Active Regeneration Technology for DPF& NSR JASIC 9 th Plenary - - PowerPoint PPT Presentation

Active Regeneration Technology for DPF& NSR

JASIC

9th Plenary Meeting of WWH-OCE (11-12 January, 2005)

OCE Informal Document No. 25 Ninth Plenary Meeting of the Working Group On Off-Cycle Emissions 11&12 January 2005 Palais des Nations, Geneva

2

Needs for Active Regeneration

• Regeneration of accumulated soot on DPF is critical for

practical application.

• Exh. Temp. in urban driving is not enough for continuous

(passive) regeneration of CR-DPF or C-DPF.

• Therefore Japanese DPF installed engines in production

mostly apply active regeneration technologies. Those differ for each manufacturers’ design philosophy.

• An example already presented in SAE2004-01-0824 by

Japanese manufacturer.

• Active regeneration is also necessary for de-sulfurization of

NOx Storage Reduction (NSR) catalyst. Because sulfur in fuel is accumulated on NOx adsorbing material on the catalyst and poisons NOx reduction performance.

Passive Regeneration Operating Conditions

Engine Speed (rpm) Maximum Torque Engine Torque (Nm)

Passive Regeneration Region Urban Cycle with Full Payload Active Regeneration of a Particulate Filter is necessary

4

Technology Outline for DPF (SAE2004-01-0824)

• Accumulated soot amount on DPF is estimated by
• ECU. When the amount exceed the threshold,

active regeneration start to increase catalyst bed temp..

• In the active regeneration process, different

injection events (after inj. or post inj.) and different air management occur using electronic control of fuel inj. equipment, turbo-charger and EGR devices.

• The process continues several minutes, and

during the process, different level of exhaust gases are emitted from tail-pipe.

EGR Cooler Inter-Cooler Common Rail Injection System EGR Valve Air Flow Sensor VG Turbo Charger Exhaust Brake Pressure Sensor

• Temp. Sensor
• Temp. Sensor

Diesel Oxidation Catalyst Catalyzed Filter Intake Air Exhaust Gas

DPR-Cleaner

Diesel Engine System to Achieve PM Reduction

≥T ˚C ≥ β g/L ≥α g/L < β g/L <T ˚C <α g/L Exhaust Gas Temperature Accumulated Soot Amount Accumulated Soot Amount Post injection Normal Operation After Injection

Example of Regeneration Process of the DPR

Main Injection

After Injection Post Injection

Crank Angle

TDC BDC

Fuel Injection Quantity

Fuel Injection Pattern

Time Filter Bed Temp.˚C Target of Filter Bed Temp

.

Post Injection

Feedback

Fuel Injection Control

Filter Temperatures during Active Regeneration

(Under City Driving Condition with the Ave Speed of 24km/h)

Post Injection Filter Bed Temp(˚C) Vehicle Speed (km/h) 200 400 600 800 1000 20 40 60 80 100 100 200 300 400 500 Post Inj. After Inj.

Filter Rear Filter Front Filter Center

Time(sec)

10

Technology Outline for NSR

• Fuel rich circumstances for catalyst bed

necessary for NSR regeneration to remove sulfur.

• In the active regeneration process, much

sophisticated injection events (fuel injection to catalyst bed) and air management is necessary for fuel rich circumstances.

• The process continues several minutes, and

during the process, different level of exhaust gases are emitted from tail-pipe.

11

Intake Air Exhaust Gas Pressure Sensor Fuel Injector VG Turbo Charger Air Flow Sensor

• Temp. Sensor

Inter-Cooler Air-Fuel Ratio Sensor

• Temp. Sensor

Air-Fuel Ratio Sensor NSR Catalyst

DPNR Catalyst

Oxidation Catalyst

System Configuration for NSR+DPF System Configuration for NSR+DPF

EGR Valve EGR Cooler Throttle Valve Common Rail Injection System Catalyst Pre-EGR

12

Vehicle Speed 60km/h Const. 100sec. Bed Temp. (deg.C) Time 300 400 500 600 700

• Cat. Front
• Cat. Rear

Air Fuel Ratio 10 15 20 25 35 30 Low temp.combustion & EPI SOx, H2S (ppm) 200 400 600

H2S SO2

800 Rich and lean

An Example of Active Regeneration (De- Sulfurization) for NSR Catalyst

13

Summary

• Active regeneration is necessary for both

DPF and NSR technology.

• The regeneration process continues

several minutes, and in the process different emission characteristics should be

• bserved. The duration and emission level

depend on design.

• We propose the different emission

characteristics during active regeneration should be considered in OCE-GTR.