Numerical modeling of combustion processes and pollutant formations in direct-injection diesel engines

2002 ◽  
Vol 16 (7) ◽  
Author(s):  
Seong-Ku Kim ◽  
Joon Kyu Lee ◽  
Yong-Mo Kim ◽  
Jae-Hyun Ahn
Keyword(s):  
Numerical Modeling ◽  
Diesel Engines ◽  
Direct Injection ◽  
Combustion Processes

Numerical Analysis of Swirl Chamber Combustion System in DI Diesel Engines with the Conical-Spray

2015 ◽  
Vol 752-753 ◽  
pp. 922-927
Author(s):  
Sheng Li Wei ◽  
Kun Peng Ji ◽  
Xian Yin Leng ◽  
Xuan Liu
Keyword(s):  
Diesel Engines ◽  
Direct Injection ◽  
Cone Angle ◽  
Combustion System ◽  
Combustion Chambers ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Swirl Chamber ◽  
Narrow Passage ◽  
Combustion Processes

In order to promote the quality of mixture and improve the fuel spray spatial distribution, enhancing airflow movement in a combustion chamber, a new swirl chamber combustion system in DI (direct injection) diesel engines is proposed based on conical-spray. Numerical simulations have been conducted by using the FIRE v2008 code. Several different widths of passage and spray angles are investigated in a single cylinder 135 diesel engine. The combustion and emissions performance were investigated by different conical-spray nozzles and combustion chambers with a constant compression ratio. The results show that using this combustion system, the mixture formation and combustion processes have been improved by a certain longitudinal swirl when the air is squished into the swirl chamber through the relative narrow passage. Moreover, the formation of homogeneous mixture is accelerated and the combustion is improved compared with that of conventional combustion system. The cases show the passage width of 5mm and conical spray cone angle of 140° has a better performance in the new combustion system.

Numerical Modeling of Combustion Processes and Pollutants Formation in Direct Injection Diesel Engine

2002 ◽  
Author(s):  
Hoo-Joong Kim ◽  
Nam-Il Heo ◽  
Yong-Mo Kim ◽  
Sung-Mo Kang ◽  
Jae-Hyun Ahn
Keyword(s):  
Numerical Modeling ◽  
Diesel Engine ◽  
Soot Formation ◽  
Direct Injection ◽  
Numerical Results ◽  
Nox Formation ◽  
Temperature Oxidation ◽  
Pollutant Formation ◽  
Direct Injection Diesel Engine ◽  
Combustion Processes

The Representative Interactive Flamelet (RIF) concept has been applied to numerically simulate the combustion processes and pollutant formation in the direct injection diesel engine. Due to the ability for interactively describing the transient behaviors of local flame structures with CFD solver, the RIF concept has the capabilities to predict the auto-ignition and subsequent flame propagation in the diesel engine combustion chamber as well as to effectively account for the detailed mechanisms of soot formation, NOx formation including thermal NO path, prompt and nitrous NOx formation, and reburning process. Special emphasis is given to the turbulent combustion model which properly accounts for vaporization effects on the mixture fraction fluctuations and the pdf model. The results of numerical modeling using the RIF concept are compared with experimental data and with numerical results of the commonly applied procedure which the low-temperature and high-temperature oxidation processes are represented by the Shell ignition model and the eddy dissipation model, respectively. Numerical results indicate that the RIF approach including the vaporization effect on turbulent spray combustion process successfully predicts the ignition delay time and location as well as the pollutant formation.

CFD Modeling of Pilot Injection and EGR in DI Diesel Engines

2004 ◽  
Author(s):  
Arturo de Risi ◽  
Teresa Donateo ◽  
Domenico Laforgia
Keyword(s):  
Shell Model ◽  
Diesel Engines ◽  
Direct Injection ◽  
Operating Conditions ◽  
Spray Angle ◽  
Cfd Modeling ◽  
Pilot Injection ◽  
Wide Range ◽  
Combustion Processes ◽  
Injection Strategies

The simulation of direct injection diesel engines requires accurate models to predict spray evolution and combustion processes. Several models have been proposed and widely tested for traditional injection strategies characterized by single injection pulse close to top dead center. Unfortunately, these models show some limits when applied to different injection strategies so that a correct simulation of engine performances and emission cannot be achieved without changing variables included in spray and combustion models. The aim of the present investigation is to improve the prediction capability of the KIVA3V code in case of pilot injection in order to use numerical simulations to define optimized pilot injection strategies. This goal was achieved by eliminating the hypotheses of constant fuel density and constant spray angle in the KIVA3V code and by using a modified version of the Shell model. The proposed modifications to the Shell model allow a better description of low temperature kinetics by the addition of two more radicals and three new kinetics reactions. The improvements in the code were verified by comparing experimental data and numerical results over a wide range of operating conditions including single injections, pilot injections and EGR.

A Comprehensive Simulation Model for Mixing and Combustion Characteristics of Small Direct Injection Diesel Engines

1995 ◽  
Vol 209 (2) ◽  
pp. 117-126 ◽  
Author(s):  
P S Mehta ◽  
S K Singal ◽  
B P Pundir
Keyword(s):  
Diesel Engines ◽  
Direct Injection ◽  
Droplet Size Distribution ◽  
Momentum Conservation ◽  
Integral Approach ◽  
Spray Structure ◽  
Model Predictions ◽  
Air Mixing ◽  
Combustion Processes ◽  
The Continuum

An analytical model has been developed to predict the fuel-air mixing and burning characteristics of small direct injection (DI) diesel engines. Four mass and momentum conservation equations are written along the tangential and normal directions to the spray for both free and wall regions based on the continuum integral approach. The spray structure is multi-zonal and the simulation of atomization, droplet-size distribution, evaporation, turbulent mixing and combustion processes is included. The model predictions show good correlation with the experimental data and respond well to the variations in input parameters. The level of predictions from the model is satisfactory and the model is quite suitable to optimize the injection characteristics bowl geometry and air motion in small DI diesel engines.

Effect of altitude conditions on combustion and performance of a turbocharged direct-injection diesel engine

2021 ◽  
pp. 095440702110262
Author(s):  
Zhentao Liu ◽  
Jinlong Liu
Keyword(s):  
Diesel Engine ◽  
High Altitude ◽  
Diesel Engines ◽  
Direct Injection ◽  
Pressure Rise ◽  
Ambient Conditions ◽  
Allowable Limit ◽  
Spray Formation ◽  
Direct Injection Diesel Engine ◽  
And Performance

Market globalization necessitates the development of heavy duty diesel engines that can operate at altitudes up to 5000 m without significant performance deterioration. But the current scenario is that existing studies on high altitude effects are still not sufficient or detailed enough to take effective measures. This study applied a single cylinder direct injection diesel engine with simulated boosting pressure to investigate the performance degradation at high altitude, with the aim of adding more knowledge to the literature. Such a research engine was conducted at constant speed and injection strategy but different ambient conditions from sea level to 5000 m in altitude. The results indicated the effects of altitude on engine combustion and performance can be summarized as two aspects. First comes the extended ignition delay at high altitude, which would raise the rate of pressure rise to a point that can exceed the maximum allowable limit and therefore shorten the engine lifespan. The other disadvantage of high-altitude operation is the reduced excess air ratio and gas density inside cylinder. Worsened spray formation and mixture preparation, together with insufficient and late oxidation, would result in reduced engine efficiency, increased emissions, and power loss. The combustion and performance deteriorations were noticeable when the engine was operated above 4000 m in altitude. All these findings support the need for further fundamental investigations of in-cylinder activities of diesel engines working at plateau regions.

Experimental facility and methodology for systematic studies of cold startability in direct injection Diesel engines

2009 ◽  
Vol 20 (9) ◽  
pp. 095109 ◽  
Author(s):  
J V Pastor ◽  
J M García-Oliver ◽  
J M Pastor ◽  
J G Ramírez-Hernández
Keyword(s):  
Diesel Engines ◽  
Direct Injection ◽  
Experimental Facility

The Development of 1.0 Liter and 1.4 Liter Three-Cylinder Direct-Injection Diesel Engines for Industrial Use

1989 ◽  
Author(s):  
Manabu Furubayashi ◽  
Eiichi Teramoto ◽  
Saburo Kase ◽  
Isao Konagaya ◽  
Kenichi Ueda ◽  
...  
Keyword(s):  
Diesel Engines ◽  
Direct Injection ◽  
Industrial Use
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