This scientific study is focused on the analysis of an influence of the experimental diesel fuel mixtures containing various portions of the biocomponent on the unregulated gaseous emissions generated by a diesel motor vehicle, which is equipped with the diesel engine utilizing the direct fuel injection system “common rail”. The main reason for the choice of this engine type was its wide usage in the current vehicles. The experimental diesel fuel mixtures were created as a mixture of the standard low-sulfur diesel fuel with the biodiesel, using various mixing ratios. The experiments were realized by means of a special 13-regime engine test cycle, which was intentionally developed for the diesel combustion engines. All the individual experiments were performed on the base of the given test cycle with 13 different operational modes. The obtained results offer a complex view on the generation of the unregulated emissions with regard to the operational conditions and taking into consideration operational loading of the given experimental engine.

Large transoceanic ships use marine ancillary diesel engines for generating electricity, which, on the other hand, produce a remarkable amount of harmful emissions during the combustion process. The International Maritime Organisation (IMO) establishes standards that limit the amount of harmful emissions produced during the engine combustion cycle in maritime transport. Because of this restriction, new alternative fuels entered the market. Experiments had been performed with various testing fuels created from biodiesel and ULSD-F (Ultra Low Sulphur Diesel-Fuel) in the ratios of 0%, 50%, 80%, and 100%. During the tests, the engine ran at different speeds and loads so that the mixed fuel influence on engine operation could be observed in detail and investigated.

The scientific contribution is focused on the analysis and optimization of combustion conditions concerning the dual-fuel mixtures. The greatest attention was paid to the temperature of intake air when a mixture of ethanol and gasoline created the applied fuel. An experimental fuel mixture was added into the intake pipe and ultra-low sulphur diesel fuel (ULSDF) was added directly into the engine cylinder using the CR (common rail) injection system. The article analysed the medium- and high-level operational engine load, whereby the engine timing parameters originally corresponded to a conventional diesel engine. The obtained results of the performed analysis showed that the temperature of intake air affected the following operational parameters: delay of ignition, pressure rise rate in the engine cylinder and the maximum level of pressure in the engine cylinder. Lower values of the intake air temperature enabled higher injection speeds for the ethanol–sustainable mixture (ESM), especially at high engine loads. An increase in the injection speed was possible due to lower charge air temperature. While there were reduced nitrogen oxide emissions, we also noted a reduction in both carbon monoxide emissions and the total amount of unburned hydrocarbon emissions.

The presented scientific study is focused on a complex analysis of power output and emission parameters concerning an experimental motorcycle. In spite of the fact that there are at disposal considerable theoretical and experimental results, which include also matters of the L-category vehicles, there is, in general, a lack of data covering the experimental tests and power output characteristics of racing, high-power engines that represent a technological peak in the given segment. This situation is caused by an aversion of motorcycle producers to publicize their newest information, especially in the case of the latest high-tech applications. The given study is focused on all the main results obtained from the operational tests performed on the motorcycle engine in two testing cases: first with the original arrangement of the installed piston combustion engine series produced and second with the modified engine configuration proposed in order to increase the combustion process efficiency. Three kinds of engine fuel were tested and mutually compared within the performed research work: the first was the experimental top fuel used in the world motorcycle competition 4SGP, the second was the sustainable experimental fuel, the so-called superethanol e85 developed for maximum power output and minimum emission, and the third was the standard fuel, which is commonly available at gas stations. Applicable fuel mixtures were also created with the aim to analyze their power output and emission parameters. Finally, these fuel mixtures were compared with the top technological products available in the given area.

The transportation sector is a significant contributor to global greenhouse gas (GHG) emissions, accounting for approximately 14 % of all anthropogenic GHG emissions. Despite the increasing popularity of electric vehicles, internal combustion engines (ICEs) continue to dominate the global vehicle fleet, making it essential to find a way to reduce GHG emissions from this sector. One potential solution is the use of efuels, also known as synthetic fuels, which can significantly reduce GHG emissions from transportation. While there are still several challenges associated with their production and use, the benefits of efuels make them a solution worth pursuing. Continued research and development are necessary to improve the efficiency and cost-effectiveness of efuel production and to ensure that they are a sustainable and environmentally responsible solution for the future of transportation. This paper will explore efuels and their potential to decarbonize the transportation sector.