Development of a Misfire Detection’s Technique Based on an Engine’s Torsional Model

2006 ◽  
Author(s):  
Davide Moro ◽  
Stefano Pantaleoni ◽  
Gabriele Serra
Keyword(s):  
Experimental Tests ◽  
Calibration Procedure ◽  
Angular Speed ◽  
Operating Conditions ◽  
False Alarms ◽  
Hall Effect Sensor ◽  
The Common ◽  
The Difference ◽  
New Diagnosis ◽  
Misfire Detection

The recent OBD requirements enforce the misfire’s diagnosis and the isolation of the cylinder where the missing combustion took place. Most of the common-used techniques developed are based on the engine’s angular speed, that is derived by the signal usually measured with an inductive or Hall-effect sensor already used for the engine’s control. The presence of single or multiple misfires (several misfires within the same engine’s cycle) induces torsional vibration in the powertrain, requiring specific filtering of the diagnostic signal to avoid false alarms. This paper presents some preliminary results, related to a 4 cylinder 1.2 liter engine mounted on an eddy-current brake test bench, obtained by a new diagnosis technique based on two speed sensors, placed near the toothed wheels used respectively for the engine and current brake’s control. The signals coming from the two sensors, applied to an equation derived by a torsional model of the engine powertrain, allow to evaluate an index based on the difference between engine and brake’s torque that highlights the misfire presence. It will be shown that this index does not require any particular calibration procedure. Experimental tests, in which single and multiple misfires are induced in several operating conditions, show clearly the algorithm’s robustness in misfire detection, especially in multiple misfire tests, where the misfiring cylinders are exactly detected.

Development of a Torsional Behavior Powertrain Model for Multiple Misfire Detection

2005 ◽  
Author(s):  
Fabrizio Ponti
Keyword(s):  
Torsional Vibration ◽  
Engine Speed ◽  
Experimental Tests ◽  
Detection Algorithm ◽  
Operating Conditions ◽  
False Alarms ◽  
Time Interval ◽  
Short Time Interval ◽  
Torsional Behavior ◽  
Misfire Detection

Many methodologies have been developed in the past for misfire detection purposes based on the analysis of the instantaneous engine speed. The missing combustion is usually detected thanks to the sudden engine speed decrease that takes place after a misfire event. Misfire detection and in particular cylinder isolation is anyhow still a challenging issue for engines with a high number of cylinders, for engine operating conditions at low load or high engine speed and for multiple misfire events. When a misfire event takes place in fact a torsional vibration is excited and shows up in the instantaneous engine speed waveform. If a multiple misfire occurs this torsional vibration is excited more than once in a very short time interval. The interaction among these successive vibrations can generate false alarms or misdetection, and an increased complexity when dealing with cylinder isolation. The paper presents the development of a powertrain torsional behavior model in order to identify the effects of a misfire event on the instantaneous engine speed signal. The identified waveform has then been used to filter out the torsional vibration effects in order to enlighten the missing combustions even in the case of multiple misfire events. The model response is also used to quicken the setup process for the detection algorithm employed, evaluating before running specific experimental tests on a test bench facility, the values for the threshold and the optimal setup of the procedure. The proposed algorithm is developed in this paper for an SI L4 engine; Its application to other engine configurations is possible, as it is also discussed in the paper.

Multiple Misfire: Detection and Cylinder Isolation Based on Engine Speed Measurement

2003 ◽  
Author(s):  
Nicolo` Cavina
Keyword(s):  
Engine Speed ◽  
Diagnostic Algorithm ◽  
Experimental Tests ◽  
Spark Ignition ◽  
Specific Pattern ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
False Alarms ◽  
Misfire Detection ◽  
Engine Cycle

The diagnosis of misfire events (or missing combustions) is enforced by On-Board Diagnostics regulations (such as CARB OBD II or European OBD) over the whole engine operating range, for all vehicles equipped with spark ignition engines. Such regulations define both the minimum misfire frequency that is to be detected (related to catalyst damage and/or increased hydrocarbons emissions), and the various misfire patterns that the diagnostic algorithm should be able to detect. In particular, single (no more than one missing combustion per engine cycle) and multiple (more than one misfiring cylinder within the same engine cycle) misfire patterns are to be diagnosed, and the cylinder in which the misfire took place is to be isolated only when single misfires take place (cylinder identification is still not mandatory for multiple misfires). Various single misfire detection methodologies have been successfully developed in recent years (mostly based on the engine speed signal), and this type of misfire diagnosis is still challenging for engines with a high number of cylinders, especially during operating conditions characterized by high engine speed and low load. On the other hand, the detection of multiple misfires is still difficult even for the typical four cylinder engine, since their effects on the engine speed trend have not yet been clarified. In fact, a misfire occurrence is characterized by a sudden engine speed decrease and a subsequent damped torsional vibration. In case of multiple misfires, the engine speed oscillation induced by the first misfiring cylinder may still be present when the second missing combustion takes place, and the resulting engine speed waveform may be erroneously interpreted by the diagnostic algorithm, thus resulting in the improper cylinder being identified or missed detection of a misfiring cylinder. This paper deals with the identification of a specific pattern in the instantaneous engine speed trend, induced by a missing combustion and characteristic of the system under study, that allows performing the desired multiple misfire detection. The methodology has been designed in order to be run on-board, thus requiring low computational power and memory allocation. Its implementation has shown that false alarms can be avoided and correct cylinder isolation is possible, also in presence of multiple misfires. Experimental tests have been performed on a 1.2 liter spark ignition engine mounted in a test cell. Various multiple misfire patterns have been induced by controlling ignition and injection of the various cylinders. In-cylinder pressure signals have been acquired together with the instantaneous engine speed, in order to verify the capability of the methodology.

scholarly journals A Nelder–Mead algorithm-based inverse transient analysis for leak detection and sizing in a single pipe

2021 ◽  
Author(s):  
Oussama Choura ◽  
Caterina Capponi ◽  
Silvia Meniconi ◽  
Sami Elaoud ◽  
Bruno Brunone
Keyword(s):  
Transient Analysis ◽  
Experimental Tests ◽  
Leak Detection ◽  
Calibration Procedure ◽  
Second Phase ◽  
Viscoelastic Parameters ◽  
The Difference ◽  
Single Pipe ◽  
The University ◽  
Nelder Mead Algorithm

Abstract In this paper the results of an experimental validation of a technique for leak detection in polymeric pipes based on the inverse transient analysis (ITA) are presented. In the proposed ITA the Nelder–Mead algorithm is used as a calibration tool. Experimental tests have been carried out in an intact and leaky high-density polyethylene (HDPE) single pipe installed at the Water Engineering Laboratory (WEL) of the University of Perugia, Italy. Transients have been generated by the fast and complete closure of a valve placed at the downstream end section of the pipe. In the first phase of the calibration procedure, the proposed algorithm has been used to estimate both the viscoelastic parameters of a generalized Kelvin–Voigt model and the unsteady-state friction coefficient, by minimizing the difference between the numerical and experimental results. In the second phase of the procedure, the calibrated model allowed the evaluation of leak size and location with an acceptable accuracy. Precisely, in terms of leak location the relative error was smaller than 5%.

Vibration Based Condition Monitoring of Helicopter Gearboxes Based on Cyclostationary Analysis

2019 ◽  
Author(s):  
Alexandre Mauricio ◽  
Linghao Zhou ◽  
David Mba ◽  
Konstantinos Gryllias
Keyword(s):  
Experimental Tests ◽  
Operational Reliability ◽  
Health Condition ◽  
Operating Conditions ◽  
False Alarms ◽  
Complex Structures ◽  
Planetary Gearbox ◽  
Bearing Defects ◽  
Envelope Spectrum ◽  
Selection Of

Abstract The core of a helicopter drivetrain is a complex planetary main gearbox (MGB) which reduces the high input speed generated by the engines in order to provide the appropriate torque to the main rotors and to other auxiliary systems. The gearbox consists of various shafts, planetary gears and bearings and operates under varying conditions under excessive friction, heat and high mechanical forces. The components are vulnerable to fatigue defects and therefore Health and Usage Monitoring Systems (HUMS) have been developed in order to monitor the health condition of the gearbox, focusing towards early, accurate and on time fault detection with limited false alarms and missed detections. The main aim of a HUM System is by health monitoring to enhance the helicopters’ operational reliability, to support the maintenance decision making, and to reduce the overall maintenance costs. The importance and the need for more advanced and accurate HUMS have been emphasized recently by the post-accident analysis of the helicopter LN-OJF, which crashed in Norway in 2016. During the last few decades various methodologies and diagnostic indicators/features have been proposed for the monitoring of rotating machinery operating under steady conditions but still there is no global solution for complex structures. A new tool called IESFOgram has been recently proposed by the authors, based on Cyclostationary Analysis, focusing on the accurate selection of a filtering band, under steady and varying speed conditions. Moreover the Cyclic Spectral Coherence is integrated along the selected frequency band leading to an Improved Envelope Spectrum. In this paper the performance of the tool is tested on a complex planetary gearbox, with several vibration sources. The method is tested, evaluated and compared to state of the art methods on a dataset captured during experimental tests under various operating conditions on a Category A Super Puma SA330 main planetary gearbox, presenting seeded bearing defects of different sizes.

Instantaneous Engine Speed Analysis for Cylinder Isolation in Multiple Misfire Events

2003 ◽  
Author(s):  
Fabrizio Ponti
Keyword(s):  
Torsional Vibration ◽  
Engine Speed ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Detection Methods ◽  
False Alarms ◽  
Time Interval ◽  
Short Time Interval ◽  
Operating Range ◽  
Misfire Detection

Misfire detection is a subject that has been deep studied during the last years and many methodologies have been developed for this purpose. Affordably detecting the misfire event and isolating the cylinder where the missing combustion took place can be considered a solved problem for engines with a limited number of cylinders. Misfire detection and in particular cylinder isolation is still challenging for engine operating conditions at very low load and high engine speed, for engines with a high number of cylinders, or when more than one misfire event is present within the same engine cycle (multiple misfire). In particular this last malfunctioning condition is very challenging, and its detection is enforced by the international regulations without requiring cylinder isolation, but only the number of misfiring cylinders. Many methodologies have been developed in the past based on the analysis of the instantaneous engine speed. The missing combustion effect on this signal is anyway very low when the number of cylinders is high and for engine operating conditions at low engine speed, giving rise to misdetection or false alarms as already mentioned. In addition when a misfire event takes place a torsional vibration is excited and shows up in the instantaneous engine speed waveform. If a multiple misfire occurs this torsional vibration is excited more than once in a very short time interval. The interaction among these successive vibrations can further generate false alarms or misdetection, and an increased complexity when dealing with cylinder isolation is necessary. The approach here presented permits enhancing existing misfire detection methods through optimized algorithm that allows correctly isolating the multiple misfiring cylinders over the entire engine operating range. This has been obtained by proper identifying the effect of the torsional vibration over the instantaneous engine speed. The identified waveform has been then used to filter out the torsional vibration effects in order to enlighten the effects of the missing combustions. In addition a proper instantaneous engine speed windowing has been introduced in order to increase the detection signal to noise ratio over the whole engine operating range. The integration of these two signal processing techniques has proven to be very effective on the engine investigated in this study, and it is easily extendible to other engine architectures. Particular care has been devoted to satisfy on-board implementation requirements in terms of memory allocation and computational power. The tests have been conducted on an L4 1.2 liter spark ignition engine mounted in a test cell. In-cylinder pressure signals have been acquired in order to validate the methodology here developed.

Instantaneous Engine Speed Time-Frequency Analysis for On-Board Misfire Detection and Cylinder Isolation in a V12 High Performance Engine

2002 ◽  
Author(s):  
Fabrizio Ponti
Keyword(s):  
Frequency Analysis ◽  
Engine Speed ◽  
Test Bench ◽  
Specific Pattern ◽  
Operating Conditions ◽  
False Alarms ◽  
Frequency Pattern ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Misfire Detection

The diagnosis of a misfire event and the isolation of the cylinder in which the misfire took place is enforced by the On Board Diagnostics (OBD) requirements over the whole operating range for all the vehicles whatever the configuration of the engine they mount. This task is particularly challenging for engines with a high number of cylinders and for engine operating conditions that are characterized by high engine speed and low load. This is why much research has been devoted to this topic in recent years, developing different detection methodologies based on signals such as instantaneous engine speed, exhaust pressure, etc., both in time and frequency domains. This paper presents the development and the validation of a methodology for misfire detection based on the time-frequency analysis of the instantaneous engine speed signal. This signal contains information related to the misfire event, since a misfire occurrence is characterized by a sudden engine speed decrease and a subsequent damped torsional vibration. The identification of a specific pattern in the instantaneous engine speed frequency content, characteristic of the system under study, allows performing the desired misfire detection and cylinder isolation. Particular attention has been devoted in designing the methodology in order to avoid the possibility of false alarms caused by the excitation of this frequency pattern independently from a misfire occurrence. Although the time-frequency analysis is usually considered a time consuming operation and is not associated to on-board application, the methodology here proposed has been properly modified and simplified in order to obtain the quickness required for its use directly on-board a vehicle. Experimental tests have been performed on a 5.7 liter V12 spark ignited engine, with the engine mounted on-board a vehicle. The frequency pattern identified is not the same that could be observed when running the engine on a test bench, because of the different stiffness that the connection between the engine and the load presents in the two cases. This makes impossible to set-up the methodology here proposed only on a test bench, without running tests on the vehicle.

Instantaneous Engine Speed Time-Frequency Analysis for Onboard Misfire Detection and Cylinder Isolation in a V12 High-Performance Engine

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Fabrizio Ponti
Keyword(s):  
Frequency Analysis ◽  
Engine Speed ◽  
Test Bench ◽  
Operating Conditions ◽  
False Alarms ◽  
Frequency Pattern ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Resonance Frequencies ◽  
Misfire Detection

The diagnosis of a misfire event and the isolation of the cylinder in which the misfire took place is enforced by the onboard diagnostics (OBD) requirements over the whole operating range for all the vehicles, whatever the configuration of the engine they mount. This task is particularly challenging for engines with a high number of cylinders and for engine operating conditions that are characterized by high engine speed and low load. This is why much research has been devoted to this topic in recent years, developing different detection methodologies based on signals such as instantaneous engine speed, exhaust pressure, etc., both in time and frequency domains. This paper presents the development and the validation of a methodology for misfire detection based on the time-frequency analysis of the instantaneous engine speed signal. This signal contains information related to the misfire event, since a misfire occurrence is characterized by a sudden engine speed decrease and a subsequent damped torsional vibration. The identification of a specific pattern in the instantaneous engine speed frequency content, characteristic of the system under study, allows performing the desired misfire detection and cylinder isolation. Particular attention has been devoted to designing the methodology in order to avoid the possibility of false alarms caused by the excitation of this frequency pattern independently from a misfire occurrence. Although the time-frequency analysis is usually considered a time-consuming operation and not associated to onboard application, the methodology proposed here has been properly modified and simplified in order to obtain the quickness required for its use directly onboard a vehicle. Experimental tests have been performed on a 5.7l V12 spark-ignited engine run onboard a vehicle. The frequency characteristic of the engine-vehicle system is not the same that could be observed when running the engine on a test bench, because of the different inertia and stiffness that the connection between the engine and the load presents in the two cases. This makes it impossible to test and validate the methodology proposed here only on a test bench, without running tests on the vehicle. Nevertheless, the knowledge of the mechanical design of the engine and driveline gives the possibility of determining the resonance frequencies of the system (the lowest one is always the most important for this work) before running tests on the vehicle. This allows saving time and reducing costs in developing the proposed approach.

Performance Analyses of the Spiral Groove Dry Gas Seal with Inner Annular Groove

2013 ◽  
Vol 420 ◽  
pp. 51-55 ◽  
Author(s):  
Ying Li ◽  
Peng Yun Song ◽  
Heng Jie Xu
Keyword(s):  
Pressure Control ◽  
Operating Conditions ◽  
Performance Parameters ◽  
Spiral Groove ◽  
Dry Gas Seal ◽  
Sealing Performance ◽  
The Common ◽  
The Difference ◽  
Film Stiffness ◽  
The Given

In order to improve the performance of the spiral groove dry gas seal (S-DGS), the spiral groove dry gas seal with an inner annular groove (AS-DGS) was invented. Based on the narrow groove theory, the sealing performance parameters of the AS-DGS were gained by using approximate analytical method to solve the gas film pressure control equations, and the results were compared with those of the common S-DGS. The results show that, in the given operating conditions, the opening force of AS-DGS is smaller than that of the S-DGS with the difference less than 0.5%, and the film stiffness is larger than that of the common S-DGS with the difference less than 5% in the case of low-speed or high-pressure operation, but the leakage is a little larger.

Performance investigation of an advanced diagnostic method for SSTPI-fed IM drives under single and multiple open IGBT faults

2019 ◽  
Vol 38 (2) ◽  
pp. 616-641 ◽  
Author(s):  
Mohamed Ali Zdiri ◽  
Badii Bouzidi ◽  
Hsan Hadj Abdallah
Keyword(s):  
Fault Detection ◽  
Diagnostic Method ◽  
Open Circuit ◽  
Operating Conditions ◽  
False Alarms ◽  
Content Type ◽  
Detection And Identification ◽  
Efficient Detection ◽  
Fault Detection And Identification ◽  
New Diagnosis

Purpose This paper aims to analyze and investigate the performance of an improved fault detection and identification (FDI) method based on multiple criteria, applied to six-switch three-phase inverter (SSTPI)-fed induction motor (IM) drives under both single and multiple open insulated-gate bipolar transistors(IGBT) faults. Design/methodology/approach This paper proposes an advanced diagnostic method for both single and multiple open IGBT faults dedicated to SSTPI-fed IM drives considering five distinct faulty operating conditions as follows: a single IGBT open-circuit fault, a single-phase open-circuit fault, a non-crossed double fault in two different legs, a crossed double fault in two different legs and a three-IGBT open-circuit fault. This is achieved because of the introduction of a new diagnosis variable provided using the information of the slope of the current vector in (α-β) frame. The proposed FDI method is based on the synthesis and the analysis, under both healthy and faulty operations, of the behaviors of the introduced diagnosis variable, the three motor phase currents and their normalized average values. Doing so, the developed FDI method allows a best compromise of fast detection and precision localization of IGBT open-circuit fault of the inverter. Findings Simulation works, carried out considering the implementation of the direct rotor flux oriented control in an IM fed by the conventional SSTPI, have proved the high performance of the advanced FDI method in terms of fast fault detection associated with a high robustness against false alarms, against speed and load torque fast variations and against the oscillations of the DC-bus voltage in the case of both healthy and faulty operations. Research limitations/implications This work should be extended considering the validation of the obtained simulation results through experiments. Originality/value Different from other FDI methods, which suffer from a low diagnostic effectiveness for low load levels and false alarms during transient operation, this method offers the potentialities to overcome these drawbacks because of the introduction of the new diagnosis variable. This latter, combined with the information provided from the three motor phase currents and their normalized average values allow a more efficient detection and identification of IGBT open-circuit fault.

Influence of Underbody Suspended Equipment on Rail Ride Comfort

2014 ◽  
Author(s):  
Roberto Corradi ◽  
Laura Mazzola ◽  
Francesco Ripamonti ◽  
Lorenzo Rosa
Keyword(s):  
Laboratory Test ◽  
Ride Comfort ◽  
Experimental Tests ◽  
Negative Influence ◽  
Point Of View ◽  
Operating Conditions ◽  
Elastic Behaviour ◽  
Test Results ◽  
Laboratory Test Results ◽  
The Common

This paper illustrates a methodology that, by means of laboratory and on-track tests, allows for an appropriate design of the connection elements between the suspended equipment and the carbody in order to enhance the rail ride comfort. In particular at first the connection elements are tested in laboratory to assess their visco-elastic behaviour simulating the common operating conditions. Subsequently on-track tests and experimental modal analysis are carried out to identify the interaction between underframe equipment motions and carbody modes. In the experimental tests, starting from the laboratory test results, it is possible to define the connection elements in order to minimise the negative influence on vehicle ride comfort. Two different solutions are proposed: the “TMD solution” (the suspension is tuned on the natural frequency of the carbody mode most relevant from the comfort point of view) and the “suspended solution” (the suspension system aims to decouple the two subsystems).

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