Engine Knock Prediction and Evaluation Based on Detonation Theory Using a Quasi-Dimensional Stochastic Reactor Model

Netzer, Corinna; Seidel, Lars; Pasternak, Michał; Klauer, Christian; Perlman, Cathleen; Ravet, Frédéric; Mauß, Fabian

doi:10.4271/2017-01-0538

Cited by 20 publications

(20 citation statements)

References 39 publications

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“…Lots of recent studies [17][18][19][20] used this detonation peninsula to analyze experimental and numerical occurrences of knock and LSPI in highly charged SI engines. It is therefore essential to validate the location of this peninsula for realistic gasoline fuel.…”

Section: = 0 ⁄mentioning

confidence: 99%

“…This methodology is too CPU time consuming as the objective is to analyze a large number of operating conditions to precisely define the detonation peninsula. The tabulated model TKI-LES model [15][16][17][18][19][20][21][22] has thus been chosen to simulate autoignition as previous studies have already shown its ability to catch such phenomenon [23]. This model is based on a look-up table of  i and  e , obtained using a priori calculations for the same surrogate fuel in homogeneous reactors and considering the LLNL kinetic mechanism with 1388 species and 5935 reactions [24].…”

Section: Numerical Set-upmentioning

confidence: 99%

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Detonation Peninsula for TRF-Air Mixtures: Assessment for the Analysis of Auto-Ignition Events in Spark-Ignition Engines

Guerouani¹,

Robert²,

Zaccardi³

2018

SAE Technical Paper Series

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Controlling abnormal auto-ignition processes in spark-ignition engines requires understanding how auto-ignition is triggered and how it propagates inside the combustion chamber. The original Zeldovich theory regarding auto-ignition propagation was further developed by Bradley and coworkers, who highlighted different modes by considering various hot spot characteristics and thermodynamic conditions around them. Dimensionless parameters (, ) were then proposed to classify these modes and to define a detonation peninsula for H 2-CO-air mixtures. This article deals with numerical simulations undertaken to check the relevancy of this original detonation peninsula when considering realistic gasoline fuels. 1D calculations of auto-ignition propagation are performed using the Tabulated Kinetics for Ignition model. Chemical kinetics calculations are first carried out to build the needed look-up table for the auto-ignition delay time  i , and the excitation times  e of E10-air mixtures using a RON 95 TRF surrogate. The dimensionless parameter is based on the hot spot radius and on the excitation time  e of the fuel. Previous chemical kinetics calculations confirm the impact of the fuel on this parameter as H 2-CO-air mixtures feature much longer excitation times than TRF-air mixtures. Focusing on the parameter  its estimation depends on hot spots characteristics and thermodynamic conditions. The limits of the peninsula therefore vary depending on initial conditions and hot spot characteristics, that is why this paper focuses on several conditions to validate the dependency of the boundaries between the different autoignition modes. Hundreds of simulations are performed and due to the large amount of calculations, a specific post-processing methodology is defined to determine the auto-ignition propagation modes by automatically characterizing the coupling conditions between reaction and pressure waves. Several new detonation peninsulas are finally proposed depending on initial conditions in terms of temperature, pressure, fuel-air equivalence ratio and dilution. Limits of the detonation peninsula for TRF-air mixtures are more affected depending on each operating conditions. These new limits can finally be used to better understand abnormal auto-ignition events in spark-ignition engines.

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Section: = 0 ⁄mentioning

confidence: 99%

Section: Numerical Set-upmentioning

confidence: 99%

Detonation Peninsula for TRF-Air Mixtures: Assessment for the Analysis of Auto-Ignition Events in Spark-Ignition Engines

Guerouani¹,

Robert²,

Zaccardi³

2018

SAE Technical Paper Series

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“…16–19 This approach allows to predict the local effects of fuel composition on flame propagation, autoignition and emission formation. The QD-SRM is already applied to investigate the effect of different octane number fuels on autoignition in the end gas as shown by Netzer et al 20 The detailed chemistry for multi-component fuels used in that work as well as in the presented work is based on the methodology of reaction mechanism development and reduction introduced by Seidel and colleagues. 21,22 The sensitivity of detailed chemistry for water injection is investigated in detail by Netzer et al 23 The authors separated the thermodynamic and chemical effects of water injection and showed how laminar flame speed, vaporization, heat capacity, chemical equilibrium, third-body reactions and ignition delay are influenced by water injection.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the detonation diagram is applied within the 0D framework to evaluate the autoignition in the end gas as an advanced method for analyzing knocking combustion. 20,28–30 The first section of this article introduces the fundamentals of the QD-SRM, the tabulated chemistry and the detonation diagram. Following, the experiments are outlined including measurements for direct water injection and the 1D-QD-SRM calibration is explained.…”

Section: Introductionmentioning

confidence: 99%

Gasoline engine performance simulation of water injection and low-pressure exhaust gas recirculation using tabulated chemistry

Franken

Mauß

Seidel³

et al. 2020

International Journal of Engine Research

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This work presents the assessment of direct water injection in spark-ignition engines using single cylinder experiments and tabulated chemistry-based simulations. In addition, direct water injection is compared with cooled low-pressure exhaust gas recirculation at full load operation. The analysis of the two knock suppressing and exhaust gas cooling methods is performed using the quasi-dimensional stochastic reactor model with a novel dual fuel tabulated chemistry model. To evaluate the characteristics of the autoignition in the end gas, the detonation diagram developed by Bradley and co-workers is applied. The single cylinder experiments with direct water injection outline the decreasing carbon monoxide emissions with increasing water content, while the nitrogen oxide emissions indicate only a minor decrease. The simulation results show that the engine can be operated at λ = 1 at full load using water–fuel ratios of up to 60% or cooled low-pressure exhaust gas recirculation rates of up to 30%. Both technologies enable the reduction of the knock probability and the decrease in the catalyst inlet temperature to protect the aftertreatment system components. The strongest exhaust temperature reduction is found with cooled low-pressure exhaust gas recirculation. With stoichiometric air–fuel ratio and water injection, the indicated efficiency is improved to 40% and the carbon monoxide emissions are reduced. The nitrogen oxide concentrations are increased compared to the fuel-rich base operating conditions and the nitrogen oxide emissions decrease with higher water content. With stoichiometric air–fuel ratio and exhaust gas recirculation, the indicated efficiency is improved to 43% and the carbon monoxide emissions are decreased. Increasing the exhaust gas recirculation rate to 30% drops the nitrogen oxide emissions below the concentrations of the fuel-rich base operating conditions.

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“…Recently, the authors suggested a method to predict engine knock using a quasi-dimensional stochastic reactor model. 30 In this work, we suggest a modeling tool chain that caters for the analysis of auto-ignition characteristics in the end gas as effect of fuel characteristics using 3D RANS simulations. The in-cylinder combustion is modeled using the level-set method 31 based on tabulated laminar flame speed combined with a well-stirred reactor model for the auto-ignition prediction in the end gas.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional computational fluid dynamics engine knock prediction and evaluation based on detailed chemistry and detonation theory

Netzer

Seidel

Pasternak

et al. 2017

International Journal of Engine Research

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Engine knock is an important phenomenon that needs consideration in the development of gasoline-fueled engines. In our days, this development is supported using numerical simulation tools to further understand and predict in-cylinder processes. In this work, a model tool chain which uses a detailed chemical reaction scheme is proposed to predict the auto-ignition behavior of fuels with different octane ratings and to evaluate the transition from harmless auto-ignitive deflagration to knocking combustion. In our method, the auto-ignition characteristics and the emissions are calculated using a gasoline surrogate reaction scheme containing pathways for oxidation of ethanol, toluene, n-heptane, iso-octane and their mixtures. The combustion is predicted using a combination of the G-equation based flame propagation model utilizing tabulated laminar flame speeds and well-stirred reactors in the burned and unburned zone in three-dimensional Reynolds-averaged Navier-Stokes. Based on the detonation theory by Bradley et al., the character and the severity of the auto-ignition event are evaluated. Using the suggested tool chain, the impact of fuel properties can be efficiently studied, the transition from harmless deflagration to knocking combustion can be illustrated and the severity of the autoignition event can be quantified.

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Engine Knock Prediction and Evaluation Based on Detonation Theory Using a Quasi-Dimensional Stochastic Reactor Model

Cited by 20 publications

References 39 publications

Detonation Peninsula for TRF-Air Mixtures: Assessment for the Analysis of Auto-Ignition Events in Spark-Ignition Engines

Detonation Peninsula for TRF-Air Mixtures: Assessment for the Analysis of Auto-Ignition Events in Spark-Ignition Engines

Gasoline engine performance simulation of water injection and low-pressure exhaust gas recirculation using tabulated chemistry

Three-dimensional computational fluid dynamics engine knock prediction and evaluation based on detailed chemistry and detonation theory

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