Fuel Properties and Vehicle Emissions AVECC 24 at Beijing, April 26-28, 28, 24 Yasunori TAKEI Fuel & Lubricant committee Japan Automobile Manufacturers Association Automobiles and the Environment Global Environment Urban Environment CO2 Emissions VOC,NOx,PM Alternative Fuels Energy Security Convenience Recycle Economy Safety
Relation between Gasoline Properties and Vehicle Performance Properties Vehicle Performance Octane Number RVP / T1 T5 T9 FBP Sulfur Aromatics Olefins Di-Olefins Unwashed Gum Washed Gum Detergent Knocking Catalyst poisoning deposit Oxidized fuels Power/Acceleration Fuel economy Startability Driveability Evaporative emission Exhaust emission Material compatibility Alcohol Metals Engine oil degradation Spark plug fouling Engine Reliability Fuel Requirement from Automobile Automobile associations in US, Europe and Japan have developed world wide recommendations for Quality fuels called World Wide Fuel Charter (WWFC). strongly recommends WWFC, at least, comply with regulation. Category 1: Markets with no or first level of emission control Category 4: Category 4: Markets with further advanced requirements for emission control, to enable sophisticated NOx and particulate matter after-treatment technologies. Category 3: Markets with advanced requirements for emission control or other market demands. Category 2: Markets with stringent requirements for emission control or other market demands.
Summary of Existing Data Analysis Vehicle:3WAY Catalyst + Feedback :Decreasing, :Increasing, ~:No tendency :Different tendency at each study Fuel Properties :when fuel properties decreasing RVP No oxygenates blend ~ ~ ~ ~ ~ ~ Oxygenates blend ~ ~ ~ ~ ~ ~ ~ Dist. T5 Aromatics 2~35v% ~ ~ ~ ~ ~ T9 Olefins 5~25v% ~ ~ Compositions Olefins Aromatics ~ Other properties is constant ~ ~ ~ ~ Benzene ~ ~ Sulfur ditto ~ ~ ~ MTBE ditto ~ ~ Detergent ditto JCAP Conference, 3th Sept. 1998 Tailpipe Emissions HC CO NOx Benzene 1,3-Butadien Formalfehyde Acetoarehyde Note: Blank is no data Trend of Emission Regulation in Japan CO HC NOx 1 5 1 5 6% 5% 45% 75% 59% 48% 5% 8% Change test cycle (1 mode 1 15 mode) Change test cycle (1 mode 1 15 mode) 98-99% reduction 1.6% 2.6%.8% 1.3% 1 Change test cycle (1 mode 1 15 mode) 5 27% 8% 2.6% 1.6% 1965 197 1975 198 1985 199 1995 2 25
Technology Trend for Low Emission Key is to maximize the catalyst performance. 1. Minute air fuel ratio (A/F) control - Intelligent A/F management (high performance ECU etc.) - improving atomization of injected fuel (multi hole injector etc.) - Feedback systems (A/F sensor, 2O 2 sensors system etc.) 2. Quick warm-up of catalyst - Small size warm-up catalyst - Insulated exhaust manifold - Sophisticated engine control (Ignition timing, A/F control etc.) Improving catalyst performance itself - High cell density catalyst - High loading of precious metals Example of LEV System Wide range air-fuel sensor Small volume warm-up catalytic converter Stainless steel long-necked exhaust S/C Low temperature volume exhaust pipe (double) Joint Fuel system Improve atomization of injected fuel Improve ports (reduce wetness) Reduce injection fuel density Control Optimum catalytic conversion efficiency Catalytic converter temperature Catalyst deterioration Independent injection O 2 Sensor U/F Thin U/F catalytic converter
Relationship between Catalyst Efficiency and Inlet Gas Temperature better 1 HC worse Conversion Rate, % 8 6 4 2 Fuel sulfur : 3ppmw 1 2 3 4 5 Inlet Gas Temperature, deg.c Cumulative HC Emissions on LA#4 Mode Aged Catalyst Cumulative HC Emission (%) 1 75 5 25 1.3 litter Close-Coupled Catalyst System LA#4 Mode SAE96797
Effect of Small Volume Warm up Catalyst System A Warm-up.7 liter System B 1.3 liter Bed Temperature (deg.c) 6 4 2 Main Warm-up 1.1 liter.5 liter Main 4 8 12 16 Time (sec) SAE96797 Effect of Warm-up Catalyst Volume on HC and NOx Emissions System A Warm-up.7 liter System B 1.3 liter Normalized Emission 2. 1.5 1..5 HC Main 1.1 liter A B System Normalized Emission 2. 1.5 1..5 NOx A B System.5 liter SAE96797
Conversion Characteristic of the 3 Way Catalyst better 1 window Conversion ratio (%) 8 6 4 2 HC CO NOx worse 12 13 14 15 16 17 A/F Minute Air Fuel Ratio Control 2-O 2 Sensors System A/F Main Feedback Front O2 Sensor Precise Air-Fuel Ratio Control ECU A/F Sub-Feedback Fuel Injector Catalytic Converter Rear O2 Sensor %1 Conversion Rate % 1 5 NOx HC CO Image of A/F Control Window Stoichiometric 1-O2 Sensor System 2-O2 Sensor System Rich Air-Fuel Ratio Lean OEM Homepage
Comparison of Air/Fuel Management between Current and ULEV Technology Target ±.2 A/F Current 48.9% Honda ULEV 84.9%.94 1. 1.6 AIR-EXCESS FACTOR λ Honda 97 sulfur data symposium of CRC Auto/Oil Symposium, Sept. 97 Effects of increasing Cell Density of Catalyst on Emission Reduction Cold Bag NMHC, g/mile.3.2.1 4mil 4cpsi *1) 2mil 6cpsi 2mil 8cpsi (current) Cell Density 2mil 9cpsi Catalyst Capacity :.9L Aging Condition : 5k-mile equivalent quick aged on engine dyno. 2 (or 4) mil is Thickness 1mil=25um Cell Density is Cell number per 1 inch 2 SAE 23-1-817(Re-arrange) *1) Estimation from the figure in the paper
Fuel Quality for Low Emissions Fuel quality to maximize the catalyst performance; For air fuel ratio control Distillation properties Detergent (preventing deposits) For quicker warm up of catalyst Lowering sulfur Metal Free For keeping higher conversion efficiency Lowering sulfur Metal Free Effects of Fuel Sulfur Content on Catalyst Efficiency better Conversion Rate, % 1 8 6 4 2 3ppmw 3ppmw SAE922179 worse 1 2 3 4 5 Inlet Gas Temperature, deg.c
Effects of Sulfur in Gasoline on Exhaust Emissions Relative THC 15 1 5 SULEV LEV1-LEV LEV1-LEV LEV2 ULEV SULEV LEV,ULEV Relative NOx 15 1 5 SULEV LEV1-LEV LEV1-LEV LEV2 ULEV SULEV LEV,ULEV -5 1 2 3 4 5 6 Sulfur (ppmw) -5 1 2 3 4 5 6 Sulfur (ppmw) SULEV : Super Ultra Low Emission Vehicle, ULEV : Ultra Low Emission Vehicle, LEV : Low Emission Vehicle SAE 2-1-219 Effects of Distillation Temperature on Exhaust Emissions Relative HC emissions (%) ULEV 6 ULEV LEV 4 LEV 2 base -2 6 7 8 9 1 11 12 13 5% Distillation Temperature (deg.c) Relative HC emissions (%) 6 ULEV LEV 4 2 base -2 13 14 15 16 17 18 9% Distillation Temperature (deg.c) ULEV : Ultra Low Emission Vehicle, LEV : Low Emission Vehicle SAE2-1-219 SAE 2-1-219 (Re-arranged)
OEM data Relative Exhaust Emissions Effects of IVD on Emissions 1 5 1 5 1 5 HC CO NOx 149 11 127 Rating '6' (dirty) Removal of IVD (*IVD=Intake Valve Deposit) 1 1 1 Rating '9-1' (Clean) Effects of Metal (Mn( Mn) ) on Ex. Emissions NMOG - g/mi CO - g/mi.12.1 Reference LDV 1K Std.8.6.4 Clear.2 MMT. 2 4 6 8 1 Miles 1.6 1.4 1.2 1..8.6.4.2. 2 4 6 8 1 Miles NOx - g/mi mpg.2.15.1.5. 25 24 23 22 21 2 4 6 8 1 Miles 2 2 4 6 8 1 Miles Alliance of Automobile Manufactures (22)
Experience in the Market (Manganese) OEM data Experience in the Market (Ferrocene) Red deposit is Oxides of Fe OEM Data
Experience in the Market (Ferrocene) Entrance Melting Exit Expansion OEM Data Fuel Issues to be discussed in China Properties Summary of Gasoline Market ( 2 Summer) Sulfur, ppmw 69 719 Cat.2 WWFC Cat.3 ~ 2 max 3 max RVP, kpa 32.3 ~ 67.3 55 ~ 7 T5, deg.c T9, deg.c 73.8 ~ 115.8 144.2 ~ 167.6 77 ~ 1 13 ~ 175 Aromatics, vol% 9.3 ~ 33.6 4. max 35. max Olefins, vol% Metals, ppm 18.3 ~ 38. Oxygen, wt%.1 ~ 34..1 ~ 13.9 vol% MTBE (Mn) 2. max 2.7 max (15 v% MTBE) N.D 1. max N.D
Conclusions 1. To achieve stringent emission regulations, minute air fuel ratio management, quick warm-up of catalyst after cold starting, and improvement of the catalyst are key technologies for automobiles. 2. In order that these technologies demonstrate their performance, lowering sulfur, adequate range of T5 and T9, detergent to keep intake systems clean and metal free will be very important. 3. As considering introduction plan of stringent emission regulation and current fuel quality in China, fuel regulation for these properties should be discussed. 謝謝 Thank you!