scholarly journals Study on Premixed Combustion in a Diesel Engine with Ultra-multihole Nozzle

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
Xuelong Miao ◽  
Guiyang Zhang ◽  
Yusheng Ju ◽  
Xianyong Wang ◽  
Jian-hai Hong ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Combustion Chamber ◽  
Large Diameter ◽  
Premixed Combustion ◽  
Flow Area ◽  
Idle Speed ◽  
Volume Production ◽  
Soot Emissions ◽  
Large Flow

This study proposed a new low-temperature premixed combustion mode to achieve the simultaneous reduction of NOxand soot emissions in a volume production diesel engine of CA6DF by reconstructing key systems. Some developments of this diesel engine are as follows. A straight port and large diameter combustion chamber of a low compression ratio was developed. Inlet ports of a high induction swirl ratio were developed. A cooled EGR was developed. Especially, an ultra-multihole (UMH) nozzle was developed. It has two layers of injection holes and a large flow area. Two sprays of the upper and under layers meet in the space of the combustion chamber. The results showed that the operation range of this diesel engine to achieve the better low-temperature premixed combustion is as follows. The speed can cover from the idle speed to the rated speed. The load can reach to 50% of the full load of the corresponding external characteristics speed. The NOxand soot emissions of this operation range are simultaneously largely reduced, even by 80%–90% at most test cases, while keeping the brake-specific fuel consumption (BSFC) from being significantly deteriorated.

scholarly journals Modeling a fuel injector for a two-stroke diesel engine

2017 ◽  
Vol 170 (3) ◽  
pp. 147-153
Author(s):  
Rafał SOCHACZEWSKI ◽  
Zbigniew CZYŻ ◽  
Ksenia SIADKOWSKA
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Fuel Injection ◽  
Maximum Load ◽  
Fuel Injector ◽  
Dimensional Model ◽  
Flow Area ◽  
Fuel Mass ◽  
One Dimensional ◽  
Injector Nozzle

This paper discusses the modeling of a fuel injector to be applied in a two-stroke diesel engine. A one-dimensional model of a diesel injector was modeled in the AVL Hydsim. The research assumption is that the combustion chamber will be supplied with one or two spray injectors with a defined number of nozzle holes. The diameter of the nozzle holes was calculated for the defined options to provide a correct fuel amount for idling and the maximum load. There was examined the fuel mass per injection and efficient flow area. The studies enabled us to optimize the injector nozzle, given the option of fuel injection into the combustion chamber to be followed.

Study of Model-based Cooperative Control of EGR and VGT for a Low-temperature, Premixed Combustion Diesel Engine

2001 ◽  
Author(s):  
Takashi Shirawaka ◽  
Manabu Miura ◽  
Hiroyuki Itoyama ◽  
Eiji Aiyoshizawa ◽  
Shuji Kimura
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Cooperative Control ◽  
Premixed Combustion ◽  
Model Based

Applying the Representative Interactive Flamelet Model to Evaluate the Potential Effect of Wall Heat Transfer on Soot Emissions in a Small-Bore Direct-Injection Diesel Engine

2002 ◽  
Vol 124 (4) ◽  
pp. 1042-1052 ◽  
Author(s):  
C. Hergart ◽  
N. Peters
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Direct Injection ◽  
Particle Growth ◽  
Potential Effect ◽  
Two Phase ◽  
Flamelet Model ◽  
Detailed Chemistry ◽  
Direct Injection Diesel Engine ◽  
Soot Emissions

Capturing the physics related to the processes occurring in the two-phase flow of a direct-injection diesel engine requires a highly sophisticated modeling approach. The representative interactive flamelet (RIF) model has gained widespread attention owing to its ability of correctly describing ignition, combustion, and pollutant formation phenomena. This is achieved by incorporating very detailed chemistry for the gas phase as well as for the soot particle growth and oxidation, without imposing any significant computational penalty. This study addresses the part load soot underprediction of the model, which has been observed in previous investigations. By assigning flamelets, which are exposed to the walls of the combustion chamber, with heat losses calculated in a computational fluid dynamics (CFD) code, predictions of the soot emissions in a small-bore direct-injection diesel engine are substationally improved. It is concluded that the experimentally observed emissions of soot may have their origin in flame quenching at the relatively cold combustion chamber walls.

Simulation of Combustion and Emission Characteristics in a Dual Fuelled Diesel Engine

2010 ◽  
Author(s):  
Biplab K. Debnath ◽  
Bibhuti B. Sahoo ◽  
Ujjwal K. Saha ◽  
Niranjan Sahoo
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Combustion Velocity ◽  
Premixed Combustion ◽  
Dual Fuel ◽  
Combustion Modeling ◽  
Tetrahedral Elements ◽  
Constant Volume Combustion Chamber ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

In this paper, Computational Fluid Dynamics (CFD) approach is adopted to study the combustion and emission progression in a single cylinder four stroke diesel engine, operated in both diesel and dual-fuel modes. The study of dual-fuel mode is performed by using synthesis gas (syngas) with 75:25 and 50:50 volumetric combinations of hydrogen and carbon monoxide, respectively. The modeling and meshing of the constant volume combustion chamber is carried out by using GAMBIT tool. The meshing of the combustion chamber is performed using tetrahedral elements and the k–ε turbulence model is introduced along with non-premixed combustion modeling. The modeled hemispherical-piston-top combustion chamber is then simulated in FLUENT solver across the experimental boundary conditions at 40%, 60%, 80% and 100% of full load for both diesel and dual-fuel. The results of simulation incorporate the study of maximum combustion temperature, maximum combustion velocity and H2O mole fraction subsequent to combustion. Further, the concentrations of emissions have also been investigated for both diesel and dual-fuel modes. The results of simulations show a good agreement with the corresponding experimental data.

scholarly journals Optical Diagnostics of a Late Injection Low-Temperature Combustion in a Heavy Duty Diesel Engine

2007 ◽  
Author(s):  
Thierry Lachaux ◽  
Mark P. B. Musculus ◽  
Satbir Singh ◽  
Rolf D. Reitz
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Liquid Fuel ◽  
Premixed Combustion ◽  
Low Temperature Combustion ◽  
Heavy Duty ◽  
Cool Flame ◽  
Heavy Duty Diesel Engine ◽  
Temperature Combustion ◽  
Heavy Duty Diesel

A late injection, high exhaust-gas recirculation (EGR)-rate, low-temperature combustion strategy was investigated in a heavy-duty diesel engine using a suite of optical diagnostics: chemiluminescence for visualization of ignition and combustion, laser Mie scattering for liquid fuel imaging, planar laser-induced fluorescence (PLIF) for both OH and vapor-fuel imaging, and laser-induced incandescence (LII) for soot imaging. Fuel is injected at top dead center when the in-cylinder gases are hot and dense. Consequently, the maximum liquid fuel penetration is 27 mm, which is short enough to avoid wall impingement. The cool flame starts 4.5 crank angle degrees (CAD) after the start of injection (ASI), midway between the injector and bowl-rim, and likely helps fuel to vaporize. Within a few CAD, the cool-flame combustion reaches the bowl-rim. A large premixed combustion occurs near 9 CAD ASI, close to the bowl rim. Soot is visible shortly afterwards along the walls, typically between two adjacent jets at the head vortex location. OH PLIF indicates that premixed combustion first occurs within the jet and then spreads along the bowl rim in a thin layer, surrounding soot pockets at the start of the mixing-controlled combustion phase near 17 CAD ASI. During the mixing-controlled phase, soot is not fully oxidized and is still present near the bowl-rim late in the cycle. At the end of combustion near 27 CAD ASI, averaged PLIF images indicate two separate zones. OH PLIF appears near the bowl rim, while broadband PLIF persists late in the cycle near the injector. The most likely source of broadband PLIF is unburned fuel, which indicates that the near-injector region is a potential source of unburned hydrocarbons.

scholarly journals Optical Diagnostics of Late-Injection Low-Temperature Combustion in a Heavy-Duty Diesel Engine

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Thierry Lachaux ◽  
Mark P. B. Musculus ◽  
Satbir Singh ◽  
Rolf D. Reitz
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Liquid Fuel ◽  
Premixed Combustion ◽  
Low Temperature Combustion ◽  
Heavy Duty ◽  
Cool Flame ◽  
Heavy Duty Diesel Engine ◽  
Temperature Combustion ◽  
Heavy Duty Diesel

A late-injection, high exhaust-gas recirculation rate, low-temperature combustion strategy is investigated in a heavy-duty diesel engine using a suite of optical diagnostics: chemiluminescence for visualization of ignition and combustion, laser Mie scattering for liquid-fuel imaging, planar laser-induced fluorescence (PLIF) for both OH and vapor-fuel imagings, and laser-induced incandescence for soot imaging. Fuel is injected at top dead center when the in-cylinder gases are hot and dense. Consequently, the maximum liquid-fuel penetration is 27 mm, which is short enough to avoid wall impingement. The cool flame starts 4.5 crank angle degrees (CAD) after the start of injection (ASI), midway between the injector and bowl rim, and likely helps fuel to vaporize. Within a few CAD, the cool-flame combustion reaches the bowl rim. A large premixed combustion occurs near 9 CAD ASI, close to the bowl rim. Soot is visible shortly afterward, along the walls, typically between two adjacent jets. OH PLIF indicates that premixed combustion first occurs within the jet and then spreads along the bowl rim in a thin layer, surrounding soot pockets at the start of the mixing-controlled combustion phase near 17 CAD ASI. During the mixing-controlled phase, soot is not fully oxidized and is still present near the bowl rim late in the cycle. At the end of combustion near 27 CAD ASI, averaged PLIF images indicate two separate zones. OH PLIF appears near the bowl rim, while broadband PLIF persists late in the cycle near the injector. The most likely source of broadband PLIF is unburned fuel, which indicates that the near-injector region is a potential source of unburned hydrocarbons.

Influence of Key Structural Parameters of Combustion Chamber on the Performance of Diesel Engine

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Xinhai Li ◽  
Yong Cheng ◽  
Shaobo Ji ◽  
Xin Lan
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Dynamic Characteristics ◽  
Peak Pressure ◽  
Structural Parameters ◽  
Structural Parameter ◽  
Engine Combustion ◽  
Computational Fluid Dynamics Cfd ◽  
Soot Emissions ◽  
No Emissions

The structural parameters of combustion chamber have great impacts on the process of air–fuel mixing, combustion, and emissions of diesel engine. The dynamic characteristics and emission performances could be improved by means of optimizing the parameters of the combustion chamber. In this paper, the key structure of a diesel engine combustion chamber is parameterized, and the influence of individual structural parameter on dynamic characteristics and emissions of the engine is simulated and analyzed by computational fluid dynamics (CFD) software avl-fire. The results show that under constant compression ratio, the in-cylinder peak pressure decreases with increasing inclination angle of the combustion chamber (α), while the height (Tm) and bowl radius (R) have little influence on the in-cylinder peak pressure. With increasing α, NO emissions decrease, and soot emissions first increase and then decrease. With increasing R, both NO and soot emissions decrease first and then increase. Therefore, the combustion chamber parameters could be optimized by comprehensive consideration of cylinder pressure, NO and soot emissions.

Exhaust-Stream and In-Cylinder Measurements and Analysis of the Soot Emissions From a Common Rail Diesel Engine Using Two Fuels

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Patrick Kirchen ◽  
Peter Obrecht ◽  
Konstantinos Boulouchos ◽  
Andrea Bertola
Keyword(s):  
Diesel Engine ◽  
Soot Formation ◽  
Cetane Number ◽  
Combustion Process ◽  
Premixed Combustion ◽  
Aromatic Content ◽  
Kl Factor ◽  
Exhaust Stream ◽  
Soot Emissions ◽  
Operating Points

The operation and emissions of a four cylinder, passenger car common-rail diesel engine operating with two different fuels was investigated on the basis of exhaust-stream and in-cylinder soot measurements, as well as a thermodynamic analysis of the combustion process. The two fuels considered were a standard diesel fuel and a synthetic diesel (fuel two) with a lower aromatic content, evaporation temperature, and cetane number than the standard diesel. The exhaust-stream soot emissions, measured using a filter smoke number system, as well as a photo-acoustic soot sensor (AVL Micro Soot Sensor), were lower with the second fuel throughout the entire engine operating map. To elucidate the cause of the reduced exhaust-stream soot emissions, the in-cylinder soot temperature and the KL factor (proportional to concentration) were measured using miniature, three-color pyrometers mounted in the glow plug bores. Using the maximum KL factor value to quantify the soot formation process, it was seen that for all operating points, less soot was formed in the combustion chamber using the second fuel. The oxidation of the soot, however, was not strongly influenced by the fuel, as the relative oxidized soot fraction was not significantly different for the two fuels. The reduced soot formation of fuel two was attributed to the lower aromatic content of the fuel. The soot cloud temperatures for operation with the two fuels were not seen differ significantly. Similar correlations between the cylinder-out soot emissions, characterized using the pyrometers, and the exhaust-stream soot emissions were seen for both fuels. The combustion process itself was only seen to differ between the two fuels to a much lesser degree than the soot formation process. The predominant differences were seen as higher maximum fuel conversion rates during premixed combustion at several operating points, when fuel two was used. This was attributed to the lower evaporation temperatures and longer ignition delays (characterized by the lower cetane number) leading to larger premixed combustion fractions.

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