A city rail transit vehicle return rescue braking system

Abstract

The application discloses a kind of city area rail transit vehicle return rescue braking system, the application studies the matching characteristics of function and performance with locomotive air brake, and the interface relationship with train itself electrical system, can realize the synchronous braking and relief with locomotive, to guarantee the braking synchronism when return and rescue, reduce train longitudinal impulse;And specifically study the air path design, electrical design and brake command conversion function of a certain type of city area rail transit vehicle under the working condition of locomotive return and locomotive rescue, and propose the problems that need to be paid special attention in the design of return rescue function and train electrical interface matching, the application is integrated in brake control unit, without setting train pipe and automatic brake system throughout the whole train, reduce equipment procurement cost;Realize the target of improving product integration, improving brake sensitivity, reducing train longitudinal impulse, protecting bogie equipment and improving train braking effect, meet the operation requirements of city area train return and rescue.

Description

Technical Field

[0001] This invention relates to rail transit return and rescue technology, and in particular to a braking system for the return and rescue of urban rail transit vehicles. Background Technology

[0002] The return of urban rail transit vehicles refers to the transportation process from the manufacturing plant to the user's depot after the vehicles are manufactured.

[0003] Rescue of urban rail transit vehicles refers to the rescue operation performed by a locomotive when a vehicle malfunctions during operation after being delivered to the user's depot and is unable to operate independently.

[0004] The existing technology's repatriation and rescue braking scheme for urban vehicles is incompatible with the function and performance of the locomotive's air brake, and is also incompatible with the interface of the train's own electrical system. This prevents urban vehicles from achieving synchronous braking and release with the locomotive, and also fails to guarantee braking synchronization during repatriation and rescue, or reduce longitudinal impulses of the train. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a repatriation and rescue braking system for urban rail transit vehicles. When the repatriation and rescue function of urban rail transit vehicles is integrated into the braking control unit, there is no need to set up a train pipe and automatic braking system that runs through the entire train, thus reducing equipment procurement costs. It achieves the goals of improving product integration, improving braking sensitivity, reducing longitudinal impulse of trains, protecting bogie equipment, and improving the braking effect of trains, thus meeting the application requirements of urban rail transit vehicle repatriation and rescue.

[0006] The objective of this invention is achieved through the following technical solutions.

[0007] A repatriation and rescue braking system for urban rail transit vehicles includes an automatic braking function component. This component comprises a brake controller, an equalization EP control module, a relay valve, front and rear shut-off valves, a brake cylinder emergency bypass, a brake cylinder EP module, an air distribution valve, a switching valve, and a comparison valve. During normal braking, the equalization EP control module receives braking commands from the locomotive brake controller handle to control the equalization cylinder pressure, which is then controlled via the front and rear shut-off valves and the relay valve to control the train pipe pressure. During emergency braking, the train pipe pressure is directly released to the atmosphere via electric vent valve 1 / 2, the vehicle length valve, the emergency valve, and electric vent valve 2.

[0008] When the vehicles are transported back by rail, the pressure reduction of the locomotive train pipe is converted into the braking electrical command of the urban vehicles, while ensuring the total air and power supply of the urban vehicles.

[0009] During locomotive rescue, the air pressure reduction signal emitted by the train pipe when the locomotive brakes is directly converted into an electrical braking signal for the urban railcar through the brake control unit.

[0010] The freight locomotive has a train pressure of 500 kPa and the passenger car has a pressure of 600 kPa. The maximum service braking output is achieved when the pressure is reduced by 140 kPa and 170 kPa respectively.

[0011] When the locomotive is under normal braking, the EBCU calculates the target pressure for brake cylinder pre-control based on the collected train pipe pressure and rate of change, and generates the brake cylinder pre-control pressure through the electronic distribution valve. The BCU controls the switching valve to open the electronic distribution valve.

[0012] When the locomotive brakes in an emergency, the EBCU controls the emergency bypass of the brake cylinder to open, and outputs the greater pressure generated by the comparison valve and the actuation valve to the brake cylinder. The pressure generated by the actuation valve comes from the switching valve. During emergency braking, the switching valve opens the pressure generated by the air distribution valve.

[0013] In return mode, the return locomotive provides two pressurized air channels: the main air duct and the train pipe. The main air duct of the return locomotive is connected to the main air duct of the urban railcar. The train pipe of the return locomotive is connected to the train pipe of the urban railcar. The urban railcar has only a short section of train pipe at the head and tail cars, which is divided into three channels: one enters the return device, one enters the brake control unit, and one enters the main air duct through a one-way valve and a shut-off valve.

[0014] Under normal circumstances, the city rail vehicles are supplied with sufficient compressed air by the air compressor unit of the return car through the main air duct. If the air compressor unit of the return car fails to supply air normally due to a malfunction, air can also be supplied to the main air duct of the city rail vehicle through the pre-installed air pipeline under the city rail vehicle, via the locomotive train pipe through a one-way valve and a shut-off valve, to ensure the normal air supply for the brakes, air springs and parking brake.

[0015] In return mode, the return car provides DC110V power to the urban railcar, and the braking control system performs normal air braking control and anti-skid control.

[0016] The return-to-work device detects the pressure in the train pipe using a pressure sensor, converts the air pressure reduction signal emitted during locomotive braking into an electrical braking signal for the urban railcars, connects to the urban railcar braking command lines 1, 2, and 3, and transmits it to the braking control units of each car. The return-to-work device also supplies power to the emergency braking loop of the urban railcars.

[0017] The driver's cab of the city vehicle is equipped with a return mode switch to provide a return mode signal to the brake control unit of each vehicle. The brake control unit applies the corresponding brake according to the brake command 1, 2, 3.

[0018] In rescue mode, the rescue locomotive provides two lines of pressurized air: the main air duct and the train air duct. The main air duct of the rescue locomotive is connected to the main air duct of the municipal vehicles; the train air duct of the return locomotive is connected to the train air duct of the municipal vehicles. The municipal vehicles only have a short section of train air duct at the head and tail of the cars, which is divided into two lines: one line enters the brake control unit, and the other line enters the main air duct through a one-way valve and a shut-off valve.

[0019] In rescue mode, the rescue locomotive provides DC110V power to the urban railcar, and the braking control system performs normal air braking control and anti-skid control.

[0020] The brake control unit detects the pressure of the train pipe through a pressure sensor, converts the air pressure reduction signal of the train pipe issued when the locomotive brakes into a braking electrical signal for the urban railcar, connects it to the braking commands 1, 2, and 3 of the train through line, and transmits it to the brake control unit of each car.

[0021] The driver's cab of the city vehicle is equipped with a return mode switch to provide a return mode signal to the brake control unit of each vehicle, and at the same time to supply power to the braking command electrical signal output by the brake control unit;

[0022] When the return mode switch of the Tc car coupled to the locomotive is closed, the braking command electrical signal output by the braking control unit of the coupled Tc car is powered, and the train pipe air pressure reduction signal issued when the locomotive brakes is converted into a local car braking electrical signal and connected to the train through line braking commands 1, 2, and 3 for transmission to the braking control units of each car.

[0023] In the return mode, the brake control unit will also output control signals for brake commands 1, 2, and 3 based on the train pipe pressure, which conflict with the control signals output by the return device. Therefore, in the return and rescue modes, the brake commands 1, 2, and 3 output by the brake control unit need to be shielded in the following manner.

[0024] During the return process, it is necessary to confirm that the return mode switch at the non-coupled end is in an open state, and disconnect the connecting cable from the brake command 1, 2, 3 signals output by the brake control unit at the coupled end to the through line of the train brake command 1, 2, 3 via the vehicle terminal block jumper; after the return is completed, restore the return mode switch and restore the cable connection from the brake command 1, 2, 3 signals output by the brake control unit to the through line of the train brake command 1, 2, 3.

[0025] During locomotive rescue, the train pipe pressure identified by the brake control unit of the non-coupling end Tc car is 0. The output signals of brake command 1, 2, and 3 will continuously output the command codes corresponding to level 7, affecting the brake control during the rescue.

[0026] The return mode switch of the non-coupled Tc car needs to be in the open state to prevent the output signal of the non-coupled Tc car's brake control unit from interfering with the brake control.

[0027] That is, only when the return mode switch is closed will the brake command output signals 1, 2, and 3 of the brake control unit be powered by DC 110V. After the rescue is completed, restore the return mode switch on the main control vehicle.

[0028] Regardless of whether it is in return mode or rescue mode, urban trains must activate the return mode hard line signal via the return mode switch. After the return mode hard line signal is activated, the braking function remains disabled. Before activating return mode or rescue mode, effective technical measures must be taken to ensure that the train does not roll away.

[0029] Compared to existing technologies, the advantages of this invention are as follows: This invention studies the matching characteristics of the locomotive's air brake function and performance, as well as the interface relationship with the train's own electrical system, enabling urban rail transit vehicles to achieve synchronous braking and release with the locomotive, ensuring braking synchronization during repatriation and rescue operations and reducing longitudinal impulses. It also specifically studies the air circuit design, electrical design, and braking command conversion function of urban rail transit vehicles under locomotive repatriation and rescue conditions, and proposes issues requiring special attention in the design, such as the matching of the repatriation and rescue function with the train's electrical interface. When the urban rail transit vehicle's rescue and repatriation function is integrated into the brake control unit, there is no need to set up a train pipe and automatic braking system running through the entire train, reducing equipment procurement costs. It achieves the goals of improving product integration, increasing braking sensitivity, reducing longitudinal impulses, protecting bogie equipment, and improving train braking effect, meeting the operational requirements of urban rail transit vehicle repatriation and rescue. Attached Figure Description

[0030] Figure 1 A certain type of urban rail transit vehicle.

[0031] Figure 2 Locomotive braking function block diagram.

[0032] Figure 3 Diagram showing the connection between the return vehicle and the ventilation duct of the city workshop.

[0033] Figure 4 Electrical connection diagram for feedback mode.

[0034] Figure 5 Diagram showing the connection between the rescue vehicle and the ventilation duct of the municipal workshop.

[0035] Figure 6 Electrical connection diagram for rescue mode.

[0036] Figure 7 Feedback mode, processing diagram of braking command 1, 2, 3 output signals.

[0037] Figure 8 Diagram of electrical signal processing at the non-connected end during the rescue operation. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0039] Taking a certain type of urban rail transit vehicle as an example, this paper analyzes and studies the locomotive return and locomotive rescue schemes.

[0040] 1. Overview of a certain type of urban vehicle

[0041] 1.1 Vehicle Formation

[0042] The train consists of 6 cars, such as Figure 1 As shown. Grouping format: =Tc-M-M-M-M-Tc=

[0043] Tc vehicle: a trailer with a driver's cab.

[0044] M-car: Driverless high-speed train

[0045] "-": Semi-permanent traction bar

[0046] "=": Fully automatic coupler

[0047] 2.2 Performance Parameters

[0048] Table 1. Braking-related performance parameters of vehicles in urban areas

[0049]

[0050] 2.3 Air supply and braking system

[0051] Each train is equipped with two AC-driven air compressors, and each car is equipped with a microcomputer-controlled direct-flow air braking system.

[0052] The microcomputer-controlled direct-flow air braking system controls the air path from the main air duct to the basic braking device according to the vehicle's electrical braking commands, applying air to apply braking and releasing air to relieve braking.

[0053] 2. Overview of locomotive braking function

[0054] Taking a locomotive equipped with the DK-2 type automatic air brake as an example, the automatic braking function mainly consists of a brake controller (automatic brake handle), an equalization EP control module, a relay valve, front and rear shut-off valves, a brake cylinder emergency bypass, a brake cylinder EP module, an air distribution valve, a switching valve, a comparison valve, etc. Figure 2 .

[0055] During normal braking, the equalization EP control module receives braking commands from the locomotive brake controller handle to control the equalization cylinder pressure, which is then controlled via the front and rear shut-off valves and relay valves to control the train pipe pressure. During emergency braking, the train pipe pressure can be directly released to the atmosphere via the electric vent valve 1 / 2, the car length valve, the emergency valve, and the electric vent valve 2.

[0056] The freight locomotive has a train pressure of 500 kPa and the passenger car has a pressure of 600 kPa. The maximum service braking output is achieved when the pressure is reduced by 140 kPa and 170 kPa respectively.

[0057] When the locomotive is under normal braking, the EBCU calculates the target pressure for brake cylinder pre-control based on the collected train pipe pressure and rate of change, and generates the brake cylinder pre-control pressure through the electronic distribution valve. The BCU controls the switching valve to open the electronic distribution valve.

[0058] When the locomotive brakes in an emergency, the EBCU controls the emergency bypass of the brake cylinder to open, and outputs the greater pressure generated by the comparison valve and the actuation valve to the brake cylinder. The pressure generated by the actuation valve comes from the switching valve. During emergency braking, the switching valve opens the pressure generated by the air distribution valve.

[0059] 3. Locomotive return function design scheme

[0060] When vehicles are transported back by rail, they are not powered on their own and require a locomotive to be coupled with other vehicles for operation; this is usually called a "no-powered return trip." Locomotives are typically grouped as follows: traction locomotive + return car + urban railcar + return car.

[0061] The key to locomotive return is to convert the locomotive train pipe pressure reduction into braking electrical commands for urban vehicles, while ensuring the total air and power supply for urban vehicles.

[0062] To adapt to different locomotives and match the braking rates of locomotives and urban vehicles, a portable feedback device with air-to-electric conversion function is set up. It consists of an electronic controller and a pressure sensor, which converts the air decompression signal emitted by the train pipe when the locomotive brakes into the braking electrical signal of the urban vehicle.

[0063] The return system can accommodate freight locomotives and rolling stock with a constant pressure of 500 kPa or passenger locomotives and rolling stock with a constant pressure of 600 kPa, employing a staged braking and single-release mode. Because urban rail vehicles have a higher maximum braking rate, the return system needs to limit the maximum braking rate, which can be set to level 4, 5, or 6 braking levels (the specific level depends on the return locomotive), so that urban rail vehicles and railway locomotives and rolling stock have essentially the same braking rate, ensuring safe return.

[0064] The return device is equipped with a return mode selection switch and a gear switch. When the return mode is selected as "freight car mode", the minimum pressure reduction is 40 kPa, and the train pipe pressure is identified according to the 500 kPa pressure system; when the return mode is selected as "passenger car mode", the minimum pressure reduction is 40 kPa, and the train pipe pressure is identified according to the 600 kPa pressure system.

[0065] 3.1 Gas Path Design

[0066] like Figure 3As shown, the return locomotive provides two lines of pressurized air: the main air duct and the train air duct. The return locomotive's main air duct is connected to the municipal vehicle's main air duct; the return locomotive's train air duct is connected to the municipal vehicle's train air duct. The municipal vehicle only has a short section of train air duct at the head and tail cars, which is divided into three lines: one line enters the return device, one line enters the brake control unit (this line is set up as an air connection during locomotive rescue), and one line enters the main air duct through a one-way valve and a shut-off valve.

[0067] Under normal circumstances, the city rail vehicles receive sufficient compressed air from the air compressor unit of the return vehicle through the main air duct. If the air compressor unit of the return vehicle fails to supply air normally due to a malfunction, air can also be supplied to the main air duct of the city rail vehicle through the pre-installed air pipeline under the city rail vehicle, via the locomotive train pipe through a one-way valve and a shut-off valve, to ensure the normal air supply for the brakes, air springs and parking brake.

[0068] 3.2 Electrical Function Design

[0069] like Figure 3 As shown, the return car provides DC110V power to the urban railcar so that the braking control system can perform normal air braking control and anti-skid control.

[0070] The return-to-work device detects the pressure in the train pipes using pressure sensors, converts the air pressure reduction signal emitted during locomotive braking into an electrical braking signal for the municipal vehicles, connects to the municipal vehicle braking command lines 1, 2, and 3, and transmits it to the braking control units of each vehicle. The return-to-work device also supplies power to the emergency braking loop of the municipal vehicles.

[0071] The driver's cab of the city-area vehicles is equipped with a return mode switch to provide a return mode signal to the brake control unit of each vehicle, so that the brake control unit can apply corresponding braking according to braking commands 1, 2, and 3. Figure 4 .

[0072] 3.3 Pressure-Level Signal Conversion

[0073] 3.3.1 Truck Mode

[0074] In freight car mode, the train pipe pressure is 500 kPa. Assuming the limiting level is N and the intermediate level is X, the conversion relationship between train pipe pressure, pressure reduction and level is shown in Table 2 for freight car mode.

[0075] Note: The braking level will only be changed to the current level when the pressure drops to the corresponding value; otherwise, it will remain at the previous braking level. For example, if the pressure is 370 kPa, the braking level will remain at N-1 until it drops to 360 kPa, at which point it will be changed to N.

[0076] For example, when the limit level is 6, the relationship between train pipe pressure, pressure reduction, and level conversion is shown in Table 3 for freight car mode.

[0077] 3.3.2 Bus Mode

[0078] In passenger car mode, the train pipe pressure is 600 kPa. Assuming the limiting level is N and the intermediate level is X, the conversion relationship between train pipe pressure, pressure reduction and level is shown in Table 2 for passenger car mode.

[0079] For example, when the limit level is 6, the conversion relationship between train pipe pressure, pressure reduction, and level is shown in Table 3 for passenger car mode.

[0080] Table 2 Pressure-Level Conversion Relationship

[0081]

[0082] Table 3 Pressure-Level Conversion Relationship at Limitation Level 6

[0083]

[0084] 3.3.3 Level Bit-Instruction Signal Conversion

[0085] The return device converts the train pipe pressure into the corresponding braking level according to the conversion relationship, and then outputs braking command 1, 2, 3 electrical control signals. The braking control unit controls the corresponding braking deceleration according to the electrical braking command, as shown in Table 4.

[0086] Table 4 Locomotive Return Braking Electrical Command Conversion

[0087]

[0088]

[0089] Note: β corresponds to the deceleration at maximum service braking.

[0090] To match the locomotive's braking characteristics, the return device switches between commands according to the phased braking and single-release modes.

[0091] Phased braking: Starting from the relief state (ON) and continuing to the limit state, the change in each braking level is phased braking.

[0092] First-stage relief: Starting from the pressure value corresponding to the rise from the lower braking level to the current braking level, relief is implemented when the increase in train pipe pressure exceeds Δh (the minimum pressure increase required for first-stage relief). For example, in passenger car mode, the maximum braking level is 6, Δh is 30 kPa, and the train pipe pressure is 440 kPa. Relief is implemented when the pressure rises to 486 kPa.

[0093] 4. Rescue Function Design Scheme

[0094] Unlike locomotive return, locomotive rescue requires convenient and quick operation. Therefore, the return device is no longer used, reducing the operation time for setting up and connecting the return device. The train pipe air decompression signal emitted when the locomotive brakes is directly converted into the urban vehicle braking electrical signal through the brake control unit.

[0095] Rescue vehicles typically operate at a constant pressure of 600 kPa, enabling them to provide total ventilation and power to vehicles within the city.

[0096] 4.1 Gas Path Design

[0097] like Figure 5 As shown, the rescue locomotive provides two lines of pressurized air: the main air duct and the train air duct. The main air duct of the rescue locomotive is connected to the main air duct of the municipal vehicles; the train air duct of the return locomotive is connected to the train air duct of the municipal vehicles. The municipal vehicles only have a short section of train air duct at the head and tail of the cars, which is divided into two lines: one line enters the brake control unit, and the other line enters the main air duct through a one-way valve and a shut-off valve.

[0098] 4.2 Electrical Function Design

[0099] like Figure 6 As shown, the rescue locomotive provides DC 110V power to the urban railcar so that the braking control system can perform normal air braking control and anti-skid control.

[0100] The brake control unit detects the pressure in the train pipe using a pressure sensor. It converts the air pressure reduction signal from the train pipe, emitted when the locomotive brakes, into a braking electrical signal for the city trains. This signal is then connected to the train's through-track braking commands 1, 2, and 3, and transmitted to the brake control units of each car. Figure 5 .

[0101] The driver's cab of the city vehicle is equipped with a return mode switch to provide a return mode signal to the brake control unit of each vehicle, and at the same time to supply power to the braking command electrical signal output by the brake control unit.

[0102] When the return mode switch of the Tc car coupled to the locomotive is closed, the braking command electrical signal output by the braking control unit of the coupled Tc car is powered, and the train pipe air pressure reduction signal issued when the locomotive brakes is converted into a local car braking electrical signal and connected to the train through line braking commands 1, 2, and 3 for transmission to the braking control units of each car.

[0103] 4.3 Pressure-Level Signal Conversion

[0104] After receiving the feedback mode signal, the brake control unit interprets the train pipe pressure reduction amount according to the 600kPa pressure and 7-level system, and converts it into brake command 1, 2, 3 electrical command signal output. The conversion relationship between train pipe pressure, pressure reduction amount and level is shown in Table 5.

[0105] Table 5 Relationship between locomotive rescue pressure conversion

[0106]

[0107] 4.4 Level Bit-Instruction Signal Conversion

[0108] According to the above conversion relationship, the braking control unit of the coupled end Tc car converts the train pipe pressure into the corresponding braking level according to the stage braking and one-time release method, and outputs braking command 1, 2, 3 electrical control signals. The braking control unit of each car controls the corresponding braking deceleration according to the electrical braking command, as shown in Table 6.

[0109] Table 6. Locomotive Rescue Braking Electrical Command Conversion

[0110]

[0111]

[0112] When the feedback mode signal is detected to be 0, the default output braking commands 1 / 2 / 3 are all 0.

[0113] 5. Key Design Considerations for Return and Rescue

[0114] (1) According to Figure 5 The electrical connections shown for locomotive rescue operations indicate that, in the return mode, the brake control unit will also output brake command signals 1, 2, and 3 based on the train pipe pressure, which conflict with the control signals output by the return device. Therefore, in return and rescue modes, the brake command signals 1, 2, and 3 output by the brake control unit need to be shielded as follows.

[0115] During the return process, it is necessary to confirm that the return mode switch at the non-coupled end is in the open state, and to disconnect the connecting cable from the brake command 1, 2, 3 signals output by the coupled end brake control unit to the train brake command 1, 2, 3 through line via the vehicle terminal block jumper. Figure 7 .

[0116] After the return is completed, restore the return mode switch and restore the brake command 1, 2, 3 signals output by the brake control unit to the train brake command 1, 2, 3 through-line cable connection.

[0117] (2) During locomotive rescue, the train pipe pressure identified by the non-coupling end Tc car brake control unit is 0. The brake command 1, 2, 3 output signals will continuously output the command code corresponding to level 7, affecting the brake control during rescue.

[0118] Therefore, the return mode switch of the non-coupled Tc car needs to be in the open state to prevent the output signal of the non-coupled Tc car's brake control unit from interfering with the brake control. Figure 8 As shown.

[0119] That is, only when the return mode switch is closed will the brake command output signals 1, 2, and 3 of the brake control unit be powered by DC 110V. After the rescue is completed, the return mode switch on the main control vehicle is restored.

[0120] (3) Regardless of whether it is return mode or rescue mode, the urban train must activate the return mode hard line signal through the return mode switch; after the return mode hard line signal is activated, the braking function is disabled. Therefore, before activating the return mode or rescue mode, effective technical measures must be taken to ensure that the vehicle does not roll away.

[0121] The return and rescue braking scheme of this type of urban rail transit vehicle focuses on the matching characteristics of the locomotive's air brake function and performance, as well as the interface relationship with the train's own electrical system, so that the urban rail vehicle can achieve synchronous braking and release with the locomotive.

[0122] The urban rail vehicles using this solution do not require a train pipe running through the entire train or an automatic braking system. The rescue and return function is integrated into the brake control unit, reducing equipment procurement costs. This achieves the goals of improving product integration, increasing braking sensitivity, reducing longitudinal impulses of the train, protecting bogie equipment, and improving the braking effect of the train, thus meeting the operational requirements of urban rail trains for return and rescue.

Claims

1. A repatriation and rescue braking system for urban rail transit vehicles, characterized in that... The system includes an automatic braking function component, which comprises a brake controller, an equalization EP control module, a relay valve, front and rear shut-off valves, a brake cylinder emergency bypass, a brake cylinder EP module, an air distribution valve, a switching valve, and a comparison valve. During normal braking, the equalization EP control module receives braking commands from the locomotive brake controller handle to control the equalization air cylinder pressure, which is then controlled via the front and rear shut-off valves and the relay valve. During emergency braking, the train pipe pressure is directly released to the atmosphere via electric vent valve 1, electric vent valve 2, the car length valve, and the emergency valve. When the vehicles are transported back by rail, the pressure reduction of the locomotive train pipe is converted into the braking electrical command of the urban vehicles, while ensuring the total air and power supply of the urban vehicles. During locomotive rescue, the train pipe air pressure reduction signal emitted when the locomotive brakes is directly converted into a local vehicle braking electrical signal through the brake control unit; In the return mode, the brake control unit also outputs control signals for brake commands 1, 2, and 3 based on the train pipe pressure, which conflict with the control signals output by the return device. Therefore, the vehicle shields the brake command signals 1, 2, and 3 output by the brake control unit in return and rescue modes as follows: During the return process, confirm that the return mode switch at the non-coupled end is not closed, and disconnect the connecting cable from the brake command signals 1, 2, and 3 output by the coupled end brake control unit to the through line of brake command signals 1, 2, and 3 on the train via the vehicle terminal block jumper. After the return is completed, restore the return mode switch and restore the cable connection from the brake control unit outputting brake command signals 1, 2, and 3 to the through line of brake command signals 1, 2, and 3 on the train. During locomotive rescue, the non-coupled end Tc car... The brake control unit identifies the train pipe pressure as 0, and the output signals of brake commands 1, 2, and 3 will continuously output command codes corresponding to level 7, affecting brake control during rescue. The return mode switch of the non-coupled Tc car is in an open state to prevent the output signals of the brake control unit of the non-coupled Tc car from interfering with the brake control. That is, when the return mode switch is closed, the output signals of brake commands 1, 2, and 3 of the brake control unit are powered by DC110V. After the rescue is completed, the return mode switch of the main control car is restored. Regardless of the return mode or the rescue mode, the urban train activates the return mode hard-line signal through the return mode switch. After the return mode hard-line signal is activated, the braking function remains disabled. Before activating the return mode or the rescue mode, technical measures are taken to ensure that the vehicle does not roll away.

2. The urban rail transit vehicle return and rescue braking system according to claim 1, characterized in that... The freight locomotive has a train pressure of 500 kPa and the passenger car has a pressure of 600 kPa. The maximum service braking output is achieved when the pressure is reduced by 140 kPa and 170 kPa respectively.

3. The urban rail transit vehicle return and rescue braking system according to claim 1, characterized in that... During service braking, the EBCU calculates the target pressure for brake cylinder pre-control based on the collected train pipe pressure and rate of change, and generates the brake cylinder pre-control pressure through the electronic distribution valve. The BCU controls the switching valve to open the electronic distribution valve and activate the actuating valve. During emergency braking, the EBCU controls the brake cylinder emergency bypass to open, and outputs the larger pressure generated by the comparison valve and the actuating valve to the brake cylinder. The pressure generated by the actuating valve comes from the switching valve. During emergency braking, the switching valve activates the pressure generated by the air distribution valve.

4. A repatriation and rescue braking system for urban rail transit vehicles according to any one of claims 1-3, characterized in that... In return mode, the return locomotive provides two lines of compressed air: the main air duct and the train air duct. The main air duct of the return locomotive is connected to the main air duct of the urban railcar. The train air duct of the return locomotive is connected to the train air duct of the urban railcar. The urban railcar only has a short section of train air duct at the head and tail of the car, which is divided into three lines: one line enters the return device, one line enters the brake control unit, and one line enters the main air duct through a one-way valve and a shut-off valve. Under normal circumstances, the urban railcar receives sufficient compressed air from the air compressor unit of the return car through the main air duct. If the air compressor unit of the return car fails to supply air normally due to a malfunction, air can also be supplied to the main air duct of the urban railcar through the pre-set air pipeline under the urban railcar, via the locomotive train air duct, a one-way valve, and a shut-off valve, to ensure normal air supply for the brakes, air springs, and parking brake.

5. A repatriation and rescue braking system for urban rail transit vehicles according to any one of claims 1-3, characterized in that... In return mode, the return car provides DC110V power to the urban railcar, and the braking control system performs normal air braking control and anti-skid control. The return device detects the pressure of the train pipe through a pressure sensor, converts the air pressure reduction signal of the train pipe emitted when the locomotive brakes into an electrical braking signal for the urban railcar, connects to the urban railcar braking command 1, 2, 3 through line, and transmits it to the braking control unit of each car. The return device also supplies power to the emergency braking loop of the urban railcar. The driver's cab of the urban railcar is equipped with a return mode switch to provide return mode signals to the braking control unit of each car. The braking control unit applies corresponding braking according to braking command 1, 2, 3.

6. A repatriation and rescue braking system for urban rail transit vehicles according to any one of claims 1-3, characterized in that... In rescue mode, the rescue locomotive provides two lines of pressurized air: the main air duct and the train air duct. The main air duct of the rescue locomotive is connected to the main air duct of the urban railcars. The train air duct of the return locomotive is connected to the train air duct of the urban railcars. The urban railcars only have a short section of train air duct at the head and tail of the cars, which is divided into two lines. One line enters the brake control unit, and the other line enters the main air duct through a one-way valve and a shut-off valve.

7. A repatriation and rescue braking system for urban rail transit vehicles according to any one of claims 1-3, characterized in that... In rescue mode, the rescue locomotive provides DC 110V power to the urban railcar, and the braking control system performs normal air braking control and anti-skid control. The braking control unit detects the pressure of the train pipe through a pressure sensor, converts the air decompression signal of the train pipe emitted when the locomotive brakes into an urban railcar braking electrical signal, and connects it to the braking commands 1, 2, and 3 of the train through line, transmitting them to the braking control units of each car. The urban railcar driver's cab is equipped with a return mode switch, which provides a return mode signal to the braking control units of each car, and simultaneously supplies power to the braking command electrical signals output by the braking control units. When the return mode switch of the Tc car coupled to the locomotive is closed, the braking command electrical signals output by the braking control units of the coupled Tc car are powered, enabling the conversion of the air decompression signal of the train pipe emitted when the locomotive brakes into an urban railcar braking electrical signal, which is then connected to the braking commands 1, 2, and 3 of the train through line and transmitted to the braking control units of each car.

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