scholarly journals Nanostructure changes in diesel soot during NO2–O2 oxidation under diesel particulate filter-like conditions toward filter regeneration

2018 ◽  
Vol 20 (8-9) ◽  
pp. 953-966 ◽  
Author(s):  
Madhu Singh ◽  
Mek Srilomsak ◽  
Yujun Wang ◽  
Katsunori Hanamura ◽  
Randy Vander Wal
Keyword(s):  
Diesel Particulate Filter ◽  
Surface Oxidation ◽  
Soot Oxidation ◽  
Diesel Soot ◽  
Particulate Filter ◽  
Exhaust Gas ◽  
Fringe Analysis ◽  
Diesel Particulate ◽  
Oxidation Rates ◽  
Passive Regeneration

Development of the regeneration process on diesel particulate filters requires a better understanding of soot oxidation phenomena, especially its relation to soot nanostructure. Nitrogen dioxide (NO2) is known to play an essential role in passive regeneration by oxidizing soot at low temperatures, especially in the presence of oxygen (O2) in the exhaust. However, change in soot nanostructure due to oxidation by NO2–O2 mixtures has not received much attention. This work focuses on nanostructure evolution during passive regeneration of the diesel particulate filter by oxidation of soot at normal exhaust gas temperatures (300°C–400°C). High-resolution transmission electron microscopy of partially oxidized model carbons (R250, M1300, arc-generated soot) and diesel soot under NO2–O2 mixtures is used to investigate physical changes in nanostructure correlating with the material’s behavior during oxidation. Microscopy reveals the changing nanostructure of model carbons during oxidation while fringe analysis of the images points to the differences in the structural metrics of fringe length and tortuosity of the resultant structures. The variation in oxidation rates highlights the inter-dependence of the material’s reactivity with its structure. NO2 preferentially oxidizes edge-site carbon, promotes surface oxidation by altering the particle’s burning mode with increased overall reactivity of NO2+O2 resulting in inhibition of internal burning, typically observed by O2 at exhaust gas temperatures.

A Novel α-Al2O3 Diesel Particulate Filter with Alkali Metal-Based Catalyst for Diesel Soot Oxidation

2013 ◽  
Vol 56 (1-8) ◽  
pp. 473-476 ◽  
Author(s):  
Keisuke Mizutani ◽  
Kensuke Takizawa ◽  
Hironobu Shimokawa ◽  
Takumi Suzawa ◽  
Naohisa Ohyama
Keyword(s):  
Alkali Metal ◽  
Diesel Particulate Filter ◽  
Soot Oxidation ◽  
Diesel Soot ◽  
Particulate Filter ◽  
Diesel Particulate ◽  
Diesel Soot Oxidation ◽  
Α Al2o3

Experimental Analysis of Sudden Pressure Increase Phenomenon by Real-Time Internal Observation of Diesel Particulate Filter

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Rui Fukui ◽  
Yuki Okamoto ◽  
Masayuki Nakao
Keyword(s):  
Particulate Matter ◽  
Pressure Drop ◽  
Diesel Particulate Filter ◽  
Operating Conditions ◽  
Particulate Filter ◽  
Exhaust Gas ◽  
Visualization Method ◽  
Diesel Particulate ◽  
Wide Perspective ◽  
Deposit Layer

As a way of reducing the amount of particulate matter (PM) contained in the exhaust gas, diesel particulate filter (DPF) is widely used. To keep the condition of DPF normal and effective, estimation of the amount of PM deposits in the DPF is important. The estimation is mainly conducted based on the value of pressure drop across the DPF. Occasionally, the value of the pressure drop rises suddenly and it leads to overestimation of the amount of PM deposits. In order to elucidate the cause of the sudden pressure drop increase phenomenon, this paper first reveals the engine operating conditions which invoke this phenomenon. The authors also have developed a visualization method to realize the wide-perspective internal observation of the DPF. The observation experiment has been conducted with a commercial engine and DPF under the revealed conditions. Experimental results make clear that the phenomenon is caused by PM deposit layer collapse and channel plugging.

Cylinder Pressure Information-Based Postinjection Timing Control for Aftertreatment System Regeneration in a Diesel Engine—Part II: Active Diesel Particulate Filter Regeneration

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Hyunjun Lee ◽  
Jaesik Shin ◽  
Manbae Han ◽  
Myoungho Sunwoo
Keyword(s):  
Diesel Particulate Filter ◽  
Fuel Injection ◽  
Control Method ◽  
Particulate Filter ◽  
Exhaust Gas ◽  
Cylinder Pressure ◽  
Gas Temperature ◽  
Diesel Particulate ◽  
Dpf Regeneration ◽  
Exhaust Gas Temperature

The successful utilization of a diesel particulate filter (DPF) to reduce particulate matter (PM) in a passenger car diesel engine necessitates a periodic regeneration of the DPF catalyst without deterioration of the drivability and emission control performance. For successful active DPF regeneration, the exhaust gas temperature should be over 500 °C to oxidize the soot loaded in the DPF. Previous research increased the exhaust gas temperature by applying early and late post fuel injection with a look-up table (LUT) based feedforward control implemented into the engine management system (EMS). However, this method requires enormous calibration work to find the optimal timing and quantity of the main, early, and late post fuel injection with less certainty of accurate torque control. To address this issue, we propose a cylinder pressure based multiple fuel injection (MFI) control method for active DPF regeneration. The feedback control of the indicated mean effective pressure (IMEP), lambda, and DPF upstream temperature was applied to precisely control the injection quantity of the main, early, and late post fuel injection. To determine their fuel injection timings, a mass fraction burned 60% after location of the rate of heat release maximum (MFB60aLoROHRmax) was proposed based on the cylinder pressure information. The proposed control method was implemented in an in-house EMS and validated at several engine operating conditions. During the regeneration period, the exhaust gas temperature tracked the desired temperature, and the engine torque fluctuation was minimized with minimal PM and NOx emissions.

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