When designing a new fuel management system for a spark ignition engine the amount of air that is fed to the cylinders is highly important. A tool that is being used to improve the performance and reduce emission levels is engine modeling were a fuel management system can be tested and designed in a computer environment thus saving valuable setup time in an engine test cell. One important part of the modeling is the throttle which regulates the air. The current isentropic model has been investigated in this report. A throttle body and intake manifold has been simulated using Computational Fluid Dynamics (CFD) and the influence of surface heating and surface wall roughness has been calculated. A method to calculate the effective flow area has been constructed and tested by simulating at two different throttle plate angles and several pressure ratios across the throttle plate. The results show that both surface wall roughness and wall heating will reduce the mass flow rate compared to a smooth and adiabatic wall respectively. The reduction is both dependent on pressure ratio and throttle plate angle. The effective area has showed to follow the same behaviour as the mass flow rate for the larger simulated throttle plate angle 31 degrees, i.e. an increase as the pressure drop over the throttle plate becomes larger. At the smaller throttle plate angle 21 degrees, the behaviour is completely different and a reduction of the effective area can be seen for the highest pressure drop where a increase is expected. / När ett nytt bränslesystem ska designas till en bensinmotor är det viktigt att veta hur stor mängd luft som hamnar i cylindrarna. Ett verktyg som är på frammarsch för att förbättra prestanda och minska emissioner är modellbaserad simulering. Med hjälp av detta kan ett bränslesystem designas och testas i datormiljö och därigenom spara dyrbar tid som annars måste tillbringas i en motortestcell. En viktig del av denna modellering är spjället eller trotteln vilken reglerar luften. I denna rapport har studier gjort på den nuvarande isentropiska modellen. Ett spjällhus och insugsgrenrör har simulerats med hjälp av Computational Fluid Dynamics (CFD) och påverkan av värme samt ytjämnhet på väggen har beräknats. En metod att beräkna den effektiva genomströmmade arean har konstruerats och testats vid två olika spjällvinklar samt flertalet tryckkvoter över spjället. Resultaten visar att både en uppvärmd vägg och en vägg med skrovlighet kommer att minska massflödet jämfört med en adiabatisk respektive en slät vägg. Minskningen har både spjällvinkel samt tryckkvots beroende. Den effektiva genomströmmade arean har visats sig följa samma beteende som massflödet vid den större simulerade spjällvinkeln 31 grader, det vill säga öka med ökat tryckfall över spjället. Vid den mindre vinkeln 21 grader, är beteendet helt annorlunda jämfört med massflödet och en minskning av den effektiva arean kan ses vid det största tryckfallet där en ökning förväntades.

Darbo apimtis yra 51 puslapių, jame yra 23 paveikslėliai. Literatūros aprašą sudaro 36 literatūros šaltiniai. Pagrindinis tiriamojo darbo tikslas – išanalizuoti hidraulinio cilindro stūmoklio greičio charakteristikų priklausomybę, keičiant hidraulinio cilindro apkrovą bei esant pastoviam siurblio slėgiui. Magistrantūros baigiamąjį darbą sudaro trys dalys: literatūros apžvalga, teoriniai tyrimai ir eksperimentiniai tyrimai. Literatūros apžvalgoje pateikiama droselinės hidraulinių sistemų reguliavimo sistemos, automatizuotos sistemos bei jų sandara. Teoriniuose tyrimuose yra išnagrinėtas droselinis valdymas ir reguliavimas, jo veikimo principai, naudingumo koeficientai bei galios balansas. Eksperimentiniuose tyrimuose yra išnagrinėta hidraulinio cilindro stūmoklio greičio charakteristikų priklausomybė nuo hidraulinio cilindro stūmoklio judėjimo greičio bei apkrovos. Sumontavus specialią hidraulinę sistemą atlikti hidraulinio cilindro stūmoklio greičio charakteristikų tyrimai. / Volume of work is 51 pages and contains 23 pictures. References inventory consists of 36 literary sources. The main aim of the investigation - to analyze the hydraulic cylinder shaft speed characteristics of dependency, changing the working pressure of hydraulic system and droseliavimo character. Master's thesis consists of three parts: an overview of sources of information, an overview of theoretical studies and experimental studies. Review of information sources describe butterfly hydraulic systems framework, addresses the butterfly speed control characteristics. The work purpose – to find out features of throttle adjustment of speed of movement the piston of hydraulic system of the big capacity. Experimental researches have been carried out with earlier described device. In the hydraulic cylinder design changes have been executed, the sizes and throttle place by means of theoretical throttle characteristic ADR = f(h) are changed. For reduction of turn time of a working platform it was necessary to increase pressure in hydraulic systems with 60 to 70 bar. Pressure increase has allowed piston to increase speed of movement. These changes have specified on a smooth stop of a working platform a problem. Time of turn of a working platform has decreased till 1,31 seconds. The piston pressure in the braking chamber is equal in last phase of work 48 bar, it tells about prevention of blow the piston about the hydraulic cylinder.

A study has been conducted into the causes of cycle by cycle variations in combustion within a spark ignition engine, the best measured engine parameter to use for its characterization, and the effects that: ignition timing, equivalence ratio, fuel type, throttle position and knock, have upon it. A Ricardo E6 single cylinder variable compression ratio research engine was instrumented to allow measurement of: cylinder pressure, temperatures, speed, load, fuel flow and air flow. The engine was also fitted with an optical slice that allowed optical access to the combustion chamber and enabled measurement of the early flame speed (up to 10 mm from spark plug gap) using a laser schileren system. Cylinder pressure data were collected on a dedicated HP1000 computer for every degree of crank angle rotation for up to 300 successive cycles. A phenomenological model was developed for turbulent combustion that split the combustion process into three phases: early laminar burn, turbulent combustion, and final burn. The model allowed the study of the physical phenomena occurring within the combustion chamber and enabled insights to be gained into their effects on combustion and cyclic variations. The study showed: The variation in mixture strength has a far greater effect on the average and Coefficient of Variation (COV) values of all the combustion performance parameters, than does changing the fuel type. Cycle by cycle variations in combustion are best characterized by COV of imep. The onset of knock has no discernible effect on the COVs of the measured parameters. The part throttle results show higher COVs than at Wide Open Throttle (WOT) due to slower burn, supporting the theory that faster initial flame speeds reduce cyclic variations. The combustion model was used to support the hypothesis that cycle by cycle variations are caused by movement of the flame kernel by turbulence within the combustion chamber.

The objective of the work was to develop a basic control system for an advancedexperimental engine from scratch. The engine this work revolves around is a Saabvariable compression engine.A new control system is developed based on the naked engine, stripped of theoriginal control system. Experiments form the basis that the control system isbuilt upon. Controllers for throttles, intake manifold pressure for pressures lessthan ambient pressure and exhaust gas oxygen ratio are developed and validated.They were found to be satisfactory. The lambda controller is tested with severalparameter sets, and the best set is picked to be implemented in the engine. Modelsnecessary for the development and validation of the controllers are developed.These models include models for the volumetric efficiency, the pressure dynamicsof the intake manifold, the fuel injectors and wall wetting.

The high demands on low fuel consumption and low emissions on the combustion engines of both today, and the future, is highly dependent on advanced control systems in order to fulfill these demands. The control systems and strategies are based on models which describe the physical system. The more accuratly the models describe the real world system, the more accurate the control will be, leading to better fuel economy and lower emissions. This master's thesis investigates and improves the mass flow model used for a compressible restriction, such as over the throttle valve, EGR valve, or the wastegate valve, for example. The standard model is evaluated and an improvement is proposed which does not assume isentropic flow. This seems to explain the deviation from the isentropic Psi-function shown in earlier research such as (Andersson:2005). Furthermore a throttle valve is analyzed in ANSYS in order to show the generation of entropy. The presence of pressure pulsations in a combustion engine is also evaluated, especially how they effect the otherwise assumed steady flow model. It is tested if a mean value pressure is sufficient or if one needs to take the pulsations in to account, and the result shows that a mean pressure is sufficient, at least for the throttle when typical intake manifold pulsations is present. A dynamic flow model is also derived which can be useful for pressure ratios close to one. The dynamic flow model is based on the standard equation but with an extra dynamic term, however it is not implemented and tested due to complexity and time limitation. The proposed new non-isentropic flow model has proven promising and can hopefully lead to lower emissions and better fuel economy.

Hybrid motors that employ non-toxic, non-explosive components with a liquid oxidizer and a solid hydrocarbon fuel grain have inherently safe operating characteristics. The inherent safety of hybrid rocket motors offers the potential to greatly reduce overall operating costs. Another key advantage of hybrid rocket motors is the potential for in-flight shutdown, restart, and throttle by controlling the pressure drop between the oxidizer tank and the injector. This research designed, developed, and ground tested a closed-loop throttle controller for a hybrid rocket motor using nitrous oxide and hydroxyl-terminated polybutadiene as propellants. The research simultaneously developed closed-loop throttle algorithms and lab scale motor hardware to evaluate the fidelity of the throttle simulations and algorithms. Initial open-loop motor tests were performed to better classify system parameters and to validate motor performance values. Deep-throttle open-loop tests evaluated limits of stable thrust that can be achieved on the test hardware. Open-loop tests demonstrated the ability to throttle the motor to less than 10% of maximum thrust with little reduction in effective specific impulse and acoustical stability. Following the open-loop development, closed-loop, hardware-in-the-loop tests were performed. The closed-loop controller successfully tracked prescribed step and ramp command profiles with a high degree of fidelity. Steady-state accuracy was greatly improved over uncontrolled thrust.

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Dagens behov för energieffektivisering ställer höga krav på industrisektorn som anses vara den största energikonsumenten. Holmen AB är verksam inom massa- och pappersindustrin som är en energiintensiv bransch där sådana stora energianvändare som pumpapplikationer spelar en nyckelroll i produktionen. Denna studie genomfördes för att hjälpa företaget att undersöka vilka energi- och kostnadsbesparingar som kan förväntas om det befintliga pumpreglersättet ändras. Syftet med arbetet var att ta fram en metod för uppskattning av pumpenergiförbrukning, som skulle producera ett underlag för en jämförelseanalys av energiförbrukningen vid olika reglersätt. Studien fokuseras mest på centrifugalpumpar, som dominerar i industriell miljö på grund av sin robusta konstruktion, höga effektivitet och relativt låga behov för underhåll. Men det tillvägagångssätt som har använts i studien kan användas för bedömning av olika typer av pumpar och reglersätt eftersom det byggs på de grundläggande fluidmekanikslagarna. Tidigt i arbetet identifierades de viktiga parametrar som mest påverkar energiförbrukning i centrifugalpumpar och som krävs i beräkningar. Olika reglersätt diskuterades utifrån den befintliga litteraturen och forskningen. Uppskattning av energiförbrukning och energikostnader utfördes för två olika reglersätt, strypreglering och frekvensreglering. I arbetets sista skede jämfördes resultaten för de två reglersätten för att avgöra om det finns en potential för energi- och kostnadsbesparingar vid byte från strypreglering till frekvensreglering. Studiens resultat visar att övergång till frekvensreglering kommer att medföra energibesparingar och som följd besparingar i årliga driftkostnader samt LCC-kostnader. Storleken på besparingarna beror på minskning i varvtalet. Frekvensregleringen är mest lönsam då det önskade flödet skiljer sig mycket från det nominella flödet i systemet, men eventuell försämring av motor- och pumpverkningsgrad måste tas i beaktande. En mer utförlig analys av energiförbrukning vid olika flöden och olika typer av medier rekommenderas att utföras med användning av praktiskt uppmätta effektförbrukningsvärden. / Today's need for energy efficiency places high demands on the industrial sector, which is considered to be the largest energy consumer. Holmen AB is a pulp and paper producer. Pulp and paper production is an energy-intensive branch where pump applications consume large amounts of energy while playing a crucial role in the production process. This study was conducted to help the company investigate what energy and cost savings can be expected if the existing pump control method is changed. The purpose of the study was to develop an approach for estimating pump energy consumption, which would produce a basis for comparative analysis of energy consumption for different control methods. The study focuses mainly on centrifugal pumps, which dominate the industrial environment due to their robust construction, high efficiency, and relatively low maintenance needs. However, this study's approach can be used to assess different types of pumps and control modes as it is based on the fundamental fluid mechanics laws. At the beginning of the study, the key parameters that affect energy consumption in centrifugal pumps were identified to be later used in calculations. Pump control methods were discussed based on the existing literature and research. Estimation of energy consumption and costs was performed for two different control methods, throttle control, and frequency control. In the last stage of the study, two control methods were compared based on the energy consumption calculation to determine whether there is a potential for energy and cost savings when switching from throttle control to frequency control. The results show that usage of frequency control would lead to energy savings and, therefore, to savings in annual operating costs and LCC costs. The amount of the savings depends on the reduction in the rotational speed of the motor. The frequency control is most advantageous when there is a significant difference between the desired flow and the nominal flow in the system. But the potential reduction of motor and pump efficiency must be taken into consideration. A more detailed analysis of energy consumption for different flows and different types of pulp is recommended, with practically measured energy consumption values.

A válvula borboleta é o atuador principal do sistema de admissão de ar no motor a combustão interna ciclo Otto (MCI), determinando a massa de ar admitida para o sistema de gerenciamento eletrônico do motor (ECU) realizar os cálculos de controle da injeção eletrônica de combustível, e o momento de lançamento da centelha para o sistema de ignição eletrônica, atuando também no regime de funcionamento do MCI. Este trabalho explora o controle da válvula borboleta eletrônica automotiva, onde foram estudados diversos modelos de controle para a válvula borboleta. O controle visa responder a ECU que demanda um determinado ângulo de abertura da válvula borboleta, para o melhor funcionamento e gestão do MCI para cada região de operação do motor, sendo este ângulo de abertura determinado pela própria ECU. O principal objetivo do trabalho é buscar um melhor desempenho do controle da válvula borboleta, para responder com exatidão ao comando da ECU e, consequentemente, um desempenho ótimo do motor de combustão interna. Adicionalmente, o trabalho promove avanços parciais para o desenvolvimento de uma unidade eletrônica de gerenciamento do motor. / The throttle is the main actuator of the air intake system in an internal combustion engine Otto cycle (MCI), determining the mass of air admitted to the system of electronic engine management (ECU) in the calculations of the electronic injection control fuel, and the timing of the spark to launch the electronic ignition system, also working in the regime of operation of the MCI. This work explores the control of automotive electronic throttle valve, where many control for throttle valve was studied. The control ECU aims to answer that demand a certain opening angle of the throttle valve, to improve the functioning and management of MCI for each region of operation of the engine, and this opening angle determined by the ECU itself. The main objective is to seek a better control performance throttle valve to respond accurately to the command of the ECU and hence optimum performance of the internal combustion engine. In addition, the work promotes partial advances in the development of an electronic engine management unit.

A válvula borboleta é o atuador principal do sistema de admissão de ar no motor a combustão interna ciclo Otto (MCI), determinando a massa de ar admitida para o sistema de gerenciamento eletrônico do motor (ECU) realizar os cálculos de controle da injeção eletrônica de combustível, e o momento de lançamento da centelha para o sistema de ignição eletrônica, atuando também no regime de funcionamento do MCI. Este trabalho explora o controle da válvula borboleta eletrônica automotiva, onde foram estudados diversos modelos de controle para a válvula borboleta. O controle visa responder a ECU que demanda um determinado ângulo de abertura da válvula borboleta, para o melhor funcionamento e gestão do MCI para cada região de operação do motor, sendo este ângulo de abertura determinado pela própria ECU. O principal objetivo do trabalho é buscar um melhor desempenho do controle da válvula borboleta, para responder com exatidão ao comando da ECU e, consequentemente, um desempenho ótimo do motor de combustão interna. Adicionalmente, o trabalho promove avanços parciais para o desenvolvimento de uma unidade eletrônica de gerenciamento do motor. / The throttle is the main actuator of the air intake system in an internal combustion engine Otto cycle (MCI), determining the mass of air admitted to the system of electronic engine management (ECU) in the calculations of the electronic injection control fuel, and the timing of the spark to launch the electronic ignition system, also working in the regime of operation of the MCI. This work explores the control of automotive electronic throttle valve, where many control for throttle valve was studied. The control ECU aims to answer that demand a certain opening angle of the throttle valve, to improve the functioning and management of MCI for each region of operation of the engine, and this opening angle determined by the ECU itself. The main objective is to seek a better control performance throttle valve to respond accurately to the command of the ECU and hence optimum performance of the internal combustion engine. In addition, the work promotes partial advances in the development of an electronic engine management unit.