating valve, 5-flow meter, 6-first pneumatic valve, 7-second pneumatic valve, 8-pressure gauge, 9-filter. DETAILED DESCRIPTION

[0045] As shown in Figure 1 , an engine fuel flow linear continuous regulation system, comprising a fuel tank 1, an automatic supercharging module 2, a second pneumatic valve 7 and a control module; the top of the fuel tank 1 is provided with an inlet, and the bottom is provided with an outlet; one end of the automatic supercharging module 2 is connected with an external gas source, and the other end is connected with the inlet of the fuel tank 1, for supercharging the inside of the fuel tank 1; in this embodiment, the external gas source is nitrogen. When the fuel flow of the engine is lower than a certain flow value, the power of the engine is insufficient, which causes unstable operation, and even engine stall, at this time, it is in a lean state; when the fuel flow of the engine is higher than a certain flow value, its combustion is not sufficient, which causes power drop and fuel consumption increase, at this time, it is in a rich state.

[0046] Along the fuel flow direction, the outlet of fuel tank 1 is sequentially equipped with an isolation valve 3, a flow meter 5, a flow regulating valve 4, and a first pneumatic valve 6. The flow meter 5 is installed on the fuel line before the flow regulating valve 4 to obtain real-time fuel flow rate, ensuring the accuracy of fuel flow measurement. The first pneumatic valve 6 is connected to the engine via a pipeline. The second pneumatic valve 7 is installed at the inlet of fuel tank 1 via a pipeline to release the internal pressure of fuel tank 1 after the test. Pressure gauges 8 are installed at the air inlet of the automatic boost module 2, the top of fuel tank 1, between the flow regulating valve 4 and the first pneumatic valve 6, and between the first pneumatic valve 6 and the engine. A filter 9 is installed between the isolation valve 3 and the flow meter 5. The automatic boost module 2, flow meter 5, first pneumatic valve 6, second pneumatic valve 7, flow regulating valve 4, and pressure gauges 8 are all communicatively connected to the control module. The control module is used to control the current of the flow regulating valve 4 to change its opening, thereby achieving linear and continuous adjustment of the engine fuel flow.

[0047] The automatic boost module 2 includes three pressure regulating pipes; each pressure regulating pipe is equipped with a solenoid valve 21 that communicates with the control module; one end of the pressure regulating pipe is connected to an external air source, and the other end is connected to the inlet of the fuel tank 1.

[0048] Meanwhile, the present invention also provides a method for linear and continuous adjustment of engine fuel flow, comprising the following steps:

[0049] 1. Construct the above-mentioned linear and continuous fuel flow regulation system for the engine;

[0050] 2. Debug the system and adjust the flow rate according to the flow rate adjustment range of flow regulating valve 4 [Q]. min Q max ], calculate the control current range of flow regulating valve 4 [A min A max ] and flow regulating valve 4 opening degree [K min K max ];

[0051] 2.1 According to the flow regulation range of flow regulating valve 4 [Q] min Q max The fuel flow coefficient C is calculated using the following formula. v Scope:

[0052]

[0053] In the formula, Q is the fuel flow rate; G is the relative density of the fuel; ΔP is the pressure difference between the fuel tank pressure and the engine inlet.

[0054] 2.2 Debug the engine fuel flow linear continuous adjustment system and obtain the fuel flow coefficient C. v Fitting curve of the control current of flow regulating valve 4;

[0055] 2.3, according to the fitting curve, obtain the control current range [A min , A max ] of the flow regulating valve 4;

[0056] 2.4, since the opening of the flow regulating valve 4 and the control current current are linearly related, according to the control current range [A min , A max ], determine the opening [K min , K max ] of the flow regulating valve 4;

[0057] In this embodiment, according to the fuel flow Q and the above formula, the maximum fuel flow Q max and the minimum fuel flow Q min corresponding Cv value can be calculated, that is, the maximum control current A max and the minimum control current A min . Since the opening K of the flow regulating valve 4 and the control current current A are linearly related, when the control current A = 4mA, the opening K min of the flow regulating valve 4 is 0%; when the control current current A = 20mA, the opening K max of the flow regulating valve 4 is 100%.

[0058] 3] Define the response time of the flow regulating valve 4 as T1, the execution time as T2, and the current recognition accuracy as △A; set the total test time as T, the preset time interval as the execution time T2, and calculate the adjustment action times X of the flow regulating valve 4 according to the total test time T and the preset time interval T2 by the following formula:

[0059]

[0060] The response time of the flow regulating valve 4 is T1, and the execution time is T2, which remains consistent in the small action range. The time interval required for the flow regulating valve 4 to start each action to the action to the position is set as the execution time T2, and then each step action will maintain continuous relay with the previous step action. If the time interval of each step exceeds T2, the opening curve of the flow regulating valve 4 (the opening amplitude of the flow regulating valve 4 under different control currents is different, which is generally 0% ~ 100%) will appear a stable segment at each step.

[0061] 4] According to the control current range [A min , A max ] and the adjustment action times X, calculate the control current interval A by the following formula:

[0062]

[0063] In this embodiment, the flow regulating valve 4 is adjusted according to the parameters in Table 1;

[0064] Table 1

[0065] Time (s) Current (mA) Flow (g / s) / opening degree 0 A min ]]> Q min / K min ]]> [T2] A min +A]]> … 2T2 A min +2A]]> … 3T2 A min +3A]]> … … … … [ T-T2 ] A max -A]] … T A max ]] Q max / K max ]]>

[0066] 5】determine whether the control current interval A is greater than the current identification precision ΔA, if yes, divide the control current interval A by equal difference, and complete the linear continuous regulation of the engine fuel flow; otherwise, readjust the preset time interval and return to step 3】.

[0067] The number of adjustment actions X of the flow regulating valve 4 is determined according to the total test time T and the preset time interval T2, the control current interval A is divided by equal difference, each step change control current ΔA, when A > ΔA, the next step change of the opening of the flow regulating valve 4 will just coincide with the end of the time of the last step change of the opening, ensuring the linear change of the opening of the flow regulating valve 4 and realizing the linear regulation of the fuel flow; when A≤ΔA, the flow regulating valve 4 does not respond in some regulation process, resulting in unstable fuel flow curve, therefore, coinciding with the rich boundary of the engine operation, the test data cannot be accurately obtained.

Claims

1. An engine fuel flow linear continuous regulation system characterized by: The system comprises a fuel tank (1), an automatic pressurization module (2), a second pneumatic valve (7) and a control module. The fuel tank (1) is provided with an inlet at the top and an outlet at the bottom. The automatic pressurization module (2) is connected with an external air source at one end and the inlet of the fuel tank (1) at the other end, for pressurizing the inside of the fuel tank (1). The outlet of the fuel tank (1) is sequentially provided with an isolation valve (3), a flow meter (5), a flow regulating valve (4) and a first pneumatic valve (6) along the flow direction of the fuel, and the first pneumatic valve (6) is connected with an engine through a pipeline. The second pneumatic valve (7) is arranged at the inlet of the fuel tank (1) through a pipeline, for releasing the pressure inside the fuel tank (1) after the test is finished. The automatic pressurization module (2) is provided with a pressure gauge (8) at the air inlet, the top of the fuel tank (1), between the flow regulating valve (4) and the first pneumatic valve (6), and between the first pneumatic valve (6) and the engine. The automatic pressurization module (2), the flow meter (5), the first pneumatic valve (6), the second pneumatic valve (7), the flow regulating valve (4) and the pressure gauge (8) are respectively in communication connection with the control module, and the control module is used for changing the opening of the flow regulating valve (4) by controlling the current, so as to realize the linear continuous regulation of the engine fuel flow. 1】Building an engine fuel flow linear continuous regulation system; 2】debugging system, and according to the flow regulation range [Q min ,Q max ] of the flow regulation valve (4), the control current range [A min , A max ] and the opening range [K min , K max ] of the flow regulation valve (4) are calculated; 3】Defining the response time of the flow regulating valve (4) as T1, the execution time as T2, and the current identification accuracy as △A; setting the total test time as T, the preset time interval as the execution time T2, and calculating the regulating action number X of the flow regulating valve (4) according to the total test time T and the preset time interval T2; 4】According to the control current range [A min , A max ] and the adjustment action number X, the control current interval A is calculated; 5】Judging whether the control current interval A is greater than the current identification accuracy △A; If yes, the control current interval A is divided, and the linear continuous regulation of the engine fuel flow is completed; otherwise, the preset time interval is adjusted again, and step 3】 is returned.

2. The engine fuel flow linear continuous regulation system according to claim 1, wherein: The automatic pressurization module (2) comprises at least two parallel pressure stabilizing pipelines; each pressure stabilizing pipeline is provided with an electromagnetic valve (21) in communication connection with the control module; One end of the pressure stabilizing pipeline is connected with an external air source, and the other end is connected with the inlet of the fuel tank (1).

3. The engine fuel flow linear continuous regulation system according to claim 2, further comprising a filter (9) arranged between the isolation valve (3) and the flow meter (5). Step 2】 is specifically:

4. The method of claim 3, wherein the engine fuel flow is linearly continuously adjusted by the engine control unit based on the engine speed and the engine load. In the formula, Q is the fuel flow; G is the relative density of the fuel; 2.

1. The range of the fuel flow coefficient C min , max is calculated by the following equation, in terms of the flow regulating range [Q v ] of the flow regulating valve (4). ΔP is the pressure difference between the fuel tank (1) and the engine inlet; In step 3】,the regulating action number X of the flow regulating valve (4) is calculated as follows: 2.2, Debugging engine fuel flow linear continuous regulation system, get fuel flow coefficient C v Fitting curve with flow regulating valve (4) control current; 2.

3. Obtain the control current range [A] of the flow regulating valve (4) according to the fitted curve min , A max ] 2.

4. Based on the control current range [A] min A max Determine the opening degree of the flow regulating valve (4) [K] min K max ].

5. The method of claim 4, wherein: According to the total test time T and the preset time interval T2, the regulating action number X of the flow regulating valve (4) is calculated by the following formula: Step 4】 is specifically:

6. The method of claim 5, wherein the step of linearly continuously adjusting the engine fuel flow rate is performed by a fuel flow rate control unit.

7. The engine fuel flow linear continuous regulation method according to claim 6, wherein: According to the control current range [A min , A max ] and the adjustment action number X, the control current interval A is calculated by the following equation: ​ In Step 4, the division control current interval A is divided equally.

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