The presented diploma thesis deals with the measurement of car deceleration during engine braking from different starting speeds and different speed gears with a sample of vehicles. This piece of work consists of a theoretical part, where problem background is defined, selected driving parameters including the manner how to measure them are explained and the facts in the field of structural characteristics of the vehicle are given, further from a design of measurement methodology that gives an overall plan of implementation, all the respective information and a description of handling with decelerometer, further from a real measurement of the deceleration including an interpretation of partial obtained values and finally from the evaluation of all results with appropriate conclusions.

Diploma thesis deals with the deceleration of the motorcycles with the use of engine braking. Work can by divided into theoretical and practical part. The theoretical part begins with the possibility of division motorcycles according to several criteria. Below is given the primary papers of literature, usable in connection with the issue of this work. Subsequently, the work discusses the factors which are affecting the course of the deceleration with the use of engine braking. The practical part acquaints the reader with available measuring devices, with the place of measurement and the methodology. The following are listed specific measured values for individual motorcycles, supplemented with graphical output. At the end of the practical part is for comparison a brief summary of the measured values of each tested vehicle. Interpretation and evaluation of the measured data are contained in the conclusion of the work.

The present apparatus for the technical analysis of road accidents has no well-integrated information, recommendations or procedures of how to solve comprehensively the analysis of road accidents involving vehicles equipped with stabilization system of driving dynamics. The problem in the investigation of a vehicle movement in a curve is the ignorance of the contributions of vehicle dynamics intervention of the electronic stability system. Although some of the simulation software used in the analysis of road accidents makes it possible to take into account the modelled vehicle movement impacted by a stabilization system in the examined process, but the experts do not know what parameters should be entered in the numerical models of stabilization system in a computer programme. Therefore, the thesis investigates the issue of the expert analysis of vehicle riding and braking in a general spatial curve at speeds exceeding 50 kph with simultaneous examining the impact of electronic stability system chassis on vehicle driving dynamics. The thesis first deals with the solutions based on classical analytical methods, then dwells on experimental measurements in real conditions on testing grounds and, finally, addresses the use of computer simulation software in expert practice. Nevertheless, it is important to realize that no computer simulation software can be an absolutely unambiguous solver, and it is not enough to generate a computer simulation, but so obtained results should be evaluated and justified technically. Road accident analyst needs to know the impact of vehicle electronic stability control systems on vehicle movement. The thesis investigated the mutual relationship between the vehicle speed limit in a curve specified by analytical calculation and the vehicle speed in a curve experimentally detected by measuring the parameters of driving dynamics of a vehicle equipped with electronic stability system. The impact of selected electronic stability control systems of the chassis on the vehicle movement in the investigated processes in the curve was detected and quantified by driving experiments. Finally, the input values of significant quantities of computational models of the ESP simulation programs were found consistent with the results of experimental measurements in defined curves for the vehicles equipped with electronic stability systems. The results of the thesis can be used both in the expert and in the teaching activities.

The goal of this diploma thesis was the design of an assistance brake for a mechanical invalid wheelchair. The theoretical part includes the sorting of wheelchairs and available technology of braking systems. In the practical part, there was prepared the design and testing of the assistance brake. In the final chapter, the technical-economic evaluation of the designed solution was discussed and compared with the existing technologies.

Electric and hybrid vehicles uses regenerative braking, where application of the brake triggers the electric motor to work as a generator to produce electricity, which in turn charges the battery. This results in much less use of the friction brake, changing the corrosion and wear behavior of the rotor surface. There is a need for research on this topic, since fully electric or hybrid vehicles are replacing combustion engines due to concerns about global warming and climate change. Here the corrosion behavior of coated cast iron vehicle rotors in 3.5wt% NaCl is studied. The corrosion study has been performed using electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). All the coated samples were provided by Pure Forge Rotors. Based on the results from SEM and EDX, the coating is atomic forge proprietary coating, and the base material is gray cast iron. Our primary objective is to study the corrosion behavior of coated, non-coated and friction-tested samples. CV experiments indicate a shift in the corrosion potential and corrosion current density due to changes in the nature of the exposed surface. Cross-sectional SEM showed the thickness of the coating to be 16-23 µm. After friction testing, the friction layer created by rubbing the brake pad over the rotor plays a role in corrosion resistance, but this depends on the type of brake pad material (i.e. semi-metallic, non-asbestos organic and low metallic). Results showed that friction film that forms after testing against non-asbestos organic pads provides the highest corrosion resistance amongst the three brake pad materials.

A critical maneuver for a heavy vehicle is braking with different friction on the left and right hand side of the vehicle, called μ-split. This results in an unwanted yaw torque acting on the vehicle. During this situation, the driver maintains the lateral stability and follows the desired path by corrective steering. In anautonomous heavy vehicle the system must handle this situation by itself. The purpose of this thesis is to analyze how an autonomous vehicle can detect a μ-split situation and then use steering control to maintain its path and stability. Two methods for detecting a μ-split situation are presented where one is based on vehicle kinematics, this detector utilizes the difference in wheel speed between the left and right hand side of the vehicle. The other detector is based on lateral vehicle dynamics, this method uses a sliding mode observer to detect unexpected changes in the yaw rate signal. The detectors were tested in a real vehicle and the results showed that the kinematic detector was fast but had a small risk of false detection, while the dynamic detector was slower but more robust. An analysis of the desired steering behavior showed that the steady state during μ-split braking is to drive with a non zero body slip. If a kinematic path follower is used with kinematic error dynamics this will lead to a contradicting behavior since the body slip is equal to the heading error during straight line braking, assuming that the velocity vector of the vehicle is parallel to the path. Simulations showed that during a μ-split situation the Linear Quadratic pathfollower based on kinematic error dynamics manages to follow the path with a non zero body slip while keeping the path errors small. It has also been shown how the detection of a μ-split situation can be used to change control strategy. By introducing active yaw control or change the tuning on the controller after a detection a better result could be achieved.

Maintenance cost is one of the important issues in railway heavy haul operations. For the iron-ore company LKAB, these costs are mainly associated with the reprofiling and changing of the wheels of the locomotives and wagons. The main reason for the wheel damages is usually surface initiated rolling contact fatigue (RCF) on the wheels.The present work tries to enhance and improve the knowledge of the vehicle-track interaction of the Swedish iron-ore freight wagons and locomotives used at Malmbanan. The study is divided into two parts. Firstly, it is tried to get into the roots of RCF using the simulation model of the iron ore wagon (Paper A). Secondly, the study is focused on predicting wear and RCF on the locomotive wheels also via a dynamic simulation model (Paper B).In the first paper, some key issues of the dynamic modelling of the wagons with three piece bogies are first discussed and then parameter studies are carried out to find the most important reasons of wheel damages. These parameter studies include track design geometry, track irregularities, wheel-rail friction level, cant deficiency and track stiffness. The results show a significant effect of the friction level on the amount of RCF risk.As the locomotive wheel life is much shorter than that of the wagons, LKAB has decided to change the locomotive wheel profile. Two final wheel profiles are proposed; however, one had to be approved for the field tests. In the second paper, the long term evolution of the two profiles is compared via wear simulation analysis. Also, the RCF evolution on the wheel profiles as a function of running distance is discussed. The process is first carried out for the current locomotive wheel profiles and the results are compared with the measurements. Good agreement is achieved. Finally, one of the proposed profiles is suggested for the field test because of the mild wear and RCF propagation. / <p>QC 20150210</p>

Now a days, the society thinks about more sustainable and clean energy sources. Most of the countries in the world relay on non-renewable energy sources for the generation of electricity. This results in the scarcity of fossil fuels in future and also increases the production of carbon emissions. This thesis considers a metro system named Kochi Metro which is a rapid transit system serving in the city of Kochi in Kerala, India which uses renewable sources, mainly solar, for giving power to the Metro.In this thesis work, trying to analyze the measures adopted by Kochi Metro Rail project in potential reductions of energy consumption and energy generation both contributing to energy efficiency.With the help of Matlab, different levels of installed PV power are used to find out the possible self-usage, self-sufficiency, and energy neutrality of the system.

<p>  </p> <p>Historically, agencies have been reliant on physical infrastructure, crash data, manual data collection, and modeling to evaluate their road networks. Over the past several years, enhanced probe data has become commercially available and has shown itself to be a relatively inexpensive and scalable way to evaluate the performance of road networks. In January 2022 alone, 11.3 billion passenger vehicle trajectory waypoints and 279 million passenger vehicle event records were logged in the state of Indiana. This data, typically segmented into vehicle trajectory waypoints and vehicle event records, contains a variety of information including, but not limited to, location, speed, heading, and timestamp. </p> <p>One use for this enhanced probe data is the evaluation of traffic signals for safety improvements. Typically, agencies require 3 – 5 years of crash data to be able to statistically identify intersections in need of safety improvements. This study compared crash data over a 4.5-year period at 8 signalized intersections to one month of weekday hard-braking and hard-acceleration data from July 2019. A Spearman’s rank-order correlation test was used, and a strong to very strong correlation between event data and crashes could be found indicating that just one month of event data could be an adequate substitute for 3 – 5 years of crash data. </p> <p>The representativeness of this data is often a major concern for many agencies as the usefulness of the data is only as good as the data itself. This paper describes and demonstrates a methodology for measuring connected vehicle penetration using data provided by state highway performance monitoring stations. This study looked at 1.7 billion count station vehicle counts and 70 million connected vehicle records across 381 count stations in 11 different states (California, Connecticut, Georgia, Indiana, Minnesota, North Carolina, Ohio, Pennsylvania, Texas, Utah, and Wisconsin). Across the 11 states and 381 stations, the average percent penetration was 3.8% in August 2020 and 3.9% in August 2021. Drilling down to August 2021, the percent penetration observed among the 187 interstate stations varied from 1.6% in Indiana to 10.0% in Wisconsin. A similar comparison of 162 non-interstate count stations showed a variation of 2.1% in MN and 18.0% in WI on non-interstates. </p>

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