Automotive/Petroleum Industry Sulfur/Oxygen Test Program

Test Program Elements

 15 Vehicles, 9 Manufacturers

 3-way Catalyst Technology

 Mix of Cars and Trucks

 Some SFTP Intent Calibrations

 Goal 1 

 Zero sulfur effect

 100, 30, <5 ppm Sulfur (Nominal 2 ppm)

 “Zero” Sulfur Fuel Blended to Meet Predictive Model

 Goal 2

 Oxygenate effect

 30 ppmS sulfur base fuel

 With and without 3.5 wt.% ethanol

 Volatility-Matched (T10, T50 and T90)

 Test Sequence: Start Sulfur Removal Protocol, Test 2 ppmS fuel, 

then in Random order test the three 30 ppmS fuels (PhII, 0% and 

3.5% Oxygen), 100 ppmS fuel, Sulfur Removal Protocol, 2 ppmS 

fuel.

 Common Test Protocol at Each Site

 Production and Production-Intent and SFTP Prototype Vehicles 

Tested at Manufacturer Facilities

 50k or 100k Aged Catalysts

 Independent Statistician for Data Analysis

4-23-99

GAH
Automotive/Petroleum Industry Sulfur/Oxygen Test Program

Participation

Manufacturer Car Truck Total

1. DaimlerChrysler 1 1 2

2. Ford 2 1 3

3. GM 2 1 3

4. Toyota TBD 2

5. Nissan 1 1

6. VW 1 1

7. Honda 1 1

8. BMW 1 1

9. Volvo 1 1

______________________________________________________

Total: 12 3 15

4-23-99

GAH
Updated Tech 5 Sulfur/Oxygenate Proposal -

Automotive/Petroleum Industry Vehicle Test Program

v. 4.1, 4/23/99

Purpose: 1) Provide additional data for CARB (short-term) and EPA (long-term) 

on Fuel Sulfur effects at near-zero sulfur levels for 1996 and later MY 

(Tech 5 category) vehicles. 2) Provide CARB with information on Fuel 

Oxygenate effects for these vehicles.

Objective: 1) Clarify sulfur response function below 30 ppmS fuel sulfur level. 2) 

Define vehicle response to fuel oxygenate levels of ‘0’, 2.0 and 3.5% 

oxygen.

Participation: Worldwide automotive manufacturers, similar to previous 

AAMA/AIAM Sulfur Effects Project of 1997. Preliminary discussions 

have involved AAM (Fuels Working Group), AIAM and CRC 

(Emissions Committee) automotive and oil participants. Each 

manufacturer should endeavor to have at least one or two vehicles 

committed to this program. Some manufacturers have already indicated 

three or four vehicles will be tested. WSPA/API petroleum companies 

are involved as program partners and will supply the blended fuels for 

testing. There are currently nine automobile manufacturers indicating 

test participation.

Vehicles: >1995MY production or production intent three-way catalyst passenger 

cars and light duty trucks. Attempt to include prototype-SFTP compliant 

vehicles. There are presently 15 vehicles indicated for testing, including 

several LD trucks.

Fuels: Sulfur Effects: Near-zero sulfur level of <5 ppmS (nominal 2 ppmS). 

Western States Petroleum Association (WSPA) will provide a very-low 

sulfur base fuel (nominal 2 ppmS) , and this base fuel would be doped 

with di-t-butyl disulfide to obtain sulfur levels of 30 ppmS and 100 

ppmS. Oxygenate Effects: California Phase 2 certification fuel (30 

ppmS typical, 11% MTBE, 2.0% oxygen content) will be used. WSPA 

will supply two additional fuels: a volatility-matched oxygenate-free fuel 

(30 ppmS, 0.0% oxygen) and a volatility-matched 10% ethanol fuel (30 

ppmS, 3.5% oxygen). Optional Fuel: The Federal certification fuel 

(Indolene, typical 30 ppmS, 0% oxygen), which would be supplied by

the OEM along with a full fuel analysis to be included as part of the data.

Time-Frame: To be useful, data needs to be on the table in the July-August timeframe.
Caveat: Sulfur is present in lubricating oils, as similar compounds present in 

fuel, AND as anti-wear additives, such as zinc dithiophosphate. 

Lubricating oil sulfur present in exhaust prevents the emissions control 

system from ever seeing true 'zero' sulfur, even with sulfur-free fuel. 

Normal lubricating oil sulfur contribution is believed to correspond to 'a 

few' ppmS in fuel. Vehicles will be tested with a commercially

lubricating oil. Lubricating oil analyses will be included in data set.

Catalyst Aging:Although aged catalyst hardware is definitely preferable, it is not 

required for participation. Catalysts with 50K mile or 100K mile aging 

levels are to be considered. Engine- or oven-aged catalysts are 

acceptable. Catalyst aging plans need to be supplied at the start of the 

test program.

Catalyst Loading: Earlier AAMA/AIAM test program used a 30-minute idle to load 

catalysts with sulfur. Recent studies on later technology catalysts have 

indicated that that can lead to incomplete catalyst loading. The new 

loading procedure will be 10 back-to-back LA4 driving cycles (75 

vehicle miles), to be performed after going to a new sulfur level fuel.
Sulfur Removal: The 10-WOT cycle from previous programs will be used, with ten 

wide-open throttle accelerations from 30 to 70 mph to drive exhaust hot 

and rich for total of at least 60 seconds (temperature > 700C, Lambda < 

0.9, simultaneous). Added dynamometer horsepower and vehicle 

weight, or engine calibration control, may be necessary to achieve the 

temperature target and rich operation. Sulfur removal would be 

performed when it is necessary to get a vehicle back to it's true baseline 

emissions level, i.e., before and after the sulfur test series.

Per-Vehicle Test Program Outline

# of Vehicles: Each manufacturer will decide how many vehicles will be tested. All 

vehicles should be tested according to the following procedure.

Highest priority: Phase 1: Fuel Sulfur & Oxygenate Effects. 1 vehicle x 5 tests x 5 

fuels (@ `0’, 30, 100 ppmS) = 25 emissions tests per vehicle. The test 

sequence starts with `0’ ppmS, then the three 30 ppmS fuels (0.0, 2.0 

and 3.5% oxygen in randomized order), finishing with 100 ppmS fuel. 

Primary testing is on the FTP emissions cycle. Five repeated FTP tests 

at each sulfur level are desired to minimize test-to-test variability. As a 

fall-back, use Auto/Oil criteria for triplicate testing determination (HC, 

33%; CO, 70%, NOx, 30%). The 10-WOT cycle is necessary with the 2 ppmS 

fuel before starting Phase 1. The 10 LA4 cycles are necessary to assure 

the catalyst is loaded. At the end of this series, the 10-WOT cycle 

should be run to bring the vehicle back to baseline and the 2 ppmS fuel 

emissions tested to assure full baseline return or evaluate any baseline 

offset.

Next priority: Phase 2: Short Term Sulfur Memory Effects. After exposure to 100 

ppmS fuel in Phase 1, retest at 2 ppmS after FTP pre-conditioning until 

emissions performance levels out. Assuming a minimum of 3 tests are 

required for stabilization, 1 vehicle x 3 tests x 2 fuels = 6 tests per 

vehicle. This Phase is to be performed separately from Phase 1.

Lowest priority: Phase 3: Moderate Exposure Memory Effects. Mileage 

accumulation on 100 ppmS fuel. Run 3,000 (or more) miles on AMA 

mileage accumulation procedure. Run two tests with aging fuel after 

mileage accumulation complete, retest at 30 ppmS after FTP preconditioning until emission performance levels out. Assuming 

minimum of 3 tests are required, 1 vehicle x 2 tests (100ppmS) + 1 

vehicle x 3 tests (2 ppmS) = 5 tests per vehicle. Pre-conditioning could 

use US06 cycles in replacement of FTP.

Modeling: Single fuel-parameter variation data will be available in the fuel sulfur 

portion of the program. The entire set of emissions data is combined 
into a tech-group data set, along with the fuels analyses results, similar 

data from earlier test programs, and then a statistical model analysis 

looks for evidence of fuel parameter effects within the combined data 

set.

Statistical Analysis: A statistician (Dr. Richard Gunst, SMU) will be contracted by AAM to 

analyze the sulfur portion of the data set and the oxygenate portion, 

separately. In addition, the data set will be provided to CARB for use in 

their predictive model update.

Version #4.1, RG - 4/20/99