Expanded file -- July 2, 2003 1 ARB – Exhaust Emissions – Tier 3 Small Off-Road Engine Workshop – Expanded file EMA / OPEI Engine Manufacturers Association

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


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


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


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 %


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 %



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



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


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.



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



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


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.


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


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 ?



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



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.


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


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% )


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


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


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


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


SwRI – B&S Intek Catalyst SystemSwRI – B&S Intek Catalyst System


SwRI – B&S Intek Catalyst SystemSwRI – B&S Intek Catalyst System


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


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


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


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


Tem

per

atu

re (

°F)

TEC2-STK TEC2 Cat C (remote)


Note: Catalyst Remote Mounted


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


Te

mp

era

ture

(°F

)

TEC2-STK TEC2 Cat C (remote)




SwRI – SwRI – Honda GCV160Honda GCV160

Emission Strategies– No Enleanment

• Manufacturer concerns with startability


– 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


SwRI – Honda GCV160SwRI – Honda GCV160


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


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



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


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



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


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



SwRI – Honda GCV160SwRI – Honda GCV160


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.


SwRI – SwRI – Kawasaki FH601V Kawasaki FH601V (V-Twin)(V-Twin)

Emission Strategies– Enleanment – A/F Ratio modified

• Engine sensitive to intake air temp/humidity


– 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


SwRI –Kawasaki CatalystSwRI –Kawasaki Catalyst


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


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



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


Te

mp

era

ture

(°F

)

KAW2-STK KAW2 Cat E



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


Te

mp

era

ture

(°F

)

KAW2-STK KAW2 Cat E



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


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


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)



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


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


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


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


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


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


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


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


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


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


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.

Documents

Expanded file -- July 2, 2003 1 ARB – Exhaust Emissions – Tier 3 Small Off-Road Engine Workshop – Expanded file EMA / OPEI Engine Manufacturers Association