scholarly journals A Zero-Dimensional Combustion Model with Reduced Kinetics for SI Engine Knock Simulation

2009 ◽  
Vol 181 (6) ◽  
pp. 828-852 ◽  
Author(s):  
Zhen Liu ◽  
Rui Chen
Keyword(s):  
Combustion Model ◽  
Si Engine ◽  
Engine Knock

A Control-Oriented Reaction-Based SI Engine Combustion Model

2018 ◽  
Author(s):  
Ruixue C. Li ◽  
Guoming G. Zhu
Keyword(s):  
Chemical Reaction ◽  
Mass Fraction ◽  
Combustion Process ◽  
Combustion Model ◽  
Spark Ignition Engines ◽  
Si Engine ◽  
Chemical Reaction Mechanism ◽  
Engine Combustion ◽  
Rate Of Heat Release ◽  
Mass And Heat Transfer

This paper proposes a control-oriented chemical reaction-based two-zone combustion model designed to accurately describe the combustion process and thermal performance for spark-ignition engines. The combustion chamber is assumed to be divided into two zones: reaction and unburned zones, where the chemical reaction takes place in the reaction zone and the unburned zone contains all the unburned mixture. In contrast to the empirical pre-determined Wiebe-function-based combustion model, an ideal two-step chemical reaction mechanism is used to reliably model the detailed combustion process such as mass-fraction-burned (MFB) and rate of heat release. The interaction between two zones includes mass and heat transfer at the zone interface to have a smooth combustion process. This control-oriented model is extensively calibrated based on the experimental data to demonstrate its capability of predicting the combustion process and thermodynamic states of the in-cylinder mixture.

A Real-Time Pressure Wave Model for Predicting Engine Knock

2019 ◽  
Author(s):  
Ruixue C. Li ◽  
Guoming G. Zhu
Keyword(s):  
Pressure Wave ◽  
Time Pressure ◽  
Initial Conditions ◽  
Evaluation Criteria ◽  
Maximum Amplitude ◽  
Wave Model ◽  
Chemical Kinetic ◽  
Combustion Model ◽  
Pressure Oscillations ◽  
Engine Knock

Abstract This paper proposes a control-oriented pressure wave model, utilizing outputs of a reaction-based two-zone engine combustion model developed earlier, to accurately predict the key knock characteristics. The model can be used for model-based knock prediction and control. An in-cylinder pressure wave model of oscillation magnitude decay is proposed and simplified to describe pressure oscillations due to knock combustion, and the boundary and initial conditions of the pressure wave model at knock onset are provided by the two-zone reaction-based combustion model. The proposed pressure wave model is calibrated using experimental data, and the chemical kinetic-based Arrhenius integral (ARI) and maximum amplitude of pressure oscillations (MAPO) are used as the evaluation criteria for predicting knock onset and intensity, and the knock frequency is studied with the fast Fourier transform (FFT). The calibrated model is validated for predicting knock onset timing, knock intensity and frequency. Simulation results are compared with the experimental ones to demonstrate the capability of predicting engine knock characteristics by the proposed model.

A Control-Oriented Jet Ignition Combustion Model for an SI Engine

2015 ◽  
Author(s):  
Ruitao Song ◽  
Gerald Gentz ◽  
Guoming Zhu ◽  
Elisa Toulson ◽  
Harold Schock
Keyword(s):  
Combustion Chamber ◽  
Combustion Process ◽  
Turbulent Jets ◽  
Combustion Stability ◽  
Combustion Model ◽  
Combustion Chambers ◽  
Si Engine ◽  
Lean Operations ◽  
Combustion Processes ◽  
Hil Simulation

A turbulent jet ignition system of a spark ignited (SI) engine consists of pre-combustion and main-combustion chambers, where the combustion in the main-combustion chamber is initiated by turbulent jets of reacting products from the pre-combustion chamber. If the gas exchange and combustion processes are accurately controlled, the highly distributed ignition will enable very fast combustion and improve combustion stability under lean operations, which leads to high thermal efficiency, knock limit extension, and near zero NOx emissions. For model-based control, a precise combustion model is a necessity. This paper presents a control-oriented jet ignition combustion model, which is developed based on simplified fluid dynamics and thermodynamics, and implemented into a dSPACE based real-time hardware-in-the-loop (HIL) simulation environment. The two-zone combustion model is developed to simulate the combustion process in two combustion chambers. Correspondingly, the gas flowing through the orifices between two combustion chambers is divided into burned and unburned gases during the combustion process. The pressure traces measured from a rapid compression machine (RCM), equipped with a jet igniter, are used for initial model validation. The HIL simulation results show a good agreement with the experimental data.

scholarly journals Possibilities to identify engine combustion model parameters by analysis of the instantaneous crankshaft angular speed

2014 ◽  
Vol 18 (1) ◽  
pp. 97-112 ◽  
Author(s):  
Slobodan Popovic ◽  
Miroljub Tomic
Keyword(s):  
Combustion Process ◽  
Nonlinear Least Squares ◽  
Angular Speed ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Model Parameters ◽  
Si Engine ◽  
Engine Combustion ◽  
Novel Method ◽  
Engine Crankshaft

In this paper, novel method for obtaining information about combustion process in individual cylinders of a multi-cylinder Spark Ignition Engine based on instantaneous crankshaft angular velocity is presented. The method is based on robust box constrained Levenberg-Marquardt minimization of nonlinear Least Squares given for measured and simulated instantaneous crankshaft angular speed which is determined from the solution of the engine dynamics torque balance equation. Combination of in-house developed comprehensive Zero-Dimensional Two-Zone SI engine combustion model and analytical friction loss model in angular domain have been applied to provide sensitivity and error analysis regarding Wiebe combustion model parameters, heat transfer coefficient and compression ratio. The analysis is employed to evaluate the basic starting assumption and possibility to provide reliable combustion analysis based on instantaneous engine crankshaft angular speed.

Study of Cyclic Variation in an SI Engine Using Quasi-Dimensional Combustion Model

2007 ◽  
Author(s):  
E. Abdi Aghdam ◽  
A. A. Burluka ◽  
T. Hattrell ◽  
K. Liu ◽  
C. G. W. Sheppard ◽  
...  
Keyword(s):  
Combustion Model ◽  
Cyclic Variation ◽  
Si Engine

scholarly journals Prediction of Cyclic Variability and Knock-Limited Spark Advance (KLSA) in Spark-Ignition (SI) Engine

2018 ◽  
Author(s):  
Zongyu Yue ◽  
K. Dean Edwards ◽  
C. Scott Sluder ◽  
Sibendu Som
Keyword(s):  
Octane Number ◽  
Spark Ignition ◽  
Fuel Properties ◽  
Maximum Efficiency ◽  
Ignition Timing ◽  
Si Engine ◽  
Cfd Simulations ◽  
Chemical Kinetic Model ◽  
Cyclic Variability ◽  
Engine Knock

Engine knock remains one of the major barriers to further improve thermal efficiency of Spark Ignition (SI) engines. Knock can be suppressed by lowering the compression ratio, or retarding the spark ignition timing, however, at an expense of efficiency penalty. SI engine is usually operated at knock-limited spark advance (KLSA) to achieve possibly maximum efficiency with given engine hardware and fuel properties, such as Research Octane Number (RON), Motor Octane Number (MON), and heat of vaporization, etc. Co-optimization of engine design and fuel properties is promising to improve the engine efficiency and predictive CFD models can be used to facilitate this optimization process. However, difficulties exist in predicting KLSA in CFD simulations. First, cyclic variability of SI engine demands that multi-cycle results are required to capture the extreme conditions. Secondly, Mach Courant-Friedrichs-Lewy (CFL) number of 1 is desired to accurately predict the knock intensity (KI), resulting in unaffordable computational cost, especially for multi-cycle simulations. In this study, a new approach to numerically predict KLSA using large Mach CFL number of 50 is proposed. This approach is validated against experimental data for a boosted Direct Injection Spark Ignition (DISI) engine at multiple loads and spark timings. G-equation combustion model coupled with well-mixed chemical kinetic model are used to predict the turbulent flame propagation and end-gas auto-ignition, respectively. Simulations run for 10 consecutive engine cycles at each condition. The results show good agreement between model predictions and experiments in terms of cylinder pressure, combustion phasing and cyclic variation. Engine knock is predicted with early spark ignition timing, indicated by significant pressure wave oscillation and end-gas heat release. Maximum Amplitude of Pressure Oscillation (MAPO) analysis is performed to quantify the KI, and the slope change point in KI extrema is used to indicate the KLSA accurately. Using a smaller Mach CFL number of 5 also results in the same conclusions thus demonstrating that this approach is insensitive to the Mach CFL number. The use of large Mach CFL number allows us to achieve fast turn-around time for multi-cycle engine CFD simulations.

Optimization of a natural gas SI engine employing EGR strategy using a two-zone combustion model

Fuel ◽  
2008 ◽  
Vol 87 (10-11) ◽  
pp. 1824-1834 ◽  
Author(s):  
Amr Ibrahim ◽  
Saiful Bari
Keyword(s):  
Natural Gas ◽  
Combustion Model ◽  
Si Engine

scholarly journals Implementation and Parameter Analysis of the Knock Phenomenon of a Marine Dual-Fuel Engine Based on a Two-Zone Combustion Model

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 602
Author(s):  
Fang-Kun Zou ◽  
Hong Zeng ◽  
Huai-Yu Wang ◽  
Xin-Xin Wang ◽  
Zhao-Xin Xu
Keyword(s):  
Natural Gas ◽  
Air Temperature ◽  
Compression Ratio ◽  
Operating Parameter ◽  
Parameter Analysis ◽  
Combustion Model ◽  
Dual Fuel ◽  
Inlet Temperature ◽  
Dimensional Model ◽  
Engine Knock

The stable working window of a dual-fuel engine is narrow, and it is prone to knock during operation. The occurrence of knock limits the load and torque output of a dual-fuel engine, and even causes engine damage in severe cases. The existing volumetric model of marine dual-fuel engine has little research on the related problems of knock simulation. In order to analyze the causes of knock phenomenon and the influence of operating parameter changes on knock, under the Matlab/Simulink simulation environment, a quasi-dimensional model was established with MAN 8L51/60DF dual-fuel engine as the prototype, and the model was calibrated using the bench data. The knock intensity index coefficient (KI) was used as the evaluation index of knock intensity. Three parameters, the intake air temperature, compression ratio, and natural gas intake, were selected as variables to simulate the engine. According to the analysis of the simulation results, the influence of the parameter changes on the occurrence of engine knock phenomenon and knock intensity could be further studied. The results showed that the combination of the KI model and the quasi-dimensional model could effectively and accurately predict the engine performance and knock trend. The change of gas inlet quality, compression ratio, and inlet temperature could promote the occurrence of detonation, the engine knock could be avoided by controlling the intake air temperature below 336 K, compression ratio not exceeding 15 or the intake volume of natural gas per cycle not exceeding 11.25 g/cycle.

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