Download or read book Active Flow Control for Maximizing Performance of Spark Ignited Stratified Charge Engines Final Report written by and published by . This book was released on 2002 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reducing the cycle-to-cycle variability present in stratified-charge engines is an important step in the process of increasing their efficiency. As a result of this cycle-to-cycle variability, fuel injection systems are calibrated to inject more fuel than necessary, in an attempt to ensure that the engines fire on every cycle. When the cycle-to-cycle variability is lowered, the variation of work per cycle is reduced and the lean operating limit decreases, resulting in increased fuel economy. In this study an active flow control device is used to excite the intake flow of an engine at various frequencies. The goal of this excitation is to control the way in which vortices shed off of the intake valve, thus lowering the cycle-to-cycle variability in the flow field. This method of controlling flow is investigated through the use of three engines. The results of this study show that the active flow control device did help to lower the cycle-to-cycle variability of the in-cylinder flow field; however, the reduction did not translate directly into improved engine performance.
Download or read book Active Flow and Combustion Control 2018 written by Rudibert King and published by Springer. This book was released on 2018-09-03 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book reports on the latest theoretical and experimental findings in the field of active flow and combustion control. It covers new developments in actuator technology and sensing, in robust and optimal open- and closed-loop control, as well as in model reduction for control, constant volume combustion and dynamic impingement cooling. The chapters reports oncutting-edge contributions presented during the fourth edition of the Active Flow and Combustion Control conference, held in September 19 to 21, 2018 at the Technische Universität Berlin, in Germany. This conference, as well as the research presented in the book, have been supported by the collaborative research center SFB 1029 on “Substantial efficiency increase in gas turbines through direct use of coupled unsteady combustion and flow dynamics”, funded by the DFG (German Research Foundation). It offers a timely guide for researchers and practitioners in the field of aeronautics, turbomachinery, control and combustion.
Download or read book Active Flow and Combustion Control 2021 written by Rudibert King and published by Springer Nature. This book was released on 2021-11-12 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book reports on the latest theoretical and experimental findings in the field of active flow and combustion control, in the context of energy conversion for power and propulsion systems. It covers new developments in actuator technology and sensing, robust and optimal open- and closed-loop control, model reduction for control purposes, and unsteady turbine cooling and performance, among other relevant topics. Gathering contributions to the Active Flow and Combustion Control (AFCC 2021), held virtually on September 28-29, 2021, from the Technische Universität Berlin, Germany, this book describes research that has been carried out within, and supported by, the collaborative research center SFB 1029 on “Substantial efficiency increase in gas turbines through direct use of coupled unsteady combustion and flow dynamics”, and funded by the German Research Foundation (DFG). It highlights theoretical and practical aspects, and corresponding solutions, that are important for the development of future energy conversion systems, thus offering a timely guide for researchers and practitioners in the field of aeronautics, turbomachinery, control and combustion.
Download or read book Improving the Performance and Fuel Consumption of Dual Chamber Stratified Charge Spark Ignition Engines written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A combined experimental and theoretical investigation of the nature of the combustion processes in a dual chamber stratified charge spark ignition engine is described. This work concentrated on understanding the mixing process in the main chamber gases. A specially constructed single cylinder engine was used to both conduct experiments to study mixing effects and to obtain experimental data for the validation of the computer model which was constructed in the theoretical portion of the study. The test procedures are described. Studies were conducted on the effect of fuel injection timing on performance and emissions using the combination of orifice size and prechamber to main chamber flow rate ratio which gave the best overall compromise between emissions and performance. In general, fuel injection gave slightly higher oxides of nitrogen, but considerably lower hydrocarbon and carbon monoxide emissions than the carbureted form of the engine. Experiments with engine intake port redesign to promote swirl mixing indicated a substantial increase in the power output from the engine and, that an equivalent power levels, the nitric oxide emissions are approximately 30% lower with swirl in the main chamber than without swirl. The development of a computer simulation of the combustion process showed that a one-dimensional combustion model can be used to accurately predict trends in engine operation conditions and nitric oxide emissions even though the actual flame in the engine is not completely one-dimensional, and that a simple model for mixing of the main chamber and prechamber intake gases at the start of compression proved adequate to explain the effects of swirl, ignition timing, overall fuel air ratio, volumetric efficiency, and variations in prechamber air fuel ratio and fuel rate percentage on engine power and nitric oxide emissions. (LCL).
Download or read book Improving Efficiency of Spark ignited Stoichiometrically Operated Natural Gas Engines written by Dan Giordano ((Program manager, Sturman Industries)) and published by . This book was released on 2013 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Eddy Simulations of Motored Flow and Combustion in a Stratified Charge Direct Injection Spark Ignition Engine written by Samuel Kazmouz and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Stratified-charge, spray-guided, spark-ignition, direct-injection operation offers efficiency improvements to conventional engines used in light-duty vehicles. However, cycle-to-cycle variability (CCV) impedes extracting the full efficiency potential of such advanced engine operation modes. In this dissertation, multi-cycle motored and fired large-eddy simulation (LES) results of an optically-accessible single-cylinder four-valve direct-injection spark- ignition engine, called G4VDI, are presented and compared to experimental results. The main objective is to investigate the root causes of CCV in stratified-charge engines. For motored operation, four sets of 60 consecutive LES cycles, with different operating conditions, are compared with experiments. LES is able to capture the wave dynamics of the ports and the in-cylinder pressure with a difference of 0.12%-2.5%, compared to experimental results. The LES velocity fields are compared with particle-image velocimetry measurements at six cutting planes. Based on the local and volume-averaged structure and magnitude indexes, it is found that LES is able to reproduce key flow events and capture large-scale in-cylinder flow structures, especially in high tumble/swirl conditions. Using proper orthogonal decomposition, LES shows that high tumble/swirl conditions produce low CCV flow fields. CCV of in-cylinder pressure ranged between 0.13% and 0.23%. For fired operation, and using the thickened flame model (TFM), 20 consecutive LES cycles of a homogeneous-charge engine operation mode are presented followed by spray-characterization in four different ambient conditions. These results lay the foundation for two stratified-charge engine operation modes, in which 20 and 35 consecutive LES cycles are compared with experiments, respectively. TFM-LES is extended for partially premixed flames and is able to reproduce experimental in-cylinder pressure (0.5%-10%), cyclic variability (20.5%-22.7%) in global and local quantities, local fuel vapor distributions, and heat release curves for homogeneous and stratified burn. Tuning TFM to reduce the burn rate increases the tendency to produce misfires, as well as the levels of CCV. Correlation analysis done on the stratified-charge LES results suggests that the influence of the early burn on the subsequent flame development is more subtle for stratified combustion compared to homogeneous combustion, that is the local conditions at the spark plug when the flame starts propagating are more influential than the conditions at spark timing, and that the injection event creates velocity conditions which might be favorable or unfavorable for the combustion event. The main contributions of this dissertation are extending TFM to highly stratified spray combustion, showing that LES can reproduce experimentally measured flow and combustion behavior in a realistic engine, including CCV, and analyzing LES to provide new insight into CCV and misfires of stratified-charge engines.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1980 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Assessment of Fuel Economy Technologies for Light Duty Vehicles written by National Research Council and published by National Academies Press. This book was released on 2011-06-03 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various combinations of commercially available technologies could greatly reduce fuel consumption in passenger cars, sport-utility vehicles, minivans, and other light-duty vehicles without compromising vehicle performance or safety. Assessment of Technologies for Improving Light Duty Vehicle Fuel Economy estimates the potential fuel savings and costs to consumers of available technology combinations for three types of engines: spark-ignition gasoline, compression-ignition diesel, and hybrid. According to its estimates, adopting the full combination of improved technologies in medium and large cars and pickup trucks with spark-ignition engines could reduce fuel consumption by 29 percent at an additional cost of $2,200 to the consumer. Replacing spark-ignition engines with diesel engines and components would yield fuel savings of about 37 percent at an added cost of approximately $5,900 per vehicle, and replacing spark-ignition engines with hybrid engines and components would reduce fuel consumption by 43 percent at an increase of $6,000 per vehicle. The book focuses on fuel consumption-the amount of fuel consumed in a given driving distance-because energy savings are directly related to the amount of fuel used. In contrast, fuel economy measures how far a vehicle will travel with a gallon of fuel. Because fuel consumption data indicate money saved on fuel purchases and reductions in carbon dioxide emissions, the book finds that vehicle stickers should provide consumers with fuel consumption data in addition to fuel economy information.
Download or read book Automotive Spark Ignited Direct Injection Gasoline Engines written by F. Zhao and published by Elsevier. This book was released on 2000-02-08 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: The process of fuel injection, spray atomization and vaporization, charge cooling, mixture preparation and the control of in-cylinder air motion are all being actively researched and this work is reviewed in detail and analyzed. The new technologies such as high-pressure, common-rail, gasoline injection systems and swirl-atomizing gasoline fuel injections are discussed in detail, as these technologies, along with computer control capabilities, have enabled the current new examination of an old objective; the direct-injection, stratified-charge (DISC), gasoline engine. The prior work on DISC engines that is relevant to current GDI engine development is also reviewed and discussed. The fuel economy and emission data for actual engine configurations have been obtained and assembled for all of the available GDI literature, and are reviewed and discussed in detail. The types of GDI engines are arranged in four classifications of decreasing complexity, and the advantages and disadvantages of each class are noted and explained. Emphasis is placed upon consensus trends and conclusions that are evident when taken as a whole; thus the GDI researcher is informed regarding the degree to which engine volumetric efficiency and compression ratio can be increased under optimized conditions, and as to the extent to which unburned hydrocarbon (UBHC), NOx and particulate emissions can be minimized for specific combustion strategies. The critical area of GDI fuel injector deposits and the associated effect on spray geometry and engine performance degradation are reviewed, and important system guidelines for minimizing deposition rates and deposit effects are presented. The capabilities and limitations of emission control techniques and after treatment hardware are reviewed in depth, and a compilation and discussion of areas of consensus on attaining European, Japanese and North American emission standards presented. All known research, prototype and production GDI engines worldwide are reviewed as to performance, emissions and fuel economy advantages, and for areas requiring further development. The engine schematics, control diagrams and specifications are compiled, and the emission control strategies are illustrated and discussed. The influence of lean-NOx catalysts on the development of late-injection, stratified-charge GDI engines is reviewed, and the relative merits of lean-burn, homogeneous, direct-injection engines as an option requiring less control complexity are analyzed.
Download or read book Improving the Performance and Exhaust Emissions of Dual Chamber Stratified Charge Spark Ignition Engines written by Kenneth William Grandys and published by . This book was released on 1977 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Numerical Methods for Modeling Flow Field During Intake Stroke of Spark ignited Engines written by Carlos Lozano Hontecillas and published by . This book was released on 2014 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent changes in the exhaust emission legislations obliged the automotive industry to reduce the emissions and improve the fuel saving. Stratified charge direct-injection engines were indicated as a convenient short-term solution to adapt spark-ignited engines to these requirements. In this context, the objective of this thesis was to evaluate the effectiveness of the intake system for a stratified charge spark-ignited direct-injection engines by means of a computational fluid dynamic tool. The effectiveness of the intake system in such engines is assessed by the tumble number. Therefore, the first objective of the project was to compare differences between transient and steady-state simulations in calculating the tumble number. Steady-state simulations are mostly used by companies since they require less computational power than transient simulations. However, the differences of the model between both types of simulations speak in favor of a clear advantage for transient simulation to calculate an approximation of the tumble number. The second objective of the project was to perform an enhancement of the mesh corresponding to steady-state model. This was performed by refining the mesh through different programs and studying the impact of each refinement criteria on the quality of the results.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1980 with total page 1280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Injection Stratified Charge Engine Development written by F. W. Eyre and published by . This book was released on 1982 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of particulate emission control techniques for spark ignition engines written by and published by . This book was released on 1971 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Control Strategies for Homogeneous Charge Compression Ignition Engines written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Performance Model for the Texaco Controlled Combustion Stratified Charge Engine written by Bhag Chand Jain and published by . This book was released on 1976 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model has been developed to predict the performance of the Texaco Controlled Combustion, Stratified Charge Engine starting from engine geometry, fuel characteristics and the operation conditions. This performance model divides the engine cycle into the following phases: Intake, Compression, Rapid Combustion, Mixing - Dominated Expansion, Heat - Transfer Dominated Expansion and Exhaust. During the rapid combustion phase, the rate of heat release is assumed to be controlled by the rate of fuel injection and the gas-to-fuel ratio. Entrainment of the surrounding gas by the plume is assumed to be controlled by the turbulent eddy entrainment velocity. A plume geometry model has been developed to obtain the surface area of the plume for entrainment during the mixing dominated phase. The model also gives the wall areas in contact with the hot, burned gas plume and the relatively cold unburned gas for heat transfer calculations. Comparison of the model predictions with the available experimental data shows good agreement. In addition, the potential of the performance model as a design tool is demonstrated with a parametric analysis. (Author).
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1981-03 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
