scholarly journals Numerical Simulation of the Effect of Post Injection on SOOT Formation in a DI Diesel Engine Using CFD

Author(s):  
Moses Aravind
Author(s):  
Kamran Poorghasemi ◽  
Fathollah Ommi ◽  
Vahid Esfahanian

In DI Diesel engines NO and Soot trade off is an important challenge for Engineers. In this paper, at first, multiple injection strategy will be introduced as a useful way to reduce both NO and Soot emissions simultaneously. Then the effect of injection pressure in post injection on the engine emissions will be studied. Investigations have been conducted on DI diesel engine. To evaluate the benefits of multiple injection strategies and to reveal combustion mechanism, modified three dimensional CFD code KIVA-3V was used. Results showed that using post injection with appropriate dwell between injection pulses can be effective in simultaneously reduction of emissions. Based on computation results, NO reduction formation mechanism is a single injection with retarded injection timing. It is shown that reduced soot formation is because of the fact that the soot producing rich regions at the fuel spray head are not replenished by new fuel when the injection is stopped and then restarted. Also increasing injection pressure in post injection will reduce the Soot emission dramatically while NO is in control and it is due to increasing fuel burning rate in post injection pulse.


2014 ◽  
Vol 62 (2) ◽  
pp. 303-312 ◽  
Author(s):  
Xiaobei Cheng ◽  
Liang Chen ◽  
Guang Hong ◽  
Fangqin Yan ◽  
Shijun Dong

Fuel ◽  
2019 ◽  
Vol 258 ◽  
pp. 116131 ◽  
Author(s):  
Yan Wu ◽  
Pan Wang ◽  
Sheikh Muhammad Farhan ◽  
Jing Yi ◽  
Lili Lei

The article takes a gander at inevitable results of logical leisure with whirl enhancing modifications on a right away Injection diesel engine. 4 holes at a diversion over every chamber with estimations of the outlet start from 2, 2.five, 3 and 3.5 mm are through within the chamber with affordable tendency concerning the chamber center factor Numerical guesses are the first-class change to provide clean enduring of the fluid circulate wonder in a DI Diesel Engine. outcomes discover that the unessential beginning of two.five mm (2nd) bypass on an unequalled begin and excessive weight. Spin development just motor vitality massiveness increment with the changing starting widths. The chamber with 2.five mm establishing make a most vital execution improvement while the chambers with excessive broadness than second hole bypass on a to a few diploma chop down execution. whilst the development in partition transversely over develops the move discipline characteristics like spin, the execution decays beyond 2.five mm. considering the execution attitude an ensuing hole gives improved ingesting and finally most outrageous load for the proportional gas implanted. alternate ultimate holes have to a few diploma more fiery debris launch. in view that numerical results exhibited that ensuing hole offers a transcendent. Of all of the splendid numerical modifications the resultant chamber gives stepped forward presentation and lessens the fee and dreary experimentation tests.


Author(s):  
Theodoros C. Zannis ◽  
Dimitrios T. Hountalas ◽  
Elias A. Yfantis ◽  
Roussos G. Papagiannakis

A multi-zone combustion model is used in the present study to examine the effect of increased in-cylinder oxygen availability (either by using oxygenated fuels or by increasing the oxygen percentage of intake air) on direct injection (DI) diesel engine performance characteristics and pollutant emissions. Simulations are produced for a single-cylinder DI diesel engine (“Lister LV1”) by keeping constant the oxygen content of in-cylinder fuel/air mixture and the engine brake torque. The effects of the two oxygen-enhancement techniques on combustion characteristics, soot and NO concentrations inside the combustion chamber are examined using model predictions for a common diesel oil, a neat oxygenate and the case of increasing the oxygen fraction of intake air. The multi-zone model is also utilized to interpret the relative impact of fuel-side and air-side oxygen on soot formation mechanism by examining the temporal evolution of combustion characteristics and soot formation and oxidation rates inside the fuel jet zones. Evaluation of the theoretical results revealed that the increase of in-cylinder oxygen availability by both techniques resulted in earlier initiation of combustion, increase of peak cylinder pressure and increase of in-cylinder and exhaust NO concentrations. It resulted also in reduction of exhaust gas temperature and exhaust soot values. Fuel oxygen addition was proven to be more influential on combustion process and consequently, on soot and NO formation mechanism compared to oxygen-enhancement of intake air. This is attributed to the higher oxygen availability inside each fuel jet zone, which is observed in the case of oxygenated fuel combustion.


Author(s):  
Arjan Helmantel ◽  
Joop Somhorst ◽  
Ingemar Denbratt

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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