Post on 28-Dec-2015
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