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Despite the degree of railway electrification in many EU countries is higher than 50%, the diesel-driven railway vehicles continue to play an important role. As known, internal combustion engines, especially diesel engines, have also long been recognized as a significant source of pollutant emissions contributing to poor air quality, negative human health impacts and climate change. The future emissions regulatory control programs and the fuel-saving requirements for the new diesel engines for railways applications push worldwide OEMs, suppliers and scientific communities to investigate more advanced and alternative propulsion systems in which the diesel engines could still play an important role. Thus, the design of new power trains becomes more challenging considering the even more strict emission and efficiency targets. In this context, numerical simulation represents an essential tool in the entire development and optimization process of power trains. This study focuses on the numerical assessment of three different models of the same engine, characterized by different model accuracy, in order to evaluate the trade-off between model accuracy and computational time. The evaluation is carried out by performing the new emission standard Non-Road Transient Cycle (NRTC) applying the EU Non-Road Mobile Machinery (NRMM) directive to rail diesel vehicles. This work considers a 560 kW Heavy-Duty (HD) diesel engine. Regarding the models, the second and the third model are derived from the first one through an appropriate numerical procedure. The first, more accurate 1D model, is adequate when a deeper system analysis is required (i.e. wave dynamics, turbo-matching, etc.), while, for the evaluation of the global performance, the simplest model approach is more appropriate for complex systems, such as a hybrid powertrain. Indeed, the simplest model, despite its lower accuracy, shows good predictive results in terms of cumulative fuel consumption and cumulative NOx emissions over a transient homologation cycle. Moreover, for the lowest model accuracy, the real time factor is significantly lower compared to the more detailed one of about 250 times.

Carbon dioxide (CO2), nitrogen oxides (NOx) and soot emissions are primary concerns and the most investigated topics in the automotive sector. Indeed, recent governments directives push toward carbon–neutral mobility by 2050. In this framework, zero-carbon fuels, as hydrogen, or renewable low carbon alcohol fuels, play a fundamental role. To this aim, in this chapter, the main results on largely used alcohol fuels application in spark-ignition (SI) engines are discussed. Aspects inherent ethanol and methanol production processes, chemical-physical properties and their application in SI engines are presented. Different engine fuelling strategies, dual fuel and blend are analysed. Alcohols have higher enthalpies of vaporisation and research octane number (RON) values as well as excellent anti-knock ability compared to gasoline. This effect enhances in dual fuel mode. Ethanol and methanol have higher thermodynamic conversion efficiencies than gasoline combustion. Cycle to cycle variation is in line with gasoline values. In general, NOx decreases with alcohol fuels, and the best results are achieved in blend mode with a reduction of up to 30% with methanol compared to gasoline. Independently of the fuelling mode, significant benefits on particle number emissions are observed by using alcohol fuels. Carbon monoxide (CO) and hydrocarbons (HC) emission trends strongly depend on fuelling mode and engine operating conditions. Additionally, the lower carbon content of alcohol fuels reduces the CO2 emissions up to 10% compared to reference gasoline.

The increasing concern of global warming due to the ever-increasing amount of greenhouse gases (GHG) such as carbon dioxide (CO2) and pollutant emissions induces regulatory authorities to stricter emission legislation in the transportation sector. In this context, renewable fuels, such as methanol and ethanol, are considered a promising solution to mitigate the carbon footprint and reduce engine-out emissions. Based on the several studies published in the specific literature, this work aims to summarise and normalize the main outcomes, highlighting the pro and cons of exerting alcohol fuels in compression ignition engines through a critical literature review for helping the researchers, who start to work on these applications. Both dual-fuel and direct-injection fuelling concepts of diesel and alcohol (ethanol and methanol) in compression ignition engines are discussed. Analyses on the combustion, emissions and performance and CO2 are carried out. Depending on the fuel supply method and the engine type, the use of alcohol fuels performs differently in terms of emissions and engine performance. Dual Fuel combustion mode, port fuel injected alcohol, and direct-injected diesel emits higher HC and CO, while diesel-alcohol blends perform as diesel. Generally, the blends characterized by lower alcohol concentration than dual-fuel perform higher indicated thermal efficiencies. Significant benefits on NOx-soot trade-offs are observed, independently on the fuelling mode, NOx concentration, and engine type by using alcohols. The soot reduction reaches values up to 70%, and the lower carbon content of alcohols fuel reduces the CO2 up to 15%.

Il presente documento fa riferimento alle attività di consulenza svolte dall'Istituto Motori del Consiglio Nazionale delle Ricerche, per la Costruzioni Motori Diesel S.p.A. - CMD nell'ambito dell'OR 6 - "Integrazione, caratterizzazione sperimentale dei componenti ed analisi delle prestazioni al banco prova del propulsore ibrido" facente parte del progetto iMare. Nella prima parte sono riportate le attività indirizzate all'allestimento della sala prova motore presso la sede della CMD ad Atella (Pz), dove verrà poi alloggiato il sistema ibrido messo a punto per le successive prove al banco. In tale sezione sarà riportata una descrizione della sala prova nonché degli elementi costituenti la catena di acquisizione/controllo dei principali parametri meccanici ed elettrici. La seconda parte del report verte sulla discussione delle strategie di gestione del sistema di propulsione ibrido. In particolare l'attività è rivolta allo sviluppo ed alla simulazione numerica di differenti strategie di controllo al fine di valutarne pregi e difetti una volta fissate opportune condizioni operative replicabili poi sul sistema in scala reale come previsto dagli altri OR relativi al progetto iMare. Nella terza parte del report, sono invece riportati i risultati sperimentali ottenuti al banco prova sul sistema di propulsione prototipale. In particolare, la prima parte delle prove è stata dedicata all'allestimento del sistema di comunicazione CANBUS ed alla verifica del suo corretto funzionamento in diverse condizioni operative. Le prove successive sono state rivolte all'esecuzione dei test al banco per il sistema di propulsione ibrido, in condizioni operative rappresentative del suo funzionamento a bordo.

The transportation sector is one of the main contributors to global CO2 emissions and is expected to further increase due to the growth of population and life quality standards. Therefore, reduction CO2 emissions is the top priority to prevent the negative impacts of climate change. For these reasons, the automotive sector is facing new challenges, advanced internal combustion engines, electrification of the drive train, replacing fossil fuels can help to meet greenhouse gas emission standards and simultaneously reduce pollutants. In this study, two ethanol fueling modes, dual fuel and blend, are applied in a compression ignition engine to evaluate the effect of different engine calibration parameters on the thermodynamic and emissions. A parametric analysis is conducted for the variables, fuel substitution ratio, injection pattern, fuel injection pressure, and exhaust gas recirculation. The results demonstrate ethanol being a promising alternative to fossil fuels for the globally lower emissions in compliance with the actual advanced engine technologies. Ethanol blend improves the gross-indicated efficiency compared to the dual-fuel and diesel combustion. However, the dual-fuel emitted higher THC and CO emissions than in diesel and blend cases that have comparable levels. Ethanol blends combustion with a high level of ethanol, and EGR employing a multi-injection strategy shows a positive impact on emission reduction while maintaining high efficiency compared to the dual-fuel and diesel combustion. The dual-fuel combustion employing high ethanol, rail pressure, and EGR levels leads to important benefits, minimizing the emissions and noise and maximizing the efficiency.

Il presente documento fa riferimento alle attività di consulenza svolte dall'Istituto di Scienze e Tecnologie per l'Energia e la Mobilità Sostenibili del Consiglio Nazionale delle Ricerche (CNR[1]STEMS) per la Costruzioni Motori Diesel S.p.A. - CMD nell'ambito dell'OR 8 - "Messa a punto del sistema ibrido di propulsione installato su un dimostratore tipo di imbarcazione fino a 10 m" del progetto iMare. Tali attività sono state concordate tra le parti, come riportato nel contratto di consulenza stipulato in data 07/05/2019 con protocollo IM-CNR 1339 del 28/05/2019. Il documento è suddiviso in due sezioni, seguendo gli obiettivi realizzativi previsti dall'OR 8 del progetto iMare. Nella prima parte del report si riportano le attività svolte presso il cantiere nautico Salpa, sito in Vitulazio (CE). Tali attività, svolte a valle dell'installazione on-board, sono state utili alla configurazione e testing del sistema di propulsione ibrido prototipale e dei relativi sistemi ausiliari. A valle della fase di testing della componentistica prevista sono inoltre riportate le attività svolte in vasca, indispensabili per il varo finale e le successive prove in mare. La seconda parte del report riporta i risultati delle prove a mare, svolte presso la banchina del Porto di Pozzuoli, con l'obiettivo di verificare le prestazioni dell'imbarcazione nelle principali condizioni di funzionamento previste da progetto.

Graphene-coated membranes for membrane distillation have been fabricated by using a wet-filtration approach. Graphene nanoplatelets have been deposited onto PVDF membrane surfaces. Morphology and physicochemical properties have been explored to evaluate the changes in the surface topography and related effects on the membrane performance in water desalination. The membranes have been tested in membrane distillation plants by using mixtures of sodium chloride and humic acid. The multi-scale rough structure of the surface has been envisaged to amplify the wetting and fouling resistance of the graphene-coated membranes so that a better flux and full salt rejection have been achieved in comparison with pristine PVDF. Total salt rejection and an increase of 77% in flux have been observed for coated membrane with optimized graphene content when worked with NaCl 0.6 M (DCMD, ΔT ≈ 24 °C) over a test period of 6 h. The experimental findings suggest these novel graphene-coated membranes as promising materials to develop functional membranes for high-performing water desalination.

Compression ignition (CI) engines are widely used in modern society, but they are also recognized as a significative source of harmful and human hazard emissions such as particulate matter (PM) and nitrogen oxides (NOx). Moreover, the combustion of fossil fuels is related to the growing amount of greenhouse gas (GHG) emissions, such as carbon dioxide (CO2). Stringent emission regulatory programs, the transition to cleaner and more advanced powertrains and the use of lower carbon fuels are driving forces for the improvement of diesel engines in terms of overall efficiency and engine-out emissions. Ethanol, a light alcohol and lower carbon fuel, is a promising alternative fuel applicable in the dual-fuel (DF) combustion mode to mitigate CO2 and also engine-out PM emissions. In this context, this work aims to assess the maximum fuel substitution ratio (FSR) and the impact on CO2 and PM emissions of different nozzle holes number injectors, 7 and 9, in the DF operating mode. The analysis was conducted within engine working constraints and considered the influence on maximum FSR of calibration parameters, such as combustion phasing, rail pressure, injection pattern and exhaust gas recirculation (EGR). The experimental tests were carried out on a single-cylinder light-duty CI engine with ethanol introduced via port fuel injection (PFI) and direct injection of diesel in two operating points, 1500 and 2000 rpm and at 5 and 8 bar of brake mean effective pressure (BMEP), respectively. Noise and the coefficient of variation in indicated mean effective pressure (COVIMEP) limits have been chosen as practical constraints. In particular, the experimental analysis assesses for each parameter or their combination the highest ethanol fraction that can be injected. To discriminate the effect on ethanol fraction and the combustion process of each parameter, a one-at-a-time-factor approach was used. The results show that, in both operating points, the EGR reduces the maximum ethanol fraction injectable, nevertheless, the ethanol addition leads to outstanding improvement in terms of engine-out PM. The adoption of a 9 hole diesel injector, for lower load, allows reaching a higher fraction of ethanol in all test conditions with an improvement in combustion noise, on average 3 dBA, while near-zero PM emissions and a reduction can be noticed, on the average of 1 g/kWh, and CO2 compared with the fewer nozzle holes case. Increasing the load insensitivity to different holes number was observed.

Il presente documento riporta si riporta una descrizione delle attività del CNR-Istituto Motori con rispettivo riferimento all'OR1.1 - Analisi e definizione dell'imbarcazione e del profilo di utilizzo: definizione della potenza termica ed elettrica da impegnare, in funzione dell'autonomia modalità elettrica e termica di navigazione ed all'OR1.2 - Analisi e definizione delle strategie di gestione dei flussi energetici del sistema di propulsione ibrido per le fasi di navigazione. le attività sono state rivolte a contestualizzare l'impiego di architetture di propulsione ibride di tipo navale, nell'ambito dell'attuale scenario normativo Europeo, incentrato sulla riduzione dell'impatto ambientale e sul miglioramento dell'efficienza della mobilità marittima. Parallelamente è stata svolta un'analisi delle principali strategie di gestione dei flussi energetici, tra sistema di accumulo e motorizzazioni termico/elettriche, per l'ottimizzazione di architetture di propulsione ibride, di impiego in ambito navale