Expanded file -- July 2, 2003 1
ARB ARB – Exhaust Emissions –– Exhaust Emissions – Tier 3Tier 3
Small Off-Road Engine Workshop – Expanded file
EMA / OPEIEngine Manufacturers Association / Outdoor Power Equipment Institute
Clean Air Act Committee
Expanded file -- July 2, 2003 2
ARB ARB – Exhaust Emissions –– Exhaust Emissions – Tier 3Tier 3
Production Catalyst Systems– Small Off-Road Engine experience
ARB Test Program– Southwest Research Institute
High Efficiency Catalysts– Thermal energy management
Expanded file -- July 2, 2003 3
Small Off-Road Engine -Production Catalyst SystemsSmall Off-Road Engine -Production Catalyst Systems
International Catalyst System – B&S– Quantum & Mod. 9/10 Side valve
• 1.3 in3 ceramic -or- wire mesh substrate• 10-15% Engine Displacement
– 20-30% HC+NOx Efficiency (0 hrs)• 2-3 g/hp-hr (minimum)
– 10-15% CO Efficiency (0 hrs)• Tier I Carburetor calibration (moderate CO levels)• 50 g/hp-hr CO conversion (maximum)• Limited secondary air / controlled heat release
– International Market Product Feature
Expanded file -- July 2, 2003 4
Average Emissions - Quantum International Catalyst System -0 hr data ( 1.3 in Catalyst )
8.17
1.63
9.80
6.14
1.10
7.24
289
254
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
HC (g/hp-hr) NOx (g/hp-hr) HC+NOx (g/hp-hr) CO (g/hp-hr)
HC
- N
Ox
- HC
+NO
x
0
25
50
75
100
125
150
175
200
225
250
275
300
325
350
SWC
O (g
/hp-
hr)
Engine Out Catalyst Out
26 %
12 %
Expanded file -- July 2, 2003 5
Average Emissions - Quantum International Catalyst System -125 hr data ( 1.3 in Catalyst )
13.84
1.75
15.59
12.78
1.74
14.53
302294
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
HC (g/hp-hr) NOx (g/hp-hr) HC+NOx (g/hp-hr) CO (g/hp-hr)
HC -
NOx
- HC+
NOx
0
25
50
75
100
125
150
175
200
225
250
275
300
325
350
SWC
O (g
/hp-
hr)
Engine Out Catalyst Out
3 %7 %
Expanded file -- July 2, 2003 6
Small Off-Road Engine -Production Catalyst SystemsSmall Off-Road Engine -Production Catalyst Systems
Tecumseh TVM220• 21.8 in3 Vertical L-Head• Certified EPA Phase II • 4.2 in3 Reducing Catalyst / 19% Engine Displacement• 15% HC+NOx Efficiency at 0 Hours
Tecumseh H35• 9.5 in3 Horizontal L-Head• Certfied EPA Phase I, CARB Tier II• 4.2 in3 Reducing Catalyst / 44% Engine Displacement• 29% HC+NOx Efficiency at 0 Hours
Expanded file -- July 2, 2003 7
Small Off-Road Engine -Production Catalyst SystemsSmall Off-Road Engine -Production Catalyst Systems
Emission Sentry System - Kohler– Automotive type system
• 12.2 in3 substrate / 50% of Engine displacement• LPG application• 3-way catalyst loading
– Full Engine control unit• Closed-loop feedback fuel control• O2 sensor
– Low CO levels / High NOx reductions– Low volume production– High-end commercial market
Expanded file -- July 2, 2003 8
ARB / SwRI Test ProgramARB / SwRI Test Program
Emission Strategies– Enleanment (2 of 5 engines)
• Modified to improve catalyst efficiency - SwRI• Increased NOx / Reduced HC• Engine performance/durability concerns
– Secondary Air (all 5 engines)
• Needed to achieve target HC reductions - SwRI• Increased CO% efficiency / energy release• 40 to 60% CO conversion (4 of 5 engines)• B&S Intek #2 - 29% CO converted @ 0 hrs.
Expanded file -- July 2, 2003 9
ARB / SwRI Test ProgramARB / SwRI Test Program
Emission Strategies– Large Metallic Catalyst substrates
(4 of 5 engines)
• ensured substrate mechanical/emission durability
• 75% to more than 185% of engine displacement
• Removed all sound reduction and cooling chamber capacity => “Catalyst container” per SwRI – Honda GCV160 retained cooling
• B&S Intek #2 - 32% of engine displacement catalyst
Expanded file -- July 2, 2003 10
ARB / SwRI Test ProgramARB / SwRI Test Program
Emission Strategies– Remote mounted containers (3 of 5 engines)
• Provided “package space” for Secondary Air
• Reduced engine/ catalyst temperature interaction
– Reduced catalyst system temperatures
• pre-catalyst, substrate mid-bed, container surface & exhaust temperatures
• Reduced vibration interaction – system durability• Both B&S Inteks close mounted
Expanded file -- July 2, 2003 11
Catalyst Secondary Air –Catalyst Secondary Air – % CO reductions% CO reductions
Automotive closed loop fuel systems use feed-back from various sensors to trim or adjust the mixture to the chemically-correct strength for maximum catalyst efficiency
Small Off-road air cooled engine will use simple fixed carburetors, set at the best compromise for performance and life.
Expanded file -- July 2, 2003 12
Catalyst Secondary Air –Catalyst Secondary Air – % CO reductions% CO reductionsE xhaust Tem perature R ise from C O
Oxidation
0
100
200
300
400
500
600
700
0 10 20 30 40 50 60 70 80 90 100
Catalyst Efficiency (%)
Te
mp
era
ture
Ris
e (
De
g F
)
11 :112 :113 :1
Air to Fuel Ratio
Expanded file -- July 2, 2003 13
Catalyst Secondary Air –Catalyst Secondary Air – % CO reductions% CO reductionsEngine
DescriptionHC + NOx
% CO % Exhaust Temp
Surface Temp
1 – Honda . Stock
8.79 293 850-424 570-350
Cat J w/o secondary air
5.92 33% 241 27% Temps Not Recorded
504-304 Remote Mounting
Cat J with secondary air
2.51 71% 108 63% 763-418 685-465
2 B&S Intek 2 . Stock
9.45 307 815-385 618-352
Cat L w/o secondary air
6.70 29% 269 12% 799-548 580-441
Cat L with secondary air
4.08 57% 218 29% 846-596 568-407 Thermo- couple ?
Expanded file -- July 2, 2003 14
Catalyst Secondary Air –Catalyst Secondary Air – % CO reductions% CO reductionsEngine
DescriptionHC + NOx
% CO % Exhaust Temp
Surface Temp
3 –Tecumseh . Stock
7.58 361 Temps not Recorded
Temps not Recorded
Cat C w/o secondary air
3.93 48% 197 45% 842-450 765-591 Remote Mounting
Cat C with secondary air
2.79 63% 169 53% 964-550 810-668
3 –Tecumseh . Stock
9.93 397 916-490 871-607 Stock Temps @ 250 hrs.
Cat C with secondary air
3.76 62% 240 40% 956-625 884-750 Remote Mounting
Expanded file -- July 2, 2003 15
Catalyst Secondary Air –Catalyst Secondary Air – % CO reductions% CO reductionsEngine
DescriptionHC + NOx % CO % Exhaust
TempSurface Temp
4 –Kawasaki . Stock
7.455.51+1.94
380 847-408 Temps not Recorded
Cat E w/o secondary air
4.82 35% 264 30% 1040-560 649-427
Tier 3 Jet secondary air
7.433.55+3.89
0% 226 41% 524-330 Temps not Recorded
Thermo- couple ?
Cat E with secondary air
2.89 61% 106 53%
vs 226
1110-623 468-397 Thermo- couple ?
4 - Kawasaki . Stock
6.705.59+0.81
422 749-380 480-307 Stock Temps @ 125 hrs.
Tier 3 Jet secondary air
7.933.77+4.16
-18% 199 53% 808-364 553-362 Enleanment
= Temp rise
Cat E with secondary air
1.45 82% 123 38% 1080-683 725-538 Temps vs.
0 hrs.
Expanded file -- July 2, 2003 16
SwRI – SwRI – Briggs & Stratton Intek #1Briggs & Stratton Intek #1
Emission Strategies– Enleanment - A/F Ratio modified
• Performance and Durability concerns
– Passive Secondary Air Injection• Increased HC and CO efficiency
• Increased Thermal energy release
– 9.0 in3 Substrate = 75% of displacement• Replaced Stock Muffler with SLT Optional
Muffler
• Removed sound/cooling chambers
• Catalyst “container” only
Expanded file -- July 2, 2003 17
Catalyst Gas Temperatures - SwRI B&S #1 ( 0 hrs )
1309
1264
1221
11811204
1100
1038
967
884 897
1309 1302 1300 13031321
800
900
1000
1100
1200
1300
1400
1500
1600
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Te
mp
era
ture
(°F
)
B&S #1 -Jet #2 (muffler-in) B&S #1 (pre-catalyst) B&S #1 (mid-bed)
Cat C = 59% CO Efficiency = 133 g/hp-hr Ave Weighted Temp (mid-bed) = 1304°F Ave Weighted Temp Increase => +342°F ( +36% )
Ave Weighted Temp (muffler-in) = 1224°F Ave Weighted Temp (pre-cat) = 962°F Ave Weighted Temp Decrease = -262°F ( -21% )
Expanded file -- July 2, 2003 18
Exhaust Gas Temperatures - SwRI B&S # 1 ( 0 hrs )
767
655
542
409
337
856
760
666
581
506
200
300
400
500
600
700
800
900
1000
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Tem
per
atu
re (
°F)
B&S #1-STK B&S #1 Cat C
Cat C = 59% CO Efficiency = 133 g/hp-hrAve Weighted Temp Increase => +135°F ( 26% ) from 529°F to 664°F
Expanded file -- July 2, 2003 19
Muffler Skin Temperatures - SwRI B&S #1 ( 0 hrs )
675
622
539
471438
770
721
671
629 614
200
300
400
500
600
700
800
900
1000
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Te
mp
era
ture
(°F
)
B&S #1-STK B&S #1 Cat C
Cat C = 59% CO Efficiency = 133 g/hp-hr Ave Weighted Temp Increase => +133°F ( 25% ) from 540°F to 673°F
Expanded file -- July 2, 2003 22
SwRI – SwRI – Tecumseh OVRM120Tecumseh OVRM120
Emission Strategies– No Enleanment
• Engine close to recommended Temperature limits
– Passive Secondary Air Injection• Increased HC and CO efficiency• Increased Thermal energy release
– 9.0 in3 Substrate = 75% of engine displacement• Replaced Stock Muffler with Briggs & Stratton SLT
Optional Intek Muffler• Removed sound/cooling chambers• Catalyst “container” only• Location modified away from engine to allow room
for passive air system
Expanded file -- July 2, 2003 23
Catalyst Gas Temperatures - SwRI Tecumseh OVRM120 #2 ( 250 hrs )
1208
1111
10731045 1035
1425
13371318 1302 1290
800
850
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
1550
1600
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Tem
per
atu
re (
°F)
TEC2-STK (muffler-in) TEC2 Cat C (mid-bed)
Cat C = 40% CO Efficiency = 157 g/hp-hrAverage Weighted Temperature Increase => +172°F ( 16% ) from 1082°F to 1325°F
Pre-catalyst Temps not measured by SwRI
Expanded file -- July 2, 2003 24
Exhaust Gas Temperatures - SwRI Tecumseh OVRM120 #2 ( 250 hrs )
916
759
655
556
490
956
830
751698
625
0
200
400
600
800
1000
1200
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Tem
per
atu
re (
°F)
TEC2-STK TEC2 Cat C (remote)
Cat C = 40% CO Efficiency = 157 g/hp-hrAverage Weighted Temperature Increase => +103°F ( 16% ) from 657°F to 760°F
Note: Catalyst Remote Mounted
Expanded file -- July 2, 2003 25
Muffler Skin Temperatures - SwRI Tecumseh OVRM120 #2 ( 250 hrs )
871
793
738
657607
884
812786 776
750
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Te
mp
era
ture
(°F
)
TEC2-STK TEC2 Cat C (remote)
Cat C = 40% CO Efficiency = 157 g/hp-hrAverage Weighted Temperature Increase => +68°F ( 9% ) from 727°F to 795°F
Note: Catalyst Remote Mounted
Expanded file -- July 2, 2003 26
SwRI – SwRI – Honda GCV160Honda GCV160
Emission Strategies– No Enleanment
• Manufacturer concerns with startability
– Passive Secondary Air Injection• Increased HC and CO efficiency• Increased Thermal energy release
– 9.0 in3 Substrate = 92% of engine displacement• Increased muffler/container size 2 times• Removed sound reduction capability• Catalyst “container” with mixing/cooling chambers• Location modified away from engine to allow room
for passive air system
Expanded file -- July 2, 2003 28
Catalyst Gas Temperatures - SwRI Honda GVC160 ( 0 hrs )
1274
1194
1117
1087
1003
1437
1359
1250
1203
1147
800
850
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Tem
per
atu
re (
°F)
Honda-STK (muffler-in) Honda Cat J (mid-bed)
Cat J = 63% CO Efficiency = 185 g/hp-hrAverage Weighted Temperature Increase => +138°F ( 12% ) from 1130°F to 1268°F
Pre-catalyst Temps not measured by SwRI
Expanded file -- July 2, 2003 29
Exhaust Gas Temperatures - SwRI SwRI Honda GVC160 ( 0 hrs )
845
700
590
494
418
766
655
552
479
413
0
200
400
600
800
1000
1200
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Tem
per
atu
re (
°F)
Honda-STK Honda Cat J (remote)
Cat J = 63% CO Efficiency = 185 g/hp-hrAverage Weighted Temperature Increase / Decrease => -33°F ( -6% ) from 593°F to 560°F
Note: Catalyst Remote Mounted
Expanded file -- July 2, 2003 30
Muffler Skin Temperatures - SwRI SwRI Honda GVC160 ( 0 hrs )
571
508
441393
350
698
631
556505
449
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Te
mp
era
ture
(°F
)
Honda-STK Honda Cat J (remote)
Cat J = 63% CO Efficiency = 185 g/hp-hrAverage Weighted Temperature Increase => +116°F ( 26% ) from 445°F to 561°F
Note: Catalyst Remote Mounted
Expanded file -- July 2, 2003 32
SwRI –Honda GCV160SwRI –Honda GCV160
Heat is Dissipated from extension pipe and Muffler.
Heat is Dissipated from extension pipe and Muffler.
Catalyst has been moved away from engine.
Catalyst has been moved away from engine.
Expanded file -- July 2, 2003 33
SwRI – SwRI – Kawasaki FH601V Kawasaki FH601V (V-Twin)(V-Twin)
Emission Strategies– Enleanment – A/F Ratio modified
• Engine sensitive to intake air temp/humidity
– Passive Secondary Air Injection• Increased HC and CO efficiency• Increased Thermal energy release
– 77 in3 Substrate =190% of engine displacement• Removed sound reduction capability• Catalyst “container” with mixing/cooling
chambers• Location modified away from engine to allow
room for passive air system
Expanded file -- July 2, 2003 35
Catalyst Gas Temperatures - SwRI Kawasaki FH601V #2 ( 0 hrs )
1208
1111
10741048 1041
1423
13351317 1303 1293
800
850
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
1550
1600
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Tem
per
atu
re (
°F)
KAW2-STK KAW2 Cat E
Cat E = 51% CO Efficiency = 115 g/hp-hrAverage Weighted Temperature Increase => +241°F ( 22% ) from 1083°F to 1324°F
Pre-catalyst Temps not measured by SwRI
Expanded file -- July 2, 2003 36
Exhaust Gas Temperatures - SwRI Kawasaki FH601V #2 ( 0 hrs )
828
737
641
534
423
1101
1016
884
743
627
0
200
400
600
800
1000
1200
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Te
mp
era
ture
(°F
)
KAW2-STK KAW2 Cat E
Cat E = 51% CO Efficiency = 115 g/hp-hrAverage Weighted Temperature Increase => +240°F ( 38% ) from 628°F to 868°F
Expanded file -- July 2, 2003 37
Muffler Skin Temperatures - SwRI Kawasaki FH601V #2 ( 125 hrs )
478437
397
339305
707 694
614
545510
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Te
mp
era
ture
(°F
)
KAW2-STK KAW2 Cat E
Cat E = 51% CO Efficiency = 115 g/hp-hrAverage Weighted Temperature Increase => +222°F ( 57% ) from 391°F to 614°F
Expanded file -- July 2, 2003 38
SwRI – SwRI – Briggs & Stratton Intek #2Briggs & Stratton Intek #2
Emission Strategies– No Enleanment– Passive Secondary Air Injection
• Increased HC and CO efficiency• Increased Thermal energy release
– 3.7 in3 Substrate = 31% of engine displacement• Replaced Stock Muffler with SLT Optional Muffler• Removed sound/cooling chambers• Catalyst “container” only
Baseline vs. Developed– New Baseline vs. Oct ’02 – Increased HC– Potential Fuel/Oil contamination
Expanded file -- July 2, 2003 39
Catalyst Gas Temperatures - SwRI B&S #2 ( 0 hrs )
1283
1222
1166
1077
987
1091
1039
991
915
839
1252
11931163 1150
1174
700
800
900
1000
1100
1200
1300
1400
1500
1600
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Te
mp
era
ture
(°F
)
B&S #2-STK (muffler-in) B&S #2 (pre-catalyst) B&S #2 Cat L (mid-bed)
Cat L = 29% CO Efficiency = 89 g/hp-hr Ave Weighted Temp (mid-bed) = 1174°F Ave Weighted Temp Increase => +199°F ( +20% ) (est)
Ave Weighted Temp (muffler-in) = 1147°F Ave Weighted Temp (pre-cat) = 975°F (est) Ave Weighted Temp Decrease = -172°F ( -15% ) (est)
Pre-catalyst Temps not measured by SwRI
Expanded file -- July 2, 2003 40
Exhaust Gas Temperatures - SwRI B&S # 2 ( 0 hrs )
815
702
592
462
385
846
760
690641
596
200
300
400
500
600
700
800
900
1000
1100
1200
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Tem
per
atu
re (
°F)
B&S #2-STK B&S #2 Cat L
Cat L = 29% CO Efficiency = 89 g/hp-hr (1174°F Ave mid-bed Temp) Average Weighted Temperature Increase => +118°F ( 20% ) from 578°F to 696°F
B&S #1 Cat C Ave Weighted Exh Temp = 664°Fw/ 133 g/hp-hr converted and 1304°F Ave mid-bed Temps
Expanded file -- July 2, 2003 41
Muffler Skin Temperatures - SwRI B&S #2 ( 0 hrs )
618
537
484
415
352
568
518
470
427407
200
300
400
500
600
700
800
100% Load - 9% 75% Load - 21% 50% Load - 31% 25% Load - 32% 10% Load - 7%
Te
mp
era
ture
(°F
)
B&S #2-STK B&S #2 Cat L
Cat L = 29% CO Efficiency = 89 g/hp-hr (1174°F Ave mid-bed Temp) Average Weighted Temperature Increase => -5°F ( -1% ) from 476°F to 471°F
B&S #1 Cat C Ave Weighted SkinTemp = 673°Fw/ 133 g/hp-hr converted and 1304°F Ave mid-bed Temps
Expanded file -- July 2, 2003 42
Ignition Time vs. Temp – selected Forest FuelsIgnition Time vs. Temp – selected Forest FuelsU.S Dept of Agriculture, Forest ServiceU.S Dept of Agriculture, Forest Service
Temp Material Time Noted Effect
518°F Punky Wood 5 min. Smoke, Glowing, Combustion
518°F Cheat Grass 5 min. Substantial Browning
572°F Cheat Grass 3 min. Smoke
518°F Sawdust 10 min. Smoke & Browning
Expanded file -- July 2, 2003 43
Catalyst Application Catalyst Application - SORE- SORE
Reference Ignition Temp, Gasoline
850°F Fire Protection Handbook, 14th Edition
Gasoline Ignition on Hot Surface, Open Air
1250°F API PSD 2216, 1980
Max Exposed Surface Temp, Combustion
550°F U.S.D.A. Forest Service, SAE J335
Max Exhaust Gas Temp, Combustion
475°F U.S.D.A. Forest Service, SAE J335
Max Exposed Surface Temp, Skin Burns
175°F DIN Standards, B&S
Expanded file -- July 2, 2003 44
Catalyst Application Catalyst Application – Small Off-Road Engines– Small Off-Road Engines
Safe & Functional Design Criteria Increased Temperatures
– Exhaust gas & surface “Over-Rich” conditions
– Choke, primers, dirty air cleaners Field Application concerns
– Temperatures, Fuel spillage, Debris V-twin & High Inertia applications
– Additional Problems
Expanded file -- July 2, 2003 45
Catalyst Application Catalyst Application - Performance- Performance
System durability w/application – High % Class 2 sold w/o mufflers– “Best-in-Class” vs. Mass Market
Catalyst durability/reliability– Thermal Failures
• Sintering, Melting, Loosening
– Poisoning• Metallic Oil additives
Expanded file -- July 2, 2003 46
Catalyst Application Catalyst Application – Other Major Issues– Other Major Issues
Application Concerns– Increased package size, shielding,
weight– Increased development / qualification to
ensure compliance – Emissions & Safety– Reduced reliability & Increased
variability ( 2 systems => engine/catalyst )
– OEM “Add-on” – Certification & audit– Increased costs – component &
equipment
Expanded file -- July 2, 2003 47
Catalyst Application Catalyst Application – Cost Impact– Cost Impact
High conversion efficiency will require new engines (new tooling)
– Current average engine-out levels in production must be met by nearly all production units if high-efficiency converters are to perform according to design
– Thermal management for safety and engine durability
Other impacts– Equipment manufacturers– California consumers and businesses
Expanded file -- July 2, 2003 48
ARB ARB – Exhaust Emissions – – Exhaust Emissions – Tier 3Tier 3
High HC+NOx conversion efficiency catalysts are not possible without high CO conversion efficiency.
Thermal Management Engine & Equipment manufacturers
cannot meet standards based on high conversion efficiency without major engine and equipment modifications – New tooling for most lawn & garden
engines not an add-on package.