Real-Time Engine Diagnostic and Control Based on Acoustic Emissions Analysis

Engine developers are putting more and more emphasis on the research of maximum thermal and mechanical efficiency in the recent years. Research advances have proven the effectiveness of downsized, turbocharged and direct injection concepts, applied to gasoline combustion systems, to reduce the overall fuel consumption while respecting exhaust emissions limits. These new technologies require more complex engine control units. The sound emitted from a mechanical system encloses many information related to its operating condition and it can be used for control and diagnostic purposes. The thesis shows how the functions carried out from different and specific sensors usually present on-board, can be executed, at the same time, using only one multifunction sensor based on low-cost microphone technology. A theoretical background about sound and signal processing is provided in chapter 1. In modern turbocharged downsized GDI engines, the achievement of maximum thermal efficiency is precluded by the occurrence of knock. Knock emits an unmistakable sound perceived by the human ear like a clink. In chapter 2, the possibility of using this characteristic sound for knock control propose, starting from first experimental assessment tests, to the implementation in a real, production-type engine control unit will be shown. Chapter 3 focus is on misfire detection. Putting emphasis on the low frequency domain of the engine sound spectrum, features related to each combustion cycle of each cylinder can be identified and isolated. An innovative approach to misfire detection, which presents the advantage of not being affected by the road and driveline conditions is introduced. A preliminary study of air path leak detection techniques based on acoustic emissions analysis has been developed, and the first experimental results are shown in chapter 4. Finally, in chapter 5, an innovative detection methodology, based on engine vibration analysis, that can provide useful information about combustion phase is reported.Negli ultimi anni, nel panorama automobilistico mondiale è stata introdotta una nuova generazione di motori, che rappresentano la ricerca della massima efficienza termica e meccanica. Numerose ricerche hanno dimostrato l'efficacia dei concetti di iniezione diretta, riduzione della cilindrata, sovralimentazione applicate a sistemi di combustione ad accensione comandata, per ridurre il consumo e rispettare i limiti di emissioni. Queste nuove tecnologie richiedono sistemi di gestione sempre più complessi. Il suono emesso da un sistema meccanico racchiude molte informazioni relative alla sua condizione operativa e attraverso una opportuna elaborazione può essere utilizzato con finalità di controllo e diagnostica. Nella tesi verrà mostrato come funzioni specifiche svolte da sensori differenti presenti in vettura, possono essere eseguite tramite un unico sensore multifunzione basato su una tecnologia microfonica a basso costo. Il primo capitolo introdurrà alcune nozioni di acustica e del trattamento dei segnali. Il capitolo 2 illustra lo sviluppo di indici di detonazione basati sull’elaborazione del segnale acustico applicati sia a motori automobilisti che motociclistici. Questa tecnica di identificazione è stata implementata in una reale centralina di produzione. Nel terzo capitolo viene analizzata la capacità di rilevamento di mancate accensioni mediante l’analisi sonora. Nel dominio delle basse frequenze sonore, è possibile individuare caratteristiche relative a ciascun ciclo di combustione di ogni cilindro. Il vantaggio presentato da questa metodologia di identificazione è di non essere influenzato dalle condizioni della linea di trasmissione e della strada, come invece accade per la tecnologia più largamente utilizzata, che è basata sull’analisi della velocità istantanea dell’albero motore. Nel capitolo 4 vengono mostrati i primi studi e risultati sperimentali nello sviluppo di una tecnica di identificazione di perdite del giro aria mediante analisi acustica. Nel capitolo 5 verrà descritta una metodologia di analisi innovativa del segnale accelerometrico in grado di fornire informazioni utili per la determinazione della fase di combustione

Alzheimer's Disease Promotion by Obesity: Induced Mechanisms—Molecular Links and Perspectives

The incidence of AD is increasing in parallel with the increase in life expectancy. At the same time the prevalence of metabolic syndrome and obesity is reaching epidemic proportions in western populations. Stress is one of the major inducers of visceral fat and obesity development, underlying accelerated aging processes. Adipose tissue is at present considered as an active endocrine organ, producing important mediators involved in metabolism regulation as well as in inflammatory mechanisms. Insulin and leptin resistance has been related to the dysregulation of energy balance and to the induction of a chronic inflammatory status which have been recognized as important cofactors in cognitive impairment and AD initiation and progression. The aim of this paper is to disclose the correlation between the onset and progression of AD and the stress-induced changes in lifestyle, leading to overnutrition and reduced physical activity, ending with metabolic syndrome and obesity. The involved molecular mechanisms will be briefly discussed, and advisable guide lines for the prevention of AD through lifestyle modifications will be proposed

Analysis of Pre-ignition Combustions Triggered by Heavy Knocking Events in a Turbocharged GDI Engine

Abstract In this paper, a pre-ignition sequence with detrimental effects on the engine has been analysed and described, with the aim of identifying the main parameters involved in damaging the combustion chamber components. The experiment was carried out in a wider research context, focused on knock damage mechanisms in turbocharged GDI engines. The pre-ignition sequence was a consequence of a high knock condition, induced at high load at 4500 rpm. The abnormal thermal load due to knock caused overheating of the whole combustion chamber, until the spark plug electrodes became a "hot spot", resulting in premature flame initiation in the following cycles, with a self-sustaining mechanism. Slight cylindrical differences, mainly in terms of volumetric efficiency, allowed comparisons and correlations between indicated parameters, pre-ignition sequence and damage. The main responsible in damaging the engine, in this case and for this engine, is the extremely high heat transferred to the walls in the pre-ignited cycles, characterized by higher mean temperatures. Heavy knock triggered the pre-ignited combustions but progressively reduced its intensity as the spontaneous ignition advance increased, thus having a secondary role in damaging directly the combustion chamber

Combustion and Intake/Exhaust Systems Diagnosis Based on Acoustic Emissions of a GDI TC Engine

Abstract Due to increasingly stringent emission regulations and the need for more efficient powertrains, engine control systems that have been developed during the recent years have become more and more sophisticated. Obtaining accurate information about the combustion process and about all the subsystems that compose the engine can be considered key to reach the maximum overall performance. Low-cost in-cylinder pressure and turbo speed sensors are being developed, but they still present long-term reliability issues, and represent a considerable part of the entire engine management system cost. Sound emissions represent an extremely rich information source about the operating conditions of all the subsystems that comprise the entire engine. The paper shows how it is possible to extract fundamental information regarding the combustion process (such as knock and misfire), turbo speed, and air path fault at the same time, by performing an appropriate analysis of the engine acoustic emissions acquired from the very same microphone, which can thus be considered as an innovative, multifunction, and low-cost sensor for automotive applications

Accelerometer Based Methodology for Combustion Parameters Estimation

Due to increasingly stringent emission regulations and the need of more efficient powertrains, obtaining information about combustion process becomes a key factor. Low-cost in-cylinder pressure sensors are being developed, but they still present longterm reliability issues, and represent a considerable part of the engine management system cost. Research is being conducted in order to develop methodologies for extracting relevant combustion information using standard sensors already installed on-board. The present work introduces a methodology for combustion parameters estimation, through a control-oriented analysis of structureborne sound. The paper also shows experimental results obtained applying the estimation methodology to different passenger car engines. © 2015 The Authors. Published by Elsevier Ltd

Multidisciplinary Approaches to the stimulation of Wound Healing and Use of Dermal Substitutes in Chronic Phlebostatic Ulcers

Research focus: Skin injuries are evolving as an epidemic issue. Chronic skin lesion is a globally widespread disease, often referred to as a “wound difficult to heal" and one which has a strong impact on both overall health and quality of life. Genetic and clinical variables, such as diabetes, smoking, and inflammatory/immunological pathologies, are among the important risk factors limiting the regenerative powers of many therapeutic applications. Therefore, optimisation of current clinical strategies is critical. Experimental research: here we summarise the field’s current state by focusing on the use of stem-cell therapeutic applications in wound healing, placing considerable emphasis on current clinical approaches being developed at Rome’s Sapienza University. These involve protocols for the ex-vivo expansion of adipose tissue-derived mesenchyme stem cells using a patented GMP-compliant platelet lysate, Mesengen™, and cellular and a-cellulated dermal substitutes. A combination of multiple strategies, including genetic modifications of stem cells, biomimetic scaffolds, or novel vehicles like nanoparticles, are also discussed as future approaches. Case studies: here we present a report portraying our clinical experience of the treatment of chronic phlebostatic ulcers. The aim of the study reported here was to evaluate the effectiveness of treatment with dermal substitutes of cutaneous lesions originating from chronic venous insufficiency, therapy which took into consideration parameters such as: the reduction of wound size and the improvement of quality of life. Chronic skin lesion, a globally widespread disease, is often referred to as a "difficult wound" and has a strong impact on both overall health and quality of life. The difficulties encountered when seeking to heal this ailment have led to a quest for and development of new therapeutic approaches, including dermal substitutes. We can subdivide these into a-cellular matrices, such as Integra and Hyalomatrix and cell therapies such as Platelet Concentrate and Mesenchyme Cell Concentrate. Results: in all the patients treated, elements of improvement were observed: the appearance on the wound bed of small islands of granulation tissue, superficialization of the bottom of the ulcer and a growth of marginal tissue. During the first 30 days a reduction of more than 25% of the area of the lesion and a reduction of more than 50% at the end of the observation period were recorded in 10 of the patients who underwent preliminary surgical treatment out of the 13 subjects included in the study sample. On the whole, at the end of the observation period we witnessed an average 57% decrease of the lesion in all the patients; furthermore, during the treatment period, there was a gradual reduction of pain, measured using the NRS numerical scale. An overall average reduction in pain of 4 points on the NRS numerical scale was achieved. At the end of the eight-week evaluation period, the majority of the patients reported an improvement in the quality of their lives, since, in addition to the reduction of spontaneous pain, there was a diminution of pruritus, secretions -often malodorous and capable of affecting social life negatively - with recovery of functional capacity and almost complete recovery of habitual daily activities. During the period of treatment, no super-infections of the wounds or secondary complications related to the use of the various products were detected. Main conclusions. The numerous technological opportunities provided by regenerative medicine -including advanced dressings and dermal substitutes- if applied correctly, in compliance with a multidisciplinary approach where necessary, seem to offer advantages in terms of not only of clinical efficacy and patient life-quality but also in terms, it would appear, of health-care costs, an aspect which should not be either overlooked or underestimated

Multidisciplinary Approaches to the Stimulation of Wound Healing and Use of Dermal Substitutes in Chronic Phlebostatic Ulcers

Research focus: Skin injuries are evolving as an epidemic issue. Chronic skin lesion is a globally widespread disease, often referred to as a “wound difficult to heal” and one which has a strong impact on both overall health and quality of life. Genetic and clinical variables, such as diabetes, smoking and inflammatory/immunological pathologies, are among the important risk factors limiting the regenerative powers of many therapeutic applications. Therefore, optimisation of current clinical strategies is critical. Experimental research: Here we summarise the field’s current state by focusing on the use of stem-cell therapeutic applications in wound healing, placing considerable emphasis on current clinical approaches being developed at Rome’s Sapienza University. These involve protocols for the ex vivo expansion of adipose tissue-derived mesenchyme stem cells using a patented GMP-compliant platelet lysate, Mesengen™, and cellular and acellular dermal substitutes. A combination of multiple strategies, including genetic modifications of stem cells, biomimetic scaffolds or novel vehicles like nanoparticles, is also discussed as future approaches. Case studies: Here we present a report portraying our clinical experience of the treatment of chronic phlebostatic ulcers. The aim of the study reported here was to evaluate the effectiveness of treatment with dermal substitutes of cutaneous lesions originating from chronic venous insufficiency, therapy which took into consideration parameters such as the reduction of wound size and the improvement of quality of life. Chronic skin lesion, a globally widespread disease, is often referred to as a “difficult wound” and has a strong impact on both overall health and quality of life. The difficulties encountered when seeking to heal this ailment have led to a quest for and development of new therapeutic approaches, including dermal substitutes. We can subdivide these into acellular matrices, such as Integra and Hyalomatrix, and cell therapies such as platelet concentrate and mesenchyme cell concentrate. Results: In all the patients treated, elements of improvement were observed: the appearance on the wound bed of small islands of granulation tissue, superficialization of the bottom of the ulcer and a growth of marginal tissue. During the first 30 days, a reduction in more than 25% of the area of the lesion and a reduction in more than 50% at the end of the observation period were recorded in 10 of the patients who underwent preliminary surgical treatment out of the 13 subjects included in the study sample. On the whole, at the end of the observation period, we witnessed an average 57% decrease in the lesion in all the patients; furthermore, during the treatment period, there was a gradual reduction in pain, measured using the NRS numerical scale. An overall average reduction in pain of four points on the NRS numerical scale was achieved. At the end of the 8-week evaluation period, the majority of the patients reported an improvement in the quality of their lives, since, in addition to the reduction of spontaneous pain, there was a diminution of pruritus, secretions—often malodorous and capable of affecting social life negatively—with recovery of functional capacity and almost complete recovery of habitual daily activities. During the period of treatment, no superinfections of the wounds or secondary complications related to the use of the various products were detected. Main conclusions: The numerous technological opportunities provided by regenerative medicine—including advanced dressings and dermal substitutes—if applied correctly, in compliance with a multidisciplinary approach where necessary, seem to offer advantages not only in terms of clinical efficacy and patient life quality but also in terms, it would appear, of healthcare costs, an aspect which should not be either overlooked or underestimated

Perinatal S-Adenosylmethionine Supplementation Represses PSEN1 Expression by the Cellular Epigenetic Memory of CpG and Non-CpG Methylation in Adult TgCRD8 Mice

DNA methylation, the main epigenetic modification regulating gene expression, plays a role in the pathophysiology of neurodegeneration. Previous evidence indicates that 50 -flanking hypomethylation of PSEN1, a gene involved in the amyloidogenic pathway in Alzheimer’s dis- ease (AD), boosts the AD-like phenotype in transgenic TgCRND8 mice. Supplementation with S-adenosylmethionine (SAM), the methyl donor in the DNA methylation reactions, reverts the patho- logical phenotype. Several studies indicate that epigenetic signatures, driving the shift between normal and diseased aging, can be acquired during the first stages of life, even in utero, and manifest phenotypically later on in life. Therefore, we decided to test whether SAM supplementation during the perinatal period (i.e., supplementing the mothers from mating to weaning) could exert a protec- tive role towards AD-like symptom manifestation. We therefore compared the effect of post-weaning vs. perinatal SAM treatment in TgCRND8 mice by assessing PSEN1 methylation and expression and the development of amyloid plaques. We found that short-term perinatal supplementation was as effective as the longer post-weaning supplementation in repressing PSEN1 expression and amyloid deposition in adult mice. These results highlight the importance of epigenetic memory and methyl donor availability during early life to promote healthy aging and stress the functional role of non-CpG methylation

RFC1 expansions are a common cause of idiopathic sensory neuropathy

After extensive evaluation, one-third of patients affected by polyneuropathy remain undiagnosed and are labelled as having chronic idiopathic axonal polyneuropathy, which refers to a sensory or sensory-motor, axonal, slowly progressive neuropathy of unknown origin. Since a sensory neuropathy/neuronopathy is identified in all patients with genetically confirmed RFC1 cerebellar ataxia, neuropathy, vestibular areflexia syndrome, we speculated that RFC1 expansions could underlie a fraction of idiopathic sensory neuropathies also diagnosed as chronic idiopathic axonal polyneuropathy. We retrospectively identified 225 patients diagnosed with chronic idiopathic axonal polyneuropathy (125 sensory neuropathy, 100 sensory-motor neuropathy) from our general neuropathy clinics in Italy and the UK. All patients underwent full neurological evaluation and a blood sample was collected for RFC1 testing. Biallelic RFC1 expansions were identified in 43 patients (34%) with sensory neuropathy and in none with sensory-motor neuropathy. Forty-two per cent of RFC1-positive patients had isolated sensory neuropathy or sensory neuropathy with chronic cough, while vestibular and/or cerebellar involvement, often subclinical, were identified at examination in 58%. Although the sensory ganglia are the primary pathological target of the disease, the sensory impairment was typically worse distally and symmetric, while gait and limb ataxia were absent in two-thirds of the cases. Sensory amplitudes were either globally absent (26%) or reduced in a length-dependent (30%) or non-length dependent pattern (44%). A quarter of RFC1-positive patients had previously received an alternative diagnosis, including Sj\uf6gren's syndrome, sensory chronic inflammatory demyelinating polyneuropathy and paraneoplastic neuropathy, while three cases had been treated with immune therapies

Abstracts from the 20th International Symposium on Signal Transduction at the Blood-Brain Barriers

https://deepblue.lib.umich.edu/bitstream/2027.42/138963/1/12987_2017_Article_71.pd