Assessment of the Braking System Damage in the Public Transport Vehicles of a Selected Transport Company

This paper analyzes damage to safety systems over a five-year period for a group of vehicles. In the first step of analysis, descriptive statistics characterizing the analyzed variables were calculated and analyses related to the assessment of damage to the braking system. The analyses were carried out in order to examine the relationship between the mileage of vehicles and the number of defects quarterly and monthly and the fit of the obtained empirical results of the analysed variables to a normal or other theoretical distribution was checked. In order to check whether the observed differences in the mean values of the number of failures of the safety systems are statistically significant, a non-parametric analysis of variance was performed. The Kolmogorov-Smirnov test was applied, the distribution of the monthly sum of the braking system faults, distribution of the sum of the braking system faults from individual quarters, distribution of the monthly kilometrage of all vehicles and distribution of the quarterly kilometrage of all vehicles were presented. After describing previous correlation analyses, a linear regression analysis was conducted in which a model was built to predict the number of braking system faults based on monthly vehicle mileage and month of measurement. The last part of the analysis was to verify whether the number of the braking systems faults depends on the season of the year and it was checked whether the season makes any difference to the vehicle's quarterly kilometrage. One-way analysis of variance (ANOVA) was carried out to this end

Prediction of Road Accident Risk for Vehicle Fleet Based on Statistically Processed Tire Wear Model

The goal of the paper is to investigate the impact of tire tread depth on road accident risk and to develop an accident rate prediction model. The state of 4288 vehicle tires using tread depth gauge was inspected and processed statistically. The tread depth of the most worn tire from each vehicle was registered for further analysis. Based on the collected data, a statistical tire tread depth model for an insurance company vehicle fleet had been developed. The conformity of the gamma distribution to the data was verified upon applying the Pearson compatibility criterion. The paper provides the histograms of the frequencies of tire tread depths and the theoretical curves of the distribution density. The probability of the accident risk depending on the tire tread depth (adaptive risk index) was calculated applying the formed distributions and risk index dependence on the tire tread depth for the inspected vehicle fleet. According to the developed prediction model, an upgrade of the regulation for the minimum allowed tire tread depth by 2 mm (up to 3.6 mm) could reduce road accident risk (caused by poor adhesion to road surface) to 19.3% for the chosen vehicle fleet. Such models are useful for road safety experts, insurance companies and accident cost evaluation specialists by predicting expenses related to insurance events

SIMULATION OF COMPONENTS MIXING IN ORDER TO DETERMINE WORKING BODIES RATIONAL PARAMETERS

One of important things in the production of vitally foods is bakery industry. The quality of baked goods can be achieved by improving the quality of dough kneading. In order to achieve this goal a new structure of the working body and methods of mathematical and computer modelling are offered, aimed to determine the working body design factors and visualize the process. Mathematical models of the dependency of dough viscosity from working body structural features and the frequency of its rotation are made. The obtained models are used to determine rational values of controlled parameters. It has been found that for wheat dough mixing the use of equipment with pin working bodies is more preferable. One of them – the main one – is larger in diameter, and two others – supporting ones – are smaller, able to ensure effective implementation of first and second stages of components mixing. The necessity of changing rotation direction of working bodies is substantiated. At the initial stage of mixing it is necessary to ensure larger diameter pin heating and at the stage of plasticization – vice versa – smaller diameter pins heating

Analysis of Pollutants Emission into the Air at the Stage of an Electric Vehicle Operation

The article discusses the research on CO2 emissions at the stage of electric engine vehicle operation. The operation stage includes, among others use of the vehicle as well as maintenance and charging for the vehicle’s propulsion. The origin of the electricity consumed during charging has an impact on the vehicle’s emissions balance. The scope of considerations concerns coal as the main energy carrier in Poland. The obtained results can be a benchmark for comparing other primary energy sources used for electricity production. Based on the collected technical data of electric cars, the values of CO2 emission factors from electricity production in thermal power plants and data on the state and structure of electricity production in Poland, an analysis of CO2 emissions from electric vehicles in the operational stage was performed. The vehicle’s electricity consumption of 0.14–0.16 kWh/km is accompanied by CO2 emissions of 100.94–115.36 g/km. The calculated CO2 exceeds the EU limit value from 01/01/2020 (95 g/km) for average CO2 emissions from new passenger vehicles. The main message of the work is the statement that increasing the efficiency of the electricity generation process in commercial thermal power plants in Poland will translate into a reduction in the emission of electric cars consuming this energy for propulsion. The research shows that the change in the efficiency of energy transformations in a thermal power plant from 38% to 46% leads to a reduction in the emission of an electric vehicle by over 17%. The emission of CO2 from a passenger car with a compression-ignition engine is discussed. The considerations include the stage of the use of the vehicle and the stage of production of diesel oil, which is consumed during the use of the vehicle