Download or read book Knock Modelling in Spark ignition Engines and a Study of the Effect of Combustion Instability on Knock written by G. Ganti and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Phenomenological Knock Model for the Development of Future Engine Concepts written by Alexander Fandakov and published by Springer. This book was released on 2018-12-28 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of 0D/1D knock models available today are known for their poor accuracy and the great effort needed for their calibration. Alexander Fandakov presents a novel, extensively validated phenomenological knock model for the development of future engine concepts within a 0D/1D simulation environment that has one engine-specific calibration parameter. Benchmarks against the models commonly used in the automotive industry reveal the huge gain in knock boundary prediction accuracy achieved with the approach proposed in this work. Thus, the new knock model contributes substantially to the efficient design of spark ignition engines employing technologies such as full-load exhaust gas recirculation, water injection, variable compression ratio or lean combustion. About the Author Alexander Fandakov holds a PhD in automotive powertrain engineering from the Institute of Internal Combustion Engines and Automotive Engineering (IVK) at the University of Stuttgart, Germany. Currently, he is working as an advanced powertrain development engineer in the automotive industry.

Download or read book Analysis of Spark ignition Engine Knock as Seen in Photographs Taken at 200 000 Frames a Second written by Cearcy D. Miller and published by . This book was released on 1946 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A motion-picture of the development of knock in a spark-ignition engine is presented, which consists of 20 photographs taken at intervals of 5 microseconds, or at a rate of 200,000 photographs a second, with an equivalent wide-open exposure time of 6.4 microseconds for each photograph. A motion picture of a complete combustion process, including the development of knock, taken at the rate of 40,000 photographs a second is also presented to assist the reader in orienting the photographs of the knock development taken at 200,000 frames per second are analyzed and the conclusion is made that the type of knock in the spark-ignition engine involving violent gas vibration originates as a self-propagating disturbance starting at a point in the burning or autoigniting gases and spreading out from that point through the incompletely burned gases at a rate as high as 6800 feet per second, or about twice the speed of sound in the burned gases. Apparent formation of free carbon particles in both the burning and the burned gas is observed within 10 microseconds after passage of the knock disturbance through the gases.

Download or read book Multidimensional Modeling of Combustion and Knock in Spark ignition Engines with Detailed Chemical Kinetics written by Long Liang and published by . This book was released on 2006 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reaction based Knock Predictive Modeling and Model based Stochastic Knock Limit Control of Spark ignition Engines written by Ruixue Li and published by . This book was released on 2020 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation studies the spark-ignition (SI) engine knock phenomenon, abnormal combustion due to the auto-ignition of end-gas ahead of the propagated flame front, resulting in the rapid chemical energy release with aggressive combustion, limiting the further improvement of thermal efficiency and even damaging the engine mechanically. A control-oriented combustion and pressure wave model with satisfactory accuracy and low computational effort is a necessity for the knock control strategy design. This dissertation develops a control-oriented knock predictive model that includes a two-zone reaction-based combustion model and a pressure wave model. This knock predictive model is capable of accurately describing the combustion process of a spark-ignited engine and predict the in-cylinder pressure oscillations under knocking combustion in real-time. Based on this model, a feedforward and feedback stochastic knock limit control strategy is developed to reduce the knock cyclic variability and control the knock mean-intensity below a desired up bound while keeping spark timing as close to engine maximum brake torque (MBT) timing as possible. A control-oriented two-zone reaction-based model to accurately describe the combustion process of a SI engine is first developed. Instead of using the conventional pre-determined Wiebe-based combustion model, a two-step chemical reaction model is utilized to predict the combustion process along with important thermodynamic parameters such as the mass-fraction-burned, in-cylinder pressure, temperatures and individual species mass changes in both zones. Sensitivities of model parameters are analyzed during the model calibration process. As a result, one set of calibration parameters are used to predict combustion characteristics over all engine operating conditions studied in this paper, which is the major advantage of the proposed method. Also, the proposed modeling approach is capable of modeling the combustion process for real-time simulations. As the by-product of the model, engine knock can also be predicted based on the Arrhenius integral in the unburned zone, which is valuable for model-based knock control. The proposed combustion model is intensively validated using the experimental data with a peak relative prediction error of 6.2% for the in-cylinder pressure. Based on this validated combustion model, a control-oriented pressure wave model for SI engines is further developed. This model is capable of predicting the in-cylinder pressure oscillations under knocking combustion in real-time and can be used for the model-based knock prediction and control. A pressure wave equation including the knock deadening behavior is proposed, simplified, and used to calculate the pressure perturbations generated by the knocking combustion. The boundary and initial conditions at knock onset are analyzed and the analytic solution of the pressure wave equation is obtained. The model is calibrated and validated over two different engine operating conditions at knock limit. The chemical kinetic-based Arrhenius integral (ARI) and the KI20 are used as the evaluation methods for knock onset and intensity prediction, and the knock frequency is studied with a fast Fourier transform of the filtered in-cylinder pressure oscillations. Especially, the knock characteristics associated with gas mixture properties at intake valve closing is analyzed based on the experimental data and their effect to knock cycle-to-cycle variation is also studied for the proposed model. In addition, this dissertation studies the correlation between in-cylinder mixture temperature at intake valve closing and the engine knock, along with knock cyclic variability based on the knock predictive model. A strong correlation between the intake temperature and knock intensity has been obtained and validated based on the simulation investigation and experiment data obtained at knock limit. Therefore, a model-based feedforward and feedback stochastic knock limit control strategy is developed to reduce the knock cycle-to-cycle variability and maintain the knock mean-intensity within a desired up bound by controlling the spark timing as close to MBT timing as possible. The control performance is validated with the simulation results to show the capability of the model-based feedforward and feedback stochastic knock limit control in significantly reducing the knock cyclic variability and improving the knock intensity distribution for the best fuel economy.

Download or read book Modelling Spark Ignition Combustion written by P. A. Lakshminarayanan and published by Springer Nature. This book was released on with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of End Gas Autoignition for Knock Prediction in Gasoline Engines written by Andreas Manz and published by Logos Verlag Berlin GmbH. This book was released on 2016-08-18 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: Downsizing of modern gasoline engines with direct injection is a key concept for achieving future CO22 emission targets. However, high power densities and optimum efficiency are limited by an uncontrolled autoignition of the unburned air-fuel mixture, the so-called spark knock phenomena. By a combination of three-dimensional Computational Fluid Dynamics (3D-CFD) and experiments incorporating optical diagnostics, this work presents an integral approach for predicting combustion and autoignition in Spark Ignition (SI) engines. The turbulent premixed combustion and flame front propagation in 3D-CFD is modeled with the G-equation combustion model, i.e. a laminar flamelet approach, in combination with the level set method. Autoignition in the unburned gas zone is modeled with the Shell model based on reduced chemical reactions using optimized reaction rate coefficients for different octane numbers (ON) as well as engine relevant pressures, temperatures and EGR rates. The basic functionality and sensitivities of improved sub-models, e.g. laminar flame speed, are proven in simplified test cases followed by adequate engine test cases. It is shown that the G-equation combustion model performs well even on unstructured grids with polyhedral cells and coarse grid resolution. The validation of the knock model with respect to temporal and spatial knock onset is done with fiber optical spark plug measurements and statistical evaluation of individual knocking cycles with a frequency based pressure analysis. The results show a good correlation with the Shell autoignition relevant species in the simulation. The combined model approach with G-equation and Shell autoignition in an active formulation enables a realistic representation of thin flame fronts and hence the thermodynamic conditions prior to knocking by taking into account the ignition chemistry in unburned gas, temperature fluctuations and self-acceleration effects due to pre-reactions. By the modeling approach and simulation methodology presented in this work the overall predictive capability for the virtual development of future knockproof SI engines is improved.

Download or read book Modeling and Simulation of Knock and Nitric Oxide Emissions in Turbocharged Direct Injection Spark Ignition Engines written by Dirk Linse and published by . This book was released on 2013-11-13 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Knocking in Gasoline Engines written by Michael Günther and published by Springer. This book was released on 2017-11-21 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book includes the papers presented at the conference discussing approaches to prevent or reliably control knocking and other irregular combustion events. The majority of today’s highly efficient gasoline engines utilize downsizing. High mean pressures produce increased knocking, which frequently results in a reduction in the compression ratio at high specific powers. Beyond this, the phenomenon of pre-ignition has been linked to the rise in specific power in gasoline engines for many years. Charge-diluted concepts with high compression cause extreme knocking, potentially leading to catastrophic failure. The introduction of RDE legislation this year will further grow the requirements for combustion process development, as residual gas scavenging and enrichment to improve the knock limit will be legally restricted despite no relaxation of the need to reach the main center of heat release as early as possible. New solutions in thermodynamics and control engineering are urgently needed to further increase the efficiency of gasoline engines.

Download or read book Relation Between Spark ignition Engine Knock Detonation Waves and Autoignition as Shown by High speed Photography written by Cearcy D. Miller and published by . This book was released on 1946 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: A critical review of literature bearing on the autoignition and detonation-wave theories of spark-ignition engine knock and on the nature of gas vibrations associated with combustion and knock results in the conclusion that neither the autoignition theory nor the detonation-wave theory is an adequate explanation of spark-ignition engine knock. A knock theory is proposed, combining the autoignition and detonation-wave theories, introducing the idea that the detonation wave develops in autoignited or afterburning gases, and ascribing comparatively low-pitched heavy knocks to autoignition but high-pitched pinging knocks to detonation waves with the possibility of combinations of the two types of knock.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 850 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Combustion Time on Knock in a Spark ignition Engine written by Donald Roger Diggs and published by . This book was released on 1953 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings written by and published by . This book was released on 1970 with total page 1532 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemical Kinetic Modelling of Autoignition Under Conditions Relevant to Knock in Spark Ignition Engines written by Hakan Serhad Soyhan and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The phenomenon called the ''engine knock'' is an abnonnal combustion mode inspark ignition (SI) engines. it might lead to very high peak pressure in the cylinderand serious damages in engines. Knock limits the compression ratio of the ~ngine. The higher compression ratiomeans the higher fuel conversion efficiency of the engine. it also means highercylinder pressure and thereby higher gas temperature which can cause knock becauseof shorter ignition delay time. Increasing compression ratio is the simplest strategyfor increasing the efficiency of combustion, so a more detailed understanding of theprocesses goveming knock is important.it is generally accepted that knock is initiated by autoignition in the unbumed gasmixture as a result of compression due to the f1ame front propagation and the piston movement. Auto ignition can be defined as spontaneous ignition of some part of thecharge in the cylinder. The autoignition is may cause an extremely rapid chemicalenergy release. it causes a high local pressure and propagation of pressure waveswith high amplitude across the combustion chamber. The rapid rise in pressure andthe vibration of the resultant pressure wave across the combustion chamber cause erosion of the piston, piston rings and head gaskets. Known measures to avoid theoccurrence of engine knock cause either environmental problems, for example theusage of MTBE or reduce the engine thennal efficiency , for example lowcompression ratio, high swirl or early ignition timing. Because of this, the occurrenceof knock was subject of continuous public and industrial research.A detailed investigation of the combustion processes in intemal combustion engines is necessary for the improvement of engine technology .Chemical kinetic model ofthe combustion process implemented into the computational f1uid dynamic sapplications for the prediction of gas f1ow in the combustion chamber provides anefficient tool in tenns of time and cost for the investigation and improvement of the combustion process.The software tools for the modeling of combustion processes in combustion devicesrequire the reduction of the kinetic model to a limited number of species. Since the engine geometry is very complex, the performnnance of commercial software productsfor combustion device optimization decreases considerably if the number of species exceeds about 10. Consequently, a variety of methods in chemical kinetic modelingare needed to construct a reaction mechanism for a complex fuel such as PRF and toreduce it to a low number of capable species without a loss of information that mightbe important for the accuracy of the calculations. One method having the following steps is The generation of a ''detailed reaction mechanism'',The construction of the ''skeletal mechanism'',The final reduction of the reaction mechanism using Quasi Steady State Approximations (QSSA).This study concentrates on the construction of the problem oriented reduced mechanism. A method for automatic reduction of detailed kinetic to reduced mechanisms for complex fuels is proposed. The method is based on the simultaneoususe of sensitivity, reaction-f1ow and lifetime analyses. The sensitivity analysis detects species that the overall combustion process is sensitive on. Small in accuracies, in calculating these species, result in large errors in the characteristic behavior of the chernical scheme. Species, not relevant for the occurrence of autoignition in the end-gas, are defined as redundant. The automatic detection of there dundant species is done by means of an analysis of the reaction f1ows from and towards the most sensitive species, the fuel, the oxidizer and the final products. Theyare identified and eliminated for different pre-set levels of minimum reaction flow and sensitivity to generate a skeletal mechanism. The resulting skeletal mechanism is investigated with lifetime analysis to get the final reduced mechanism. A measure ofspecies lifetimes is taken from the diagonal elements of the Jacobian matrix of the chernical source terms. The species with the lifetime shorter than and mass-fractionIess than specified limits are assumed to be in steady state and selected for removalfrom the skeletal mechanism. The reduced mechanism is valid for the parameter range of initial and boundary values that the analysis has been performed for.The proposed reduction method is exemplified on a detailed reaction mechanism foriso-octane/n-heptane rnixtures. The gas-phase chernistry is analyzed in the end gas of an SI engine, using a two-zone model with conditions chosen relevant for engine knock. Comparing results obtained from the skeletal and the reduced mechanism swith results from the detailed mechanism shows the accuracy of the resulting mechanisms. it is shown that the error in the mechanisms increase with increasingpre-set Ievels of reduction. This is visualized by the help of the predicted crank angle degree at which auto ignition in the end gas of the engine occurs.The reduced mechanism is used for investigation of the modeling of the auto ignitionin the SI engines. The effects of engine operator parameters such as compression ratio, spark advance, fuel equivalence ratio and engine speed on autoignition onsettime have been studied.This work shows that it is possible to achieve a simplified reaction mechanism withgood agreement to the original mechanism by the reduction method. Fundamental knowledge about the detailed mechanism is not necessary to apply the method. Theprocedure used for reduction is fully automatic and provides a fast technique togenerate the problem oriented reduced mechanisms.

Download or read book Natural Gas Engines written by Kalyan Kumar Srinivasan and published by Springer. This book was released on 2018-11-03 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the various advanced reciprocating combustion engine technologies that utilize natural gas and alternative fuels for transportation and power generation applications. It is divided into three major sections consisting of both fundamental and applied technologies to identify (but not limited to) clean, high-efficiency opportunities with natural gas fueling that have been developed through experimental protocols, numerical and high-performance computational simulations, and zero-dimensional, multizone combustion simulations. Particular emphasis is placed on statutes to monitor fine particulate emissions from tailpipe of engines operating on natural gas and alternative fuels.

Download or read book Knocking Combustion Observed in a Spark ignition Engine with Simultaneous Direct and Schlieren High speed Motion Pictures and Pressure Records written by Gordon E. Osterstrom and published by . This book was released on 1948 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report support simultaneous direct and schlieren photographs at 40,000 frames a second and correlated pressure records taken of knocking combustion in a special spark-ignition engine to ascertain intensity of certain end-zone reactions previously seen by schlieren photography alone.

Download or read book Combustion and Knock in Spark Ignition Engines written by T. Priede and published by . This book was released on 1991 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: