A problem has been noted regarding the admixture of fuel to a low viscosity lubricant in hybrid electric vehicles (HEVs). This is very detrimental to the wear and tear of engine operating components. In this study, the operating conditions of HEVs were analysed. Using X-ray fluorescence spectrometry (XRF), engine oils of two different viscosity classes were compared after the operating process and these data were compared with fresh reference samples. Attention was paid to the content of elements such as Ca, Zn, Mo, Sn, Cd, Fe Pb, Si, Cu, and Ni. The depletion of anti-wear additives, as well as the higher content of metallic wear products relative to the operated 5W30 (engine oil), contributed to the overall assessment of the lubricity of the 0W30 oil, as well as to the tribological results. Then, under laboratory conditions, oil samples contaminated with up to 1 to 8% fuel were subjected to rheological (mini AV-X viscometer) and tribological (four-ball tester) tests. The dependence of the local pressure at the metal-to-metal contact point in the kinematic node on viscosity showed the dissimilar nature of the used and fresh oil and the divergence of the domains for the two groups of samples. Increasing the fuel contamination of used oil above 4% drastically reduces the pressure responsible for maintaining the oil film. In order to improve lubricant performance during HEV operation in urban conditions, it was proposed to carry out extra-urban traffic driving in order to evaporate the fuel from the engine oil. A shorter oil change interval is also recommended.

The article presents methodology for testing the traction parameters of the vehicle on the laboratory stand. The tests have been carried out using MAHA LPS 3000 chassis dynamometer. Power output can be measured in two ways, at steady state or during acceleration. Both have benefits as well as drawbacks. Car manufacturers are required to use steady state tests for certification of power output. It has an advantage as it is a well defined test that is easy to repeat and verify. The problem with results measured during acceleration is that the acceleration itself has a considerable effect on the result.

This article presents a research methodology that supplements known studies to solve the problem of a correct complementary analysis of vehicles with different drive units. This method can be used at the stage of selecting a car for specific tasks, as well as for in-service technical condition checks. A new method is proposed for analysing the impact of operating conditions on the mileage fuel consumption, unit fuel consumption and overall energy efficiency of vehicles. In the study, it was possible to determine the effect of changing the vehicle speed, road gradient angle and vehicle weight. Tests identifying fuel consumption and efficiency characteristics as a function of vehicle load were carried out using passenger cars with different drive designs. Carrying out tests under laboratory conditions on a chassis dynamometer bench enabled the precise determination of the change in operating conditions. The criteria adopted for the evaluation included fuel consumption and overall vehicle energy efficiency. The variable parameters included speed, vehicle weight, and the road gradient angle. The data for criteria calculation were acquired using a diagnostic tester with a functional parameter recording function. The application of the presented method enabled a comparison of the overall energy efficiency of two vehicles equipped with spark-ignition combustion engines, according to the criteria listed. The experiment showed that in a three-cylinder engine, unit fuel consumption is more sensitive to parameter changes under identical conditions (speed, vehicle weight, road gradient angle) than in a four-cylinder engine. To evaluate the drive units of the test vehicles, characteristics of changes in the overall energy efficiency were used as well. It was observed that in all testing variants, the value increased with increasing road gradient values, with the intensity of η increase not being constant. A car with a four-cylinder engine has a higher energy efficiency at low loads. The proposed methodology is relevant for evaluating vehicles with different drive systems (including hybrid) and adapting drive characteristics to the operating conditions. Partially the presented methodology can also be transferred to EV vehicles - in terms of energy efficiency.

The paper analyzes vehicle structural solutions that are consistent with emission standards, modern energy efficiency norms, safety requirements and consumer expectations. Powertrain parameters in a vehicle with an internal combustion engine were selected based on the following criteria: fuel consumption, engine dynamics, and emission standards for harmful substances. A light-duty passenger vehicle with gross vehicle weight rating (GVWR) of 3.5 tons was modified by replacing a spark-ignition engine with a diesel engine. The gear ratio in the powertrain had to be modified accordingly to optimize the engine’s performance, enhance engine dynamics, minimize fuel consumption and toxic emissions. Selected powertrain parameters were optimized based on standard driving cycle requirements, speed profiles and the road gradient during tests conducted under real-world conditions.

This study analyzes the influence of FDM printing temperature on the wear properties of the PA-12 polyamide under dry friction conditions and in the presence of an abrasive slurry. Tests were carried out using the ball-cratering method at three extrusion temperatures (255 C, 260 C, and 265 C). Under dry friction conditions, the highest wear rate was recorded for samples printed at 255 C, while increasing the printing temperature to 260 C and 265 C progressively reduced the wear intensity. A similar decreasing trend was observed when friction occurred in the presence of an abrasive slurry, where higher printing temperatures led to significantly lower wear rates. This behavior can be attributed to improved interlayer bonding, enhanced structural cohesion, and reduced material porosity at elevated processing temperatures, which collectively increase the resistance of the material to both adhesive and abrasive wear mechanisms. Analysis of wear mechanisms revealed adhesion dominance under dry friction and abrasive wear in the presence of abrasive particles. The results confirm the significant impact of printing parameters on the tribological durability of FDM-manufactured components.

Determining the exact values of the rolling radii of the wheels is extremely important in terms of the functioning of the safety systems of modern vehicles. It is on the basis of the rotational speed of the vehicle wheels that the traction parameters of the vehicle are determined, as well as the...