Spectral Analysis of Combustion Process of Common Rail Diesel Engine

2002 ◽  
Author(s):  
S. S. Merola ◽  
B. M. Vaglieco ◽  
F. E. Corcione ◽  
G. Formisano
Keyword(s):  
Spectral Analysis ◽  
Diesel Engine ◽  
Combustion Process ◽  
Common Rail

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

Visualization of the Effects of Post Injection and Swirl on the Combustion Process of a Passenger Car Common Rail DI Diesel Engine

2003 ◽  
Author(s):  
Arjan Helmantel ◽  
Joop Somhorst ◽  
Ingemar Denbratt
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Flame Temperature ◽  
Combustion Process ◽  
Small Diameter ◽  
Ccd Camera ◽  
Common Rail ◽  
Post Injection ◽  
Passenger Car ◽  
Di Diesel Engine

The effects of variations in injection strategy and swirl on a DI Diesel engine performance and emissions were tested. The cylinder head was fitted with a small diameter endoscope, coupled with a triggered CCD camera, in order to study the effect of these variations on the combustion process. The images that were taken of the combustion process were used to calculate the spatial and temporal distribution of flame temperature and soot kks factor by using the 2-color method. The engine used in the experiments is a single cylinder version of a modern, passenger car type, common rail Diesel engine with a displacement of 480 cc. The fitted endoscope caused very little interference with the combustion chamber due to its small dimensions. The 65 degree angle view of the endoscope allowed coverage of a large portion of the entire combustion chamber. The combustion images and derived temperatures and soot concentrations were used to study the influence of post injection and high swirl. Adding a third (post) injection to the pilot and main injection increases the mixing and the flame temperature during the second half of the combustion process, thereby improving soot oxidation. The fuel efficiency was not negatively affected by the later phasing of part of the heat release. Increased swirl of the intake air was also studied. An 80% increase in swirl-ratio was achieved by closing off one of the two intake ports with a butterfly valve. The improved mixing gave significant reductions in soot emissions, with a small increase in NOx formation.

Development of a Common Rail Diesel Engine Combustion Model for ROHR Real-Time Estimation

2011 ◽  
Author(s):  
Fabrizio Ponti ◽  
Vittorio Ravaglioli ◽  
Matteo De Cesare
Keyword(s):  
Diesel Engine ◽  
Real Time ◽  
Combustion Process ◽  
Time Estimation ◽  
Experimental Tests ◽  
Common Rail ◽  
Combustion Model ◽  
Combustion Control ◽  
Injection Parameters ◽  
Real Time Estimation

Combustion control is a crucial aspect in modern Diesel engines control strategies, mainly due to the requests to increase efficiency and maintain pollutant emissions within the values bounded by standard regulations. In order to perform an accurate combustion control, modern “closed loop” control algorithms require the evaluation of a large number of quantities that provide information about combustion process effectiveness. This work presents a methodology that allows real-time estimation of energy released, during the combustion process, in a Common Rail Multi-Jet Diesel engine. This procedure can be divided in two main steps. The first step consists in the development of a zero-dimensional combustion model based on the linear combination of a proper number of Wiebe functions. In this case, a zero-dimensional approach has been chosen, because it is accurate enough for this analysis and requires low computational efforts. Once the combustion model has been developed, it can be used to determine Rate of Heat Release (RoHR) and the angular position in which 50% of fuel burned within an engine cycle is reached (MFB50). The second section of this work describes the relationships existing between injection parameters (such as Start of Injection, injected fuel quantities, rail pressure...) and the Wiebe parameters identified in the first step of the procedure. The above mentioned relationships have been used to set up correlations that allow estimating Wiebe parameters, therefore ROHR and MFB50, starting from injection parameters. The results obtained in MFB50 estimation are particularly emphasized, because real-time knowledge of this quantity is necessary to feedback a control algorithm for optimal combustion positioning. This work is based on several experimental tests performed on a 2.2 liters Common Rail Multi-Jet Diesel engine. First, experimental tests have been carried out to identify the combustion model and the correlations existing between Wiebe parameters and injection parameters. Then, in order to determine the accuracy of the approach, the complete estimation methodology has been applied to the engine under study. This work describes a methodology for real-time estimation of several quantities that provide important information about combustion process effectiveness (useful, for example, in modern low temperature combustion control systems). No extra cost is needed, because the methodology requires no additional sensor.

A Phenomenological Combustion Model for Common Rail Multi-Jet Diesel Engine

2004 ◽  
Author(s):  
Fabrizio Ponti ◽  
Gabriele Serra ◽  
Carlo Siviero
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Angular Position ◽  
Combustion Process ◽  
Common Rail ◽  
Proper Function ◽  
Combustion Model ◽  
Number Of Injections ◽  
Engine Cycle ◽  
The Way

The simplest way to describe the combustion process into the cylinder of an internal combustion engine and the associated heat release is to estimate at each crankshaft angular position the mass fraction of fuel burned using a proper function. There is a number of functions recorded in the literature that have been used for this purpose, the most relevant being likely the so-called Wiebe function. These functions have been developed both for spark ignition and diesel engines. The development of modern Common Rail injection systems makes the application of this kind of methodology particularly challenging. The trend seems to indicate, in fact, that in the near future Diesel engine injection systems will perform up to five injections per engine cycle. Therefore the way energy is released into the cylinder could become very complex to be described and the simple approaches developed up to now could be not sufficient anymore. This paper deals with the development of a single zone combustion model able to correctly describe the heat release rate for a common rail multi-jet diesel engine employing up to 4 injections per engine cycle. The model has been developed step-by-step from the simplest case of a single injection to the more complex one with 4 injections. It has been identified and validated using experimental data obtained employing from 1 to 4 different injections. Premixed and diffusive combustions have been taken into account, both modelled as “Wiebe functions”. Particular identification problems (such as modelling error with multiple injection or identification robustness procedure) are approached on the basis of real data. The main result is that increasing the number of injections actuated (and then the combustion phases) predictive properties of the model are still acceptable, and identification procedure is robust if initial values of unknown parameters are properly set. The obtained results allowed observing for example the way the combustion delays (i.e the time delays between each Start of Injection and the corresponding Start of Combustion) are modified as the number of injections increases, as well as other important combustion characteristics.

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.

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