Effect of exhaust gas recirculation composition on soot in ECN spray A conditions

Abstract

Due to its strong impact on health, particulate matter is increasingly regulated by government emission standards for vehicles. As one of the sources of particulate matter is the soot produced by internal combustion engines, it remains a challenge to improve advanced combustion modes to reduce it. There is still, however, some lack of understanding about the formation and oxidation processes of soot, especially in “realistic” conditions, such as for example at high temperature and pressure conditions with or without the presence of exhaust gases. The objective of this study is to investigate soot formation in the case of n-Dodecane spray flames at conventional Diesel engine conditions generated in the New One Shot Engine by using diffused back-illumination extinction with different CO2 and water vapour contents. It was found that CO2 addition reduces the soot mass fraction if its volumetric concentration in ambient mixtures is at least 4.5% while 1% of water is sufficient to significantly reduce the soot mass fraction. The impact of the ambient mixture obtained in ECN spray A pre-burn vessels was also investigated to assess the accuracy against soot measurements available in the literature.

Large eddy simulation of transient combustion and soot recession in the ECN Spray A and D flames

“…The possible reason for this delay is likely due to the uncertainty of the EOI time reported in the experiment. Patel et al [48] carried out the soot measurement under the Spray A conditions in their new one shot engine (NOSE). The measured soot mass took approximately 0.8 ms AEOI to be fully oxidized, which agrees well with the complete soot oxidation time captured in the present simulated Spray A flame.…”

Characterization of the ECN spray A in different facilities. Part 2: spray vaporization and combustion

“…The initial and the boundary conditions are described in [29] and the main characteristics of the different facilities are summarized in Table 1. The NOSE and PPRIME_RCM facilities are more flexible to control the ambient gases composition [31] but due to the need of high compression ratio, the clearance volume is smaller than the one of the pre-burn vessel inducing more confinement. Each of the measurements presented in the following section has been repeated 5-10 times to provide statistical information.…”

Editorial: Main results from Engine Combustion Network – France project: characterization of new experimental facilities and study of Diesel evaporation and combustion processes using advanced optical diagnostics

“…This special issue presents results from this collaborative project with five new papers [3][4][5][6][7] covering all aspects of the work performed, from standardization issues to advanced optical diagnostic developments.…”

“…The three other papers are dedicated to the results obtained to provide new insights on the physical processes occurring during the atomization of the dense liquid spray [5], the combustion process [6] and soot formation [7] by implementing advanced measurement techniques.…”

“…In Patel et al [7] conducted unique experiments in order to study the effect of the presence of CO 2 and H 2 O in ambient gases on soot formation thanks to the flexibility of the experimental set-up in adjusting the initial composition of ambient gases. It was pointed out that both reduce soot mass fraction but with more H 2 O impact.…”