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Showing 1 to 20 of 23 for “"combustion control"”.
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Optimised combustion control for different diesel fuels
Includes bibliographical references (leaves 51-53).
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Active combustion control : modeling, design and implementation
Continuous combustion systems common in propulsion and power generation applications are susceptible to thermoacoustic instability, which occurs under lean burn conditions close to the flammability where most emissions and efficiency benefits are achieved, and near stoichiometry where often high …
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Characteristics of Active Combustion Control for Liquid-Fuel Systems with Proportional Primary Fuel Modulation
The first part of this work focuses on control experiments performed on an unstable kerosene-fueled turbulent combustor. Using a phase shift controller and primary fuel modulation stability is successfully gained for a wide band of global equivalence ratios allowing the limitations of the control …
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Design and Validation of a Proportional Throttle Valve System for Liquid-Fuel Active Combustion Control
… one of the most promising methods for active combustion control. To attenuate the large pressure oscillations in the combustion chamber, the fuel is pulsed so that the heat release rate fluctuations damp the pressure oscillations in the combustor. This thesis focuses on the development and …
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Closed-Loop Combustion Control of a Multi Cylinder HCCI Engine using Variable Compression Ratio and Fast Thermal Management
… efficiency of the SI engine. A third internal combustion engine type, which combines the principles of the SI and CI engines, has the potential to meet demands from society in terms of current and foreseeable future emissions regulations. This engine type is called Homogeneous Charge …
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The Design and Construction of a High Bandwidth Proportional Fuel Injection System for Liquid Fuel Active Combustion Control
… experienced a sudden increase of interest in the control of thermo-acoustic instabilities, in particular through the use of fuel modulation techniques. The primary goal of this research was to design, construct and characterize a high bandwidth proportional fuel injection system, which could be …
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Robust design evolution and impact of In-Cylinder Pressure Sensors to combustion control and optimization : a systems and strategy perspective
… cost requirements for application to closed loop control and monitoring of production automotive engines. Using the Robust Design framework as a compass, this thesis first checks the evidence for emergence followed by tracking the evolution of the sensor component itself and its application to …
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Active Stabilization of Thermoacoustic Oscillation
Combustion processes serve as important sources of energy for both power generation and for transport, ranging from large scale power stations to micro turbines and aeroplane engines. Lean premixed combustion offers a potential to reduce the emission levels, but suffers from instability problems …
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Effect of market fuel variation and cetane improvers on CAI combustion in a GDI engine
… the fuel conversion efficiency of internal combustion engines and simultaneously reducing their emissions. One promising technology is that of Controlled Auto Ignition (CAI) combustion. The lack of direct combustion control makes control of CAI combustion challenging. Practical …
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Design and Validation of a High-Bandwidth Fuel Injection System for Control of Combustion Instabilities
… of fuel injection hardware used for active combustion control is not well established in the gas turbine industry. The primary reason for this is that the underlying mechanisms governing the flow rate authority downstream of the nozzle are not well understood. A detailed investigation of two …
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Two contrasting approaches to auto-ignition modelling for HCCI engines
… models formulated for the emulation of combustion dynamics in Homogeneous Charge Compression Ignition (HCCI) engines. The first (empirical) auto-ignition model was adapted from its previously published form, for HCCI engine model implementation. This model was then combined with an …
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Spark Breakdown Voltage Sampling During Early Stage Compression
… a novel methodology to enable cycle by cycle control of a two-stroke cycle type engine. These engines are well known for offering high specific power density solutions, however, this advantage cannot be fully exploited without new technologies enabling significantly reduced emissions and …
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Implementation of Adaptive Filter Algorithms for the Suppression of Thermoacoustic Instabilities
… algorithms and test their performance in active combustion control. Several algorithms were incorporated, which are divided into gradient descent algorithms and pattern searches. The algorithms were tested on three separate platforms. The first was an analog electronic simulator, which uses a …
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An Exploration of Secondary Fuel Injection as Actuation for Control of Combustion Instabilities in a Laminar Premixed Tube Combustor
Active control of combustion instabilities through secondary fuel injection is a control method that has gained a lot of attention in the past decade. Previous control schemes with acoustic loudspeakers are not practical in full-scale gas turbines due to the extreme temperatures and acoustic power …
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Effects of Thermoacoustic Oscillations on Spray Combustion Dynamics with Implications for Lean Direct Injection Systems
… on the active suppression and even complete control of these instabilities. Intuitively, development of effective active combustion control methodologies is strongly dependent on the knowledge of the onset and sustenance of thermoacoustic instabilities. Specially, non-premixed spray …
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Phase Shift Control: Application and Performance Limitations With Respect to Thermoacoustic Instabilities
… the turbine's longevity and reliability. Active control of the pressure oscillations, called thermoacoustic instabilities, has been sought as passive abatement of these instabilities does not provide adequate damping and is often impractical on a large scale. Phase shift control of the …
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Subharmonic and Non-Subharmonic Pulsed Control of Thermoacoustic Instabilities: Analysis and Experiment
… cycles. Much work has been done using linear controllers to eliminate these instabilities. Many experimenters in the field have used pulsed and subharmonic fuel controllers to eliminate these instabilities, but very little investigative work has been done on these controllers. The goal of this …
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Characterization and Control of Multi-Cylinder Partially Premixed Combustion
In the last decade diesel combustion has developed in a new direction. Research has been carried out trying to prolong the ignition delay and enhance fuel/air premixing to avoid diffusion combustion as well as lowering the combustion temperature through use of EGR. One of these new combustion …
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Adaptive Control Methods for Non-Linear Self-Excited Systems
… Because there is no external disturbance, control of these self-excited systems requires that the open loop system dynamics are altered so that any unstable open loop poles are stabilized in the closed loop. This work examines a variety of adaptive control approaches for controlling a …
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