Made available in DSpace on 2015-05-08T14:59:57Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5488981 bytes, checksum: bc22a73599584c867e933138268f4187 (MD5) Previous issue date: 2014-06-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A large number of national companies has been using diesel gensets as an alternative to the electricity supplied by the local utility. Therefore, generators are used as an emergency power system or during peak hours. Peak hour in Brazil is between 5 to 10 p. m. As we know diesel engines contribute to the large increase in environmental pollution, since the diesel exhaust may contain fine particles associated with negative health effect, toxic air contaminants, as NOx and SOx. On the other hand, Natural gas is considered as a suitable choice rather than the use of diesel, because it possesses high calorific power, clean burning, and proper octane level for Otto cycle engine. The present work deals with the performance analysis of a Perkins engine turbocharged, diesel, model 1104C-44TA, converted into an Otto cycle engine to run on natural gas, also identifying the limiting factors of power in these types of engines. Giving the importance of the compression rate on the Diesel to Otto cycle conversion, the evaluation of the Perkins processed engine happened under the influence of three different rates: 7.6:1; 8.7:1 and 12.3:1. For each compressed rate, and stoichiometric mixture, the task was to choose the spark advance to guarantee best performances to the engine. All tests were performed with a hydraulic dynamometer. The results showed that, the best combination of those parameters are not sufficient to ensure the highest performance of a diesel converted engine. There was a consubstantial rise in temperature of the exhaust gases and on the turbine walls, due to the increase in the exhaust gases volume, compared to that of the burnt gases withdrawn from the original engine, impairing the efficiency and lifespan of the engine components. It was found, by energetic analysis, the compression ratio of 8.7:1, was the most efficient, among the other two, assuring the engine its best performance. As expected, at the compression rate of 7.6:1 the exhaust gases presented the highest temperatures. At compression ratio of 12.3:1 the gas emissions of the converted engine delivered highest NOx level and the lowest level of unburned hydrocarbons at the exhaust. Keywords: Diesel Turbocharged Engine. Diesel to Otto Cycle Conversion Process. Natural Gas. Performance. Energy Balance / Um grande número de empresas nacionais faz uso de grupos geradores a diesel como opção à eletricidade fornecida pela concessionária local. O emprego de grupos geradores é comum durante as horas de pico, que no Brasil, ocorrem entre as 17 e 22 h. Tais aparatos, juntamente com os motores veiculares a diesel têm contribuído para o grande aumento da poluição ambiental, uma vez que a queima deste combustível se faz com grande emissão de particulados, de NOx e de SOx. O gás natural é considerado uma alternativa ao uso do diesel por possuir um alto poder calorífico, queima limpa, e adequada octanagem para o ciclo Otto. O presente trabalho trata da análise de desempenho de um motor Perkins turboalimentado, a diesel, modelo 1104C-44TA, convertido para funcionar apenas com gás natural, identificando ainda, os fatores limitadores de potência nestes tipos de motores. Considerando a importância da taxa de compressão no processo de ottolização, o motor convertido foi avaliado sob a influência de três diferentes taxas: 7,6:1; 8,7:1 e 12,3:1. Para tanto, foram selecionados avanços de ignição que ao interagir com a mistura próxima da estequiométrica garantisse ao funcionamento do motor as melhores condições de desempenho, para cada taxa de compressão escolhida. Os ensaios foram feitos com o auxílio de um dinamômetro hidráulico e os resultados obtidos evidenciaram que, na prática, tais parâmetros não são suficientes para se assegurar os melhores desempenhos em um motor diesel ottolizado. Foi observado um aumento consubstancial na temperatura dos gases de exaustão e na turbina, em virtude da ampliação do volume dos gases de escapamento com relação àquele observado no motor original, com prejuízos para a eficiência e a própria vida útil do motor. Verificou-se, através das análises energéticas, que a taxa de compressão de 8,7:1 permitiu ao motor seu melhor desempenho, com relação à outras experimentadas. Como esperado, o motor operando na taxa de 7,6:1 produziu as mais elevadas temperaturas dos gases de exaustão. Com respeito às emissões gasosas, o motor convertido com taxa de compressão de 12,3:1 emitiu o maior nível de NOx e o menor nível de hidrocarbonetos não queimados

A masters thesis deals with the question of deisel engine boosting by rotary turbochargers. The objective of the thesis is to propose suitable turbocharger´s concept for defined diesel combustion engine with power of 430 [kW]. The air boosting pressure is controlled by exhaust gas flow through the turbine and different EGR regimes, which are considered in the basic and corrected calculations. The final turbocharger´s concept is proposed to satisfy the defined technical requirements. Next technical recommendations are briefly summarized in the thesis conclusion for following turbocharger´s concept application.

The aim of the master’s thesis is analysis of practical application limits of waste-gate TwinScroll turbocharger located in BMW X6 M vehicle by using DFSS (Design For Six Sigma) tools. The goal is to create a special measurement device for a measurement of waste gate leakage with chance of testing all sorts of characteristics having impact on key parameters of turbocharger.

The master’s thesis deals with the question of petrol engine boosting by rotary turbochargers. The objective of the thesis is to project suitable turbocharger for defined single-cylinder petrol engine. After selecting the suitable turbocharger type it will follow the construction of the computational model of the single-cylinder turbocharged petrol engine in the Lotus Engine Simulation software. In the computational model is boost pressure regulated by the turbine waste gate valve. The result will be the boost pressure values scheme for the highest possible torque so that the maximum combustion pressures will not exceed the value of 9,5 MPa. There are summarized findings and results in the conclusion of the thesis.

This diploma thesis is focused on solve of design solutions for piston for turbocharged version of Honda K20A engine, especially on reduce of side force acting on piston. There are mentioned methods and on their basis also design solutions for piston to reduce this force. There is also included kinematic and dynamic analysis for each solution and as well their FEM analysis for testing the suitability of these solutions.

Heat transfer plays an important role in affecting an on-engine turbocharger performance. However, it is normally not taken into account for turbocharged engine simulations. Generally, an engine simulation based on one-dimensional gas dynamics uses turbocharger performance maps which are measured without quantifying and qualifying the heat transfer, regardless of the fact that they are measured on the hot-flow or cold-flow gas-stand. Since heat transfer situations vary for on-engine turbochargers, the maps have to be shifted and corrected in the 1-D engine simulation, which mass and efficiency multipliers usually do for both the turbine and the compressor. The multipliers change the maps and are often different for every load point. Particularly, the efficiency multiplier is different for every heat transfer situation on the turbocharger. The heat transfer leads to a deviation from turbocharger performance maps, and increased complexity of the turbocharged engine simulation. Turbochargers operate under different heat transfer situations while they are installed on the engines. The main objectives of this thesis are: heat transfer modeling of a turbocharger to quantify and qualify heat transfer mechanisms, improving turbocharged engine simulation by including heat transfer in the turbocharger, assessing the use of two different turbocharger performance maps concerning the heat transfer situation (cold-measured and hot-measured turbocharger performance maps) in the simulation of a measured turbocharged engine, prediction of turbocharger walls’ temperatures and their effects on the turbocharger performance on different heat transfer situations. Experimental investigation has been performed on a water-oil-cooled turbocharger, which was installed on a 2-liter GDI engine for different load points of the engine and different heat transfer situations on the turbocharger by using insulators, an extra cooling fan, radiation shields and water-cooling settings. In addition, several thermocouples have been used on accessible surfaces of the turbocharger to calculate external heat transfers. Based on the heat transfer analysis of the turbocharger, the internal heat transfer from the bearing housing to the compressor significantly affects the compressor. However, the internal heat transfer from the turbine to the bearing housing and the external heat transfer of the turbine housing mainly influence the turbine. The external heat transfers of the compressor housing and the bearing housing, and the frictional power do not play an important role in the heat transfer analysis of the turbocharger. The effect of the extra cooling fan on the energy balance of the turbocharger is significant. However, the effect of the water is more significant on the external heat transfer of the bearing housing and the internal heat transfer from the bearing housing to the compressor. It seems the radiation shield between the turbine and the compressor has no significant effect on the energy balance of the turbocharger. The present study shows that the heat transfer in the turbocharger is very crucial to take into account in the engine simulations. This improves simulation predictability in terms of getting the compressor efficiency multiplier equal to one and turbine efficiency multiplier closer to one, and achieving turbine outlet temperature close to the measurement. Moreover, the compressor outlet temperature becomes equal to the measurement without correcting the map. The heat transfer situation during the measurement of the turbocharger performance influences the amount of simulated heat flow to the compressor. The heat transfer situation may be defined by the turbine inlet temperature, oil heat flux and water heat flux. However, the heat transfer situation on the turbine makes a difference on the required turbine efficiency multiplier, rather than the amount of turbine heat flow. It seems the turbine heat flow is a stronger function of available energy into the turbine. Of great interest is the fact that different heat situations on the turbocharger do not considerably influence the pressure ratio of the compressor. The turbine and compressor efficiencies are the most important parameters that are affected by that. The component temperatures of the turbocharger influence the working fluid temperatures. Additionally, the turbocharger wall temperatures are predictable from the experiment. This prediction enables increased precision in engine simulations for future works in transient operations. / QC 20120504

Táto diplomová práca je zameraná na preukazovanie vplyvov rôznych architektúr spätnej recirkulácie spalín na preplňované benzínové motory. Simulácie boli vytvorené v termodynamickom simulačnom programme GT-Power. Práca začína porovnávaním vplyvov spätnej recirkulácie na ustálené stavy motora, najmä z hľadiska spotreby, ktoré sú následne implementované do tranzientných modelov, simulujúc emisné testovacie cykly. Na konci práce sa venujem vplyvom spätnej recirkulácie na funkciu oxidačno-redukčného katalyzátora a na funkciu turbodúchadla.