Linear continuous adjusting system and method for fuel flow of engine

Abstract

The invention relates to a ramjet wind tunnel test method, in particular to an engine fuel oil flow linear continuous adjusting system and method, and solves the problems of low test efficiency and high test cost caused by difficulty in accurately obtaining lean oil and rich oil boundaries of an engine in an existing ground wind tunnel single test through a fuel oil continuous linear adjusting method. The linear continuous regulation system for the fuel flow of the engine comprises a fuel storage tank, an automatic pressurization module, a second pneumatic valve and a control module, an isolating valve, a flow meter, a flow regulating valve and a first pneumatic valve are sequentially arranged at an outlet of the fuel oil storage tank in the flowing direction of fuel oil, and the first pneumatic valve is used for being connected with an engine through a pipeline; the second pneumatic valve is used for releasing the internal pressure of the fuel oil storage tank after the test is finished; the automatic pressurization module, the flow meter, the first pneumatic valve, the second pneumatic valve, the flow adjusting valve and the pressure meter are in communication connection with the control module, and the control module is used for changing the opening degree of the flow adjusting valve by controlling the current of the flow adjusting valve to achieve linear continuous adjustment of the fuel flow of the engine.

Description

Technical Field

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

[0002] In the ground wind tunnel test of the 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 bench. When the fuel flow rate is close to the lean and rich boundaries of the engine, a slight change in the fuel flow rate may make it impossible to obtain the boundary, affecting the progress of engine development.

[0003] The existing single test time of ground wind tunnel is on the order of 20 seconds, while the fuel flow rate adjustment method can realize multiple fuel flow rate step-by-step switching adjustment in one test. It is necessary to conduct multiple single tests in ground wind tunnel to obtain the lean and rich boundaries of the engine. At the same time, due to the large difference between the fuel flow rates, there is a defect of low accuracy of the fuel flow rate at the lean and rich boundaries. In order to shorten the single test cycle of multiple ground wind tunnels and reduce the test cost, it is urgent to develop a better continuous linear fuel adjustment method to ensure that the lean and rich boundaries of a certain working condition of the engine can be obtained in a single test in the ground wind tunnel. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the existing continuous linear fuel regulation method in a single test in a 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 object, the present invention adopts the following technical solution:

[0006] An engine fuel flow linear continuous regulation system, which is special in that it includes a fuel tank, an automatic boost module, a second pneumatic valve and a control module;

[0007] The fuel tank is provided with an inlet at the top and an outlet at the bottom;

[0008] One end of the automatic pressurizing module is connected to an external gas source, and the other end is connected to the inlet of the fuel tank, so as to pressurize the inside of the fuel tank;

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

[0010] The second pneumatic valve is disposed at the inlet of the fuel tank through a pipeline, and is used to release the internal pressure of the fuel tank after the test is completed;

[0011] Pressure gauges are provided at the air inlet of the automatic supercharging module, the top of the fuel tank, between the flow regulating valve and the first pneumatic valve, and between the first pneumatic valve and the engine;

[0012] The automatic boost module, flow meter, first pneumatic valve, second pneumatic valve, flow regulating valve and pressure gauge are respectively connected to the control module for communication. The control module is used to change the opening of the flow regulating valve by controlling the current of the flow regulating valve to achieve linear and continuous regulation of the engine fuel flow.

[0013] Furthermore, the automatic boost module includes at least two pressure-stabilizing pipes connected in parallel; each pressure-stabilizing pipe is provided with a solenoid valve in communication with 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 an inlet of a fuel tank.

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

[0016] At the same time, the present invention also provides a method for linearly and continuously adjusting the fuel flow of an engine, which is special in that it includes the following steps:

[0017] 1] Build the above engine fuel flow linear continuous regulation system;

[0018] 2] Debug the system and adjust the flow rate according to the flow control valve flow adjustment range [Q min ,Q max ], calculate the control current range of the flow control 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 identification 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] According to the control current range [A min , A max ] and the number of adjustment actions X, calculate the control current interval A;

[0021] 5] Determine whether the control current interval A is greater than the current identification accuracy △A;

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

[0023] Further, step 2] is specifically as follows:

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

[0025]

[0026] Where, 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;

[0027] 2.2. Debug the engine fuel flow linear continuous regulation system to obtain the fuel flow coefficient C v Fitting curve with the control current of the flow control valve;

[0028] 2.3. According to the fitting curve, the control current range of the flow control valve [A min , A max ];

[0029] 2.4. According to the control current range [A min , A max ]Determine the flow control valve opening [K min , K max ].

[0030] Further, in step 3], the calculation of the number of adjustment actions X of the flow control valve is specifically:

[0031] According to the total test time T and the preset time interval T2, the number of adjustment actions X of the flow control valve is calculated by the following formula:

[0032]

[0033] Further, step 4] is specifically as follows:

[0034] According to the control current range [A min , A max ] and the number of adjustment actions X, the control current interval A is calculated by the following formula:

[0035]

[0036] Furthermore, in step 4], the divided control current interval A is an arithmetic division.

[0037] Beneficial effects of the present invention:

[0038] 1. The present invention provides a linear continuous regulation system for engine fuel flow, which continuously supplies gas to the fuel tank through an automatic boost module, thereby maintaining a constant pressure in the fuel tank (i.e., a constant pressure at the inlet of a flow regulating valve), and adjusting the pressure at the outlet by changing the opening of the flow regulating valve, thereby achieving linear regulation of the fuel flow.

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

[0040] 3. The present invention provides a method for linearly and continuously regulating the engine fuel flow rate. The working data of the engine at various flow rates can be obtained in one test, thereby judging the working state of the engine and further determining the lean and rich boundaries of the engine, thereby greatly improving the experimental efficiency and solving the problem of accurately obtaining the lean and rich boundaries of the engine combustion chamber in a single test.

[0041] 4. The present invention provides a method for linearly and continuously regulating the fuel flow of an engine, which can realize linearly and continuously regulating the fuel flow over a wide range within a limited test time, and the regulating range can reach 10 times. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0043] Description of reference numerals:

[0044] 1-Fuel tank, 2-Automatic boost 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] like Figure 1 As shown, a linear continuous regulation system for engine fuel flow includes 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 to an external air source, and the other end is connected to the inlet of the fuel tank 1, for pressurizing the inside of the fuel tank 1; in this embodiment, the external air source is nitrogen. When the fuel flow of the engine is lower than a certain flow value, the engine is not sufficiently powered, causing its operation to be unstable, or even to stall, and it is in a lean state at this time; when the fuel flow of the engine is higher than a certain flow value, its combustion is incomplete, causing power to drop and fuel consumption to increase, and it is in a rich state at this time.

[0046] The outlet of the fuel tank 1 is provided with an isolation valve 3, a flow meter 5, a flow regulating valve 4 and a first pneumatic valve 6 in sequence along the flow direction of the fuel; the flow meter 5 is installed on the fuel pipeline in front of the flow regulating valve 4, and can obtain the real-time flow of the fuel to ensure the accuracy of the fuel flow measurement; the first pneumatic valve 6 is used to connect with the engine through a pipeline; the second pneumatic valve 7 is provided at the inlet of the fuel tank 1 through a pipeline, and is used to release the internal pressure of the fuel tank 1 after the test; a pressure gauge 8 is provided at the air inlet of the automatic supercharging module 2, 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. A filter 9 is provided between the isolation valve 3 and the flow meter 5; the automatic supercharging 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 connected to the control module for communication, and the control module is used to control the current of the flow regulating valve 4 to change its opening to achieve linear and continuous regulation of the engine fuel flow.

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

[0048] At the same time, the present invention also provides a method for linearly and continuously adjusting the fuel flow of an engine, comprising the following steps:

[0049] 1] Build the above engine fuel flow linear continuous regulation system;

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

[0051] 2.1. According to the flow adjustment range of the flow control valve 4 [Q min ,Q max ], the fuel flow coefficient C is calculated by the following formula v Range:

[0052]

[0053] Where, Q is the fuel flow rate; G is the relative density of the fuel; ΔP is the pressure difference between the fuel tank 1 and the engine inlet;

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

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

[0056] 2.4. Since the opening of the flow control valve 4 is linearly related to the control current, according to the control current range [A min , A max ], determine the flow control valve 4 opening [K min , K max ];

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

[0058] 3] Define the response time of the flow control valve 4 as T1, the execution time as T2, and the current identification 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 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 control valve 4 is T1, and the execution time is T2, which are kept consistent within the small action range. The time interval required for the flow control valve 4 to move from the start to the full action is set as the execution time T2, and the subsequent actions of each step will maintain a continuous relay with the previous step. If the time interval of each step exceeds T2, the opening curve of the flow control valve 4 (the flow control valve 4 has different opening ranges under different control currents, which are generally 0% to 100%) will have a stable section in each step.

[0061] 4] According to the control current range [A min , A max ] and the number of adjustment actions X, the control current interval A is calculated by the following formula:

[0062]

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

[0064] Table 1

[0065] Time(s) Current (mA) Flow rate (g / s) / opening 0 <![CDATA[A min ]]> <![CDATA[Q min / K min ]]> <![CDATA[T2]]> <![CDATA[A min +A]]> … <![CDATA[2T2]]> <h2 style=";text-align:left;direction:ltr"><![CDATA[A <h2 style=";text-align:left;direction:ltr"> min <h2 style=";text-align:left;direction:ltr"> +2A]]><h2 style=";text-align:left;direction:ltr"> … <![CDATA[3T2]]> <![CDATA[A min +3A]]> … … … … <![CDATA[T-T2]]> <![CDATA[A max -A]]> … T <![CDATA[A max ]]> <![CDATA[Q max / K max ]]>

[0066] 5] Determine whether the control current interval A is greater than the current identification accuracy △A. If so, divide the control current interval A arithmetic difference to 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 control valve 4 is determined according to the total test time T and the preset time interval T2. The control current interval A is divided according to the arithmetic difference method. The control current △A is changed in each step. When A>△A, the opening change of the flow control valve 4 at the beginning of the next step will coincide with the time when the opening change of the previous step ends, ensuring that the opening of the flow control valve 4 changes linearly and realizing linear regulation of the fuel flow; when A≤△A, the flow control valve 4 does not respond in some adjustment processes, resulting in an unstable fuel flow curve, which coincides with the rich oil boundary of the engine and cannot accurately obtain the test data.

Claims

1. A linear continuous regulation system for engine fuel flow, characterized in that: It comprises a fuel tank (1), an automatic pressure-increasing 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; One end of the automatic pressurizing module (2) is connected to an external gas source, and the other end is connected to the inlet of the fuel tank (1), and is used to pressurize the interior of the fuel tank (1); The outlet of the fuel tank (1) is provided with an isolation valve (3), a flow meter (5), a flow regulating valve (4) and a first pneumatic valve (6) in sequence along the flow direction of the fuel, and the first pneumatic valve (6) is connected to the engine through a pipeline; The second pneumatic valve (7) is arranged at the inlet of the fuel tank (1) through a pipeline, and is used to release the internal pressure of the fuel tank (1) after the test is completed; Pressure gauges (8) are provided at the air inlet of the automatic boost module (2), 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 boost 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 connected to the control module for communication. The control module is used to control the current of the flow regulating valve (4) to change its opening, thereby realizing linear and continuous regulation of the engine fuel flow.

2. According to claim 1, a linear continuous regulation system for engine fuel flow, characterized in that: The automatic pressure-boosting module (2) comprises at least two pressure-stabilizing pipes connected in parallel; each pressure-stabilizing pipe is provided with a solenoid valve (21) that is in communication with the control module; One end of the pressure-stabilizing pipeline is connected to an external gas source, and the other end is connected to an inlet of a fuel tank (1).

3. According to claim 2, a linear continuous regulation system for engine fuel flow, characterized in that: It also includes a filter (9) arranged between the isolation valve (3) and the flow meter (5).

4. A method for linearly and continuously regulating the fuel flow of an engine, characterized in that: The following steps are involved: 1] Construct an engine fuel flow linear continuous regulation system as described in any one of claims 1 to 3; 2] Debug the system and adjust the flow rate of the flow control valve (4) according to the flow rate adjustment range [Q min ,Q max ], calculate the control current range of the flow control valve (4) [A min , A max ] and flow control valve (4) opening [K min , K max ]; 3] Define the response time of the flow control valve (4) as T1, the execution time as T2, and the current identification accuracy as ΔA; 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 (4) based on the total test time T and the preset time interval T2; 4] According to the control current range [A min , A max ] and the number of adjustment actions X, calculate the control current interval A; 5] Determine whether the control current interval A is greater than the current identification accuracy △A; If yes, divide the control current interval A to complete the linear and continuous regulation of the engine fuel flow; otherwise, readjust the preset time interval and return to step 3].

5. A method for linearly and continuously regulating engine fuel flow according to claim 4, characterized in that: Step 2] Specifically: 2.

1. According to the flow control range of the flow control valve (4) [Q min ,Q max ], the fuel flow coefficient C is calculated by the following formula v Range: In the formula, Q is the fuel flow rate; G is the relative density of fuel; ΔP is the pressure difference between the fuel tank (1) and the engine inlet; 2.

2. Debug the engine fuel flow linear continuous regulation system to obtain the fuel flow coefficient C v A fitting curve of the control current of the flow control valve (4); 2.

3. According to the fitting curve, the control current range of the flow control valve (4) [A min , A max ]; 2.

4. According to the control current range [A min , A max ]Determine the opening of the flow control valve (4) [K min , K max ].

6. A method for linearly and continuously regulating engine fuel flow according to claim 5, characterized in that: In step 3], the calculation of the number of adjustment actions X of the flow control valve (4) is specifically: According to the total test time T and the preset time interval T2, the number of adjustment actions X of the flow control valve (4) is calculated by the following formula:

7. A method for linearly and continuously regulating engine fuel flow according to claim 6, characterized in that: Step 4] Specifically: According to the control current range [A min , A max ] and the number of adjustment actions X, the control current interval A is calculated by the following formula:

8. The method for linearly and continuously regulating the fuel flow of an engine according to claim 7, characterized in that: In step 4], the divided control current interval A is an arithmetic division.

Images