Dissertations / Theses on the topic 'Split injection'

Split-injection is applied in automotive diesel engines in order to control heat release and pollution production. Injecting fuel prior to the main fuel injection, known as pilot injection, increases premixing and tends to reduce NOx emission. Injecting a portion of the fuel after the main injection has potential for reducing particulate emissions. In order to meet increasingly stringent emission and fuel consumption regulations, modern automotive diesel injectors have been developed with the capacity to deliver of the order of ten separate injection pulses during a single engine stroke. Simulation methods for split-injection engines are required in order to develop more advanced injection strategies with two or more separate fuel-injections. A range of additional combustion applications involve mixing and combustion between multiple streams such as Exhaust Gas Recirculation (EGR) and dual fuel injections. Modelling for the turbulent combustion interactions in multi-stream problems is developed in this thesis in the context of Conditional Moment Closure (CMC) methods. The CMC approach provides modelling of chemical processes in turbulent flows by linking composition fluctuations to the variation of a small number of conditioning variables such as mixture fraction. In order to achieve good accuracy, the conditioning variables must be chosen to minimise compositional fluctuations around the conditional mean. Split-injection diesel engine operation results in complex combustion behaviour in which a single conditioning variable may be insufficient. However multiple-conditioned moment closures, or even double conditional moment closures (DCMC) have not been exploited previously. The objective of this study is to identify the most appropriate conditioning variables for modelling of split-injection diesel engines and to formulate, validate and demonstrate a practical implementation of the DCMC approach for engine-relevant simulations. The thesis begins by developing a new formulation of the DCMC approach that is applicable to a general set of non-conserved conditioning variables, and a set of numerical solution approaches is demonstrated and verified. The choice of conditioning variables is then investigated through direct numerical simulations of autoignition in a turbulent flow with up to three separate fuel injections. In the case with a single injection, fluctuations around the mixture fraction-conditioned mean arise due to variation in mixture fraction dissipation rate affecting the progress of ignition differently at different points in space. In cases with multiple injections, the repeated addition of unreacted fuel also adds to fluctuations around the conditional mean. The high level of conditional fluctuations leads to large errors when employing singly-conditioned first-order conditional moment closure. Alternative doubly conditional moment closure approaches are tested using a priori and a posteriori analyses. Single conditioned first order closure gives extremely poor agreement with the DNS, and the study indicates that double conditioning on mixture fraction and progress variables, such as the sensible enthalpy, outperforms double conditioning on multiple mixture fractions. The feasibility of the zero-dimensional DCMC approach for practical predictive design calculations is then assessed further through simulations of n-heptane spray ignition in constant volume research vessels with single or multiple injections. The experimental flows are simulated by coupling the zero-dimensional first order double conditional moment closure (0D-DCMC) with a commercial CFD code and an efficient Operator Splitting solution method is demonstrated. The predictions show the same trends as the experimental observations, however ignition delays and lift off lengths agree with the measurements only approximately. Reasons for the discrepancies include the uncertainty in the chemical modelling as well as in the ambient temperature surrounding the spray in the experiments. The modelling of conditional cross-scalar dissipation rate is also found to have a significant influence on the flame evolution, with the limiting cases of modelling corresponding to zero correlation or unity correlation between mixture fraction and progress variable giving unrealistic predictions. Conditional cross-dissipation rate modelling corresponding to negative unity correlation gives reasonable predictions, and an argument for why negative mixture fraction-progress variable correlation is expected to be dominant in autoignitive lifted jet flames involving multiple fuel injections is presented. Other aspects of modelling uncertainty with regard to conditional dissipation rates, presumed joint mixture fraction-progress variable probability density functions and first order source term closures will also contribute to the model error, and further development of models suitable for spray autoignition cases would be beneficial. In comparison with the established three-dimensional singly-conditioned moment closure (3D-CMC), the 0D-DCMC model is a promising approach which is expected to be substantially faster than the 3D-CMC approach in most problems of engineering interest. Not withstanding the imperfect predictions, the ability of the zero-dimensional DCMC to describe the whole split-injection process and to provide new insight into the mechanisms involved is encouraging: this implies that only a few DCMC control volumes may be needed in order to model a wide range of flows involving very complex physics, of which split-injection is just one example, and the DCMC approach is therefore recommended for further development.

This study investigates the effects of a split injection strategy on combustion performance and exhaust emissions in a high speed direct injection optical diesel engine. The investigation is focused on the effects of injection timing, quantity, and the dwell angle between the injections using commercially available diesel fuel. Three different split injection strategies including 50:50, 30:70, and 70:30 have been investigated. Additionally, the effect of total injected fuel quantity using total fuel quantities of 10 mm3 and 20 mm3 has been investigated. Moreover, the effect of variable and fixed dwell angle in split injections has been examined for five different values between 5o CA and 25o CA in the case of variable and 10o CA for the fixed dwell timing. The last parameter investigated was the injection timing, nine injection timings have been tested for each of the strategies. A Ricardo Hydra single cylinder optical engine running at 1500 rpm was used in this investigation. Conventional methods such as direct in-cylinder pressure measurements and heat release rate analysis have been employed. In addition, optical techniques such as high speed video imaging and two-colour have been applied, aimed at in depth analysis of the effects of the aforementioned parameters on engine performance and emissions. Furthermore, a significant amount of effort was devoted to the development and application of the Laser Induced Excipex Fluorescence (LIEF) technique so that simultaneous fuel liquid and fuel vapour distribution could be visualised. This investigation concludes that split injection strategies have the potential to reduce diesel exhaust emissions while maintaining a good level of fuel economy, provided that injection timings and the dwell angle between injections are appropriately selected. Further investigations are required in order to examine the effect of split injection under different engine operating conditions and speeds. In addition, the effect of alternative fuels must be considered. Moreover, the application of LIEF technique for quantitative fuel vapour concentration measurement should be considered through further optimisation of the LIEF system and careful calibration experiments.

Over the last decade, the diesel engine has made dramatic progress in its performance and market penetration. However, in order to meet future emissions legislations, Nitrogen Oxide (NOx) and particulate matter (PM) emissions will need to be reduced simultaneously. Nowadays researchers are focused on different combustion modes like homogeneous charge compression ignition (HCCI) combustion and premixed charge compression ignition (PCCI) which have a great potential for both low soot and low NOx. In order to achieve these combustion modes, different injection strategies have been investigated. This study investigates the effects of split injection strategies with high levels of Exhaust Gas Recirculation (EGR) on combustion performance and emissions in a high speed direct injection optical diesel engine. The investigation is focused on the effects of split injections at different injection pressures, injection timings and dwell angles using base diesel and biodiesel fuels. The effect of fuel properties has been also investigated as an attempt to reduce regulated exhaust emissions in diesel engines. Performance, emissions and combustion characteristics have been examined for two different biodiesel fuels, namely BTL 50 and BTL 46. A Ricardo Hydra single cylinder optical engine was used in which conventional experimental methods like cylinder pressure data, heat release analysis and exhaust emissions analysis were applied. Optical techniques like direct spray and combustion visualization were applied by means of a high speed imaging system with a copper vapour laser illumination system. A high-speed two-colour system has been developed and implemented to obtain in-cylinder diesel combustion temperature and soot measurements to gain better understanding of the mixture formation and combustion processes. This investigation concludes that the split injection strategies show potential to achieve low emissions combustion.

CAI combustion and the factors affecting it were intensively investigated in a single cylinder, air-assisted gasoline direct injection engine. CAI was achieved by means of residual gas trapping by utilising low-lift short duration camshafts and early closing of the exhaust valves. The effects of EVC (Exhaust Valve Closure) and IVO (Inlet Valve opening) timings, spark timing, single and split injection timings, coolant temperature, compression ratio, cam lift and duration on exhaust emissions and CAI operation were investigated experimentally. Engine speed throughout the course of the experiments, was varied from 1200rpm to 2400rpm and the air/fuel ratio was altered from stoichiometric to the misfire limit. The results show that the EVC timing, compression ratio, cam lift and duration had significant influences on CAI combustion and emissions. Early EVC when combined with higher compression ratio and higher cam lift, enhance CAI combustion operation and stability. IVO timing had minor effect on CAI combustion while spark timing hardly affects CAI operation as soon as fully-developed CAI conditions were established. Coolant temperature was revealed to have substantial impact on CAI combustion when the coolant temperature was below 65C. The results also show the importance of injection timing. Early injection gave faster and more stable combustion, less HC and CO emissions, but more prone to knocking combustion and higher NOx emissions. Furthermore, CAI operation range could considerably be extended with injection during the recompression process. Late injection led to slower and unstable combustion, higher HC and CO emissions but lower combustion noise and NOx emissions. Split injection gave even further extension of CAI range in both stoichiometric and lean mixture operations. All the above clearly suggest, that optimising injection timing and using split injection is an effective way to control and extend CAI operation in a direct injection gasoline engine.

Diesel Engine has been the most powerful and relevant source of power in the automobile industryfor decades due to their excellent performance, efficiency and power. On the contrary, there arenumerous environmental issues of the diesel engines hampering the environment. It has been agreat challenge for the researchers and scientists to minimize these issues. In the recent years, severalstrategies have been introduced to eradicate the emissions of the diesel engines. Among them,Partially Premixed Combustion (PPC) is one of the most emerging and reliable strategies. PPC is acompression ignited combustion process in which ignition delay is controlled. PPC is intended toendow with better combustion with low soot and NOx emission.The engine used in the present study is a single-cylinder research engine, installed in Aalto UniversityInternal Combustion Engine Laboratory with the bore diameter of 200 mm. The thesis presentsthe validation of the measurement data with the simulated cases followed by the study of the sprayimpingement and fuel vapor mixing in PPC mode for different injection timing. A detailed study ofthe correlation of early injection with the fuel vapor distribution and wall impingement has beenmade.The simulations are carried out with the commercial CFD software STAR CD. Different injectionparameters have been considered and taken into an account to lower the wall impingement and toproduce better air-fuel mixing with the purpose of good combustion and reduction of the emissions.The result of the penetration length of the spray and the fuel vapor distribution for different earlyinjection cases have been illustrated in the study. Comparisons of different thermodynamic propertiesand spray analysis for different injection timing have been very clearly illustrated to get insightof effect of early injection. The parameters like injection timing, injection period, injection pressure,inclusion angle of the spray have an influence the combustion process in PPC mode. Extensivestudy has been made for each of these parameters to better understand their effects in the combustionprocess. Different split injection profiles have been implemented for the study of better fuelvapor distribution in the combustion chamber.The final part of the thesis includes the study of the combustion and implementation of EGR tocontrol the temperature so as to get more prolonged ignition delay to accompany the PPC strategyfor standard piston top and deep bowl piston top. With the injection optimization and implementationof EGR, NOx has been reduced by around 44%, CO by 60% and Soot by 66% in the standardpiston top. The piston optimization resulted in more promising result with 58% reduction in NOx,55% reduction in CO and 67% reduction in Soot. In both cases the percentage of fuel burnt wasincreased by around 8%.

The thesis presents investigations of advanced combustion strategies in a modern V6 diesel engine fuelled with mineral diesel and Tallow Methyl Ester (TME)-diesel blends, in order to meet future emissions legislation. One of the main objectives of this research is to improve fuel consumption whilst minimising engine emissions through the combined effects of injection strategy (fuel injection pressure, dwell period, pilot fuel quantity) and cooled Exhaust Gas Recirculation (EGR) on a modern V6 common rail direct injection diesel engine. In the case of using EGR (49–52%) at 1500 rpm and 10% of engine peak torque, by increasing the fuel injection pressure from 300 to 800 bar, engine thermal efficiency increased from 16.5 to 19.1% and 17.1 to 19.7%, BSFC decreased by 13.5% and 13.2%, smoke level decreased by 74.3% and 70.1% and NOx emissions increased by 69.6% and 68.0%, respectively for a short (5 CAD) and a long (40 CAD) dwell period. In addition, the study of a variation of pilot fuel quantities (0.8–3.0 mg/stroke) with a fixed dwell period (5 CAD) at two different fuel injection pressures (250 bar and 800 bar) shows that the smaller pilot quantity with the higher fuel injection pressure can be considered as an enhanced strategy to control engine performance and emissions simultaneously. Therefore, the combination of higher injection pressure, longer dwell, smaller pilot quantity and the use of EGR could potentially improve fuel consumption and minimise engine emissions. The use of TME-diesel blends results in lower engine thermal efficiency and higher fuel consumption and NOx emissions. In the case of 1500 rpm and 25% of engine peak torque, the combustion of TME10 and TME30 reduced the engine thermal efficiency from iii 35.3 to 33.7% and 35.3 to 33.2% and increased the BSFC by 4.9% and 6.5%, respectively. At the same engine condition, the combustion of TME-diesel blends increased NOx emissions by 1.8% and 10.0% and reduced CO by 0.9% and 1.8%, THCs by 18.0% and 23.9 %, smoke by 30% and 51.7% for TME10 and TME30 respectively. However, the engine thermal efficiency, BSFC and NOx emissions could be improved with the application of the combined effect of injection strategy (fuel injection pressure, dwell period, pilot fuel quantity) and EGR as shown in the first phase of this study.

Political, environmental and marketing factors mean there is a global requirement to produce vehicles with improved fuel economy and reduced emissions. This thesis shows that the gasoline direct injection (GDI) engine will continue to form a significant portion of the automotive propulsion market in the short to medium term. However, to reach future targets continuous development and optimisation of these engines is essential. The introduction to this thesis discusses the role some of the key aspects of GDI engine design have on overall engine efficiency. The fuel spray is shown to be a key contributor to this, as it is a primary driver in the fuel/air mixing process, and therefore intrinsically linked to the combustion efficiency.

Diesel engine emissions of oxides of nitrogen and particulate matter can be reduced simultaneously through the use of high levels of exhaust gas recirculation (EGR) to achieve low temperature combustion (LTC). Although the potential benefits of diesel LTC are clear, the main challenges to its practical implementation are the requirement of EGR levels that can exceed 60%, high fuel consumption, and high unburned hydrocarbon and carbon monoxide emissions. These limit the application of LTC to medium loads. In order to implement the LTC strategy in a passenger vehicle engine, a transition to conventional diesel operation is required to satisfy the expected high load demands on the engine. The investigation presented in this thesis was therefore aimed at improving the viability of the high-EGR LTC strategy for steady-state and transient operation. An experimental investigation was carried out on a single cylinder high-speed direct injection diesel engine. This thesis presents research on engine in-cylinder performance and engine-out gaseous and particulate emissions at operating conditions (i.e. EGR rate, intake pressure, fuel quantity, injection pressure) likely to be encountered by an engine during transient and steady-state operation. At selected operating points, further investigation in terms of in-cylinder spray and combustion visualization, flame temperature and soot concentration measurements provided deeper insight into the combustion and emissions phenomena. Increased intake pressure at single injection high-EGR LTC operation was investigated as a strategy to reduce the emissions of partial combustion by-products and to improve fuel economy. The higher intake pressure, although effective in reducing partial combustion by-products emissions and improving fuel economy, increased the EGR requirement to achieve LTC. A split fuel injection strategy with advanced injection timing on the other hand was effective in reducing the EGR requirement for LTC from 62% with single injection to 52% with split injections at 120 kPa (absolute) intake pressure. Unburned hydrocarbon emissions and fuel economy were particularly sensitive to intake oxygen mass fraction, and injection and dwell timings with the split injection strategy. In-cylinder soot formation and oxidation mechanisms with the split injection strategy were found to be significantly different from the single injection high-EGR LTC case. Transient simulation of an engine during combustion mode transition identified engine operating parameters on a cycle-by-cycle basis. Steady-state investigation of these test conditions provided significant insight into the combustion conditions and their effect on emissions and performance. The results from this thesis demonstrated the importance of optimizing both the air handling system performance and the fuel injection system during engine transients. The increased emissions and impaired performance due to slow response of the EGR and turbocharger systems during transitions to and from LTC modes can in part be mitigated through split injections optimized for the specific transient point. This provides a clear direction for engine developers to pursue in optimizing engine calibration when running with LTC-conventional diesel dual-mode strategies.

Les technologies mémoires 1.5Tr proposent des améliorations non négligeables en termes de performance et de fiabilité pour les microcontrôleurs visant les marchés florissants de l’automobile et de l’internet des objets. Dans cette thèse, une mémoire unique en son genre et innovante basé sur un transistor de sélection vertical et enterré et appelé « embedded Select Trench Memory » (eSTM) est présenté. Après un état de l'art concis, un chapitre est consacré à la présentation d'outils pour améliorer la caractérisation et l'analyse du transistor mémoire unitaire ou intégré dans une macrocell. Plus précisément des outils pour analyser les bitmaps des macrocell sont proposés afin d’évaluer et d'optimiser la fiabilité et la variabilité de la mémoire. Ces outils sont ensuite utilisés dans un chapitre sur la performance et la fiabilité intrinsèque de l'eSTM. Le mode de programmation résultant de la topologie de la cellule est décrit afin de comprendre les dépendances du mécanisme de programmation et les moyens de l'optimiser. L'amélioration de la fiabilité de l'oxyde tunnel est aussi étudié en tant que clé de la performance en cyclage et en rétention de l'eSTM. Enfin les limites et avantages de la miniaturisation de l'eSTM sont discutés. Dans le chapitre suivant, la variabilité extrinsèque de l'eSTM est étudiée sur la macrocell. Chacune des sources de variabilité est évaluée pour extraire leurs origines liées soit au procédé de fabrication ou au design du microcontrôleur. Ce chapitre se clot sur la relation entre la fiabilité et la variabilité de la cellule mémoire. L'importance de l'étude statistique par des moyens adéquates comme la macrocell est mise en valeur par le lien direct de cause à effet entre la variabilité et la fiabilité ce qui peut affecter la fiabilité du produit, et donc sa durée de vie ou son rendement
Split-gate memory technologies propose non negligible improvement of the performance and reliability of embedded non-volatile memory in microcontroller products targeting growing market such as automotive or Internet of Things. In this thesis, a unique and innovative split-gate memory based on a trench select transistor, called embedded Select Trench Memory (eSTM) is presented. After a concise state of art, a chapter is devoted to the presentation of several tools to improve the characterization and analysis of the memory from single cell to testchip. Especially tools to analyze the testchip's bitmap are proposed for the memory reliability and variability evaluation and optimization. These methodologies are then deployed in a chapter focusing on the eSTM intrinsic performance and reliability. The unique programming scheme due to the cell topology is described to understand the dependency of the programming mechanisms and the way to improve it. Then the tunnel oxide reliability improvement is studied as a key to eSTM cycling and retention. Finally, the limitations and advantages of the eSTM shrinking are discussed. In the following chapter, the extrinsic variability of the eSTM is studied based on the testchip. Each sources of variability are outsourced, and studied to extract their root causes which are either process-related, or design/layout related. This chapter closes on the relation between the reliability weaknesses and the memory variability. It highlights the importance of statistics study through adapted device such as testchip and the causal connection between the variability and the reliability that can affect the product reliability, lifetime and yield

Controlled auto-ignition (CAI), also known as HCCI combustion in a gasoline engine has been extensively researched due to their potential of improved engine efficiency and low NOx emission. However, the combustion timing and the phasing of conventional CAI combustion depend on the in-cylinder condition, such as temperature and combustible mixture strength and thus cannot be directly controlled. In this study, direct DME (Dimethyl Ether) injection was adopted to increase the ignitability of premixed gasoline/air charge and to trigger the auto ignition of premixed charge. Re-breathing valve strategies were used to obtain hot internal EGR to eliminate a need of intake heating. Firstly, the pilot valve opening event, including its opening and closing timing, valve lift and dwell duration between the main valve event, was analysed by the WAVE simulation. Based on the analysis a re-breathing cam lobe was manufactured and installed on a Ricardo E6 engine to achieve the intake rebreathing and exhaust rebreathing operations. The intake re-breathing was realised by the pilot intake valve opening during the exhaust stroke and the exhaust re-breathing was achieved by the secondary exhaust valve opening during the intake stroke. Effects of the pilot intake valve open timing, 2nd DME injection timing, split DME injection ratio, air/fuel ratio and compression ratio were examined during the intake rebreathing operation. Then the performance and emission characteristics of DME assisted gasoline CAI combustion were examined during the exhaust re-breathing operation. Finally, results of the intake and exhaust re-rebreathing operations were compared to the conventional SI operation. The experimental study found that both the intake and the exhaust re-breathing operations provided enough heat to initiate DME assisted gasoline CAI combustion. The direct DME injection enabled to control the start of combustion and phasing. The quantity of the first DME injection showed greater effect than its timing, whereas the injection timing of 2nd DME injection had more dominant effect than its quantity. The exhaust re-breathing strategy provided stratified and hotter internal EGR that does not impact negatively on the volumetric efficiency because exhaust gas was re-breathed from the exhaust port during the intake stroke. High load of both CAI and SI baseline operations were limited by knocking combustion and their low load were limited by incomplete combustion. Exhaust re-breathing operation extended substantially the operational range of the DME assisted gasoline CAI combustion. Extremely low NOx emissions were obtained by DME/gasoline CAI operations. Most importantly, the exhaust rebreathing method produced dramatically improved overall efficiency of 43% compared to 28% of SI operation at a typical part-load operation of 4.0-5.0bar IMEP. It was also found that slightly improved efficiency and the extended operation range could be obtained by 33%:67% split DME injection ratio at higher load, while 67%:33% split DME injection ratio at lower load.

Följande examensarbete handlar om att ta fram konstruktionsförslag för en kopplingsmekanism som möjliggör delning av SverigeGrepens stallgrep. Produkten SverigeGrepen är med sin särskilda utformning och låga vikt ett ergonomiskt mockningsredskap. På grund av dess längd och form tillkommer en avgift för skrymmande paket vilket resulterar i en hög fraktkostnad. En lösning på detta problem är att skaftet delas itu, vilket tillåter produkten att fraktas i ett mindre paket. Vid ankomst hos kund monteras produkten med hjälp av kopplingsmekanismen. Lösningen ska innebära en minimal påverkan på egenskaper jämfört med hur produkten ser ut idag, som vikt och hållfasthet. För att erhålla ett teoretiskt underlag för problemet genomfördes en litteraturstudie. Denna behandlade områden som formsprutning och konstruktionsregler, finita elementmetoden, material, konceptval samt tidigare studier. Studien fortsatte med benchmarking och framställandet av en produktkravspecifikation. Dessa användes som grund för att generera olika koncept, där de mest lovande konstruerades i CAD. Metoder för konceptval applicerades, där slutligen två av koncepten valdes att kombineras inför en vidareutveckling. Resultatet av arbetet är ett konstruktionsförslag för en pluggliknande kopplingsmekanism som monteras på skaftets insida. Denna lösning har en låg vikt, klarar vardaglig belastning och tillåter montering av SverigeGrepens delade skaft.
This thesis aim is to develop a design proposal for a coupling mechanism for SverigeGrepen’s mucking tool which enables a splitting of its shaft and thus subsequently offer the ability to reliably mount them back together. SverigeGrepen is a lightweight product with a special design that makes it an ergonomic mucking tool. Due to the products length and shape a package fee is added in conjunction with its shipping which results in a high delivery cost. A proposal to solve this problem is a splitting of its shaft, which allows the product to be shipped in a smaller package. The product is assembled upon arrival at the customer. The solution should also have a minimal negative impact on SverigeGrepen’s existing product, such as its weight and strength. A literature study was conducted to obtain a theoretical basis. The study treated areas such as injection molding and rules for plastic design, as well as the finite element method, materials, concept selection and previous research. The study continued with market research and the development of a product requirement specification. These were used as a basis for generating product concepts, of which the most promising drafts were designed in CAD. Methods for concept selection were applied, where finally two of the concepts were chosen to be combined for further development. The result is a design proposal for a plug-like coupling mechanism that is mounted on the inside of the products shaft parts. The proposed solution offers a low total weight, endure the stress associated with everyday usage and allows the assembly of SverigeGrepen’s splitted shaft parts.

Thesis (M.S.)--University of Wisconsin--Madison, 1993.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 109-111).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1992.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 110-114).

碩士
國立臺灣科技大學
電子工程系
107
This thesis proposes a non-contact vital-sign sensor based on the principle of injection-locking, which is applied to detect respiration and wrist/finger pulse. Since the proposed sensor is developed based on both the injection-locked principle and perturbation theory, it is named as “perturbation-injection-locked (PIL) sensor” in this thesis. The PIL sensor uses a complementary split ring resonator (CSRR) as the frequency selective element and sensing component. As it is operated in the near-field region, it has the advantages of low radiation power and high sensitivity of distinguishing dielectric constant. Since this sensor outputs a frequency-modulation and amplitude-modulation signal, in this thesis, the amplitude-demodulation and frequency-demodulation techniques are employed to acquire the baseband vital-sign signals, respectively. The amplitude demodulator is implemented by the microwave differentiator and the envelope detector; the frequency demodulator uses the phase-locked loop (PLL). After demodulation, the signal is sent into the microcontroller (MCU) for analog-to-digital conversion (ADC). Finally, the digital signal is transmitted to the mobile devices via the Bluetooth interface for real-time monitoring. In this thesis, the proposed sensors have the advantages of low cost, low circuit complexity, and high sensitivity. As compared with the measured results of Thought Technology Biofeedback System, the measurement accuracy of the proposed PIL sensors has been successfully demonstrated.

碩士
國立臺灣科技大學
電子工程系
102
The important blocks in the phase locked loop (PLL) are the voltage controlled oscillator (VCO) and the divider circuit. The most power consumption of PLL consumes in VCO and divider. The VCO is requested a low phase-noise to avoid corrupting the mixer-converted signal by close interfering tones for VCO circuit, and the Figure of Merit (FOM) of VCO can be determined by it’s performance. Firstly, this thesis designs complementary Colpitts voltage controlled oscillator, A 0.7GHz Colpitts oscillator is designed and implemented in a 0.18μm CMOS 1P6M process. It consists of a Colpitts negative resistance cell and an open square loop resonator. At the supply voltage of 1.8 V, the output phase noise of the oscillator is -86.28 dBc/Hz at 1MHz offset frequency from the carrier frequency of 0.7 GHz(Using in UHF Band). The FOM(figure of merit) is -135.57dBc/Hz. Total oscillator core power consumption is 5.76 mW. Secondly, a new wide locking range divide-by-3 injection-locked frequency divider (ILFD) using a standard 0.18 μm BiCMOS process is presented. The ILFD uses a cross-coupled nMOSFET oscillator with an HBT tail and it also use two HBT injection SiGe HBTs. The injection HBTs serve as harmonic and nonlinear mixers. The core power consumption of the ILFD core is 8.328 mW. The divider’s free-running frequency is tunable from 4.32 to 3.78 GHz by tuning the varactor’s control bias, and at the incident power of 0 dBm. The maximum locking range is 1.87 GHz (23.71%), The incident frequency from 6.95 to 8.82 GHz. The operation range is 2.85 GHz (36.42%), from 6.4 to 9.25 GHz. In addition, the ILFD uses a cross-coupled nMOSFET oscillator with an HBT tail and it also use two HBT injection SiGe HBTs. The effect of hot-carrier stressed injection HBTs on the performance of the ILFD is studied. The stress induces the shift in oscillation frequency, phase noise and HBT output characteristics. It is found the locking range decreases with stress time at fixed dc injection base-emitter bias. Thirdly , a new wide locking range divide-by-3 injection-locked frequency divider (ILFD) using a standard 0.18 μm CMOS process is presented. The ILFD is based on a class-C capacitive cross-coupled oscillator. By changing the dc gate bias of cross-coupled transistors to below the dc drain voltage, the locking range of ILFD has been improved. At the supply voltage of 1.8 V, the core power consumption of the ILFD core is 10.7 mW. The incident power of 0 dBm the divider’s maximum locking range is 3.3 GHz (24.17%),with the incident frequency from 12 to 15.3 GHz. At incident power of 0 dBm the divider’s operation range is 4.8 GHz (35.2%), from the incident frequency 10.5 to 15.3 GHz. Finally ,a wide locking range divide-by-3 injection-locked frequency dividers (ILFDs) using a standard 0.18 μm CMOS process are presented. The ILFDs are based on a cross-coupled n-core MOS LC-tank oscillator with either injection NMOSFETs or pMOSFETs. The core power consumption of the ILFD core with injection nMOSFETs is 10.8 mW at the supply voltage of 0.9V and with circuit core current of 12mA. At the incident power of 0 dBm the maximum locking range is 4.2 GHz (37.17%), from the incident frequency 9.2 to 13.4 GHz. The core power consumption of the ILFD core with injection pMOSFETs is 13.77 mW at the supply voltage of 0.9V and with circuit core current of 15.3mA. At the incident power of 0 dBm the maximum locking range is 2.4 GHz (25%), from the incident frequency 8.4 to 10.8 GHz.