-focusing on effects of sulfur on latest aftertreatment devices-

Transcription

1 Further Challenge in Automobile and Fuel Technologies for better air quality 4th JCAP Conference Diesel WG Report -focusing on effects of sulfur on latest aftertreatment devices- June 1, 2005

2 Research Objectives 2 Objectives To study effects of fuel quality (sulfur, etc.) on exhaust emissions reduction performance of NOx catalyst and on CO2 emissions, to clarify the direction of future technologies for diesel vehicles and their fuel. Technologies to be evaluated NOx catalyst technologies (with DPF) Urea-SCR system NOx storage reduction catalyst NSR) system Fuel quality sulfur: 0 to 50 ppm Aromatics series and T90

3 Scenario for emissions reduction Example of heavy duty vehicles 3 PM g/kwh New short-term regulations NOx Catalyst +DPF DPF High-pressure injection/ Supercharger Current status Limitations of exhaust emissions reduction without aftertreatment New long term Post new long term NOx g/kwh Urea-SCR system NOx catalyst technologies are important for future.

4 NO catalyst technology (1) Urea-SCR 4 Urea hydrolysis SCR Selective Catalytic Reduction (NH 2 ) 2 CO + H 2 O 2 NH 3 + CO 2 Urea NOx reduction by NH 3 4 NH NO + O 2 4 N H 2 O 8 NH NO 7 N H 2 O The reaction below is active at low temperature. 2NH 3 +NO+NO 2 2N 2 +3H 2 O Effective NO/NOx ratio at around 0.5)

5 Exhaust GasTemperature of HD Engine 5 Temperature at SCR catalyst inlet Average exhaust gas temperature 254 Average exhaust gas temperature 211 Time s Exhaust gas temperature is low in JE05 mode which simulates urban driving. To improve activity of NOx catalyst at low temperature is important.

6 Example of Engine with Urea-SCR System 6 Low temp. activity is improved by increasing NO 2 /NOx ratio to be around 50%, by installing Oxi. cat. before SCR cat..

7 NOx Catalyst Technologies (2)NSR NSR:NOx storage reduction Storage of NOx (sulfur poisoning occur) ( lean air fuel ratio) Reduction of stored NOx ( fuel rich ) 7 Repetition Periodic desulfurization (high temp.) is required to recover from poisoning. Deteriorate both fuel economy and catalyst durability. Frequency of desulfurization can be decreased by reducing sulfur in fuel. Improve both fuel economy and NOx emission Periodic desulfurization ( fuel rich/ high temp. )

8 Example of engine with NSR DPF+NSR 8 PM-NOx simultaneous reduction catalyst system EGR Valve Common Rail Injection System Throttle Valve EGR Cooler Pre -EGR Catalyst Inter -Cooler PM-NOx Simultaneous reduction catalyst Intake Air Exhaust Gas Fuel Injector

9 Outline of Study Effect of sulfur Urea-SCR To study sulfur effect on reduction performance at low temperature operation NOx storage reduction catalyst NSR) 9 To study sulfur effect on fuel economy and reduction performance during mileage accumulation test (desulfurization control modified in accordance with fuel sulfur level) Effect of other fuel properties To study Influence of aromatics and distillation characteristics on emission reduction performance (Fuel Matrix Test)

10 Schedule 10 Items to be evaluated FY Supplement Urea- SCR Sulfur (red. performance at low temperature) Other properties Sulfur (mileage accumu.) NOx Catalyst NSR Influence on fuel economy Change in exhaust gas (NOx) Other properties Aromatic series/t90 New type combustion fuel effect Biofuel (FAME) Single cylinder test (outsourced) (

11 11 Evaluation of NOx reduction Performance of Urea-SCR System at Low Temperature Engine Operation

12 Urea-SCR: Objectives 12 To evaluate the difference in NO 2 /NOx ratio as well as NOx reduction performance with/without oxidation catalyst before Urea- SCR system at low temperature Aiming to check the influence of sulfur poisoning of oxidation catalyst on NOx Engine Engine speed/load Oxidation catalyst NO NO 2 Test parameters Urea-SCR Urea-SCR Equivalent ratio of urea/ammonia 4NO+4NH 3 +O 2 4N 2 +6H 2 O Active at low temperature NO 2 +NO+2NH 3 2N 2 +3H 2 O

13 Urea-SCR: Test Conditions 13 Test Engine Engine B Engine for heavy duty trucks (Complying with longterm regulations) Test Fuel + Urea-SCR system S10ppm diesel fuel J2D01 Test to be conducted Specifications of Engine B To compare NO 2 /NOx ratio with and without oxidation catalyst To check influence of oxidation catalyst on NOx reduction rate

14 Comparison of NO 2 /NOx ratio with and w/o Oxi. Cat. 14 Brake torque of engine With oxidation catalyst or less Brake torque of engine Without oxidation catalyst NO 2 /NOx ratio increases at low temperature due to installation of oxidation catalyst.

15 15 Comparison of NOx reduction with and w/o Oxi. Cat. Improvement in NOx reduction rate at low temperature (around 200 ) by installation of oxidation catalyst. NO reduction rate SV=8000 Average temperature of catalyst NO2/NOx ratio reduction rate (with oxidation catalyst) reduction rate (without oxidation catalyst) NO2/NO ratio with oxidation catalyst) NO2/NO ratio without oxidation catalyst)

16 16 Mileage Accumulation Test to Study Influence of sulfur on NSR catalyst

17 NSR Test Outline 17 Long distance mileage accumulation tests using vehicle/engine equipped with NSR (including DPF+NSR system) Test fuel: Three types of diesel fuel with different sulfur. (0, 10, and 50ppm) Desulfurization control is modified according to the sulfur of the test fuel during mileage accumulation (less frequent control for lower sulfur) Measurement items Fuel economy Exhaust emission during mileage accumulation

18 NSR Mileage accumulation test conditions 18 Test vehicle/engine and test conditions 2 types of engine 2 types of vehicle NO Name of vehicle/engine Engine Aftertreatment displacement L System Driving distance km Driving mode Measurement mode Engine A 3.8 NSR 10,000 11lap D13/ED12 Engine D 4.0 DPF+NSR 50,000 D13/JE05 Vehicle B 2.0 DPF+NSR 30, lap 3.0 DPF+NSR 80, lap CD34 (hot&cold) CD34 (hot&cold) Test fuel Test fuel 3 types of fuel with different sulfur: 0, 10, and 50ppm

19 NSR Effect of fuel sulfur on fuel economy 19 Driving Mode km Economy for S0 Economy for S10 Economy for S50 Engine A 10, Engine D 50, Vehicle B 11 lap 30,000 Planned for Another vehicle ( 11 lap 80, (outsourced) 5.98 (interim) Planned for FY 2005 (15000 km intermediate value Fuel economy benefit by sulfur reduction ( 50ppm to 10ppm) NO Vehicle/engine Driving mode Driving distance km Fuel economy improvement (From S50 to S10) Engine A 10,000 Engine D 50,000 (interim value) Vehicle B 11 lap 30,000

20 NSR Effect of fuel sulfur on NOx reduction Engine D(DPF+NSR) S0ppm/D13 S10ppm/D13 S50ppm/D13 S0ppm/JE05 S10ppm/JE05 S50ppm/JE NOx reduction rate Driving distance km The deterioration in NOx reduction rate can be restrained as the sulfur is reduced. The difference in Nox reduction rate between D13 and JE05 mode is assumed to result from the difference in exhaust gas temperature.

21 Comparison of exhaust gas temperature 21 Exhaust gas temperature D13: Average exhaust gas temperature 293 JE05: Average exhaust gas temperature 197 Time s Average exhaust gas temperature for JE05 mode is lower than that for D13 mode by about 100.

22 NSR Effect of fuel sulfur on NOx reduction Vehicle B (DPF+NSR) 22 NOx reduction rate Driving distance km Reference 10 15: Avg. exhaust gas temperature 345 CD34: Avg. exhaust gas temperature 325 The deterioration in NOx reduction rate can be restrained as the sulfur is reduced.

23 23 Matrix Test for Evaluating Influence of Fuel Properties Other than sulfur on NSR catalyst

24 Matrix test result Engine A (NSR) NOx emissions and NOx reduction rate before and after catalyst While NOx emissions measured after an engine tends to increase as fuel gets lighter, exhaust emissions level is slightly lower for lighter fuel because aftertreatment NOx reduction rate is improved. 24

25 Summary 25 Influence of sulfur on NSR (ongoing) Effect of reduction of sulfur on fuel economy improvement has been quantified. Effect on exhaust gas has been proved that the deterioration of NOx reduction rate is restrained as the sulfur is reduced. Evaluation of Urea-SCR system (ongoing) The study has proved that the installation of oxidation catalyst before Urea-SCR is effective to improve NOx reduction performance at low temperature. It has also suggested the possibility that the reduction of sulfur in fuel has some effect on maintaining the performance of the oxidation catalyst.

26 Future plan Study on the effect of fuel quality for new combustion 26 NOx emission reduction mainly by NOx after-treatment devices (Exh. Temp. high enough for after-treatment activity.) NOx emission reduction mainly by new-type combustion (Low-temperature premixed type combustion) Because of the low exhaust gas temperature aftertreatment device hardly works. Reference: report by Isuzu Research Center JCAP plans to study the fuel effects (T90, aromatic series volume, cetane rating, etc.) for new-type combustion using single cylinder engine in FY2005.

27 Reference 27

28 Engine/Vehicle Specifications 28 Engine A Engine B Engine D Emission Control NSR Cat.+DPF Type Small Truck Engine Type In-line 4 F.I.E. Common-Rail EGR Cooled EGR Vehicle B Emission Control NSR Cat. + CRDPF Type Passenger Engine Type In-line 4 (TCI) Displacement 2.0L F.I.E. Common-Rail EGR Cooled EGR High-tech vehicle (outsourced) Emission Control Type Engine Type Displacement F.I.E. EGR Oxi. Cat.+DPF de-nox Cat. Passenger In-line 4(TCI) 3L Common-Rail Cooled EGR

29 Fuel for mileage accumulation Test Three types of fuel with different sulfur 0, 10 and 50ppm J2D25 J2D01 J2D02 J2D11 S0 S10 S50 S0 S0 Density g/cm IBP ( ) 10 vol% vol% vol% EP mm (vol ) HPLC vol% mass ppm < <1 <1 Elemental analysis mass% Hydrogen content mass% Net heating value J/g HFRR Remarks S10 S50 Note) Either of above S0 fuels has different properties from S10 and S50 fuels, because they use different base materials from those used for conventional diesel fuel. 29

30 Fuel for Matrix Test 30 J2D01 J2D03 J2D04 J2D05 J2D06 Density g/cm Distillation Property ( ) IBP vol% vol% vol% EP Kinetic viscosity mm (vol ) Elemental Analysis vol% mass ppm mass% mass% J/g HFRR Remarks Base

31 Result for Engine D (DPF+NSR) 31 Result of exhaust emissions Driving distance km S10ppm Fuel S0ppm Fuel S50/S50 Control Mode Item NOx PM HC CO NOx PM HC CO NOx PM HC CO JE05 D13 JE05 D13 JE05 D13 JE05 D13 (g/kwh) (g/kwh) (g/kwh) (g/kwh) (g/kwh) (g/kwh) (g/kwh) (g/kwh) NMHC NMHC NMHC 3.5t GVW (g kwh) Result of fuel economy obtained by mileage accumulation test S10ppm S0ppm S50ppm Fuel economy for modified 11 lap km/l (Average of all driving data) *5.98(interim *Intermediate report value for 15000km Improvement in fuel economy due to sulfur reduction (S10 S0): 1.1% Improvement in fuel economy due to sulfur reduction (S50 S10): 4.7% (interim)

32 Driving distance km Result for Vehicle B (DPF+NSR) Result of exhaust emissions S10ppm Fuel NOx PM HC CO (g/km) CD34 (g/km) Hot CD34 (g/km) Cold (g/km) CD34 (g/km) Hot CD34 (g/km) Cold (g/km) CD34 (g/km) Hot CD34 (g/km) Cold (g/km) NMHC Result of fuel economy obtained by mileage accumulation test Fuel economy for modified 11 lap km/l (Average of all driving data) Driving distance km S50ppm Fuel Item NOx PM HC CO (g/km) CD34 (g/km) Hot CD34 (g/km) Cold (g/km) CD34 (g/km) Hot CD34 (g/km) Cold (g/km) CD34 (g/km) Hot CD34 (g/km) Cold (g/km) CD34 (g/km) Hot CD34 (g/km) Cold NMHC ( ) (g/km) 0.17 Improvement in fuel economy due to sulfur reduction (S50 S10): 5.2%