Hydraulic brake cylinder pressure control system and its control method

Abstract

This application relates to a hydraulic brake cylinder pressure control system and its control method. The control system includes a pressure generation module and a pressure control module. The pressure generation module includes a check valve, an external accumulator, and an accumulator sensor. The check valve is connected to an oil tank. The pressure control module includes a proportional solenoid valve connected to the external accumulator and the brake cylinder; a pressure-holding solenoid valve located at the overflow port of the proportional solenoid valve, which is connected to the oil tank via the pressure-holding solenoid valve; a brake cylinder sensor collecting and outputting the brake cylinder pressure; and a brake cylinder pressure switch electrically connected to the brake cylinder sensor. During the relief condition, the proportional solenoid valve is de-energized and the pressure-holding solenoid valve is energized. During coasting or braking conditions, the proportional solenoid valve is energized, and the pressure-holding solenoid valve is de-energized after a delay. This application reduces the usage rate of the proportional solenoid valve and improves system reliability through the coordinated control of the proportional solenoid valve and the pressure-holding solenoid valve.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rail vehicle braking technology, in particular to a hydraulic brake cylinder pressure control system applied to a low-floor modern tram hydraulic braking system and a control method thereof. BACKGROUND

[0002] Low-floor modern tram is one of the most advanced urban transportation systems in the world today, which adopts advanced technologies such as pantograph-free current collection and super capacitor, and has a floor distance of only 35 cm from the rail surface, without the need for a platform, and the maximum capacity is 6 to 8 times that of a bus. At present, low-floor modern trams mostly adopt hydraulic braking systems, and the existing brake control is realized by controlling the current of the proportional electromagnetic valve in the hydraulic braking system to realize braking and relief, but the proportional electromagnetic valve is in the state of being powered on for adjustment under various working conditions. Since the valve components are powered on for a long time, it has a significant impact on the service life and failure rate of the valve, and thus reduces the system availability and the operation efficiency of the vehicle.

[0003] At present, there is no effective solution to the fault risk of the proportional electromagnetic valve being powered on for adjustment and the resulting braking system failure and low reliability in the related art. SUMMARY

[0004] Embodiments of the present application provide a hydraulic brake cylinder pressure control system and a control method thereof to at least solve the fault risk of the proportional electromagnetic valve being powered on for adjustment in the related art, so as to improve the system reliability.

[0005] In a first aspect, embodiments of the present application provide a hydraulic brake cylinder pressure control system, which comprises a pressure generation module and a pressure control module. The pressure generation module comprises a one-way valve, an external accumulator and an accumulator sensor. Specifically, the one-way valve is connected with an oil tank. The pressure control module comprises:

[0006] a proportional electromagnetic valve YV1 connected with the external accumulator and a brake cylinder;

[0007] a pressure maintaining electromagnetic valve YV2 arranged at an overflow port of the proportional electromagnetic valve YV1, wherein the overflow port of the proportional electromagnetic valve YV1 is connected to the oil tank through the pressure maintaining electromagnetic valve YV2;

[0008] a brake cylinder sensor for collecting brake cylinder pressure output to the brake cylinder;

[0009] a brake cylinder pressure switch electrically connected with the brake cylinder sensor;

[0010] In the control system, when in a relief working condition, the proportional electromagnetic valve YV1 is configured to be in a power-off state, and the pressure maintaining electromagnetic valve YV2 is configured to be in a power-on state.

[0011] When the control system switches from a easing condition to a coasting condition or a braking condition, it controls the proportional solenoid valve YV1 to switch to an energized state, and after a preset time period, the pressure-holding solenoid valve YV2 switches to a de-energized state. Specifically, the preset time period includes the easing response time t_r, the coasting response time t_z, and the braking response time t_b, which are used to represent the step response time of the proportional solenoid valve YV1 to achieve the corresponding control target value under the easing condition, coasting condition, and braking condition, respectively. All of these can be set based on the test results of the rail vehicle.

[0012] With the above structure, the hydraulic brake cylinder pressure control system of this application embodiment sets a pressure-holding solenoid valve YV2 at the overflow port of the proportional valve, and uses the pressure-holding solenoid valve YV2 in conjunction with the proportional solenoid valve YV1 to control the pressure. In the relief condition, the proportional solenoid valve YV1 is controlled to be de-energized and have no pressure output, while the pressure-holding solenoid valve YV2 is controlled to be energized so that the brake cylinder still has the relief pressure required for the relief condition. When the relief condition is switched to the coasting condition or the braking condition, the proportional solenoid valve YV1 is controlled to be energized to provide a preset pressure output, while the pressure-holding solenoid valve YV2 is controlled to be de-energized for a delay, so as to ensure that the brake cylinder pressure does not drop when the condition is switched. At the same time, the switching control of the proportional solenoid valve YV1 and the pressure-holding solenoid valve YV2 under different conditions also improves the response performance of the control system.

[0013] In some embodiments, the control system is pre-configured with proportional solenoid valve fault conditions and / or pressure holding solenoid valve fault conditions. If the proportional solenoid valve YV1 and / or the pressure holding solenoid valve YV2 meet the conditions, fault diagnosis is performed on the proportional solenoid valve YV1 and / or the pressure holding solenoid valve YV2.

[0014] In some embodiments, the fault condition of the proportional solenoid valve is configured as follows: the pressure holding solenoid valve YV2 is de-energized, and the absolute value of the difference between the control target pressure value P and the brake cylinder pressure is greater than the first fault threshold △P1.

[0015] In some embodiments, the fault condition of the pressure-holding solenoid valve is configured as follows: the pressure-holding solenoid valve YV2 is energized, and after the preset time period, the absolute value of the difference between the pressure value of the accumulator and the pressure of the brake cylinder is greater than the second fault threshold △P2.

[0016] In some embodiments, the pressure control module further includes a dust filter disposed between the proportional solenoid valve YV1 and the brake cylinder.

[0017] In some embodiments, the hydraulic brake cylinder pressure control system of this application embodiment is further provided with a current detection circuit, which is electrically connected to the proportional solenoid valve, for acquiring the current acquisition value of the proportional solenoid valve YV1 in real time after the system is turned on, so that the control system can calculate the resistance value and the number of actuations of the proportional solenoid valve YV1 based on the current acquisition value.

[0018] In a second aspect, embodiments of this application provide a hydraulic brake cylinder pressure control method for controlling the hydraulic brake cylinder pressure control system described in the first aspect above, comprising:

[0019] In the pressure control step, it is determined whether the proportional solenoid valve YV1 is faulty and whether the control target pressure value P is greater than the relief condition control target value P_m1. The relief condition control target value P_m1 is calculated based on the relief condition. If so, the pressure holding solenoid valve YV2 is configured to be energized and the proportional solenoid valve YV1 is configured to be de-energized, and the control target pressure value P is set to 0. Otherwise, if the proportional solenoid valve YV1 is not faulty or the control target pressure value P ≤ the relief condition control target value P_m1, pressure control is performed according to the current operating condition of the rail vehicle.

[0020] The pressure control condition judgment step involves determining whether the current operating condition is a traction condition and whether the target control pressure value P is greater than the relief condition control target value P_m1. If so, it further determines whether the actual brake cylinder pressure P_c is greater than a preset target value b. Otherwise, it configures the proportional solenoid valve YV1 to be energized and configures the target control pressure value P to a non-relief condition control target value P_m1' before performing coasting condition pressure control or braking condition pressure control. The preset target value b is a value close to the relief condition control target value P_m1.

[0021] In some embodiments, the pressure control condition determination step further includes:

[0022] In the pressure relief control step, if the actual brake cylinder pressure P_c is determined to be greater than the preset target value b, then after a delay of the relief response time t_r, the pressure holding solenoid valve YV2 is configured to be energized and the proportional solenoid valve YV1 is configured to be de-energized, and the control target pressure value P is configured to be 0. At this time, the brake cylinder pressure in this embodiment is the pressure value at port S shown in the figure; otherwise, the pressure holding solenoid valve YV2 is configured to remain de-energized and the proportional solenoid valve YV1 is configured to remain energized, and the control target pressure value P is configured to remain at the relief working condition control target value P_m1.

[0023] In some embodiments, the pressure control condition determination step further includes:

[0024] The coasting condition pressure judgment step is as follows: if the current condition is coasting and the speed V of the rail vehicle is greater than a preset speed threshold V_r, then the condition pressure relief control step is executed; otherwise, coasting condition pressure control is performed. The preset speed threshold V_r is configured to be greater than the speed value during electro-hydraulic conversion.

[0025] In the coasting condition pressure control step, it is determined whether the pressure-holding solenoid valve YV2 is energized. If the pressure-holding solenoid valve YV2 is energized, the proportional solenoid valve YV1 is energized, the target control pressure value P is set to the coasting condition control target value P_m2, and after a delay of the coasting response time t_z, the pressure-holding solenoid valve YV2 is de-energized. At this time, the target control pressure value P reaches the coasting condition control target value P_m2. Otherwise, the proportional solenoid valve YV1 is energized, and the target control pressure value P is set to the coasting condition control target value P_m2.

[0026] In some embodiments, the pressure control condition determination step further includes:

[0027] In the braking condition pressure control step, if the current operating condition is braking, it is determined whether the pressure-holding solenoid valve YV2 is energized. If so, the proportional solenoid valve YV1 is energized and the target pressure value P is set to the braking condition control target value P_m3. After a braking response time t_b, the pressure-holding solenoid valve YV2 is de-energized. At this time, the target pressure value P reaches the braking condition control target value P_m3. Otherwise, the proportional solenoid valve YV1 is energized and the target pressure value P is set to the braking condition control target value P_m3.

[0028] Based on the above steps, the control method of this application improves the service life of the proportional solenoid valve YV1 by controlling the energization and de-energization of the proportional solenoid valve YV1 and the pressure holding solenoid valve YV2 under conditions such as braking, releasing and coasting.

[0029] In some embodiments, the method further includes:

[0030] In the fault redundancy control procedure, under traction conditions, if the proportional solenoid valve YV1 malfunctions, the pressure-holding solenoid valve YV2 is not malfunctioning, and the target control pressure value P is greater than the target control value P_m1 for the relief condition, then the pressure-holding solenoid valve YV2 is energized, the proportional solenoid valve YV1 is de-energized, and the target control pressure value P is set to 0. If the pressure-holding solenoid valve YV2 malfunctions, the proportional solenoid valve YV1 is not malfunctioning, and the pressure-holding solenoid valve YV2 is energized, then the pressure-holding solenoid valve YV2 is de-energized, the proportional solenoid valve YV1 is energized, and the target control pressure value P is set to the target control value P_m1 for the relief condition.

[0031] Based on the above steps, when either the proportional solenoid valve YV1 or the pressure-holding solenoid valve YV2 fails, the control method of this application embodiment can achieve mutual takeover guidance between the two, thereby improving the availability of the system.

[0032] Compared to related technologies, the hydraulic brake cylinder pressure control method and control method provided in this application reduce the usage rate of the proportional solenoid valve by coordinating the proportional solenoid valve and the pressure holding solenoid valve under different working conditions within the system; at the same time, the fault diagnosis algorithm of the proportional solenoid valve and the pressure holding solenoid valve is used to perform mutual fault diagnosis, and when one valve fails, the other valve takes over the brake cylinder pressure control for fault guidance, thereby improving system availability.

[0033] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0034] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0035] Figure 1 This is a schematic diagram of the hydraulic brake cylinder pressure control system according to an embodiment of this application;

[0036] Figure 2 This is a schematic diagram of the current detection circuit according to an embodiment of this application;

[0037] Figure 3 This is a flowchart of a hydraulic brake cylinder pressure control method according to an embodiment of this application;

[0038] Figure 4 This is another flowchart of a hydraulic brake cylinder pressure control method according to an embodiment of this application;

[0039] Figure 5 This is a flowchart of a hydraulic brake cylinder pressure control method according to a preferred embodiment of this application. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0041] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0042] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0043] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0044] Hydraulic braking is an application of fluid transmission that uses hydraulic oil as the pressure transmission medium. A low-power DC motor drives a hydraulic pump to pressurize the hydraulic oil and store it in an accumulator, serving as the hydraulic braking pressure source. An electrical control unit controls a hydraulic control unit, which consists of a DC motor and a series of pressure regulating valves. Based on braking command requirements under different operating conditions, the hydraulic control unit controls the output pressure of the brake calipers to brake or release the vehicle.

[0045] Hydraulic braking mainly consists of an electrical control system, a hydraulic control system, and a basic braking unit. The electrical control system receives braking commands from the train control unit. Based on different braking functions, it controls the motors and hydraulic valves in the hydraulic control system, and also communicates with the train bus to report real-time braking status and fault diagnosis information. The hydraulic control system integrates the motor, hydraulic pump, and various hydraulic valves onto a manifold block, responsible for pressure build-up, unloading, and regulation, realizing electro-hydraulic conversion; it is a key component of the hydraulic braking system. The basic braking unit converts direct hydraulic pressure or spring force overcoming hydraulic pressure into clamping force applied to the brake disc, thus braking the train.

[0046] The hydraulic control system comprises two main functional modules: a pressure generation module and a pressure control module. The pressure generation module mainly consists of a motor, a hydraulic pump, and an external accumulator, while the pressure control module primarily consists of a proportional solenoid valve and is equipped with a pressure sensor to provide feedback on the output pressure. Current technology involves adjusting the control current of the proportional solenoid valve to output hydraulic fluid from the accumulator to the hydraulic control system outlet. This keeps the proportional solenoid valve in a constantly energized regulating state, reducing its lifespan and increasing the failure rate.

[0047] To address the aforementioned technical problems, this application provides a hydraulic brake cylinder pressure control system. Figure 1 This is a schematic diagram of the hydraulic brake cylinder pressure control system according to an embodiment of this application, with reference to... Figure 1 As shown, the control system includes a pressure generation module and a pressure control module. The pressure generation module includes a one-way valve, an external accumulator, and an accumulator sensor BS. Specifically, the one-way valve is connected to an oil tank. The pressure control module includes a proportional solenoid valve YV1, a pressure holding solenoid valve YV2, a brake cylinder sensor BP, and a brake cylinder pressure switch B1. The brake cylinder sensor BP is used to collect the brake cylinder pressure output to the brake cylinder. The brake cylinder pressure switch B1 is electrically connected to the brake cylinder sensor BP to control the brake cylinder pressure.

[0048] The proportional solenoid valve YV1 is connected to an external accumulator at port S in the diagram. YV1 is also connected to a brake cylinder at port P in the diagram. A dust filter F2 is installed between YV1 and the brake cylinder. A pressure-holding solenoid valve YV2 is located at the overflow port of YV1, and the overflow port of YV1 is connected to the oil tank via YV2.

[0049] When the control system is in the relief mode, the proportional solenoid valve YV1 is configured to be de-energized and the pressure holding solenoid valve YV2 is configured to be energized. When the control system switches from the relief mode to the coasting mode or the braking mode, the proportional solenoid valve YV1 is switched to the energized state, and after a preset time period, the pressure holding solenoid valve YV2 is switched to the de-energized state. Specifically, the preset time period includes the relief response time t_r, the coasting response time t_z, and the braking response time t_b, which are used to represent the step response time of the proportional solenoid valve YV1 to achieve the corresponding control target value under the relief mode, the coasting mode, and the braking mode, respectively. All of these can be set based on the test results of the rail vehicle.

[0050] With the above structure, the hydraulic brake cylinder pressure control system of this application embodiment sets a pressure-holding solenoid valve YV2 at the overflow port of the proportional valve, and uses the pressure-holding solenoid valve YV2 in conjunction with the proportional solenoid valve YV1 to control the pressure. In the relief condition, the proportional solenoid valve YV1 is controlled to be de-energized and have no pressure output, while the pressure-holding solenoid valve YV2 is controlled to be energized so that the brake cylinder still has the relief pressure required for the relief condition. When the relief condition is switched to the coasting condition or the braking condition, the proportional solenoid valve YV1 is controlled to be energized to provide a preset pressure output, while the pressure-holding solenoid valve YV2 is controlled to be de-energized for a delay, so as to ensure that the brake cylinder pressure does not drop when the condition is switched. At the same time, the switching control of the proportional solenoid valve YV1 and the pressure-holding solenoid valve YV2 under different conditions also improves the response performance of the control system.

[0051] In some embodiments, the control system is pre-configured with proportional solenoid valve fault conditions and / or pressure-holding solenoid valve fault conditions. If the proportional solenoid valve YV1 and / or the pressure-holding solenoid valve YV2 meet the conditions, fault diagnosis is performed on the proportional solenoid valve YV1 and / or the pressure-holding solenoid valve YV2. The proportional solenoid valve fault condition is determined when the pressure-holding solenoid valve YV2 is de-energized. The system then compares the difference between the brake cylinder pressure at port P and the preset control target pressure value P, as shown in the real-time data collected by the system, with the adjustment accuracy parameter settings of the proportional solenoid valve YV1. Specifically:

[0052] The fault condition configuration for the proportional solenoid valve is as follows: the pressure-holding solenoid valve YV2 is de-energized, and the absolute value of the difference between the control target pressure value P and the brake cylinder pressure is greater than the first fault threshold △P1. With the proportional solenoid valve YV1 and the pressure-holding solenoid valve YV2 selected, their adjustment accuracy parameters are known and will not be elaborated upon here.

[0053] The fault condition for the pressure-holding solenoid valve is set by the system judging the following time and pressure difference between the brake cylinder pressure at port P and the accumulator pressure at port S in real time when the pressure-holding solenoid valve YV2 is energized. The fault condition for the pressure-holding solenoid valve is configured as follows: the pressure-holding solenoid valve YV2 is energized, and after the preset time period, the absolute value of the difference between the pressure value of the accumulator and the pressure of the brake cylinder is greater than the second fault threshold △P2.

[0054] Based on the above structure, this application embodiment configures a fault diagnosis strategy for the proportional solenoid valve and the pressure holding solenoid valve to achieve mutual fault diagnosis between the two. In the case of a fault in one valve, the other valve can be used to guide the pressure control of the brake cylinder to improve system availability.

[0055] In some embodiments, to further improve the reliability of the system, the hydraulic brake cylinder pressure control system of this application embodiment is further provided with a current detection circuit, electrically connected to the proportional solenoid valve, such as... Figure 2 As shown, it is used to acquire the current acquisition value of the proportional solenoid valve YV1 in real time after the system is powered on, so that the control system can calculate the resistance value and the number of actuations of the proportional solenoid valve YV1 based on the current acquisition value.

[0056] refer to Figure 2 As shown, the current detection circuit in this embodiment specifically includes: diode D1, resistor Ri, inductive load Load, and current shunt monitor I3. Diode D1 is electrically connected to the proportional solenoid valve to collect the current of the proportional solenoid valve driven by the PWM pulse. The inductive load Load is connected in parallel across diode D1. Resistor Ri is connected in series between the negative terminal of diode D1 and the inductive load Load. Current shunt monitor I3 is connected in parallel across resistor Ri.

[0057] The aforementioned resistance value is obtained under relaxed operating conditions by acquiring the real-time control output duty cycle D of the proportional solenoid valve YV1. Based on the rated operating voltage U and the current acquisition value I of the proportional solenoid valve YV1, the resistance value R of the proportional solenoid valve YV1 is calculated in real time as R = (D × U) / I. When the control output duty cycle D is greater than a set minimum duty cycle D_int, the number of times the proportional solenoid valve YV1 operates is counted. This resistance value and the number of operations are used to fit the technical parameters of the proportional solenoid valve YV1 and then output a fault warning message for the proportional solenoid valve YV1.

[0058] Based on the above structure, the control system of this application embodiment monitors the number of actuations and resistance value of the proportional solenoid valve in real time, and provides early warning prompts to the proportional solenoid valve based on the monitoring results, thereby further improving the system reliability.

[0059] This embodiment also provides a method for controlling the pressure of a hydraulic brake cylinder. Figure 3 This is a flowchart of a hydraulic brake cylinder pressure control method according to an embodiment of this application, such as... Figure 3 As shown, the process includes the following steps:

[0060] In pressure control step S1, after the system is powered on, fault diagnosis is performed on the proportional solenoid valve YV1 and the pressure holding solenoid valve YV2 to determine whether the proportional solenoid valve YV1 is faulty and whether the control target pressure value P is greater than the relief condition control target value P_m1. The relief condition control target value P_m1 is calculated based on the relief condition. If so, the pressure holding solenoid valve YV2 is configured to be energized and the proportional solenoid valve YV1 is configured to be de-energized, and the control target pressure value P is set to 0. Thus, the pressure holding solenoid valve YV2 is used to ensure that the brake cylinder still has pressure output even when the proportional solenoid valve YV1 is de-energized and has no pressure output. Otherwise, if the proportional solenoid valve YV1 is not faulty or the control target pressure value P ≤ the relief condition control target value P_m1, pressure control is performed according to the current working condition of the rail vehicle.

[0061] In pressure control condition judgment step S2, it is determined whether the current operating condition is a traction condition and whether the control target pressure value P is greater than the relief condition control target value P_m1. If so, the relief condition condition is met. Further, it is determined whether the actual brake cylinder pressure P_c is greater than a preset target value b, and relief condition pressure control is performed. Otherwise, the proportional solenoid valve YV1 is energized, and the control target pressure value P is configured as a non-relief condition control target value P_m1', and coasting condition pressure control or braking condition pressure control is performed. The preset target value b is a value close to the relief condition control target value P_m1.

[0062] In some embodiments, the pressure control condition determination step S2 further includes:

[0063] In step S21 of the pressure relief control, if it is determined that the actual brake cylinder pressure P_c is greater than the preset target value b, then after a delay of the relief response time t_r, the pressure holding solenoid valve YV2 is configured to be energized and the proportional solenoid valve YV1 is configured to be de-energized, and the control target pressure value P is configured to be 0. This ensures that the actual brake cylinder pressure P_c can be maintained at a value greater than the preset target value b for a longer time than the relief response time t_r. This achieves that even when the proportional solenoid valve YV1 is de-energized in the vehicle relief state, the brake cylinder still outputs pressure, reducing the usage rate of the proportional solenoid valve YV1. In this case, the brake cylinder pressure in the embodiment is the pressure value at port S shown in the figure. Otherwise, the pressure holding solenoid valve YV2 is configured to remain de-energized and the proportional solenoid valve YV1 is configured to remain energized, and the control target pressure value P is configured to remain at the relief working condition control target value P_m1.

[0064] In some embodiments, the pressure control condition determination step S2 further includes:

[0065] In the coasting condition pressure judgment step S221, if the current condition is coasting condition and the speed V of the rail vehicle is greater than a preset speed threshold V_r, then the pressure relief control step is executed; otherwise, coasting condition pressure control is performed. The preset speed threshold V_r is configured to be greater than the speed value when the electro-hydraulic conversion condition is in progress.

[0066] In the coasting condition pressure control step S222, it is determined whether the pressure-holding solenoid valve YV2 is energized. If the pressure-holding solenoid valve YV2 is energized, the proportional solenoid valve YV1 is energized, the target control pressure value P is set to the coasting condition control target value P_m2, and after a delay of the coasting response time t_z, the pressure-holding solenoid valve YV2 is de-energized. At this time, the target control pressure value P reaches the coasting condition control target value P_m2. Otherwise, the proportional solenoid valve YV1 is energized and the target control pressure value P is set to the coasting condition control target value P_m2.

[0067] In some embodiments, the pressure control condition determination step S2 further includes:

[0068] In braking condition pressure control step S23, if the current operating condition is braking condition, determine whether the pressure-holding solenoid valve YV2 is energized. If so, configure the proportional solenoid valve YV1 to be energized and configure the control target pressure value P as the braking condition control target value P_m3. After a delay of the braking response time t_b, configure the pressure-holding solenoid valve YV2 to be de-energized. At this time, the control target pressure value P reaches the braking condition control target value P_m3. Otherwise, configure the proportional solenoid valve YV1 to be energized and configure the control target pressure value P as the braking condition control target value P_m3.

[0069] Based on the above steps, the control method of this application improves the service life of the proportional solenoid valve YV1 by controlling the energization and de-energization of the proportional solenoid valve YV1 and the pressure holding solenoid valve YV2 under conditions such as braking, releasing and coasting.

[0070] In some embodiments, reference Figure 4 As shown, the method also includes:

[0071] In the fault redundancy control step S4, under traction conditions, if the proportional solenoid valve YV1 is faulty, the pressure-holding solenoid valve YV2 is not faulty, and the control target pressure value P is greater than the relief condition control target value P_m1, then the pressure-holding solenoid valve YV2 is energized, the proportional solenoid valve YV1 is de-energized, and the control target pressure value P is set to 0; if the pressure-holding solenoid valve YV2 is faulty, the proportional solenoid valve YV1 is not faulty, and the pressure-holding solenoid valve YV2 is energized, then the pressure-holding solenoid valve YV2 is de-energized, the proportional solenoid valve YV1 is energized, and the control target pressure value P is set to the relief condition control target value P_m1.

[0072] Based on the above steps, when either the proportional solenoid valve YV1 or the pressure-holding solenoid valve YV2 fails, the control method of this application embodiment can achieve mutual takeover guidance between the two, thereby improving the availability of the system.

[0073] The embodiments of this application will be described and illustrated below through preferred embodiments.

[0074] Figure 5 This is a flowchart of a hydraulic brake cylinder pressure control method according to a preferred embodiment of this application. Figure 5 As shown, the control method includes the following steps:

[0075] Step S501: Determine if there is a fault and the target pressure value P > P_m1; if so, control the pressure holding solenoid valve YV2 to be energized and the proportional solenoid valve YV1 to be de-energized, and control the target pressure value P = 0; otherwise, that is, the solenoid valve is not faulty or P ≤ P_m1, proceed to the following working conditions for further judgment.

[0076] Step S502: Determine whether it is a traction condition and whether the target pressure value P > P_m1. If yes, proceed to step S503. Otherwise, energize the proportional solenoid valve YV1, P = P_m1', and proceed to step S504 or step S506.

[0077] Step S503: Determine whether P_c>b. If yes, after a delay time t_r, control the pressure holding solenoid valve YV2 to be energized and the proportional solenoid valve YV1 to be de-energized, changing the final control target pressure value of the system to P=0; otherwise, control the pressure holding solenoid valve YV2 to remain de-energized and the proportional solenoid valve YV1 to remain energized, and P=P_m1.

[0078] Step S504: Determine whether the vehicle is in a non-traction, non-braking condition and the vehicle speed V > V_r. If yes, return to step S502; otherwise, proceed to step S505.

[0079] Step S505: Determine whether the pressure-holding solenoid valve YV2 is energized. If so, control the proportional solenoid valve YV1 to be energized and control P = P_m2. After a delay of t_z, control the pressure-holding solenoid valve YV2 to be de-energized. Otherwise, control the proportional solenoid valve YV1 to be energized and control P = P_m2.

[0080] Step S506: Under braking conditions, determine whether the pressure holding solenoid valve YV2 is energized. If so, control the proportional solenoid valve YV1 to be energized and control P = P_m3. After a delay of t_b, control the pressure holding solenoid valve YV2 to be de-energized. Otherwise, control the proportional solenoid valve YV1 to be energized and control P = P_m3.

[0081] Step S507: Determine whether the pressure holding solenoid valve YV2 is faulty. If so, de-energize the pressure holding solenoid valve YV2 and energize the proportional solenoid valve YV1, and set the control target pressure value to the control target value under the corresponding working condition; otherwise, maintain the output of step S503 or S506.

[0082] Based on the above steps, this application utilizes the relationship between the target control pressure value and the actual pressure, and dynamically changes the target control pressure value by setting the delayed energization and delayed de-energization conditions of the pressure-holding solenoid valve YV2. This improves the system's rapid and effective control response, and ensures that even when the proportional solenoid valve YV1 is de-energized in the vehicle's release state, the brake cylinder still outputs pressure, thereby reducing the usage rate of the proportional solenoid valve YV1.

[0083] It should be noted that the steps shown in the above flowchart or the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here. For example, the fault redundancy control step S4 may be executed cyclically during the operation of the control system of this application.

[0084] Based on the above, this application embodiment reduces the usage rate of the proportional solenoid valve by coordinating the proportional solenoid valve and the pressure-holding solenoid valve under different operating conditions within the system; at the same time, it uses the fault diagnosis algorithm of the proportional solenoid valve and the pressure-holding solenoid valve to perform mutual fault diagnosis, so that when one valve fails, the other valve controls the pressure control of the brake cylinder to guide the fault and improve system availability; in addition, the system monitors the number of actuations and resistance value of the proportional solenoid valve in real time, and provides early warning prompts for the proportional solenoid valve based on the monitoring results, further improving system reliability.

[0085] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A hydraulic brake cylinder pressure control system characterized by, The control system comprises a pressure generating module and a pressure control module, the pressure generating module comprises a one-way valve, an external accumulator and an accumulator sensor, the one-way valve is connected with an oil tank, the pressure control module comprises: a proportional electromagnetic valve connected with the external accumulator and a brake cylinder; a pressure maintaining electromagnetic valve arranged at an overflow port of the proportional electromagnetic valve, the overflow port of the proportional electromagnetic valve is connected to the oil tank through the pressure maintaining electromagnetic valve; a brake cylinder sensor for collecting brake cylinder pressure output to the brake cylinder; a brake cylinder pressure switch electrically connected with the brake cylinder sensor; wherein, when the control system is in a relief working condition, the proportional electromagnetic valve is configured to be in a power-off state, and the pressure maintaining electromagnetic valve is configured to be in a power-on state; when the control system is switched from the relief working condition to an idle working condition or a braking working condition, the proportional electromagnetic valve is controlled to be switched to a power-on state, and after a preset time period, the pressure maintaining electromagnetic valve is switched to a power-off state.

2. The hydraulic brake cylinder pressure control system of claim 1, wherein, The control system is pre-configured with proportional electromagnetic valve fault conditions and / or pressure maintaining electromagnetic valve fault conditions, and if the proportional electromagnetic valve and / or the pressure maintaining electromagnetic valve meets the conditions, fault diagnosis is performed on the proportional electromagnetic valve and / or the pressure maintaining electromagnetic valve.

3. The hydraulic brake cylinder pressure control system of claim 2, wherein, The proportional electromagnetic valve fault condition is configured as: the pressure maintaining electromagnetic valve is in a power-off state, and the absolute value of the difference between the control target pressure value and the brake cylinder pressure is greater than a first fault threshold.

4. The hydraulic brake cylinder pressure control system of claim 2, wherein, The pressure maintaining electromagnetic valve fault condition is configured as: the pressure maintaining electromagnetic valve is in a power-on state, and after the preset time period, the absolute value of the difference between the pressure value of the accumulator and the brake cylinder pressure is greater than a second fault threshold.

5. The hydraulic brake cylinder pressure control system of claim 1, wherein, A current detection circuit is further arranged and electrically connected with the proportional electromagnetic valve, for acquiring current collection value of the proportional electromagnetic valve.

6. A hydraulic brake cylinder pressure control method for controlling the hydraulic brake cylinder pressure control system according to any one of claims 1 to 5, characterized by, The control system comprises: a pressure control step for judging whether the proportional electromagnetic valve is faulty and the control target pressure value is greater than the relief working condition control target value, if yes, configuring the pressure maintaining electromagnetic valve to be in a power-on state, the proportional electromagnetic valve to be in a power-off state, and setting the control target pressure value to 0, otherwise, performing pressure control according to the current working condition of the rail vehicle; a pressure control working condition judgment step for judging whether the current working condition is a traction working condition and the control target pressure value is greater than the relief working condition control target value, if yes, further judging whether the actual brake cylinder pressure is greater than a preset target value, otherwise, configuring the proportional electromagnetic valve to be in a power-on state, and configuring the control target pressure value to be a non-relief working condition control target value, and then performing idle working condition pressure control or braking working condition pressure control.

7. The hydraulic brake cylinder pressure control method of claim 6, wherein, The pressure control working condition judgment step further comprises: a relief working condition pressure control step for, if it is judged that the actual brake cylinder pressure is greater than the preset target value, configuring the pressure maintaining electromagnetic valve to be in a power-on state and the proportional electromagnetic valve to be in a power-off state after a delay relief response time, and configuring the control target pressure value to be 0; otherwise, configuring the pressure maintaining electromagnetic valve to remain in a power-off state, the proportional electromagnetic valve to remain in a power-on state, and configuring the control target pressure value to remain as the relief working condition control target value.

8. The hydraulic brake cylinder pressure control method of claim 6, wherein, The pressure control working condition judgment step further comprises: The idling condition pressure judgment step is executed if the current condition is an idling condition and the speed of the rail vehicle is greater than a preset speed threshold value, otherwise, an idling condition pressure control is performed. The idling condition pressure control step is executed if the pressure maintaining electromagnetic valve is in an energized state, otherwise, the proportional electromagnetic valve is configured to be in an energized state and the control target pressure value is configured to be an idling condition control target value.

9. The hydraulic brake cylinder pressure control method of claim 6, wherein, The pressure control condition judgment step further comprises: The braking condition pressure control step is executed if the current condition is a braking condition, and the pressure maintaining electromagnetic valve is in an energized state, otherwise, the proportional electromagnetic valve is configured to be in an energized state and the control target pressure value is configured to be a braking condition control target value.

10. The hydraulic brake cylinder pressure control method of claim 9, wherein, The fault redundancy control step is executed if the proportional electromagnetic valve is faulty, the pressure maintaining electromagnetic valve is not faulty, and the control target pressure value is greater than the mitigation condition control target value, otherwise, the pressure maintaining electromagnetic valve is configured to be in an energized state, the proportional electromagnetic valve is configured to be in a de-energized state, and the control target pressure value is configured to be 0. The fault redundancy control step is executed if the proportional electromagnetic valve is faulty, the pressure maintaining electromagnetic valve is not faulty, and the control target pressure value is greater than the mitigation condition control target value, otherwise, the pressure maintaining electromagnetic valve is configured to be in an energized state, the proportional electromagnetic valve is configured to be in a de-energized state, and the control target pressure value is configured to be 0.

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