Method for determining an optimal or maximum permissible speed of a rail vehicle

Abstract

The invention relates to a method for determining an optimal or maximum permissible speed of a rail vehicle depending on a thermal state of a friction element of a friction brake of the rail vehicle, comprising the steps of a) detecting parameters characterizing a current driving situation of the rail vehicle, b) determining or estimating a first influence on the thermal state of the friction element based on the current driving situation of the rail vehicle, the method comprising at least the further steps of c) determining or estimating a second influence on the thermal state of the friction element, which, in addition to the first influence, affects the thermal state of the friction element when a defined type of braking is virtually or theoretically performed in the current driving situation of the rail vehicle, d) determining the optimal or maximum permissible speed of the rail vehicle such that, under the first influence and under the second influence on the friction element, d1) an allowed maximum element temperature of the friction element is not exceeded or d2) an allowed maximum element temperature of the friction element occurs on the friction element.

Description

Technical Field

[0001] The present invention relates to a method for determining the optimal or maximum permissible speed of a rail vehicle based on the thermal state of at least one friction element of at least one friction brake of the rail vehicle. Background Technology

[0002] Rail vehicles typically have electric brakes and additionally a friction braking system (hybrid), in which the electric brakes are preferred to reduce wear on the friction braking system. Some rail vehicles have a friction braking system but not an electric brake.

[0003] Therefore, in the event of complete or partial failure of the electric brakes, braking, especially service braking, must be performed primarily or solely using the friction braking system. The higher the weight of the vehicle being braked by the friction braking system, and the higher the braking entry speed of the rail vehicle—that is, the higher the speed—the greater the energy input required to initiate friction braking, and consequently, the higher the temperature rise of the brake discs and brake pads. As a result, the fluctuation of the friction coefficient μ of the brake disc-brake pad pair increases, and therefore the probability of a decrease in the friction coefficient μ increases. Therefore, at high braking entry speeds, there is a risk of prolonged braking path due to brake weakening.

[0004] Here, brake attenuation (brake fade) is understood as the reduction in braking effect of a friction braking system due to factors such as heat or moisture. To avoid brake attenuation caused by heating, the maximum speed of a rail vehicle is limited by a maximum permissible speed, depending on the circumstances.

[0005] To this end, WO2018 / 054736A1 of the aforementioned type proposes a method and apparatus for influencing the kinematic behavior of a vehicle having at least one friction braking system, wherein braking action is generated by the relative compression of at least one first friction element and a second friction element, wherein the temperature of at least the first friction element is calculated from information about the vehicle's speed, braking pressure, external temperature, and absolute time, and the calculation takes into account heat conduction through the at least first friction element and speed-related cooling of the at least first friction element, and the influence on the vehicle's kinematic behavior is based on the calculation. Summary of the Invention

[0006] In contrast, the objective of this invention is to provide a method that, on the one hand, provides greater safety in preventing overheating of the friction braking system, but on the other hand, enables the rail vehicle to achieve the highest possible speed, i.e., to travel "at the limit" at the optimal speed.

[0007] The background of this invention is that the maximum permissible speed in terms of the thermal state or thermal load capacity of at least one friction element is also the optimal speed, because the "thermal reserve" of said at least one friction element is maximized without damage due to overheating. The rail vehicle is capable of operating at the maximum speed that is just permissible in terms of the thermal load capacity of said at least one friction element. It is clear here that the rail vehicle has multiple friction brakes, for example, in the form of disc brakes and / or block brakes, so that, for example, the friction brake with the highest thermal load, as the weakest (thermally) weakest link, can form a metric for determining the optimal or maximum permissible speed of the rail vehicle. The maximum permissible speed or optimal speed of the rail vehicle is simplified below by v. opt express.

[0008] Another consideration of this invention is that, at all times during the operation or travel of a rail vehicle, it should be ensured that a defined type of braking can be performed with a defined braking action, such as emergency braking, forced braking, or rapid braking, without causing the temperature of the friction elements (e.g., the brake disc temperature) to reach a critical range due to the resulting temperature variable ΔT.

[0009] Rail vehicles here should be understood as any type of rail-bound vehicle with a drive mechanism, especially a traction vehicle, or without a drive mechanism, such as a car in a rail vehicle assembly, as well as rail vehicle assemblies consisting of multiple rail vehicles.

[0010] This invention is based on a method for determining the optimal or maximum permissible speed v of a rail vehicle according to the thermal state of at least one friction element of at least one friction brake. opt The method, the method comprising at least the following steps:

[0011] a) Detect at least one parameter characterizing the current operating status of the rail vehicle.

[0012] b) Determine or estimate a first impact on the thermal state of the at least one friction element based on the current operating conditions of the rail vehicle.

[0013] According to the present invention, the method is characterized by the following additional steps:

[0014] c) Determine or estimate a second (especially speed-related) effect on the thermal state of the at least one friction element, which, when braking is virtually or theoretically performed with a defined braking type during the current operating conditions of the rail vehicle, would affect the thermal state of the at least one friction element.

[0015] d) This determines the optimal or maximum permissible speed v of the rail vehicle. optSuch that on the at least one friction element, under the first influence and under the second influence

[0016] d1) The maximum permissible temperature T of the friction element does not exceed that of the at least one friction element. max ,or

[0017] d2) The maximum permissible friction element temperature T of at least one of the friction elements essentially occurs. max .

[0018] This method ensures that the defined braking type, such as emergency braking, can be performed at every point in time during the operation of the rail vehicle without causing the temperature of at least one friction element to exceed the permissible maximum friction element temperature T. max Therefore, the additional temperature variable ΔT generated by the defined braking type is considered as a factor in determining the optimal speed v. opt The second impact of time.

[0019] Here, it is preferable to perform the estimation or calculation of the temperature variable ΔT continuously at each time point and / or during driving before actually implementing the defined braking type, even though the defined braking type is not actually implemented. Therefore, it is not mandatory to actually implement the defined braking type in parallel with the current driving conditions. The estimation or calculation of the temperature variable ΔT based on virtual braking is performed for safety reasons to avoid temperature overload of at least one friction element of the friction braking system at each time point of driving, but the actual implementation of the defined braking type is not mandatory here.

[0020] Therefore, the initial conditions form the current operating condition, in which the rail vehicle travels at a determined speed and load, and under determined environmental and path conditions, along a path that is, for example, flat or with a determined downhill or uphill gradient. For example, speed, load, downhill gradient, or uphill gradient is then detected as parameters. The current operating condition may also include the activation of, for example, service braking of a different type than the defined braking type, wherein, for example, the current braking pressure and / or the current braking force and / or the current braking torque are then detected as parameters. Alternatively, braking may not be performed in the current operating condition, in which case the parameters relating to the current braking pressure and / or the current braking force and / or the current braking torque are equal to zero. Furthermore, alternatively, braking with the defined braking type may also be possible in the current operating condition.

[0021] Based on the current operating conditions, the temperature T of the friction elements, for example, can be calculated or estimated using a model, based on the current operating conditions of the rail vehicle. pred The first temperature component Tcurrent The first temperature component T current Then, corresponding to the temperature actually set on at least one friction element due to the current driving conditions, the first temperature component T... current For example, it is continuously calculated, even if a specific braking type is currently being executed.

[0022] The model should be understood as any physical mathematical model that can be implemented by a storable program in a computing unit and by means of the model that the parameters can be calculated based on the parameters.

[0023] The parameters and / or characteristic parameters used to characterize the current driving conditions are not, in particular, temperature parameters. The predictive friction element temperature T can then be estimated or calculated from at least one parameter using a model. pred The first temperature component T current However, for example, the first temperature component T current It is not measured by a temperature sensor. However, alternatively or additionally, at least one temperature sensor may be used to directly or indirectly detect the first temperature component T. current .

[0024] Furthermore, for example, the temperature variable ΔT representing the second influence is considered as the predictive friction element temperature T. pred The second temperature component ΔT can be considered as a second influence. This is used to predict the temperature T of the friction element. pred The temperature variable ΔT of the second temperature component is particularly related to speed. If, under the current operating conditions of the rail vehicle, braking is virtually performed with a defined braking type that is not or has not yet been required under the current operating conditions but could be required under the current operating conditions, then the second temperature component ΔT is added to the first temperature component T. current It appears on at least one friction element of a friction braking system.

[0025] For example, the predictive friction element temperature T of at least one friction element in a friction braking system. pred It can be determined as the first temperature component T current The sum of the second temperature component ΔT. Therefore, when the defined braking type is applied under the current driving conditions, the predictive friction element temperature T... pred It is theoretically or virtually set on or in at least one friction element, estimated or calculated.

[0026] Therefore, the present invention is particularly based on the consideration that a second temperature component or temperature variable ΔT is provided as a "temperature reserve" (the second temperature component or temperature variable is also provided, for example, for increasing the current speed of the rail vehicle to the optimal speed v). opt(corresponding to the highest permissible friction element temperature T at at least one friction element) max and the first temperature component T current The difference between them:

[0027] ΔT=T max -T current (1)

[0028] Rail vehicles at optimal speed v opt Or at a speed less than the optimal speed v opt The operating speed v thus results in a predictable friction element temperature T even when defined braking types (such as emergency braking, forced braking, or rapid braking) are applied. pred In particular, the maximum permissible friction element temperature T of at least one friction element of the friction brake is always less than or equal to that of the friction element itself. max .

[0029] As indicated above, the defined braking types include at least one of the following braking types: emergency braking, forced braking, rapid braking, and dangerous braking.

[0030] According to DIN EN 14478:2005-06, these braking types are defined as follows:

[0031] Rapid braking

[0032] A predefined braking force is applied using all available brakes, ensuring the required braking capacity and safety level. Braking capacity and the safety level of rapid braking, as described in vehicle-specific European standards (EN), are generally equal to or greater than the corresponding value of the maximum service braking (full braking), provided that the required force coordination and other necessary preconditions are met. In German, this concept can vary depending on the corresponding train type or traffic system and the type of rapid braking activation, as explained below:

[0033] Rapid braking is a rapid braking system triggered by the locomotive driver;

[0034] Dangerous braking refers to rapid braking in short-distance traffic braking systems.

[0035] Forced braking is rapid braking that is automatically activated by a signal or protection system (e.g., a train influence system);

[0036] Emergency braking is a rapid braking system triggered by passengers or train personnel by operating the emergency brake lever. The emergency brake lever is the operating interface for the passenger alarm system.

[0037] Maximum achievable service braking level with full braking

[0038] Safety braking is specifically designed for short-distance traffic braking systems, providing a higher level of safety than service braking and emergency braking. Braking capacity may be less than at maximum service braking or during emergency braking.

[0039] Service brakes apply a set braking force to regulate the speed of a train, including reducing speed, stopping, and temporary halting, and are the most commonly used type of braking.

[0040] As described above, the thermal state of at least one friction element can preferably be determined by the predictive friction element temperature T of at least one friction element. pred This indicates that the predictive temperature of the friction element is determined by the first temperature component T. current It consists of, in particular, the second temperature component ΔT, which is related to velocity, where,

[0041] a) Based on the current operating conditions of the rail vehicle, the predictive friction element temperature T is estimated or determined as a first influence. pred The first temperature component T current ,and

[0042] b) Define the first temperature component T of the rail vehicle. current and optimal speed v opt The functional relationship r between the predictive friction element temperature T and the temperature of the friction element is given by the relationship between the predictive friction element temperature and the temperature of the friction element. pred The second temperature component ΔT is considered as the second effect, and

[0043] c) Based on the first temperature component T current The relevant functional relationship r determines the optimal or maximum permissible speed v of the rail vehicle. opt .

[0044] The thermal state of the at least one friction element can also be determined by the predictive friction element temperature T of the at least one friction element. pred It means that, among them,

[0045] a) Estimate or determine the predictive friction element temperature T based on the current operating conditions of the rail vehicle. pred The first temperature component T current As the first influence, and

[0046] b) Estimate or determine the predicted friction element temperature T pred The second temperature component ΔT (especially speed-related) acts as a second effect, added to the first temperature component T when braking is virtually or theoretically performed with a defined braking type under the current operating conditions of the rail vehicle. current It appears on the at least one friction element, wherein,

[0047] c) The optimal or maximum permissible speed v of the rail vehicle opt The determination is made in the following manner, namely, by making the first temperature component T... current The sum of the second temperature component ΔT

[0048] c1) less than the maximum permissible temperature T of the friction element of at least one of the friction elements. max ,or

[0049] c2) is substantially equal to the maximum permissible temperature T of the at least one friction element. max .

[0050] Preferably, if in the current operating condition of the rail vehicle a) it is determined that the first temperature component T current The sum of the second temperature component ΔT and the second temperature component ΔT is less than the maximum permissible temperature T of the friction element. max During the current operating conditions, the current speed v of the rail vehicle is continuously increased until the current speed is substantially equal to the optimal speed v. opt Or if it is confirmed, or if

[0051] b) Determine the first temperature component T current The sum of the second temperature component ΔT and the second temperature component ΔT is greater than the maximum permissible temperature T of the friction element. max During the current operating conditions, the current speed v of the rail vehicle is continuously reduced until the current speed is substantially equal to the optimal or maximum permissible speed v. opt .

[0052] According to the improved scheme of this method, if the first temperature component T is determined... current The temperature of a friction element alone already exceeds the maximum permissible temperature T of the at least one friction element. max Then you can

[0053] a) Generate warning signals and / or diagnostic signals, and / or

[0054] b) Under the current operating conditions, continuously reduce the current speed v of the rail vehicle until the first temperature component T is reached. current The maximum permissible friction element temperature T is less than or equal to that of the at least one friction element. max .

[0055] The optimal speed v of the rail vehicle opt It is also possible

[0056] a) Automatic adjustment by means of a control device, said control device controlling or regulating the traction and / or braking of the rail vehicle, and / or

[0057] b) Displayed optically and / or acoustically on a display device.

[0058] The parameters characterizing the current operating status can be at least one of the following: the current speed of the rail vehicle, the current braking force, the current braking torque, the current braking pressure, the ambient temperature of the rail vehicle, the current load and / or load of the rail vehicle, the uphill or downhill gradient of the path traveled by the rail vehicle, and the service brake or maintenance brake with braking effect, wherein the braking effect is less than the braking effect in the defined braking type.

[0059] According to the improved scheme, the at least one friction element may include the brake disc and / or brake pads of the disc brake of the friction braking system, or the brake block and / or wheel working surface of the block brake unit of the friction braking system.

[0060] The defined braking type may also include at least one of the following braking types: emergency braking, forced braking, rapid braking, and dangerous braking.

[0061] According to the improved scheme, the rail vehicle may include a plurality of friction brakes, each having at least one friction element, wherein a locally optimal or maximum permissible speed v is determined for each of the plurality of friction brakes. _opt_local And as the optimal or maximum permissible speed v of the said rail vehicle opt Using the local optimal or maximum permissible speed v of multiple friction brakes _opt_local The minimum or lowest local optimal or maximum permissible speed v _opt_local_min .

[0062] Different methods can be used to merge:

[0063] - In the simplest case, as described above, the local optimal or maximum permissible speed v of multiple friction brakes is used. _opt_local The minimum or lowest local optimal or maximum permissible speed v _opt_local_min ;

[0064] - Additionally or alternatively, methods for eliminating statistical outliers are provided. For example, all values ​​for the locally optimal or maximum permissible velocity v. _opt_local The desired value can be sorted by a series of increasing values ​​and then averaged or taken from the minimum X percentage (where X is a predefined percentage). Attached Figure Description

[0065] Embodiments of the invention are presented in the accompanying drawings and explained in more detail in the following description. The accompanying drawings show:

[0066] Figure 1 A schematic diagram of an exemplary embodiment of a pneumatic friction braking device having a brake disc and a brake caliper having brake pads is shown;

[0067] Figure 2 A functional diagram showing an exemplary embodiment of an apparatus according to the invention for implementing the method according to the invention;

[0068] Figure 3A / B illustrates a flowchart of a method according to a preferred embodiment of the present invention;

[0069] Figure 4 The chart is shown, in which the following is presented: Figure 1 The predicted temperature T of the friction element of the friction brake pred The correlation between the second temperature component ΔT and the driving speed v and load state;

[0070] Figure 5 Show the speed v of the rail vehicle and Figure 1 The predicted temperature T of the friction element of the friction brake pred The first temperature component T current The functional relationship r between them. Detailed Implementation

[0071] exist Figure 1 The schematic depiction of a friction braking device on a rail vehicle is a pneumatic disc brake. This pneumatic disc brake includes a first friction element 1 and a brake caliper. The first friction element is implemented, for example, as a brake disc, supported on an axle of a wheel assembly (not shown) of the rail vehicle. The brake caliper has a second friction element 2, which includes two brake pads. Furthermore, the brake caliper has a brake cylinder 4 with a compressed air inlet 6, a piston 5, and a connecting rod 3. The piston 5 actuates the connecting rod 3, thereby pressing the brake pads, i.e., the second friction element 2, arranged on the connecting rod 3, against the brake disc, i.e., the first friction element 1. Compressed air from a compressed air system (not shown) of the rail vehicle is supplied to the piston 5, which actuates the connecting rod 3, via the compressed air inlet 6. The compressed air system includes components for controlling and regulating the friction braking device, such as a compressor, a brake controller, etc.

[0072] Used to determine the optimal or maximum permissible speed v of a rail vehicle opt The preferred embodiment of the device has in Figure 2The present invention includes a computing unit 7, in which a model is implemented, which performs thermal calculations according to the method according to the invention. Furthermore, the apparatus includes... Figure 2 The adjustment unit 8 presented in the middle influences the kinematic behavior of the rail vehicle based on the results of thermal calculations.

[0073] The relative compression of the first friction element 1 and the second friction element 2 causes braking of the rail vehicle. Here, a conversion occurs from the kinetic energy of the rail vehicle to heat, thereby causing the temperature of the first friction element 1 and the second friction element 2 to rise. The disengagement of the first friction element 1 and the second friction element 2 causes a reduction or cancellation of braking of the rail vehicle. This, along with the effects of known heat transfer principles, lowers the temperature in the first friction element 1 and the second friction element 2, i.e., cools the first friction element 1 and the second friction element 2. The described temperature behavior is calculated or estimated by means of the method according to the invention, and then the optimal or maximum permissible speed v is determined in the calculation unit 7 based on this temperature behavior. opt .

[0074] The device includes a vehicle speed sensor 10 for detecting vehicle speed v, and a braking force F for detecting braking pressure p. B Brake pressure sensor 11, used to detect ambient temperature T u An ambient temperature sensor 12, a time measuring instrument 13 for detecting absolute time t, and a load braking device 14 are connected to the computing unit 7 via corresponding data lines to provide sensor signals to the model. A travel speed sensor 10, a brake pressure sensor 11, and an ambient temperature sensor 12 are arranged in the chassis of the rail vehicle (not shown). However, it is also conceivable that the travel speed v and the brake pressure p are read into the computing unit 7 from the rail vehicle's data bus system. Furthermore, it is also conceivable that the brake pressure p is approximately determined by the deceleration and the mass to be braked. Here, the deceleration is obtained, for example, by differential calculation of the travel speed v or by an acceleration sensor, and the mass to be braked m is determined by the load braking device 14. Furthermore, it is also conceivable that the angular velocity or wheel speed of the wheel is detected instead of the travel speed v, and thermal calculations are performed using this angular velocity or wheel speed. In addition, the configuration data of the rail vehicle is stored in the memory of the computing unit 7 (not shown here), and is also available for use by the model. The memory also stores, for example, the maximum allowable friction element temperature T of the first friction element 1. max .

[0075] The time measuring instrument 13 and the calculation unit 7 are implemented in a controller not shown, but arranged in a carriage not shown. The calculation unit 7 receives data on the driving speed v from the driving speed sensor 10 and data on the braking pressure p or braking force F from the braking pressure sensor 11 via corresponding data lines. B Data received from ambient temperature sensor 12 regarding ambient temperature T u The system receives data on vehicle mass m from the load braking device 14 and data on absolute time t (timestamp) from the time measuring instrument 13, and performs calculation operations accordingly according to the method of the invention. Furthermore, the configuration data of the rail vehicle stored in the memory of the calculation unit 7 can also be added to the model's calculation operations.

[0076] Here, for example, considering the travel speed v and braking force F of the rail vehicle... B Ambient temperature T u Given absolute time t, quality m, and configuration data, based on the target Figure 3A and Figure 3B The description of the search is in Figure 1 The thermal state of the friction braking device, especially its first friction element 1, is presented in the image.

[0077] The calculation unit 7 is connected via a corresponding data line to an adjustment unit 8, implemented in the vehicle control unit (not shown), located within the car. The adjustment unit 8 influences the kinematic behavior of the rail vehicle in such a way that, for example, the rail vehicle maintains, automatically brakes, or accelerates its current speed v by means of signals generated in the model implemented in the calculation unit 7 due to thermal calculations and transmitted to the adjustment unit 8. In particular, the adjustment unit 8 sets or adjusts the optimal speed v. opt Braking can preferably be achieved by controlling traction to avoid increasing the temperature and wear of the brake discs due to the action of the disc brakes. This allows for the control of the thermal state of the disc brakes on rail vehicles.

[0078] Furthermore, a display unit 9, connected to the computing unit 7 via signal lines, is arranged in the driver's cab (not shown) of the rail vehicle. On this display unit, based on thermal calculations according to the method of the invention described further below, the desired prompts or warnings, especially the optimal speed v, are displayed to the locomotive driver. opt Therefore, it is also possible to monitor the thermal state of friction brakes or disc brakes.

[0079] It is also possible to use the display unit 9 to additionally display speed limits, permissible deceleration, or permissible driving characteristics (the time sequence of acceleration and deceleration segments and the phases with constant driving speed v or a stationary state).

[0080] To warn the rail vehicle of adverse kinematic behavior in relation to the thermal state of the friction brake, acoustic and / or optical signals may be additionally output to the locomotive driver via the audio output device of the display unit 9.

[0081] Here, different implementation schemes and arrangements of the driving speed sensor 10, braking force sensor 11, ambient temperature sensor 12, time measuring instrument 13, display unit 9, calculation unit 7, load braking device 14, and adjustment unit 8 can be envisioned. For example, it is conceivable that... Figure 2 As shown, the calculation unit 7 and the adjustment unit 8 are arranged separately, or the calculation unit 7 and the adjustment unit 8 are integrated into a single structural unit.

[0082] Furthermore, it is conceivable that, for example, the computing unit 7 is arranged in the control console and communicates with the rail vehicle via radio signals, that is, for example, receiving information about its travel speed v, and sending instructions based on the thermal calculations performed according to the invention to limit the travel speed v to the maximum permissible or optimal travel speed v. opt The instructions above.

[0083] Figure 3A and Figure 3B A flowchart illustrating a preferred embodiment of the method according to the invention is shown, the method being used to determine the optimal or maximum permissible speed v of a rail vehicle based on the thermal state of a first friction element 1, for example, in the form of a brake disc of a disc brake. opt Here, it is clear that... Figure 1 The disc brakes shown represent only one or all disc brakes of the rail vehicle. In particular, thermal monitoring of one or all disc brakes is used to determine the optimal or maximum permissible speed v of the rail vehicle. opt .

[0084] Therefore, in step 100, parameters characterizing the current operating status of the rail vehicle are detected. These parameters include, for example, the current travel speed v and the current braking force F. B Current ambient temperature T u Data regarding absolute time t (timestamp), the current mass m of the rail vehicle, and the configuration data of the rail vehicle.

[0085] Then, in the model of calculation unit 7, in step 200, for example, based on the current operating conditions of the rail vehicle described above, the predictive friction element temperature T of the first friction element 1 is calculated or estimated. pred The first temperature component T current Alternative or additional sites, the first temperature component T current It can also be measured directly using a temperature sensor. The first temperature component, T... currentThen, for example, a surface temperature calculated or estimated by a model, which is set on the surface of the first friction element 1 based on the actual current driving conditions.

[0086] In the subsequent step 300, the first temperature component T is then examined in the model. current Is it greater than the maximum permissible temperature T of the first friction element 1? max If this is the case ("yes"), problem handling is performed. For example, the calculation unit 7 generates an alarm or warning signal, which is then output to the display unit 9, for example, optically, and the alarm or warning signal indicates, for example, or contains an indication of the critical thermal state of the first friction element 1. Alternatively or additionally, an influence signal may also be generated, which is output to the adjustment unit 8, which controls or adjusts the traction and / or braking of the rail vehicle. With the aid of the influence signal, the travel speed v and / or deceleration a of the rail vehicle decreases, for example, until the first temperature component T is reached. current The maximum allowable temperature T of the first friction element 1 is less than or equal to that of the first friction element 1. max Additionally, diagnostics can also be performed, for example, to determine whether the continuous wear of a disc brake has resulted in a relatively high temperature.

[0087] However, if this is not the case ("No"), then in step 400 the maximum permissible or optimal speed V of the rail vehicle is determined by means of a behavioral model implemented in the calculation unit 7 for, for example, each friction brake (referred to there as a braking unit). _opt_local In the case of a defined braking type, such as virtual braking in the form of emergency braking, the temperature T of the first friction element 1 substantially or precisely has or reaches the maximum permissible friction element temperature T of the first friction element 1. max .

[0088] Therefore, different approaches are possible. As already indicated at the beginning, if the rail vehicle virtually brakes with a defined braking type during the current operating conditions, a predictable friction element temperature T will (theoretically) occur on the first friction element. pred For example, the surface temperature of the first friction element 1. Therefore, the predictive friction element temperature T pred It is a type of "prediction" of the temperature of the first friction element 1, which the first friction element has when the rail vehicle is theoretically or virtually braking with a defined braking type.

[0089] Therefore, this predictive friction element temperature T pred It can basically be determined as the first temperature component T current The sum of the second temperature component or temperature variable ΔT:

[0090] T pred = T current +ΔT (2)

[0091] Predictive friction element temperature T pred The second temperature component ΔT thus represents a temperature component that is set on the first friction element 1 solely due to virtual braking with a defined braking type. Therefore, when braking is performed virtually or theoretically with the defined braking type under the current operating conditions of the rail vehicle, the temperature component T is added to the first temperature component. current A second temperature component ΔT will be set on the surface of the first friction element 1. This defined braking type may not be required or has not yet been required in the current driving operation, but may be required in the current driving operation.

[0092] Predictive friction element temperature T pred The second temperature component ΔT depends in particular on the driving speed v, which exists at time point t (time stamp) under the current driving conditions. Figure 4 A graph is shown, stored in the calculation unit 7, for example, as a family of characteristic curves, in which the correlation between the second temperature component ΔT and the driving speed v is presented for different load conditions defined in generally known valid specifications, such as AW1: low load; AW2: average load; and AW3: high load. Of course, other load conditions can also be considered in the family of characteristic curves. As can be seen, as the driving speed v, which also characterizes the current driving operation, increases, the second temperature component ΔT also increases. Therefore, through... Figure 4 The chart, presented as a family of characteristic curves, predicts the temperature T of the friction element. pred The second temperature component ΔT is assigned to the travel speed v and load of the rail vehicle in the current operating conditions.

[0093] However, preferably, the second temperature component ΔT is not explicitly defined in this method. As mentioned above, the second temperature component or temperature variable ΔT can be used as a "temperature reserve," which corresponds to the maximum permissible friction element temperature T of the first friction element 1 here. max and the first temperature component T current The difference between them:

[0094] ΔT = T max - T current (3)

[0095] Rail vehicles at optimal speed v opt Or at a speed less than the optimal speed v optThe speed v of operation should therefore result in a predictable friction element temperature T even when the defined braking type (such as emergency braking, forced braking, or rapid braking) is applied. pred In particular, the maximum permissible friction element temperature T of at least one friction element of the friction brake is always less than or equal to that of the friction element. max .

[0096] Therefore, in this method, it is preferable to define or determine in Figure 5 The first temperature component T in the rail vehicle is presented in the data. current and optimal speed v opt The functional relationship r between them, in which the predictive friction element temperature T has been taken into account, has been established. pred The second temperature component ΔT. Then, based on the first temperature component T... current The relevant functional relationship r determines the optimal speed v of the rail vehicle. opt .

[0097] According to Figure 5 In the illustrated example, the rail vehicle travels at a speed of 56 km / h, and Figure 1 The first temperature component T of the brake disc 1 of the disc brake current Here the temperature is 300°C, and the brake disc is used, for example, as a first friction element. This first temperature component T... current This can be measured, for example, by means of a temperature sensor. Alternatively or additionally, the first temperature component can also be estimated or calculated from other parameters by means of a model implemented in computing unit 7.

[0098] In this case, the temperature variable or second temperature component ΔT generated by the virtual emergency braking corresponds to... Figure 5 The maximum permissible temperature T of the friction element is indicated by the dashed line. max The interval of the curve or function Γ. At speed v = 56 km / h and T current At 300℃, the temperature variable or second temperature component ΔT is approximately 30℃, which is in Figure 5 The middle is marked as ΔT EB_low Therefore, the current speed v = 56 km / h included in the current driving conditions is too small, thus the maximum permissible friction element temperature T is reached on brake disc 1 under the assumed hypothetical emergency braking condition. max =400℃.

[0099] This means that, considering only the thermal load capacity of brake disc 1, the rail vehicle can travel faster than at the current speed v = 56 km / h.

[0100] Regarding the optimal or maximum permissible speed v for the thermal load capacity of brake disc 1 opt Then you can Figure 5 The chart shows that the method is to determine the current driving speed (v = 56 km / h, T...). current = 300°C) Start from and extend a vertical line upwards.

[0101] Then, at the intersection of the vertical line and the function Γ, there exists the running status or running point of the rail vehicle, and at this running status or running point, the predictive temperature T pred Equal to the highest permissible temperature T of the friction element max The second temperature component ΔT equals 100℃ at this intersection point, and... Figure 5 The middle is represented as ΔT EB_opt Therefore, in the vertical direction, the optimal or maximum permissible speed v opt_lokal Located at this intersection, the speed is, for example, 100 km / h. That is to say, only with respect to the disc brake under consideration, the rail vehicle can travel at v = 100 km / h at the "thermal limit" without exceeding the maximum permissible friction element temperature T of the brake disc 1 of the disc brake through a virtual emergency braking. max .

[0102] However, for the speed range v > 100 km / h, the predictive temperature T pred The maximum permissible friction element temperature T greater than that of brake disc 1 max (T) pred > T max Then, it falls within the thermal critical range. The second temperature component ΔT is too large in this range and... Figure 5 The middle is represented as ΔT EB_high Therefore, the speed v of the rail vehicle must be reduced either by the locomotive driver (who displays the emergency situation on the display unit 9) and / or automatically by the adjustment unit 8, and more precisely, in the best case, reduced to a maximum v = 100 km / h.

[0103] Therefore, the curve or function Γ already includes the effect of virtual braking under the braking type "emergency braking", and thus already includes the effect of the second temperature component or temperature variable ΔT on the brake disc. Therefore, each of the above-mentioned braking types under consideration forms its own curve or function Γ, and is stored, for example, as a characteristic curve in the calculation unit 7.

[0104] Therefore, at the "thermal limit," the optimal or maximum permissible speed v is... opt The optimal utilization of the thermal load capacity of the brake disc 1 of the driving-permitted disc brake is achieved under the following conditions: even under simulated braking, the maximum permissible friction element temperature T of the brake disc 1 shall not exceed [the specified value]. maxThis optimization is also achieved by considering the train's actual load rather than its maximum allowable load. Despite the aforementioned temperature control methods, the operating schedule must always be followed, meaning the train cannot arrive at stations faster than usual. However, the accumulated delays can be compensated for by traveling between stations more quickly.

[0105] It's not always necessary to use the optimal speed v opt Driving. What may be sufficient for the operators of rail vehicles is that the brake discs never enter the critical temperature range in the train, meaning that slower driving is also acceptable.

[0106] Preferably, not only for disc brakes, but for example for multiple or all disc brakes on a rail vehicle, the optimal local temperature v is then determined separately. opt_lokal The term "locally" refers to the location of the corresponding disc brake in the rail vehicle.

[0107] Then, in step 500, the local optimal temperature v of the disc brake is determined. opt_lokal The standard-based evaluation and the optimal speed v are combined into a range of rail vehicles or trains. opt .

[0108] For example, to achieve a merging effect, the local optimal speed v of all disc brakes can be considered. _opt_local The minimum or lowest local optimal velocity v _opt_local_min The optimal speed v for rail vehicles opt .

[0109] Then, this optimal speed can be displayed to the locomotive driver on display unit 9 in step 600. Additionally, when the critical temperature range of the disc brake is reached, a warning or alarm signal can be displayed on display unit 9, for example. The current highest temperature of the relevant disc brake, such as the current highest predicted temperature T, can also be displayed periodically, for example. pred and / or the highest first temperature component T current And the positioning of the relevant disc brakes. Finally, it is also conceivable to periodically display the corresponding optimal speed v of the rail vehicle. opt .

[0110] Attached to or alternative to step 600, the current speed v can be adjusted to the desired optimal speed v in step 700 via the adjustment unit 8. opt superior.

[0111] It should be understood that the above method can also be used for brake pads and for any type of friction brake, but not for the brake disc of a disc brake.

[0112] List of reference numerals

[0113] 1 First friction element

[0114] 2 Second friction element

[0115] 3-link

[0116] 4 brake cylinders

[0117] 5-piston

[0118] 6 Compressed air interfaces

[0119] 7 Calculation Units

[0120] 8 adjustment units

[0121] 9 display units

[0122] 10 driving speed sensors

[0123] 11 Brake pressure sensor

[0124] 12 Ambient Temperature Sensor

[0125] 13 Time measuring instrument

[0126] T current First temperature component

[0127] ΔT second temperature component

[0128] T pred Predictive friction element temperature

[0129] T max Maximum permissible temperature of friction elements

[0130] V opt Optimal or maximum permissible driving speed

[0131] V _opt_local Local optimal or maximum permissible driving speed

[0132] Γ at the optimal speed v opt The first temperature component T of the predictive friction element temperature current Functional relationship between

Claims

1. A method for determining the optimal or maximum permissible speed of a rail vehicle based on the thermal state of at least one friction element (1, 2) of at least one friction brake of the rail vehicle. The method, the method comprising at least the following steps: a) Detect at least one parameter characterizing the current operating status of the rail vehicle. b) Determine or estimate the first impact on the thermal state of the at least one friction element (1, 2) based on the current operating conditions of the rail vehicle. c) Determine or estimate a second effect on the thermal state of the at least one friction element (1, 2), which, when braking is virtually or theoretically performed with a defined braking type in the current operating conditions of the rail vehicle, affects the thermal state of the at least one friction element (1, 2) in addition to the first effect. d) The optimal or maximum permissible speed of the rail vehicle It is determined that, under the first influence and under the second influence, the at least one friction element (1, 2) is subjected to such influence. d1) The maximum permissible temperature (T) of the friction element (1, 2) shall not exceed that of the at least one friction element (1, 2). max ),or d2) The maximum permissible friction element temperature (T) of at least one of the friction elements (1, 2) occurs. max ) The method is characterized by comprising at least the following additional steps: e) The rail vehicle includes a plurality of friction brakes, each of the plurality of friction brakes having at least one friction element (1, 2), and a local optimal or maximum permissible speed is determined for each of the plurality of friction brakes. And the optimal speed or maximum permissible speed at the local area of ​​the plurality of friction brakes. The optimal or maximum permissible speed in the smallest local area is considered below. As the optimal or maximum permissible speed for rail vehicles .

2. The method according to claim 1, characterized in that, The thermal state of the at least one friction element (1, 2) is determined by the predictive friction element temperature (T) of the at least one friction element (1, 2). pred This indicates that the predictive friction element temperature includes a first temperature component (T). current ) and the second temperature component (ΔT), where, Based on the current operating conditions of the rail vehicle, the temperature of the predictive friction element (T) is estimated or determined. pred The first temperature component (T) current ) as the first influence, and Defined in the first temperature component (T) of the rail vehicle current and optimal or maximum permissible speed The functional relationship (r) between them, in which the predictive friction element temperature (T) is expressed. pred The second temperature component (ΔT) is considered as the second effect, and Based on the first temperature component (T) current The relevant functional relationship (r) is used to determine the optimal or maximum permissible speed of the rail vehicle. .

3. The method according to claim 1, characterized in that, The thermal state of the at least one friction element (1, 2) is determined by the predictive friction element temperature (T) of the at least one friction element (1, 2). pred ) indicates that, The predictive friction element temperature (T) is estimated or determined based on the current operating conditions of the rail vehicle. pred The first temperature component (T) current ) as the first influence, and Estimate or determine the predictive friction element temperature (T) pred The second temperature component (ΔT) acts as a second effect, added to the first temperature component (T) when braking is virtually or theoretically performed under the defined braking type during the current operating conditions of the rail vehicle. current ) appears on at least one friction element (1, 2), wherein, The optimal or maximum permissible speed (v) of the rail vehicle opt ) is determined to be such that the first temperature component (T) current The sum of the first and second temperature components (ΔT) is less than the allowable maximum temperature (T) of the friction element (1, 2). max ), or equal to the maximum permissible friction element temperature (T) of at least one friction element (1, 2). max ).

4. The method according to claim 2 or 3, characterized in that, If it is determined from the current operating status of the rail vehicle: From the first temperature component (T) current The sum of the first and second temperature components (ΔT) is less than the maximum permissible temperature of the friction element (T). max Therefore, in the current operating conditions, the current speed of the rail vehicle will be continuously increased. until the current speed equals the optimal or maximum permissible speed of the rail vehicle. ,or From the first temperature component (T) current The sum of the first and second temperature components (ΔT) is greater than the maximum permissible temperature of the friction element (T). max Therefore, in the current operating situation, the current speed of the rail vehicle will be continuously reduced. until the current speed equals the optimal or maximum permissible speed of the rail vehicle. .

5. The method according to claim 2 or 3, characterized in that, If the first temperature component (T) is determined current The temperature of a friction element alone is already greater than the maximum allowable temperature (T) of at least one friction element (1, 2). max ), Generate warning signals and / or diagnostic signals, and / or The current speed of the rail vehicle is continuously reduced under the current operating conditions. until the first temperature component (T) current The allowable maximum temperature (T) of the friction element is less than or equal to that of the at least one friction element (1, 2). max ).

6. The method according to any one of claims 1 to 3, characterized in that, The optimal or maximum permissible speed of the rail vehicle Automatic adjustment is achieved by means of a control device, which controls or regulates the traction and / or braking of the rail vehicle, and / or Displayed optically and / or acoustically on a display device.

7. The method according to any one of claims 1 to 3, characterized in that, The parameter characterizing the current operating status is at least one of the following parameters: the current speed of the rail vehicle, the current braking force, the current braking torque, the current braking pressure, the ambient temperature of the rail vehicle, the current load and / or load of the rail vehicle, the uphill or downhill gradient of the path traveled by the rail vehicle, and maintenance braking or service braking with braking effect, wherein the braking effect is less than the braking effect in the defined braking type.

8. The method according to any one of claims 1 to 3, characterized in that, The at least one friction element (1, 2) comprises the brake disc and / or brake pads of a disc brake in a friction braking system, or the wheel working surface and / or brake block of a block brake unit in a friction braking system.

9. The method according to any one of claims 1 to 3, characterized in that, The first effect on the thermal state of the at least one friction element (1, 2) is estimated by means of a model based on the current operating conditions of the rail vehicle and / or determined by sensor signals from the sensor device of the rail vehicle.

10. The method according to any one of claims 1 to 3, characterized in that, The defined braking types include at least one of the following braking types: emergency braking, forced braking, rapid braking, and dangerous braking.

11. The method according to any one of claims 1 to 3, characterized in that, The rail vehicle includes multiple friction brakes, each having at least one friction element (1, 2), and a local optimal or maximum permissible speed is determined for each of the multiple friction brakes. Furthermore, the optimal or maximum permissible speed of the rail vehicle, derived from the locally optimal or maximum permissible speed according to the determined criteria, is taken as the optimal or maximum permissible speed of the rail vehicle. .

12. The method according to any one of claims 1 to 3, characterized in that, The current speed of the rail vehicle Adjust to the optimal or maximum permissible speed of the rail vehicle. .

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