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Global Sensitivity Analysis of a Gasoline Compression Ignition Engine Simulation with Multiple Targets on an IBM Blue Gene/Q Supercomputer

Argonne National Laboratory-Janardhan Kodavasal, Yuanjiang Pei, Kevin Harms, Stephen Ciatti, Al Wagner, Marta García, Sibendu Som
Convergent Science, Inc.-Peter Senecal
Published 2016-04-05 by SAE International in United States
In internal combustion engine computational fluid dynamics (CFD) simulations, uncertainties arise from various sources, such as estimates of model parameters, experimental boundary conditions, estimates of chemical kinetic rates, etc. These uncertainties propagate through the model and may result in discrepancies compared to experimental measurements. The relative importance of the various sources of uncertainty can be quantified by performing a sensitivity analysis. In this work, global sensitivity analysis (GSA) was applied to engine CFD simulations of a low-temperature combustion concept called gasoline compression ignition, to understand the influence of experimental measurement uncertainties from various sources on specific targets of interest-spray penetration, ignition timing, combustion phasing, combustion duration, and emissions. The sensitivity of these targets was evaluated with respect to imposed uncertainties in experimental boundary conditions and fuel properties. In the present study, the sensitivity of the targets to uncertainties in CFD model parameters and chemical kinetic rates was not studied. Closed-cycle CFD simulations were performed using a 1/7th cylinder sector mesh representative of a four-cylinder, 1.9 L, multi-cylinder diesel engine modified to run on gasoline, under…
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Achieving Stable Engine Operation of Gasoline Compression Ignition Using 87 AKI Gasoline Down to Idle

Argonne National Laboratory-Christopher Kolodziej, Janardhan Kodavasal, Stephen Ciatti, Sibendu Som, Neeraj Shidore, Jeremy Delhom
Published 2015-04-14 by SAE International in United States
For several years there has been a great deal of effort made in researching ways to run a compression ignition engine with simultaneously high efficiency and low emissions. Recently much of this focus has been dedicated to using gasoline-like fuels that are more volatile and less reactive than conventional diesel fuel to allow the combustion to be more premixed. One of the key challenges to using fuels with such properties in a compression ignition engine is stable engine operation at low loads. This paper provides an analysis of how stable gasoline compression ignition (GCI) engine operation was achieved down to idle speed and load on a multi-cylinder compression ignition engine using only 87 anti-knock index (AKI) gasoline. The variables explored to extend stable engine operation to idle included: uncooled exhaust gas recirculation (EGR), injection timing, injection pressure, and injector nozzle geometry. The results of three-dimensional computational fluid dynamics engine combustion simulations revealed the importance of retaining sufficient local richness and stratification of the fuel-air mixture centered in the piston bowl for stable ignition and combustion…
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Computational Investigation of Low Load Operation in a Light-Duty Gasoline Direct Injection Compression Ignition [GDICI] Engine Using Single-Injection Strategy

Argonne National Lab.-Stephen Ciatti, Christopher Kolodziej
Univ. of Wisconsin-Bishwadipa Das Adhikary, Rolf D. Reitz
Published 2014-04-01 by SAE International in United States
The use of gasoline in a compression ignition engine has been a research focus lately due to the ability of gasoline to provide more premixing, resulting in controlled emissions of the nitrogen oxides [NOx] and particulate matter. The present study assesses the reactivity of 93 RON [87AKI] gasoline in a GM 1.9L 4-cylinder diesel engine, to extend the low load limit. A single injection strategy was used in available experiments where the injection timing was varied from −42 to −9 deg ATDC, with a step-size of 3 deg. The minimum fueling level was defined in the experiments such that the coefficient of variance [COV] of indicated mean effective pressure [IMEP] was less than 3%. The study revealed that injection at −27 deg ATDC allowed a minimum load of 2 bar BMEP. Also, advancement in the start of injection [SOI] timing in the experiments caused an earlier CA50, which became retarded with further advancement in SOI timing. To help explain these behaviors, simulations were carried out using the KIVA3V CFD code coupled with a Jacobian chemistry…
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Extension of the Lower Load Limit of Gasoline Compression Ignition with 87 AKI Gasoline by Injection Timing and Pressure

Argonne National Lab.-Christopher P. Kolodziej, Stephen Ciatti
Univ. of California-David Vuilleumier
Published 2014-04-01 by SAE International in United States
Previous work has demonstrated the capabilities of gasoline compression ignition to achieve engine loads as high as 19.5 bar BMEP with a production multi-cylinder diesel engine using gasoline with an anti-knock index (AKI) of 87. In the current study, the low load limit of the engine was investigated using the same engine hardware configurations and 87 AKI fuel that was used to achieve 19.5 bar BMEP. Single injection, “minimum fueling” style injection timing and injection pressure sweeps (where fuel injection quantity was reduced at each engine operating condition until the coefficient of variance of indicated mean effective pressure rose to 3%) found that the 87 AKI test fuel could run under stable combustion conditions down to a load of 1.5 bar BMEP at an injection timing of −30 degrees after top dead center (°aTDC) with reduced injection pressure, but still without the use of intake air heating or uncooled EGR. A 0.4% concentration (by volume) of 2-Ethylhexyl Nitrate (EHN) was added to the 87 AKI test fuel to test the effects of increased reactivity on…
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Efficiency and Emissions performance of Multizone Stratified Compression Ignition Using Different Octane Fuels

Argonne National Laboratory-Stephen Ciatti, Michael Johnson
Columbia University-Aaron Knock
Published 2013-04-08 by SAE International in United States
Advanced combustion systems that simultaneously address PM and NOx while retaining the high efficiency of modern diesel engines, are being developed around the globe. One of the most difficult problems in the area of advanced combustion technology development is the control of combustion initiation and retaining power density. During the past several years, significant progress has been accomplished in reducing emissions of NOx and PM through strategies such as LTC/HCCI/PCCI/PPCI and other advanced combustion processes; however control of ignition and improving power density has suffered to some degree - advanced combustion engines tend to be limited to the 10 bar BMEP range and under.Experimental investigations have been carried out on a light-duty DI multi-cylinder diesel automotive engine. The engine is operated in low temperature combustion (LTC) mode using 93 RON (Research Octane Number) and 74 RON fuel. The presented approach uses multiple injections of low cetane (gasoline-like) fuels in a Multizone, Stratified Compression Ignition (MSCI) approach in an effort to improve control of combustion phasing and increase the engine load such that the practicality of…
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Study of In-Cylinder Combustion and Multi-Cylinder Light Duty Compression Ignition Engine Performance Using Different RON Fuels at Light Load Conditions

Argonne National Laboratory-Stephen Ciatti
Univ of Wisconsin-Madison-Rolf D. Reitz
Published 2013-04-08 by SAE International in United States
The effects of different Research Octane Number [RON] fuels on a multi-cylinder light-duty compression ignition [CI] engine were investigated at light load conditions. Experiments were conducted on a GM 1.9L 4-cylinder diesel engine at Argonne National Laboratory, using two different fuels, i.e., 75 RON and 93 RON.Emphasis was placed on 5 bar BMEP load, 2000 rev/min engine operation using two different RON fuels, and 2 bar BMEP load operating at 1500 rev/min using 75 RON gasoline fuel. The experiments reveal difficulty in controlling combustion at low load points using the higher RON fuel. In order to explain the experimental trends, simulations were carried out using the KIVA3V-Chemkin Computational Fluid Dynamics [CFD] Code. The numerical results were validated with the experimental results and provided insights about the engine combustion characteristics at different speeds and low load conditions using different fuels. It was observed that cycle-to-cycle and cylinder-to-cylinder variability issues complicate the multi-cylinder engine operation to a significant extent. Effective compression ratios [CR] of all 4 cylinders were found to be different, which indicates the variability in…
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Numerical Optimization of a Light-Duty Compression Ignition Engine Fuelled With Low-Octane Gasoline

Bishwadipa Das Adhikary
Argonne National Laboratory-Stephen Ciatti
Published 2012-04-16 by SAE International in United States
In automotive industry it has been a challenge to retain diesel-like thermal efficiency while maintaining low emissions. Numerous studies have shown significant progress in achieving low emissions through the introduction of common-rail injection systems, multiple injections and exhaust gas recirculation and by using a high octane number fuel, like gasoline, to achieve adequate premixing. On the other hand, low temperature combustion strategies, like HCCI and PCCI, have also shown promising results in terms of reducing both NOx and soot emissions simultaneously. With the increasing capacity of computers, multi-dimensional CFD engine modeling enables a reasonably good prediction of combustion characteristics and pollutant emissions, which is the motivation behind the present research. The current research effort presents an optimization study of light-duty compression ignition engine performance, while meeting the emission regulation targets. A numerical optimization study was carried out on a light-duty, single-cylinder, compression ignition engine, fueled with a PRF87 gasoline surrogate, at a full load operating condition. The simulations were performed using a Non-dominated Sorting Genetic Algorithm II (NSGAII) code coupled to a multi-dimensional CFD code,…
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Investigation of Injection Parameters in a Hydrogen DI Engine Using an Endoscopic Access to the Combustion Chamber

Argonne National Laboratory-Thomas Wallner, Stephen Ciatti, Bipin Bihari
Published 2007-04-16 by SAE International in United States
In order to achieve the targets for hydrogen engines set by the U.S. Department of Energy (DOE) - a brake thermal efficiency of 45% and nitrogen oxide (NOx) emissions below 0.07 g/mi - while maintaining the same power density as comparable gasoline engines, researchers need to investigate advanced mixture formation and combustion strategies for hydrogen internal combustion engines.Hydrogen direct injection is a very promising approach to meeting DOE targets; however, there are several challenges to be overcome in order to establish this technology as a viable pathway toward a sustainable hydrogen infrastructure.This paper describes the use of endoscopic imaging as a diagnostic tool that allows further insight into the processes that occur during hydrogen combustion. It also addresses recent progress in the development of advanced direct-injected hydrogen internal combustion engine concepts.Our paper characterizes the hydrogen combustion behavior in a single-cylinder research engine and provides an analysis of the results of hydrogen direct-injection operation. Unlike conventional combustion analysis, which employs pressure traces and derived information (e.g., rate of heat release), the combustion characterization in this study…
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Sizes, Graphitic Structures and Fractal Geometry of Light-Duty Diesel Engine Particulates

Kyeong Ook Lee, Jinyu Zhu, Stephen Ciatti, Ahmet Yozgatligil, Mun Young Choi
Published 2003-10-27 by SAE International in United States
The particulate matter of a light-duty diesel engine was characterized in its morphology, sizes, internal microstructures, and fractal geometry. A thermophoretic sampling system was employed to collect particulates directly from the exhaust manifold of a 1.7-liter turbocharged common-rail direct-injection diesel engine. The particulate samples collected at various engine-operating conditions were then analyzed by using a high-resolution transmission electron microscope (TEM) and an image processing/data acquisition system. Results showed that mean primary particle diameters (dp), and radii of gyration (Rg), ranged from 19.4 nm to 32.5 nm and 77.4 nm to 134.1 nm, respectively, through the entire engine-operating conditions of 675 rpm (idling) to 4000 rpm and 0% to 100% loads. It was also revealed that the other important parameters sensitive to the particulate formation, such as exhaust-gas recirculation (EGR) rate, equivalence ratio, and temperature, affected particle sizes significantly. Bigger primary particles were measured at higher EGR rates, higher equivalence ratios (fuel-rich), and lower exhaust temperatures. Fractal dimensions (Df) were measured at a range of 1.5 ∼ 1.7, which are smaller than those measured for heavy-duty…
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