Regular Gasoline Research Articles

A methodology to replicate LTGC engine conditions in a single-zone model and validate gasoline surrogate formulations versus experimental measurements

In this work, surrogate fuels for three premium-grade gasoline fuels were formulated and its autoignition behavior was validated, together with that of an existing surrogate for E10 regular gasoline, by comparison to experimental data measured in the Sandia Low-Temperature Gasoline Combustion research engine facility. Surrogate fuels have been previously designed by matching fuel properties such as octane number, fuel/air stoichiometric ratio and hydrogen/carbon ratio. However, similar octane rating can be obtained with several blends that will show different ignition characteristics. To avoid this issue, the surrogate fuels shown in this paper have been formulated by matching the main components of the fuel detailed hydrocarbon analysis. Validation of the surrogates was performed by replicating engine experiments run with the real fuel in a 0-D internal combustion engine reactor model with detailed chemistry. A fitted heat-loss model had to be implemented to properly replicate the experimental in-cylinder thermodynamic conditions, which invalidates the adiabatic assumption sometimes applied to engine simulations. Furthermore, minor species present in the EGR and residuals, such as CO and NOx, had to be taken into account to replicate the experimental low-temperature heat release (LTHR) trends. Therefore, accounting for heat losses and detailed in-cylinder composition are essential to accurately simulate the engine data. The bottom dead center temperature deviation required to obtain the same combustion timing as in the experiments was used as a metric to evaluate the accuracy of simulations. The surrogates gave good performance for the whole explored range, and replication of LTHR is a key factor in matching the experimental data. Chemical kinetic analyses showed that replication of LTHR is controlled by the ability of the surrogate to properly balance radical generation from low-temperature chain branching decomposition with radical consumption from stable species. Surrogate components that act as a sink of radicals tend to suppress the LTHR of the fuel, which may lead to large deviations between simulations and experiments. Especial attention should be paid to these fuel species when selecting the surrogate components.

Engine Performance and Emission Evaluation of Gasoline-Ethanol Fuel Blend in SI Engines Under Various Conditions of Load and Speed

Ethanol fuel is considered a renewable energy source with a lower global warming potential than gasoline. The purpose of this paper is to analyze the emissions and performance of gasoline-ethanol blends in SI engines under various conditions. A computerized 4s, 1cyl, VCR spark ignition engine is used for the tests to measure the performance of Gasoline-Ethanol (GE) blends in particular E-10 (10% ethanol, 90% gasoline). For measuring exhaust emissions as well as performance, regular gasoline fuel is used for the additional tests. Engine performance using ethanol-gasoline blended fuel has been evaluated at different working conditions: 1200–1800 rpm, AFR 0.9, STs 300, CR10:1. When vehicles running on ethanol-gasoline blend indicated a decrease in the amounts of HC, NOx, and CO exhaust gases while 3.9% increase in CO2 emissions as compared to unleaded gasoline fuel. Furthermore, it has been shown that the brake power, torque, specific fuel consumption increases when a Gasoline-Ethanol (GE) blend is used over regular gasoline fuel.

Application of Cluster Analysis in the Evaluation of Automotive Fuel Prices Marketed in Goiás

Objective: The aim of this study is to present economic indicators constructed through cluster analysis, aiming to identify which gas station brands offer the lowest overall fuel prices. Theoretical Framework: The increasing demand for low-cost products, particularly automotive fuels, is a constant in the Brazilian market, significantly impacting both the economy and consumers' daily lives. This scenario underscores the analysis of prices as a crucial tool for understanding market behavior. Method: Data were obtained from the open data portal of the National Agency of Petroleum, Natural Gas and Biofuels (ANP), focusing on the historical price series of regular gasoline, premium gasoline, and ethanol in the state of Goiás. Cluster analysis was employed to group eight gas station brands into three distinct clusters. Results and Discussion: Findings reveal that Rodoil offers the lowest overall fuel prices, whereas Alesat, Ciapetro, and Raízen have the highest overall prices. These discoveries provide valuable insights into the competitive dynamics of the fuel market in Goiás. Research Implications: The significant debates generated in society by the rising prices of gasoline, ethanol, and other products such as cooking gas and diesel underscore the urgent need to revise fuel pricing policies in the country. Originality/Value: This study contributes uniquely by applying cluster analysis to identify price patterns among different gas station brands, offering an innovative approach to understanding competitiveness in the fuel distribution sector in Goiás.

Average Carbon Number Analysis and Relationship with Octane Number and PIONA Analysis of Premium and Regular Gasoline Expended in Ecuador

The quality of fuel depends on its chemical composition, which influences engine performance. Gas chromatography, a cornerstone of global oil and fuel R&D, remains crucial for ensuring the quality of petroleum products and regulatory compliance. Scientists use the most accurate analysis (PIONA) as a tool derived from gas chromatography coupled with mass spectrometry to identify and quantify hydrocarbons that influence resistance to detonation, which is determined by the research octane number (RON). This study introduces the “average carbon number (ACN)”, calculated from the molar chemical composition of commercial gasoline samples sold in Ecuador (Extra gasoline and Súper gasoline). A quantitative comparison of the ACN with techniques applied using standardized international procedures reveals that the ACN characterizes gasoline samples by providing insight into the distribution shape of carbon graphs. A comprehensive statistical analysis demonstrates the potential usefulness of ACN in characterizing fuel composition, highlighting its relevance in broader fuel quality assessments without the need for carbon distribution plots.

Source differentiation of BTEX compounds in groundwater contaminated due to refinery activities

This study aims to identify sources of groundwater contamination in a refinery area using integrated compound-specific stable isotope analysis (CSIA), oil fingerprinting techniques, hydrogeological data, and distillation analysis. The investigations focused on determination of the origin of benzene, toluene, ethylbenzene, and xylenes (BTEX), and aliphatic hydrocarbons as well. Groundwater and floating oil samples were collected from extraction wells for analysis. Results indicate presence of active leaks in both the northern and southern zones. In the northern zone, toluene was found to primarily originate from oil products like aviation turbine kerosene (ATK or aviation fuel), kerosene, regular gasoline, and diesel fuel. Additionally, stable isotope ratios of carbon and hydrogen for ethylbenzene, o-xylene (ortho xylene) and p-xylene (para xylene) in zone A suggested the pollution originated from gasoline within the northern zone. The origin of super gasoline (with higher octane) identified in southern zone using δ13C and δ2H values of toluene in the floating oil and groundwater samples. Further, biodegradation of toluene likely occurred in southern zone according to δ13C and δ2H. The findings underscore the critical importance of integrating CSIA and fingerprinting techniques to effectively address the challenges of source identification and relying solely on each method independently is insufficient. Accordingly, comparing the GC-MS results of floating oil samples with ATK and jet fuel (JP4) standards can be effectively utilized for source differentiation. However, this method showed no practical application to distinguish different types of diesel or gasoline. The accuracy and reliability of source identification of BTEX compounds may significantly improve when hydrogeological data incorporates with stable isotopes analysis. Additionally, the results of this study will elevate the procedures for fuel-related contaminants source identification of the polluted groundwater that is crucial to develop effective remediation strategies.

Experimental Research on Regulated and Unregulated Emissions from E20-Fuelled Vehicles and Hybrid Electric Vehicles

Ethanol as a renewable fuel has been applied in fuel vehicles (FVs), and it is promising in hybrid electric vehicles (HEVs). This work aims to investigate the emission characteristics of ethanol applied in both FVs and plug-in hybrid electric vehicles (PHEVs). The paper conducted a real-road test of an internal combustion FV and PHEV, respectively, based on the world light vehicle test cycle (WLTC) by using gasoline and regular gasoline under different temperature conditions. The use of E10 and E20 in FVs has been effective in reducing the conventional emissions of the vehicles. At 23 °C, E10 and E20 reduced the conventional emissions including carbon monoxide (CO), total hydrocarbon compound (THC), non-methane hydrocarbon compound (NMHC), particulate matter (PM), and particulate number (PN) by 15.40–31.11% and 11.00–44.13% respectively. At 6 °C, E10 and E20 reduced conventional emissions including THC, CO, and PM by 2.15–8.61% and 11.02–13.34%, respectively. However, nitrogen oxide (NOX) emissions increased to varying degrees. The reduction trend of non-conventional emissions including methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) from FVs fueled with E10 and E20 is not significant for vehicles. Overall, the emission reduction effect of E20 is better than that of E10, and the emission reduction effect of ethanol gasoline on vehicle emissions is reduced at low temperatures. Lower ambient temperatures increase vehicle emissions in the low-speed segment but decrease vehicle emissions in the ultra-high-speed segment. HEV emissions of THC, CO, PN, and PM are reduced by 25.28%, 12.72%, 77.34%, and 64.59%, respectively, for E20 compared to gasoline, and the use of E20 in HEVs contributes to the reduction of overall vehicle emissions.

Practical low-temperature gasoline combustion for very high efficiency off-road, medium- and heavy-duty engines

Low-temperature gasoline combustion (LTGC) with additive-mixing fuel injection (AMFI) is a new combustion strategy that has been demonstrated to deliver 9%–25% better brake thermal efficiency than similar-sized market-leading diesel engines over the operating map. Moreover, the LTGC-AMFI engine shows near-zero smoke, and NOx emissions are 4–100 times lower than those of a diesel, sufficiently low that no aftertreatment, or only passive NOx aftertreatment, would be sufficient (diesel exhaust fluid is not required). LTGC-AMFI combustion is based on kinetically controlled compression ignition of a dilute charge with a variable amount of low-to-moderate fuel stratification. Fast combustion control is provided by adding minute amounts of an ignition-enhancing additive into the fuel each engine cycle to control its reactivity. This strategy was used to operate a medium-duty (MD) LTGC-AMFI engine at loads from idle to 16.3 bar BMEP and speeds from 600 to 2400 rpm with regular E10 gasoline, which covers nearly the entire operating map of a typical MD engine. Turbine-out temperatures were sufficient for an oxidation catalyst to control hydrocarbon and CO emissions. Autonomie simulations over the GEM ARB Transient and the GEM 55 mph Cruise driving cycles for class-6 trucks using this technology showed fuel economies of 8.1 and 11.4 mpg-gasoline-equivalent, respectively, corresponding to 18.6% and 13.4% improvements over a similar-size diesel engine. Engine-out NOx emissions were 0.024 and 0.01 g/bhp-h, respectively, well below current U.S. emission standards. These results show that switching from diesel to LTGC-AMFI engines would greatly reduce greenhouse gas (GHG) emissions for off-road, MD and HD applications, which will continue to rely on combustion engines because electrification is not practical in the foreseeable future. With their reduced fuel consumption, the lower cost of gasoline compared to diesel fuel, and much lower aftertreatment costs, LTGC-AMFI engines also offer a significantly lower total cost of ownership.

Qualitative assessment of regular and premium gasoline available in Bangladesh markets

Assessing the quality of fuel is essential to comprehend its impact on the environment and human health. In this study, the evaluation of fuel quality standards at the consumer level was conducted by analyzing the motor fuels in Khulna, Bangladesh. A total of 32 samples of petrol (regular gasoline), and octane (premium gasoline) were collected from the fuel stations in the Khulna City Corporation area and analyzed with an FTIR-Fuel Analyzer. Fuel properties, such as research octane number (RON), motor octane number (MON), ethanol content, olefins content, and oxygen content were analyzed. For petrol, the average RON, MON, olefins, and oxygen content were 95.34, 85.70, 8.23 %v/v, and 0.78 %m/m, respectively, and for octane, they were 96.96, 85.39, 1.25 %v/v, and 0.09 %m/m, respectively. Almost all of these parameters complied with both Bangladesh standard and Euro 5 fuel specifications, and those that did not comply were very close to their standard values. However, benzene concentration, which was not specified in Bangladesh Standard, was the most alarming metric for octane since none of the samples matched the Euro 5 fuel specifications of the maximum concentration of 1 %v/v benzene; on average it was 3.70 %v/v. Although petrol benzene content (average 1.50 %v/v) was not as bad as it was for octane, it was still nowhere near good enough, with only 25% of the samples within the recommended level among the studied sample. This information holds significance in establishing the fuel profile and facilitating the identification of distinct samples linked to adulteration. Therefore, the analysis of motor fuel qualities is essential for maintaining the environment, human health, and the economy of a country.

Impacts of ethanol blended fuels and cold temperature on VOC emissions from gasoline vehicles in China

The Chinese central government has initiated pilot projects to promote the adoption of gasoline containing 10%v ethanol (E10). Vehicle emissions using ethanol blended fuels require investigation to estimate the environmental impacts of the initiative. Five fuel formulations were created using two blending methods (splash blending and match blending) to evaluate the impacts of formulations on speciated volatile organic compounds (VOCs) from exhaust emissions. Seven in-use vehicles covering China 4 to China 6 emission standards were recruited. Vehicle tests were conducted using the Worldwide Harmonized Test Cycle (WLTC) in a temperature-controlled chamber at 23 °C and −7 °C. Splash blended E10 fuels led to significant reductions in VOC emissions by 12%–75%. E10 fuels had a better performance of reducing VOC emissions in older model vehicles than in newer model vehicles. These results suggested that E10 fuel could be an option to mitigate the VOC emissions. Although replacing methyl tert-butyl ether (MTBE) with ethanol in regular gasoline had no significant effects on VOC emissions, the replacement led to lower aromatic emissions by 40%–60%. Alkanes and aromatics dominated approximately 90% of VOC emissions for all vehicle-fuel combinations. Cold temperature increased VOC emissions significantly, by 3–26 folds for all vehicle/fuel combinations at −7 °C. Aromatic emissions were increased by cold temperature, from 2 to 26 mg/km at 23 °C to 33–238 mg/km at −7 °C. OVOC emissions were not significantly affected by E10 fuel or cold temperature. The ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) of splash blended E10 fuels decreased by up to 76% and 81%, respectively, compared with those of E0 fuels. The results are useful to update VOC emission profiles of Chinese vehicles using ethanol blended gasoline and under low-temperature conditions.

A STUDY OF THE RELATIONSHIP BETWEEN THE OCTANE NUMBER AND THE CHEMICAL COMPOSITION OF REGULAR, MIDGRADE, AND PREMIUM GASOLINE

The present study was conducted at Zakho City in Northern Iraq to evaluate three different types of gasoline: Regular, Midgrade, and Premium. These types of gasoline are categorized based on their octane rating, which was measured to verify their classification. The results showed that the initial classification was accurate, with respective values of 87.5, 89.8, and 91.1. The study evaluated the three grades of gasoline available at Zakho Gas Stations in Northern Iraq, including Regular, Midgrade, and Premium. The study also compared the chemical composition of the three gasoline grades in terms of aromatics, olefin, sulfur content, and oxygen content. All the three gasoline grades met the American Society for Testing and Materials (ASTM) standard for chemical composition, and all had acceptable specific gravities. However, Midgrade gasoline is not recommended for use during the summer due to its high Reid vapor pressure (RVP) value, low Initial boiling point (IBP), and final boiling point( FBP). In general, the study showed that the Regular and Premium gasoline types sold in North of Iraq meet international quality standards. However, Midgrade gasoline is not recommended for use during the summer due to its high RVP value, low IBP, and FBP, which can lead to increased volatility and environmental pollution, Moreover, using this type of gasoline may cause problems with the car engine.

Enfoque químico “estructura-conformación” de la gasolina regular en el mercado de combustibles ecuatoriano

A source of chemical energy storage is fossil fuels that in Ecuador are represented by two derivatives: regular gasoline -EcoPlus- (89 octanes), premium -EcoPremium- (96 octanes), and diesel. This shows that the market is not only focused on automobiles but also on agricultural and industrial machinery. There is currently a remission of the sale price to the public as there are subsidies from the Ecuadorian government. Regular 89-octane gasoline is the most widely used for the abovementioned purposes and for implementing and adapting new proposals in modifying 4-stroke engines. This gasoline mixture's composition and octane isomers were analyzed for physicochemical properties related to its liquid state and intermolecular interactions concerning variables such as boiling points and volatility. With the three-dimensional conformation obtained, it was possible to correlate the variables, as mentioned earlier, with the stabilized structures in the gasoline mixtures.

Experimental Analysis of Gasoline-Ethanol-Methanol Blend at Various Conditions in Engine

Renewable resources are minimal throughout the world and considerable research work has been carried out to develop fossil-based options. Aim of the research work is to evaluate performance and engine exhaust emissions of varying blends at different conditions in engine. The experiments are conducted to analyze the performance of three distinct gasoline-alcohol fuel mixtures EM25 (10 percent ethanol-15 percent methanol-75 percent gasoline) in a computerized 1-cylinder, 4-stroke, VCR SI engine. The additional tests are conducted using regular gasoline fuel to compare performance and engine exhaust emissions. The engine performance using mixed fuel of ethanol-methanol-gasoline (GEM) has been evaluated under the various operating conditions in the range of 1200 to 1800 rpm, Spark Timings (ST’s) 100, Air Fuel Ratio 0.9 at constant Compression Ratio (CR) 10:1. When the vehicles operated with ethanol-methanol- gasoline mixtures then it has found that there is the reduction in HC, CO2, CO exhaust gases contents while 14% increments in NOx emission as compared with regular gasoline fuel. It is also observed that the brake power/brake torque is decreased when operated on ethanol-methanol-gasoline fuels as compared to pure gasoline. However, it has been revealed that BSFC is enhanced in comparison to regular gasoline.

A review on the performance of non-additive blended fuel (ethanol-gasoline) in spark ignition engines

The use of effective fuel additives can improve fuel and engine efficiency, but some non-additive or incompatible additives can cause engine problems. Ethanol-gasoline blends offer advantages as an alternative to regular gasoline, but high-dose blends with non-additives can lead to issues such as deposits in the engine, increased combustion temperature, emissions, and power loss. This paper reviews various fuel additives and their impacts on engine performance. Early anti-knock additive based on organometallic compounds were used in the past but faced concerns regarding cost, legislation, health effects, and environment. Ethanol and other oxygenated additives have been used to increase research octane numbers, improve combustion and fuel economy. While ethanol has benefits of improved efficiency and reduced emissions, it is not considered an additive. Therefore, finding a chemical additive that enhances fuel efficiency, combustion, and reduces greenhouse gas emissions is crucial. This research aims to explore and provide solution in this area.

Evaluation of the Performance Curves of the 4-Stroke, Spark-Ignited, Single-Cylinder Engine Altered to Consume Ethanol

Objective: To conduct tests on the B4T-5.5 hp spark-ignition engines (Otto cycle) with conventional fuels (types of gasoline) and, after modification, to test with renewable fuels (Ethanol) on the dynamometer in the engineering laboratory of Branco Motores Ltda., following SAE J1995 and SAE J1940 standards. Analyze the power and torque curves for each tested fuel. Theoretical framework: Utilizing the literature through research in books, dissertations, articles, and standards. Method: This study involves the performance of a gasoline engine converted to ethanol (renewable fuel) through quantitative research and the evaluation of test results on the 5.5 hp single-cylinder 4-stroke spark-ignition engine (B4T model) with each proposed fuel in the research. Results and Conclusion: During the analysis, the necessary values were measured to create the power and torque curves using different types of national fuels. The spark-ignition engine was connected to a dynamometer and tested with regular gasoline (Type C with 27.5% ethanol content), premium gasoline, podium® gasoline, and anhydrous ethanol 95% (the gasoline engine was modified to operate with ethanol). In the case of the renewable fuel, ethanol, the results for the spark-ignition engine (Otto cycle) showed an increase of 0.48 hp in power and 0.11 kgf.m in torque compared to gasoline. The ethanol-powered engine is a viable alternative and is considered a clean energy source when compared to traditional fuels (such as gasoline). Research Implications: Issues such as sustainability, renewable energies, environmentally friendly fuels, greenhouse gas emissions, and concerns about the environment have become increasingly common and evident in the global market. This reflects a global concern for environmental preservation and the future of the planet. For academia, the constant search for new or alternative sources will always be a challenge. Originality/Value: The proposal of an ethanol engine contributes to the reduction of pollutant gas emissions and environmental damage because ethanol, derived from sugarcane, absorbs carbon monoxide and carbon dioxide during the plant's development. This attenuates emissions since, during the ethanol burning process, the gases are only returned to the atmosphere (carbon and derivatives), unlike the burning of fossil fuels, which adds more gases to the atmosphere. Another point is that it provides an additional option for end consumers.

Characteristics of gasoline flash boiling atomization triggered by iso-pentane blends at different ratio

Flash boiling spray can improve fuel atomization efficiency via fierce phase change of the fuels both inside and outside the nozzle. Typically, active flash boiling atomization is achieved by heating the fuel before injection, which would require additional energy for heating and more complex fuel temperature controls. Another approach to enable flash boiling atomization is to dope fuels with low boiling points into regular fuels. However, the atomization and combustion mechanisms of adding low boiling point fuels are not fully revealed yet. This investigation aims to study the effect of mixing a low boiling point fuel (iso-pentane) with regular gasoline fuels. The fuel temperature is controlled so that flash boiling of iso-pentane is triggered while gasoline is still under its sub-cooled conditions. The iso-pentane volume fractions of 0%, 40%, and 80% bent with RON 95 gasoline were tested in this study. Microscopic analysis was made to understand the near-field breakup characteristics using different fuel combinations. It is found that the blends of iso-pentane could significantly enhance the atomization process due to a combination effect of flash boiling and evaporation, while flash boiling tends to extend the spray width, resulting in better fuel-air mixing and a more homogenous mixture.

Quantum dots luminescent compounds with multimodal luminescence for fuel labeling

The article considers the possibility of labelling oil products using luminescent ‘fingerprints’ based on several types of quantum dots to protect fuel from falsification. For the synthesis of quantum dots, a scalable universal method was proposed using an available large-producible solvent and a stabilizer, oleic acid. Using the developed technique, quantum dots were obtained that luminescence in the entire visible range of the electromagnetic radiation spectrum. The formation of nanoparticles was confirmed by a set of instrumental research methods. The determination of the presence of quantum dots in the composition of an oil product was proposed using spectrofluorometry with no additional separation or dialization of nanoparticles from the sample. Using normal regular gasoline as an example, the effect of fuel on the luminescence of quantum dots and their aggregation was studied. The interaction of different types of quantum dots in the composition of the indicator and their influence on each other’s luminescence in solvent and gasoline were analyzed. The minimum detectable by the spectrofluorometric method concentrations of quantum dots in normal gasoline and the optimal proportions of quantum dots of various types in mixtures were determined.

Asymmetric Price Transmission between Crude Oil and the US Gasoline Market

Gasoline and crude oil price movements have been the focus of many studies in the last decade. We use the asymmetric error correction model (ERM) to examine the hypothesis of asymmetric pricing for both regular and premium gasoline markets at the US national level and in the four states with the highest gasoline consumption. Using weekly crude oil and retail gasoline prices from June 2000 to February 2023, the results show an asymmetric response in the gasoline market for all four states and at the national level. However, the adjustment speed tends to differ for the types of gasoline and across states. The implications of these results for policy and welfare are discussed in this study.

Quality-Cost Analysis of Gasoline Production Process

Process capability provides a quantitative measure for gasoline production conformance to specifications.It was measured throughout four consecutive months of the last quarter of 2011. Results revealed high percentages (up to 44%) of non conforming gasoline blends to Iraqi marketing specifications for petroleum products (2000) by inspecting 122 different samples of Iraqi regular gasoline (RON 85).Quality cost analysis as an important financial control tool was carried out to evaluate Cost of Quality (COQ) which was large due to non conforming gasoline reached up to (722.8 M.ID) in October. In this research COQ was investigated in order to identify the opportunities of gasoline quality improvements through production process. Also customers’ direct cost loss due to poor gasoline quality was verified and calculated, where amounted to its highest value (9.084960 M.ID) at November.

Spray dynamics of synthetic dimethyl carbonate and its blends with gasoline

Synthetic dimethyl carbonate (DMC) is a promising alternative or oxygenated additive fuel to reduce not only CO2 but also particle number (PN) emissions from gasoline direct injection (GDI) engines. Despite many investigations on the engine performance of DMC-gasoline blends in the literature, limited reports can be found focusing on their spray characteristics. However, a comprehensive understanding of spray characteristics is crucial to interpret the results of GDI engine tests. Therefore, this study was to examine the near-nozzle spray dynamics of the DMC-gasoline blends by using the X-ray phase contrast imaging technique. First, the fuel properties of the synthetic DMC and regular gasoline blends were quantified. Then, the near-nozzle spray dynamics were examined in both non-evaporating and evaporating conditions, and discussions were made accordingly to link the near-nozzle spray dynamics with fuel properties. It is found that increasing DMC content could enlarge the spray spreading angle and reduce the near-nozzle spray velocity by up to +22 % and –18 %, respectively. The near-nozzle-exit spray velocity depends sharply on the fuel density as the DMC content varies in the blends. However, this dependency gradually becomes insignificant as the spray propagating distance increases. Pure DMC has the largest Sauter mean diameter (SMD) and least droplet number than other blends, but they tend to be consistent as the ambient gas temperature increases. The existing empirical correlation is still feasible to predict the SMD of the DMC-gasoline blends, but certain tuning of the constants is necessary. Within the experimental conditions in this study, the DMC-gasoline blends should undergo the same spray breakup regime, i.e., the atomization regime.

ESTUDO DE GASOLINAS PREMIUM E COMUM COMERCIALIZADAS NO BRASIL ATRAVÉS DO MÉTODO ERETIC-RMN E QUIMIOMETRIA

STUDY OF PREMIUM AND REGULAR GASOLINES MARKETED IN BRAZIL THROUGH THE ERETIC-NMR METHOD AND CHEMOMETRICS. Gasoline is a complex mixture of hydrocarbons whose detailed study of its chemical profiles is a challenging task. This type of product of great commercial importance has its quality measured in Brazil from classical physicalchemical tests. Although robust, physical-chemical analyses generally require large amounts of assays, solvents, and samples, in addition to not being indicated for the detection of small compositional changes. In this work, NMR and chemometrics were used in the quantitative study of different samples of gasoline with varying ratings of octane and ethanol contents. The results demonstrated the usefulness of NMR spectroscopy both to characterize as well as to distinguish the chemical profiles of regular and premium gasoline. With the application of the ERETIC, the chemical profiles mentioned were quantitatively differentiated and the proportions between hydrocarbons were determined for both types of gasoline. The application of the ERETIC was also successful in the quantitative determination of ethanol contents in regular and premium gasoline. The aforementioned method, which dispenses with the use of quantification standards inserted directly into the sample of interest, was unequivocal in accounting for the volume of ethanol, in addition to showing excellent agreement with the method currently adopted by the Brazilian government.