Reduction Of Particulate Emissions Research Articles

Exploiting Lubricant Formulation to Reduce Particle Emissions from Gas Powered Engines

The present paper illustrates the results of an experimental study aimed at evaluating the effect of lubricant oil features on the emissive behaviour of a heavy duty spark ignition engine fuelled with methane. The activity was performed within a research project between CNR-STEMS and TotalEnergies in which oils with different formulations were characterized, focusing on their potentiality in particle emission reduction. Considering the ultralow particle emission level in the exhaust of gas engines, a specific testing procedure was designed to guarantee highly reliable and accurate results. In particular, the engine was operated under transient conditions, along the World Harmonized Transient Cycle in cold- and hot-start conditions. The results of the test campaign clearly highlight that the lubricant formulation is a key technology for the control of particles, revealing this as an important aspect in view of the upcoming severe regulation limits on particle emissions. The experimental findings show the capability of reformulated oils to drop down the total particle number to 60–70% with respect to a baseline standard oil. The interest in the present study also lies in providing information extendable to more sustainable fuels, like hydrogen or biomethane, nowadays of great interest as alternative energy sources.

Effects of continuous variable valve timing and duration on fuel/air mixture formation

With increasing global regulations on particulate emissions, the particulate matter and number released under cold start and high-load conditions have become crucial. Under such conditions, the particulate emissions from port fuel injection engines can be significant and comparable to those from gasoline direct injection engines. In this case, fuel evaporation and mixture formation contribute to the reduction in particulate emissions. One method to improve these characteristics is to enhance the in-cylinder flow and turbulence kinetic energy. Therefore, in this study, we investigated the effect of in-cylinder flow enhancement on the particulate emissions reduction in port fuel injection engines. Simulations were conducted with various intake valve timings and durations under cold-start conditions. We then performed engine experiments to confirm the reduction in particulate number. The results showed that the relationship between the intake valve open timing and piston speed was crucial. Opening the intake valve to its maximum value slightly after the point of peak piston velocity resulted in a higher flow intensity and turbulence kinetic energy during the compression stroke. In addition, the experimental results indicated that improving the in-cylinder flow using continuous variable valve timing reduced the particulate number by 27.51 %.

Assessing Particulate Emissions of Novel Synthetic Fuels and Fossil Fuels under Different Operating Conditions of a Marine Engine and the Impact of a Closed-Loop Scrubber

Particle emissions from marine activities next to gaseous emissions have attracted increasing attention in recent years, whether in the form of black carbon for its contribution to global warming or as fine particulate matter posing a threat to human health. Coastal areas are particularly affected by this. Hence, there is a great need for shipping to explore alternative fuels that both reduce greenhouse gas emissions, as anticipated through IMO, and also have the potential to reduce particle emissions significantly. This paper presents a comparative study of the particulate emissions of two novel synthetic/biofuels (GTL and HVO), which might, in part, substitute traditionally used distillate liquid fuels (e.g., MDO). HFO particulate emissions, in combination with an EGCS, formed the baseline. The main emphasis was laid on particle concentration (PN) and particulate matter (PM) emissions, combining gravimetric and particle number measurements. Measurements were conducted on a 0.72 MW research engine at different loads (25%, 50%, and 75%). The results show that novel fuels produce slightly fewer emissions than diesel fuel. Results also exhibit a clear trend that particle formation decreases as engine load increases. The EGCS only moderately reduces particle emissions for all complaint fuels, which is related to the formation of very fine particles, especially at high engine loads.

Impacts of fuelling methods on knock-limited combustion and emissions of a dedicated hybrid spark-ignition engine

This study investigates the impact of various fuelling methods on knock-limited combustion efficiency and emissions in a high compression ratio, turbocharged spark-ignition gasoline engine designed for hybrid applications. Different injection strategies, including port fuel injection (PFI), direct injection (DI), two-stage DI, PFI with late DI, and PFI with in-cylinder targeted fuel injection (TFI), were evaluated. TFI, a novel method where fuel is injected towards knock-prone regions based on knock spatial distribution, was seen capable of advancing the knock-limited spark advance (KLSA) by up to 3.75°, and hence reducing fuel consumption by 18.78 g/kWh, demonstrating significant knock suppression. Furthermore, trade-off characteristics between fuel consumption and particulate emissions resulting from injection strategies were exhibited from the measured data. DI produces the optimal fuel consumption and the worst particulate emissions, while PFI shows the opposite. Importantly, TFI improves the trade-off, reducing fuel consumption and emissions simultaneously. The refined TFI achieved a 96.6 % reduction in particulate emissions compared to DI, matching PFI levels while improving engine thermal efficiency. These different combustion characteristics are attributed to the localized fuel–air mixing and charge cooling affected by injection strategies.

Seawater source heat pump system based on capillary heat exchanger for seepage in submarine tunnel: a case study

Abstract The discharge of seepage water from undersea tunnel structures, often treated as wastewater, inherently carries a substantial reservoir of untapped low-grade thermal energy. Unfortunately, comprehensive investigations into harnessing this latent potential remain notably limited. This study introduced an innovative strategy through the design of an undersea tunnel seepage seawater source heat pump system. Distinguished by the integration of a capillary front-end heat exchanger, this system aimed to effectively exploit the frequently disregarded low-grade thermal energy present in the seepage water of undersea tunnel structures. The seawater seepage from the tunnel is transported to the car park at the tunnel entrance, and a seawater energy pool is constructed by storing seawater in its underground space. The use of capillary network placed in the energy pool in the front heat exchanger, water source heat pump units, circulating water pumps and fan coil end device composed of underground undersea tunnel seepage seawater source heat pump system for the building heating and cooling. Furthermore, a comparative assessment was conducted, contrasting this novel system with the traditional air-conditioning setup that utilizes chillers and gas boilers as cooling and heating sources. The aim was to evaluate its capacity for energy conservation and emission reduction. The findings from the study strongly affirmed the viability of the proposed seepage seawater source heat pump system within undersea tunnels. It boasted the potential to achieve annual savings of 53.55 tce, highlighting a noteworthy energy-saving rate of 21.2%. Concurrently, reductions in CO2, SO2, and particulate emissions amounted to 132.28 t/a, 1.07 t/a, and 0.54 t/a, respectively. This study not only stands as a reference for the strategic utilization of seepage seawater from undersea tunnel structures, prioritizing energy conservation and emission reduction, but also pioneers innovative approaches toward resource optimization and environmental sustainability, meeting the inherent needs of carbon peaking and carbon neutrality goals.

Advancing Fuel Spray Characterization: A Machine Learning Approach for Directly Injected Gasoline Fuel Sprays

Compression ignition engines when operated on gasoline fuels cause significant reduction in NOx and particulate emissions. In such advanced combustion strategy, the fuel-oxidiser mixing process, intensified by the prolonged ignition delays of gasoline fuels, directly affects the stability and efficiency of combustion. Thus, optimising fuel spray characteristics leads to optimisation of injector design, engine performance and subsequent decrease in emissions. Since spray development is a complex process that involves wide range of length and time scales, computationally expensive modelling techniques can be replaced with machine learning (ML) models. These ML models are employed to predict spray characteristics utilizing datasets generated from comprehensive spray studies. In this work, a dataset of about 5400 instances taken from non-evaporating gasoline fuel spray imaging experiments under Gasoline Compression Injection (GCI) engine conditions is used to train various ML models with data split of 70 % and 30 % for training and testing, respectively, with five-folds cross-validation performed within the training. The fuel injection pressure (60 – 150 MPa), chamber pressure (0.1 – 2 MPa), nozzle diameter, nozzle hole conicity and injection duration are used as input features to the models for predicting the spray tip penetration and spray angle. The performance of four ML models was evaluated and compared under default and tuned hyperparameters against experimental data and available physics-based correlations in the literature. The models include random forest, extreme gradient boosting, multilayer perceptron, and elastic-net. The results show that the hyperparameter-tuned extreme gradient boosting model performs best in predicting the spray parameters. The overall model performance was evaluated using the coefficient of determination (R2), mean absolute error (MAE), and root mean squared error (RMSE), resulting in values of 0.884, 0.651, and 1.571, respectively. This study presents compelling evidence demonstrating the effectiveness of ML as a powerful tool for isolating non-linear behaviors from physical processes. By effectively decoupling these behaviors, ML enhances the accuracy of predicting spray characteristics while significantly reducing computational costs. The application of ML in fuel injector design has the potential to revolutionize engine performance and contribute to substantial reductions in emissions.

Effects of Diesel Emissions on Black Carbon and Particle Number Concentrations in the Eastern U.S.

The effects of emissions of diesel engines on black carbon and particle number concentrations, as well as climate-relevant aerosol properties, are explored for a summertime period in the Eastern U.S. using the chemical transport model PMCAMx-UF. A 50% reduction in diesel particulate emissions results in lower (23%) black carbon mass concentrations, as expected, and similar changes both in magnitude (27–30%) and spatial pattern for the absorption coefficient. However, an average 2% increase in the total particle number concentrations is predicted due to a decrease in the coagulation and condensation sinks and, at the same time, a 2% decrease in N100 (particles larger than 100 nm) concentrations. The diesel reduction results suggest that mitigation of large diesel particles and/or particle mass emissions can reduce climate-relevant properties related to the absorption of black carbon and provide health benefits; however, the changes could also have the unintended effect of increased ultrafine particle number concentrations. Changes in cloud condensation nuclei are predicted to be significantly less than expected, assuming a proportional reduction during this photochemically active period. Doubling the diesel emissions results in a domain-averaged 3% decrease in total particle number concentrations and a 3% increase in N100 concentrations. PM2.5 BC concentrations increase on average by 46%, and similar changes (52–60%) are predicted for the absorption coefficient. Extinction coefficients for both perturbation simulations changed by only a few percent due to the dominance of scattering aerosols in the Eastern U.S. during this period characterized by high photochemical activity.

Influence of operational variables of the catalytic cracking unit on the circulation of the catalyst at constant mass conversion: Acting on the reduction of particulate emissions

Influence of operational variables of the catalytic cracking unit on the circulation of the catalyst at constant mass conversion: Acting on the reduction of particulate emissions

Effect of Fuel Injection Strategies on Performance, Regulated and Unregulated Emissions of a Gasoline Compression Ignition Engine

Abstract Gasoline compression ignition (GCI) mode engines are characterized by partially premixed charge combustion, leading to significant and simultaneous reductions of nitrogen oxides and particulate matter emissions. However, gasoline compression ignition engine operation suffers from a limited operating window. Air preheating and low-research octane number fuels are required to improve the engine performance. This experimental study used a blend of 70% (v/v) gasoline and 30% diesel as test fuel in a direct injection medium-duty compression ignition engine. Experiments were carried out at 5- and 10-bar brake mean effective pressure (BMEP) engine loads at 1500–2500 rpm engine speeds using a triple injection strategy (two pilots and one main injection) for all test conditions. The combustion phasing was kept constant with respect to crank angle to produce a high power output. The investigations examined engine performance and regulated and unregulated emissions. The test engine was initially operated in conventional diesel combustion mode with diesel for baseline data generation. Gasoline compression ignition mode operation demonstrated a remarkable 16% increase in the brake thermal efficiency and a substantial reduction of 65% in nitrogen oxide emissions compared to the baseline conventional diesel combustion mode. The GCI engine exhaust showed higher concentrations of regulated emissions, namely hydrocarbons and carbon monoxide, and unregulated trace emissions, such as methane, acetylene, toluene, inorganic gaseous species, and unsaturated hydrocarbons.

Balancing energy security and marine pollution prevention: legal challenges of utilizing nuclear power for decarbonizing maritime transportation in the Arctic region.

The Arctic region is facing growing demands for energy to support various economic activities, while also grappling with the profound impacts of climate change. Black carbon particulate matter emissions reduction is a key objective to mitigate the susceptibility of the Arctic's ecosystems to the impact of climate change. Nuclear power has been suggested as a potential source of clean energy to decarbonize maritime transport in the Arctic. However, although the operation of nuclear-powered vessels and floating nuclear power platforms in the region ensures energy security and reduces black carbon emissions, it may pose significant risks of nuclear material release and radiological accidents and raise concerns about improper radioactive waste disposal. In regulating these nuclear-powered vessels and floating nuclear power platforms in the Arctic, the existing international legal regime faced a series of challenges. This research employs a method of policy analysis to analyze these legal challenges and explores how the international community could work together to cope with the challenges that arise in the Arctic during the operation of nuclear-powered vessels and platforms for maritime decarbonization purposes.

An experimental study of the performance of a CI engine using ethanol as a fuel stabilizer

Ethanol is a promising alternative fuel owing to its renewable bio-based origin and lower carbon content, as well as its ability to significantly reduce particle emissions in diesel engines. To evaluate the particulate matter emissions and performance of ethanol-diesel blends, researchers conducted experiments using mineral blends of 5% and 10% ethanol with 95% and 90% diesel fuel, respectively, as well as biodiesel blends with 25% biodiesel and 75% diesel fuel, and 100% diesel as a baseline. These blends were tested in a CI engine with a constant RPM of 1350 and variable loads from 0.0 to 1.6 at intervals of 0.2 kg-m. The study found that biodiesel blends reduced exhaust particulate emissions compared to diesel fuel, while the brake specific fuel consumption decreased with increasing brake power, and the brake thermal efficiency increased as brake power increased. The sound pressure level was measured from different locations of the engine, and the results indicated that increasing the percentage of biodiesel led to a decrease in the sound pressure level. Overall, the study concluded that ethanol-blend fuel improved both brake and engine thermal efficiency while reducing particulate matter emissions. The engine experiments evaluated engine brake torque, braking power, brake specific fuel consumption, brake thermal efficiency, and particulate matter emissions under a variable load and a constant engine speed.

An assessment of the application of catalyst preheating prior to engine cold start to improve the filtration performance of CDPF on particulate emissions

The catalytic diesel particulate filter (CDPF) is an effective technology for reducing particle emissions. However, during engine startup, especially in cold start conditions, notable particle emissions are observed at the CDPF outlet. These emissions are attributed to combustion deterioration during startup and the low temperature of the aftertreatment catalyst. Addressing this challenge, this study investigated the effectiveness of rapidly preheating the diesel oxidation catalyst (DOC) and CDPF substrate temperatures before engine start to enhance particle removal during cold starts. Experimental results indicated that CDPF filtration efficiency during cold start was lower compared to hot start conditions, with a clean CDPF exhibiting very low efficiency due to minimal particle deposition. Substrate temperature preheating of either the DOC or CDPF was found to improve CDPF filtration efficiency for particles during cold start, albeit with a concurrent increase in emissions of particles smaller than 50 nm. Notably, a combination of a 250 °C DOC with a 22 °C CDPF yielded the most significant reduction in particle emissions, particularly for particles under 50 nm. Given that the DOC shares the same material composition as the CDPF but has a smaller volume that requires less energy for heating, preheating the DOC emerges as a more energy-efficient strategy. These findings underscore the need for more comprehensive studies on catalyst preheating to further the commercialization of technologies that effectively reduce cold start particle emissions, aligning with increasingly stringent future emission regulations.

Green composite friction materials: A review of a new generation of eco-friendly brake materials for sustainability

Particulate matter (PM) still poses a significant threat leading to air pollution which is responsible for continued damage to human health and the environment. Particulate matter resulting from non-exhaust emissions are considered as viable a source comes mostly from brake pad wear concept. The scientific challenge of this work is to stimulate a new generation of green friction materials to reduce particle emissions having low-environmental impact. The specificity of braking materials, their effects on the environment and human health are studied. To minimize the levels of air pollution, the use of green friction composites collected from natural elements reducing human diseases is discussed. For this purpose, the novel and high-performance friction composite materials synthesized from vegetable and animal waste used as a raw material are reported. The natural powder and fiber treatments, the optimum formulation and the binder materials related to the green friction composites are reviewed. An overview of environmentally ecofriendly green friction materials embedded by reinforcing phases of natural elements exhibiting excellent mechanical and tribological properties are mentioned. Therefore, scientific and industrial efforts should concentrate on the development of green friction materials to minimize the effect of transport related air pollution.

Enhancing Sustainability in Urban Transportation with Innovative Mechanical Engineering Solutions for Electric Buses in Jakarta

This study looks into how novel mechanical engineering solutions for electric bus technology in Jakarta could change the industry, with an emphasis on improving sustainability, efficiency, and performance. Quantitative data was gathered through technical inspections, stakeholder questionnaires, and real-time monitoring. According to the results, buses with regenerative braking systems, lightweight construction, and cutting-edge drivetrain technologies consume 15% less energy. A comparative investigation revealed a 12% boost in overall speed and responsiveness and a 20% improvement in braking efficiency. The environmental benefits were highlighted by the environmental impact evaluations, which showed a notable 25% reduction in particulate matter and emissions. Positive responses to surveys conducted among passengers and bus operators demonstrated the practical viability and user pleasure of these advances. Although they recognized the potential, city officials stressed the need for a thorough and gradual implementation strategy. According to the research, creative mechanical engineering solutions might completely transform Jakarta's urban transportation system and serve as a template for effective and sustainable mobility.

Non-Pharmacological Strategies and Interventions for Effective COVID-19 Control: A Narrative Review.

The COVID-19 pandemic had a devastating impact on the world, causing widespread illness and death. Focusing on prevention strategies to limit the spread of the disease remains essential. Despite the advent of vaccines, maintaining a vigilant approach to prevention remains paramount. We reviewed effective strategies to prevent COVID-19 transmission, including various prevention measures and interventions and both established practices and unresolved issues that have been addressed in meta-analyses, literature reviews, or in the health care context. Standard precautions are the cornerstone of infection control, with hand hygiene and mask use as key components. The use of surgical masks is recommended to prevent droplet transmission, while eye protection is recommended in combination with masks. In terms of room occupancy, ventilation is critical in reducing the risk of transmission in poorly ventilated environments. Chemical disinfection of indoor air with Triethylene glycol-based products can provide safe additional protection. Since viral RNA detection on surfaces does not necessarily indicate infectivity, the risk of transmission by surface contact remains low if surfaces are properly maintained and hand hygiene is practiced regularly. Thus, prevention of SARS-CoV-2 transmission requires a multifaceted approach, including reducing particle emissions from infected persons by wearing masks, eliminating aerosols by ventilation and air treatment, ensuring physical separation, and protecting exposed persons with masks and eye protection.

Development of emission reduction measures of particulate matter emitted from coal fired power plants in Indonesia

Currently, Indonesia has committed to achieve Net Zero Emissions (NZE) efforts on their Nationally Determined Contribution (NDCs) and at the same time focusing on air pollution abatement. One of the dominant emissions sources of particulate matter as well as Greenhouse Gases (GHGs) is from coal fired power plants. It contributes 50% to the total energy consumption in power generation, therefore the major power plant in Indonesia. Therefore, efforts to reduce GHGs and particulate emissions are needed to achieve the NZE target as well as to improve air quality. The research objective is to determine the particulate pollution load based on the Business as Usual (BaU) scenario and also under the emission reduction scenario for the year of 2030. Particulate pollution load was calculated using the emissions inventory methodology described in the brown cloud atmosphere workbook (ABC-EIM). Particulate emission reduction scenarios were developed using the assumption of full installation of Electrostatic Precipitator (ESP) technology to control PM emission. In 2030, the emission reductions PM10, PM2.5, Black Carbon (BC), and Organic Carbon (OC) are 57,854 ton/year, 57,854 ton/year, 432 ton/year, and 1,723 ton/year.

Reducing particulate emissions by using advanced engine oil nanoadditives based on molybdenum disulfide and carbon nanotubes

Nanoadditives can be used to enhance lubricating properties of engine oils. Although many additives have been developed, molybdenum disulfide and carbon nanotubes have attracted significant attention. In this study, we demonstrate that hybrid nanostructures based on these unique materials (MoS2/CNTs) positively affect engine oil lubricating properties. Hybrid nanostructures were produced via wet chemical synthesis in impinging jet reactor. This method is characterized by easy scalability and possible continuous operation, which are crucial in material commercialization. The application of 0.5 wt% suspension exhibited the best results, reducing the friction coefficient at the engine operating temperature by up to 26%. Nanoadditives protected the lubricated parts, causing their wear to be considerably lower than the base oil. The effect of nanoadditives on the quality of exhaust gases was also investigated, which has not yet been researched. The application of the oil with MoS2/CNT reduced the emissions of solid particles in the gasoline engine exhaust gas. The total volume of particles in the exhaust gas was reduced by 91% and 49% under idling and load-running conditions. This research showed that MoS2/CNTs can be successfully used as nanoadditives in engine oils for improving tribological properties, enhancing anti-wear performance, and reducing particle emissions in exhaust gas.

Experimental study on gas and particle emission characteristics of carbon black oxidation process in the presence of water and catalysts

The study of oxidation characteristics of carbon black particle is the basis to investigate the regeneration process and characteristics of diesel particulate filter (DPF). Based on the fixed-bed test bench, the gas and particle emission characteristics of carbon black oxidation process in the presence of water are investigated under different temperatures, Printex-U (PU) masses, and catalysts. The experimental results show that the rise of temperature and PU mass increases the emissions of CO, CO2 and the total average particle number (PN). The oxidation efficiency (η) increases with temperature, but decreases with PU mass. The addition of catalysts promotes PU oxidation, and reduces CO emission. Due to the influence of particle diffusion, CeO2 has slightly lower efficiency than Pt/Al2O3 in the same ratio (1:1), but it is beneficial to significantly reduce particle emission, especially as the ratio increases (1:5). Water decreases CO and the η in PU oxidation, and the negative impact is gradually reduced after 3 % water concentration; However, the PN significantly increases, and expands the particle size range, particularly at high temperature and adding Pt/Al2O3 (from about 10 nm to 6– 30 nm, and a large number of particles with 30– 100 nm are produced). Additionally, the CO2/CO ratio of carbon black oxidation gradually increases with water concentration. Controlling DPF regeneration needs to strike a balance between the benefits on increasing oxidation efficiency and the potential negatives on particulate and harmful gas emission.

Present and future emission characteristics of air pollutants and CO2 from the Beijing transport sector and their synergistic emission reduction benefits

Coordinated control of both carbon dioxide (CO2) and air pollutants from the urban transport sector will deliver the greatest benefit to climate and health. To calculate and assess the synergistic control effect on CO2 and air pollutants from various transport types in Beijing from 2021 to 2050, we built a quantitative analysis model based on the Long-range Energy Alternatives Planning framework. Results showed that passenger transport was the dominant contributor to CO2 and major air pollutants (fine particles, carbon monoxide, volatile organic compounds) emitted from the transport sector in 2021 in Beijing. An exception is for nitric oxide which was mostly from freight transport. Clean energy alternatives for road vehicles and aviation, and electrification of railways offer the best synergistic emission reduction potential for both CO2 and air pollutants, and are also the most important measure to realize carbon neutrality in transportation. A change in transport mode (e.g. from road to rail) and the early elimination of aging vehicles would lead to a greater synergistic effect than that achieved by improving fuel economy in the short-term, except for co-benefits for fine particles and CO2 for which the fine particle emission reduction was much lower than that of CO2. In general, the adoption of clean energy for motor vehicles and aviation (e.g., electric vehicles, hydrogen fuel cell vehicles, and bio-fuels), is the best way for Beijing to quickly pass the carbon peak and achieve neutrality in the transport sector and improve air quality in the future.

Characterization of in-cylinder spatiotemporal flame and solid particle emissions for ethanol-gasoline blended in gasoline direct injection engines

Stricter regulations for internal combustion engines have necessitated the inclusion of eco-friendly fuels with conventional ones to reduce gas and solid emissions. Gasoline direct injection (GDI) engines, however, have been found to produce more particle number and mass emissions than port fuel injection engines. To address this, bioethanol fuel has been selected as an additive eco-friendly fuel for gasoline, with the aim of reducing particle emissions. In this study, we quantitatively characterize in-cylinder spatiotemporal flame to feature combustion performance and particle emissions for ethanol fuel in the GDI combustion chamber. We examined three engine combustion modes differed in equivalence ratio and injection strategy to produce various combustion results to quantify combustion performance and particle emission characteristics. Using an eight-channel non-intrusive flame luminosity sensor in one cylinder, we measured the flame front and its propagation direction. At the tailpipe, we measured particulate emissions using an engine exhaust particle sizer and a micro soot sensor coupled with a catalytic stripper that removed semi-volatile compounds. Our study found that increasing ethanol fuel content for different combustion modes resulted in distinct combustion and flame development. The particle size distribution also showed different patterns at each combustion mode, depending on the ethanol content. Lean combustion modes yielded high diffusion flame intensity compared to stoichiometric combustion mode, which resulted in a larger amount of particle formation. The physical properties of ethanol fuel were found to predominantly determine the fuel-air mixture quality, combustion process, and flame development at each combustion mode. An increase in ethanol fuel content at lean-homogeneous mode resulted in higher diffusion flame intensity and larger particle emissions. Our comparative study of flame and solid particles for ethanol fuel content improves the understanding of in-cylinder combustion processes and their correlations.