A method and apparatus for extending pressure measurement resolution

Abstract

The application relates to the technical field of engine pressure measurement, in particular to a method and device for extending pressure measurement resolution. The device for extending pressure measurement resolution comprises an air pressure converter and a differential pressure sensor. The differential pressure sensor is arranged in a vacuum chamber. The differential pressure sensor is provided with a test shell which has a reference port and a measurement port. The reference port is communicated with the air pressure converter through a first connecting pipeline. The measurement port is adapted to be communicated with the outlet of an engine to be tested through a second connecting pipeline. The air pressure converter is communicated with the inlet of the engine to be tested. The inlet and the outlet are arranged in pipeline communication in the engine to be tested. The application provides a method and device for extending pressure measurement resolution, so as to solve the problem of poor measurement accuracy in the process of engine testing.

Description

Technical Field

[0001] This invention relates to the field of engine pressure measurement technology, and more specifically to a method and apparatus for extending pressure measurement resolution. Background Technology

[0002] A pressure sensor is a device that measures the pressure applied to an object. It has a wide range of applications, including automotive, aerospace, robotics, medical, and construction. The basic principle is based on the fact that the resistance, capacitance, and electric field of materials such as pressure-sensitive resistors, strain gauges, and piezoelectric crystals change with the applied force, converting these physical quantities into electrical signals that are output to the detection system.

[0003] In pressure measurement, a pressure sensor is typically installed at the measured location. The sensor's sensitivity refers to the degree to which its output signal changes with pressure. For various reasons, increasing the sensor's gain or constructing a larger sensor may be necessary to improve its sensitivity. In engine testing, pressure sensors are often used to measure the pressure at the inlet. The accuracy of the pressure measurement depends on the sensor's precision. Assuming a 10MPa pressure sensor with a precision of ±0.5%, the measurement error is 10MPa × ±0.5% = ±5kPa. If the pressure change is less than ±5kPa, the sensor cannot measure the pressure, indicating poor accuracy. Summary of the Invention

[0004] In view of this, the present invention provides a method and apparatus for extending the resolution of pressure measurement, in order to solve the problem that in engine testing, pressure sensors are often used to test the pressure value at the inlet, and the accuracy of pressure measurement depends on the accuracy of the sensor, resulting in poor measurement accuracy.

[0005] In a first aspect, the present invention provides an apparatus for extending the resolution of pressure measurement, comprising: Pressure transducer; A differential pressure sensor is provided, which is adapted to be installed in a vacuum chamber. The differential pressure sensor is provided with a test housing, which has a reference port and a measurement port. The reference port is connected to a pressure transducer through a first connecting pipe. The measurement port is adapted to be connected to the outlet of the engine under test through a second connecting pipe. The pressure transducer is connected to the inlet of the engine under test. The inlet and outlet are connected by pipes inside the engine under test.

[0006] In one optional embodiment, the test housing contains a voltage measuring chip and a signal conditioning circuit board, with the voltage measuring chip disposed on the signal conditioning circuit board.

[0007] In an alternative embodiment, a data acquisition unit is also included, wherein the housing has the terminal block, the terminal block is connected to the data acquisition unit via a signal cable, and the data acquisition unit collects pressure values ​​from the reference port and the measurement port.

[0008] In one alternative embodiment, a power supply is also included, which is connected to the terminal block via a power supply cable.

[0009] In one alternative implementation, a display screen is also included, which is connected to the power supply and the data acquisition unit circuitry, respectively.

[0010] In one optional embodiment, the differential pressure sensor has a range of 1 kPa to 100 kPa and an accuracy of ±1% to 10%. The pressure value at the measuring port is P0, the pressure value at the reference port is P1, and the measurement result of the differential pressure sensor is ΔP, where ΔP = P1 - P0.

[0011] In one alternative embodiment, a sealing flange is provided on the side wall of the vacuum chamber, through which the power supply cable, signal cable, and main pipeline pass respectively.

[0012] In one optional embodiment, a main pipeline is further included, which is connected to a first connecting pipeline and a second connecting pipeline, and the main pipeline is connected to a pressure transducer.

[0013] In one alternative implementation, a third connecting pipe is further included, which is connected to both the main pipe and the inlet of the engine under test.

[0014] Secondly, the present invention also provides a method for expanding the resolution of pressure measurement. In a vacuum state, when the engine to be tested is not started, the pressure values ​​of the reference port and the test port are the same; after the engine to be tested is started, the pressure difference between the reference port and the test port is measured by a differential pressure sensor to improve the measurement accuracy. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a device for extending the resolution of pressure measurement according to an embodiment of the present invention; Figure 2This is a schematic diagram of the device for extending pressure measurement resolution according to an embodiment of the present invention after removing the vacuum chamber; Figure 3 This is a schematic diagram of a differential pressure sensor according to an embodiment of the present invention; Figure 4 This is a schematic diagram showing the pressure change at the inlet of the engine under test after the start of the test for the device with extended pressure measurement resolution according to an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached drawings: 1. Differential pressure sensor; 101. Housing; 102. Measurement port; 103. Reference port; 104. Terminal block; 2. Pressure transducer; 3. Engine under test; 4. Vacuum chamber; 5. Power supply; 6. Data acquisition unit; 7. First connecting pipe; 8. Third connecting pipe; 9. Main pipe; 10. Power cable; 11. Signal cable; 12. Second connecting pipe. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The following is combined Figures 1 to 4 The following describes embodiments of the present invention.

[0020] According to an embodiment of the present invention, in one aspect, an apparatus for extending the resolution of pressure measurement is provided, comprising: a pressure transducer 2; a differential pressure sensor 1, the differential pressure sensor 1 being adapted to be disposed in a vacuum chamber, the differential pressure sensor 1 having a test housing 101, the test housing 101 having a reference port 103 and a measurement port 102, the reference port 103 being connected to the pressure transducer 2 through a first connecting pipe 7, the measurement port 102 being adapted to be connected to the outlet of an engine 3 under test through a second connecting pipe, and the pressure transducer 2 being connected to the inlet of the engine 3 under test.

[0021] In a vacuum state, when the engine to be tested is not started, the pressure values ​​of the reference port 103 and the test port are the same; after the engine to be tested is started, the pressure difference between the reference port 103 and the test port is measured by the differential pressure sensor 1 to improve the measurement accuracy.

[0022] It should be noted that the vacuum state in the vacuum chamber 4 in this embodiment is less than 100 Pa, and not an absolute vacuum state.

[0023] In one embodiment, such as Figure 1As shown, the test housing 101 contains a voltage measuring chip and a signal conditioning circuit board, with the voltage measuring chip mounted on the signal conditioning circuit board. The signal conditioning circuit board provides support and protection for the voltage measuring chip, which then analyzes and makes judgments based on the obtained data.

[0024] In one embodiment, such as Figure 1 , Figure 2 and Figure 3 As shown, the housing 101 is provided with a terminal block 104, which is connected to the data acquisition unit 6 via a signal cable 11. The data acquisition unit 6 collects the pressure values ​​of the reference port 103 and the measurement port 102 for further analysis.

[0025] In one embodiment, such as Figure 1 , Figure 2 As shown, it also includes a power supply 5, which is connected to the terminal block 104 via a power supply cable 10, and is provided with the electrical energy required for the test.

[0026] In one embodiment, a display screen is also included. The display screen is connected to the power supply 5 and the data acquisition unit 6 respectively. The display screen displays the reference data of the corresponding reference port 103 and the measurement data of the measurement port 102 to help on-site personnel monitor, record and analyze.

[0027] In one embodiment, the differential pressure sensor 1 has a range of 1 kPa to 100 kPa and an accuracy of ±1% to 10%. The pressure value of the measuring port 102 is P0, the pressure value of the reference port 103 is P1, and the measurement result of the differential pressure sensor 1 is ΔP, where ΔP = P1 - P0.

[0028] Generally, the range of differential pressure sensor 1 is relatively small, typically 1 kPa to 100 kPa. Taking a range of 10 kPa as an example, with an accuracy of ±0.5%, the measurement error is 10 kPa × ±0.5% = ±5 Pa. In this case, assuming the pressure change at the measurement location is approximately 5 MPa (i.e., the pressure difference between reference port 103 and measurement port 102), by setting P1 to 5 MPa, the pressure value at that location can be accurately calculated using P0 = P1 + ΔP. This increases the resolution of the pressure measurement and allows for the detection of minute pressure fluctuations.

[0029] In one embodiment, such as Figure 1 , Figure 2As shown, it also includes a main pipeline 9, which is connected to the first connecting pipeline 7 and the second connecting pipeline 12, and is also connected to the pressure transducer 2. The main pipeline 9 connects to the pressure transducer 2, meaning that the pressure transducer 2 outputs or extracts gas, which is then distributed by the main pipeline 9 to the first connecting pipeline 7 and the second connecting pipeline. To control the pipelines, a first on / off valve is provided on the first connecting pipeline 7, and a second on / off valve is provided on the second connecting pipeline 12. Specifically, both the first and second on / off valves are solenoid valves.

[0030] In one embodiment, such as Figure 1 , Figure 2 As shown, it also includes a third connecting pipe 8, which is connected to the main pipe 9 and the inlet of the engine under test 3, respectively, so as to connect the main pipe 9 and the inlet of the engine under test 3 through the third connecting pipe 8. To realize the control of the third connecting pipe 8, a third control valve is also provided on the third connecting pipe 8. Specifically, the third opening and closing valve is a solenoid valve. It should be noted that the first opening and closing valve, the second opening and closing valve, and the third opening and closing valve are respectively connected to the data acquisition unit 6, and the data acquisition unit 6 controls the opening and closing of the first opening and closing valve, the second opening and closing valve, and the third opening and closing valve according to a preset program.

[0031] In one embodiment, a sealing flange is provided on the side wall of the vacuum chamber 4, through which the power supply cable 10, signal cable 11, and main conduit 9 pass. The sealing flange prevents external gas from entering the power supply cable 10, signal cable 11, and main conduit 9 as they pass through the vacuum chamber 4.

[0032] In this embodiment, the differential pressure sensor 1 works by applying the measured pressure directly to the diaphragm of the sensor, causing a micro-displacement of the diaphragm proportional to the water pressure, which in turn changes the resistance or capacitance of the sensor. This change is detected by electronic circuitry and converted into a standard measurement signal corresponding to the pressure, which is then transmitted to the signal acquisition unit via signal cable 11.

[0033] According to an embodiment of the present invention, in another aspect, a method for extending the resolution of pressure measurement is also provided, comprising the following steps: 1) Before the test, the vacuum chamber is evacuated. The pressure transducer 2 is not working. The first, second and third opening and closing valves are all open until the pressure in the vacuum chamber is close to the vacuum state (less than 100Pa). During the whole process, due to the long evacuation time, the pressure of the measuring port 102 and the reference port 103 will continue to decrease and keep up with the pressure in the vacuum chamber. When the pressure in the vacuum chamber is close to the vacuum state, the evacuation operation of the vacuum chamber is stopped after the test conditions are met. The pressure values ​​of the reference port 103 and the measuring port 102 of the pressure sensor are the same. 2) Pressurize the inlet of the engine under test 3 to 6MPa. Use the pressure converter 2 as the pressurization device for the inlet of the engine under test 3. Send the pressurized gas to the first connecting pipe 7 and the second connecting pipe 12 through the main pipe 9. That is, pressurize the measuring port 102 and the reference port 103 of the differential pressure sensor 1 at the same time. At this time, the pressure of the reference port 103 and the measuring port 102 cancel each other out, the differential pressure sensor 1 has no output and the measured value is 0. 3) When the engine is started, the pressure at the inlet of the engine to be tested 3 changes. Due to the water hammer effect at the inlet, the pressure value fluctuates continuously. The fluctuating value is sensed and measured by the differential pressure sensor 1. The data acquisition unit analyzes the measured data and displays it on the screen. The entire process is carried out outside the vacuum chamber.

[0034] The device for extended pressure measurement resolution provided by this invention has the following advantages: (1) It measures the pressure at the inlet of the engine under test using a differential pressure sensor, resulting in high measurement accuracy; (2) It includes a reference port and a measurement port, such as... Figure 4 As shown, by measuring with a differential pressure sensor, the pressure value of the oscillation is monitored, and the pressure change at the measured pressure position at the inlet is accurately measured. In particular, it can capture small pressure fluctuations, increase the resolution of pressure measurement, and improve the accuracy of pressure measurement.

[0035] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A device for extending the resolution of pressure measurement, characterized in that, include: Pressure converter (2); Differential pressure sensor (1), the differential pressure sensor (1) is adapted to be installed in a vacuum chamber, the differential pressure sensor (1) is provided with a test housing (101), the test housing (101) has a reference port (103) and a measurement port (102), the reference port (103) is connected to the pressure transducer (2) through a first connecting pipe (7), the measurement port (102) is adapted to be connected to the outlet of the engine under test (3) through a second connecting pipe (12), the pressure transducer (2) is connected to the inlet of the engine under test (3), and the inlet and outlet are connected in a pipe in the engine under test (3).

2. The device for extending pressure measurement resolution according to claim 1, characterized in that, The test housing (101) is provided with a pressure measuring chip and a signal conditioning circuit board, and the pressure measuring chip is disposed on the signal conditioning circuit board.

3. The device for extending pressure measurement resolution according to claim 2, characterized in that, It also includes a data acquisition unit (6), on which a terminal block (104) is provided. The terminal block (104) is connected to the data acquisition unit (6) via a signal cable (11). The data acquisition unit (6) collects pressure values ​​from the reference port (103) and the measurement port (102).

4. The device for extending pressure measurement resolution according to claim 3, characterized in that, It also includes a power supply (5), which is connected to the terminal block (104) via a power supply cable (10).

5. The apparatus for extending pressure measurement resolution according to claim 4, characterized in that, It also includes a display screen, which is connected to the power supply (5) and the data acquisition unit (6) respectively.

6. The apparatus for extending pressure measurement resolution according to claim 5, characterized in that, The differential pressure sensor (1) has a range of 1 kPa to 100 kPa and an accuracy of ±1% to 10%. The pressure value of the measuring port (102) is P0, the pressure value of the reference port (103) is P1, and the measurement result of the differential pressure sensor (1) is ΔP, where ΔP = P1 - P0.

7. The apparatus for extending pressure measurement resolution according to claim 5, characterized in that, A sealing flange is provided on the side wall of the vacuum chamber (4), and the power supply cable (10), signal cable (11) and main pipeline (9) are respectively installed through the sealing flange.

8. The apparatus for extending pressure measurement resolution according to claim 1, characterized in that, It also includes a main pipeline (9), which is connected to the first connecting pipeline (7) and the second connecting pipeline (12) respectively, and the main pipeline (9) is connected to the air pressure converter (2).

9. The apparatus for extending pressure measurement resolution according to claim 8, characterized in that, It also includes a third connecting pipe (8), which is connected to the main pipe (9) and the inlet of the engine to be tested (3).

10. A method for extending pressure measurement resolution, used with the apparatus for extending pressure measurement resolution as described in claim 1, characterized in that, Under vacuum conditions, when the engine to be tested (3) is not started, the pressure values ​​of the reference port (103) and the test port are the same; after the engine to be tested (3) is started, the pressure difference between the reference port (103) and the test port is measured by the differential pressure sensor (1) to improve the measurement accuracy.

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