A control method and control system for an air compressor, and a locomotive.

Abstract

This invention discloses a control method and control system for an air compressor, as well as a locomotive. The control method includes: acquiring the total air cylinder pressure value P generated by a pressure transmitter; calculating a first pressure drop rate k of the total air cylinder pressure value P within a first preset time when P ≥ y; where y is a preset maximum pressure limit value; controlling the operating mode of the power switch and the unloading valve according to the first pressure drop rate k, a preset shutdown threshold a, and a preset air charging rate L; the operating mode includes a coasting mode, in which the power switch is on and the unloading valve is closed. This invention avoids frequent start-up and shutdown of the air compressor, reduces the time consumption of shutdown and start-up, thereby improving air charging efficiency. It also helps to improve the stability of the input power supply voltage, extend the service life and operational reliability of the inverter and air compressor unit, and reduce the total life cycle cost.

Description

Technical Field

[0001] This invention relates to the field of air compressor technology, and more particularly to a control method and control system for an air compressor, and a locomotive. Background Technology

[0002] Air compressors for railway locomotives are the core power source for the air braking system of railway locomotives and rolling stock, providing compressed air. Currently, conventional air compressor control methods mainly include automatic mode and forced-pump mode. In automatic mode, the air compressor starts and stops automatically based on the main air reservoir pressure. It starts when the main air reservoir pressure is lower than the set start pressure and stops when the set stop pressure is reached. In forced-pump mode, the air compressor switch is set to the "forced pump" position, and the air compressor runs continuously, unaffected by the main air reservoir pressure. When the main air reservoir pressure is too high, the high-pressure safety valve activates and continuously discharges air.

[0003] However, in practical applications, when a locomotive is coupled to a train and the train is being charged with air, or when the train is descending a long slope or there is a leak in the pipeline, the pressure in the main air reservoir drops rapidly, causing the air compressor to start and stop frequently. A complete working cycle of an air compressor includes a starting phase, a charging phase, and a coasting phase. After completing these three phases, the air compressor stops and waits for the next working command. The starting and coasting phases account for a significant portion of the time, and the stopping phase itself does not produce compressed air. Therefore, frequent starts and stops mean that a large amount of time is wasted on non-charging phases, severely reducing the charging efficiency of the braking system. At the same time, frequent starts and stops also cause frequent fluctuations in the input power supply voltage, thereby shortening the service life of the inverter and air compressor unit.

[0004] Faced with the above operating conditions, although the driver can manually switch to the strong pump mode to keep the air compressor running continuously to avoid frequent start-stop, in the strong pump mode, the high-pressure safety valve frequently operates and continuously discharges air, causing large fluctuations in the total air pressure; at the same time, the air compressor runs continuously for a long time, resulting in additional power consumption, which is not conducive to energy conservation and emission reduction.

[0005] Therefore, existing technologies suffer from problems such as low air charging efficiency, shortened equipment lifespan, and severe power fluctuations due to frequent start-stop of the air compressor in automatic mode, and significant pressure fluctuations and additional power consumption due to frequent venting of the high-pressure safety valve in forced pump mode. Summary of the Invention

[0006] This invention provides a control method and control system for an air compressor, as well as a locomotive, which avoids frequent starts and stops of the air compressor, reduces the time consumed during startup and shutdown, improves air charging efficiency, and enhances the stability of the input power supply voltage.

[0007] In a first aspect, the present invention provides a control method for an air compressor, which is executed by a control system of the air compressor. The control system includes: an air compressor, a pressure transmitter, a main air cylinder, an unloading valve, and a power switch; the air compressor is electrically connected to the power switch, the air outlet of the air compressor is connected to the main air cylinder through an air circuit, and the air inlet of the air compressor is connected to the atmosphere through the unloading valve; the pressure transmitter is connected to the main air cylinder through an air circuit. The control method includes: Obtain the total air cylinder pressure value P generated by the pressure transmitter; When P≥y, calculate the first pressure drop rate k of the total air cylinder pressure value P within a first preset time; where y is the preset maximum pressure limit value. The operating modes of the power switch and the unloading valve are controlled according to the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L; the operating modes include a coasting mode, in which the power switch is turned on and the unloading valve is turned off.

[0008] Optionally, the operating modes of the power switch and the unloading valve are controlled according to the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L, including: When k≥a, calculate the second pressure drop rate k' of the total air cylinder pressure value P within the second preset time period; The operating modes of the power switch and the unloading valve are controlled according to the second pressure drop rate k' and the preset air charging rate L.

[0009] Optionally, the operating modes of the power switch and the unloading valve are controlled according to the second pressure drop rate k' and the preset air charging rate L, including: When k'≥L, the power switch and the unloading valve are controlled to be in the air charging mode; in the air charging mode, both the power switch and the unloading valve are open; When a < k' < L, the power switch and the unloading valve are controlled to be in coasting mode.

[0010] Optionally, controlling the operating mode of the power switch and the unloading valve based on the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L further includes: When k < a, the power switch and the unloading valve are controlled to be in shutdown mode; in shutdown mode, both the power switch and the unloading valve are closed.

[0011] Optionally, after obtaining the total cylinder pressure value P generated by the pressure transmitter, the method further includes: When P≤x, the power switch and the unloading valve are controlled to be in the air charging mode; in the air charging mode, both the power switch and the unloading valve are open; where x is a preset minimum pressure limit value; Where x < y.

[0012] Optionally, when P≤x, controlling the power switch and the unloading valve to be in air-charging mode includes: When P ≤ x, the power switch is turned on. Obtain the real-time rotational speed of the air compressor; When the real-time rotational speed is greater than or equal to the preset rated rotational speed, the unloading valve is controlled to open.

[0013] Optionally, after obtaining the total cylinder pressure value P generated by the pressure transmitter, the method further includes: When x < P < y, the operating mode of the power switch and the unloading valve remains unchanged.

[0014] In a second aspect, the present invention also provides a control system for an air compressor, for executing a control method for an air compressor as described in any of the first aspects, the control system comprising: an air compressor, a pressure transmitter, an on-board microcomputer, a main air cylinder, an unloading valve, and a power switch; The air compressor is electrically connected to the power switch, the air outlet of the air compressor is connected to the main air cylinder through an air circuit, and the air inlet of the air compressor is connected to the atmosphere through the unloading valve. The pressure transmitter is connected to the main air cylinder air passage and is used to detect the gas pressure of the main air cylinder and generate the main air cylinder pressure value P. The on-board microcomputer is electrically connected to the power switch, the unloading valve, and the pressure transmitter, respectively, and is used to calculate the first pressure drop rate k of the total air cylinder pressure value P within a first preset time when P≥y; and control the working mode of the power switch and the unloading valve according to the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L; the working mode includes a coasting mode, in which the power switch is turned on and the unloading valve is closed; where y is a preset maximum pressure limit value.

[0015] Optionally, the on-board microcomputer is further used for: When P≤x, the power switch and the unloading valve are controlled to be in the air charging mode; in the air charging mode, both the power switch and the unloading valve are open; where x is a preset minimum pressure limit value; x<y; When x < P < y, the operating mode of the power switch and the unloading valve remains unchanged.

[0016] Thirdly, the present invention also provides a locomotive including a control system for an air compressor as described in any of the second aspects.

[0017] The air compressor control method, control system, and locomotive provided by this invention acquire the total air cylinder pressure value generated by the pressure transmitter, and calculate the first pressure drop rate of the total air cylinder pressure value within a first preset time when the total air cylinder pressure value is greater than or equal to a preset maximum limit pressure value. Then, based on the first pressure drop rate, a preset shutdown threshold, and a preset air charging rate, the speed at which the total air cylinder pressure value drops is determined, and the operating mode of the power switch and unloading valve is controlled accordingly. This makes the operating mode of the power switch and unloading valve more consistent with the changing trend of the total air cylinder pressure value, thereby avoiding frequent start-up and shutdown of the air compressor, reducing the time consumption of shutdown and start-up, improving air charging efficiency, and also helping to improve the stability of the input power supply voltage, extend the service life and operational reliability of the inverter and air compressor unit, and reduce the total life cycle cost.

[0018] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a control system for an air compressor provided in an embodiment of the present invention; Figure 2 A flowchart illustrating a control method for an air compressor provided in an embodiment of the present invention; Figure 3 A flowchart illustrating another air compressor control method provided in an embodiment of the present invention; Figure 4 A flowchart illustrating another air compressor control method provided in an embodiment of the present invention; Figure 5 This is a flowchart illustrating another air compressor control method provided in an embodiment of the present invention. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0022] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "on" or "below" another element, it can be formed not only directly on or below the other element, but also indirectly on or below it through intermediate elements. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] The term "comprising" and its variations as used in this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0024] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0025] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0026] Figure 1 This is a schematic diagram of the structure of a control system for an air compressor provided in an embodiment of the present invention, as shown below. Figure 1As shown, the control system includes an air compressor 1, a pressure transmitter 2, an on-board microcomputer 3, a main air cylinder 4, an unloading valve 5, and a power switch 6. The air compressor 1 is electrically connected to the power switch 6, the air outlet of the air compressor 1 is connected to the main air cylinder 4 through an air circuit, and the air inlet of the air compressor 1 is connected to the atmosphere through the unloading valve 5. The pressure transmitter 2 is connected to the main air cylinder 4 through an air circuit and is used to detect the gas pressure of the main air cylinder 4 and generate a main air cylinder pressure value P. The on-board microcomputer 3 is electrically connected to the power switch 6, the unloading valve 5, and the pressure transmitter 2, respectively, and is used to calculate the first pressure drop rate k of the main air cylinder pressure value P within a first preset time when P≥y. Based on the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L, the microcomputer 3 controls the working mode of the power switch 6 and the unloading valve 5. The working mode includes a coasting mode, in which the power switch 6 is turned on and the unloading valve 5 is closed. Here, y is a preset maximum pressure limit value.

[0027] Specifically, in a locomotive, the air compressor 1 is typically used to compress atmospheric air into high-pressure air and store it in the main air reservoir 4, thereby providing stable and reliable compressed air for the locomotive and its traction train's braking, suspension, and pneumatic equipment. (Reference) Figure 1 The control system of the air compressor includes an air compressor 1, a pressure transmitter 2, an on-board microcomputer 3, a main air reservoir 4, an unloading valve 5, and a power switch 6. The air compressor 1 is electrically connected to the power switch 6, which controls the operation of the air compressor 1. When the power switch 6 is turned on, the air compressor 1 starts to operate and compresses atmospheric air into high-pressure air. When the power switch 6 is turned off, the air compressor stops operating and does not compress the atmospheric air. For example, the power switch 6 can be an air compressor inverter, a constant-pressure constant-frequency AC air compressor contactor, or a DC air compressor contactor.

[0028] Further, refer to Figure 1 The air compressor 1's inlet is connected to the atmosphere via an unloading valve 5, and its outlet is connected to the main air cylinder 4 via an air passage. When the unloading valve 5 is open, air can enter the air compressor 1 through it. At this time, when the power switch 6 is on, the air compressor 1 is in charging mode, compressing the atmosphere into high-pressure air and inputting it into the main air cylinder 4. However, when the unloading valve 5 is closed, it blocks the air from entering the air compressor 1. At this time, even if the power switch 6 is on, the air compressor 1 cannot compress the atmosphere, and it is in coasting mode. When both the power switch 6 and the unloading valve 5 are closed, the air compressor 1 is in shutdown mode.

[0029] Further, refer to Figure 1The pressure transmitter 2 is connected to the air circuit of the main air cylinder 4 to detect the gas pressure of the main air cylinder 4 and generate the main air cylinder pressure value P. The on-board microcomputer 3 is electrically connected to the power switch 6, the unloading valve 5 and the pressure transmitter 2 respectively. It can control the working mode of the power switch 6 and the unloading valve 5 according to the main air cylinder pressure value P, thereby realizing the regulation of the air pressure in the main air cylinder 4.

[0030] Specifically, when P ≥ y, that is, when the pressure value P of the main air cylinder is greater than or equal to the preset maximum limit pressure value y, it indicates that the pressure in the main air cylinder 4 has reached the set upper limit threshold. At this time, the air compressor 1 should be controlled to stop charging high-pressure air into the main air cylinder 4. This can be achieved by controlling only the unloading valve 5 to close, or by simultaneously closing the unloading valve 5 and the power switch 6. It is understandable that after simultaneously closing the unloading valve 5 and the power switch 6, the air compressor 1 will be in a shutdown mode. If the air compressor 1 is then put back into the air charging mode in a short period of time, it will frequently experience non-air charging cycles such as starting, coasting, and stopping, resulting in a significant reduction in air charging efficiency. This will also cause frequent fluctuations in the power supply voltage, accelerating the aging of the inverter and the air compressor unit.

[0031] Therefore, when P≥y, the first pressure drop rate k of the total air cylinder pressure value P within the first preset time is calculated. Then, based on the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L, the rate at which the total air cylinder pressure value P in the total air cylinder 4 drops is determined, that is, whether the air compressor 1 needs to be restarted in a short time is determined. This determines the working mode of the power switch 6 and the unloading valve 5, that is, whether the air compressor 1 stops charging high-pressure air into the total air cylinder 4 by closing only the unloading valve 5, or by closing both the unloading valve 5 and the power switch 6 at the same time.

[0032] When only the unloading valve 5 is closed, that is, when the power switch 6 is on and the unloading valve 5 is closed, the power switch 6 and the unloading valve 5 are in coasting mode. In this mode, if the air compressor 1 needs to charge the main air cylinder 4 for a short period of time, the time consumption of shutdown and start-up can be avoided, thereby improving the charging efficiency. At the same time, it also helps to improve the stability of the input power supply voltage, extend the service life and operational reliability of the inverter and air compressor unit, and reduce the total life cycle cost.

[0033] This invention uses a pressure transmitter to detect the total air cylinder pressure. When the total air cylinder pressure is greater than or equal to a preset maximum pressure limit, it calculates the first pressure drop rate of the total air cylinder pressure within a first preset time. Based on the first pressure drop rate, a preset shutdown threshold, and a preset charging rate, it determines the rate of pressure drop in the total air cylinder and controls the operating modes of the power switch and unloading valve. This ensures that the operating modes of the power switch and unloading valve better match the changing trend of the total air cylinder pressure, thereby avoiding frequent starts and stops of the air compressor, reducing start-up and shutdown time, improving charging efficiency, and also helping to improve the stability of the input power supply voltage, extending the service life and reliability of the inverter and air compressor unit, and reducing the total life cycle cost.

[0034] Optionally, the on-board microcomputer is also used to: control the power switch 6 and the unloading valve 5 to be in the air charging mode when P≤x; in the air charging mode, both the power switch 6 and the unloading valve 5 are open; where x is the preset minimum pressure limit value; x<y; when x<P<y, the operating mode of the power switch 6 and the unloading valve 5 remains unchanged.

[0035] Specifically, when P≤x, that is, when the pressure value P of the main air cylinder is less than or equal to the preset minimum limit pressure value x, it indicates that the pressure in the main air cylinder 4 has reached the set lower limit threshold. At this time, the air compressor 1 should be controlled to charge high-pressure air into the main air cylinder 4. Therefore, the power switch 6 and the unloading valve 5 are controlled to be in the air charging mode, that is, both the power switch 6 and the unloading valve 5 are opened. Atmosphere enters the air compressor 1 through the unloading valve 5. Under the action of the power switch 6, the air compressor 1 converts the atmosphere into high-pressure air and inputs it into the main air cylinder 4.

[0036] Furthermore, when x < P < y, if the total air cylinder pressure value P is within the range of the preset minimum limit pressure value x and the preset maximum limit pressure value y, it indicates that the pressure in the total air cylinder 4 is within the preset standard range. At this time, it is sufficient to keep the working mode of the power switch 6 and the unloading valve 5 unchanged.

[0037] This invention improves the stability of the pressure in the main air cylinder and enhances the locomotive's operating performance by limiting the pressure in the main air cylinder to a preset minimum and maximum pressure range, and by controlling the power switch and unloading valve to operate in different modes when the pressure in the main air cylinder exceeds this range.

[0038] Based on the same inventive concept, embodiments of the present invention also provide a control method for an air compressor, which is executed using any of the above-described air compressor control systems. Figure 2 This is a flowchart illustrating a control method for an air compressor provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the control method includes: S101. Obtain the total air cylinder pressure value P generated by the pressure transmitter.

[0039] Specifically, refer to Figure 1 The control system of the air compressor includes an air compressor 1, a pressure transmitter 2, an on-board microcomputer 3, a main air cylinder 4, an unloading valve 5, and a power switch 6. The air compressor 1 is electrically connected to the power switch 6. The power switch 6 is used to control the operation of the air compressor 1. When the power switch 6 is turned on, the air compressor 1 starts to run and can compress the atmosphere into high-pressure air. When the power switch 6 is turned off, the air compressor stops running and does not compress the atmosphere.

[0040] Further reference Figure 1 The air compressor 1's inlet is connected to the atmosphere via an unloading valve 5, and its outlet is connected to the main air cylinder 4 via an air passage. When the unloading valve 5 is open, air can enter the air compressor 1 through it. At this time, when the power switch 6 is on, the air compressor 1 is in charging mode, compressing the atmosphere into high-pressure air and inputting it into the main air cylinder 4. However, when the unloading valve 5 is closed, it blocks the air from entering the air compressor 1. At this time, even if the power switch 6 is on, the air compressor 1 cannot compress the atmosphere, and it is in coasting mode. When both the power switch 6 and the unloading valve 5 are closed, the air compressor 1 is in shutdown mode.

[0041] Further reference Figure 1 Pressure transmitter 2 is connected to the air passage of main air reservoir 4 and is used to detect the gas pressure in main air reservoir 4, generating a main air reservoir pressure value P. Therefore, by obtaining the main air reservoir pressure value P generated by pressure transmitter 2, it can be determined whether high-pressure air needs to be supplied to main air reservoir 4.

[0042] S102. When P≥y, calculate the first pressure drop rate k of the total air cylinder pressure value P within the first preset time.

[0043] Specifically, when P ≥ y, that is, when the total air cylinder pressure P is greater than or equal to the preset maximum limit pressure value y, it indicates that the pressure in the total air cylinder 4 has reached the set upper limit threshold. At this time, the air compressor 1 should be controlled to stop charging high-pressure air into the total air cylinder 4. This can be achieved by controlling only the unloading valve 5 to close, or by simultaneously closing the unloading valve 5 and the power switch 6. It is understood that after simultaneously closing the unloading valve 5 and the power switch 6, the air compressor 1 will be in a shutdown mode. If the air compressor 1 is then put back into the air charging mode within a short period, it will frequently experience non-air charging cycles such as starting, coasting, and stopping, leading to a significant reduction in air charging efficiency and frequent fluctuations in power supply voltage, thus accelerating the aging of the inverter and air compressor unit. Here, y is the preset maximum limit pressure value. Therefore, when P ≥ y, the first pressure drop rate k of the total air cylinder pressure value P within the first preset time is calculated to determine the rate of decrease of the total air cylinder pressure value P within the first preset time.

[0044] S103. Control the working mode of the power switch and the unloading valve according to the first pressure drop rate k, the preset shutdown threshold a and the preset air charging rate L.

[0045] Specifically, based on the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L, the rate at which the pressure value P in the main air cylinder 4 drops can be determined, i.e., whether the air compressor 1 needs to be restarted in a short period of time. This determines the operating mode of the power switch 6 and the unloading valve 5, i.e., whether the air compressor 1 stops charging high-pressure air into the main air cylinder 4 by closing only the unloading valve 5, or by closing both the unloading valve 5 and the power switch 6 simultaneously.

[0046] When only the unloading valve 5 is closed, that is, when the power switch 6 is on and the unloading valve 5 is closed, the power switch 6 and the unloading valve 5 are in coasting mode. In this mode, if the air compressor 1 needs to charge the main air cylinder 4 for a short period of time, the time consumption of shutdown and start-up can be avoided, thereby improving the charging efficiency. At the same time, it also helps to improve the stability of the input power supply voltage, extend the service life and operational reliability of the inverter and air compressor unit, and reduce the total life cycle cost.

[0047] This invention acquires the total air cylinder pressure value generated by a pressure transmitter. When the total air cylinder pressure value is greater than or equal to a preset maximum limit pressure value, it calculates the first pressure drop rate of the total air cylinder pressure value within a first preset time period. Then, based on the first pressure drop rate, a preset shutdown threshold, and a preset charging rate, it determines the rate of decrease of the total air cylinder pressure value and controls the operating mode of the power switch and unloading valve. This makes the operating mode of the power switch and unloading valve more compatible with the changing trend of the total air cylinder pressure value, thereby avoiding frequent start-up and shutdown of the air compressor, reducing the time consumption of shutdown and start-up, improving charging efficiency, and also helping to improve the stability of the input power supply voltage, extend the service life and operational reliability of the inverter and air compressor unit, and reduce the total life cycle cost.

[0048] Optionally, Figure 3 This is a flowchart illustrating another air compressor control method provided by an embodiment of the present invention. This embodiment is a refinement of the above embodiment. Specifically, for step S103, controlling the working mode of the power switch and the unloading valve according to the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L, it can be further refined as follows: When k≥a, calculate the second pressure drop rate k' of the total air cylinder pressure value P within the second preset time. The operating modes of the power switch and the unloading valve are controlled according to the second pressure drop rate k' and the preset air charging rate L. Furthermore, step S103, controlling the operating mode of the power switch and unloading valve based on the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L, can be further refined as follows: When k < a, the control power switch and unloading valve are in shutdown mode.

[0049] For parts not described in detail in this embodiment, please refer to the foregoing embodiments, such as... Figure 3 As shown, the control method provided in this embodiment includes: S201. Obtain the total cylinder pressure value P generated by the pressure transmitter. S202. When P≥y, calculate the first pressure drop rate k of the total air cylinder pressure value P within the first preset time.

[0050] S203. When k≥a, calculate the second pressure drop rate k' of the total air cylinder pressure value P within the second preset time.

[0051] Specifically, after calculating the first pressure drop rate k of the total air cylinder pressure value P within the first preset time, the rate of pressure drop in the total air cylinder 4 can be determined by comparing the first pressure drop rate k with the preset shutdown threshold a. The preset shutdown threshold a can be obtained based on the brake system configuration and operational tests. When k ≥ a, that is, when the first pressure drop rate k of the total air cylinder pressure value P is greater than or equal to the preset shutdown threshold a, it indicates that the pressure drop rate in the total air cylinder 4 is relatively fast, and air compressor 1 may need to fill the total air cylinder 4 with air in a short time. Therefore, at this time, power switch 6 and unloading valve 5 cannot be closed, and further judgment is needed on the pressure drop rate in the total air cylinder 4.

[0052] Furthermore, since the pressure in the main air cylinder 4 drops rapidly when k≥a, the second pressure drop rate k' of the main air cylinder pressure value P within the second preset time can be calculated after k≥a is determined. Then, the working mode of the power switch 6 and the unloading valve 5 can be determined by using the second pressure drop rate k'. By calculating the pressure drop rate in the main air cylinder 4 in real time, the accuracy of the working mode control of the power switch 6 and the unloading valve 5 can be improved, and the problem of control lag can be avoided.

[0053] S204. Control the working mode of the power switch and the unloading valve according to the second pressure drop rate k' and the preset air charging rate L.

[0054] Specifically, after calculating the second pressure drop rate k' of the total air cylinder pressure value P within the second preset time, the operating modes of the power switch 6 and the unloading valve 5 can be controlled according to the second pressure drop rate k' and the preset charging rate L. This allows the operating modes of the power switch 6 and the unloading valve 5 to more accurately meet the changing trend of the pressure value in the total air cylinder 4, avoiding an excessively rapid drop in air pressure in the total air cylinder 4 due to an excessively large second pressure drop rate k', which would prevent the gas stored in the total air cylinder 4 from failing to meet application requirements. The preset charging rate L can be determined based on the air compressor's displacement and quantity. For a given air compressor control system, the air compressor has a defined charging rate.

[0055] S205. When k < a, the control power switch and unloading valve are in shutdown mode.

[0056] Specifically, when k < a, that is, when the first pressure drop rate k of the total air cylinder pressure value P is less than the preset shutdown threshold a, it indicates that the pressure drop rate in the total air cylinder 4 is slow, and it may not be necessary for the air compressor 1 to fill the total air cylinder 4 with air for a long time. Therefore, at this time, the power switch 6 and the unloading valve 5 can be controlled to be in shutdown mode. In shutdown mode, both the power switch 6 and the unloading valve 5 are closed, which can avoid additional power consumption and achieve the purpose of energy saving and emission reduction.

[0057] In this embodiment of the invention, when the total air cylinder pressure value is greater than or equal to a preset maximum limit pressure value, the relationship between the first pressure drop rate of the total air cylinder pressure value within a first preset time period and a preset shutdown threshold is further compared, thereby determining the speed of the pressure drop rate in the total air cylinder, and thereby controlling the working mode of the power switch and the unloading valve so that the working mode of the power switch and the unloading valve can conform to the changing trend of the pressure in the total air cylinder.

[0058] Optionally, Figure 4 This is a flowchart illustrating another air compressor control method provided by an embodiment of the present invention. This embodiment is a refinement of the above embodiment. Specifically, for step S204, controlling the working mode of the power switch and the unloading valve according to the second pressure drop rate k' and the preset air charging rate L, it can be further refined as follows: When k'≥L, the control power switch and unloading valve are in air charging mode.

[0059] When a < k' < L, the control power switch and unloading valve are in coasting mode.

[0060] For parts not described in detail in this embodiment, please refer to the foregoing embodiments, such as... Figure 4 As shown, the control method provided in this embodiment includes: S301. Obtain the total air cylinder pressure value P generated by the pressure transmitter.

[0061] S302. When P≥y, calculate the first pressure drop rate k of the total air cylinder pressure value P within the first preset time.

[0062] S303. When k≥a, calculate the second pressure drop rate k' of the total air cylinder pressure value P within the second preset time.

[0063] S304. When k'≥L, the control power switch and unloading valve are in the air charging mode.

[0064] Specifically, after calculating the second pressure drop rate k' of the total air cylinder pressure value P within the second preset time, the relationship between the gas discharge rate and the filling rate in the total air cylinder 4 can be determined by comparing the second pressure drop rate k' with the preset air filling rate L. When k' ≥ L, that is, when the second pressure drop rate k' is greater than or equal to the preset air filling rate L, it indicates that the gas discharge rate in the total air cylinder 4 is greater than the filling rate. At this time, the control power switch 6 and the unloading valve 5 are in the air filling mode. In the air filling mode, both the power switch 6 and the unloading valve 5 are open. At this time, the atmosphere will enter the air compressor 1 through the unloading valve 5. The air compressor 1 further compresses the atmosphere into high-pressure gas and fills it into the total air cylinder 4. In this way, before the total air cylinder pressure value P of the total air cylinder 4 drops to the preset minimum pressure limit value x, the gas in the total air cylinder 4 is replenished in time, thereby avoiding the problem of low pressure due to the gas discharge rate being greater than the filling rate, which would affect the gas supply to the total air cylinder 4. This improves the stability of the total air cylinder pressure and enhances the locomotive's operating performance.

[0065] S305. When a < k' < L, the control power switch and unloading valve are in coasting mode.

[0066] Specifically, when a < k' < L, that is, when the second pressure drop rate k' is greater than the preset shutdown rate a and less than the preset air charging rate L, it indicates that the pressure drop rate in the main air cylinder 4 is between the shutdown mode and the air charging mode. At this time, the control power switch 6 and the unloading valve 5 are in coasting mode. In coasting mode, the power switch 6 is open and the unloading valve 5 is closed. At this time, the air compressor 1 does not charge gas into the main air cylinder 4, so the gas pressure in the main air cylinder 4 will continue to drop. When the total air cylinder pressure P in the main air cylinder 4 drops to the preset minimum limit pressure value x, the control power switch 6 and the unloading valve 5 can be put into the air charging mode. In the air charging mode, both the power switch 6 and the unloading valve 5 are open. At this time, since the second pressure drop rate k' is less than the preset air charging rate L, the total air cylinder pressure P in the main air cylinder 4 will quickly meet the demand and reach the preset maximum limit pressure value y. This avoids the time wasted due to frequent start-stop of the air compressor, improves air charging efficiency, and avoids the use of the forced pump mode, thereby reducing additional power consumption and achieving the goal of energy conservation and emission reduction.

[0067] S306. When k < a, the control power switch and unloading valve are in shutdown mode.

[0068] This invention compares the second pressure drop rate with a preset charging rate. When the second pressure drop rate is greater than or equal to the preset charging rate, the power switch and unloading valve are in charging mode. This avoids the problem of low pressure affecting the main air cylinder supply caused by the gas discharge rate exceeding the charging rate, thus improving the stability of the main air cylinder pressure and enhancing locomotive performance. When the second pressure drop rate is less than the preset charging rate, the power switch and unloading valve are in coasting mode. This avoids the time consumption caused by frequent start-stop of the air compressor, improving charging efficiency, and avoids the use of the forced pump mode, thereby reducing additional power consumption and achieving energy saving and emission reduction.

[0069] Optionally, Figure 5 This is a flowchart illustrating another air compressor control method provided by an embodiment of the present invention. This embodiment is a refinement of the above embodiment. Specifically, after step S301, obtaining the total air cylinder pressure value P generated by the pressure transmitter, the method further includes: When P≤x, the control power switch and unloading valve are in air charging mode.

[0070] Furthermore, after obtaining the total cylinder pressure value P generated by the pressure transmitter in step S301, the method further includes: When x < P < y, the operating mode of the control power switch and the unloading valve remains unchanged.

[0071] For parts not described in detail in this embodiment, please refer to the foregoing embodiments, such as... Figure 5 As shown, the control method provided in this embodiment includes: S401. Obtain the total air cylinder pressure value P generated by the pressure transmitter.

[0072] S402. When P≤x, the control power switch and unloading valve are in air charging mode.

[0073] Specifically, when P≤x, that is, when the pressure value P of the main air cylinder is less than or equal to the preset minimum limit pressure value x, it indicates that the pressure in the main air cylinder 4 has reached the set lower limit threshold. At this time, the air compressor 1 should be controlled to charge high-pressure air into the main air cylinder 4. Therefore, the power switch 6 and the unloading valve 5 are controlled to be in the air charging mode, that is, both the power switch 6 and the unloading valve 5 are opened. Atmosphere enters the air compressor 1 through the unloading valve 5. Under the action of the power switch 6, the air compressor 1 converts the atmosphere into high-pressure air and inputs it into the main air cylinder 4.

[0074] S403. When x < P < y, the operating mode of the control power switch and the unloading valve remains unchanged.

[0075] Specifically, when x < P < y, if the pressure value P of the main air cylinder is within the range of the preset minimum limit pressure value x and the preset maximum limit pressure value y, it indicates that the pressure in the main air cylinder 4 is within the preset standard range. At this time, it is only necessary to keep the working mode of the power switch 6 and the unloading valve 5 unchanged.

[0076] S404. When P≥y, calculate the first pressure drop rate k of the total air cylinder pressure value P within the first preset time.

[0077] S405. When k≥a, calculate the second pressure drop rate k' of the total air cylinder pressure value P within the second preset time.

[0078] S406. When k'≥L, the control power switch and unloading valve are in the air charging mode.

[0079] S407. When a < k' < L, the control power switch and unloading valve are in coasting mode.

[0080] S408. When k < a, the control power switch and unloading valve are in shutdown mode.

[0081] This invention improves the stability of the pressure in the main air cylinder and enhances the locomotive's operating performance by limiting the pressure in the main air cylinder to a preset minimum and maximum pressure range, and controlling the power switch 6 and the unloading valve 5 to operate in different modes when the pressure in the main air cylinder exceeds this range.

[0082] Based on the above embodiments, the present invention proposes variant embodiments of the above embodiments. It should be noted that, in order to keep the description brief, only the differences from the above embodiments are described in the variant embodiments.

[0083] Furthermore, since the starting current of power switch 6 is relatively large when it switches from off to on, in this embodiment, for step S402, when P≤x, controlling the power switch and unloading valve to be in air charging mode can be further refined as follows: S4021. When P≤x, control the power switch to turn on.

[0084] S4022, Obtain the real-time speed of the air compressor.

[0085] S4023. When the real-time speed is greater than or equal to the preset rated speed, control the unloading valve to open.

[0086] Specifically, for steps S4021 to S4023, when P ≤ x, i.e., when the total air cylinder pressure P is less than or equal to the preset minimum limit pressure value x, it indicates that the pressure in the total air cylinder 4 has reached the set lower threshold. At this time, the air compressor 1 should be controlled to charge compressed air into the total air cylinder 4. First, the power switch 6 is turned on to start the air compressor 1. After the air compressor 1 starts rotating, the real-time speed of the air compressor 1 is acquired. When the real-time speed is greater than or equal to the preset rated speed, it indicates that the air compressor 1 has completed the start-up and entered a stable operating state. At this time, the unloading valve 5 is then opened. This effectively avoids mechanical shock and motor overcurrent caused by low-speed loading during the start-up process, improving the reliability and charging efficiency of the system.

[0087] This invention also provides a locomotive that includes a control system for an air compressor as described in any of the preceding embodiments.

[0088] Therefore, the locomotive provided in this embodiment has the structure and operation of the air compressor control system of the above embodiment, and can achieve the effect of the air compressor control method of the above embodiment. The similarities can be referred to the above description, and will not be repeated here.

[0089] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A control method for an air compressor, characterized in that, The system is executed using an air compressor control system, which includes an air compressor, a pressure transmitter, a main air reservoir, an unloading valve, and a power switch. The air compressor is electrically connected to the power switch, the air outlet of the air compressor is connected to the main air reservoir via an air circuit, and the air inlet of the air compressor is connected to the atmosphere via the unloading valve. The pressure transmitter is connected to the main air reservoir via an air circuit. The control method includes: Obtain the total air cylinder pressure value P generated by the pressure transmitter; When P≥y, calculate the first pressure drop rate k of the total air cylinder pressure value P within a first preset time; where y is the preset maximum pressure limit value. The operating modes of the power switch and the unloading valve are controlled according to the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L; the operating modes include a coasting mode, in which the power switch is turned on and the unloading valve is turned off.

2. The control method according to claim 1, characterized in that, Based on the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L, the operating modes of the power switch and the unloading valve are controlled, including: When k≥a, calculate the second pressure drop rate k' of the total air cylinder pressure value P within the second preset time period; The operating modes of the power switch and the unloading valve are controlled according to the second pressure drop rate k' and the preset air charging rate L.

3. The control method according to claim 2, characterized in that, Based on the second pressure drop rate k' and the preset air charging rate L, the operating modes of the power switch and the unloading valve are controlled, including: When k'≥L, the power switch and the unloading valve are controlled to be in the air charging mode; in the air charging mode, both the power switch and the unloading valve are open; When a < k' < L, the power switch and the unloading valve are controlled to be in coasting mode.

4. The control method according to claim 1, characterized in that, Based on the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L, the operating modes of the power switch and the unloading valve are controlled, and the following further includes: When k < a, the power switch and the unloading valve are controlled to be in shutdown mode; in shutdown mode, both the power switch and the unloading valve are closed.

5. The control method according to claim 1, characterized in that, After obtaining the total air cylinder pressure value P generated by the pressure transmitter, the method further includes: When P≤x, the power switch and the unloading valve are controlled to be in the air charging mode; in the air charging mode, both the power switch and the unloading valve are open; where x is a preset minimum pressure limit value; Where x < y.

6. The control method according to claim 5, characterized in that, When P≤x, controlling the power switch and the unloading valve to be in air charging mode includes: When P ≤ x, the power switch is turned on. Obtain the real-time rotational speed of the air compressor; When the real-time rotational speed is greater than or equal to the preset rated rotational speed, the unloading valve is controlled to open.

7. The control method according to claim 1, characterized in that, After obtaining the total air cylinder pressure value P generated by the pressure transmitter, the method further includes: When x < P < y, the operating mode of the power switch and the unloading valve remains unchanged.

8. A control system for an air compressor, characterized in that, For performing a control method for an air compressor as described in any one of claims 1-7, the control system includes: an air compressor, a pressure transmitter, an on-board microcomputer, a main air cylinder, an unloading valve, and a power switch; The air compressor is electrically connected to the power switch, the air outlet of the air compressor is connected to the main air cylinder through an air circuit, and the air inlet of the air compressor is connected to the atmosphere through the unloading valve. The pressure transmitter is connected to the main air cylinder air passage and is used to detect the gas pressure of the main air cylinder and generate the main air cylinder pressure value P. The on-board microcomputer is electrically connected to the power switch, the unloading valve, and the pressure transmitter, respectively, and is used to calculate the first pressure drop rate k of the total air cylinder pressure value P within a first preset time when P≥y; and control the working mode of the power switch and the unloading valve according to the first pressure drop rate k, the preset shutdown threshold a, and the preset air charging rate L; the working mode includes a coasting mode, in which the power switch is turned on and the unloading valve is closed; where y is a preset maximum pressure limit value.

9. The control system according to claim 8, characterized in that, The on-board microcomputer is also used for: When P≤x, the power switch and the unloading valve are controlled to be in the air charging mode; in the air charging mode, both the power switch and the unloading valve are open; where x is a preset minimum pressure limit value; x<y; When x < P < y, the operating mode of the power switch and the unloading valve remains unchanged.

10. A locomotive, characterized in that, Includes a control system for an air compressor as described in any one of claims 8 and 9.

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