Train emergency braking system and control method

Abstract

According to the train emergency braking system and the control method, after compressed air supplied to an air cylinder enters the emergency braking system through a UB air path connector, a pressure regulating valve is firstly arranged to depressurize UB compressed air, and the pressure of the UB compressed air is reduced to a proper pressure value P1; the decompressed compressed air is divided into two paths through a three-way connector, one path is sequentially provided with a high-speed inflation electromagnetic valve, a high-speed exhaust electromagnetic valve, a pressure sensor and a test connector, and the high-speed inflation electromagnetic valve and the high-speed exhaust electromagnetic valve are high-speed switch electromagnetic valves; and the other path is provided with another pressure reducing valve, so that the gas pressure of the pipeline is reduced to the minimum emergency braking guarantee pressure P2. The problem that in the prior art, the optimal emergency braking pressure cannot be obtained in real time according to the existing train operation environment and the existing train conditions is solved, the risks of wheel rubbing and insufficient braking force are reduced, and the technical problem that the braking distance exceeds the standard is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit braking, and particularly to an emergency braking system and control method for trains. Background Art

[0002] In the process of rail vehicle braking control, the braking system is a key system to ensure the safe operation of trains, and its main purpose is to realize the train speed regulation function and reliable braking to stop. In terms of composition, the braking system can be divided into three major parts: the driver command device, the command transmission device, and the braking execution device. When the braking system works, the driver command device issues a braking command, and after the braking command is transmitted, the braking execution device of each single vehicle applies braking force to realize train deceleration. In terms of the generation method of braking force, in the prior art, the commonly used methods are air friction braking and regenerative braking. Air friction braking uses an air brake cylinder to push the brake caliper to hold the wheel tightly and output braking force. Regenerative braking can convert the kinetic energy of the train into electrical energy by reversing the traction motor and feed it back to the power grid, which is a green and economical braking method.

[0003] From the perspective of in-service vehicle operation, the current control methods for emergency braking of high-speed multiple units are as follows: The emergency braking UB is pure air braking, and to ensure the reliable application of braking force, other various braking methods do not participate. The existing emergency braking air circuit schematic diagram is shown in Figure 1 、 Figure 2 ; the corresponding output emergency pressure curve diagram is shown in Figure 4 、 Figure 5 ; and the corresponding control flowcharts are shown in Figure 7 、 Figure 8 respectively.

[0004] During operation, the train may encounter the following extreme operating conditions: earthquakes, landslides, line interruptions, foreign objects invading the track, etc., which pose great hazards to the safe operation of the train. At this time, if the train has the function of adjustable emergency braking pressure and real-time optimization of emergency pressure according to the braking result, and makes the best use of the current wheel-rail adhesion coefficient, it can stop within a shorter braking distance and avoid wheel rubbing, thus staying away from risks and reducing losses; and when the train abnormally loses power, it can immediately apply the minimum guaranteed pressure of emergency braking to control the train to stop. Therefore, it is necessary to change the existing emergency braking system that can only output emergency pressure in a limited fixed pressure or stage linear pressure regulation method to meet the emergency braking function of "caused by non-vehicle reasons, requiring an ultra-short stopping distance and avoiding wheel rubbing". Summary of the Invention

[0005] In view of the current situation that the existing emergency braking system of rail transit vehicles cannot output the current optimal emergency braking pressure according to the train speed, vehicle weight, and actual wheel-rail adhesion coefficient during emergency braking, the present invention proposes a new design scheme for an emergency braking system that can collect wheel-rail information in real time to calculate the adhesion coefficient and accurately calculate and precisely output the emergency braking pressure in combination with the current vehicle speed and vehicle weight. This scheme can reduce the probability of train skidding during emergency braking and shorten the time required for the train to eliminate skidding, thereby avoiding wheel rubbing and achieving emergency braking with the shortest distance.

[0006] The object of the present invention is achieved through the following technical solutions.

[0007] In a train emergency braking system, after the compressed air from the supply air cylinder enters the emergency braking system through the UB air path interface, a pressure regulating valve is first set to reduce the pressure of the compressed air in the UB path to a suitable pressure value P1; then the decompressed compressed air is divided into two paths through a tee joint. One path is sequentially provided with a high-speed inflation solenoid valve, a high-speed exhaust solenoid valve, a pressure sensor, and a test joint, and both the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve are high-speed switch solenoid valves; the other path is provided with another pressure reducing valve to reduce the pipeline gas pressure to the minimum guaranteed pressure P2 for emergency braking.

[0008] A two-way valve is set to connect the two paths of compressed air to the input end of the two-way valve, and a side-exhaust emergency switch solenoid valve is provided at the output end of the two-way valve. When the side-exhaust emergency switch solenoid valve is energized, the compressed air at the rear end is exhausted. The compressed air after passing through the side-exhaust emergency switch solenoid valve enters the input port of the relay valve AC2 for flow amplification, and then enters the vehicle brake cylinder through the output port of the relay valve.

[0009] During train operation, both the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve are in a normally de-energized state, and the side-exhaust emergency switch solenoid valve is in a normally energized state; the air pressure at the rear end of the high-speed exhaust solenoid valve is the emergency braking pressure during normal emergency braking of the vehicle; when the emergency braking application command is valid, the side-exhaust emergency switch solenoid valve is in a de-energized state, and the emergency braking path is in an open state; the EBCU controls the emergency braking pressure by controlling the energization and de-energization of the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve, and adjusts the emergency braking output pressure through the actual pressure signal feedback of the pressure sensor.

[0010] When the high-speed inflation solenoid valve or the high-speed exhaust solenoid valve causes an air path break due to a jamming fault, the vehicle still outputs the minimum guaranteed pressure P2 for emergency braking to ensure the train stops; when the train emergency braking pressure is normally applied, the emergency braking pressure of each carriage of the train is steplessly adjusted between the two preset pressures P2 and P1.

[0011] A train emergency braking control method, the steps include: after the emergency braking pressure is output to the brake cylinder, the EBCU will continuously monitor the deviation between the actual output pressure of the train and the theory through the pressure sensor, wheel speed sensor, and vehicle speed sensor, judge whether there is skidding between the wheel and rail and the magnitude of the actual deceleration of the train, so as to improve the actual output pressure, skidding state and adjust the actual deceleration of the train by controlling the energization and de-energization of the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve, so that the train can avoid skidding and be more stable with the theoretical deceleration curve, and realize the closed-loop control of the entire train emergency braking system.

[0012] The EBCU continuously detects whether the emergency braking instruction is valid and whether each sensor fails. When a sensor failure is detected, the EBCU reports it to the train network control driver's cab and pops up a fault message on the screen; the EBCU calculates the current wheel-rail adhesion coefficient and the optimal emergency braking pressure through the data collected by each sensor; when the emergency braking instruction is detected to be valid, it controls the air circuit of the emergency braking system to conduct and output; at the same time, the EBCU monitors and feedbacks the vehicle emergency braking pressure, skidding state, and actual deceleration through each relevant sensor, and then adjusts and optimizes the emergency output pressure through the control actuator, so that the output of the entire system meets the control expectation.

[0013] While performing the emergency braking operation, the system autonomously learns and iteratively optimizes the adhesion and emergency braking force algorithms with the newly obtained empirical data.

[0014] Compared with the current emergency braking systems of Harmony and Fuxing high-speed trains, the advantages of the present invention are as follows: when the driver's manual operation causes the side exhaust emergency switch solenoid valve to lose power, the present invention can calculate the current adhesion coefficient of each vehicle more accurately, and the actuator also has the ability to immediately output a pressure close to the best emergency braking pressure into the brake cylinder, thereby reducing the probability of skidding and locking between the wheel and rail, shortening the anti-skid valve exhaust adjustment time, and obtaining the minimum emergency braking distance. When the train loses power completely due to an accident, the side exhaust emergency switch solenoid valve can still be opened to provide the minimum emergency braking guarantee pressure P2 for the vehicle.

[0015] In addition, the present invention can continuously optimize and iterate the algorithm according to the accumulated emergency braking data and anti-skid test data, so as to continuously improve the accuracy of emergency braking pressure calculation and output, making it more and more approaching the actual optimal emergency braking pressure. Since the data used for these iterations and optimizations directly come from individual trains, considering the performance and response speed differences of the components of each train, it is more targeted. Brief Description of the Drawings

[0016] Figure 1 It is the pneumatic circuit schematic diagram of the emergency braking system of the Harmony train;

[0017] Figure 2 It is the pneumatic circuit schematic diagram of the emergency braking system for Fuxing bullet trains;

[0018] Figure 3 It is the pneumatic circuit schematic diagram of the present invention;

[0019] Figure 4 It is the output pressure curve graph of the emergency braking system for Harmony bullet trains;

[0020] Figure 5 It is the output pressure curve graph of the emergency braking system for Fuxing bullet trains;

[0021] Figure 6 It is the output pressure calculation model graph of the present invention;

[0022] Figure 7 It is the control flow chart of the emergency braking system for Harmony bullet trains;

[0023] Figure 8 It is the control flow chart of the emergency braking system for Fuxing bullet trains;

[0024] Figure 9 It is the control flow chart of the present invention.

[0025] In the figure: 01. Side-discharge pressure reducing valve; 02. High-speed inflation solenoid valve; 03. High-speed exhaust solenoid valve, two-position three-way high-speed switch solenoid valve; 04. Test joint; 05. Pressure sensor; 06. Side-discharge pressure reducing valve; 07. Two-way valve; 08. EPLA electro-pneumatic conversion valve; 09. Side-discharge emergency switch solenoid valve; 10. Relay valve; 11. Emergency solenoid valve; 12. B11 emergency pressure regulating valve; 13. Empty and load adjustment valve; 14. Emergency switch solenoid valve.

[0026] Figure 1 , Figure 4 and Figure 7 are used to illustrate the output and control principles of an emergency braking system for Harmony bullet trains, as well as its final output results.

[0027] Figure 2 , Figure 5 and Figure 8 are used to illustrate the output and control principles of an emergency braking system for Fuxing bullet trains, as well as its final output results.

[0028] The output and control principles of the above two emergency braking systems for trains are only for reference, and are used to illustrate the pneumatic circuit principle design, control principle and output characteristics of typical emergency braking systems for existing high-speed trains. Specific embodiments

[0029] The present invention will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0030] After the compressed air in the supply air cylinder enters the emergency braking system through the UB air path interface, a pressure regulating valve is first set to reduce the pressure of the UB compressed air and lower its pressure to a suitable pressure value P1. Then, the decompressed compressed air is divided into two paths through a tee joint. One path is sequentially provided with a high-speed charging solenoid valve, a high-speed exhaust solenoid valve, a pressure sensor, and a test joint. The high-speed charging solenoid valve is a two-position two-way high-speed switch solenoid valve, and the high-speed exhaust solenoid valve is a two-position two-way high-speed switch solenoid valve. The other path is provided with another pressure reducing valve to reduce the pipeline gas pressure to the minimum guaranteed pressure P2 for emergency braking. Subsequently, a two-way valve is set to connect the above two paths of compressed air to the input end of the two-way valve. Next, a side-exhaust emergency switch solenoid valve is set at the output end of the two-way valve. When this solenoid valve is energized, it can discharge the compressed air at the rear end. The compressed air after passing through the side-exhaust emergency switch solenoid valve enters the input port of the relay valve AC2 for flow amplification, and then enters the vehicle brake cylinder through the output port of the relay valve.

[0031] During train operation, both the high-speed charging solenoid valve and the high-speed exhaust solenoid valve are in the normally de-energized state, and the side-exhaust emergency switch solenoid valve is in the normally energized state. The air pressure at the rear end of the high-speed exhaust solenoid valve is the emergency braking pressure during normal emergency braking of the vehicle. When the emergency braking application instruction is valid, the side-exhaust emergency switch solenoid valve is in the de-energized state, and the emergency braking path is in the open state; the EBCU controls the emergency braking pressure by controlling the energization and de-energization of the high-speed charging solenoid valve and the high-speed exhaust solenoid valve, and adjusts the emergency braking output pressure through the feedback of the actual pressure signal of the pressure sensor.

[0032] Since the emergency braking pressure is controlled by the vehicle EBCU, the emergency braking pressure of the new train emergency braking system is vehicle-controlled, thus ensuring that the emergency braking pressure of each car of the train can be applied and adjusted separately. When the high-speed charging solenoid valve or the high-speed exhaust solenoid valve is blocked and fails, resulting in an air path break, the vehicle can still output the minimum guaranteed pressure P2 for emergency braking to ensure the train stops. When the emergency braking pressure of the train is applied normally, the emergency braking pressure of each car of the train can be steplessly adjusted between the two preset pressures P2 and P1.

[0033] Secondly, the new train emergency braking system can immediately output a pressure close to the current actual optimal emergency braking pressure, thereby reducing the probability of skidding and locking between the wheel and rail, reducing wheel rubbing, and shortening the emergency braking distance.

[0034] Since the optimal braking pressure during emergency braking is a multi-variable function, which is not only related to the vehicle speed and weight, but also closely related to the adhesion coefficient between the wheel and rail at the moment of emergency braking. The new train emergency braking system fully considers this actual situation. In addition to installing speed and air spring pressure sensors on each vehicle of the train, temperature and humidity, rain and snow volume, icing and sand sensors are also set. Combining the information such as the gradient of each driving section and the wheel-rail material stored in the database, the optimal emergency braking pressure required for the current vehicle at the current moment is calculated through models and algorithms. The models and algorithms are established under the guidance of the adhesion theory by collecting a large amount of anti-skid test data of the current vehicle, and can better match the actual adhesion situation of the current vehicle.

[0035] For the design of the air circuit principle of the present invention, refer to Figure 3 , the compressed air in the supply air cylinder is divided into two air circuit branches before entering the brake control device. One of the branches is the service braking system branch. The compressed air outputs the service braking pre-control pressure AC1 after linear proportional pressure regulation by the EPLA electro-pneumatic conversion valve, and then enters the AC1 input port of the relay valve. The other branch is the emergency braking system branch. The compressed air first passes through the side-exhaust pressure reducing valve to reduce the pressure of the compressed air in the UB circuit to a suitable pressure value P1. Then, the decompressed compressed air is divided into two paths through a tee joint. One of the paths is sequentially provided with a high-speed inflation solenoid valve, a high-speed exhaust solenoid valve, a pressure sensor and a test joint. The two-position three-way high-speed switch solenoid valve can exhaust the air circuit at the rear when it is energized. The other path is provided with another side-exhaust pressure reducing valve to reduce the pipeline gas pressure to the minimum guaranteed pressure P2 for emergency braking. A two-way valve is provided at the rear ends of the above two branches to finally connect the compressed air of the above two branches to the two input ports of the two-way valve. Next, a side-exhaust emergency switch solenoid valve is provided at the output end of the two-way valve. The solenoid valve can exhaust the compressed air at the rear when it is energized. The compressed air after passing through the side-exhaust emergency switch solenoid valve enters the AC2 input port of the relay valve. The AC1 pressure and the AC2 pressure are compared and output in the relay valve. When outputting, the selected input pressure remains unchanged and the flow rate is amplified, so as to increase the output power of the fluid. Subsequently, the compressed air enters the vehicle brake pipeline through the output port of the relay valve, and enters the brake cylinder through the vehicle anti-skid valve to push the clamp to do work.

[0036] When the train is running, the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve are both in the normally de-energized state; the side-exhaust emergency switch solenoid valve is in the normally energized state and exhausts the compressed air at the rear when it is energized. The air pressure at the rear of the high-speed exhaust solenoid valve is the emergency braking pressure during normal emergency braking of the vehicle. When the emergency braking application instruction is valid, the side-exhaust emergency switch solenoid valve is de-energized, and the emergency braking system circuit is in the open state; the EBCU controls the emergency braking output pressure by controlling the energization and de-energization of the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve, and adjusts the deviation of the emergency braking output pressure value through the actual pressure signal feedback of the pressure sensor.

[0037] The vehicle EBCU controls the output of the emergency braking pressure by controlling the energization and de-energization of the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve. Therefore, the emergency braking pressure of the new train emergency braking system is vehicle-controlled, ensuring that the emergency braking pressure of each car of the train can be applied and adjusted individually. When the high-speed inflation solenoid valve or the high-speed exhaust solenoid valve causes an air circuit break due to a jamming fault, the vehicle can still output the minimum guaranteed emergency braking pressure P2 to ensure the train stops. When the emergency braking pressure of the train is applied normally, the emergency braking pressure of each car of the train can be steplessly adjusted between two preset pressure values, P2 and P1.

[0038] Figure 9 is the control flow chart of the new train emergency braking system, Figure 6 and is its emergency pressure calculation model.

[0039] Since the optimal braking pressure during emergency braking involves many environmental factors, it is not only related to the vehicle speed and weight, but also closely related to the adhesion coefficient between the wheel and the rail during emergency braking. To output the most reasonable current emergency braking force, the new train emergency braking system installs speed, each air spring pressure, temperature and humidity, rain and snow volume, icing and sand sensors on each car of the train. At the same time, the basic information related to adhesion and emergency braking force calculation, such as the gradient of each driving section and the wheel-rail material, is stored in the train on-board database, and the optimal emergency braking pressure required by the current vehicle at the current moment is calculated through a large-capacity data model and algorithm.

[0040] After the emergency braking pressure is output to the brake cylinder, the EBCU will continuously monitor the deviation between the actual output pressure and the theoretical pressure of the train through the pressure sensor, wheel speed sensor, and vehicle speed sensor, judge whether there is skidding between the wheel and the rail and the magnitude of the actual deceleration of the train, and thus improve the actual output pressure, skidding state and adjust the actual deceleration of the train by controlling the energization and de-energization of the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve, so that the actual deceleration of the train is more stable and consistent with the theoretical deceleration curve while avoiding skidding, realizing the closed-loop control of the entire emergency braking system of the train.

[0041] The control process of the new train emergency braking system is as follows: The EBCU monitors in real time whether the emergency braking command is valid and whether each sensor fails. When a sensor failure is detected, the EBCU reports it to the train network, and a pop-up message indicating the failure appears in the driver's cab. The EBCU calculates the current wheel-rail adhesion coefficient and the optimal emergency braking pressure based on the data collected by each sensor. When the emergency braking command is detected to be valid, it controls the air circuit of the emergency braking system to conduct and output. At the same time, the EBCU monitors and feeds back the vehicle emergency braking pressure, skidding state, and actual deceleration through each relevant sensor, and then adjusts and optimizes the emergency output pressure in real time through the control actuator to make the output of the entire system meet the control expectation. While performing the emergency braking operation, the system autonomously learns and iteratively optimizes the adhesion and emergency braking force algorithms with the newly obtained empirical data.

[0042] A train emergency braking system and control method of the present invention. Compared with the existing technology, in order to make the emergency braking pressure of the new emergency braking system steplessly adjustable, an air circuit branch is added to the air circuit of the original emergency braking system, a high-speed inflation solenoid valve, a high-speed exhaust solenoid valve, and a pressure sensor are set, and a two-way valve is added at the same time. The new scheme can calculate the current adhesion coefficient according to the information of the external temperature, humidity, rain and snow volume, dust volume, etc. collected in real time, combined with the wheel-rail material and line gradient in its own database, and finally calculate the optimal emergency braking output pressure in combination with the air spring pressure and train speed information collected. At the same time, the pressure reducing valve and two-way valve in the emergency braking system can still maintain the set minimum guaranteed emergency braking pressure in the case of the failure of the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve. The present invention solves the problem that the train emergency braking pressure in the existing technology cannot obtain the optimal emergency braking pressure in real time according to the in-service operation environment and the conditions of the vehicle itself, reduces the risk of wheel rubbing and insufficient braking force, and avoids the technical problem of exceeding the braking distance.

Claims

1. A train emergency braking system, characterized in that After the compressed air supplied to the air cylinder enters the emergency brake system through the UB air line interface, a pressure regulating valve is first set to reduce the pressure of the UB line compressed air and reduce its pressure to an appropriate pressure value P1; then the compressed air after the pressure reduction is divided into two paths through a three-way joint, one of which is provided with a high-speed inflation solenoid valve, a high-speed exhaust solenoid valve, a pressure sensor and a test joint in sequence, and both the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve are high-speed switching solenoid valves; another pressure reducing valve is set on the other path to reduce the pipeline gas pressure to the minimum guaranteed pressure P2 for emergency braking.

2. A train emergency braking system according to claim 1, characterized in that A two-way valve is set to connect two routes of compressed air to the input end of the two-way valve, and a solenoid valve with a side discharge emergency switch is set at the output end of the two-way valve. When the solenoid valve with a side discharge emergency switch is energized, the rear end compressed air is discharged, and the compressed air after passing through the solenoid valve with a side discharge emergency switch enters the input port of the relay valve AC2 for flow amplification, and then enters the vehicle brake cylinder through the output port of the relay valve.

3. A train emergency braking system according to claim 2, characterized in that When the train is running, the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve are both normally in a power-off state, and the solenoid valve with side discharge emergency switch is normally in a power-on state; the air pressure at the rear end of the high-speed exhaust solenoid valve is the emergency brake pressure during normal emergency braking of the vehicle; when the emergency brake application command is valid, the solenoid valve with side discharge emergency switch is in a power-off state, and the emergency brake passage is in an open state; the EBCU controls the emergency brake pressure by controlling the power on and off of the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve, and adjusts the emergency brake output pressure through the actual pressure signal feedback from the pressure sensor.

4. A train emergency braking system according to claim 3, characterized in that When the high-speed inflation solenoid valve or the high-speed exhaust solenoid valve is stuck and the air circuit is broken, the vehicle still outputs the minimum guaranteed emergency braking pressure P2 to ensure that the train stops; when the train emergency braking pressure is applied normally, the emergency braking pressure of each car of the train is steplessly adjusted between the two pre-set pressures of P2 and P1.

5. A train emergency braking control method, characterized in that the steps include: After the emergency brake pressure is output to the brake cylinder, the EBCU will monitor the deviation between the actual output pressure and the theoretical one through the pressure sensor, wheel speed sensor and vehicle speed sensor, determine whether there is slippage between the wheel and rail and the actual deceleration of the train, and thus improve the actual output pressure, slippage state and adjust the actual deceleration of the train by controlling the gain and loss of power of the high-speed inflation solenoid valve and the high-speed exhaust solenoid valve, so that the train can avoid slipping while being more stable with the theoretical deceleration curve, thereby realizing closed-loop control of the entire emergency braking system of the train.

6. A train emergency brake control method according to claim 5, characterized in that the steps include: The EBCU constantly checks whether the emergency braking command is valid and whether the sensors are faulty. When a sensor fault is detected, the EBCU reports it to the train network control and the driver's cab pops up a screen to report the fault; the EBCU calculates the current wheel-rail adhesion coefficient and the optimal emergency braking pressure through the data collected by each sensor; when it is detected that the emergency braking command is valid, the emergency braking system air circuit is controlled to conduct the output; at the same time, the EBCU monitors and feedbacks the vehicle's emergency braking pressure, gliding state, and actual deceleration through various relevant sensors, and then adjusts and optimizes the emergency output pressure through the control actuator to make the output of the entire system meet the control expectations.

7. A train emergency braking control method according to claim 6, characterized in that While performing emergency braking operations, the system uses newly acquired experience data to autonomously learn and iteratively optimize the adhesion and emergency braking force algorithms.

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