Heavy-Duty Diesel Combustion with Ultra-Low NOx and SOOT Emissions - A Comparison Between Experimental Data and CFD Simulations

2005 ◽  
Author(s):  
Tobias Husberg ◽  
Ingemar Denbratt ◽  
Monica Ringvik ◽  
Johan Engström
Keyword(s):  
Experimental Data ◽  
Diesel Combustion ◽  
Heavy Duty ◽  
Cfd Simulations ◽  
Soot Emissions ◽  
Heavy Duty Diesel

Numerical Investigation of Fuel Effects on Soot Emissions at Heavy-Duty Diesel Engine Conditions

2018 ◽  
Author(s):  
Meng Tang ◽  
Yuanjiang Pei ◽  
Yu Zhang ◽  
Michael Traver ◽  
David Cleary ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Turbulence Model ◽  
Soot Formation ◽  
Heavy Duty ◽  
Cfd Simulations ◽  
Heavy Duty Diesel Engine ◽  
Soot Emissions ◽  
Heavy Duty Diesel ◽  
Lift Off ◽  
Soot Model

Gasoline compression ignition (GCI) engine technology has shown the potential to achieve high fuel efficiency with low criteria pollutant emissions. In order to guide the design and optimization of GCI combustion, it is essential to develop high-fidelity simulation tools. Building on the previous work in computational fluid dynamic (CFD) simulations of spray combustion, this work focuses on predicting the soot emissions in a constant-volume vessel representative of heavy-duty diesel engine applications for an ultra-low sulfur diesel (ULSD) and a high reactivity (Research Octane Number 60) gasoline, and comparing the soot evolution characteristics of the two fuels. Simulations were conducted using both Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) turbulence models. Extensive model validations were performed against the experimental soot emissions data for both fuels. It was found that the simulation results using the LES turbulence model agreed better with the measured ignition delays and liftoff lengths than the RANS turbulence model. In addition, two soot models were evaluated in the current study, including an empirical two-step soot formation and oxidation model, and a detailed soot model that involves poly-aromatic hydrocarbon (PAH) chemistry. Validations showed that the separation of the flame lift-off location and the soot lift-off location and the relative natural luminosity signals were better predicted by the detailed soot model combined with the LES turbulence model. Qualitative comparisons of simulated local soot concentration distributions against experimental measurements in the literature confirmed the model’s performance. CFD simulations showed that the transition of domination from soot formation to soot oxidation was fuel-dependent, and the two fuels exhibited different temporal and spatial characteristics of soot emissions. CFD simulations also confirmed the lower sooting propensity of gasoline compared to ULSD under all investigated conditions.

scholarly journals An Improved Phenomenological Soot Formation Submodel for Three-Dimensional Diesel Engine Simulations: Extension to Agglomeration of Particles into Clusters

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Joan Boulanger ◽  
W. Stuart Neill ◽  
Fengshan Liu ◽  
Gregory J. Smallwood
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Oxidation Process ◽  
Soot Formation ◽  
Three Dimensional ◽  
Soot Oxidation ◽  
Heavy Duty ◽  
Heavy Duty Diesel Engine ◽  
Agglomeration Effects ◽  
Heavy Duty Diesel

An extension to a phenomenological submodel for soot formation to include soot agglomeration effects is developed. The improved submodel was incorporated into a commercial computational fluid dynamics code and was used to investigate soot formation in a heavy-duty diesel engine. The results of the numerical simulation show that the soot oxidation process is reduced close to the combustion chamber walls, due to heat loss, such that larger soot particles and clusters are predicted in an annular volume at the end of the combustion cycle. These results are consistent with available in-cylinder experimental data and suggest that the cylinder of a diesel engine must be split into several volumes, each of them with a different role regarding soot formation.

Fuel Property Effects on PCCI Combustion in a Heavy-Duty Diesel Engine

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Cosmin E. Dumitrescu ◽  
W. Stuart Neill ◽  
Hongsheng Guo ◽  
Vahid Hosseini ◽  
Wallace L. Chippior
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Cetane Number ◽  
Injection System ◽  
Injection Timing ◽  
Heavy Duty ◽  
Fuel Property ◽  
Heavy Duty Diesel Engine ◽  
Soot Emissions ◽  
Heavy Duty Diesel

An experimental study was performed to investigate fuel property effects on premixed charge compression ignition (PCCI) combustion in a heavy-duty diesel engine. A matrix of research diesel fuels designed by the Coordinating Research Council, referred to as the Fuels for Advanced Combustion Engines (FACE), was used. The fuel matrix design covers a wide range of cetane numbers (30 to 55), 90% distillation temperatures (270 to 340 °C) and aromatics content (20 to 45%). The fuels were tested in a single-cylinder Caterpillar diesel engine equipped with a common-rail fuel injection system. The engine was operated at 900 rpm, a relative air/fuel ratio of 1.2 and 60% exhaust gas recirculation (EGR) for all fuels. The study was limited to a single fuel injection event starting between −30° and 0 °CA after top dead center (aTDC) with a rail pressure of 150 MPa. The brake mean effective pressure (BMEP) ranged from 2.6 to 3.1 bar depending on the fuel and its injection timing. The experimental results show that cetane number was the most important fuel property affecting PCCI combustion behavior. The low cetane number fuels had better brake specific fuel consumption (BSFC) due to more optimized combustion phasing and shorter combustion duration. They also had a longer ignition delay period available for premixing, which led to near-zero soot emissions. The two fuels with high cetane number and high 90% distillation temperature produced significant soot emissions. The two fuels with high cetane number and high aromatics produced the highest brake specific NOx emissions, although the absolute values were below 0.1 g/kW-h. Brake specific HC and CO emissions were primarily a function of the combustion phasing, but the low cetane number fuels had slightly higher HC and lower CO emissions than the high cetane number fuels.

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