Soot Formation and Oxidation in Diesel Engines

1980 ◽  
Author(s):  
H. Hiroyasu ◽  
M. Arai ◽  
K. Nakanishi
Keyword(s):  
Diesel Engines ◽  
Soot Formation

scholarly journals Possibilities of Simultaneous In-Cylinder Reduction of Soot andNOxEmissions for Diesel Engines with Direct Injection

2008 ◽  
Vol 2008 ◽  
pp. 1-13 ◽  
Author(s):  
U. Wagner ◽  
P. Eckert ◽  
U. Spicher
Keyword(s):  
Nitrogen Oxide ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Soot Formation ◽  
Soot Oxidation ◽  
The Other ◽  
Injection System ◽  
Nitrogen Oxide Emissions ◽  
Injection Strategy ◽  
Soot Emissions

Up to now, diesel engines with direct fuel injection are the propulsion systems with the highest efficiency for mobile applications. Future targets in reducingCO2-emissions with regard to global warming effects can be met with the help of these engines. A major disadvantage of diesel engines is the high soot and nitrogen oxide emissions which cannot be reduced completely with only engine measures today. The present paper describes two different possibilities for the simultaneous in-cylinder reduction of soot and nitrogen oxide emissions. One possibility is the optimization of the injection process with a new injection strategy the other one is the use of water diesel emulsions with the conventional injection system. The new injection strategy for this experimental part of the study overcomes the problem of increased soot emissions with pilot injection by separating the injections spatially and therefore on the one hand reduces the soot formation during the early stages of the combustion and on the other hand increases the soot oxidation later during the combustion. Another method to reduce the emissions is the introduction of water into the combustion chamber. Emulsions of water and fuel offer the potential to simultaneously reduceNOxand soot emissions while maintaining a high-thermal efficiency. This article presents a theoretical investigation of the use of fuel-water emulsions in DI-Diesel engines. The numerical simulations are carried out with the 3D-CFD code KIVA3V. The use of different water diesel emulsions is investigated and assessed with the numerical model.

Quasidimensional Modeling of Direct Injection Diesel Engine Nitric Oxide, Soot, and Unburned Hydrocarbon Emissions

2005 ◽  
Vol 128 (2) ◽  
pp. 388-396 ◽  
Author(s):  
Dohoy Jung ◽  
Dennis N. Assanis
Keyword(s):  
Nitric Oxide ◽  
Diesel Engine ◽  
Diesel Engines ◽  
Soot Formation ◽  
Direct Injection ◽  
Equation Model ◽  
Design Tool ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Cycle Simulation

In this study we report the development and validation of phenomenological models for predicting direct injection (DI) diesel engine emissions, including nitric oxide (NO), soot, and unburned hydrocarbons (HC), using a full engine cycle simulation. The cycle simulation developed earlier by the authors (D. Jung and D. N. Assanis, 2001, SAE Transactions: Journal of Engines, 2001-01-1246) features a quasidimensional, multizone, spray combustion model to account for transient spray evolution, fuel–air mixing, ignition and combustion. The Zeldovich mechanism is used for predicting NO emissions. Soot formation and oxidation is calculated with a semiempirical, two-rate equation model. Unburned HC emissions models account for three major HC sources in DI diesel engines: (1) leaned-out fuel during the ignition delay, (2) fuel yielded by the sac volume and nozzle hole, and (3) overpenetrated fuel. The emissions models have been validated against experimental data obtained from representative heavy-duty DI diesel engines. It is shown that the models can predict the emissions with reasonable accuracy. Following validation, the usefulness of the cycle simulation as a practical design tool is demonstrated with a case study of the effect of the discharge coefficient of the injector nozzle on pollutant emissions.

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