1. Impacts of Natural Gas Fuel Composition on Tailpipe Emissions and Fuel Economy PGOB3113-25 6/15/00 June 2000

2. Test Protocol 7 heavy-duty natural gas-powered test vehicles 7 heavy-duty natural gas-powered test vehicles 4 natural gas test fuels—1 meeting ARB specs 4 natural gas test fuels—1 meeting ARB specs 3 drive cycles 3 drive cycles 3 tests per cycle/fuel/vehicle condition...results shown are averages...additional statistics available 3 tests per cycle/fuel/vehicle condition...results shown are averages...additional statistics available PGOB3113-31a 5/00

3. PGOB3113-29 11/99 Test Fuel Composition METHANEETHANEPROPANEISO-BUTANEN-BUTANEISO-PENTANEN-PENTANE C 6 + C0 2 N 2 OXYGENTOTAL NET HEAT VALUE (BTU/CF) #1 High C 3 + CARB SPEC NG FUEL COMPOSITION Highlighted areas denote out of spec components #2 High Inerts/C 3 + #3 High Ethane #4 Comm. Grade 87.255.843.060.280.550.080.070.052.370.450.00100.0099982.067.113.830.350.630.060.040.004.990.940.00100.0198387.118.251.810.090.170.020.020.011.880.640.00100.0097394.973.020.140.020.020.010.010.000.591.200.03100.00905 Min = 88.00 Max = 6.00 C 3 + Max = 3.00 Range = 1.5-4.5 Max = 1.00

4. Drive Cycles 4 mile, 360 second cycle 4 mile, 360 second cycle 1 acceleration/cruise/deceleration sequence 1 acceleration/cruise/deceleration sequence Commuter PGOB3113-30 11/99 6.3 mile, 1070 second cycle 6.3 mile, 1070 second cycle 6 acceleration/cruise/deceleration/idle sequences...each acceleration to cruise has higher speed 6 acceleration/cruise/deceleration/idle sequences...each acceleration to cruise has higher speed Modified CBD 5.6 mile, 1060 second cycle 5.6 mile, 1060 second cycle 6 different acceleration/cruise/deceleration/idle sequences 6 different acceleration/cruise/deceleration/idle sequences Modified CBD

5. Summary of Emissions Effects Based on the UDDS Cycle PGOB3113-26 11/99

6. NMHC Emissions Closed Loop System PGOB3113-03 1/05/00 Emissions (Grams/Mi) Commercial Grade 0.43 1.411.471.34 Test Vehicle #1: School Bus Engine: MY ‘97 High C 3 + High Ethane High Inerts/ C 3 +

7. PGOB3113-07 1/05/00 Emissions (Grams/Mi) Commercial Grade 1.90 1.791.891.81 Test Vehicle #2: School Bus Engine: MY ‘99 High C 3 + High Ethane High Inerts/ C 3 + NMHC Emissions Closed Loop System

8. PGOB3113-11 1/05/00 Emissions (Grams/Mi) Commercial Grade 1.79 2.742.912.60 Test Vehicle #3: School Bus Engine: MY ‘96 High C 3 + High Ethane High Inerts/ C 3 + NMHC Emissions Closed Loop System

9. PGOB3113-23 1/05/00 Emissions (Grams/Mi) Commercial Grade 1.97 2.872.972.71 Test Vehicle #4: Crew Truck Engine: MY ‘99 High C 3 + High Ethane High Inerts/ C 3 + NMHC Emissions Closed Loop System

10. PGOB3113-36 5/15/00 Emissions (Grams/Mi) Commercial Grade 0.85 3.243.342.71 High C 3 + High Ethane High Inerts/ C 3 + Test Vehicle #5 Tractor Engine: MY ‘99/’00

11. CO Emissions Closed Loop System PGOB3113-01 1/05/00 Test Vehicle #1: School Bus Engine: MY ‘97 Emissions (Grams/Mi) Commercial Grade.26 0.190.220.22 High C 3 + High Inerts/ C 3 + High Ethane

12. CO Emissions Closed Loop System PGOB3113-05 1/05/00 Test Vehicle #2: School Bus Engine: MY ‘99 Emissions (Grams/Mi) Commercial Grade 0.68 0.720.780.75 High C 3 + High Ethane High Inerts/ C 3 +

13. PGOB3113-09 1/05/00 Test Vehicle #3: School Bus Engine: MY ‘96 Emissions (Grams/Mi) Commercial Grade 3.77 4.244.204.22 High C 3 + High Ethane High Inerts/ C 3 + CO Emissions Closed Loop System

14. PGOB3113-21 11/99 Test Vehicle #4: Crew Truck Engine: MY ‘99 Emissions (Grams/Mi) Commercial Grade 3.12 3.543.443.43 High C 3 + High Ethane High Inerts/ C 3 + CO Emissions Closed Loop System

15. PGOB3113-34 5/15/00 Test Vehicle #5: Tractor Engine: MY ‘99/’00 Commercial Grade 6.45 13.487.5310.88 High C 3 + High Ethane High Inerts/ C 3 + CO Emissions Closed Loop System 0 1 2 3 4 5 6 7 8 Emissions (Grams/Mi)

16. PGOB3113-02 1/05/00 Emissions (Grams/Mi) Commercial Grade 7.62 8.167.108.98 Test Vehicle #1: School Bus Engine: MY ‘97 High C 3 + High Ethane High Inerts/ C 3 + NO X Emissions Closed Loop System

17. PGOB3113-06 1/05/00 Emissions (Grams/Mi) Commercial Grade 10.34 13.7912.4212.40 Test Vehicle #2: School Bus Engine: MY ‘99 High C 3 + High Ethane High Inerts/ C 3 + NO X Emissions Closed Loop System

18. PGOB3113-10 1/05/00 Emissions (Grams/Mi) Commercial Grade 11.39 12.5111.0312.84 Test Vehicle #3: School Bus Engine: MY ‘96 High C 3 + High Ethane High Inerts/ C 3 + NO X Emissions Closed Loop System

19. PGOB3113-22 1/05/00 Emissions (Grams/Mi) Commercial Grade 5.96 6.766.076.86 Test Vehicle #4: Crew Truck Engine: MY ‘99 High C 3 + High Ethane High Inerts/ C 3 + NO X Emissions Closed Loop System

20. PGOB3113-35 5/15/00 NO X Emissions Closed Loop System Test Vehicle #5: Tractor Engine: MY ‘99/’00 Emissions (Grams/Mi) Commercial Grade 4.53 6.464.476.10 High C 3 + High Ethane High Inerts/ C 3 +

21. Natural Gas vs Diesel Engines PGOB3113-33 12/99 NG engines deliver higher NMHC and CO emissions CO (grams/mi.) 1.35 Based on: 1997 DD Series 50 (diesel) and 1996 Cummins L10 (natural gas) engines in transit buses on UDDS cycle 9.45 NMHC (grams/mi.) 200% Increase 600% Increase 0.050.16 Diesel Natural Gas Diesel

22. Natural Gas vs Diesel Engines PGOB3113-32 12/99 NG engines deliver lower NO X and particulate emissions NO X (grams/mi.) 18.1 Based on: 1997 DD Series 50 (diesel) and 1996 Cummins L10 (natural gas) engines in transit buses on UDDS cycle 12.3 Particulates (grams/mi.) 75% Reduction 33% Reduction 0.17 0.04 Diesel Natural Gas Diesel