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Effect of different types of bicycle tires on energy expenditure
Hejrová, Karolína ; Jindra, Matouš (advisor) ; Baláš, Jiří (referee)
Title: Effect of different types of bicycle tires on energy expenditure Objectives: The aim of this bachelor thesis is to determine the difference in energy expenditure when using different types of bicycle tires. Methods: The research group consisted of 5 males in age 26,4 ± 2,2 years. This was an experiment. The calculation of energy expediture was based on the amount of oxygen consumption (VO2) and exhaled carbon dioxide (VCO2), i.e. indirect calorimetry. For the analysis of respiratory gases MetaMax 3B measuring device was used. Three types of bicycle tires were tested. The test ride was carried out in laboratory on the cycling rollers. Probands completed one test ride (with a cadence of 80 rpm) on each type of tires. Test ride lasted on average 4:55 ± 1:50 min. For results were processed values of 4 minutes steady state VO2. Results: We found out the significant difference in energy expenditure between ride with road tires and ride with Fat Bike tires, and also between ride with trekking tires and ride with Fat Bike tires. The difference between ride with road and trekking tires was, due to the standard error of measurement, insignificant. Conclusion: The energy expenditure reached a significant increase while using tires with the largest contact patch compared to using tires with the smallest...
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Design of Device for Tyre Rolling Resistance Measurement
Piskoř, Martin ; Blaťák, Ondřej (referee) ; Hejtmánek, Petr (advisor)
The aim of this thesis is a construction concept of tyre rolling resistance measuring device. The first part deals with the rolling resistance. It describes its causes, its influential factors and it also includes rolling resistance identification methods. The second part deals with construction design of the rolling resistance measuring device itself. It contains stress analysis, and fatigue analyses as well. It includes selection of transducers used for tyre rolling resistance measuring and also measurement error analyses. The last part focuses on estimated financial requirements connected with producing and assembling the designed measuring device.
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The engine unit of forestry harvestor
Petr, Tomáš ; Škopán, Miroslav (referee) ; Kašpárek, Jaroslav (advisor)
At the beginning of bachelor´s thesis is description of harvester and its main parts. Then research of four six – wheeled forestry harvesters was developed. Features of compared harvesters are similar to the task. The next point was theoretical part with equations needed for calculation of rolling and inertial resistances. Based on the theory an enumeration of powers of particular driving modes was done. Then performances for work devices of harvester were calculated. From the single values were determined total powers of machine, which were transparently organized into table and graph. Based on the maximal total power were chosen three appropriate engines. From the three was selected the most suitable one.
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The engine unit of a loader
Koksa, David ; Škopán, Miroslav (referee) ; Kašpárek, Jaroslav (advisor)
The work is focused on loading construction machinery and their engine units. The theoretical background research introduces the domain of wheeled loaders. Subsequently, three specific machines, which are available on the market, are selected from a similar model range. They are selected according to the specified technical criteria. Individual power requirements for various modes of operation are calculated according to a suitable algorithm. These power requirements are summed up to obtain the needed total power. Based on the calculated value of the total power the suitable engines from various producers are proposed at the end of this work. This was the goal of the work.
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Software for Optimalization of Gear Speed
Pokorný, Pavel ; Beran, Martin (referee) ; Svída, David (advisor)
Rolling vehicle is being influenced both by driver and many other factors of physical nature. These factors affect the whole behavior of the car, its performance, fuel consumption etc. It is very reasonable to cope with these factors then. The main aim during vehicle evolution (both civil and racing ones) is to optimize the influence of all invisible enemies as much as possible. The aim of this work is a description of factors influencing the moving vehicle. Several practical examples are included. The theory of transmissions is fundamental to the programme for creating a saw-diagram and gear speed optimization. Finally a few analysis of the real vehicles and subsequent evaluation will be done. The output of the work is an overview of factors affecting the moving vehicle, the results of performed analysis and programme for optimization of gear speed.
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