Systems and procedures for diagnosing auxiliary equipment associated with an engine

Abstract

Method for an auxiliary equipment (130, 140) electrically coupled to a generator (120) functionally connected to a piston engine (110), comprising: measuring a DC link parameter (172) associated with the generator (120) during operation using a DC link sensor (171); and diagnosing a condition of the auxiliary equipment (130, 140) based on a frequency content (420) of the DC link parameter (171) using at least one processor (152).

Description

AREA OF INVENTION

[0001] The embodiments of the subject matter described herein relate to systems and methods for diagnosing an engine and associated auxiliary equipment. GENERAL STATE OF THE ART

[0002] Engine components and associated auxiliary equipment can wear differently during operation. For example, an engine cylinder may misfire due to a worn spark plug. A radiator fan (auxiliary equipment) may begin to wobble due to an unbalanced fan blade. The performance of a traction motor (auxiliary equipment) may be impaired due to a break in a motor coil winding.

[0003] A known approach to detecting engine wear is, for example, disclosed in US Patent 2006 / 0047408A1. This patent describes diagnostic analysis devices for evaluating the functionality of an internal combustion engine. More precisely, information about the engine's functionality is provided by analyzing and displaying the output voltage of an electric generator driven by the engine. The output signals of the engine-driven generator are analyzed at various times. In addition to evaluating the generator signals, specific engine functions can be analyzed by evaluating other signals, such as those from sensors for ignition spark or injection signals. The key feature here lies in the specific networking of the electronic devices and the signal processing formulas used.

[0004] US 2009 / 0 139 781 A1 generally relates to electric vehicles, which usually have a battery as an energy storage device to power and move the vehicle. According to one disclosed embodiment, a vehicle has a battery, an electric motor, control circuits for controlling the energy flow, two heat exchange circuits for temperature control in the occupant area and the battery, and a charger with which the battery is charged via an external voltage source.

[0005] Furthermore, US patent 2004 / 0148926A1 discloses a system for detecting anomalies in the secondary air supply of an internal combustion engine, which is necessary for activating a catalyst in the exhaust system. The disclosed system also enables precise calculation of the secondary air quantity without the use of additional sensors and independent of the air-fuel ratio. The system detects anomalies to protect the catalyst from thermal deterioration. In this way, the operation of the vehicle can be ensured even in the event of a malfunction.

[0006] Another approach to detecting engine or accessory wear is engine speed monitoring. Diagnostic routines can monitor whether engine speed components exceed a threshold and generate diagnostic codes or other indicators that may require maintenance, engine power reduction, engine shutdown, accessory power reduction, or accessory shutdown.

[0007] The inventors of this device recognized, however, that analyzing engine speed is often insufficient to thoroughly diagnose an engine or auxiliary equipment problem. Furthermore, engine speed is often independent of certain types of auxiliary equipment (e.g., generator-driven auxiliary equipment) connected to the engine, such as a radiator fan or a traction motor. SUMMARY

[0008] In one embodiment according to the present invention, a method for auxiliary equipment electrically coupled to a generator functionally connected to a piston engine is disclosed. The method includes measuring a DC link parameter associated with the generator during operation using a DC link sensor and diagnosing a condition of the auxiliary equipment based on the frequency content of the DC link parameter using at least one processor.

[0009] In a further embodiment of the invention, a method for auxiliary equipment functionally connected to a rotating shaft of a piston engine is disclosed. The method includes measuring the rotational speed of the piston engine's rotating shaft during operation and diagnosing a condition of the auxiliary equipment based on the frequency content of the shaft speed.

[0010] In one embodiment of the invention, a vehicle system is disclosed. The vehicle system comprises a generator, auxiliary equipment electrically coupled to the generator, a DC link sensor for measuring a DC link parameter associated with the generator during operation, and a control unit. The control unit includes instructions configured for sampling and transforming the measured DC link parameter, identifying the frequency content of the DC link parameter, and diagnosing a condition of the auxiliary equipment based on the frequency content of the DC link parameter.

[0011] Furthermore, in one embodiment according to the present invention, a vehicle system is disclosed. The vehicle system comprises a piston engine with a rotating shaft, auxiliary equipment functionally coupled to the rotating shaft, a sensor for measuring the rotational speed of the rotating shaft over time during operation, and a control unit. The control unit includes instructions configured for scanning and transforming the measured rotational speed, identifying the frequency content of the rotational speed, and diagnosing a condition of the auxiliary equipment based on the frequency content of the rotational speed.

[0012] In one embodiment, a test set is disclosed. The test set includes a control unit that is functional for determining a condition of an auxiliary equipment electrically coupled to a generator over time, based on the frequency content of a measured DC link parameter associated with the generator.

[0013] In one embodiment, a test set is disclosed. The test set includes a control unit that is functionally capable of determining a condition of an accessory equipment functionally coupled to a rotating shaft of a piston engine, based on the frequency content of a measured rotational speed of the shaft over time.

[0014] This summary is provided to introduce, in simplified form, a selection of concepts that are further described herein. It is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to embodiments that resolve any or all of the disadvantages mentioned in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will be better understood by reading the following description of non-limiting embodiments with reference to the attached drawings, wherein below: Fig. 1. An illustration of an exemplary embodiment of a vehicle system (e.g., a locomotive system) comprising a motor and a generator (alternator), shown herein as a rail vehicle configured for operation on a track over a plurality of wheels. Fig. 2 an illustration of an exemplary embodiment of the motor and generator of Fig. 1 is, which are functionally connected with various additional equipment 140 and traction motors, Fig. 3. An illustration of exemplary embodiments of this is how a frequency content is generated using a time-sampled DC link parameter. Fig. 4 is an illustration showing exemplary embodiments of “healthy” and “unhealthy” frequency content, Fig. 5. An illustration of an exemplary embodiment of this is how diagnostic logic in the control unit can detect an unhealthy condition in the frequency content of a DC link parameter. Fig. 6. An illustration of an exemplary embodiment of this is how wear is limited to a specific auxiliary system, and Fig. 7 An illustration of an exemplary embodiment of this is how a diagnosis of an additional equipment condition is carried out using a series of matched bandpass filters. DETAILED DESCRIPTION

[0016] Embodiments of the invention disclosed herein relate to systems and methods for diagnosing auxiliary equipment belonging to an engine. Test sets for carrying out the methods are also provided. The engine may be integrated into a vehicle, such as a locomotive system. Other suitable vehicle types may include road vehicles, all-terrain vehicles, mining machines, aircraft, and watercraft. Other embodiments of the invention may also be used for stationary engines such as wind turbines or generators. The engine may be a diesel engine or it may burn another fuel or fuel combination. Such alternative fuels may include gasoline, kerosene, biodiesel, natural gas, and ethanol, as well as combinations of the foregoing. Suitable engines may use compression ignition and / or spark ignition.These vehicles may contain an engine with components that wear out during use.

[0017] Furthermore, embodiments of the subject matter disclosed herein use generator data such as measured electrical generator parameters or generator data (e.g., a derived torque profile) derived from measured electrical generator parameters and / or motor parameters (e.g., speed) to determine auxiliary equipment conditions and to differentiate between conditions and associated motor components and auxiliary equipment.

[0018] When searching for specific types of engine wear, an engine can be placed in a special operating condition, state, or mode. For example, engine diagnostics can be performed under a dead-load condition as part of a test procedure, a dynamic braking (db) setting condition, or a steady-state operating condition. Similarly, when searching for specific types of auxiliary equipment wear, an auxiliary system can be placed in a special operating condition, state, or mode. The diagnostic and predictive procedures discussed herein can be used for trend analysis, comparing cylinder variations, performing tests, confirming repairs, and assisting with repairs. Alternatively, generator and / or engine data can be sampled and analyzed when the engine reaches a specific operating condition or state during normal operation.

[0019] Fig. Figure 1 illustrates an exemplary embodiment of a vehicle system 100 (e.g., a locomotive system), depicted herein as a rail vehicle 106 configured for operation on a track 102 via a plurality of wheels 108. As shown, the rail vehicle 106 includes a motor 110 functionally connected to a generator (alternator) 120. The rail vehicle 106 also includes traction motors 130 functionally connected to the generator 120 for driving the wheels 108. Furthermore, the vehicle 106 includes various components functionally connected to the generator 120 or the motor 110 (e.g., the rotating motor shaft 111, see Figure 1). Fig. 2) connected auxiliary systems or devices 140 for performing various functions. The traction motors 130 are in Fig. Although marked separately, they are considered here as a type of additional equipment.

[0020] The vehicle 106 further includes a control unit 150 for controlling various components related to the vehicle system 100. In one example, the control unit 150 includes a computer control system. In one embodiment, the computer control system is largely software-based and includes a processor such as the processor 152, configured to execute computer-usable instructions. The control unit 150 can include multiple engine control units (ECUs), and the control system can be distributed across each of the ECUs. The control unit 150 further includes computer-readable storage media such as the memory 154, including instructions (e.g., computer-executable instructions) for enabling onboard monitoring and control of the rail vehicle operation. The memory 154 can include volatile and non-volatile memory.According to another embodiment, the control unit can be hardware-based and use, for example, digital signal processors (DSPs) or other hardware logic circuits to perform the various functions described herein.

[0021] The control unit can manage and control the vehicle system 100. The control unit can receive a signal from a motor speed sensor 160 or from various generator sensors 170 to determine operating parameters and conditions, and adjust various motor actuators 162 accordingly to control the operation of the rail vehicle 106. In one embodiment, the speed sensor includes a multi-toothed sensor wheel connected to the motor shaft 111 and a reluctance sensor that detects when a tooth of the sensor wheel passes the reluctance sensor. For example, the control unit can receive signals representing various generator parameters from different generator sensors. Generator parameters may include DC link voltage, DC link current, generator field voltage, generator field current, generator output voltage, and generator output current.Other generator parameters may also be possible according to various embodiments. Accordingly, the control unit can control the vehicle system by sending commands to various components such as traction motors, alternator, cylinder valves, throttle valve, etc. Signals from generator sensors 170 can be bundled together in one or more wiring harnesses to reduce the space in the vehicle system 100 that is devoted to wiring and protecting the signal lines from abrasion and vibration.

[0022] The control unit can include electronic on-board diagnostics for recording characteristic operating characteristics of the engine. These characteristic operating characteristics can include, for example, measurements from sensors 160 and 170. In one embodiment, the characteristic operating characteristics can be stored in a database memory 154. In another embodiment, current characteristic operating characteristics can be compared with past characteristic operating characteristics to determine performance trends of the engine and / or the auxiliary equipment.

[0023] The control unit can include electronic on-board diagnostics for identifying and recording potential wear and potential faults of components of the vehicle system 100. For example, if a potentially worn component is identified, a diagnostic code can be stored in memory 154. In one embodiment, a unique diagnostic code can correspond to each type of wear that may be identified by the control unit. For example, a first diagnostic code can indicate a problem with cylinder 1 of the engine, a second diagnostic code can indicate a problem with cylinder 2 of the engine, a third diagnostic code can indicate a problem with one of the auxiliary systems, and so on.

[0024] The control unit can also be linked to the display 180, such as a diagnostic interface display, which provides a user interface for locomotive operators and maintenance personnel. The control unit can control the engine in response to operator input via operator input controls 182 by sending a command to adjust various engine actuators 162 accordingly. Non-limiting examples of user input controls 182 include a throttle control, a brake control, a keypad, and a circuit breaker. Furthermore, characteristic operating features of the engine and auxiliary equipment, such as diagnostic codes corresponding to worn components, can be reported to the operator and / or maintenance personnel via the display 180.

[0025] The vehicle system can include a communication system 190 that is linked to the control unit. In one embodiment, the communication system 190 can include a radio and an antenna for sending and receiving voice and data messages. For example, data transmissions can take place between the vehicle system and a railway control center, another locomotive, a satellite, and / or a trackside device such as a switch. For example, the control unit can estimate the vehicle system's geographic coordinates using data from a GPS receiver. As another example, the control unit can transmit characteristic operating properties of the engine and / or auxiliary equipment to the control center via a message transmitted by the communication system 190.In one embodiment, a message can be transmitted from the communication system 190 to the command center when a worn component of the engine or auxiliary equipment is detected, and the maintenance of the vehicle system can be planned.

[0026] Fig. Figure 2 is an illustration of an exemplary embodiment of the motor 110 and the generator 120 of Fig. 1, which are functionally connected with various additional equipment 140 ( 141, 142, 143, 144) and traction motors 130.

[0027] Various mechanical auxiliary equipment 144 can be functionally coupled to and driven by the rotating motor shaft 111. Other auxiliary equipment 140 is driven by the generator 120 via a rectifier 210, which generates a DC link voltage for operating controllers 230. Examples of such auxiliary equipment include a blower 141, a compressor 142, and a cooling fan 143. The traction motors 130 are driven by the generator 120 via the rectifier, which generates the DC link voltage for a frequency converter 220. Such auxiliary equipment 140, traction motors 130, and their configurations are well known in the art. According to certain embodiments, the generator 120 can even be one or more generators, such as a main generator for driving the traction motors 130 and an auxiliary generator for driving part of the auxiliary equipment 140.Other examples of additional equipment include turbochargers, pumps, engine cooling systems, brake resistors and energy storage systems.

[0028] The speed sensor 160 measures the rotational speed of the motor's rotating shaft 111 during operation. The DC link sensor 171 is a generator sensor and, depending on the embodiment, can measure DC link voltage, DC link current, or both. The field sensor 172 is a generator sensor and, depending on the embodiment, can measure the generator's field current, generator's field voltage, or both. According to certain embodiments, generator sensors 173 and 174 are provided for measuring the generator's armature output voltage and current, respectively. Suitable commercially available sensors can be selected based on application-specific parameters.

[0029] The AC output of generator 120, referring again to Fig. 2, is rectified by the rectifier 210 to form a DC link voltage, which is applied via a DC bus to various auxiliary systems or equipment. The DC link voltage controls some auxiliary equipment (e.g., blower 141, compressor 142, and cooling fan 143) via power controller 230. The DC link voltage drives the traction motors 130 via a frequency converter 220.

[0030] According to one embodiment, the DC link voltage is measured by the DC link sensor 171 and analyzed by the control unit 150 to determine a condition of the auxiliary equipment based on the frequency content of the DC link voltage. A Fourier transform process 310 or a bandpass filter process 320 can be used to determine the frequency content of the DC link voltage, as shown in Fig. Figure 3 shows that for auxiliary systems operating discontinuously, time-frequency analysis methods such as short-time Fourier transform or wavelet transform can be used. Alternatively, the DC link current can be measured and used instead of the DC link voltage. The control unit 150 is configured to analyze one or more components of the frequency content, narrow it down to a specific auxiliary system, and determine the condition of that specific auxiliary system (e.g., down to a specific component of the auxiliary system). According to one embodiment, the motor 110 can first be driven to a specified operating condition, state, or mode before the diagnostics are performed on the auxiliary equipment.

[0031] The control unit 150 samples the DC link parameter over time and performs a frequency analysis process on the DC link parameter data. According to one embodiment, the frequency analysis is a Fourier transform process 310 (e.g., a Fast Fourier Transform (FFT) process). According to another embodiment, the frequency analysis process is a bandpass filter process 320. The frequency analysis process transforms the DC link parameter of the sampled time domain into frequency content in the frequency domain. The various frequency components of the frequency content can include DC link frequency components (zero order), fundamental frequency components (first order), and harmonic frequency components (second order, half order, third order, etc.). The fundamental frequencies for each of the connected auxiliary systems could be different, depending on the speed / operating mode of the auxiliary systems.According to one embodiment, the Fourier transform process and the bandpass filter process include computer-executable instructions that are executed by processor 152. The frequency transformation can be performed on processed / derived signals such as kilovolt-amperes (kVA) or kilowatts (kW), which are the product of current and voltage, or on the torque, which is kW / frequency of the signal.

[0032] The engine can have multiple cylinders that fire in a predetermined sequence, with each cylinder firing once during a four-stroke or two-stroke cycle. For example, a four-cylinder, four-stroke engine might have a firing order of 1-3-4-2, with each cylinder firing once every two engine revolutions. The firing frequency of each cylinder is therefore half the engine's rotational frequency, and the firing frequency of each cylinder is twice the engine's rotational frequency. The engine's rotational frequency can be described as the first engine order. Such a first-order frequency component can be seen in the frequency content of the measured generator parameter. The firing frequency of each cylinder in a four-stroke engine can be described as half the engine order, where half the engine order is half the engine's rotational frequency.Such a half-order frequency component can also be seen in the frequency content of the measured DC link parameter. Similarly, various auxiliary systems (fans, pumps, compressors, traction motors, etc.) can have cyclic components that also generate frequency components appearing in the DC link parameter.

[0033] A twelve-cylinder engine, as another example of a four-stroke engine, can have a firing order of 1-7-5-11-3-9-6-12-2-8-4-10, with each cylinder firing once every two engine revolutions. The firing frequency of any given cylinder is therefore half the engine's revolution frequency, and the firing frequency of any cylinder is six times the engine's revolution frequency. As an example of a two-stroke engine, a twelve-cylinder engine can have a firing order of 1-7-5-11-3-9-6-12-2-8-4-10, with each cylinder firing once per engine revolution. The firing frequency of any given cylinder is therefore the engine's revolution frequency, and the firing frequency of any cylinder is twelve times the engine's revolution frequency. These frequency components can also be seen in the frequency content of the measured DC link parameter.

[0034] For example, the motor could be a four-stroke engine running at 1050 rpm. The first motor order is therefore 17.5 Hz, and half the motor order is 8.75 Hz. The DC link voltage can vary with a periodic frequency as the motor shaft 111 rotates during operation. For example, the frequency content of the DC link voltage can include a frequency component at the first motor order frequency. That is, the peak of the frequency content can occur at the first-order frequency component. The DC link voltage can also include frequency content at other harmonics of the first order, such as a second-order frequency (twice the motor frequency), a third-order frequency (three times the motor frequency), and so on.Similarly, the DC link voltage can contain frequency content at frequencies smaller than the first-order frequency, such as the half-order frequency (half the motor frequency).

[0035] For a motor or auxiliary system that is "healthy" and functioning correctly, the frequency content of the measured DC link parameter may have a specific healthy signature. Deviations from such a healthy signature may indicate a problem with the motor or auxiliary system. For example, according to one embodiment, a condition of an auxiliary system can be determined by analyzing a half-order magnitude and / or phase of the frequency content.

[0036] Fig. Figure 4 is an illustration showing exemplary embodiments of “healthy” and “unhealthy” frequency content. According to one embodiment, the frequency content 410 of the healthy auxiliary system (i.e., an auxiliary system that functions correctly) has three frequency components of absolute and relative magnitudes, as shown in Fig. Figure 4 shows that the frequency content 420 of the unhealthy motor (i.e., an auxiliary system that is not functioning properly due to wear or a fault) has three frequency components in the same positions as in the frequency content 410 for the healthy motor. According to one embodiment, however, the amplitude of one frequency component 421 (e.g., a half-order component) is distorted (e.g., amplitude increased), and the amplitude of another frequency component 423 (e.g., a second-order component) is also distorted (e.g., amplitude attenuated). The distorted frequency components 421 and 423 in the frequency content 420 indicate an unhealthy auxiliary system. Furthermore, the respective characteristic properties of the distorted frequency components (e.g., amplitude) relative to the other frequency components in the frequency content 420 of the unhealthy auxiliary system can reveal a specific type of wear or failure.The half-order component phase can also be used with respect to a reference component of the additional system to narrow down a problem to a specific component of the additional system.

[0037] Worn components can lead to less efficient operation of the auxiliary system. Furthermore, the condition of worn components can accelerate their wear, increasing the likelihood of total auxiliary system failure and operational breakdowns. The diagnostic system can include both a wear warning and an indication of the type and / or location of the worn auxiliary system component.

[0038] Fig. Figure 5 illustrates an embodiment of how a diagnostic logic 510 in the control unit 150 can detect an abnormal condition in the frequency content of a DC link parameter. For example, the diagnostic logic 510 can compare the half-order component 421 with a threshold level T. If the magnitude of component 421 exceeds the threshold level T, the diagnostic logic 510 determines that wear has occurred in an auxiliary system. Furthermore, if the diagnostic logic 510 determines that the ratio of the half-order component to the first-order component 422 exceeds a second threshold level, and the ratio of the first-order component to the second-order component 423 exceeds a third threshold level, the diagnostic logic 510 isolates the wear to a specific auxiliary system component.According to one embodiment, the diagnostic logic includes computer-executable instructions that are executed by processor 152. According to another embodiment, the ratio of a half-order component to a DS component or zero-order component can indicate an accessory equipment problem. Furthermore, the threshold level T can depend on an operating condition of the accessory equipment, such as power, speed, environmental conditions, repair history, etc.

[0039] Examples of auxiliary system wear or failure types that can be identified, differentiated, and narrowed down include an unbalanced radiator fan, a defective compressor, or a worn traction motor. Once wear or a fault has been detected, appropriate action can be taken. Such actions may include, for example, providing a warning signal to the driver (e.g., via indicator 180), adjusting an auxiliary system operating parameter (e.g., reducing the auxiliary system's power, deactivating part of the auxiliary system, or deactivating all auxiliary equipment), logging a maintenance action, and transmitting the detected condition to a central location (e.g., via communication system 190).

[0040] Fig. Figure 6 illustrates an exemplary embodiment of how wear is localized to a specific auxiliary system. A specific frequency component of the frequency content from the FFT process or the bandpass filter process is tracked (in frequency) by a phase-locked loop (PLL) process 610 of the control unit 150. A frequency component can move due to a change in an operating condition (e.g., compressor speed, radiator fan speed, engine speed, etc.). According to one embodiment, the operating condition, state, or mode (e.g., speed) of a specific auxiliary system (e.g., the radiator fan 143) can be varied by the control unit 150. If the specific component varies according to the varying operating condition, state, or mode of the specific auxiliary system (as tracked by the PLL process), then this specific frequency component is correlated with this specific auxiliary system.The amplitude and / or phase of the tracked frequency component from the PLL process can be compared with one or more threshold values ​​to identify the specific problem (e.g., a particular worn component) within the confined auxiliary system.

[0041] According to one embodiment, a multitude of frequency components of the DC link voltage (or DC link current) are continuously monitored and correlated with the specific auxiliary equipment. If a specific frequency component does not correlate with a specific auxiliary system, then a condition, state, or operating condition of the motor 110 (e.g., speed) can be varied to determine whether the specific frequency component correlates with the motor. In this way, motor wear and auxiliary equipment wear can be distinguished. According to one embodiment, the various auxiliary systems provide feedback to the control unit 150 (via sensor indicators) so that the control unit knows which condition is being varied by which auxiliary system.

[0042] Consequently, if a specific frequency component suddenly appears in the frequency content of the DC link voltage, the methods described herein can be further used to narrow down the frequency component to the motor or the auxiliary equipment. If the motor is ruled out, the methods described herein can then be used to further narrow down the problem to a specific auxiliary system and ultimately to a specific problem in that specific auxiliary system. For example, a 12 Hz frequency component that suddenly appears in the frequency content of the DC link voltage can be ruled out as originating from the motor by varying the motor speed. Operating states of the radiator fan 143, the compressor 142, the blower 141, and the traction motor 130 are varied successively by the control unit 150 until finally the 12 Hz component is traced back to the traction motor 130.The amplitude of the 12 Hz component is then compared with several threshold values, and it is determined that a total failure of train motor 130 is likely to occur soon. Consequently, train motor 30 is switched off.

[0043] Various mechanically driven auxiliary equipment 144, again referring to Fig. 2. The accessories referred to in Section 2 can be functionally coupled to the rotating shaft 111 of the motor 110. Examples of such mechanically driven equipment include pumps and motor cooling systems. According to one embodiment, the rotational speed of the motor 110's rotating shaft is measured (via the speed sensor 160), and the control unit 150 determines a condition for the accessories based on the frequency content of the shaft speed.

[0044] A Fourier transform process 310 or a bandpass filter process 320 can again be used to determine the frequency content of the shaft rotation. For auxiliary systems that operate discontinuously, time-frequency analysis methods such as short-time Fourier transform or wavelet transform can be used. The control unit 150 is configured to analyze one or more components of the frequency content, narrow down the analysis to a specific auxiliary system coupled to the rotating shaft 111, and determine the condition of the specific auxiliary system (e.g., down to a specific component of the auxiliary system). According to one embodiment, the motor 110 or one of the auxiliary devices can first be driven to a specified operating condition, state, or mode before the diagnostics are performed on the auxiliary device.For example, if during diagnostics a frequency generated by the engine is the same as, or very similar to, a frequency generated by the auxiliary equipment, then the operating mode / frequency of the engine, the auxiliary equipment, or both can be changed to achieve frequency separation. This separation can be performed during the diagnostic process.

[0045] Again Fig. Figure 6 illustrates an exemplary embodiment of how wear is localized to a specific auxiliary system. A specific frequency component of the frequency content from the FFT process or the bandpass filter process is tracked (in frequency) by a phase-locked loop (PLL) process 610 of the control unit 150. According to one embodiment, the operating condition, state, or mode (e.g., rotational speed) of a specific auxiliary system (e.g., a pump) can be varied by the control unit 150. If the specific frequency component varies according to the varying operating condition, state, or mode of the specific auxiliary system (as tracked by the PLL process), then this specific frequency component is correlated with this specific auxiliary system.The amplitude and / or phase of the tracked frequency component can be compared with one or more threshold values ​​to identify the specific problem in the isolated auxiliary system.

[0046] According to one embodiment, a multitude of frequency components of the shaft speed frequency content are continuously monitored and correlated with the specific auxiliary equipment coupled to the shaft 111. According to another embodiment, the various auxiliary systems provide feedback to the control unit 150, so that the control unit knows which condition is being varied by which auxiliary system. Consequently, if a specific frequency component suddenly appears in the frequency content of the speed signal, the methods described herein can be used to isolate the frequency component to the auxiliary equipment and ultimately to a specific problem in that particular auxiliary system.

[0047] According to one embodiment, the control unit 150 is functional to report a worn condition of an accessory, e.g., via the display 180 and the communication system 190. Furthermore, according to one embodiment, the control unit 150 includes instructions configured to set an accessory operating parameter (e.g., fan speed) based on the detected condition.

[0048] One embodiment includes a test set comprising a control unit that is functionally capable of determining the condition of electrically coupled auxiliary equipment connected to a generator based on the frequency content of a measured DC link parameter associated with the generator over time. The test set may further include a sensor for detecting the DC link parameter associated with the generator (e.g., voltage or current). The control unit is also functionally capable of exchanging data with the sensor to sample the DC link parameter over time and to extract its frequency content.

[0049] Another embodiment includes a test set with a control unit that is functionally capable of determining a condition of auxiliary equipment coupled to a rotating shaft of a piston engine, based on the frequency content of a measured shaft rotational speed over time. The test set may further include a sensor for detecting the shaft rotational speed. The test set is also functionally capable of exchanging data with the rotational speed sensor for sampling the rotational speed over time and extracting the frequency content of the rotational speed.

[0050] Alternatively, instead of using a PLL process, the DC link voltage (or DC link current) or the speed signal can be processed by a series of bandpass filters in the control unit 150, each tuned to a specific frequency corresponding to operation under particular conditions. Square mean values ​​(QMW) of the filtered signals (or another combination, e.g., average, of the filtered signals) provide an indication of the health of the auxiliary components (e.g., by comparing the QMW with determined threshold values). Fig. Figure 7 illustrates an exemplary embodiment of how an additional equipment condition is carried out using a series of matched bandpass filters 710 together with a QMW process 720 provided by the control unit (e.g. in the form of computer-executable instructions) and a comparator process 730.

[0051] Instead of using a PLL process, the DC link voltage or the speed signal can again be processed by the FFT process or the bandpass filter process, and patterns in the frequency content can be analyzed by the control unit to identify fault types or wear of the auxiliary equipment. Since the operating fundamental frequency of the specific auxiliary system is known in advance, various harmonics in the frequency content can be correlated with specific auxiliary equipment. For example, a subharmonic frequency of 12 Hz can be correlated with an auxiliary system operating at a fundamental frequency of 24 Hz.

[0052] Both the frequency content of the speed signal and the frequency content of the DC link voltage (or DC link current) can be used to determine the condition of the auxiliary equipment. The various methods described herein can be used in specific ways, using the speed and DC link signals, to differentiate from the engine, to narrow down the problem to a specific auxiliary system, and further to narrow down the problem to a specific component of the auxiliary system.

[0053] The following are further examples of the embodiments of systems and methods described herein. These examples illustrate various approaches for diagnosing and differentiating between various types of auxiliary system wear based on the frequency content of DC link data and / or engine speed data.

[0054] In one embodiment, a worn-out auxiliary system can be detected based on a frequency content signature, such as the fact that the magnitude of the half-order frequency component is greater than a half-order threshold. In another embodiment, the frequency content magnitudes can be integrated over the frequency range, and a worn-out component of an auxiliary system can be detected based on the fact that the integration is greater than a significant threshold.

[0055] Detecting a worn component when other components of the auxiliary system are healthy (or less worn) can result in a more distinct frequency content signature than when multiple components of the auxiliary system are worn. For example, the frequency content signature of a worn component can be identified by comparing the magnitude of its half-order frequency component to a half-order threshold. However, multiple worn components may have a different frequency component signature than a single worn component. Furthermore, the position of multiple worn components in the operational sequence can alter their frequency content signature.For example, two worn components that are 180° out of phase may have a different frequency component signature than two worn components that wore consecutively in the operating sequence, and the methods disclosed herein can therefore identify one or more worn components based on various changes in the frequency content signature. Furthermore, it may be advantageous to generate a frequency content signature of a healthy auxiliary system by recording the frequency content at different frequencies and operating conditions. In one embodiment, the frequency content of an auxiliary system can be compared with the frequency content signature of a healthy auxiliary system. Anomalies that do not match the frequency content signature of the healthy auxiliary system or of any other worn auxiliary system component can, for example, be identified and reported by the control unit.

[0056] In one embodiment, the time-domain DC link data can be filtered by a low-pass filter with a cutoff frequency slightly higher than the first-order frequency. For example, the cutoff frequency can be ten or twenty percent higher than the first-order frequency. In one embodiment, the cutoff frequency can therefore be determined by the motor speed. The DC link data can be sampled at a frequency equal to or greater than the Nyquist rate. In one embodiment, the time-domain signal can be sampled at a frequency greater than twice the first-order motor frequency (or the first-order auxiliary system frequency). In another embodiment, the time-domain signal can be sampled at a frequency greater than twice the frequency of the motor's red line.By using low-pass filters and sampling at a frequency equal to or greater than the Nyquist rate, the frequency component of the DC link data cannot be distorted by aliasing. The same applies to motor speed data.

[0057] As discussed herein, the sampled DC link data (e.g., DC link voltage, DC link current) and / or motor speed data can be transformed to generate frequency-domain frequency content. In one embodiment, a Fast Fourier Transform can be used to generate the frequency-domain frequency content. In another embodiment, a correlation algorithm can be applied to compare the frequency content of the DC link data and / or motor speed data with a signature for an auxiliary system condition. For example, the signature for a healthy auxiliary system might include frequency content at the first-order frequency with a magnitude below a first-order threshold and frequency content at the half-order frequency with a magnitude below a half-order threshold. The first-order threshold might correspond to an operating state of the auxiliary system.

[0058] For example, historical auxiliary system data can be stored in a database containing samples of the frequency content from the auxiliary system's previous operation. This allows for the detection of trends in the frequency content, which can then be used to determine the auxiliary system's health. For instance, an increasing half-order component value for a given cooling fan speed and load might indicate that a cooling fan is wearing out.

[0059] In one embodiment, the frequency content of the DC link data and / or engine speed data can be stored in a database containing historical auxiliary equipment data. For example, the database can be stored in memory 154 of the control unit 150. Alternatively, the database can be stored at a location remote from the rail vehicle 106. For example, historical data can be encapsulated in a message and transmitted via the communication system 190. In this way, a control center can monitor the health of the auxiliary equipment in real time. For example, the control center can perform steps to determine the condition of the auxiliary equipment using the DC link data and / or engine speed data transmitted via the communication system 190.For example, the command center can receive DC link voltage data from the rail vehicle 106, frequency-transform the DC link voltage data, apply a correlation algorithm to the transformed data, and detect potential wear in an auxiliary system. Furthermore, the command center can schedule maintenance work and deploy healthy locomotives and maintenance personnel to optimize the system's components. Historical data can also be used to assess the health of auxiliary equipment before and after equipment inspections, modifications, and component replacements.

[0060] In one embodiment, a potential fault can be reported to the locomotive operating personnel via display 180. Once notified, the driver can stop operating the rail vehicle 106 to reduce the potential for further wear of the auxiliary equipment. In another embodiment, a message indicating a potential fault can be transmitted to a command center via communication system 190. Furthermore, the severity of the potential fault can be reported. For example, diagnosing a fault based on the frequency content of DC link data and / or engine speed data can enable earlier detection of a fault than if the fault is determined using only average auxiliary system information. Therefore, the auxiliary system can potentially continue operating if a potential fault is detected in the early stages of wear.Conversely, it may be desirable to shut down the auxiliary system or schedule immediate maintenance if a potential fault is determined to be severe. In one embodiment, the severity of a potential fault can be determined according to the difference between a threshold value and the magnitude of one or more components of the frequency content of the DC link and / or speed data.

[0061] Analyzing the frequency content of DC link data and / or motor speed data may allow for monitoring and diagnosis of auxiliary equipment during operation. Furthermore, the operation of an auxiliary system with a worn component can be discontinued to potentially reduce further wear of the component and thus the likelihood of additional auxiliary system failures during operation. For example, a half-order component can be compared to a half-order threshold. In one embodiment, the potential disturbance can be a first worn component if the magnitude of the half-order component is greater than the half-order threshold. However, if the magnitude of the half-order component is not greater than the half-order threshold, the potential disturbance can be a second worn component.

[0062] In one embodiment, the potential fault can be reported to the locomotive operating personnel via display 180, and the driver can stop operation of the rail vehicle 106 to reduce the potential for further wear. In another embodiment, a message diagnosing the potential fault can be transmitted to the command center via communication system 190.

[0063] In one example, the half-order frequency component of the DC link and / or speed data can be monitored for each deactivated component of an auxiliary system. The component may be worn out if the half-order frequency component falls below a half-order threshold while the component is deactivated.

[0064] The component can be considered healthy if the half-order frequency component remains above the half-order threshold while the component is deactivated. That is, the worn component may be the one contributing a larger amount of frequency content to the half-order frequency component than other auxiliary system components. In one embodiment, the selective deactivation diagnosis can be performed when the auxiliary system is operating at idle or under light partial load.

[0065] It may be more desirable to shut down an auxiliary system than to allow a worn component to fail in a way that could cause further damage to the auxiliary system. In one embodiment, a threshold can be determined to indicate that continued operation of the auxiliary system might be undesirable because the potential disturbance is severe. For example, the potential disturbance can be judged to be severe if a half-order quantity of the frequency component exceeds a threshold. The auxiliary system can be shut down if the severity of the potential disturbance exceeds the threshold.

[0066] A request to schedule an inspection can be sent, for example, via a message transmitted through communication system 190. Furthermore, the downtime of the rail vehicle 106 can be reduced by transmitting the potential fault condition and its severity. For example, the inspection of a rail vehicle 106 can be postponed if the potential fault has a low severity level. The downtime can be further reduced by reducing the auxiliary system's power, such as by adjusting an auxiliary system operating parameter based on the detected condition. It can be determined whether the auxiliary system's power reduction is activated. For example, reducing the auxiliary system's power can decrease the magnitude of one or more components of the frequency content of the DC link data.

[0067] In one embodiment, a test set can be used to identify the frequency content of the DC link data and / or engine speed data and to diagnose a condition of the auxiliary equipment based on the frequency content of the data. For example, a test set can include a control unit that is functionally capable of communicating with one or more DC link sensors and / or engine speed sensors and that is functionally capable of sampling the associated data. The control unit can further be functionally capable of transforming signals from the one or more sensors into a frequency content that represents frequency information of the auxiliary equipment. The control unit can further be functionally capable of diagnosing a condition of the auxiliary equipment based on the frequency content of the generator data from the sensors. The test set can further include one or more sensors for acquiring DC link parameters (e.g.,GS intermediate circuit voltage) and / or motor parameters (e.g. motor speed).

[0068] The patent description and claims refer to a number of terms which have the following meanings. The singular forms "a," "an," and "the" include the plural unless the context clearly indicates otherwise. To modify a quantitative representation that could permissibly vary without altering the fundamental function to which it relates, approximate language, such as that used throughout the description and claims herein, may be employed. Accordingly, a value modified by a term or terms such as "about" is not to be limited to the exact value stated. In some cases, the approximate language may correspond to the accuracy of an instrument used to measure the value.Similarly, "free" can be used in conjunction with a term and may include an insignificant number or traces of it while still being considered free from the modified term. Furthermore, unless otherwise stated, the use of the terms "first," "second," etc., does not denote any order or degree of importance, but rather the terms "first," "second," etc., are used to distinguish elements from one another.

[0069] As used herein, the terms “can” and “may” indicate a possibility of occurrence within a circumstantial clause, the possession of a specific quality, characteristic, or function, and / or qualify another verb by expressing one or more of an ability, capacity, or possibility associated with the qualifying verb. Accordingly, the use of “can” or “may” indicates a modified term that appears appropriate, capable, or suitable for an indicated capacity, function, or use, while acknowledging that the modified term may sometimes not be appropriate, capable, or suitable in certain circumstances.For example, in some circumstances an event or capacity may be expected, while in other circumstances the event or capacity may not occur—this distinction is captured by the terms "may" and "might be." The terms "generator" and "alternator" are used interchangeably herein (though it is acknowledged that, depending on the application, one or the other may be more appropriate). The terms "frequency content" and "harmonic content" are used interchangeably and may refer to fundamental frequency (and / or phase) components and associated harmonic frequency (and / or phase) components above and below the fundamental components. The term "instructions," as used herein in relation to the control unit or processor, may refer to computer-executable instructions.

[0070] The embodiments described herein are examples of articles, systems, and methods that have elements corresponding to those of the invention as defined in the claims. This written description will enable a person skilled in the art to manufacture and use embodiments with alternative elements that are equally equivalent to those defined in the claims. The scope of the invention therefore includes articles, systems, and methods that do not deviate from the literal language of the claims and also includes other articles, systems, and methods with insignificant differences from the literal language of the claims. Although only certain features and embodiments are illustrated and described herein, a person skilled in the art may conceive of many modifications and changes. The appended claims cover all such modifications and changes. Reference symbol list

[0071] 100 Vehicle system 102 Track 106 Rail vehicle 108 Wheels 110 Engine 111 Engine shaft 120 Generator (alternator) 130 Traction motor(s) 140 Auxiliary systems 141 Blower 142 Compressor 143 Radiator fan 144 Mechanically driven auxiliary equipment 150 Control unit 152 Processor 154 Memory 160 Speed ​​sensor 162 Motor actuators 170 Generator sensor(s) 171 DC link sensor 172 Field sensor 173 Generator output voltage sensor 174 Generator output current sensor 180 Display 182 User input controls 190 Communication system 210 Rectifier 220 Frequency converter 230 Power controller 310 FFT process 320 Bandpass filter process 410 Frequency content of a healthy auxiliary system 420 Frequency content of a worn auxiliary system 421 Frequency component 422 Frequency component 423 Frequency component 510 Diagnostic logic 610 PLL process 710 Series of tuned bandpass filters 720 QMW process 730 Comparator process

Claims

[1] A method for an accessory equipment (130, 140) electrically coupled to a generator (120) operatively connected to a reciprocating engine (110), comprising: measuring a DC link (172) parameter associated with the generator (120) during operation with a DC link sensor (171); and diagnosing a condition of the accessory equipment (130, 140) based on a frequency content (420) of the DC link (171) parameter using at least one processor (152). [2] The method of claim 1, wherein the DC link (171) parameter is a DC link (171) voltage. [3] The method of claim 1, wherein the DC link (171) parameter is a DC link (171) current. [4] The method of claim 1, further comprising tracking at least one component of the frequency content (420) as an operating condition, state, or mode of the reciprocating engine (110) and / or the auxiliary equipment (130, 140) varies. [5] The method of claim 4, further comprising correlating the tracked frequency component with the varied piston engine (110) or the varied auxiliary equipment (130, 140). [6] A method for an accessory equipment (130, 140) operatively coupled to a rotating shaft (111) of a reciprocating engine (110), comprising: measuring the rotational speed of a rotating shaft (111) of the reciprocating engine (10) during operation and diagnosing a condition of the accessory equipment (130, 140) based on frequency content (420) of the rotational speed of the shaft (111). [7] The method of claim 6, further comprising tracking at least one component of the frequency content (420) as an operating condition, state, or mode of the reciprocating engine (110) and / or the auxiliary equipment (130, 140) varies. [8] The method of claim 7, further comprising correlating the tracked frequency component with the varied piston engine (110) or the varied auxiliary equipment (130, 140). [9] A vehicle system (100) comprising: a generator (120), auxiliary equipment (130, 140) electrically coupled to the generator (120), a DC link sensor (171) for measuring a DC link (171) parameter associated with the generator (120) during operation, and a controller (150) including instructions configured to: sample and transform the measured DC link (171) parameter, identify the frequency content (420) of the DC link (171) parameter, and diagnose a condition of the auxiliary equipment (130, 140) based on the frequency content (420) of the DC link (171) parameter. [10] The vehicle system (100) of claim 9, wherein the DC link (171) parameter is a DC link (171) voltage. [11] The vehicle system (100) of claim 9, wherein the DC link (171) parameter is a DC link (171) current. [12] The vehicle system (100) of claim 9, wherein the control unit (150) is functional for reporting a worn condition of an accessory equipment (130, 140). [13] A vehicle system (100) comprising: a piston engine (110) having a rotating shaft (111), auxiliary equipment (130, 140) electrically coupled to the rotating shaft (111), a sensor (160) for measuring a rotational speed of the rotating shaft (111) over time during operation and a control unit (150) including instructions configured to: sample and transform the measured speed, identify the frequency content (420) of the speed, and diagnose a condition of the auxiliary equipment (130, 140) based on the frequency content (420) of the speed. [14] The vehicle system (100) of claim 13, wherein the control unit (150) is functional for reporting a worn condition of an accessory equipment (130, 140).

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