Flame Propagation and Knock Detection Using an Optical Fiber Technique in a Spark-ignition Engine
Title | Flame Propagation and Knock Detection Using an Optical Fiber Technique in a Spark-ignition Engine PDF eBook |
Author | Kwang Min Chun |
Publisher | |
Pages | 7 |
Release | 1993 |
Genre | Flame |
ISBN |
Spark Ignition Engine Knock Detection Using In-cylinder Optical Probes
Title | Spark Ignition Engine Knock Detection Using In-cylinder Optical Probes PDF eBook |
Author | Zhihong Sun |
Publisher | |
Pages | 362 |
Release | 1997 |
Genre | Spark ignition engines |
ISBN |
Detection of Flame Propagation During Knocking Combustion by Optical Fiber Diagnostics
Title | Detection of Flame Propagation During Knocking Combustion by Optical Fiber Diagnostics PDF eBook |
Author | U. Spicher |
Publisher | |
Pages | 10 |
Release | 1986 |
Genre | Combustion |
ISBN |
Modeling of End-Gas Autoignition for Knock Prediction in Gasoline Engines
Title | Modeling of End-Gas Autoignition for Knock Prediction in Gasoline Engines PDF eBook |
Author | Andreas Manz |
Publisher | Logos Verlag Berlin GmbH |
Pages | 263 |
Release | 2016-08-18 |
Genre | Science |
ISBN | 3832542817 |
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.
Relation Between Spark-ignition Engine Knock, Detonation Waves, and Autoignition as Shown by High-speed Photography
Title | Relation Between Spark-ignition Engine Knock, Detonation Waves, and Autoignition as Shown by High-speed Photography PDF eBook |
Author | Cearcy D. Miller |
Publisher | |
Pages | 72 |
Release | 1946 |
Genre | Combustion |
ISBN |
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.
Application of a New Optical Fiber Technique for Flame Propagation Diagnostics in Internal Combustion Engines
Title | Application of a New Optical Fiber Technique for Flame Propagation Diagnostics in Internal Combustion Engines PDF eBook |
Author | Ulrich Spicher |
Publisher | |
Pages | 10 |
Release | 1988 |
Genre | Flame |
ISBN |
Knocking Combustion of Methane-Based and Highly Knock Resistant Liquid Fuels
Title | Knocking Combustion of Methane-Based and Highly Knock Resistant Liquid Fuels PDF eBook |
Author | Marcel Eberbach |
Publisher | Springer Nature |
Pages | 143 |
Release | 2021-07-22 |
Genre | Technology & Engineering |
ISBN | 3658351780 |
Marcel Eberbach provides insight into the investigations of the knocking behavior of methane-based fuels and compares them with the knocking behavior of very high knock resistant liquid fuels during engine combustion. With pressure-based knock detection algorithms and thermodynamic evaluation, the atypical knocking combustion phenomena are evaluated with respect to the abnormalities on the heat release curve. Based on the investigated fuels an engine specific relation between the fuel index numbers (RON and MN) and the actual knock resistance of the fuels by means of the motor methane number was established and applied to the investigated gaseous and liquid fuels during knocking combustion.