SYSTEM AND METHOD FOR MONITORING AN ENGINE

BACKGROUND

[0001] Embodiments of the present disclosure generally relate to monitoring a vehicle and more specifically to monitoring an engine of the vehicle.
[0002] During the course of operation an engine may experience one or more faults. In one example, the faults experienced by the engine may be categorized as mechanical faults and operational faults. Some examples of mechanical faults experienced by the engine may include a degraded crank case, a degraded turbocharger, a degraded cylinder, a worn out ignition plug, and the like. Also, the operational faults of the engine typically include faults that occur due to variations in operational quantities of the engine, such as a fuel-gas ratio, quantity of fuel available, an atomization of fuel, a timing of firing, and the like. The operational faults may also include a misfire in an engine cylinder, an engine cylinder imbalance, and the like.

[0003] Typically, a misfire in the engine cylinder and/or the engine cylinder imbalance results in a sub-optimal performance of the vehicle. In particular, the engine misfire affects fuel economy, emissions, and idle quality of the vehicle. Also, a misfiring engine cylinder may result in exhaust from the vehicle that may have unusually high levels of hydrocarbons. Compliance with emission standards across different geographies calls for the level of hydrocarbons in the exhaust to be maintained within predefined limits. Hence, timely identification of an engine fault and subsequent control of operational quantities of the engine is essential. However, effective detection of engine faults and control of operational quantities of the engine are challenging tasks.

[0004] In general, some presently available techniques detect the operational faults in the engine via use of knock sensors, speed sensors, pressure sensors, temperature sensors, and the like. Use of these sensors for detecting the engine faults increases the cost and complexity of monitoring the engine. By way of example, temperature sensors are generally slow in responding. Delayed response of the temperature sensors impedes real time detection of the engine operational faults. The delayed detection of the engine operational faults may in turn delay corrective action to rectify the operational faults in the engine.

[0005] In recent times, engine faults have been also detected based on electrical parameters of the vehicle. However, use of the electrical parameters typically facilitates the detection of any mechanical faults in the engine. Although some techniques provide real time detection of faults, any corrective action based on this detection is provided in an offline fashion. Furthermore, the corrective action may call for certain components of the engine to be shut down, deactivated, or operated at a reduced capacity thereby causing the engine to operate at a de-rated power.

BRIEF DESCRIPTION

[0006] In accordance with aspects of the present disclosure, a method for monitoring an engine disposed in a machine is presented. The method includes acquiring a parameter corresponding to one or more components of the machine. Further, the method includes determining a signature corresponding to the acquired parameter. Moreover, the method includes analyzing the determined signature corresponding to the acquired parameter to identify an operational fault in the machine. In addition, the method includes regulating in real time at least one operational quantity corresponding to the machine based on the identified operational fault.

[0007] In accordance with another aspect of the present disclosure, a system for monitoring an engine disposed in a machine is presented. The system includes a measurement device operatively coupled to one or more components of the machine. Further, the system includes a controller operatively coupled to the one or more components of the machine. The controller is configured to acquire a parameter corresponding to the one or more components of the machine. Further, the controller is configured to determine a signature of the parameter corresponding to the one or more components of the machine. Moreover, the controller is configured to analyze the determined signature of the at least one of the parameter corresponding to the one or more components of the machine to identify an operational fault in the machine. Additionally, the controller is configured to regulate in real time at least one operational quantity corresponding to the machine based on the identified operational fault.

DRAWINGS

[0008] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0009] FIG. 1 is a diagrammatical representation of a system for monitoring a machine, according to aspects of the present disclosure;

[0010] FIG. 2 is a flow chart representing an exemplary method for monitoring a machine, according to aspects of the present disclosure; and

[0011] FIG. 3 is a diagrammatical representation of a signature of a DC link voltage representing an operational fault in a machine, according to aspects of the present disclosure.

DETAILED DESCRIPTION

[0012] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terms "first", "second", and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Also, the terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. The term "or" is meant to be inclusive and mean one, some, or all of the listed items. The use of "including," "comprising" or "having" and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "connected" and "coupled" are not restricted to physical or mechanical connections or couplings, and can include electrical connections or couplings, whether direct or indirect. Furthermore, terms "circuit" and "circuitry" and "controller" may include either a single component or a plurality of components, which are either active and/or passive and are connected or otherwise coupled together to provide the described function. Also, the term operatively coupled as used herein includes wired coupling, wireless coupling, electrical coupling, magnetic coupling, radio communication, software based communication, or combinations thereof.

[0013] As will be described in detail hereinafter, various embodiments of an exemplary system and method for monitoring an engine disposed in a machine are presented. Specifically, a system and method for monitoring an engine of a vehicle are presented. Employing the system and method for monitoring the condition of the engine of the vehicle described hereinafter, allows real time regulation of an operational quantity of an engine of the vehicle.

[0014] Turning now to the drawings and by way of example in FIG. 1, a diagrammatical representation of a system 100 for monitoring a machine, according to aspects of the present disclosure is depicted. In one non-limiting example, the machine may include the engine. Moreover, in another example, the engine may be operatively coupled to the machine. Furthermore, in one example, the machine may be a vehicle 101. The vehicle 101 may be a locomotive, a truck, a car, a bus, and the like.

[0015] Further, the vehicle 101 may include an engine 102 operatively coupled to a generator 104 and a combination of a rectifier and a DC link 106. In one example, the generator 104 may include an electrical alternator, a synchronousgenerator, a synchronous singly fed generator, an induction singly fed generator, a doubly fed generator, a brushless wound-rotor doubly fed generator, a magneto hydrodynamic generator, and the like.

[0016] In one embodiment, the engine 102 may include a dual fuel engine. As will be appreciated, the dual fuel engine may employ a gas and fuel mixture. The dual fuel engine may include a mixture of diesel and natural gas, in one example. Moreover, in another example, the engine 102 may be a diesel engine, a reciprocating engine, a gasoline based engine, and the like. Also, the engine 102 may include one or more cylinders 103, a crankshaft, one or more pistons, a crankcase, or combinations thereof. It may be noted that the crankcase forms housing for the crankshaft. In one example, the engine 102 may include twelve cylinders. Moreover, the twelve cylinders may be mounted in the crankcase in two banks of six cylinders each. Furthermore, twelve pistons corresponding to the twelve cylinders may drive a common crankshaft.

[0017] Also, in one example, the engine 102 may include a four stroke engine, a two stroke engine, and the like. As will be appreciated, the four strokes of the engine 102 may include intake, compression, power, and exhaust strokes. Moreover, the four strokes of the engine 102 may be completed in two separate revolutions of the crankshaft. By way of example, a twelve cylinder engine may be configured to complete the four strokes in two separate revolutions of the crankshaft. In addition, for a twelve cylinder engine, each of the twelve cylinders may fire once during the two separate revolutions of the engine's crankshaft. The two separate revolutions of the engine's crankshaft may correspond to one engine cycle. Accordingly, each of the twelve cylinders may fire once in one engine cycle. In one example, when a rotational speed of the engine crankshaft is 1000 rpm, a rotational frequency of the engine may be 16.67 Hz. Accordingly, a time period of one revolution of the engine's crankshaft may be about 60 ms and a time period of one engine cycle may be about 120 ms. Therefore, in a twelve cylinder engine, each of the twelve cylinders may fire once in about 120 ms. It

may be noted that the time period of one engine cycle may vary with the variation in the rotational speed of the engine crankshaft.

[0018] Further, it may be noted that one revolution of engine's crankshaft corresponds to an angular displacement of 360 degrees. Therefore, one engine cycle may correspond to an angular displacement of 720 degrees. However, in a two stroke engine one engine cycle may correspond to an angular displacement of 360 degrees. In the twelve cylinder engine, each of the twelve cylinders may operate at an angular phase shift with respect to the remaining cylinders.

[0019] In addition, the vehicle 101 may include an inverter 108 operatively coupled to a motor 110. Moreover, the system 100 may include a measurement device 112 and a controller 114. In one non-limiting example, the controller 114 may form a part of the vehicle 101. The measurement device 112 may be configured to measure parameters corresponding to the engine 102, the generator 104, and the DC link 106, in one example. Also, the controller 114 may be configured to acquire the parameters measured by the measurement device 112. The term 'parameter' as used herein may be used to refer to an electrical parameter, a mechanical parameter, or a combination thereof.

[0020] In accordance with aspects of the present disclosure, the acquired parameters corresponding to the engine 102 may include an engine crank angle, an engine speed, a geometrical dimension, or combinations thereof. In one non-limiting example, the geometrical dimensions of the engine 102 may include a weight of a piston of the engine 102, a length of the piston of the engine 102, a diameter of the piston of the engine 102, and the like. The acquired parameter corresponding to the generator 104 may include a mechanical parameter and/or an electrical parameter. Similarly, the acquired parameter corresponding to the DC link 106 may include an electrical parameter. In one example, the electrical parameter corresponding to the generator 104 and the DC link 106 may include a voltage, a current, or a combination thereof. Also, the mechanical parameter corresponding to the generator 104 may include a rotational speed.

[0021] Furthermore, the controller 114 may be configured to estimate a derived parameter based on the acquired parameters corresponding to the engine 102, the generator 104, and the DC link 106. In one non-limiting example, the derived parameter may include an electromagnetic torque corresponding to the generator 104, an inertial torque corresponding to the engine 102, a crankshaft torsional mode corresponding to the engine 102, an engine torque or combinations thereof. In another example, the derived parameter may include an electromagnetic power corresponding to the generator 104.

[0022] In addition, a signature of at least one of the derived parameter and the acquired parameter may be determined. In particular, signatures corresponding to one or more of the electrical parameter corresponding to the generator 104, the electrical parameter corresponding to the DC link 106, the electromagnetic torque of the generator 104, the engine torque, or combinations thereof may be determined. These signatures may be analyzed to identify any operational faults corresponding to the vehicle 101. Particularly, the signatures may be analyzed to identify operational faults corresponding to the engine 102. In one example, the operation faults of the engine 102 may include a misfire in an engine cylinder, an engine cylinder imbalance, and the like. The operational faults may arise in the engine 102 due to variations in operational quantities, such as a fuel-gas ratio, an injection quantity, an atomization of fuel, an injection timing, and the like. In one non-limiting example, the operational fault corresponding to the engine 102 may be identified in at least one engine cycle. By way of example, the operational fault in the engine 102 may be identified in about 120 ms. Furthermore, in one example, mechanical faults experienced by the engine 102 may include a degraded crank case, a degraded turbocharger, a degraded cylinder, a worn out ignition plug, and the like.

[0023] Moreover, the controller 114 may be configured to employ a signal processing technique to analyze the signatures corresponding to the derived parameter and/or the acquired parameter. The signal processing technique may include a Fast Fourier Transform (FFT), a Discrete Fourier Transform (DFT), a time domain analysis, a wavelet analysis, a band pass filtering, or combinations thereof. Other signal processing techniques may also be employed for analyzing the signatures corresponding to the derived parameter and/or acquired parameter. In one non-limiting example, the FFT and DFT corresponding to the derived parameter and/or the acquired parameter may have a magnitude and a phase of the derived parameter and/or the acquired parameter with respect to the engine crank angle. Furthermore, in one example, the signature of only the acquired parameter may be analyzed to identify operational faults in the engine 102. Additionally, in another example, the signature of only the derived parameter may be analyzed. Furthermore, in yet another example, the signature of a combination of the acquired and derived parameters may be analyzed.

[0024] Furthermore, the controller 114 may be configured to compare the signatures of at least one of the derived parameter and the acquired parameter with a threshold value. Specifically, the controller 114 may be configured to compare the spectral energy of the signature of at least one of the derived parameter and the acquired parameter in a band of frequencies with the threshold value to identify an operational fault in the engine 102. The threshold value may include a baseline value corresponding to a condition of the one or more components of the vehicle 101. In particular, in one example, the threshold value may include a baseline value corresponding to a condition of the engine 102 of the vehicle 101. In one example, the condition of the engine 102 may include a healthy condition, a condition corresponding to a given operational fault, and the like. Moreover, in one non-limiting example, the healthy condition of the engine 102 of the vehicle 101 may include a condition when the engine 102 is devoid of any operational faults and mechanical faults. In another example, the threshold value may be determined based on a field trial, an experimental simulation, and the like. The analysis of the determined signature of the derived parameter and/or the acquired parameter will be explained in greater detail with respect to FIG. 3.

[0025] In addition, the controller 114 may be configured to regulate in real time at least one operational quantity corresponding to the vehicle 101. More particularly, the controller 114 may be configured to regulate in real time at least one operational quantity corresponding to the engine 102 based on the identified operational fault of the engine 102. The operational quantity corresponding to the engine 102 may include a manifold air temperature, a gas-fuel ratio, an injection timing, an injection quantity, or combinations thereof. In one example, if the controller 114 determines that the operational fault in the engine 102 has occurred due to a variation in the operational quantity, the controller 114 may be configured to adjust the operational quantity in at least one engine cycle such that the operational fault is minimized in a subsequent engine cycle. In one example, the controller 114 may be configured to adjust the operational quantity in at least one engine cycle such that the operational fault is nullified in a subsequent engine cycle.

[0026] Nullifying and/or minimizing the operational fault in one engine cycle advantageously allows the vehicle 101 and in particular the engine 102 to operate at a desired operating condition in the subsequent engine cycles. In one example, the desired operating condition of the engine 102 may be a condition where the cylinders 103 corresponding to the engine 102 has a desired compression and the engine 102 has a desired combustion. Moreover, the controller 114 may be configured to adjust the operational quantity in a relatively short period of time. In one example, this period of time may be less than or equal to 500 ms. It may be desirable that the operational quantity may be adjusted by the controller 114 in less than four engine cycles.

[0027] Turning now to FIG. 2, a flow chart 200 representing an exemplary method for monitoring a vehicle, such as the vehicle 101 of FIG. 1, according to aspects of the present disclosure, is depicted. For ease of understanding, the method of FIG. 2 will be described with respect to the elements of FIG. 1. The method begins at step 202, where a parameter corresponding to one or more components of the vehicle 101 may be acquired. In one example, the acquired parameter may include an electrical parameter, a mechanical parameter, or a combination thereof. As noted hereinabove, the one or more components of the vehicle 101 may include the engine 102, the generator 104, and the DC link 106. Also, the engine 102 may be a dual fuel engine. In one non-limiting example, the acquired parameter corresponding to the DC link 106 may include a voltage, a current, or a combination thereof. Also, the acquired parameter corresponding to the generator 104 may include a voltage, a current, a rotational speed, or combinations thereof. Further, the acquired parameter corresponding to the engine 102 may include a rotational speed of the engine, a geometrical dimension of the engine, an engine crank angle, and the like.

[0028] Moreover, at step 204, a derived parameter may be estimated based on the acquired parameter. The derived parameter may include an electromagnetic torque corresponding to the generator 104, an inertial torque corresponding to the engine 102, a crankshaft torsional mode corresponding to the engine 102, an engine torque, or combinations thereof. In one example, at step 204, the electromagnetic torque of the generator 104 may be estimated by employing a generator model. The generator model may be also referred to as a d-q model of the generator. In one example, the generator model may be determined based on an inductance and a resistance of generator windings. Also, the electromagnetic torque of the generator 104 may be a function of the voltage, current, and rotational speed corresponding to the generator 104.

[0029] Furthermore, at step 204, the crankshaft torsional mode corresponding to the engine 102 may be estimated based on the acquired parameter of the engine 102. In one example, the crankshaft torsional mode may be estimated based on the geometrical dimension of the engine 102. Also, at step 204, the inertial torque corresponding to the engine 102 may be estimated based on the position of the crankshaft and the engine speed, in one example. The position of the crankshaft corresponding to a respective cylinder 103 of the engine 102 may be determined based on the engine crank angle. Accordingly, the inertial torque corresponding to the engine 102 may be a function of the engine crank angle and the engine speed. Additionally, in other example, at step 204, the engine torque may be estimated, based on the electromagnetic torque corresponding to the generator 104, the crankshaft torsional mode, and the inertial torque.

[0030] In addition, at step 206, a signature of at least one of the derived parameter and the acquired parameter may be determined. In one example, the signature of an acquired electrical parameter corresponding to the DC link 106 may be determined by sampling the electrical parameter corresponding to the DC link 106 at a plurality of time intervals and at a given sampling frequency. In a similar manner, the signature of the other acquired parameters and derived parameters may be determined. In one example, the other acquired parameters may include an electrical parameter corresponding to the generator 104. Additionally, the other derived parameters may include an electromagnetic torque corresponding to the generator 104, the engine torque, and the like.

[0031] Further, at step 208, the signatures of the derived parameter and/or the acquired parameter determined at step 206 may be analyzed. The signatures of the derived parameter and the acquired parameter may be processed via use of a signal processing technique. Additionally, the analysis of the signatures may include a comparison of the processed signatures with a threshold value. In one example, the processed signatures may be compared with a plurality of threshold values. The analysis of the signatures will be explained in greater detail with respect to FIG. 3.

[0032] At step 210, an operational fault corresponding to the vehicle 101 may be identified based on the analysis of step 208. Specifically, the operational fault corresponding to the vehicle 101 may be identified based on the comparison of the processed signatures with the threshold value. As previously noted, the operational fault corresponding to the vehicle 101 may include an operational fault in the engine 102 of the vehicle 101. Moreover, the operational fault in the engine 102 may occur due to a variation in operational quantities of the engine 102. In one non-limiting example, the operational fault in the engine 102 may be representative of an operational fault in at least one cylinder 103 of the engine 102.

[0033] The operational fault in the engine 102 may include the misfiring of the engine, in one example. The misfiring of the engine 102 may include misfiring of at least one cylinder of the one or more cylinders 103 of the engine 102. Accordingly, at step 210, the at least one cylinder which is misfiring may be identified. In particular, the at least one cylinder which may be identified by employing engine crank angle data corresponding to an instant at which the engine 102 misfires in combination with the signature of acquired and/or derived parameter. Moreover, when the engine 102 is a dual fuel engine, the operational fault in the engine may include a misfire in the dual fuel engine. The misfire in the dual fuel engine may occur due to a variation in operational quantities, such as, but not limited to, a gas-fuel ratio of the dual fuel engine. In the event of the operational fault of the engine 102, the steps 202-210 may be executed in about 120 ms, in one example.

[0034] Further, at step 212, at least one operational quantity corresponding to the vehicle 101 may be regulated in real time based on the identified operational fault. Particularly, at least one operational quantity corresponding to one or more engine cylinders in the engine 102 may be regulated in real time based on the identified operational fault. In one example, on identification of the operational fault in the engine 102, the operational quantities corresponding to the engine 102, such as, but not limited to, the injection timing may be regulated in real time. Specifically, once the operational fault in the engine 102 is identified, the operational quantities corresponding to one or more cylinders 103 of the engine 102 may be regulated in real time.

[0035] As will be appreciated, injection of fuel in a cylinder of the engine 102 may be executed in three stages. The three stages may include a pilot injection stage, a main injection stage, and a post injection stage. In one example, at step 212, based on the identified operational fault in the engine 102, the operational quantities, such as, injection timing and injection quantity corresponding to the one or more cylinders may be regulated in at least one of the pilot injection stage, the main injection stage, and the post injection stage. Particularly, in one non-limiting example, at step 212, the injection timing and the injection quantity corresponding to one or more cylinders of the engine 102 may be regulated based on the identified operational fault. Also, in yet another example, the manifold air temperature corresponding to all cylinders of the engine 102 may be regulated at step 212, based on the identification of the operational fault. By way of example, if a misfire is identified in a dual fuel engine and the reason for the occurrence of the misfire is due to a variation in gas-diesel fuel ratio, the ratio of gas and diesel fuel may be regulated in one or more cylinders of the dual fuel engine, at step 212.

[0036] In accordance with aspects of the present disclosure, the operational quantity may be regulated in real time in at least one engine cycle. It may be noted that it may be desirable to regulate the operational quantity in less than four engine cycles. By way of example, it may be desirable to regulate the operational quantity in a time period that is less than or equal to 500 ms. Regulating the operational quantity in real time may aid in nullifying the identified operational faults in a timely manner, thereby allowing the vehicle and in particular the engine 102 to operate at a desired operating condition in subsequent engine cycles.

[0037] In one example, when one cylinder 103 of the engine 102 which is misfiring is identified at step 210, the operational quantity corresponding to the misfiring cylinder 103 may be regulated in real time. Similarly, on identification of an operational fault in more than one cylinder of the engine 102, operational quantities corresponding to these cylinders may be regulated in real time.

[0038] Turning now to FIG. 3, a diagrammatical representation 300 of an electrical parameter corresponding to a DC link, such as the DC link 106 of FIG. 1 that aids in identifying an operational fault of a vehicle, such as the vehicle 101 of FIG. 1, according to aspects of the present disclosure, is depicted. Specifically, FIG. 3 represents an operational fault, such as a misfire of a cylinder of the engine 102 that may be reflected in the DC link voltage. The occurrence of the operational fault may be reflected in the signature of the electrical parameter with a delay of few milliseconds. By way of example, the operational fault may be reflected in the DC link voltage as a deviation in the signature of DC link voltage with a delay of few milliseconds. In the example of FIG. 3, reference numeral 302 may be representative of an amplitude of the DC link voltage, while reference numeral 304 may be representative of time in milliseconds. Also, reference numeral 306 may be representative of the signature of electrical parameter of the DC link 106. Specifically, reference numeral 306 may be representative of the DC link voltage.

[0039] Moreover, in the example of FIG. 3, reference numerals 316, 318, 320, 322 may be representative of the signatures of the electrical parameter associated with the DC link 106 corresponding to four consecutive engine cycles. Specifically, reference numeral 316 represents the signature of the electrical parameter associated with the DC link 106 corresponding to a first engine cycle. Reference numeral 318 represents the signature corresponding to a second engine cycle. Similarly, reference numeral 320 depicts the signature corresponding to a third engine cycle and reference numeral 322 represents the signature corresponding to a fourth engine cycle. Also reference numerals 308, 310, 312, 314 may be representative of a deviation due to an operational fault in an engine, such as the engine 102 of FIG. 1. Particularly, reference numerals 308, 310, 312, 314 may be representative of a deviation in the signature due to a misfire of a cylinder in the engine 102 of the vehicle 101. Also, reference numeral 308 may represents a deviation in the signature 316 corresponding to the first engine cycle and reference numeral 310 represents a deviation in the signature 318 corresponding to the second engine cycle. Moreover, reference numeral 312 may represent a deviation in the signature 320 corresponding to the third engine cycle and reference numeral 314 may represent a deviation in the signature 322 corresponding to the fourth engine cycle. In a presently contemplated configuration, the engine 102 may include twelve cylinders represented as Li through L12. In one example, the operational fault in the engine 102 may be a misfire in one cylinder, such as cylinder Ln of a dual fuel engine.

[0040] In accordance with aspects of present disclosure, the analysis of the signature 316 corresponding to the first engine cycle may aid in the identification of the misfiring cylinder Ln in the first engine cycle. Accordingly, at least one of an injection quantity, an injection timing, a gas-fuel ratio, and a manifold air temperature corresponding to one or more of the pilot injection stage, the main injection stage, and the post injection stage associated with the cylinder Ln of the engine 102 may be regulated in one engine cycle. Consequently, the misfiring of the cylinder Ln may be overcome or minimized in the second engine cycle. In particular, in one example, the misfiring of the cylinder Ln may be overcome before the cylinder Ln is fired in the second engine cycle. Accordingly, on overcoming the misfiring in the cylinder Ln, the signatures 318, 320, 322 corresponding to the second, third and fourth engine cycles may be devoid of respective deviations 310, 312, and 314. As a result, a real time identification of the misfiring cylinder Ln and timely regulation of the operational quantities corresponding to the misfiring cylinder Ln may be achieved.

[0041] Certain signal processing techniques may be employed to analyze the signature 300 of the electrical parameter of the DC link 106 to identify the operational fault in the engine 102. In one example, the signal processing technique may include a Fast Fourier Transformation, a band pass filtering technique, or a combination thereof. Further, the operational fault in the engine may be identified based on a comparison of these signatures with a threshold value. Although the example of FIG. 3 represents the signature of the electrical parameter of the DC link 106, a signature of an electrical parameter of the generator, a signature of electromagnetic torque of the generator, or a signature of an engine torque may also be analyzed to identify the operational fault in the engine.

[0042] As noted hereinabove, the engine 102 may be a four stroke engine. In one example, the engine 102 may operate at a speed of 1000 RPM. Therefore, the frequency of revolution of engine may be 16.67 Hz. This frequency may be referred to as a first order frequency. It may be noted that a frequency content of a DC link voltage may include a value of DC link voltage corresponding to a plurality of frequencies. Accordingly, there exists a value of the DC link voltage at a first order frequency. Similarly harmonics of the first order frequency may have corresponding values of DC link voltages. The harmonics of the first order frequency may include a second order frequency, a third order frequency, and the like. The second order frequency may be representative of a frequency that is twice the frequency of revolution of the engine. In a similar manner, the third order frequency may be representative of a frequency that is thrice the frequency of revolution of the engine. Also, a sub-harmonic of the first order frequency may include a half order frequency. In one example, the half order frequency may be representative of a frequency that is half the frequency of revolution of the engine.

[0043] Moreover, when the engine is a four stroke engine having twelve cylinders, each cylinder may be fired once in two revolutions of the engine crankshaft, as previously noted. Therefore, the firing frequency of a given cylinder may be once in two revolutions of the engine crankshaft. Hence, the firing frequency of the given cylinder may be half of the frequency of revolution of the engine. As noted hereinabove, the DC link voltage may have a value corresponding to the first order frequency, the half order frequency, the second order frequency, and the like. In one non-limiting example, if an operational fault such as an engine misfire occurs in any given cylinder, the misfire may be reflected as a deviation in the value of the DC link voltage at the half order frequency. In a similar manner, in case of a cylinder imbalance in any given cylinder, the imbalance may be reflected as a deviation in the value of the DC link voltage at the half order frequency. Use of other parameters such as other electrical parameters of the DC link, the electrical parameter of the generator, the electromagnetic torque of the generator, or the engine torque for the detection of engine misfire or cylinder imbalance may also be envisaged.

[0044] In one example, a first signal processing technique may be employed for analyzing of the electrical parameters of the DC link, the electrical parameter of the generator, the electromagnetic torque of the generator, or the engine torque. The first signal processing technique may include a band pass filtering technique. The band pass filtering technique may employ a band pass filter designed to filter the value of the DC link voltage at around the half order frequency. As previously noted, when the engine speed is 1000 rpm, the first order frequency may be at 16.67 Hz. Accordingly, the corresponding half order frequency may be at 8.33 Hz. Similarly, for a different speed of the engine, the half order frequency may have a different value. The band pass filter may be designed to filter a value of the DC link voltage in a band of frequencies around the half order frequency. As noted hereinabove, when a misfire or an engine cylinder imbalance occurs, it may be reflected in the component of the DC link voltage at the half order frequency. Therefore, by processing the DC link voltage via the customized band pass filter, a frequency content of the DC link voltage may be obtained. Particularly, the value of DC link voltage around the half order frequency may be identified. In one non-limiting example, when the speed of the engine is 1000 rpm, the band of frequencies around the half order frequency may be in a range from about 7 Hz to about 9.5 Hz. Further, a spectral energy in the band of frequencies around the half order frequency may be determined. This spectral energy may then be compared with a threshold value.

[0045] As previously noted, the threshold value may include a baseline value determined during a healthy condition of the engine. In another example, the threshold value may be determined based on a field trial, an experimental simulation, and the like. If it is determined that the spectral energy is greater than the threshold value, an anomaly condition in an engine may be identified. The anomaly condition in the engine may be representative of an operational fault in the engine. In one example, the operational fault in the engine may include misfiring in one or more engine cylinders due to reduced availability of fuel, misfiring of all cylinders of the engine, and the like.

[0046] Moreover, in one non-limiting example, the spectral energy corresponding to the band of frequencies around the half order frequency may be compared with a plurality of threshold values. In one example, the spectral energy corresponding to the band of frequencies around harmonics of the half order frequency may be compared with the plurality of threshold values. Also, each of the threshold values may correspond to various conditions and/or different operational faults. These conditions may include a complete misfire, reduced fuel availability, percentage of fuel burnt in a cylinder, number of cylinders misfiring, or combinations thereof. For ease of representation, the plurality of threshold values may be represented as Ti through T„, where n is a natural number. The threshold value Ti may be representative of a first predefined limit. The value of spectral energy corresponding to the band of frequencies around the half order frequency being greater than Ti may be indicative of a misfire in all cylinders of the engine. In a similar manner, the threshold value T2 may be representative of a second predefined limit. The value of spectral energy in the band of frequencies around the half order frequency being greater than T2 may be indicative of the number of cylinders misfiring. Similarly, the threshold value T3 may be representative of a third predefined limit. The value of spectral energy in the band of frequencies around the half order frequency being greater than T3 may be indicative of the percentage of fuel burnt in a cylinder. In a similar fashion, if the spectral energy corresponding to the band of frequencies being above the threshold values T4 through Tn may be representative of other specific predefined operational faults corresponding to the engine of the vehicle.

[0047] In other examples, a second signal processing technique may be employed for processing the DC link voltage to identify the operational faults. The second signal processing technique may include a Fast Fourier Transformation (FFT) based technique. The DC link voltage may be processed via the FFT based technique.

[0048] As previously noted, when one of the engine cylinders is misfiring, the misfiring may appear as a deviation in the DC link voltage in one engine cycle. An FFT of this DC link voltage may be determined for one engine cycle. However, as the DC link voltage corresponding to one engine cycle includes a small set of data, the FFT of this set may be of a poor quality. Hence, the DC link voltage data corresponding to more than one engine cycle may be determined to obtain a larger dataset of DC link voltage.

[0049] Subsequently, the dataset of the DC link voltage may be processed via the FFT technique to determine a frequency spectrum of the DC link voltage. The FFT of the larger dataset of DC link voltages has an enhanced quality. Once the FFT of the dataset of the DC link voltages is obtained, a half order frequency corresponding to a given engine crankshaft rotational speed may be identified. Consequently, the spectral energy at the half order frequency may be determined. In one non-limiting example, the spectral energy in a band of frequencies around the half order frequency may be determined. The spectral energy may then be compared with a plurality of threshold values to identify the operational fault. As previously noted, the plurality of threshold values may be employed to determine various operational faults such as a complete misfire, reduced fuel availability, percentage of fuel burnt in a cylinder, a number of cylinders misfiring, or combinations thereof. Furthermore, although the examples of FIGs. 1-3 are explained with respect to a vehicle, use of these embodiments with other machines is anticipated.

[0050] Furthermore, the foregoing examples, demonstrations, and process steps such as those that may be performed by the system may be implemented by suitable code on a processor-based system, such as a general-purpose or special-purpose computer. It should also be noted that different implementations of the present disclosure may perform some or all of the steps described herein in different orders or substantially concurrently, that is, in parallel. Furthermore, the functions may be implemented in a variety of programming languages, including but not limited to C++ or Java. Such code may be stored or adapted for storage on one or more tangible, machine readable media, such as on data repository chips, local or remote hard disks, optical disks (that is, CDs or DVDs), memory or other media, which may be accessed by a processor-based system to execute the stored code. Note that the tangible media may comprise paper or another suitable medium upon which the instructions are printed. For instance, the instructions may be electronically captured via optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in the data repository or memory.

[0051] The system and method for monitoring an engine of the vehicle described hereinabove aid in the early detection of any operational faults in the engine of the vehicle, thereby preventing catastrophic failure. Also, the system and method for monitoring employ sensing devices currently existing in the vehicle, thereby circumventing the need for any additional sensors. Since no additional sensors are required, the complexity and cost of the system is reduced. Also, since the system and method for monitoring the condition of engine are configured to employ the electrical parameters of the DC link and the generator and the derived parameters, a real time identification of the operational faults may be achieved. Also, the system and method described hereinabove aid in real time control based on the identification of the operational faults. The real time control aids in nullifying the operational fault in about 500 ms such that the vehicle and in particular the engine operates at a desired operating condition in subsequent engine cycles. Also, shutdown of the one or more components of the vehicle and in particular the engine may not be necessary.

[0052] While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof.

CLAIMS:
1. A method for monitoring an engine disposed in a machine, comprising:
acquiring a parameter corresponding to one or more components of the machine;
determining a signature corresponding to the acquired parameter;
analyzing the determined signature corresponding to the acquired parameter to identify an operational fault in the machine; and
regulating in real time at least one operational quantity corresponding to the machine based on the identified operational fault.

2. The method of claim 1, further comprising:
estimating at least one derived parameter based on the acquired parameter;
determining a signature corresponding to the derived parameter; and
analyzing the determined signature corresponding to the derived parameter to identify the operational fault in the machine.

3. The method of claim 2, wherein analyzing the signature corresponding to at least one of the acquired parameter and the derived parameter comprises using a time domain analysis, a Fast Fourier Transform, a Discrete Fourier Transform, a wavelet analysis, a band pass filtering, or combinations thereof.

4. The method of claim 2, wherein analyzing the signature corresponding to at least one of the acquired parameter and the derived parameter comprises comparing the signature of at least one of the acquired parameter and the derived parameter with a threshold value.

5. The method of claim, 4, wherein the threshold value comprises a baseline value corresponding to a condition of the one or more components of the machine.

6. The method of claim 1, wherein regulating in real time the at least one operational quantity comprises regulating the at least one operational quantity in at least one engine cycle such that the operational fault is nullified in a subsequent engine cycle.

7. The method of claim 6, wherein regulating in real time the at least one operational quantity comprises regulating the at least one operational quantity such that the machine operates at a desired operating condition in the subsequent engine cycle.

8. The method of claim 1, wherein the at least one operational quantity comprises a manifold air temperature, a gas-fuel ratio, an injection timing, an injection quantity, or combinations thereof.
9. The method of claim 1, wherein identifying the operational fault corresponding to the machine comprises identifying an operational fault in at least one cylinder of one or more engine cylinders.
10. The method of claim 9, wherein the operational fault corresponding to the machine comprises a misfire in the one or more engine cylinders, an imbalance in the one or more engine cylinders, or a combination thereof.

11. The method of claim 10, wherein regulating in real time the at least one operational quantity comprises regulating in real time one or more operational quantities corresponding to the one or more engine cylinders based on the identified operational fault.

12. The method of claim 1, wherein the regulating in real time the at least one operational quantity comprises regulating in real time the at least one operational quantity using a controller.

13. The method of claim 1, wherein the engine comprises a dual fuel engine, a diesel engine, a gasoline based engine, a reciprocating engine, or combinations thereof.

14. The method of claim 1, wherein the one or more components of the machine comprises a generator, the engine, a direct current link, or combinations thereof.

15. A system for monitoring an engine disposed in a machine, comprising:
a measurement device operatively coupled to one or more components of the machine;
a controller operatively coupled to the one or more components of the machine and configured to:
acquire a parameter corresponding to the one or more components of the machine;
determine a signature of the parameter corresponding to the one or more components of the machine;
analyze the determined signature of the at least one of the parameter corresponding to the one or more components of the machine to identify an operational fault in the machine; and
regulate in real time at least one operational quantity corresponding to the machine based on the identified operational fault.

16. The system of claim 15, wherein the controller is configured to estimate at least one derived parameter based on the parameter corresponding to the one or more components of the machine.

17. The system of claim 15, wherein the one or more components of the machine comprise a generator, the engine, a direct current link, or combinations thereof.

18. The system of claim 15, wherein the controller is configured to regulate the at least one operational quantity in at least one engine cycle such that the operational fault is nullified in a subsequent engine cycle.

19. The system of claim 18, wherein the controller is configured to regulate the at least one operational quantity such that the machine operates at a desired operating condition in the subsequent engine cycle.

20. The system of claim 15, wherein the engine comprises a dual fuel engine, a diesel engine, a gasoline based engine, a reciprocating engine, or combinations thereof.