System for diagnosing and monitoring air supply systems and their components

Abstract

Featuring a system for diagnosing and monitoring air supply systems: a compressor (1) configured to provide compressed air, and an air dryer configured to remove moisture from the compressed air in the system, characterized in that the system further comprises: at least two sensors (2), wherein one sensor (2) is configured and arranged to detect a status signal of a component to be monitored, and another sensor (2) is configured and arranged to detect a reference signal with respect to the component to be monitored, an evaluation unit (3) configured to evaluate the signals of the sensors (2) by comparing the status signal and the reference signal, wherein the evaluation unit (3) is further configured to convert the sensor signals into maintenance and / or control signals using an evaluation logic, which control the operating mode of the air supply system, and wherein the sensors (2) are configured and arranged to determine the temperature at the cooling air inlet as a reference signal and a component temperature or an oil temperature as a status signal, and / or the temperature of the air at the process inlet as a reference signal and the component temperature or the oil temperature as a status signal, and / or the intake pressure as a reference signal and the intermediate pressure or the final pressure as a status signal, and / or the air temperature as a reference signal and the pressure dew point as a status signal based on the measured values ​​of humidity and the temperature of the air in the compressor.

Description

[0001] The invention relates to a system for diagnosing and monitoring air supply systems and their components.

[0002] For monitoring the condition of air supply systems, and in particular their compressors in pneumatic braking systems for rail vehicles, state-of-the-art technology typically uses only a few individual sensors or switches. These include, for example, oil temperature sensors or sensors for monitoring the air outlet temperature.

[0003] These components generally serve to ensure compliance with a maximum limit, which is usually safety-relevant. These limits are typically maximum temperature values ​​for the oil temperature or the component temperature itself. The evaluation logic corresponding to the sensors is generally one-dimensional, meaning that a sensor reading is compared against the relevant maximum limit, and if the limit is exceeded, an emergency shutdown of the system is triggered.

[0004] A disadvantage of this approach is that it doesn't provide genuine condition monitoring of the functionality of any component(s) in an air supply system. It can only be determined that the function cannot be performed correctly if a limit value is exceeded, triggering an emergency shutdown. However, no conclusions can be drawn about the system's operation prior to the failure or about the specific fault. Therefore, to prevent failures, maintenance must be performed at fixed intervals. This can lead to situations where frequent maintenance is carried out prematurely, even on components that don't yet require servicing. This approach must therefore be considered uneconomical.

[0005] Another disadvantage is that, due to the constantly tightening specification requirements for technical systems, such as guidelines on noise emissions, energy efficiency, or similar factors, compliant operating modes of the systems must be enabled and ensured. This is currently not possible based on the existing condition monitoring system.

[0006] In this context, DE 10 2014 113 371 A1 relates to a method for monitoring and diagnosing components of a railway vehicle with regard to the necessary repair or maintenance of at least one component, in which at least one measuring device records at least one measured variable that is relevant for assessing the necessary repair or maintenance of the component, and in which evaluation software implemented in an evaluation device arranged on board the railway vehicle evaluates the recorded measured variable with regard to the necessary repair or maintenance of the component in question, whether required immediately or in the future.

[0007] DE 11 2013 002 118 T5 relates to a diagnostic procedure for a compressor in which, among other things, a compressor is operated to compress air from a first-stage compressor for an intermediate-stage reservoir, air from the intermediate-stage reservoir is supplied to a second-stage compressor and the air is further compressed in the second-stage compressor for a primary reservoir, an intermediate-stage pressure in the intermediate-stage reservoir is monitored and the condition of the compressor is identified by detecting a change in the monitored intermediate-stage pressure during a period in which the compressor is in operation.

[0008] It is therefore an object of the present invention to provide a system for the diagnosis and monitoring of air supply systems, which increases their reliability and enables needs-based maintenance intervals for a more economically sensible operation.

[0009] This problem is solved by the system according to the independent claim. Advantageous embodiments of the invention are the subject of the dependent claims.

[0010] This task is solved in particular by a diagnostic system for air supply systems, which makes it possible to record changes in the condition and function of an air supply system and its components, in order to select optimal operating modes based on this information in order to maintain the function of the overall system on the one hand and to meet external specification requirements on the other.

[0011] With the information gained, it is therefore also possible to organize maintenance intervals not rigidly, but to base them on the condition of the individual components and only carry them out when necessary.

[0012] The system according to the invention comprises a compressor for providing compressed air to the system, an air dryer to remove moisture from the compressed air, at least two sensors, wherein one sensor detects a status signal of the air supply system and the other sensor detects a reference signal, and an evaluation unit for evaluating the data detected by the sensors, wherein the evaluation unit is further configured to convert the sensor signals into maintenance and / or control signals using an evaluation logic, which in turn control the operating mode or the maintenance interval of the air supply system.

[0013] In an advantageous embodiment of the invention, the sensors detect component and process variables such as a cooling air temperature, an intake temperature, a cylinder wall temperature of a cylinder of the compressor, an oil temperature, an outlet temperature, the final pressure and / or the intake vacuum, depending on the type of compressor, in order to perform condition monitoring and control of a compressor inverter on the basis of these parameters, which sets a frequency and an amplitude of the voltage applied to the compressor and thus the operating parameters of the compressor.

[0014] According to the invention, the sensors detect the temperature at the cooling air inlet as a reference signal and a component temperature, such as the temperature of a cylinder wall of the compressor or an oil temperature, as a status signal, and / or the temperature of the air at the process inlet as a reference signal and the component temperature, air temperature at the outlet or the oil temperature as a status signal, and / or the intake pressure as a reference signal and the intermediate pressure or a final pressure after the last compressor stage as a status signal, and / or the air temperature as a reference signal and the pressure dew point as a status signal based on the measured values ​​of humidity and the temperature of the compressed process air in the compressor.

[0015] Furthermore, in an advantageous embodiment, the invention includes a data transmission unit that transmits the sensor data, already evaluated in a first stage on the vehicle side (i.e., located in the vehicle), along with other relevant vehicle information, to a data processing device located off-road (i.e., not in the vehicle), so that the data can be further evaluated there. In this embodiment, the data processing thus takes place sequentially in multiple stages. Depending on the type and complexity of the evaluation, different tasks can therefore be performed by different devices.

[0016] One advantage of multi-stage analysis is that the vehicle-side evaluation unit only requires comparatively low processing power. The processing power of a central evaluation unit, on the other hand, is easier to expand if needed. Furthermore, it allows for the consideration of additional data not accessible within the vehicle itself, such as data from other vehicles, thus enabling a more comprehensive analysis. For example, a central, roadside evaluation unit can compare similar vehicle configurations worldwide. This allows the central evaluation unit to learn from other vehicles or vehicle fleets for the specific analysis case, should similar problems occur generally but are unknown to the individual vehicle. Consequently, a significantly larger amount of data is available for the analysis, enabling the detection of potential errors in advance.

[0017] In the advantageous embodiment described in the previous paragraph, the pathside device for data processing is considered part of the system and includes at least one database and / or a web server.

[0018] In the advantageous embodiment described in the two paragraphs above, communication preferably takes place via WLAN and / or mobile communications in order to ensure rapid data exchange that functions over greater distances.

[0019] In another advantageous embodiment, the pathside device is configured to be able to store the data from different vehicles long-term and has an output unit to be able to output the data to operators in a collected format.

[0020] In a further advantageous embodiment, the sensors and the vehicle-side evaluation unit are arranged in a CAN bus network, with the evaluation unit acting as the bus master, or in an Ethernet network. If necessary, the sensors have signal converters that convert the signals so that they can be transmitted in the respective network. The sensor signals are preferably carried from the sensors to the evaluation unit via shielded cables.

[0021] Furthermore, in another advantageous embodiment, the system features signal converters at the points where a signal needs to be converted. These converters, for example, convert the sensor signals for transmission to the evaluation unit or to the path-side data receiving unit. If signals need to be converted more frequently for transmission between different components of the system, several signal converters are provided accordingly. These can already be integrated into the sensors.

[0022] In a further advantageous embodiment of the invention, the system is implemented in the central brake control unit. The evaluation unit thus has access to additional diagnostic and control signals from the vehicle, such as data from the frequency converter of the air supply system compressor, weather data, or information about the current vehicle operation.

[0023] One embodiment of the invention is explained in more detail below with reference to the two figures. Fig. Figure 1 shows a schematic representation of an embodiment of the invention, wherein the representation is limited to the monitoring of the compressor of an air supply system. Fig. Figure 2 shows an embodiment of a possible arrangement of sensors for monitoring the compressor of an air supply system.

[0024] Sensors 2 in Fig. 1. The sensors record the operationally relevant temperatures and pressures of compressor 1. Some of the sensors determine compressor 1's status signals, such as cylinder wall temperature, oil temperature, intermediate pressure between two compressor stages, final pressure after the last compressor stage, or indirectly, a pressure dew point based on the measured values ​​of humidity and air temperature within the compressor. Other sensors record parameters whose measurement signals serve as reference signals. These include, for example, the ambient air temperature, intake air temperature, cooling air temperature, and intake pressure. The sensor system is designed so that a reference signal of the same type is recorded for each status signal. A single reference signal can also serve as a reference for multiple status signals.

[0025] A description of an exemplary arrangement of a selection of sensors is given below. Fig. 2 explained.

[0026] Furthermore, an evaluation unit 3 is provided, which evaluates the signals acquired by the sensors 2. The sensors 2 and the evaluation unit 3 are arranged in a CAN bus network (not shown), with the evaluation unit 3 acting as the CAN bus master. To transmit the sensor data, the signals are converted into CAN bus signals by signal converters.

[0027] In evaluation unit 3, simple evaluation processes can be performed, such as comparisons between a status signal and a reference signal, or comparisons between a status signal and a corresponding maximum value. The results of these comparisons, along with all vehicle-relevant data, or rather all acquired sensor signals, are transmitted to a data transmission unit 4.

[0028] This unit forwards the data either to a control unit 10 of an air supply system or to a data receiving unit 5 on the path side. The control unit 10 processes the information into control commands for the air supply unit and thus for the compressor 1, enabling changes in the operating mode of the compressor 1 to be implemented by controlling an inverter 13 of the compressor 1. Furthermore, the evaluation unit 3 can also access internal signals from an inverter monitoring system, such as the inverter temperature and current consumption. This allows for a quick and immediate response to unforeseen situations and the derivation of consequences for the operating behavior.

[0029] By integrating the control unit into a complete train control system, signals from the diagnostic device can be overridden by signals from the train control system in the event of an unavoidable emergency operation. This allows for signal weighting within the control unit.

[0030] By transmitting the data to a data receiving unit 5 of a pathside device for data processing (14), the data can also be stored in a database in the long term and, in the present embodiment, made accessible to different users via a web server 7.

[0031] Furthermore, the data from the data receiving unit 5 is transferred to a central, roadside evaluation unit 8. This unit also has a connection to the database of the web server 7 and thus access to additional information not recorded by the vehicle's sensors. Using this additional information and easily expandable computing power, for example in a data center, a more comprehensive analysis of the data can be performed.

[0032] The results of this evaluation are then output to the users via an output unit 9 of the pathside device for data processing (14) or sent back to the control unit 10 via a receiver unit integrated in the control unit 10, which in turn causes a change in the operating strategy of the compressor 1.

[0033] For example, if the system detects that there is a risk of exceeding the maximum temperature of a cylinder of a piston compressor or the oil temperature of a screw compressor, the control unit 10 can reduce the speed of the compressor so that the further temperature input into the system is reduced and the permissible temperatures are maintained and a minimum required system pressure can still be ensured.

[0034] In compressors where low air demand prevents the operating temperature from being reached, thus increasing the risk of compressor damage from water accumulation in the oil, the combination of compressor monitoring and control unit allows for an increase in compressor speed. This operates the compressor at the upper permissible pressure level, allowing the increased temperature required for water evaporation to be reached more quickly. Simultaneously, a valve opens to prevent further pressure increases within the vehicle itself, enabling the water to escape from the system as quickly as possible in the form of steam. Therefore, by increasing the speed, the risk of compressor damage from water accumulation in the oil can be eliminated more rapidly than with lower speed operation.Similarly, the cooling capacity of the electric fans for cooling the compressor or inverter can be increased or decreased as needed. This allows both operational and external influences to be specifically identified and appropriate countermeasures to be taken.

[0035] It should be noted that in other embodiments the evaluation of the sensor data can take place exclusively on the vehicle side, i.e. in the vehicle itself, or exclusively on the road side, i.e. outside the vehicle.

[0036] Fig.Figure 2 shows a possible arrangement of various sensors for monitoring a compressor 1 of an air supply system. In the illustrated embodiment, the compressor 1 is a two-stage piston compressor with two cylinder heads 1a and 1b on one side and another cylinder head on the other. A fan 11, which cools the cylinders 1 with ambient air, is located directly next to the compressor cylinders on one side. An air intake box 12 of the compressor 1 is shown on the other side. The cylinders are driven by a motor located at the opposite end from the compressor's fan 11. On the side with one cylinder, there is a low-pressure cylinder, which is difficult to discern from the perspective shown. On the side with two cylinders, the smaller, front cylinder on the fan side is a high-pressure cylinder (1b), and the rear, motor-side cylinder is also a low-pressure cylinder (1a).

[0037] Looking at the radiator from the front, it is horizontally divided. The lower section contains the pressure from the first compression stroke by the two low-pressure cylinders (intermediate pressure), while the upper section contains the pressure after the second compression stroke (system pressure, final pressure).

[0038] A temperature sensor located directly in front of the fan 11 measures the temperature of the ambient air immediately before it enters the fan 11. This ambient air temperature thus represents the cooling air temperature T1 of the system. Another temperature sensor measures the temperature T2 at the cylinder wall 1b. Finally, a third temperature sensor measures the temperature of the compressed air after it exits the compressor and before it enters an air dryer (not shown). The hose 13 connects the compressor 1 to the air dryer. This temperature is therefore the air dryer inlet temperature T3.

[0039] A pressure sensor in the air intake box 12 measures the intake vacuum p1, while another pressure sensor in the intermediate circuit between the two compressor stages of the two-stage piston compressor measures the intermediate circuit pressure p2. Analogous to the measurement of the air dryer inlet temperature T3, a third pressure sensor measures the final pressure p3 after the air exits the compressor and before entering the air dryer (not shown).

[0040] Based on these measurement signals, pairs of values ​​consisting of a status signal and a reference signal can be generated for monitoring compressor 1. The air intake temperature T1 can serve as the reference signal, and the cylinder wall temperature T2 and the air dryer inlet temperature T3 as status signals. Similarly, the intake vacuum p1 can be defined as the reference signal, and the intermediate circuit pressure p2 or the final pressure p3 as the status signal. REFERENCE MARK LIST 1 compressor 1a Cylinder head compressor stage a 1b Cylinder head Compressor stage b 2 Sensor 3 (vehicle-side) evaluation unit 4 Data transmission unit 5 Data receiving unit 6 Database 7 Web servers 8 (pathside) evaluation unit 9 output units 10 Control unit 11 fans 12 Air intake box 13 hose T1 Cooling air temperature T2 Cylinder wall temperature T3 Air dryer inlet temperature p1 Intake vacuum p2 Intermediate circuit pressure p3 final pressure

Claims

[1] comprising a system for diagnosing and monitoring air supply systems: a compressor (1) configured to provide compressed air, and an air dryer configured to remove moisture from the compressed air in the system, characterized by , that the system further exhibits: at least two sensors (2), wherein one sensor (2) is configured and arranged to detect a status signal of a component to be monitored, and another sensor (2) is configured and arranged to detect a reference signal with respect to the component to be monitored, an evaluation unit (3) configured to evaluate the signals of the sensors (2) by comparing the status signal and the reference signal, wherein the evaluation unit (3) is further configured to convert the sensor signals into maintenance and / or control signals using an evaluation logic, which control the operating mode of the air supply system, and wherein the sensors (2) are configured and arranged to determine the temperature at the cooling air inlet as a reference signal and a component temperature or an oil temperature as a status signal, and / or the temperature of the air at the process inlet as a reference signal and the component temperature or the oil temperature as a status signal, and / or the intake pressure as a reference signal and the intermediate pressure or the final pressure as a status signal, and / or the air temperature as a reference signal and the pressure dew point as a status signal based on the measured values ​​of humidity and the temperature of the air in the compressor. [2] System according to claim 1, wherein at least one of the sensors (2) is configured and arranged such that, depending on the type of compressor (1), it detects the cooling air temperature, the intake temperature, the cylinder wall temperature, the oil temperature, the outlet temperature, the final pressure and / or the intake vacuum for monitoring the condition and controlling the compressor (1). [3] System according to one of the preceding claims, wherein the system comprises a data transmission unit (4) configured to transmit evaluated or unevaluated information from a vehicle to a roadside device for data processing (14). [4] System according to the preceding claim, wherein the system comprises a vehicle-side evaluation unit (3) and a road-side device for data processing (14) configured to perform the evaluation of the sensor signals in multiple stages. [5] System according to one of the two preceding claims, wherein the pathside device for data processing (14) is part of the system and comprises at least one database and / or a web server (7). [6] System according to any one of the preceding claims 3 to 5, wherein the system is configured such that data transmission between the vehicle and the roadside device for data processing (14) is carried out using WLAN and / or mobile communications. [7] System according to the preceding claim 5, wherein the pathside device for data processing is configured to collect data from different diagnostic systems of different vehicles and has an output unit (9) configured to output the data from different vehicles together. [8] System according to one of the preceding claims, wherein a CAN bus network or an Ethernet is provided and the sensors (2) and the evaluation unit (3) are arranged in the CAN bus network or the Ethernet and the evaluation unit (3) in the CAN bus network is configured to act as a bus master, wherein the sensors (2) have signal converters configured to convert the signals in such a way that they are suitable for transmission in the corresponding network. [9] System according to any of the preceding claims, wherein the system comprises a signal converter configured to convert the sensor signals for transmission to the evaluation unit (3). [10] System according to one of the preceding claims, wherein the vehicle-side evaluation unit (3) is implemented in a central brake control unit.

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