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The results of diagnostic tests under steady-state speed conditions of an unloaded engine do not fully reflect the emissivity of vehicles adapted to run on natural gas. Therefore, it is reasonable to pay attention to the emissions performance of these vehicles under dynamic conditions. In this regard, the tests were carried out on a chassis dynamometer with the engine fueled by gasoline and natural gas. Due to the area of operation of natural gas vehicles being usually limited to urban areas, the urban phases of the NEDC (New European Driving Cycle) and WLTC (Worldwide harmonized Light-duty vehicles Test Cycle) were adapted. While CO2 emissions are lower when fueled by natural gas, CH4 emissions can be high, which is related to momentary changes in the composition of the combustible mixture. Although CH4 emissions are higher when the engine runs on natural gas, the CO2eq value is, depending on the driving cycle, about 15–25% lower than when running on petrol. Additionally, studies have shown that in engines adapted to run on CNG (compressed natural gas), it is advisable to consider the use of catalytic converters optimized to run on natural gas, as is the case with vehicles which are factory–adapted to run on CNG. [ABSTRACT FROM AUTHOR]

Differences between the results obtained in laboratory and road tests of vehicles depend on a number of factors. Among the most important of these are driving cycle and road load. These parameters also affect the hybrid drive control, including the combustion engine operation or driving in electric mode. In most studies, tests carried out on chassis dynamometers concern type approval cycles (NEDC—New European Driving Cycle, WLTC—World-wide harmonized Light duty Test Cycle, FTP— Federal Test Procedure), which differ from real on-road tests. Consequently, the different driving cycles do not allow for results similar to those obtained during on-road driving, especially as the actual cycles on the road are unrepeatable. It is also important to determine the effect of the motion resistance function adopted for chassis dynamometer tests on exhaust emissions and fuel consumption. For this purpose, the authors tested a hybrid car under road and laboratory conditions for the same driving cycle. The analysis was conducted for an example urban road cycle in Rzeszow (URRC). The purpose of the study was to determine the differences in the results of gaseous emissions (THC, CO, CO2, NOx) and fuel consumption (energy) of a hybrid car under road conditions, with the results of tests conducted on a chassis dynamometer, for the same cycle and three functions of resistance. [ABSTRACT FROM AUTHOR]

Electric cars, like internal combustion vehicles, emit particulate pollution from non-exhaust systems, i.e., tires and brakes, which is included in the Euro 7 emission standard planned for implementation. Tests conducted on chassis dynamometers are accompanied by particulate emissions from non-exhaust systems, which are introduced into the ambient air on the test bench. Particulate emissions tests from non-engine systems on chassis dynamometers are mainly aimed at measuring the mass or number of particulates from tires and brakes. In contrast, little attention is paid to the immission of particulate matter from tires and brakes on the dynamometer during tests, which in the case of electric cars include, for example, measurements of energy consumption or range. Therefore, in order to draw attention to the problem of these emissions, the authors carried out measurements of PM2.5 and PM10 immissions into the air in the climatic chamber during tests of an electric car on a chassis dynamometer. The car tests were carried out in accordance with the WLTC (Worldwide harmonized Light duty Test Cycle) and at constant speed. Based on the test results, a model was proposed for the immission of particulate matter in laboratory air from tire and brake abrasion, taking traffic parameters into account. The results and the developed model show that air quality, in terms of particulate content, deteriorates significantly during testing. [ABSTRACT FROM AUTHOR]

• CVCC method was used in the investigation. • Derived cetane numbers for RME and 1-butanol were determined. • Ignition and combustion delay for 1-butanol–biodiesel blends were measured. • Tests of auto-ignition were realized for different combustion chamber temperatures. In this article, the auto-ignition properties of blends of high cetane rape methyl esters (RME) as biodiesel and 1-butanol were investigated, with 1-butanol fractions of up to 25% by volume. The tests were performed using the constant volume combustion chamber (CVCC) method to determine the combustion chamber temperature effect (between 550 °C and 650 °C) on the ignition delay (ID) and combustion delay (CD) periods of the verified blends. The research of the auto-ignition properties was complemented with the derived cetane number (DCN) and the calorific properties of the fuels tested. The results uncovered several properties relating to such blends and also showed that the periods of ID and CD increase with an increase in the 1-butanol fraction in the 1-butanol–biodiesel fuel blend (1-BBF). The work also shows that an increase in the temperature of the combustion chamber into which the fuel is supplied causes delay periods to shorten to varying degrees. For fractions of 5–25% by volume in 1-butanol, for each addition of a 5% fraction of 1-butanol, the cetane number for 1-BBF decreases by an average of 4.2 units. [ABSTRACT FROM AUTHOR]

Highlights • Ignition and combustion delays for ethanol–biodiesel fuel blends were measured. • For tested fuels, the DCN was determined. • A CVCC was used during the investigation. Abstract Growing interest in increasing the market share of renewable fuels results from the increasing consumption of fuels in various industries, especially in road transport. Such fuels include, for example, ethanol and FAME (Fatty Acid Methyl Esters), known as biodiesel. In diesel engines, ethanol, unlike biodiesel, cannot be directly used as a pure fuel due to its very low autoignition propensity. However, due to the good autoignition properties of biodiesel, increasing attention is being paid to the fuel constitution, for example, a blend of biodiesel with ethanol additive. This way, it is possible to obtain fuel for diesel engines that are compositions of only products of plant origin. In this paper, the autoignition properties of RME (Rape Methyl Esters) and ethanol blends, with the ethanol fraction up to 25% (v/v) were examined. A constant volume combustion chamber was used in the study. Under the specified test conditions, the ignition delay period and the combustion delay period, as well as the DCN (Derived Cetane Number), were determined for the individual blends. The average and maximum pressure rise rates in the combustion chamber were also analysed. The study has shown, for example, that with an increase of ethanol fraction in biodiesel, the periods of ignition and combustion delay increase. It was also shown that in the range from 5% (v/v) to 25% (v/v) of the ethanol fraction, for every increase in the fraction of ethanol by 5% (v/v), the DCN of the biodiesel–ethanol blend is reduced by an average of 3.4 units. [ABSTRACT FROM AUTHOR]

Highlights • Ignition and combustion delay period for n-butanol–diesel fuel blends was measured. • Tests of autoignition properties were conducted for different ambient gas temperatures. • Derived cetane numbers for fuel samples were determined. • During investigation, the constant volume combustion chamber was used. Abstract One of the methods of reducing the nitrogen oxides and smoke emissions from the exhaust gas of diesel engines is to use fuels containing an increased fraction of oxygen compounds. This can be achieved by adding oxygen compounds, in the form of alcohols, to a standard diesel fuel including, for example, ethanol, methanol and n-butanol. Due to a number of advantages over ethanol and methanol, n-butanol is of particular interest. Particularly important, in regard to the functioning of the diesel engine, is to determine, among others things, the autoignition properties of diesel fuel to which such alcohol has been added. In this study, the autoignition properties of blends of standard diesel fuel and n-butanol were tested, with n-butanol volume fractions of up to 25%. The tests were carried out in a constant volume combustion chamber, which allowed for the determination of the effect of the ambient gas temperature (in the range 550 °C–650 °C) on the ignition and combustion delay periods of the tested fuels. The average and maximum pressure rise rates, as well as the maximum pressure rise values in the combustion chamber, were also analysed. Investigations of the autoignition properties were supplemented with the derived cetane number and the Lower and Higher Heating Values of the tested blends. This study has demonstrated a number of properties relating to such mixtures, including that with an increase in the n-butanol volume fraction in the n-butanol–diesel fuel blend, the periods of ignition and combustion delay increase, and that an increase in the ambient gas temperature into which the fuel is injected shortens these periods to a varying extent. It has also been shown that in the range of 5%–25% n-butanol volume fraction, for each increase in n-butanol fraction of 5%, the derived cetane number of the n-butanol–diesel fuel blend reduces by, on average, 2.9 units. [ABSTRACT FROM AUTHOR]

One of the alternative fuels considered for powering piston internal combustion engines is ethanol. In some countries, ethanol has been successfully used for many years as a self-contained fuel in positive-ignition engines after relatively minor technical modifications. Due, among other things, to a very low cetane number, this fuel cannot be used in pure form in diesel engines. Consideration is being given to fuels that are blends of diesel fuel with some ethanol fraction. Diesel fuel containing up to 15% (v/v) of ethanol is sometimes referred to as e-diesel or oxygenated diesel. However, it is necessary to improve the autoignition properties of such a blend. Improvement of the autoignition properties of an ethanol–diesel fuel blend (EDB) can be accomplished by introducing an additive that improves the propensity for autoignition. One such additive may be 2-ethylhexyl nitrate (2-EHN), which is commonly used to improve the autoignition properties of diesel fuels. This study determined the effect of the addition of 2-EHN (up to 10,000 ppm [m/m]) on the autoignition properties of an EDB with an ethanol fraction of 15% (v/v). The study was carried out by using a device with a constant volume combustion chamber, which additionally enabled determination of the effect of the ambient gas temperature (in the range 550–650 °C) on the period of ignition delay and the period of combustion delay, as well as the derived cetane number. The average and maximum pressure rise rates in the combustion chamber were also analysed. Studies have shown that, with an increase of the 2-EHN fraction in an EDB, the periods of ignition and combustion delay decrease, and the increase in the temperature of ambient gas into which the fuel is injected shortens these periods to a varying extent. [ABSTRACT FROM AUTHOR]

Due to increasing fuel consumption in various industries, especially in road transport, interest in increasing the market proportion of renewable fuels is growing. The raw materials for production of ethanol may include sugar beets, sugar cane, potatoes and many other plants containing starch. In some countries, ethanol has been successfully used for many years as a self-contained fuel in positive-ignition engines after subjection to relatively minor technical modifications. Due, among other things, to a very low cetane number, this fuel cannot be used in diesel engines. For this reason, increasing attention is being paid to fuels that are blends of diesel with some ethanol fraction. Diesel fuel containing up to 15% (v/v) of ethanol is sometimes referred to as e-diesel or oxygenated diesel. In this study, the autoignition properties of blends of typical diesel fuel with ethanol have been tested with ethanol contents up to 14% (v/v) and where a constant volume combustion chamber was used. The study determined the effect of gaseous medium temperature in the range 550–650 °C on the period of ignition delay and the period of combustion delay. The average and maximum rates of pressure rise in the combustion chamber were also analysed. Studies have shown that, with an increase of ethanol fraction in diesel fuel, the periods of ignition and combustion delay increase, and the increase in the temperature of the gaseous medium into which the fuel is injected shortens these periods to a varying extent. [ABSTRACT FROM AUTHOR]

Due to increasing fuel consumption in various industries, especially in road transport, interest in increasing the market participation of renewable fuels is growing. One such fuel is ethanol. The raw materials for its production include sugar beets, sugar cane, potatoes and many other starch-containing plants. Ethanol can be used as a pure fuel in positive-ignition engines that have undergone relatively minor technical modifications. However, in compression-ignition engines, due to factors such as a very low cetane number and lubricity, ethanol cannot be used as a pure fuel. Therefore, increasing attention is being paid to fuel consisting of blends of diesel fuel with certain concentrations of ethanol. Diesel fuel containing up to 15% (v/v) ethanol is sometimes referred to as e-diesel or oxygenated diesel. In this paper, the lubricity of blends of conventional diesel fuel and ethanol, with ethanol content up to 14% (v/v), were tested. The HFRR ( High-Frequency Reciprocating Rig ) method was used for the research, which is a normative method of determining the lubricity of diesel fuel. For individual fuel samples, microscopic photographs of wear scar caused on test balls, along with the designation of areas that have been considered when measuring the diameters of wear scars, were presented. The obtained values of WSD ( Wear Scar Diameter ) were compared to the regulatory requirements for diesel fuels. Further measurements of kinematic viscosity, density and water content were conducted for individual fuel samples. The results showed that in the range of up to 14% (v/v), the proportion of ethanol in diesel fuel causes hardly any changes to its lubricity as determined by HFRR, and in addition, diesel fuel with up to 14% (v/v) added ethanol still meets the standard requirements in terms of lubricity. [ABSTRACT FROM AUTHOR]

The problem of poor air quality in urban areas has a negative impact on the health of residents. This is especially important during periods of smog. In Poland, as in other countries, the problem of poor air quality, especially during the winter season, is associated with a high concentration of particulate pollutants in ambient air (PM10, PM2.5). Sources of particulate emissions, in addition to solid-fuel boilers, include means of transportation, especially those equipped with diesel engines. In turn, during periods of strong sunshine (spring and summer), the problem of photochemical smog, whose precursors are nitrogen oxides NOX, arises in urban areas. Their main sources of emissions are internal combustion engines. Therefore, to improve air quality in urban areas, changes are being made in the transport sector, among which is upgrading the fleet of urban transport vehicles to low- or zero-emission vehicles, which are more environmentally friendly. In addition, measures that reduce the harmfulness of the transportation sector to air quality include the introduction of clean transportation zones, as well as park-and-ride (P&R) systems. The purpose of this article is to present the results in terms of PM10, PM2.5, and NOx emission reductions, implemented over a period of two years (2021–2022) in the area of the Rzeszow agglomeration, related to the modernization of the suburban bus fleet and the implementation of a P&R system for passenger cars. The results of the study were compared with the value of estimated emissions from coal-fired boilers used for residential heating and hot water, which also contribute to smog. Thanks to the implementation of the project, i.e., the replacement of 52 old buses with new buses of the Euro VI emission class and the construction of new P&R spaces, the total average annual reduction in emissions amounted to approximately 703.6 kg of PM10, approximately 692.7 kg of PM2.5, and a reduction of approximately 10.4 tons of NOX. [ABSTRACT FROM AUTHOR]

Due to increasing fuel consumption in various industries, especially in road transport, interest in increasing the market proportion of renewable fuels is growing. One of such fuels is ethanol. The raw materials for production of ethanol may include sugar beets, sugar cane, potatoes and many other plants containing starch. Ethanol can be used as a self-contained fuel in positive-ignition engines, which undergo relatively minor technical modifications. However, in diesel engines with compression ignitions, due to, e.g., a very low cetane number, this fuel cannot be used. Therefore, more attention is given to fuels consisting of mixtures of diesel fuel with certain proportions of ethanol. In this paper, the properties of autoignition mixtures of conventional diesel and ethanol, with ethanol content of up to 14% (v/v), were examined. A combustion chamber of constant volume was used in the study. The effect of injection pressure in the range of 80 MPa–140 MPa on the period of ignition delay and the period of combustion delay was determined in the study. In addition, for each mixture of diesel fuel and ethanol, the value of derived cetane number was examined. The studies have shown that with increasing proportions of ethanol, the ignition and combustion delays periods increase and the increase in fuel injection pressure in varying degrees shortens those periods. It was also shown that in the range of 14% ethanol, for every 2% increase in the proportion of ethanol, the derived cetane number of the mixture of diesel and ethanol is reduced by an average of 1.7 units. [ABSTRACT FROM AUTHOR]

• Lubricity tests using the HFRR method for the 1-butanol–diesel fuel blends were presented. • Microscopic photographs of the test ball wear scars were presented. • The lubricity tests were conducted at various fuel temperatures. • The results of the lubricity tests were referenced to the standard requirements. It has been shown that 1-butanol cannot be used as a self-contained fuel in typical diesel engines, mainly due to its low propensity for self-ignition and its low lubricity; thus, increasing attention is being paid to 1-butanol–diesel fuel blends (1-BDFs). In turn, considering the durability of fuel injectors, it is important to test the lubrication of fuels at increased temperatures, while varying the conditions under which the lubricating layer is formed. The article evaluates the lubricity of standard diesel fuel and 1-BDFs at temperatures of 30, 60, 90 and 120 °C. Tests were carried out for 1-BDFs at volume fraction of 1-butanol of 5, 15, 25%, using the high-frequency reciprocating rig (HFRR) method. For individual fuel samples, microscopic photos of the wear scar on the test balls are presented, along with the marked areas, which were taken into account when measuring the diameters of the wear scars. The wear scar diameter (WSD) values were adopted as the basic criterion for assessing lubricating properties. The results showed that larger fractions of 1-butanol in a blend contributed to improved lubricity at the highest sample temperature analysed, and the largest differences in lubricating properties at changes in the sample temperature were observed for neat diesel fuel (NDF) and for 1-BDF with a 5% 1-butanol volume fraction. Test results at 60 °C also showed that 1-BDFs with a 1-butanol volume fraction up to 25% meets lubricity requirements specified in EN 590 and ASTM D975. [ABSTRACT FROM AUTHOR]

Due to the increasing consumption of fuels in heavy industries, especially in road transportation, significant efforts are being made to increase the market participation of renewable fuels, including ethanol. In diesel engines, however, ethanol cannot be used as a pure fuel, primarily due to its very low cetane number and lubricity. For this reason, greater attention is being paid to blended fuels containing diesel and varying percentages of ethanol. Tests of lubricating properties carried out in accordance with the standard HFRR (high frequency reciprocating rig) method for ethanol–diesel fuel blends have long durations, which leads to ethanol evaporation and changes in the composition of the tested fuel sample under elevated temperatures. Therefore, this study presents an alternative lubricity assessment criterion based on the measurement of the scuffing load with a four-ball machine. Lubricity tests of blends of typical diesel fuel and ethanol, with ethanol volume fractions up to 14% (v/v), were conducted using a four-ball machine with a continuous increase of the load force of the friction node. In this method the lubrication criterion was the scuffing load of the tribosystem. The obtained results provided insights into the influence of the addition of ethanol to diesel fuel on lubricating properties, while limiting the ethanol evaporation process. The results also showed that an increase in the fraction of ethanol up to 14% (v/v) in diesel fuel resulted in a decrease in the scuffing load and a corresponding deterioration in the lubricating properties of the diesel–ethanol blend. For an ethanol volume fraction of 6–14%, the changes in the scuffing load were smaller than in ethanol volume fractions of 0–6%. [ABSTRACT FROM AUTHOR]

The COVID pandemic has caused a major exodus of passengers who chose urban and suburban transport. In many countries, especially in the European Union, there is a tendency to choose individual means of transport, causing damage to the environment and contributing significantly to greenhouse gas emissions. One method to promote urban transport is replacing bus fleets with newer ones, thus making public transport more attractive and reducing the emission of harmful exhaust fume components into the atmosphere. The aim of this study was to show a methodology for calculating CO2e for bus fleets. When determining CO2e, the principal greenhouse gases, such as CO2, CH4, and N2O, are usually considered. However, CO emissions also have indirect effects on climate through enhanced levels of tropospheric O3 and increased lifetime of CH4; therefore, CO2, CH4, N2O, and CO emissions were determined for CO2e emission calculations. Two bus fleet variant scenarios were analysed; the first non-investment variant assumed passenger transport using the old fleet without any P&R parking zones. The second scenario was based on the current state, which includes the purchase of new low-emission buses and the construction of P&R infrastructure. The calculations were performed using the COPERT emission model with real data from 52 buses running on 13 lines. For the analysed case study of the Rzeszow agglomeration and neighbouring communes, implementing the urban and suburban transport modernisation project resulted in a reduction in estimated CO2e emissions of about 450 t. The methodology presented, which also considers the impact of CO emissions on the greenhouse effect, is a new element of the study that has not been presented in previous works and may serve as a model for other areas in the field of greenhouse gas emission analyses. The future research scope includes investigation of other fuels and powertrain supplies, such as hydrogen and hybrid vehicles. [ABSTRACT FROM AUTHOR]

Road transport contributes to almost a quarter of carbon dioxide emissions in the EU. To analyze the exhaust emissions generated by vehicle flows, it is necessary to use specialized emission models, because it is infeasible to equip all vehicles on the road in the tested road sections with the Portable Emission Measurement System (PEMS). However, the currently used emission models may be inadequate to the investigated vehicle structure or may not be accurate due to the used macroscale. This state of affairs is especially related to full hybrid vehicles, since there are none of the microscale emission models that give estimated emissions values exclusively for this kind of drive system. Several automakers over the past decade have invested in hybrid vehicles with great opportunities to reduce costs through better design, learning, and economies of scale. In this work, the authors propose a methodology for creating a CO2 emission model, which takes relatively little computational time, and the models created give viable results for full hybrid vehicles. The creation of an emission model is based on the review of the accuracy results of methods, such as linear, robust regression, fine, medium, coarse tree, linear, cubic support vector machine (SVM), bagged trees, Gaussian process regression (GPR), and neural network (NNET). Particularly in the work, the best fit for the road input data for the CO2 emission model creation was the GPR method. PEMS data was used, as well as model training data and model validation. The model resulting from this methodology can be used for the analysis of emissions from simulation tests, or they can be used for input parameters for speed, acceleration, and road gradient. [ABSTRACT FROM AUTHOR]

Among the solutions that make it possible to reduce CO2 emissions in the transport sector, particularly in urban traffic conditions, are hybrid vehicles. The share of driving performed in electric mode for hybrid vehicles is highly dependent on motion resistance. There are different methods for determining the motion resistance function during chassis dynamometer testing, leading to different test results. Therefore, the main objective of this study was to determine the effect of the chassis dynamometer load function on the energy demand and CO2 emissions of a full-hybrid passenger car. Emissions tests according to the New European Driving Cycle (NEDC) were carried out on a chassis dynamometer for three different methods of determining the car's resistance to motion. The study showed that adopting the motion resistance function according to different methods, results in differences in CO2 emissions up to about 35% for the entire cycle. Therefore, the authors suggest that in the case of tests carried out with chassis dynamometers, it is necessary to also provide information on the chassis dynamometer loading function adopted for the tests. [ABSTRACT FROM AUTHOR]

The development of urban strategies for the reduction of environmental impacts and decarbonization requires ongoing monitoring from the local scale and further deployment of actions to improve transport demand (user characteristics and modal choice) and supply (infrastructure and services). The analysis of pollution sources and the evaluation of possible scenarios are preliminary to the mitigation of impacts. In particular, the study of geometrical and functional characteristics of infrastructures through micro-simulation allows understanding of which schemes can support the reduction of emissions and guarantee high levels of service (LOS), reducing the problem of vehicular congestion in urban areas. The present work focuses on the small-scale analysis of vehicular traffic emissions at a multi-lane roundabout road intersection and the comparison of geometric schemes (current and design) and use with a turbo roundabout scheme as traffic volumes changes. These volumes have plummeted due to the current COVID-19 pandemic. The results show that the geometric-functional modification of the roundabout intersection from a multi-lane to a turbo-roundabout intersection allows a reduction of up to 30% of the emissions considering the current composition of the traffic fleet in the city of Rzeszow in Poland. The proposed comparative analysis methodology can contribute to the drafting of sustainable urban mobility plans (SUMPs) proposing a set of investments for new road works and considering a number of scenarios with interventions that can be implemented in the medium and long term that can provide the incentive to reduce road congestion and vehicular emissions. [ABSTRACT FROM AUTHOR]