Download or read book Characterization of Knock and Prediction of Its Onset in a Spark ignition Engine written by Kwang Min Chun and published by . This book was released on 1988 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Predicting Knock Onset in a Spark Ignition Engine written by Jim Scot Cowart and published by . This book was released on 1990 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Characterization and Measurement of Autoignition and Knock in a Spark Ignition Engine written by Jonathan M. Borg and published by . This book was released on 2006 with total page 306 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 Characterization of Knock in a Spark ignition Engine written by Kwang Min Chun and published by . This book was released on 1989 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of the Knock Characteristics of Various Spark ignition Engine Fuels written by A. Joel Warren and published by . This book was released on 1939 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Knocking Combustion and Heat Transfer in Spark Ignition Engine written by Michalis Syrimis and published by . This book was released on 1996 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was conducted to investigate combustion and in-cylinder heat transfer characteristics under light and heavy knocking conditions in a spark ignition engine. A special, single cylinder, Mitsubishi R52 engine was used, in its extended piston configuration. Fast response heat flux probes on the piston and the cylinder head provided instantaneous surface temperature measurements at different locations, both inside and outside the end-gas region. The knocking combustion process was characterized by several knock indices, based on the net heat release analysis of cylinder pressure, as well as, the amplitude of the knock induced pressure fluctuations. Knock initiation and development were investigated by sampling cylinder pressure data at two different locations in the chamber. The cyclic variability associated with knocking combustion was investigated by studying the variation, as well as the interdependence of the knock indices, under different knock severity conditions. Finally, the effects of knock on heat transfer were explored by studying changes in ensemble-average heat flux with increasing knock intensity, and also by the magnitude of the correlation coefficients between peak heat flux and the developed knock indices. Evidence of multiple autoignition sites was found during the knock initiation process. Knock induced pressure waves were of acoustic nature, becoming weak shock waves in cases of violent autoignitions. Cyclic variability in knock intensity was found to be driven by variations in burn rate. The correlation between burn rate and knock intensity was higher for lower overall combustion rates. Under light knock, the ensemble-average peak heat flux at locations near the end-gas zone increased with spark advance, departing from its trend prior to the onset of knock. Under heavy knock, the ensemble-average peak heat flux increased over the entire piston crown. High statistical correlation (up to 0.80) was found between peak heat flux and certain of the autoignition indices within and near the end-gas zone. Knock was found to increase heat transfer by the 'scouring' action of the induced pressure waves on the wall thermal boundary layer. Apart from knock intensity, the location of autoignition initiation, and the characteristics of the flame and wave front patterns following autoignition were found to affect the magnitude of heat transfer changes.

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 Phenomena that Determine Knock Onset in Spark Ignition Engines written by Vikram Mittal and published by . This book was released on 2007 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Knock and Knock Intensity in a Spark Ignition Engine written by M. Karimifar and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Measure and Analysis for Determination of Combustion Knock Intensity in a Spark Ignition Engine written by Satheesh Rajh Rajagopalan and published by . This book was released on 2006 with total page 424 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 Measurement of Knock Characteristics in Spark ignition Engines written by R. Schutz and published by . This book was released on 1940 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents a discussion of three potential sources of error in recording engine knocking which are: the natural oscillation of the membrane, the shock process between test contacts, and the danger of burned contacts. Following this discussion, the paper calls attention to various results which make the bouncing-pin indicator appear fundamentally unsuitable for recording knock phenomena.

Download or read book Spark Ignition Engine Knock Detection Using In cylinder Optical Probes written by Zhihong Sun and published by . This book was released on 1997 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Spark ignition Engine Knock as Seen in Photgraphs Taken at 200 000 Frames Per Second written by Cearcy D. Miller and published by . This book was released on 1946 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spark Ignition Engine Simulation Using Two Zone Combustion Model with Knock Prediction written by Jianan Ma and published by . This book was released on 2014 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: