Patent Publication Number: US-2017363030-A1

Title: Method of identifying a faulted component in an automotive system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Great Britain Patent Application No. 1610617.1, filed Jun. 17, 2016 which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure pertains to a method of identifying a faulted component in an automotive system. 
     BACKGROUND 
     Automotive systems include several interconnected devices such as an internal combustion engine, a turbocharged system, an Exhaust Gas Recirculation (EGR) system, an aftertreatment system and several other components such as conduits, valves, sensors, fuel injectors and so on. 
     Due to the complexity of current automotive systems, it is not always easy and straightforward to determine the particular component that is not functioning properly, in case of a fault. 
     Some faults may be determined by receiving data from the sensors of the automotive system and comparing such data with predefined thresholds or ranges and reporting a fault code if the measured data do not comply with such predefined thresholds or ranges. Nevertheless, a variety of faults may not be easily detected using on-board sensors. 
     Furthermore, currently a high number of No Trouble Found (NTF) events are caused by replacement of good components in service because robust tools to understand the cause of the automotive system noise are not available. For example, it happens frequently that turbochargers are substituted in case of a certain noise is produced when, in reality, the failed part is a scissor gear associated to a camshaft. 
     In general, current service procedures are based on the experience of the service personnel but may not always effective. 
     Accordingly, there is a need to provide a method to detect and distinguish between different faulted components such as engine, turbocharger, balancer wheels, injectors and so on. 
     SUMMARY 
     An embodiment of the disclosure provides a method of identifying a faulted component in an automotive system including an internal combustion engine managed by an Electronic Control Unit, the method includes operating the internal combustion engine according to a predefined detection routine. A noise signal emitted by the activated internal combustion engine is recorded in a data carrier or storage medium. The recorded noise signal is analyzed by a signal treatment algorithm to determine a plurality of vibration modes of the automotive system from the noise signal. The amplitude of the noise signal at each vibration mode is compared with an acceptable amplitude threshold. A faulted component of the automotive system is identified when the amplitude of the correspondent vibration mode is greater than the acceptable amplitude threshold. 
     It is noted that with “detection routine” a predefined operating mode of the internal combustion engine is meant. Typically, a detection routine is defined by predetermined values of one or more engine operating parameters (e.g. engine speed) in a predetermined time interval. In other words, the engine is operated in a predetermined manner for a predetermined time interval. 
     An advantage of this embodiment is that it allows to reduce the number of No Trouble Found (NTF) events. Another advantage is that it allows to improve customer satisfaction when diagnosing and repairing a vehicle. 
     According to another embodiment, the predefined internal combustion engine detection routine includes ramping up an engine speed for a predefined amount of time. An advantage of this embodiment is that it allows the automotive system to vibrate at frequencies that span from a minimum frequency to a maximum frequency to identify a wide number of vibration modes. 
     According to another embodiment, the predefined internal combustion engine detection routine includes ramping up the engine speed from 1000 rpm to 4000 rpm in 120 seconds. An advantage of this embodiment is to adapt the detection routine to internal combustion engines. 
     According to a further embodiment, the signal treatment algorithm is a Fast Fourier Transform (FFT). An advantage of this embodiment is that it converts the noise signal from its original time domain to a representation in the frequency domain. 
     According to still another embodiment, each vibration mode is compared with a correspondent pre-determined acceptable amplitude threshold. 
     According to a further embodiment, an acoustic sensor or microphone is used to record the noise signal emitted by the automotive system. An advantage of this embodiment is that it allows the use of a microphone generally present in the infotainment system of the vehicle or of an external microphone. 
     The present disclosure further includes an apparatus for the identification of a faulted component in an automotive system including an internal combustion engine managed by an Electronic Control Unit. The apparatus is configured to operate the internal combustion engine according to a predefined detection routine; record a noise signal emitted by the activated internal combustion engine in a data carrier or storage medium; analyze the recorded noise signal according to a signal treatment algorithm in order to determine a plurality of vibration modes of the automotive system from the noise signal; compare the amplitude of the noise signal at each vibration mode with an acceptable amplitude threshold; and identify a faulted component of the automotive system if the amplitude of the correspondent vibration mode is greater than the acceptable amplitude threshold. 
     The advantages of this embodiment are substantially the same as those described in reference to the method. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements. 
         FIG. 1  shows an automotive system; 
         FIG. 2  is a cross-section of an internal combustion engine belonging to the automotive system of  FIG. 1 ; 
         FIG. 3  shows an apparatus for carrying out the method of the various embodiments of the present disclosure; and 
         FIG. 4  shows a block diagram of an embodiment of the method herein disclosed. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description. 
     Some embodiments may include a turbocharged automotive system  100 , as shown in  FIGS. 1 and 2 , that includes an internal combustion engine (ICE)  110  having an engine block  120  defining at least one cylinder  125  having a piston  140  coupled to rotate a crankshaft  145 . A cylinder head  130  cooperates with the piston  140  to define a combustion chamber  150 . A fuel and air mixture (not shown) is disposed in the combustion chamber  150  and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston  140 . The fuel is provided by at least one fuel injector  160  and the air through at least one intake port  210 . The fuel is provided at high pressure to the fuel injector  160  from a fuel rail  170  in fluid communication with a high-pressure fuel pump  180  that increases the pressure of the fuel received from a fuel source  190 . Each of the cylinders  125  has at least two valves  215 , actuated by a camshaft  135  rotating in time with the crankshaft  145 . The valves  215  selectively allow air into the combustion chamber  150  from the port  210  and alternately allow exhaust gases to exit through a port  220 . In some examples, a cam phaser  155  may selectively vary the timing between the camshaft  135  and the crankshaft  145 . 
     The air may be distributed to the air intake port(s)  210  through an intake manifold  200 . An air intake duct  205  may provide air from the ambient environment to the intake manifold  200 . In other embodiments, a throttle body  330  may be provided to regulate the flow of air into the manifold  200 . In still other embodiments, a forced air system such as a turbocharger  230 , having a compressor  240  rotationally coupled to a turbine  250 , may be provided. Rotation of the compressor  240  increases the pressure and temperature of the air in the duct  205  and manifold  200 . An intercooler  260  disposed in the duct  205  may reduce the temperature of the air. The turbine  250  rotates by receiving exhaust gases from an exhaust manifold  225  that directs exhaust gases from the exhaust ports  220  and through a series of vanes prior to expansion through the turbine  250 . The exhaust gases exit the turbine  250  and are directed into an aftertreatment system  600 . This example shows a variable geometry turbine (VGT) with a VGT actuator  290  arranged to move the vanes to alter the flow of the exhaust gases through the turbine  250 . In other embodiments, the turbocharger  230  may be fixed geometry and/or include a waste gate. 
     The aftertreatment system may include an exhaust line  275  having one or more exhaust aftertreatment devices. The aftertreatment devices may be any device configured to change the composition of the exhaust gases. Some examples of aftertreatment devices include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NO x  traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters, such as a Diesel Particulate Filter (DPF). 
     In particular, the aftertreatment system may include a Diesel Oxidation Catalyst (DOC)  285  upstream of a SCRF (Selective Catalytic Reduction SCR on Filter)  280 . 
     In alternative with respect to the SCRF  280 , a lean NO x  trap LNT (not represented for simplicity) may be provided in the aftertreatment system. 
     Other embodiments may include an exhaust gas recirculation (EGR) system  300  coupled between the exhaust manifold  225  and the intake manifold  200 . The EGR system  300  may include an EGR cooler  310  to reduce the temperature of the exhaust gases in the EGR system  300 . An EGR valve  320  regulates a flow of exhaust gases in the EGR system  300 . 
     The automotive system  100  may further include an electronic control unit (ECU)  450  in communication with one or more sensors and/or devices associated with the ICE  110 . The ECU  450  may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE  110 . The sensors include, but are not limited to, an air mass-flow and temperature sensor  340 , a manifold pressure and temperature sensor  350 , a combustion pressure sensor  360 , coolant and oil temperature and level sensors  380 , a fuel rail pressure sensor  400 , a cam position sensor  410 , a crank position sensor  420 , exhaust pressure and temperature sensors  430 , an EGR temperature sensor  440 , and an accelerator pedal position sensor  445 . Furthermore, the ECU  450  may generate output signals to various control devices that are arranged to control the operation of the ICE  110 , including, but not limited to, the fuel injectors  160 , the throttle body  330 , the EGR Valve  320 , the VGT actuator  290 , and a cam phaser. Note, dashed lines are used to indicate communication between the ECU  450  and the various sensors and devices, but some are omitted for clarity. 
     Turning now to the ECU  450 , this apparatus may include a digital central processing unit (CPU) in communication with a memory system, or data carrier  460 , and an interface bus. The CPU is configured to execute instructions stored as a program in the memory system, and send and receive signals to/from the interface bus. The memory system may include various storage types including optical storage, magnetic storage, solid state storage, and other non-volatile memory. The interface bus may be configured to send, receive, and modulate analog and/or digital signals to/from the various sensors and control devices. The program may embody the methods disclosed herein, allowing the CPU to carry out the steps of such methods and control the ICE  110 . 
     The program stored in the memory system is transmitted from outside via a cable or in a wireless fashion. Outside the automotive system  100  it is normally visible as a computer program product, which is also called computer readable medium or machine readable medium in the art, and which should be understood to be a computer program code residing on a carrier, the carrier being transitory or non-transitory in nature with the consequence that the computer program product can be regarded to be transitory or non-transitory in nature. 
     An example of a transitory computer program product is a signal, e.g. an electromagnetic signal such as an optical signal, which is a transitory carrier for the computer program code. Carrying such computer program code can be achieved by modulating the signal by a conventional modulation technique such as QPSK for digital data, such that binary data representing the computer program code is impressed on the transitory electromagnetic signal. Such signals are e.g. made use of when transmitting computer program code in a wireless fashion via a Wi-Fi connection to a laptop. 
     In case of a non-transitory computer program product the computer program code is embodied in a tangible storage medium. The storage medium is then the non-transitory carrier mentioned above, such that the computer program code is permanently or non-permanently stored in a retrievable way in or on this storage medium. The storage medium can be of conventional type known in computer technology such as a flash memory, an Asic, a CD or the like. 
     Instead of an ECU  450 , the automotive system  100  may have a different type of processor to provide the electronic logic, e.g. an embedded controller, an on-board computer, or any processing module that might be deployed in the vehicle. 
     The automotive system may further include an apparatus  600  for the identification of faulted components  700 , as depicted in  FIG. 3 . 
     The apparatus  600  includes a visual interface  610  associated with a software  620 . For example, the software  620  may be embedded in the infotainment of the vehicle as a human to machine interface (HMI). 
     The apparatus  600  may also include an acoustic sensor  630  configured to acquire a noise signal  640  produced by the operations of the automotive system  100 , for example a microphone. The acoustic sensor  630  may be internal or external with respect to a vehicle  105  powered by the automotive system  100 . 
     The software  620  may be used to enable the activation of the internal combustion engine  110  according to a predefined detection routine  680 . The recorded noise signal  640  of the automotive system  100  may be stored in the recording data carrier  460  associated to the ECU  450 . Furthermore, a pre-determined acceptable signal amplitude threshold  670  may also be stored in the recording data carrier  460  associated to the ECU  450 . 
       FIG. 4  shows a block diagram of an embodiment of the method herein disclosed. The method of identification of a faulted component starts with the activation of the software  620  of the apparatus  600  by the visual interface  610 . The activation may be performed by service personnel (Block  800 ). 
     The software is programmed in such a way that, once activated, it enables the activation of the internal combustion engine  110  according to the predefined detection routine. Furthermore, the acoustic sensor  630  is activated. The acoustic sensor  630  records the noise signal  640  emitted by the automotive system  100  as activated with the predefined detection routine. 
     In a preferred embodiment of the present disclosure the acoustic sensor  630  may be a microphone and the predefined detection routine  680  may consists in ramping up the engine speed from 1000 rpm to 4000 rpm in 120 seconds (Block  810 ). Other detection routines are possible. 
     The noise signal  640  produced by the activated automotive system  100  may be stored in the data carrier  460  (Block  820 ) and is analyzed by the ECU  450  according to a signal treatment algorithm  650  to determine a plurality of vibration modes  660 . In a preferred embodiment of the present disclosure the signal treatment algorithm  650  may be a Fast Fourier Transform (FFT) that enables to translate the time domain noise signal  640  emitted by the automotive system  100  in a frequency domain signal to determine the vibration modes  660  (Block  830 ). 
     Before analyzing the noise signal  640  emitted by the automotive system  100  with the signal treatment algorithm  650 , filtrating operations may be performed to purify the noise signal emitted by the automotive system  100  from the environment noise. 
     As stated above, a pre-determined acceptable amplitude threshold  670  may be also stored in the data carrier  460 . 
     The signal treatment algorithm  650  not only recognizes in the noise emitted by the automotive system  100  as a plurality of vibration modes  660 , but is also able to compare each vibration mode with the pre-determined acceptable amplitude threshold  670  to identify a faulted component  700  of the automotive system  100  if the correspondent vibration mode is greater than the acceptable amplitude threshold  670  (Block  840 ). The comparison between the noise signal emitted by the automotive system  100  and the acceptable amplitude threshold  670  is performed in the frequency domain. 
     As can be clearly seen in the spectrum reported in Block  840 , every vibration mode coming from the FFT of the noise signal emitted by the automotive system  100  is compared with the pre-determined acceptable amplitude threshold  670 . Whenever the amplitude of a particular vibration mode exceeds the amplitude of the threshold  670 , the software  620  indicates the component related to that particular vibration mode as faulted. 
     On the contrary, when the amplitude of a particular vibration mode is lower than the amplitude of threshold  670  the software  620  indicates the component related to that particular vibration mode as not faulted. 
     It is to be noted that each vibration mode coming from the FFT can be related to a specific component of the combustion engine  110  or to a specific fault of a component of the automotive system  100 . In such a way, each vibration mode enables the unique recognition of the faulted component  700 . 
     Once the diagnostic method is completed, an array showing components status of the combustion engine  110  is displayed on the visual interface  610  (Block  850 ). 
     In another embodiment of the present disclosure the visual interface  610  and the related software  620  may be embedded as an application in an electronic mobile module, so as to enable the user of the vehicle to perform the method above described without the necessity of specialized personnel. According to this embodiment of the present disclosure the software may be downloaded on the electronic mobile module as a dedicated application. 
     In still another embodiment of the present disclosure the acceptable amplitude threshold  670  may be determined by the ECU  450  once the FFT is performed and the noise signal emitted by the automotive system  100  is translated into the frequency domain. In particular, the amplitude threshold  670  may be determined averaging the vibration modes in the neighborhood of the vibration mode of interest. 
     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.