Impacts of Natural Gas Fuel Composition on Tailpipe Emissions and Fuel Economy

1
Impacts of Natural Gas Fuel Composition on
Tailpipe Emissions and Fuel Economy
June 2000
PGOB3113-25 6/15/00
2
Test Protocol

• 7 heavy-duty natural gas-powered test vehicles
• 4 natural gas test fuels1 meeting ARB specs
• 3 drive cycles
• 3 tests per cycle/fuel/vehicle condition. .
  .results shown are averages. . .additional
  statistics available

PGOB3113-31a 5/00
3
Test Fuel Composition
NG FUEL COMPOSITION
CARB SPEC
1 High C3
2 High Inerts/C3
3 High Ethane
4 Comm. Grade
87.25 5.84 3.06 0.28 0.55 0.08 0.07 0.05 2.37 0.45
0.00 100.00 999
82.06 7.11 3.83 0.35 0.63 0.06 0.04 0.00 4.99 0.94
0.00 100.01 983
87.11 8.25 1.81 0.09 0.17 0.02 0.02 0.01 1.88 0.64
0.00 100.00 973
94.97 3.02 0.14 0.02 0.02 0.01 0.01 0.00 0.59 1.20
0.03 100.00 905
METHANE ETHANE PROPANE ISO-BUTANE N-BUTANE ISO-PEN
TANE N-PENTANE C6 C02 N2 OXYGEN TOTAL NET HEAT
VALUE(BTU/CF)
Min 88.00 Max 6.00
C3 Max 3.00
Range 1.5-4.5
Max 1.00
PGOB3113-29 11/99
4
Drive Cycles
Commuter

• 4 mile, 360 second cycle
• 1 acceleration/cruise/deceleration sequence

Modified CBD

• 6.3 mile, 1070 second cycle
• 6 acceleration/cruise/deceleration/idle
  sequences. . .each acceleration to cruise has
  higher speed

Modified CBD

• 5.6 mile, 1060 second cycle
• 6 different acceleration/cruise/deceleration/idle
  sequences

PGOB3113-30 11/99
5
Summary of Emissions Effects Based on the UDDS
Cycle
PGOB3113-26 11/99
6
NMHC EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 1 School Bus Engine MY 97
1.41
1.47
1.34
High C3
High Ethane
High Inerts/ C3
PGOB3113-03 1/05/00
7
NMHC EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 2 School Bus Engine MY 99
1.79
1.89
1.81
High C3
High Ethane
High Inerts/ C3
PGOB3113-07 1/05/00
8
NMHC EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 3 School Bus Engine MY 96
2.74
2.91
2.60
High C3
High Ethane
High Inerts/ C3
PGOB3113-11 1/05/00
9
NMHC EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 4 Crew Truck Engine MY 99
2.87
2.97
2.71
High C3
High Ethane
High Inerts/ C3
PGOB3113-23 1/05/00
10
NMHC EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 5 Tractor Engine MY 99/00
3.24
3.34
2.71
High C3
High Ethane
High Inerts/ C3
PGOB3113-36 5/15/00
11
CO EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 1 School Bus Engine MY 97
Commercial Grade .26
0.19
0.22
0.22
High C3
High Inerts/ C3
High Ethane
PGOB3113-01 1/05/00
12
CO EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 2 School Bus Engine MY 99
Commercial Grade 0.68
0.72
0.78
0.75
High C3
High Ethane
High Inerts/ C3
PGOB3113-05 1/05/00
13
CO EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 3 School Bus Engine MY 96
4.24
4.20
4.22
High C3
High Ethane
High Inerts/ C3
PGOB3113-09 1/05/00
14
CO EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 4 Crew Truck Engine MY 99
3.54
3.44
3.43
High C3
High Ethane
High Inerts/ C3
PGOB3113-21 11/99
15
CO EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 5 Tractor Engine MY 99/00
13.48
7.53
10.88
High C3
High Ethane
High Inerts/ C3
PGOB3113-34 5/15/00
16
NOX EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 1 School Bus Engine MY 97
8.16
7.10
8.98
High C3
High Ethane
High Inerts/ C3
PGOB3113-02 1/05/00
17
NOX EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 2 School Bus Engine MY 99
13.79
12.42
12.40
High C3
High Ethane
High Inerts/ C3
PGOB3113-06 1/05/00
18
NOX EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 3 School Bus Engine MY 96
12.51
11.03
12.84
High C3
High Ethane
High Inerts/ C3
PGOB3113-10 1/05/00
19
NOX EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 4 Crew Truck Engine MY 99
6.76
6.07
6.86
High C3
High Ethane
High Inerts/ C3
PGOB3113-22 1/05/00
20
NOX EmissionsClosed Loop System
Emissions (Grams/Mi)
Test Vehicle 5 Tractor Engine MY 99/00
6.46
4.47
6.10
High C3
High Ethane
High Inerts/ C3
PGOB3113-35 5/15/00
21
Natural Gas vs Diesel Engines
NG engines deliver higher NMHC and CO emissions
CO (grams/mi.)
NMHC (grams/mi.)
600 Increase
200 Increase
1.35
9.45
0.05
0.16
Diesel
Diesel
Natural Gas
Natural Gas
Based on 1997 DD Series 50 (diesel) and 1996
Cummins L10 (natural gas) engines in transit
buses on UDDS cycle
PGOB3113-33 12/99
22
Natural Gas vs Diesel Engines
NG engines deliver lower NOX and particulate
emissions
NOX (grams/mi.)
Particulates (grams/mi.)
33 Reduction
18.1
0.17
75 Reduction
12.3
0.04
Diesel
Diesel
Natural Gas
Natural Gas
Based on 1997 DD Series 50 (diesel) and 1996
Cummins L10 (natural gas) engines in transit
buses on UDDS cycle
PGOB3113-32 12/99