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In my diploma thesis I describe factors influencing fuel consumption in road freight transport and possibilities of optimizing fuel consumption. In the introduc-tion, I deal with ways to measure fuel consumption with telematics support. In the next part I focused on the description of truck driving assistance systems focusing on reducing fuel consumption. The following is a proposal for the methodology of track-based fuel consumption using telematics. The work continues with the prac-tical part, which deals with the measurement of the consumption of trucks with assistance systems and the influence of their adjustment on the consumption of trucks.

The dissertation thesis is focused on the investigation of the influence of inert gases on characteristic parameters of the combustion process. Inert gases are usually standard components of alternative gaseous fuels such as the producer gas, coal gas or biogas. For a long period some of the fuels were considered as waste gases and their potential was not sufficiently utilised. Compared with noble fuels such as natural gas, alternative fuels have different physical-chemical properties. For example, their lower heating value (LHV) can be lower even than 10 MJ/mN3. The composition of the alternative gaseous fuels can be various during their production process. Lower LHV is a result of the occurrence of inert gases that does not take a part in the combustion reactions. Inert gases have the ability to accumulate the heat. Under certain conditions it is possible to combust alternative fuels on conventional burners, but due to their different properties, problems can occur during the combustion. E.g. to achieve the same heat output as with the noble fuel, it is necessary to burn bigger volume of the alternative fuel. However, the limiting factor could be the burner's head geometry. Theoretical introduction of the thesis summarizes research results in the field of low calorific gaseous fuels combustion and the addition of inert gases into the noble fuels. The thesis also describes the mechanisms of the NOx formation and summarizes techniques which can be used to reduce NOx formation. Furthermore, fuels from alternative sources are categorized and described, including their composition and characteristics. Their physical-chemical properties were obtained by means of the combustion simulation carried out in the simulation software. Two devices had to be designed and manufactured to fulfil goals of the dissertation thesis. The first is a gas mixing station capable of mixing 4 different components. The second device is a burner utilized for the combustion of low calorific fuels. The key section of this thesis is a chapter describing the experimental plan, the performance and the evaluation of the experiments. The goal of the experiments was to dilute the natural gas by two inert gases, namely carbon dioxide and nitrogen. The lowest LHV value achieved during the experiment was 10,7 MJ/mN3. The influence of the inert gases on the NOx emissions, the flame stability and characteristics, the flue gas temperature, the in-flame temperatures, the heat flux and the thermal efficiency was investigated and evaluated. Each parameter was measured and evaluated for three different burners: the burner with the staged gas, the burner with the staged air and the burner for low calorific fuels. Generally, after the addition of the inert gas into the noble fuel, the in-flame temperatures decreased. As a consequence, the NOx emissions decreased as well. The effects of carbon dioxide on the investigated combustion parameters were more substantial than the effects of nitrogen. Each measured parameter is strongly dependent on the burner geometry. The experiments revealed that in most cases the addition of the inert gas into the fuel influenced the flame length (flame shortened) and also more heat was transfered into the chamber's walls closer to the burner tile.

The theme of the diploma thesis is to analyze the use and prepare the business plan of establishing alternative fuel showroom cars. Showroom will focus on sales of new cars with full warranty that are primary equipped with alternative fuel engine. The idea of concentrating sales center of alternative fuel cars is unique, in the vast majority of cases sellers are becoming dealers of automobile manufacturers and their direct representatives. The sales center will be concentrated in the Prague region where the parent company has its placr of business. The theoretical part of the thesis is devoted to the characteristics of conventional and alternative fuels. In the practical part there is created a business plan of construction and operation alternative fuel cars showroom. The project is prepared on real numbers and will be used during implementation in practise.

The dissertation is dedicated to the utilization of alternative propellants in transport with concentration in biofuel. Firstly, the theoretical part is focused on the technical aspects of their utilization. In addition, fuel characteristics, conditions and options of their applications in diesel-powered vehicle engines are there characterized. The influence on production of exhaust emission is also mentioned and legislation is briefly summed up there. Secondly, the practical part contents the measurement of basic parameters to the classic-powered engine and the biofuel-powered engine in a tractor Zetor Forterra 9641. The whole measurement is carried out in vehicle laboratories in the Department of Technology and Automobile Transport of Mendel University in Brno. Moreover a detailed elaboration and the final evaluation of the measurement results are included in the second part of the dissertation.

In the literary part of the diploma thesis, a brief overview of the current state in the tractor design has been done, concentrating onto such elements that lead to lowering of fuel consumption. The practical part is based on the realized solution. The target of the measurement was to prove the influence of adjusting of the three-point hitch onto the output parameters of ploughing sets, consisting of the Zetor Forterra 140 HSX tractor and Kverneland 150 B mounted plough or Kverneland PN 100 semi-mounted plough. The essence of the measurement was gradual shortening of the upper linkage of the three-point hitch, whereas simultaneously with shortening of the linkage, the force on the linkage was rising. The force was measured by means of strain gauge Hotinger U2A. In case of the mounted plough it has been proved that shortening of the upper linkage causes rising of the force. That shifts part of the plough weight onto the rear wheels of the tractor, resulting in lower wheel slipping and lower fuel consumption.

This diploma thesis deals with the economy of the tractor sets of the tractor CASE IH Magnum 280 and the tractor CASE IHPuma 230 CVX EP. The economy is considered with the selected agricultural machines operating by the processes of ploughing and stubble- tillage. The ploughing was done with with the six-and seven- blade plough Kverneland PG 100. The stubble-tillage was done with the disc stubble- plough Diskomat 6. The technical parametres of the tractor engines were taken from DLG- Top Agrar Test Heft Nr. 11/2003 and from CNH CASE PUMA 230 CVX/ DLG 2010-268. The diploma thesis contains energy and efficiency parametres of the tractor sets. The results are based on the one-year observations. The obtained parametres are elaborated in the forms of tables and graphs. The measured figures were used to present the technical - economic analysis.

The work deals with optimizing the operation of spark ignition internal combustion engine on fuel E85. The theoretical part is devoted to the issue of biofuels in terms of production, distribution and use in internal combustion engines. The experimental part is devoted to the design and verification of the additional control unit (ADU) which solves the optimisation of operation unmodified engine on E85. The first part of the experiment is dedicated to the design and construction of ADU with aim to faultless operation of the engine on E85. The second part of the experiment was devoted to optimisation of engine operation in terms of fuel consumption using dynamic changes of the injectors opening time. Part of the experiments was an evaluation of emissions production and impact on the performance parameters of the engine. The final part of the experiment evaluates the achieved results at the various settings strategy of ADU and compares them with results during engine operation on prescribed fuel N95. By the dynamic change of the injector opening time were reached decrease in fuel consumption by about 5%, reduction in CO production by around 70%, approximately fourfold increase in the production of NOx emissions and about 50% decrease in production of particulate matters.

This doctoral dissertation thesis deals with rotary mowers, specifically with the issue of mulching. In the theoretical part the reader is being familiar with the technology of mulching and its importance. Further, the individual types of mulchers and its advantages and disadvantages are described. The literary analysis of energy demands of rotary mowers is stated. Further, the parameters influencing energy demands of the mulcher are also analyzed. The results of measurement of the energy demands of the mulcher with vertical axis of rotation are presented. The dependency of input power, specific energy consumption and fuel consumption on mass performance of the machine are created. Furthermore, the energy demands was determined, while mulcher was working continuously at the permanent grassland. The energy losses of the mulcher were also analyzed. The effect of modification of operational and constructional parameters on the energy demands and quality of work of the mulcher wit vertical axis of rotation is studied. From the constructional parameters the shape of working tool, especially cloth angle and rake angle of the tool, and shape of the cover of the mulcher workspace is modified. From the operational parameters the cutting speed and mass performance according to conditions is modified.