Analysis of Combustion Process in a Transparent Common Rail Diesel Engine by 2D Digital Imaging and Flame Emission Spectroscopy

2003 ◽  
Author(s):  
Simona S. Merola ◽  
Bianca M. Vaglieco ◽  
Ezio Mancaruso
Keyword(s):  
Diesel Engine ◽  
Digital Imaging ◽  
Emission Spectroscopy ◽  
Soot Formation ◽  
Combustion Process ◽  
Common Rail ◽  
Injection System ◽  
High Temporal Resolution ◽  
Oh Radicals ◽  
Flame Emission

Spectroscopic measurements and 2D digital imaging were used in single cylinder, four-stroke DI diesel engine, optically accessible. It was equipped with a four-valve head and fully flexible electronic controlled ‘Common Rail’ injection system. Three fuel injection strategies, descriptive of the CR diesel engine, were considered. They consisted of a main, a pilot and main and finally pilot, main and post injections. Fuel spray and visible flame propagation were evaluated by digital imaging at high temporal resolution. Autoignition and combustion processes were analysed by broadband ultraviolet-visible flame emission spectroscopy. Radical species such as OH and C2 allowed to characterise the ignition process and pollutant formation. Soot temperature and mass concentration were evaluated by two-colour pyrometry. The presence of C2 and OH radicals strongly characterised CR diesel combustion process during soot formation and evolution. In particular, the high presence of OH concentration for the whole process, from the autoignition to the soot formation and successive phases, contributed to lower the soot levels.

UV-Visible Emission Spectroscopy of the Combustion Process in a Common Rail Cl Engine Fulled with N-Butanol - Diesel Blends

2013 ◽  
Vol 390 ◽  
pp. 286-290 ◽  
Author(s):  
Cinzia Tornatore ◽  
Luca Marchitto ◽  
Simona Silvia Merola ◽  
Gerardo Valentino
Keyword(s):  
Emission Spectroscopy ◽  
Soot Formation ◽  
Combustion Process ◽  
Common Rail ◽  
Injection System ◽  
Optical Data ◽  
Spray Combustion ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Uv Visible

This paper is focused on the study of the effects of the injection strategy and fuel blends on spray combustion and soot formation in compression ignition engines. UV-visible natural emission spectroscopy was applied in the combustion chamber of a single cylinder high swirl compression ignition engine equipped with a common rail multi-jet injection system. The engine was fuelled with low-sulphur neat diesel and blended with 20 and 40% by volume of n-butanol. For all the fuels, the evolution of radical species, such like OH and soot was followed during the spray combustion processes examining different pilot-main dwell timings. Optical data were correlated to engine parameters and exhaust emissions.

Experimental Validation for Control-Oriented Modeling of Multi-Cylinder HCCI Diesel Engines

2006 ◽  
Author(s):  
Marcello Canova ◽  
Shawn Midlam-Mohler ◽  
Yann Guezennec ◽  
Giorgio Rizzoni ◽  
Luca Garzarella ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Injection System ◽  
Compression Ignition ◽  
Mixture Formation ◽  
Hcci Combustion

Homogeneous Charge Compression Ignition (HCCI) is a combustion process based on a lean, homogeneous, premixed charge reacting and burning uniformly throughout the mixture volume. This principle leads to a consistent decrease in NOx and PM emissions, while the combustion efficiency remains comparable to traditional Compression Ignition Direct Injection (CIDI) engines at low and mid-load operations. However, understanding and controlling the combustion process is still extremely difficult, as well as finding a proper method for the fuel introduction. A viable method consists of premixing the charge by applying a proper fuel atomization device in the intake port, thus decoupling the HCCI mixture formation from the traditional in-cylinder injection. This avoids the traditional drawbacks associated to external Diesel mixture preparation, such as high intake heating, low compression ratio, wall wetting, and soot formation. The system, previously developed and tested on a single-cylinder engine, has been successfully applied to multi-cylinder Diesel engine for automotive applications. Building on previous modeling and experimental work, the paper reports a detailed experimental analysis of HCCI combustion with external mixture formation. In the considered testing setup, the fuel atomizer has been applied to a four-cylinder turbo-charged Common Rail Diesel engine equipped with a cooled EGR system. In order to extend the knowledge on the process and to provide a large base of data for the identification of Control-Oriented Models, Diesel-fueled HCCI combustion has been characterized over different values of loads, EGR dilution and boost pressures. The data collected were then used for the validation of a HCCI Diesel engine model that was previously built for steady state and transient simulation and for control purposes. The experimental results obtained, especially considering the emission levels and efficiency, suggest that the technology developed for external mixture formation is a feasible upgrade for automotive Diesel engines without introducing additional design efforts or constraints on the DI combustion and injection system.

Characterisation of the Injection-Combustion Process in a Common Rail D.I. Diesel Engine Running with Sasol Fischer-Tropsch Fuel

2000 ◽  
Author(s):  
Francisco Payri ◽  
Jean Arrègle ◽  
Carlos Fenollosa ◽  
Gérard Belot ◽  
Alain Delage ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Common Rail ◽  
Fischer Tropsch

scholarly journals An Improved Soot Formation Model for 3D Diesel Engine Simulations

2006 ◽  
Vol 129 (3) ◽  
pp. 877-884 ◽  
Author(s):  
Joan Boulanger ◽  
Fengshan Liu ◽  
W. Stuart Neill ◽  
Gregory J. Smallwood
Keyword(s):  
Diesel Engine ◽  
Soot Formation ◽  
Computing Time ◽  
Combustion Process ◽  
Computational Cost ◽  
Wall Region ◽  
Soot Particles ◽  
Engine Combustion ◽  
Near Wall ◽  
Soot Model

Soot formation phenomenon is far from being fully understood today and models available for simulation of soot in practical combustion devices remain of relatively limited success, despite significant progresses made over the last decade. The extremely high demand of computing time of detailed soot models make them unrealistic for simulation of multidimensional, transient, and turbulent diesel engine combustion. Hence, most of the investigations conducted in real configuration such as multidimensional diesel engines simulation utilize coarse modeling, the advantages of which are an easy implementation and low computational cost. In this study, a phenomenological three-equation soot model was developed for modeling soot formation in diesel engine combustion based on considerations of acceptable computational demand and a qualitative description of the main features of the physics of soot formation. The model was developed based on that of Tesner et al. and was implemented into the commercial STAR-CD™ CFD package. Application of this model was demonstrated in the modeling of soot formation in a single-cylinder research version of Caterpillar 3400 series diesel engine with exhaust gas recirculation (EGR). Numerical results show that the new soot formulation overcomes most of the drawbacks in the existing soot models dedicated to this kind of engineering task and demonstrates a robust and consistent behavior with experimental observation. Compared to the existing soot models for engine combustion modeling, some distinct features of the new soot model include: no soot is formed at low temperature, minimal model parameter adjustment for application to different fuels, and there is no need to prescribe the soot particle size. At the end of expansion, soot is predicted to exist in two separate regions in the cylinder: in the near wall region and in the center part of the cylinder. The existence of soot in the near wall region is a result of reduced soot oxidation rate through heat loss. They are the source of the biggest primary particles released at the end of the combustion process. The center part of the cylinder is populated by smaller soot particles, which are created since the early stages of the combustion process but also subject to intense oxidation. The qualitative effect of EGR is to increase the size of soot particles as well as their number density. This is linked to the lower in-cylinder temperature and a reduced amount of air.

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