Effect of Biodiesel Fuel on Emissions from Diesel Engine Complied with the Latest Emission Requirements in Japan Ref: JSAE Paper No.

Transcription

1 Biodiesel Technical Workshop Effect of Biodiesel Fuel on Emissions from Diesel Engine Complied with the Latest Emission Requirements in Japan Ref: JSAE Paper No November 5-6, Kansas City, MO Tom KAKIHARA Japan Automobile Manufactures Association Fuels and Lubricants Committee

2 Contents Objectives Test Engine / Test Cycles Test Fuel Properties Results Summary 2/16

3 Objectives In general characteristics of FAME, LHV in FAME is lower than conventional diesel fuel. Concerning about operation in Urea SCR system with FAME blended diesel fuel. To investigate the impact of high FAME blends (>B5) on exhaust emissions, fuel consumption and SCR catalyst performance. To investigate the causes of the SCR performance degradation with high FAME blends. A MD diesel engine complied with the latest emission requirements in Japan (JP2009) was utilized 3/16

4 Test Engine / Test Contents Test Engine: *Post New Long-Term std : Similar to US10 std - L6-7.5L for MD Truck with C/R, DOC/DPF/SCR/DOC - Comply with PNLT* (JP2009) Test Contents: DPF SCR <Engine Test> **Tokyo Metropolitan Government cycle - Transient (JP Emission Cert. Test Cycle) - TMG** #5, #8, and #10 Transient - Steady State (11 conditions) <Analysis Test> - CVCV*** Combustion Observation Ave. Speed in KPH -: TMG #5: TMG #8: TMG #10: 44.4 ***Constant Volume Combustion Vessel 4/16

5 Test Fuel Property Test fuel Diesel () Biodiesel () 15 C Kinematic 30 C Cetane number g/cm mm 2 /s g/cm mm 2 /s 55.5 Carbon content 86.1 mass% 84.0 mass% Hydrogen content 13.8 mass% 13.6 mass% Oxygen content <0.1 mass% 2.3 mass% Sulfur content 4 massppm 3 massppm Lower heating value 42,940 J/g 41,850 J/g Distillation IBP C T C T C T C EP C 35,584 J/cm 3 35,041 J/cm C C C C C B100 (PME) g/cm mm 2 /s mass% 12.4 mass% 11.2 mass% 1 massppm 37,050 J/g 32,422 J/cm C C C C C 5/16

6 Eng-out Soot [-] Eng-out NOx [-] Results Eng. Out Emissions & BSFC BSFC [-] Eng-out CO [-] Eng-out THC [-] BSEC [-] F/F: Warm up with rated speed, 80kph: Warm up with 80kph road load Relative Comparison / / / (F/F) no data (F/F) (80kph) (80kph) TK5 TK8 TK / 0.77 TK5 TK8 TK (F/F) 0.86 (80kph) Slight increase in engine-out NOx and BSFC with. - Significant reduction in engine-out CO and Soot with TK5 TK8 TK (F/F) (80kph) / TK5 TK8 TK (F/F) (F/F) 0.97 (80kph) (80kph) TK5 TK8 TK10 / TK5 TK8 TK10 6/16

7 Results Tailpipe Emissions & NOx Conv. N 2 O [g/kwh] NOx [g/kwh] NH 3 [g/kwh] NOx reduction [pt] / =1.06 (F/F) (F/F) 1.20 (80kph) (80kph) TK5 TK8 TK10 TK5 TK8 TK (F/F) -0.5 (F/F) (80kph) TK5 TK8 TK (80kph) TK5 TK8 TK10 - Significant increase in tailpipe NOx (6 to 43%) with (even though slight increase in engine-out NOx) due to fall in NOx conversion performance of SCR. 7/16

8 Assumption of Changes in Tailpipe NOx Eng-out NO 2 /NOx [%] SCR-in NO 2 /NOx [%] no data (F/F) (80kph) TK5 TK8 TK (F/F) (80kph) TK5 TK8 TK10 Reference Ref: Mizushima N. et al., SAE , "Effect of Biodiesel on NOx Reduction Performance of Urea-SCR system" - Decrease in the SCR inlet NO 2 /NOx ratio as well as engine-out NO 2 /NOx ratio with. - Mizushima et al. reported that NOx reduction efficiency in SCR was affected by amount of FAME and the factor was changes in SCR-in NO 2 /NOx ratio by changes in amount of FAME contents. 8/16

9 Traces - Key Parameters for NOx Conversion (80kph) TK-8 10g 10g - NOx spike during the acceleration was observed because of in sufficient NO 2 with. 9/16

10 PN [#/kwh] Exhaust temp. [ C] Unregulated Tailpipe Emissions PAHs [ng/kwh] Aldehydes [mg/kwh] (F/F) DPF inlet (F/F) SCR inlet HCHO CH 3 CHO FAME content [mass %] FAME content [mass %] 1.E+10 9.E+09 (F/F) (F/F) 8.E E+09 6.E+09 5.E FAME content [mass %] Fluoranthene Pyrene FAME content [mass %] - Increase in unregulated emissions (aldehydes, PAHs and PN) and decrease in exhaust temperature by increasing amount of FAME accordingly. 10/16

11 Comparison in Engine Out NO2/NOx Ratio Increase in Eng.-out NO2/NOx ration by increasing in EGR rate. - Significant discrepancy in NO2/NOx ratio with, especially at high EGR rate condition. 11/16

12 Result - Heat Release Rate Heat Release Rate Heat Release Rate Ne=1250rpm, Q f =34mm 3 /st Ne=1250rpm, Q f =72mm 3 /st Light Load High Load Pilot Combustion Ignition Delay - Pilot combustion event is significant with /light load conditions due to higher cetane # and it made ignition delay in main injection shortened. - No difference in heat release rate with high load conditions. 12/16

13 Accum. HR [J] Results MFB (Mass Fraction of Burned fuel) * End of combustion (*MFB90) with was earlier than with because has lower LHV. *MFB90: 90% of Mass Fraction of Burned fuel 500 Ne=1250rpm, Q f =72mm 3 /st Crank angle [ CA atdc] 13/16

14 Flame Temperature by Two-Color Method NL: Natural Luminosity NL Temp NL Temp B100 NL Temp TASI [ms] Injection 75mm 3 w/: P inj =100MPa, t inj =1.058ms, X o2 =17%, T a =950K, r a =19.5kg/m 3 14/16

15 Flame temp. [K] Flame Temperature and KL Factor* KL B100 P inj =100MPa, X o2 =17% *KL Factor: A measure of soot particulate concentration B100 P inj =100MPa, X o2 =17% TASI [ms] TASI [ms] - When FAME content in fuel is increased, both flame temperature and KL are on a downward trend. a factor of decrease in - exhaust gas temp. - engine-out NO 2 /NOx ratio (in-cylinder NO oxidation rate) *KL Factor: A measure of soot particulate concentration. K is a measure of soot number density, units are #/cm3, and L is a measure of the path length along which the measurement is made, units cm. 15/16

16 Summary 1. Increase in tailpipe NOx with was observed due to the combination of increase in engine out NOx and decrease in NOx conversion ratio due to decrease in engine-out NO2/NOx ratio. 2. Cause of decrease in engine-out NO2/NOx ratio with is assumed that oxidation reaction of NO in combustion chamber is restricted due to lower flame temperature. 3. Decrease in exhaust temperature with was observed and unregulated components such as PN and aldehydes were increased. 4. Factors of decrease in exhaust temperature with are earlier in the end of combustion and lower in flame temperature. - This issue can not be recognized by users/customers of vehicles, but stakeholders have to recognize there would be a negative impact to air quality. 16/16

17 End 17/16

18 Appendix 18/16

19 Test Engine / Test Cycle Engine type FIE Aspiration system Displacement Bore/Stroke Compression ratio Rated HP / Speed Max torque / Speed Emission regulation After Treatment System L-6 DI diesel, 4stroke cycle Common-rail system Turbocharger with intercooler 7,545 cm 3 (7.5L) f118 mm x 115 mm kw / 2500 rpm 785 Nm / 1100 ~2400rpm *Post new long-term (JP2009) pre-doc/dpf/scr/post-doc *Post New Long-Term std is similar to US10 std DPF SCR 19/16

20 Test Equipment / Instrument ENG Exhaust Emissions Engine-out Horiba MEXA-7100DEGR Horiba MEXA-1160CLT-H AVL 483 Micro soot sensor NOx, CO, THC, CO 2, NO (NO 2 /NOx ratio), Soot T Engine-out emissions SCR inlet Horiba MEXA-1160CLT-H NOx, NO (NO 2 /NOx ratio) SCR inlet NO 2 /NOx ratio T DPF T T SCR pre-doc T T Tailpipe emissions Tailpipe Iwata FAST-3100 (FTIR) N 2 O,NH 3 Full-Flow Dilution Tunnel Horiba MEXA-7200D Horiba MEXA-2000SPCS Impinger, High volume sampler NOx, CO, THC, CO 2, PN, Aldehydes, PAHs Exhaust Temperature T/C outlet pre-doc inlet DPF inlet DPF outlet SCR inlet Tailpipe 20/16

21 Test Cycle Transient Emission Te [Nm] Driving mode (Ave. speed = 27.3km/h) TMG-5 (Ave. speed = 18.0km/h) Vehicle specifications Conversion program Determine gear-shift positions Calculate engine speed and torque TMG-8 (Ave. speed = 28.6km/h) Engine operating mode TMG-10 (Ave. speed = 44.4km/h) Time 4 driving modes (, TMG-5, TMG-8, TMG-10) 2 pre-conditioning operations for mode (Rated Spd. & 80kph R/L) Vehicle spec. : T4 category T4 category T3 category Ne [rpm] 21/16

22 Test Cycle Steady State Emission Engine torque [Nm] (T4) Engine speed [rpm] Steady State Operating Point 22/16

23 Combustion Observation by *CVCV *CVCV : Constant Volume Combustion Vessel Timing control unit Combustion vessel Spark plug Injector Common rail system Amp Stirrer Pressure indicator Pressure transducer Vacuum pump Pressure indicator Mixer Mixed gas tank O 2 N 2 C 2 H 2 H 2 23/16

24 Engine Performance - Full-Load Torque Engine torque [Nm] B Engine speed [rpm] The use of leads to the slight decrease in max. torque. (Averaged value between 1000rpm and 2500rpm: B10-1.1%, -1.9%) 24/16

25 Ne [rpm] Q f /Q f_max [%] Accelerator [%] Trace in Engine Control Parameters Engine Control ( vs. ) Time after start of test cycle [s] There is no change in engine control between and, because has the almost same volumetric LHV as. 25/16