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• 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]

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]