The utilization of hydrogen for reciprocating internal combustion engines remains a subject that necessitates thorough research and careful analysis. This paper presents a study on the co-combustion of hydrogen with diesel fuel and biodiesel (RME) in a compression-ignition piston engine operating at maximum load, with a hydrogen content of up to 34%. The research employed engine indication and exhaust emissions measurement to assess the engine’s performance. Engine indication allowed for the determination of key combustion stages, including ignition delay, combustion time, and the angle of 50% heat release. Furthermore, important operational parameters such as indicated pressure, thermal efficiency, and specific energy consumption were determined. The evaluation of dual-fuel engine stability was conducted by analyzing variations in the coefficient of variation in indicated mean effective pressure. The increase in the proportion of hydrogen co-combusted with diesel fuel and biodiesel had a negligible impact on ignition delay and led to a reduction in combustion time. This effect was more pronounced when using biodiesel (RME). In terms of energy efficiency, a 12% hydrogen content resulted in the highest efficiency for the dual-fuel engine. However, greater efficiency gains were observed when the engine was powered by RME. It should be noted that the hydrogen-powered engine using RME exhibited slightly less stable operation, as measured by the COV_IMEP value. Regarding emissions, hydrogen as a fuel in compression ignition engines demonstrated favorable outcomes for CO, CO₂, and soot emissions, while NO and HC emissions increased.

The search for alternative fuels that can limit the use of traditional fossil fuels to power internal combustion engines is one of the main tasks faced by both the modern automotive industry and the modern energy industry. This paper presents experimental tests of a compression ignition engine, in which the conventional fuel, i.e., diesel, was partially replaced with propyl alcohol, i.e., a renewable biofuel. Studies on the co-combustion of diesel fuel with propanol were carried out, in which the energy share of alcohol varied from 0 to 65%. The research showed that an increase in the proportion of propanol, up to 30%, resulted in a significant increase in the rate of heat release and the rate of pressure increase in the cylinder of a compression-ignition engine. Increasing the alcohol content to 65% resulted in an increase in the ignition delay time and significantly shortened the duration of combustion. During the combustion of diesel fuel with a 50% propanol share, the engine was characterized by maximum efficiency, higher than diesel fuel combustion by 5.5%. The addition of propanol caused a slight deterioration of the combustion stability determined by the coefficient of variation for IMEP. The study of engine exhaust emissions has shown that the combustion of diesel fuel with a small proportion of propanol, up to 30%, causes an increase in nitrogen oxide emissions, while up to 50% contributes to a decrease in HC emissions. The increased share of alcohol contributed to a significant decrease in the emissions of both carbon monoxide and carbon dioxide, and caused a significant reduction in the concentration of soot in the exhaust of the compression-ignition engine.

In recent years, the interest in renewable fuels has increased mainly due to regulations regulating the permissible limits of toxic components of exhaust gases emitted by reciprocating engines. This paper presents the results of a comparison of the effects of fueling a compression-ignition piston engine with a mixture of diesel fuel and n-butanol, as well as RME (Rapeseed Oil Methyl Esters) biodiesel and n-butanol. The tests were carried out for a constant load and a wide energetic share of fuels in the mixture. The main focus was on the assessment of combustion stability, the uniqueness of the combustion stages, and the assessment of the fuel type influence on the CA50 angle. The tests show that RME offers the possibility of efficient combustion with n-butanol with up to 80% energy share. The share of n-butanol has a positive effect on the engine’s efficiency and very effectively reduces soot emissions. Without the influence on COV_IMEP, the share of n-butanol up to 40% in the mixture with diesel fuel and up to 80% in the mixture with RME was recorded. Combustion of RME with n-butanol was more stable. The share of n-butanol in the mixture with diesel fuel caused an increase in NO_x emissions, and co-combustion with RME caused a decrease in emissions.

The paper presents the results of research performed on an internal combustion diesel engine operating on a dual-fuel strategy. Fuels used during the study were diesel as a reference fuel, pure hydrogen, and ammonia as a hydrogen carrier. Fuel mixtures of diesel/hydrogen and diesel/ammonia were added to the engine, at energetic shares of 8, 12, 22, and 32% to maintain the constant engine load compared to the engine fueled with diesel. A comparison of the engine performance and the combustion process was made. Under the test conditions for all mixtures, the indication of the combustion pressure was made. The indication results were used to calculate engine performance parameters, such as IMEP, engine power, COVIMEP, and thermal efficiency. They were also used to describe the combustion process, including the determination of parameters like combustion stages, 50% MFB position, and HRR. The analysis of the results shows that adding hydrogen or ammonia as a main fuel causes a much faster combustion process compared to a diesel fuel engine. With an increase in energetic share, the combustion characteristic of the diesel/hydrogen engine shows two maxima in the HRR curve, besides 32% where there is only one peak. In contrast, for the diesel/ammonia engine, there is only one maximum, where an increase in the value of the kinetic combustion phase and the delay of ignition occur.