This study presents an experimental investigation into the impact of blending bioethanol (E100) with conventional gasoline (E0), incrementally increasing biofuel levels up to E10, E50, and E70. The test was carried out in two stages: Stage I assessed the engine’s performance under fixed speeds (n = 2000 rpm and n = 2500 rpm) and fixed throttle positions (15%, 20%, and 25%) to measure changes in engine torque, efficiency, and environmental metrics by varying the concentration of bioethanol in the fuel. Stage II aimed to enrich the initial findings by conducting an additional test, running the engine at a fixed speed (n = 2000 rpm) and braking torque (M_B = 80 Nm) and varying the ignition timing. Results indicated slight improvements in engine brake torque and thermal efficiency (up to 1.7%) with bioethanol content increased to 70%, and a notable reduction in incomplete combustion byproducts—carbon monoxide and hydrocarbons emissions (up 15% and 43%). Nitrogen oxide emissions were reduced by up to 23%, but carbon dioxide emissions decreased by a mere 1.1%. In order to increase thermal efficiency by adding higher bioethanol blend concentrations, adjusting the ignition timing to counter the longer ignition delay is necessary; however, higher emissions of nitrogen oxides and hydrocarbons are a major drawback of such a strategy. The results of the research are important in determining the optimal concentration of bioethanol in the mixture with gasoline for the energy and environmental sustainability of a spark ignition engine.

During the road accident analysis speed of the examined vehicle often is being established in accordance with the length of the trace remained by the vehicle tires. Usually in such case there are values of braking deceleration used for calculations, which are selected from the corresponding references. The real experiment, establishing the braking parameters of the given vehicle, is performed more seldom. In both cases it is important to calculate the vehicle speed in accordance with the received or found values of deceleration as well to estimate the possible limits of the vehicle speed, i.e. to evaluate the veracity of such calculations. This paper presents the results of evaluation of car braking parameters, which are treated as random values in the known probabilistic characteristics.

This article analyses the factors that considerably influence the efficiency of automobile technical exploitation. It has been noted that automobile technical exploitation is basically determined by the following factors: the system and organizational level of automobile technical maintenance and repairs; the level of service basis; qualification of the staff; the level of stock and supply; the structure and age of automotive fleet and conditions of exploitation. This article presents the analysis of the first factor. The factor is significant enough and does not involve big investments. A theoretical analysis of the system of automobile technical maintenance and repair has been carried out. According to the nature of automobile technical maintenance and repairs two strategies are possible: the planned-preventive and the mixed type. Applying the first strategy the exact number of operations is being planned ahead, but the amount of work remains unknown. According to the second strategy the technical condition of an automobile has to be checked before starting technical maintenance and repair and only then the exact number of operations can be defined. The second strategy makes it possible to save spare parts, materials and time. This strategy, however, can be applied to the automobiles that are in good technical condition. The analysis of automobile technical maintenance and repair organization has shown that in order to improve the efficiency of automobile technical maintenance and repair the laws of mass service theory should be applied.

In this research, an experimental study is presented, which extends the usage of eddy current and load sensors in progressive stamping tools to optimize and continuously monitor the stamping process. The purpose of the research was to automatically detect material scrap before it leaves imprints on the part and based on the sensor’s readings, determine the optimal tool bottom position. The scrap thickness that needs to be detected was established in an experiment by visual evaluation of the result. To determine the optimal bottom position, a linear regression method was used, and the results were evaluated by part quality parameter. The research results consist of separate detection steps and the conclusion was made only after the serial type production. Overall results of scrap detection were influenced by the design of the existing tool. The bottom position detection consists of various readings interpretations and multi-step method descriptions. Based on the acquired results of both methods, implementing the in–die sensors was considered successful and applicable to new tools.

This article presents an experimental study focused on the impact of supplementing pure gasoline (E0) with bioethanol, gradually increasing the biofuel concentration up to 70% (E10, E50, and E70). The research was conducted in two phases: In the first phase (Part I), the engine's operation involved varying engine speeds (n = 2000 rpm, n = 2500 rpm) and adjusting throttle openings (15%, 20%, 25%) to analyze changes in brake torque, thermal efficiency, and ecological indicators. The second phase (Part II) aimed to complement and clarify the study data. Here, the engine was maintained at a constant speed (n = 2000 rpm) and brake torque (MB = 80 Nm) while altering ignition timing. The findings revealed that increasing the bioethanol concentration up to 70% led to modest enhancements in engine brake torque and thermal efficiency. However, the most significant impact was observed in the reduction of greenhouse gas emissions and incomplete combustion byproducts. The study also established that achieving higher thermal efficiency requires compensating for the extended ignition delay phase resulting from bioethanol addition by advancing ignition timing. Nevertheless, this approach is constrained by the escalating emissions of carbon dioxide and hydrocarbons. These findings provide valuable insights into optimizing the balance between bioethanol supplementation, engine performance, and environmental sustainability in spark ignition engines.