Understanding the ignition characteristics of binary hydrocarbon blends is essential for designing high-speed propulsion systems such as scramjets, where ignition under short residence time is a critical challenge. In this work, the ignition delay behaviour of ethylene-acetylene/air mixtures was examined through shock tube experiments and kinetic simulations under engine-relevant conditions. Ethylene was used as the primary fuel and blended with acetylene at 5%, 10%, and 20% by volume to form binary mixtures, at an equivalence ratio of 1.0, temperatures between 560–1030 K, and pressures of 2.5–9 bar. The ignition delay time was determined from peak pressure rise and CH* chemiluminescence behind the reflected shock. Unlike previous blended fuel studies dominated by saturated hydrocarbons, this work presents a comprehensive dataset for ethylene-acetylene blends at low to intermediate temperatures and increasing the acetylene fraction from 5% to 20% reduces the ignition delay time by up to 50–60% in the 700–850 K and 2–5 bar regime. Numerical simulations were performed using ANSYS Chemkin in a closed, homogeneous, constant-volume reactor with the NUIG, ARAMCO, LLNL, and San Diego mechanisms. The sensitivity and rate-of-production analyses reveal that ignition is governed by HO<sub>2</sub>–H<sub>2</sub>O<sub>2</sub> radical chemistry, with the thermal decomposition of H<sub>2</sub>O<sub>2</sub> triggering rapid OH formation. Acetylene enhances ignition by promoting the regeneration of HCCO radicals and accelerating the transition to chain-branching chemistry.

A new design solution – the front deflector – intended to improve the performance of the outer air seals of the low-pressure turbine is analyzed in this paper using steady Reynolds-Averaged Navier-Stokes (RANS) simulations of a three-stage, state-of-the-art LPT model, including inner and outer cavities. The regions near the casing in the LPT still show potential for improvement, mainly due to flow interactions associated with the outer air seals. One recent concept for improving these areas is the front deflector. The solution is to modify the front part of the cavity. Its operating principle is to introduce an additional labyrinth for the leakage while simultaneously minimizing the front cavity volume. In the paper, several scenarios for implementing this feature are analyzed, including reducing the front-cavity volume without a static fin and adding a static fin to create an auxiliary labyrinth. Furthermore, the effects on the flow and the potential improvements in LPT efficiency associated with the solution are discussed. The former reduces front-cavity recirculation and its interaction with the mainstream; the latter reduces seal leakage when the fin length is sufficient. Across three stages, the predicted changes in LPT isentropic efficiency are on the order of 0.03–0.06%, depending on the scenario.

With the growing trend toward electrification of urban transportation, electric mopeds are emerging as a key area for implementing alternative energy storage solutions. Among these, sodium-ion cells represent a promising and cost-effective alternative to traditional lithium-based batteries. Environmental regulations, limited lithium resources, and increasing market prices are driving the search for efficient and sustainable energy sources, making sodium-ion technology an attractive candidate. These cells are gaining significant attention from researchers and technologists due to their potential for widespread adoption. Recent studies have focused on the use of metal sulphides as viable anode materials in Na-ion cells, as well as on carbon materials derived from biomaterials for use in electrochemical supercapacitors. Capacitive properties of these materials were evaluated using techniques such as galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV). The cycling tests demonstrated high reversibility of reactions and strong specific capacitance, indicating good electrochemical performance. GCD analysis of sodium-based systems revealed high initial potentials and efficiency exceeding 90%, suggesting their suitability for long-term applications. Additionally, tests of supercapacitors indicated pseudocapacitive behaviour, further confirming the effectiveness of the studied materials. Overall, the results emphasize the strong potential of sodium-ion technologies for energy storage, particularly in applications requiring durability, such as electric mopeds.

This work presents a thermodynamic analysis of a six-stroke cycle implemented in Spark-Ignition (SI) engines. The cycle configuration comprises two distinct combustion phases: (1) initial combustion of a methane-hydrogen mixture under fuel-lean conditions (λ > 1), yielding exhaust gases containing residual oxygen, followed by (2) secondary hydrogen injection during the expansion phase to facilitate complete utilization of the remaining oxidizer. The investigation evaluates the system's thermodynamic performance through parametric variation of both the fuel composition (CH₄/H₂ ratio) and the equivalence ratio during primary combustion. The results obtained indicate that the changes in the peak temperature of the second part of the cycle are small, up to 60K relative to the mean value. The fuel mix with =3.0 showed the highest cycle efficiency at 50.73%, indicating the best performance among all cases. According to the data, better performance can be achieved by optimizing cycle parameters such as regeneration, intercooling, pressure ratios, and component efficiency in addition to raising the maximum temperature. In conclusion, better outcomes are not always guaranteed by higher temperatures. Increasing thermal input alone is not as important as designing and optimizing cycles efficiently.

The advancement of combustion engines is driven by stricter emission regulations (e.g., Euro/EPA standards), requiring innovations in lubrication. Modern oils must ensure wear protection, emission system compatibility (e.g., DPFs, SCRs) and fuel efficiency. This paper analyzes updates to ACEA, API, and OEM specifications, focusing on oxidation resistance, low-SAPS formulations, and fuel economy. The trend toward low-viscosity oils (0W-20, 0W-16) reduces friction but challenges lubrication under high loads. The study evaluates these changes’ impact on engine durability and future oil development amid tightening sustainability and emission norms. This article will analize lubricant requirments for passenger cars and light commercial vehicles.

The improvement of unleaded fuels in general aviation represents a significant milestone in the pursuit of establishing a greener and more sustainable air transportation system. Conventional aviation fuels, such as AVGAS 100LL, have TEL (Tetraethyl Lead) in their composition, which is used to increase the octane rating of fuel and improve the efficiency of piston engines used in aviation. However, these substances are considered toxic, and their emissions into the atmosphere have negative effects on the environment and human health. Therefore, very strict air quality standards have been established by the European Union and member states. Years of research and cooperation throughout the aviation sector have contributed to the elimination of lead-containing fuels from most aircraft used in general aviation operations. Most engines have already been certified for the usage of unleaded gasoline, and so are all new engines. Nevertheless, one-third of the engines currently in use in the EU are not certified to burn unleaded fuel. Besides the lead, other toxic compounds are also being emitted with exhaust gases like CO2, NOx, and UHC. In this article, the discussion is about the profits of pursuing a zero-lead policy within General Aviation and the risks associated with introducing a leaded avgas prohibition without a valid alternative.

This article describes the findings of a experimental study of the effect of the profile and angle of attack of the propeller blades on the operational parameters of the 3W 275 B2 CS piston engine of air. Forces, the head's temperature and the crank's speed were recorded during real time on a special test vehicle. The investigation involved different configurations of propellers (2 and 3 blades) and different speeds. This made it possible to evaluate the influence of the propeller geometry on the engine efficiency. The results have shown that the right selection of the angle of attack and the profile of the blades and their number significantly affects the reached parameters - especially the string and temperature distribution, which is important for the safety and durability of components of the propeller system. The developed research stand enables further research on the selection of flour propellers. The novelty of the work is the use of a new type of research stand to determine the changes in the value of the force obtained during tests for wide range of rotation speeds of the internal combustion engine shaft. The selection of propellers depending on the number of blades and their profile is very difficult to predict and you should always do it individually for each engine after testing. The profile and the number of propeller blades so much allows you to get high flexibility of the engine and a good propeller continuing depending on the speed of the shaft.

The article provides a detailed description of the design and key parameters of the GTM-120 turbine engine, along with flow calculations for this power unit at a selected operating point. These calculations were performed using GasTurb software, which is also capable of assessing nitrogen oxide emissions. Additionally, the article outlines the test stand and the methodology used to determine toxic compounds emitted by the engine. It analyzes the measured results of various exhaust components produced during the engine's operation, specifically focusing on the levels of nitrogen oxides and carbon oxides as influenced by rotational speed and temperature. Conducted studies have established a testing methodology for aviation turbine engines, based on the type of analyzer used. This methodology will facilitate the evaluation of other aviation turbine engines on stationary test stands.

This study evaluates the performance of aftermarket and OEM diesel particulate filters (DPFs) using a particle number counter (PNC) during stationary Periodic Technical Inspection (PN-PTI) tests. Several European countries have already implemented regulations requiring this test to ensure that vehicles equipped with DPFs meet the stringent particle number (PN) emission limits. In this work, measurements were conducted on various vehicles with new and conditioned DPFs. The results revealed significant variability in PN emissions, with some filters failing to meet the required limits. Key contributors to elevated PN levels were identified, including filter aging and inadequate conditioning procedures. Based on the findings, the paper proposes practical recommendations and diagnostic approaches to support compliance with PN-PTI test requirements.

The study contains an analysis of the acceleration process of a passenger vehicle equipped with an IC powertrain, aimed at determining a throttle control strategy that minimizes fuel consumption during acceleration while maintaining adequate dynamic performance. The first stage involved measuring traction parameters for a constant assumed engine power. The second stage focused on determining a control trajectory that would ensure minimal fuel consumption during acceleration. To achieve this the acceleration process was examined during a flexibility test in the speed range from 12.5 to 35 m/s, following an acceleration pedal control line related to the crankshaft rotation speed. Implementing the acceleration process along this control line resulted in a reduction in acceleration dynamics, accompanied by a decrease in fuel consumption per distance traveled by nearly 51%. An analysis of the average acceleration values for a given drivetrain gear ratio revealed that exceeding a throttle position of 70% yields no significant improvement in vehicle dynamics. The optimal throttle positions during acceleration were found to be within the range of 25% to 70%.