The Effects of Spray Angle and Piston Bowl Shape on Diesel Engine Soot Emissions Using 3-D CFD Simulation

2005 ◽  
Author(s):  
Jaeman Lim ◽  
Kyoungdoug Min
Keyword(s):  
Diesel Engine ◽  
Cfd Simulation ◽  
Spray Angle ◽  
Piston Bowl ◽  
Soot Emissions

A Computational Investigation of Piston Bowl Geometry for a Large Bore Two-Cycle Diesel Engine

2011 ◽  
Author(s):  
Jonathan Dolak ◽  
Deep Bandyopadhyay
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Simulation Software ◽  
Spray Angle ◽  
Tier 2 ◽  
Piston Bowl ◽  
Cylinder Test ◽  
Advanced Combustion ◽  
Combustion Simulation ◽  
Reduce Emissions

The objective of this research was to optimize an Electro-Motive Diesel (EMD) large-bore, two-cycle diesel engine (710 cubic inches of displacement per cylinder) at high load to minimize soot, nitrogen oxide (NOx) and fuel consumption. The variables considered were the number of spray-hole nozzles per injector, including spray angle and piston bowl geometry, for a range of injection pressures. Analytical simulations were conducted for a calibrated EMD 710 Tier 2 engine and a few of the top-performing cases were studied in detail. CONVERGE™, a commercially available, advanced combustion simulation software was used in this analysis. A surface deforming tool, Sculptor®, was used to obtain various piston bowl geometries. MiniTab® was utilized for statistical analysis. Results show that optimal combinations of injection variables and piston bowl shape exist to simultaneously reduce emissions and fuel consumption compared to Tier 2 EMD 710 engines. These configurations will be further tested in a single-cylinder test cell and presented later. This investigation shows the importance of bowl geometry and spray targeting on emissions and fuel consumption for large-bore, two-stroke engines with high power density.

Modelling and CFD Simulation of Effects of Spray Penetration on Piston Bowl Impingement in a DI Diesel Engine for Biodiesel-Diesel Blend (B20)

2012 ◽  
Author(s):  
Subhash Lahane ◽  
K. A. Subramanian
Keyword(s):  
Diesel Engine ◽  
Cfd Simulation ◽  
Injection Pressure ◽  
Spray Penetration ◽  
Penetration Distance ◽  
Piston Bowl ◽  
Fuel Jet ◽  
Wall Impingement ◽  
Di Diesel Engine ◽  
Nozzle Hole

The effect of spray penetration distance on fuel impingement on piston bowl of a 7.4 kW diesel engine for biodiesel-diesel blend (B20) was studied using modeling and CFD simulation. As the peak inline fuel pressure increased from 460 bar with base diesel to 480 bar with B20, the spray penetration distance (fuel jet) increases. It is observed from the study that the jet tip hits on piston bowl resulting to fuel impingement which is one of durability issues for use of biodiesel blend in the diesel engine. In addition to this, the simulation of effects of different injection pressures up to 2000 bar on spray penetration distance and wall impingement were also studied. The penetration distance increases with increase the in-line fuel pressure and it decreases with decrease nozzle hole diameter. The fuel impingement on piston bowl of the engine with high injection pressure (typically 1800 bar) can be avoided by decreasing the nozzle diameter from 0.19 mm to 0.1 mm. Increase in swirl ratio could also reduce fuel impingement problem.

scholarly journals Influence of narrow fuel spray angle and split injection strategies on combustion efficiency and engine performance in a common rail direct injection diesel engine

2016 ◽  
Vol 9 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Raouf Mobasheri
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Engine Performance ◽  
Spray Angle ◽  
Fuel Spray ◽  
Multiple Injection ◽  
Split Injection ◽  
Direct Injection Diesel Engine ◽  
Piston Bowl ◽  
Injection Strategies

Direct injection diesel engines have been widely used in transportation and stationary power systems because of their inherent high thermal efficiency. On the other hand, emission regulations such as NOx and particulates have become more stringent from the standpoint of preserving the environment in recent years. In this study, previous results of multiple injection strategies have been further investigated to analyze the effects of narrow fuel spray angle on optimum multiple injection schemes in a heavy duty common rail direct injection diesel engine. An advanced computational fluid dynamics simulation has been carried out on a Caterpillar 3401 diesel engine for a conventional part load condition in 1600 r/min at two exhaust gas recirculation rates. A good agreement of calculated and measured in-cylinder pressure, heat release rate and pollutant formation trends was obtained under various operating points. Three different included spray angles have been studied in comparison with the traditional spray injection angle. The results show that spray targeting is very effective for controlling the in-cylinder mixture distributions especially when it accompanied with various injection strategies. It was found that the optimum engine performance for simultaneous reduction of soot and NOx emissions was achieved with 105° included spray angle along with an optimized split injection strategy. The results show, in this case, the fuel spray impinges at the edge of the piston bowl and a counterclockwise flow motion is generated that pushes mixture toward the center of the piston bowl.

A CFD Study on Heavy Duty DI Diesel Engine to Achieve Ultra-Low Emissions

2010 ◽  
Author(s):  
M. Yilmaz ◽  
H. Koten ◽  
M. Zafer Gul
Keyword(s):  
Diesel Engine ◽  
Cfd Simulation ◽  
Combustion Engine ◽  
Direct Injection ◽  
Spray Angle ◽  
Combustion Model ◽  
Multiphase Model ◽  
Heavy Duty ◽  
Start Of Injection ◽  
Main Injection

Nowadays, automotive industries focused on clean diesel combustion in their combustion processes are investigated for their potential to achieve near zero particulate and NOx (Nitrogen oxides) emissions. Their main disadvantages are increased level of unburned hydrocarbons (HC) and carbon monoxide (CO) emissions, combustion control at high load, power output and limited operating range. The simulation of the air flow, spray and combustion in an internal combustion engine were prepared for a single cylinder of a nine-liter, six cylinder diesel engine. Many times the geometry is complex because moving pistons and valves are involved, which makes it difficult to generate structured mesh. In-cylinder spray-air motion interaction, a Lagrangian multiphase model has been applied in a heavy-duty CI engine under direct injection conditions. A comprehensive model for atomization of liquid sprays under high injection pressures has been employed. Three dimensional CFD calculations of the intake, compression and power strokes have been carried out with different spray angle, spray profile and start of injection. A new combustion model ECFM-3Z (Extended Coherent Flame Model) developed at IFP is used for combustion modeling. Finally, a calculation on an engine configuration with compression, spray injection and combustion in a direct injection Diesel engine is presented. In this study, exhaust emissions, and particularly the emission of NOx, CO and soot derived from premixed combustion are investigated, and the relationship between combustion and emission characteristics are showed. The calculated CFD simulation in different combustion cases was compared. The cases were prepared by changing the parameters: start of injection, spray angle and spray profile. Modeling of combustion proposed in the present study can be outlined as follows. NOx concentration is decreased by combustion of a over lean-mixture modeled by the pre-injection. Most of pre-mixture is combusted by main-injection, and therefore the amount of pre-injection and main-injection come into prominence. The results are greatly in agreement qualitatively with the previous experimental and computational studies in the literature.

High Efficiency Two-Valve DI Diesel Engine for Off-Road Application Complying With Upcoming Emission Limits

2012 ◽  
Author(s):  
Gian Marco Bianchi ◽  
Giulio Cazzoli ◽  
Claudio Forte ◽  
Marco Costa ◽  
Marcello Oliva
Keyword(s):  
Diesel Engine ◽  
Flow Field ◽  
High Efficiency ◽  
Nox Emission ◽  
Main Concern ◽  
Swirl Ratio ◽  
Emission Standard ◽  
Piston Bowl ◽  
Soot Emissions ◽  
Emission Limits

Nowadays, environmental concerns are posing a great challenge to DI Diesel engines. Increasingly tightening emission limits require a higher attention on combustion efficiency. In this scenario, computational fluid-dynamics can prove its power guaranteeing a deeper understanding of mixture formation process and combustion. A high efficiency Diesel engine can be developed only mastering all the parameters that can affect the combustion and, therefore, NOx and soot emissions. In this work, the development of an engine in order to fulfill Tier 4i emission standard will be presented. Originally, the engine was a two-valve engine supplied with a DPF. Since no SCR aftertreatment is supplied, NOx emission target are achieved through external exhaust gas recirculation and retarding the start of injection. In order to fulfill Tier 4i emissions, the main concern is on soot emission and, thus, the combustion chamber has been re-designed, through CFD simulations, leading to a better interaction between the flow field, the fuel spray and the piston bowl geometry. Particularly, through intake phase simulations, performed with the CFD code Fire v2009 v3, different intake ducts, with different swirl ratio, have been simulated in order to provide a flow field as realistic as possible for the combustion simulations. Through combustion process simulations, performed with the CFD code Kiva, by varying different parameters the interaction between the swirl flow field, generated by the intake duct, the reverse squish motion, and motions aerodynamically generated by spray has been investigated leading to the definition of a new engine lay-out. The study shows how, given the need of retarded injection for limiting NOx emission, the decrease of swirl ratio, when combined with a proper piston bowl design, allows a significant decrease of soot emissions and the achievement of Tier 4i emission standard.

scholarly journals Numerical investigation of injection parameters and piston bowl geometries on emission and thermal performance of DI diesel engine

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Ikhtedar Husain Rizvi ◽  
Rajesh Gupta
Keyword(s):  
Diesel Engine ◽  
Thermal Performance ◽  
Equivalence Ratio ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Injection Nozzle ◽  
Piston Bowl ◽  
Injection Parameters ◽  
Nozzle Size ◽  
Engine Emission

AbstractTightening noose on engine emission norms compelled manufacturers globally to design engines with low emission specially NOx and soot without compromising their performance. Amongst various parameters, shape of piston bowls, injection pressure and nozzle diameter are known to have significant influence over the thermal performance and emission emanating from the engine. This paper investigates the combined effect of fuel injection parameters such as pressure at which fuel is injected and the injection nozzle size along with shape of piston bowl on engine emission and performance. Numerical simulation is carried out using one cylinder naturally aspirated diesel engine using AVL FIRE commercial code. Three geometries of piston bowls with different tumble and swirl characteristics are considered while maintaining the volume of piston bowl, compression ratio, engine speed and fuel injected mass constant along with equal number of variations for injection nozzle size and pressures for this analysis. The investigation corroborates that high swirl and large turbulence kinetic energy (TKE) are crucial for better combustion. TKE and equivalence ratio also increased as the injection pressure increases during the injection period, hence, enhances combustion and reduces soot formation. Increase in nozzle diameter produces higher TKE and equivalence ratio, while CO and soot emission are found to be decreasing and NOx formation to be increasing. Further, optimization is carried out for twenty-seven cases created by combining fuel injection parameters and piston bowl geometries. The case D2H1P1 (H1 = 0.2 mm, P1 = 200 bar) found to be an optimum case because of its lowest emission level with slightly better performance.

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