Investigation of the Effect of the In-Cylinder Tumble Motion on Cycle-to-Cycle Variations in a Direct Injection Spark Ignition (DISI) Engine Using Large Eddy Simulation (LES)

2016 ◽  
Vol 98 (2) ◽  
pp. 601-631 ◽  
Author(s):  
Wei Li ◽  
Yufeng Li ◽  
Tianyou Wang ◽  
Ming Jia ◽  
Zhizhao Che ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Direct Injection ◽  
Spark Ignition ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Direct Injection Spark Ignition

Large-eddy simulation analysis of knock in a direct injection spark ignition engine

2018 ◽  
Vol 20 (7) ◽  
pp. 765-776 ◽  
Author(s):  
Anthony Robert ◽  
Karine Truffin ◽  
Nicolas Iafrate ◽  
Stephane Jay ◽  
Olivier Colin ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Simulation Analysis ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Eddy Simulation ◽  
Oscillation Analysis ◽  
Spark Timing ◽  
Large Eddy ◽  
Direct Injection Spark Ignition

Downsized spark ignition engines running under high loads have become more and more attractive for car manufacturers because of their increased thermal efficiency and lower CO2 emissions. However, the occurrence of abnormal combustions promoted by the thermodynamic conditions encountered in such engines limits their practical operating range, especially in high efficiency and low fuel consumption regions. One of the main abnormal combustion is knock, which corresponds to an auto-ignition of end gases during the flame propagation initiated by the spark plug. Knock generates pressure waves which can have long-term damages on the engine, that is why the aim for car manufacturers is to better understand and predict knock appearance. However, an experimental study of such recurrent but non-cyclic phenomena is very complex, and these difficulties motivate the use of computational fluid dynamics for better understanding them. In the present article, large-eddy simulation (LES) is used as it is able to represent the instantaneous engine behavior and thus to quantitatively capture cyclic variability and knock. The proposed study focuses on the large-eddy simulation analysis of knock for a direct injection spark ignition engine. A spark timing sweep available in the experimental database is simulated, and 15 LES cycles were performed for each spark timing. Wall temperatures, which are a first-order parameter for knock prediction, are obtained using a conjugate heat transfer study. Present work points out that LES is able to describe the in-cylinder pressure envelope whatever the spark timing, even if the sample of LES cycles is limited compared to the 500 cycles recorded in the engine test bench. The influence of direct injection and equivalence ratio stratifications on combustion is also (MAPO) analyzed. Finally, focusing on knock, a Maximum Amplitude Pressure Oscillation analysis (MAPO) is conducted for both experimental and numerical pressure traces pointing out that LES well reproduces experimental knock tendencies.

Large-eddy simulation of the flow in a direct injection spark ignition engine using an open-source framework

2020 ◽  
pp. 146808742090362
Author(s):  
Mateus Dias Ribeiro ◽  
Alex Mendonça Bimbato ◽  
Maurício Araújo Zanardi ◽  
José Antônio Perrella Balestieri ◽  
David P Schmidt
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Large Eddy Simulation ◽  
Open Source ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Direct Injection Spark Ignition

Direct injection spark ignition engines aim at reducing specific fuel consumption and achieving the strict emission standards in state of the art internal combustion engines. This can be achieved by research comprising experimental methods, which are normally expensive and limited, and computational fluid dynamics methods, which are often more affordable and less restricted than their experimental counterpart. In the latter approach, the costs are mainly related to the acquisition, usage, and maintenance of computational resources, and the license cost when commercial computational fluid dynamics codes are used. Therefore, in order to make the research of direct injection spark ignition engines and their internal processes more accessible, this article proposes a novel open-source and free framework based on the OpenFOAM computational fluid dynamics library for the simulation of the internal flow in direct injection spark ignition engines using a large-eddy simulation closure for modeling the turbulence within the gas phase. Finally, this framework is tested by simulating the Darmstadt engine in motored operation, validating the results with experimental data compiled by the Darmstadt Engine Workshop.

scholarly journals Large-eddy spray simulation under direct-injection spark-ignition engine-like conditions with an integrated atomization/breakup model

2020 ◽  
pp. 146808741988186
Author(s):  
Hongjiang Li ◽  
Christopher J Rutland ◽  
Francisco E Hernández Pérez ◽  
Hong G Im
Keyword(s):  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Computational Domain ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Hybrid Breakup Model ◽  
Direct Injection Spark Ignition ◽  
Breakup Model ◽  
The Given

In this work, a hybrid breakup model tailored for direct-injection spark-ignition engine sprays is developed and implemented in the OpenFOAM CFD code. The model uses the Lagrangian–Eulerian approach whereby parcels of liquid fuel are injected into the computational domain. Atomization and breakup of the liquid parcels are described by two sub-models based on the breakup mechanisms reported in the literature. Evaluation of the model has been carried out by comparing large-eddy simulation results with experimental measurements under multiple direct-injection spark-ignition engine-like conditions. Spray characteristics including liquid and vapor penetration curves, droplet velocities, and Sauter mean diameter distributions are examined in detail. The model has been found to perform well for the spray conditions considered in this work. Results also show that after the end of injection, most of the residual droplets that are still in the breakup process are driven by the bag and bag–stamen breakup mechanisms. Finally, an effort to unify the breakup length parameter is made, and the given value is tested under various ambient density and temperature conditions. The predicted trends follow the measured data closely for the penetration rates, even though the model is not specifically tuned for individual cases.

Towards large eddy simulation of combustion in spark ignition engines

2007 ◽  
Vol 31 (2) ◽  
pp. 3059-3066 ◽  
Author(s):  
S. Richard ◽  
O. Colin ◽  
O. Vermorel ◽  
A. Benkenida ◽  
C. Angelberger ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Eddy Simulation ◽  
Large Eddy

Laminar-to-turbulent flame transition and cycle-to-cycle variations in large eddy simulation of spark-ignition engines

2020 ◽  
pp. 146808742096234
Author(s):  
Yunde Su ◽  
Derek Splitter ◽  
Seung Hyun Kim
Keyword(s):  
Large Eddy Simulation ◽  
Early Stage ◽  
Turbulent Flame ◽  
Transition Process ◽  
Spark Ignition ◽  
Transition Model ◽  
Flame Kernel ◽  
Eddy Simulation ◽  
Proposed Model ◽  
Large Eddy

This paper investigates the effect of laminar-to-turbulent flame transition modeling on the prediction of cycle-to-cycle variations (CCVs) in large eddy simulation (LES) of spark-ignition (SI) engines. A laminar-to-turbulent flame transition model that describes the non-equilibrium sub-filter flame speed evolution during an early stage of flame kernel growth is developed. In the present model, the flame transition is characterized by the flame kernel size at which the flame transition ends, defined here as the flame transition scale. The proposed model captures the effects that variations in a turbulent flow field have on the evolution of early-stage burning rates, through variations in the flame transition scale. The proposed flame transition model is combined with the front propagation formulation (FPF) method and a spark-ignition model to predict CCVs in a gasoline direct injection SI engine. It is found that multi-cycle LES with the proposed flame transition model reproduces experimentally-observed CCVs satisfactorily. When the transition model is not considered or when variations in the transition process are neglected, CCVs are significantly under-predicted for the case considered here. These results indicate the importance of modeling the laminar-to-turbulent flame transition and the effect of turbulence on the transition process, when predicting CCVs, under certain engine conditions. The LES results are also used to analyze sources for variations in the flame transition. It is found, for the present engine case, that the most important source is the cycle-to-cycle variation in the turbulence dissipation rate, which is used to measure the strength of turbulence in the proposed model, near a spark plug. The large-scale velocity field and the variations of the laminar flame speed due to the mixture composition and thermal stratification are also found to be important factors to contribute to the variations in the flame transition.

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