This content is not included in your SAE MOBILUS subscription, or you are not logged in.
A Comprehensive Study of Diesel Combustion and Emissions with Post-injection
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 16, 2007 by SAE International in United States
Annotation ability available
A comprehensive study is carried out in order to better understand combustion behavior in a direct injection Diesel engine working under multiple injection strategies, in particular when using post-injections. The aim of the study is to provide criteria to more easily define optimized injection strategies.
During the study two main phenomena have been observed and characterized: an acceleration of the final stage of combustion and an apparent disconnection between the combustions of the two pulses (“split flame”). Thanks to the combustion acceleration phenomenon, if the post-injection is placed near enough the main injection, the end of combustion can take place even earlier compared to the case with a single main injection. In such conditions NOx emissions increase (most likely due to a higher temperature level during the last stage of combustion), but soot and specific fuel consumption decrease (due to a faster last phase of combustion).
The second observed phenomenon is that if the post-injection is not excessively near to the main injection, the two combustions act as two independent combustions (“split flame”), thus allowing an easier interpretation of the main behaviors of the whole combustion process. As an example, the two observed phenomena help to understand why a small post-injection is an effective way to reduce soot emission with no fuel penalty.
The knowledge gained during the study is used to propose some improvements of the combustion process under certain operating conditions.
CitationDesantes, J., Arrègle, J., López, J., and García, A., "A Comprehensive Study of Diesel Combustion and Emissions with Post-injection," SAE Technical Paper 2007-01-0915, 2007, https://doi.org/10.4271/2007-01-0915.
- Anrigo P. “Evolution of the Diesel Engines; From the Kaizen to the Innovate Concepts, the Various Roads to Environment-friendly Progress” 4 th conference on Thermo- and fluid dynamic processes in Diesel engines 2006 Valencia (Spain) 13-15th September 2006
- Guerrassi N. Dupraz P. “A Common Rail Injection System for High Speed Direct Injection Diesel Engines” SAE Paper 980803 1998
- Benajes J. Molina S. García J.M. “Influence of Pre- and Post-injection on the Performance and Pollutant Emissions in a HD Diesel Engine” SAE Paper 2001-01-0526 2001
- Chen S.K. “Simultaneous Reduction of NOx and Particulate Emissions by Using Multiple Injections in a Small Diesel Engine” SAE Paper 2000-01-3084 2000
- Hotta Y. Inayoshi M. Nakakita K. Fujiwara K. Sakata I. “Achieving Lower Exhaust Emissions and Better Performance in a HSDI Diesel Engine with Multiple Injection” SAE Paper 2005-01-0928 2005
- Han Z. Uludogan AN. Hampson G.J. Reitz R.D. “Mechanism of Soot and NOx Emission Reduction Using Multiple-injection in a Diesel Engine” SAE Paper 960633
- Lapuerta M. Armas O. Hernández J.J. “Diagnostic of DI Diesel Combustion from In-cylinder Pressure Signal by Estimation of Mean Thermodynamic Properties of the Gas” Applied Thermal Engineering 19 5 513 519 1999
- Bosch W. “The Fuel Rate Indicator: a New Measuring Instrument for Display of the Characteristics of Individual Injection” SAE Paper 660749 1966
- Desantes J.M. Arrègle J. Fenollosa C. Salvador F.J. “Analysis of the Influence of Injection Rate and Running Conditions on the Heat Release Rate in a DI Diesel Engine” SAE Paper 2001-01-3185 2001
- Arrègle J. López J.J. García J.M. Fenollosa C. “Development of a Zero Dimensional Diesel Combustion Model. Part 1: Analysis of the Quasi-steady Diffusion Combustion Phase” Applied Thermal Engineering 23 1301 1317
- Dec J.E. “A Conceptual Model of DI Diesel Combustion Based on Laser-sheet Imaging” SAE Paper 970873 1997