Evaluation of Modeling Approaches for NOx Formation in a Common-Rail DI Diesel Engine within the Framework of Representative Interactive Flamelets (RIF)

2008 ◽  
Author(s):  
C. Felsch ◽  
M. Gauding ◽  
A. Vanegas ◽  
H. Won ◽  
V. Luckhchoura ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Common Rail ◽  
Nox Formation ◽  
Modeling Approaches ◽  
Di Diesel Engine

The 2-Stroke DI-Diesel Engine with Common Rail Injection for Passenger Car Application

1998 ◽  
Author(s):  
J. Abthoff ◽  
F. Duvinage ◽  
T. Hardt ◽  
M. Krämer ◽  
M. Paule
Keyword(s):  
Diesel Engine ◽  
Common Rail ◽  
Passenger Car ◽  
Common Rail Injection ◽  
Di Diesel Engine

Detailed Evaluation of a New Semi-Empirical Two-Zone NOx Model by Application on Various Diesel Engine Configurations

2012 ◽  
Author(s):  
Stelios Provataris ◽  
Nicholas Savva ◽  
Dimitrios Hountalas
Keyword(s):  
Diesel Engine ◽  
Accurate Estimation ◽  
Operating Parameters ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Nox Formation ◽  
Light Duty ◽  
Physically Based ◽  
Di Diesel Engine ◽  
Semi Empirical

Over a significant period of time, efforts have been made towards a valid and accurate estimation of DI diesel engine NOx emissions. Considering the fact that experiments have a high cost in both time and money, modelling approaches have been developed in an effort to overcome these issues. It is well known that accuracy in the prediction of NOx emissions lies specifically on the accurate estimation of local temperature and O2 histories inside the combustion chamber that govern NOx formation, fulfilled by an accurate estimation of the combustion mechanism. To account for the actual effect of parameters that control NOx formation and overcome inefficiencies introduced from existing purely empirical models or artificial neural networks, valid only on the combustion systems for which they were developed [1], an alternative solution is the introduction of physically based semi-empirical models. Towards this direction, in the present work is presented and evaluated a new modelling approach, based on the combustion rate obtained from the measured cylinder pressure trace using Heat Release Rate Analysis. The model used is a semi-empirical two-zone one which makes use of the estimated elementary fuel mass burnt at each crank angle interval. The combustion process is considered to be adiabatic, while chemical dissociation is also considered. With this approach, temperature distribution throughout the combustion chamber is considered for, together with its evolution during the engine cycle. In addition, O2 availability is also considered for through the calculated charge composition. The result is an extremely fast computational model, combining the advantages of both empirical and physically based ones. In the present work is given a detailed validation of the model, from its application on two different types of diesel engines: a heavy-duty DI diesel engine and a light-duty DI diesel engine with pilot fuel injection. A significant number of cases where tested for both engine configurations, considering different operation points and variation of operating parameters, such as rail pressure and EGR. The twelve points of the European Stationary Cycle (ESC) were covered for the case of the heavy duty DI diesel engine, whilst for the light-duty DI engine a total number of forty-six operating points was studied. For both engine configurations the model reveals a very good predictive ability, considering for the effect of all operating parameters examined on NOx emissions. However, there is potential for improvement and development on its physical base for even more accurate predictions. The merits of good accuracy in prediction trends with varying engine operating parameters — even without calibration — and low computational time establish a potential for model use in engine development, optimization studies and model based control applications.

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.

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