Mobile Source Control Division November 13, 2002 Planning and Technical SupportMonitoring and Laboratory DivisionCalifornia Air Resources Board

Proposed Control Measure to Reduce Emissions from Small Off-Road Engines

(SORE)

Major Components of the Evaporative Portion of the Proposed SORE Control

Measure• Sets diurnal evaporative emission standards for equipment with

engine displacements greater 65 cc

• Sets a fuel tank permeation standard applicable to all SORE categories

• Requires manufactures to label and certify equipment sold in California

Regulatory Approach

• Use available technology to reduce emissions

• Set attainable and cost effective emission standards

• Limit burden on industry by:– Providing either a performance or a design-based certification option– Allowing a phased-in implementation schedule

Permeation Technology

• Multi layered co-extruded (Coex) plastic fuel tanks• HDPE fuel tanks made with Selar® RB-425• Post fabrication fluorination of HDPE fuel tanks• Post fabrication sulfonation of HDPE fuel tanks• Metal fuel tanks• Fuel connectors made from acetal copolymers and other

low permeation thermoplastics• Fluoroelastomer seals, diaphragms and gaskets

Barrier Treatment Permeation Comparison

Selar® RB-425 vs. Fluorination and Co-ex with EVOH

9.00

7.00

0.150.50

0.150.60

0.10 0.40

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

gram

s/ta

nk/d

ay

HDPE RB-425 F2 CO-EX

Haltermann15M + 5E

Permeability of fuel tanks containing with 7% Selar® and 30% regrind using a 65 - 105 -65° F diurnal profile.Average values for Fluorination (F2) and co-ex with EVOH.

0.12 0.353.00

65.00

26.00

0

10

20

30

40

50

60

70

g-m

m/m

2-d

ay

PPS POM PBT HDPE Nylon

Fuel CE10 @ 40° C

Polymer Permeation Comparison

•Polyphenylene Sulfide (PPS), Acetal Copolymer (POM)

•Polybutylene Terephthalate (PBT)

0.3 0.4 2.2 3.6

56.45

0

10

20

30

40

50

60

g-m

m/m

2-d

ay

Zytel 450 Zytel 70G33 Zytel 103 Zytel ST801 HDPE

Fuel CE10 @ 40° C

Nylon Permeation Comparison

Dupont Zytel® Nylon Products

Evaporative Emission Control Technology

• Passively actuated valves that control vapors• Carbon canisters systems that absorb tank vapors• Pleated carbon air filters capable of absorbing

carburetor vapors• Hybrid systems that vent tank vapors to a canister

above a fixed pressure• Collapsible fuel bladders

Venting Control Technology Demonstration

• Tested three pairs of walk-behind lawn mowers• ARB built and tested prototype controls with the

following technology:– Engine-brake actuated valves that isolate tank vapors during

storage– Fluorinated HDPE fuel tanks– Low permeation fuel lines

Modified Snapper Mower

Modified Honda Mower

Venting Technology Demonstration DataLawn Mower Evaporative Emission Reduction Data

(24-Hour Diurnal Fuel Comparison)

2.969

3.374 3.414

2.963

3.777

1.2511.356

0.782

3.149

0.809 0.8140.861

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

B&S #1 B&S #2 Tecumseh #1 Tecumseh #2 Honda #1 Honda #2

Gra

ms

HC

Baseline MTBE Baseline Ethanol Modified MTBE Modified Ethanol

ProposedStandard

Canister Control Technology Modeling

• Calculated emissions from a 670 cc canister with a working capacity of 36 grams

• Modeled canister performance as if it were attached to a 5 gallon fuel tank filled to 50% capacity

• Assumed a test fuel with a RVP of 7 PSI• Simulated canister performance over 50 diurnal

temperature profiles (65 - 105 - 65°F)• Worst case long term efficiency determined to be 47%

Canister Modeling Data

0

1

2

3

4

5

6

7

8

9

10

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

Day

Gra

ms

HC

Tank Emissions Absorbed by Canister Backpurge Canister Emissions

Proposed >225 cc 2.0 gram Standard

7 Day Design Criteria

Estimated Canister Efficiency

97%

50.6%

47.4%

0

10

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

Day

Effici

ency

%

Canister Efficiency

Proposed Evaporative Standards

• 1.0 gram HC/day diurnal standard for equipment with engines > 65 cc < 225 cc

• 2.0 gram HC/day diurnal standard for equipment with engines > 225 cc

• 1.0 gram/meter2/day fuel tank permeation standard for all SORE equipment fuel tanks

Test Procedures

• Staff is reviewing recently adopted U.S. EPA permeation and diurnal emissions test procedures

• TP-901, “Test Procedure for Determining Fuel Tank Permeation Rates Using Gravimetric Analysis”:– currently considering a gravimetric test procedure

• TP-902, “Test Procedure for Determining Diurnal Evaporative Emissions from Small Off-Road Engines”– is intended for performance-based certification

• Requesting comment on alternative test procedures

In-Use Durability Test

• Staff is developing a test procedure that duplicates the cycles of use of systems/components

• Test procedure currently assumes 7 year useful life• Accelerated aging would simulate usage and consider

hour of operation• Staff is currently seeking comment on durability test

procedures

Certification Options

• Certify equipment to performance standards (CP-901 Part I)

• Certify equipment to design standards (CP-901 Part II)

• Certify control components/systems (CP-901 Part III)– Fuel tank permeation (CP-901 Appendix A)– Venting control (CP-901 Appendix B)– Fuel hose permeation (CP-901 Appendix C)

Performance-Based Certification Overview

OEM SubmitsCover Letter and

CertificationApplicationper CP-901

ARB AcceptsCertificationApplication

ARB Reviews TestData and Performs

EngineeringEvaluation

ARB ReviewsApplication

ARB RejectsCertificationApplication &Notifies OEM

MeetsPerformanceStandards?

ARB DeniesCertification and

Notifies OEM

ARB PreparesCertification

Summary, IssuesExecutive Order

and Notifies OEM

Deficient Complete

No Yes

OEM SubmitsLetter of Intent

per CP-901

PerformanceStandards or

OptionalPerformance

Standards

Reference

Performance-Based Certification Requirements

• Group equipment models into evaporative families

• Measure emissions for the highest emitting equipment within the evaporative family

• Submit an evaporative emissions label for ARB approval

• Submit a certification application that includes:– Performance-based certification summary sheet– Certification Database Form

Performance-Based Testing Requirements

• Performance-based certification requires gravimetric testing (all SORE tanks) and SHED testing for engines > 65 cc– Select a model in the evaporative family that is expected to

exhibit worst-case emissions– Conduct emission testing per applicable test procedure

TP-901 or TP-902– Results must not exceed applicable standard

Design-Based Certification Overview

ARB Accepts LOC

ARB EvaluatesLOC

ARB ReviewsLOC

ARB Rejects LOC& Notifies OEM

ApprovedComponents?

ARB DeniesCertification and

Notifies OEM

ARB StampsApproved on

LOC and NotifiesOEM

Deficient Complete

No Yes

OEM SubmitsLetter of Intent

per CP-901

OEM SubmitsLetter of

Compliance (LOC)per CP-901

List of ApprovedFuel Tank Designs

per CP 901Appendix A

Executive Order

List of ApprovedComponent

Designs per CP901 Appendix BExecutive Order

List of ApprovedFuel Line Designs

per CP 901Appendix C

Executive Order

Reference

Design-Based Certification Requirements

• Select approved emission control equipment

• Group equipment into evaporative families

• Submit an evaporative emissions label for ARB approval

• Submit a letter of compliance that includes:– Design-based certification summary sheet– Certification database form

Design-Based Certification Summary Sheet Requirements

• Certification Summary must specifically reference:– Executive Order number from CP-910 Appendix A that

approves the fuel tank permeation control – Executive Order number from CP-901 Appendix B that

approves the system used to control vapors generated by the fuel tank

– Executive Order number from CP-901 Appendix C that approves the low permeation fuel line

Design-Based Equipment Requirements

• Control equipment must include:– Fuel tank permeation control – System to control vapors generated by the fuel tank– Self-locking, tethered fuel cap– Low permeation fuel line that meets SAE J30 R11, J30

R12A, or J2260 category one specifications

Control System Certification Overview

ARB AcceptsApplication

ARB PerformsEngineering

Evaluation andReviews Test Data

ARB ReviewsApplication

ARBRejectsApplication& Notifies Manf.

TechnologyCertified

ARB DeniesCertification andNotifies Manf.

ARB CertifiesTechnology withConditions and

Issues ExecutiveOrder

Deficient Complete

No Yes

ManufacturerSubmits

Application forCertification with

Test Data

Applicable DesignCriteria in

Appendixes A, B,or C

Test DataCompared to

ApplicablePerformance

Standards

Durability DataDocuments no

Significant Increasein Emissions

ReferenceCriteria

Control System Certification Process

• Submit a certification application containing:– cover letter with test data– engineering description of control system– durability demonstration– statement of materials compatibility with fuels– any maintenance requirements– warranty

• System will undergo an engineering evaluation that may include:– evaluation of system concept– bench testing of components– failure mode testing

Next Steps

• Incorporate stakeholder comment on proposed regulatory language and certification procedures

• Post and take comment on test procedures TP-901 and TP-902

• Prepare staff report

Contacts and Additional Information

Evaporative Emissions InformationJames Watson (916) 327-1282 jwatson@arb.ca.govDean Bloudoff (916) 323-1169 dbloudof@arb.ca.govFax (916) 322-2444

Emissions Inventory Information

Walter Wong (626) 450-6184 wwong@arb.ca.govArchana Agrawal (626) 450-6136 aagrawal@arb.ca.govMark Carlock (626) 575-6608 mcarlock@arb.ca.gov

SORE Web Page URLhttp://www.arb.ca.gov/msprog/offroad/sore/sore.htm