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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]

The article presents findings of the comparative analyses of the selected physicochemical parameters of diesel fuel and diesel-ethanol blends with the addition of dodecanol, used to stabilise the blend Diesel fuel and the blends were tested for density, flash point, and cold filter plugging point. The physicochemical properties were assessed in seven samples with different proportional volumes of ethanol contained in diesel fuel. Homogeneous blends were produced by adding 5% dodecanol to blends containing between 5% and 30% ethanol. The study was conducted to assess the selected physicochemical properties of diesel-ethanol blends with the addition of dodecanol and to compare the obtained results with the requirement of EN590:2022-08. [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]

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]