Railway vehicle air compressor and control method thereof

Abstract

This invention discloses an air compressor for rail vehicles and its control method, comprising the following steps: S1, collecting the current ambient temperature, ambient humidity, and air compressor lubricating oil temperature; S2, determining the final temperature of the air compressor lubricating oil based on the current ambient temperature, ambient humidity, air compressor lubricating oil temperature, operating time, and lubricating oil temperature curve; S3, determining whether the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature; if so, reducing the output displacement of the air compressor; if not, maintaining the current output displacement of the air compressor. Due to the adoption of the above technical solution, compared with the prior art, this invention estimates the final temperature of the air compressor lubricating oil. When the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature, it extends the operating time of the air compressor by reducing the output displacement, thereby increasing the final temperature of the air compressor lubricating oil and preventing emulsification of the lubricating oil.

Description

Technical Field

[0001] This invention relates to the field of rail transit technology, specifically to an air compressor for rail vehicles and its control method. Background Technology

[0002] An air compressor is a compressed air generating device used on rail vehicles to provide the compressed air required by ventilation equipment. Currently, rail vehicles are equipped with air compressors with fixed output displacement. However, the ventilation requirements of trains are complex and varied; air consumption differs under different operating conditions and environments. For example, in the initial stage of operation of a subway project, passenger volume is low, resulting in low air consumption. After a period of operation, passenger volume increases, leading to an increase in train air consumption.

[0003] Therefore, in order to meet the air demand of trains under extreme operating conditions and ensure safe train stopping, it is necessary to select air compressors with larger displacement. However, under normal operating conditions, the air demand of trains is usually relatively small, which leads to the air compressor's operating rate (operating rate = air compressor working time / (air compressor working time + air compressor off-duty time)) often being at a low level, thus causing the air compressor lubricating oil to easily emulsify. Summary of the Invention

[0004] This invention provides an air compressor for rail vehicles and its control method to solve the technical problem that the lubricating oil of air compressors installed on existing rail vehicles is prone to emulsification due to the frequent low operating rate.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] On the one hand, a control method for an air compressor in a rail vehicle is provided, comprising the following steps:

[0007] S1. Collect the current ambient temperature, ambient humidity, and air compressor lubricating oil temperature;

[0008] S2. Determine the final temperature of the air compressor lubricating oil based on the current ambient temperature, ambient humidity, air compressor lubricating oil temperature, working time, and lubricating oil temperature curve.

[0009] The working time is the time required for the air compressor to pump air at the current output displacement until the total air pressure reaches the target total air pressure, which is calculated based on the current total air pressure, the target total air pressure, and the rate of increase of the total air pressure.

[0010] The lubricating oil temperature curve is the curve showing the change of air compressor lubricating oil temperature with operating time under different ambient humidity conditions;

[0011] S3. Determine if the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature; if yes, reduce the output displacement of the air compressor; if no, maintain the current output displacement of the air compressor.

[0012] As air pressure increases after adiabatic compression, its pressure dew point temperature also rises. When the air compressor operates for a short time, the lubricating oil temperature is low, and the temperature of the oil-air mixture is below its pressure dew point temperature. At this time, the air undergoes a gas-liquid phase change, releasing liquid water. This released liquid water is subjected to continuous mechanical shearing in the lubricating oil, eventually leading to emulsification. As the air compressor operates for longer periods, the lubricating oil temperature gradually rises. When the temperature of the oil-air mixture exceeds its pressure dew point temperature, the water vapor in the air will not condense into water. Instead, the water vapor will enter the cooler and dryer, among other post-processing devices, with the compressed air, thus preventing lubricating oil emulsification.

[0013] This invention estimates the final temperature of the air compressor lubricating oil. When the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature, the output displacement of the air compressor is reduced to extend the working time of the air compressor, thereby increasing the final temperature of the air compressor lubricating oil and preventing emulsification of the lubricating oil.

[0014] It should be noted that the pressure dew point temperature can be obtained by referring to a table, specifically Figure A.1 of Appendix A of TB / T 2710.2, which shows the compressed air dew point temperature. The parameters required in the table can be measured using appropriate sensors, such as inlet temperature, humidity, exhaust pressure, and inlet pressure (atmospheric pressure). The air compressor can use a variable frequency motor, controlled by a frequency converter. The frequency converter controls the input frequency of the variable frequency motor based on different operating mode signals from the Train Control and Management System (TCMS) to achieve different output displacements.

[0015] In some embodiments, before step S1, the following steps are included: if the current total air pressure is lower than or equal to a first pressure threshold, the output displacement of the air compressor is set to a first output displacement; if the current total air pressure is higher than the first pressure threshold and lower than or equal to a second pressure threshold, the output displacement of the air compressor is set to a second output displacement, and step S1 is proceeded; the first output displacement is greater than the second output displacement. When the total air pressure is too low, the air is pumped at the maximum output displacement to prioritize ensuring the air demand of the train under extreme operating conditions.

[0016] On the other hand, a rail vehicle air compressor is provided, comprising:

[0017] The data acquisition unit is used to collect the current ambient temperature, ambient humidity, and air compressor lubricating oil temperature.

[0018] The data processing unit is used to determine the final temperature of the air compressor lubricating oil based on the current ambient temperature, ambient humidity, air compressor lubricating oil temperature, working time, and lubricating oil temperature curve.

[0019] The strategy unit is used to execute the first strategy;

[0020] The first strategy includes: determining whether the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature; if so, reducing the output displacement of the air compressor; if not, maintaining the current output displacement of the air compressor.

[0021] The working time is the time required for the air compressor to pump air at the current output displacement until the total air pressure reaches the target total air pressure, which is calculated based on the current total air pressure, the target total air pressure, and the rate of increase of the total air pressure.

[0022] The lubricating oil temperature curve is the curve showing the change of air compressor lubricating oil temperature with operating time under different ambient humidity conditions.

[0023] In some embodiments, the strategy unit is used to execute a second strategy when the current total air pressure is lower than or equal to a first pressure threshold; and to set the output displacement of the air compressor to a second output displacement and execute the first strategy when the current total air pressure is higher than the first pressure threshold and lower than or equal to the second pressure threshold.

[0024] The second strategy includes setting the output displacement of the air compressor to a first output displacement.

[0025] The first output displacement is greater than the second output displacement.

[0026] In another aspect, a computer device is provided, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above-described method.

[0027] In another aspect, a computer-readable storage medium is provided that stores a computer program or instructions thereon, which, when executed by a processor, implement the steps of the above-described method.

[0028] In another aspect, a computer program product is provided, including a computer program or instructions that, when executed by a processor, implement the steps of the above-described method.

[0029] This invention has at least the following technical effects or advantages:

[0030] 1. By estimating the final temperature of the air compressor lubricating oil, when the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature, the working time of the air compressor is extended by reducing the output displacement of the air compressor, thereby increasing the final temperature of the air compressor lubricating oil and preventing the lubricating oil from emulsifying.

[0031] 2. When the total air pressure is too low, the maximum output displacement will be used to ensure the air supply needs of the train under extreme conditions. Attached Figure Description

[0032] Figure 1 This is a flowchart of a control method for an air compressor in a rail vehicle according to an embodiment of the present invention.

[0033] Figure 2 This is a compressed air dew point temperature chart according to one embodiment of the present invention;

[0034] Figure 3 This is a curve showing the change in air compressor lubricating oil temperature with operating time when the ambient humidity is 70% in one embodiment of the present invention. Detailed Implementation

[0035] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0036] Example 1

[0037] See Figure 1 A control method for an air compressor in a rail vehicle includes the following steps:

[0038] If the current total air pressure P is lower than or equal to the first pressure threshold P1 (for example, it can be set to 750 kPa), the second strategy is executed; the second strategy includes: setting the output displacement of the air compressor to the first output displacement L1 (for example, it can be set to 750 L / min).

[0039] If the current total air pressure P is higher than the first pressure threshold P1 and lower than or equal to the second pressure threshold P2 (e.g., it can be set to 800 kPa), the output displacement of the air compressor is set to the second output displacement L2 (e.g., it can be set to 600 L / min), and the first strategy is executed. The first strategy includes: S1, collecting the current ambient temperature, ambient humidity, and air compressor lubricating oil temperature; S2, determining the final temperature TF of the air compressor lubricating oil based on the current ambient temperature, ambient humidity, air compressor lubricating oil temperature, working time, and lubricating oil temperature curve; S3, determining whether the final temperature TF of the air compressor lubricating oil is less than the pressure dew point temperature TL; if yes, reducing the output displacement of the air compressor; if no, maintaining the current output displacement of the air compressor.

[0040] The pressure dew point temperature can be obtained by looking up a table, such as... Figure 2As shown. The operating time is the time required for the air compressor to reach the target total air pressure P3 (e.g., 950 kPa) at its current output displacement. It can be calculated based on the current total air pressure, the target total air pressure, and the rate of increase in total air pressure. The lubricating oil temperature curve shows the change in air compressor lubricating oil temperature with operating time under different ambient humidity conditions, as shown. Figure 3 As shown. This curve can be determined based on air compressor bench tests and can be characterized by the following formula: TF = T0 + (T H - T0) * (1 - e^(-t / τ)); where T0 is the initial temperature of the lubricating oil; T H t represents the ambient temperature, i.e., the inlet temperature; t represents the operating time of the air compressor; τ represents the temperature rise constant, which can be determined experimentally. The first output displacement L1 is greater than the second output displacement L2.

[0041] Example 2

[0042] An air compressor for rail vehicles, comprising:

[0043] The data acquisition unit is used to collect the current ambient temperature, ambient humidity, and air compressor lubricating oil temperature.

[0044] The data processing unit is used to determine the final temperature of the air compressor lubricating oil based on the current ambient temperature, ambient humidity, air compressor lubricating oil temperature, operating time, and lubricating oil temperature profile; and

[0045] Strategy unit, used for:

[0046] When the current total air pressure P is lower than or equal to the first pressure threshold P1 (e.g., it can be set to 750 kPa), the second strategy is executed; the second strategy includes: setting the output displacement of the air compressor to the first output displacement L1 (e.g., it can be set to 750 L / min).

[0047] When the current total air pressure P is higher than the first pressure threshold P1 and lower than or equal to the second pressure threshold P2 (e.g., it can be set to 800 kPa), the output displacement of the air compressor is set to the second output displacement L2 (e.g., it can be set to 600 L / min) and the first strategy is executed; the first strategy includes: determining whether the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature; if yes, reducing the output displacement of the air compressor; if no, maintaining the current output displacement of the air compressor;

[0048] The pressure dew point temperature can be obtained by looking up a table, such as... Figure 2As shown. The operating time is the time required for the air compressor to reach the target total air pressure P3 (e.g., 950 kPa) at its current output displacement. It can be calculated based on the current total air pressure, the target total air pressure, and the rate of increase in total air pressure. The lubricating oil temperature curve shows the change in air compressor lubricating oil temperature with operating time under different ambient humidity conditions, as shown. Figure 3 As shown. This curve can be determined based on air compressor bench tests and can be characterized by the following formula: TF = T0 + (T H - T0) * (1 - e^(-t / τ)); where T0 is the initial temperature of the lubricating oil; T H t represents the ambient temperature, i.e., the inlet temperature; t represents the operating time of the air compressor; τ represents the temperature rise constant, which can be determined experimentally. The first output displacement is greater than the second output displacement.

[0049] The data acquisition unit specifically includes a humidity sensor, a first temperature sensor, and a second temperature sensor. The humidity sensor is located at the air compressor inlet and is used to collect ambient humidity data. The first temperature sensor is located at the air compressor inlet and is used to collect ambient temperature data. The second temperature sensor is used to collect the temperature of the air compressor lubricating oil.

[0050] Example 3

[0051] A computer device includes a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above-described method.

[0052] Example 4

[0053] A computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implement the steps of the above-described method.

[0054] Example 5

[0055] A computer program product includes a computer program or instructions that, when executed by a processor, implement the steps of the above-described method.

[0056] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0057] Similarly, it should be understood that, in order to streamline this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0058] Those skilled in the art will understand that the modules, units, or groups of devices in the examples disclosed herein can be arranged in the device as described in this embodiment, or alternatively, can be located in one or more devices different from the device in this example. The modules in the foregoing examples can be combined into a single module or, in addition, can be divided into multiple sub-modules.

[0059] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or groups in the embodiments can be combined into a single module, unit, or group, and further, they can be divided into multiple sub-modules, sub-units, or sub-groups. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0060] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments.

[0061] Furthermore, some of the embodiments described herein are methods or combinations of method elements that can be implemented by a processor of a computer system or by other means of performing the functions. Therefore, a processor having the necessary instructions for implementing the methods or method elements forms means for implementing the methods or method elements. Furthermore, the elements described herein in the apparatus embodiments are examples of means for implementing the functions performed by elements for the purposes of carrying out the invention.

[0062] The various techniques described herein can be implemented in combination with hardware or software, or a combination thereof. Thus, the methods and apparatus of the present invention, or certain aspects or portions thereof, can take the form of program code (i.e., instructions) embedded in a tangible medium, such as a floppy disk, CD-ROM, hard disk, or any other machine-readable storage medium, wherein when the program is loaded into and executed by a machine such as a computer, the machine becomes an apparatus for practicing the present invention.

[0063] When the program code is executed on a programmable computer, the computing device generally includes a processor, a processor-readable storage medium (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. The memory is configured to store program code; the processor is configured to execute the method of the present invention according to instructions in the program code stored in the memory.

[0064] By way of example, and not limitation, computer-readable media include computer storage media and communication media. Computer storage media stores information such as computer-readable instructions, data structures, program modules, or other data. Communication media generally embodies computer-readable instructions, data structures, program modules, or other data in the form of modulated data signals such as carrier waves or other transmission mechanisms, and includes any information delivery medium. Any combination of the above is also included within the scope of computer-readable media.

[0065] As used herein, unless otherwise specified, the use of ordinal numbers such as “first,” “second,” “third,” etc., to describe ordinary objects merely indicates different instances of similar objects and is not intended to imply that the objects being described must have a given order in time, space, ordering, or any other manner.

[0066] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

[0067] Finally, it should be noted that this invention does not explain in detail the common knowledge recognized by those skilled in the art. The above description is only a specific embodiment of this invention and is not intended to limit this invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A control method for an air compressor in a rail vehicle, characterized in that, Includes the following steps: S1. Collect the current ambient temperature, ambient humidity, and air compressor lubricating oil temperature; S2. Determine the final temperature of the air compressor lubricating oil based on the current ambient temperature, ambient humidity, air compressor lubricating oil temperature, working time, and lubricating oil temperature curve. The working time is the time required for the air compressor to pump air at the current output displacement until the total air pressure reaches the target total air pressure, which is calculated based on the current total air pressure, the target total air pressure, and the rate of increase of the total air pressure. The lubricating oil temperature curve is the curve showing the change of air compressor lubricating oil temperature with operating time under different ambient humidity conditions; S3. Determine if the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature; if yes, reduce the output displacement of the air compressor; if no, maintain the current output displacement of the air compressor.

2. The control method for a rail vehicle air compressor according to claim 1, characterized in that, Before step S1, the following steps are included: if the current total air pressure is lower than or equal to the first pressure threshold, the output displacement of the air compressor is set to the first output displacement; if the current total air pressure is higher than the first pressure threshold and lower than or equal to the second pressure threshold, the output displacement of the air compressor is set to the second output displacement, and step S1 is entered; the first output displacement is greater than the second output displacement.

3. An air compressor for rail vehicles, characterized in that, include: The data acquisition unit is used to collect the current ambient temperature, ambient humidity, and air compressor lubricating oil temperature. The data processing unit is used to determine the final temperature of the air compressor lubricating oil based on the current ambient temperature, ambient humidity, air compressor lubricating oil temperature, working time, and lubricating oil temperature curve. The strategy unit is used to execute the first strategy; The first strategy includes: determining whether the final temperature of the air compressor lubricating oil is lower than the pressure dew point temperature; if so, reducing the output displacement of the air compressor; if not, maintaining the current output displacement of the air compressor. The working time is the time required for the air compressor to pump air at the current output displacement until the total air pressure reaches the target total air pressure, which is calculated based on the current total air pressure, the target total air pressure, and the rate of increase of the total air pressure. The lubricating oil temperature curve is the curve showing the change of air compressor lubricating oil temperature with operating time under different ambient humidity conditions.

4. The air compressor for rail vehicles according to claim 3, characterized in that: The strategy unit is used to execute the second strategy when the current total air pressure is lower than or equal to the first pressure threshold; when the current total air pressure is higher than the first pressure threshold but lower than or equal to the second pressure threshold, the output displacement of the air compressor is set to the second output displacement and the first strategy is executed. The second strategy includes setting the output displacement of the air compressor to a first output displacement. The first output displacement is greater than the second output displacement.

5. A computer device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method of claim 1 or 2.

6. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method described in claim 1 or 2.

7. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method described in claim 1 or 2.

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