Monitoring and Laboratory Division April 25, 2002 Planning and Technical Support Division Mobile Source Control Division California Air Resources Board
Proposed Control Measure to Reduce Emissions from Small Off-Road Engines
(SORE)
Elements of SORE Control Measure
• Exhaust Element – Revises exhaust emission standards for non-handheld equipment
• Evaporative Element– New evaporative emission standard for walk-behind mowers (WBMs)– Requires new fuel tanks to meet a permeation standard (applicable
to all handheld and non-handheld SORE categories)– Proposing design-based certification requirements
Goals of the Evaporative Element of SORE Control Measure
• Reduce diurnal evaporative emissions from non-handheld equipment by 70% (17.6 TPD)
• Reduce diurnal evaporative emissions from handheld equipment by 40% (1.5 TPD)
• Use readily available technology to reduce emissions• Allow flexible certification requirements to reduce burden on
industry
Status of the Regulatory Effort
• Identified evaporative emission processes• Finalizing OFFROAD emissions inventory• Developed evaporative emission test procedures• Quantified SORE evaporative emissions• Performed emission reduction testing• Developing draft regulatory language
Evaporative Emission Processes
• Running Loss Emissions– Evaporative emissions that occur during equipment
operation
• Hot Soak Emissions– Evaporative emissions that result from latent heat– Typically generated for a one-hour period after equipment
operation
• Diurnal Emissions– Evaporative emissions that result from daily temperature
variations– Includes permeation emissions (fuel line and tank)
Status of Inventory Development
• Contract testing at Automotive Testing Laboratories (ATL) nearly complete
• Will repeat wintertime testing with winter pump fuel (High RVP) to develop temperature correction factor
• Have requested a contract augmentation to perform additional tank replacement testing on handheld and large non-handheld equipment
• Performing data reduction to modify current OFFROAD emission factors
In-House Evaporative Emissions Testing
• Baseline Emissions– Background diurnal emissions from new equipment– Summertime hot soak and diurnal emissions– Summertime ROG emissions using fuel containing ethanol– Fuel tank vented emissions– Wintertime hot soak and diurnal emissions– Fuel tank permeation emissions
• Emissions Reduction Testing– Walk-behind mowers– Barrier treated HDPE fuel tanks
• Manufactured at least one month prior to testing• Emissions less than 0.1 gram/day
Background Diurnal Emissions from New Equipment
0.014 0.016 0.017
0.026
0.066
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
Chainsaw Leaf Blow er String Trimmer Mow er Front Engine Tractor
gram
s H
C/d
ay
• Test fuel - summertime pump (low RVP, ~ 7 PSI)
• Temperature profile - (65°F - 105°F - 65 °F)
• Emissions below 1.0 gram/day except for leaf blowers
Summertime Diurnal Emissions(Handheld Equipment)
0.356
0.673
1.336
0.715
1.500
0.907
1.779
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Chainsaw Hedge Trimmer Leaf Blow er String Trimmer
gram
s H
C/d
ay
• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (1-hour @ 95°F)
Summertime Hot Soak Emissions(Handheld Equipment)
0.097
0.066
0.113
0.071
0.163
0.0800.074
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
Chainsaw Hedge Trimmer Leaf Blow er String Trimmer
gra
ms
HC
/day
• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (65°F - 105°F - 65 °F)• Average diurnal emissions from new mowers 2.312 grams/day
Summertime Diurnal Emissions(Walk-Behind Mowers)
2.068 2.181 2.256 2.289 2.446 2.450 2.495
4.123
7.064
0
1
2
3
4
5
6
7
8
Law nboy Craftsman Craftsman YardMachine
YardMachine
YardMachine
Honda Murray(Used)
Murray(Used)
gra
ms
HC
/day
• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (1-hour @ 95°F)• Average hot soak emissions from new mowers 0.524 grams/day
Summertime Hot Soak Emissions(Walk-Behind Mowers)
0.412
0.5800.546
0.406
0.614 0.632
0.475
0.699
0.528
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Law nboy Craftsman Craftsman YardMachine
YardMachine
YardMachine
Honda Murray(Used)
Murray(Used)
gra
ms
HC
/day
• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (65°F - 105°F - 65 °F)• Large (> 0.5 gal) vented fuel tanks are a major source of emissions
Summertime Diurnal Emissions(Other Non-handheld Equipment)
7.3925.949
1.204
4.123
15.045
7.142
1.846
13.015
0
2
4
6
8
10
12
14
16
Generator Front Engine Tractor Edger Tiller
gram
s H
C/d
ay
Diurnal Emissions from Passively Vented HDPE Off-Road Equipment Fuel Tanks
Grams Hydrocarbons = 2.9579*(Vapor Volume)
Grams Hydrocarbons = 2.3392*(Vapor Volume)
0
2
4
6
8
10
12
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Vapor Volume (gallons)
To
tal H
yd
roc
arb
on
s (
gra
ms
)
Total Hydrocarbons (grams) Reddy Equation Estimate
• Test fuel - summertime pump (low RVP, ~ 7 PSI)
• Temperature profile - (48.5°F - 69.5°F)
• Emissions significantly lower
Wintertime Diurnal Emissions
3.573
2.239
0.8950.526 0.322
0
0.5
1
1.5
2
2.5
3
3.5
4
Generator Front Engine Tractor Mow er Leaf Blow er String Trimmer
gram
s H
C/da
y
Fuel Tank Permeation Emissions(Untreated HDPE Tanks)
• Tanks soaked for 30 Days• Certification fuel used for testing• Subjected to multiple diurnal profiles• Permeation result is the average daily weight loss divided by the
internal surface area• Thick Walled Tanks (> 0.125”)
– Avg. handheld permeation rate (6.39 grams/m2/day)
– Avg. large non-handheld permeation rate (5.92 grams/m2/day)
• Thin Walled Tanks (< 0.125”)– Avg. small non-handheld permeation rate (10.60 grams/m2/day)
Fuel Tank Permeation Emissions(Fluorinated HDPE Tanks)
• 19 Tanks treated to level 5 fluorination• Tanks soaked for 30 days• Certification fuel used for testing• Subjected to multiple diurnal profiles• Permeation result is the average daily weight loss divided by the
internal surface area– Avg. permeation rate ~ 0.84 grams/m2/day
– 92% Level of reduction
• Results for Typical HDPE Mower Tanks • 92% Level of reduction
Comparison of Untreated and Fluorinated HDPE Tanks
9.779.40
10.83
14.32
0.71 0.38 0.08 0.38
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
Tecumseh (0.25 gal) Tecumseh (0.375 gal) B&S (0.25 gal) Honda (0.29 gal)
gram
s H
C/s
quar
e m
eter
/day
Untreated
Treated
Emission Reduction Testing Summary for Walk-Behind Mowers
(WBMs)• Three pairs of popular mower engines tested (B&S
Intek, Tecumseh Magna Torque, Honda GCV 160)• Measured hot soak and diurnal emissions in SHED• Summer pump fuel used for testing• Equipment tested in four phases
– Baseline with no controls, phase I – With fluorinated tank, phase II– With fluorinated tank and PermBlok fuel line, phase III– With fluorinated tank, PermBlok fuel line, and controlled
venting mechanism, phase IV
Phase IV Configured Honda Mower
Mower Evaporative Emission Reduction Results(24-Hour Diurnal)
2.85
2.58
3.26
3.54
2.54 2.51
1.491.40
1.95 2.00
1.551.70
1.11 1.15
1.83 1.83
1.18
1.54
0.640.81
1.020.94
0.84 0.88
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
No Control
Fluorinated Tank
Fluorinated Tank + PermBlok Fuel Line
Fluorinated Tank + PermBlok Fuel Line + Controlled Venting
Proposed1.0 Gram DiurnalStandard
Mower Evaporative Emission Reduction Results(1-Hour Hot Soak)
0.52
0.670.70
0.75
0.47
0.390.41
0.33
0.59
0.73
0.32
0.370.36
0.31
0.49
0.55
0.25
0.35
0.170.15 0.15
0.170.14
0.11
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
B&S #1 B&S #2 Tecumseh #1 Tecumseh #2 Honda #1 Honda #2
Gra
ms
HC
No ControlFluorinated TankFluorinated Tank + PermBlok Fuel LineFluorinated Tank + PermBlok Fuel Line + Controlled Venting
Distribution of Uncontrolled Evaporative Emissions from WBM(Average of 2.879 grams HC per 24-hour Diurnal Test)
1.198
0.242
0.589
0.850
Fuel Tank Permeation (42%)
Fuel Line Permeation (8%)
Fuel Tank Venting (20%)
Cabuertor Venting (30%)
**
** Remaining emissions attributed to carburetor
Previously Proposed Diurnal Standard for WBMs
• Maximum allowable diurnal emissions– (1.0 grams HC/day)
• Result must be obtained with a 40 CFR Part 86 compliant SHED
• Temperature profile - (65°F - 105°F - 65 °F)• Test fuel - California certification fuel• Fill level - tank will be tested at a 50% Fill Level• Diurnal test must be performed after a 1-hour hot soak
test and subsequent 2-hour cold soak at 65 °F
New Proposal
• Design-Based Standard– Requires no SHED testing by manufacturers– Manufacturers not held to a specific numerical standard– Certification protocol to be developed– ARB performs in-use testing
• Design Standards would apply to all non-handheld portable equipment
Example of Design Requirements for WBMs
• Certify by design– Use or specify a fuel tank that is automatically sealed when
equipment is stored– Use or specify a fuel tank that meets a prescribed level of
treatment– Use or specify a SAE 2260 category 1 low permeation fuel
line– Use or specify a tethered fuel cap
Our Estimated Costs of Evaporative Controls
• Cost to Comply with the Permeation Standard ($2.00 - $3.00 per tank)
• Cost to Comply with the Design-Based Standard ($15.00 per unit)– Controlled venting mechanism - ($7.00 - $10.00)– Low permeation fuel line ($2.00)– Compliant fuel tank ($2.00 - $3.00)
• We Request Industry Estimates of the Cost to Produce Equipment that Meets the Proposed Design-Based Requirements
SORE Emissions Inventory and Anticipated Reductions
Estimated 2020 Population
2356902
3263808
1583165
0
500000
1000000
1500000
2000000
2500000
3000000
3500000
Handheld Equipment Walk-Behind Mowers Non-Handheld Equipment (ExcludingWBMs)
Est. 2020 Population
SORE Emissions Inventory and Anticipated Reductions Cont.
Estimated 2020 SORE Emissions TPD
3.7
23.4 23.3
2.2
5.87.0
0.0
5.0
10.0
15.0
20.0
25.0
Handheld Equipment Walk-Behind Mowers Non-Handheld Equipment (ExcludingWBMs)
Est. Uncontrolled Emissions
Est. Controlled Emissions
Estimated 2020 Benefit TPD
1.5
17.6
16.3
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
Handheld Equipment Walk-Behind Mowers Non-Handheld Equipment (ExcludingWBMs)
Est. Benefit TPD
Next Steps
• Conduct Additional Testing– Emission reduction testing with fuel containing ethanol– testing to ascertain barrier durability– Evaporative emission testing with catalysts– Development of wintertime correction factor for the
OFFROAD model
• Develop Certification Procedures and Alternatives• Develop Control Measure Cost Estimate• Draft Proposed Regulatory Language and Staff
Report
Current Schedule
Event or Task Target Date
Additional Testing June, 2002
Draft Regulatory Language July, 2002
Third Workshop September, 2002
Board Consideration December, 2002
Contacts and Additional Information
Evaporative Emissions InformationGeorge Lew (916) 327-0900 [email protected] Bloudoff (916) 323-1169 [email protected] Watson (916) 327-1282 [email protected] (916) 322-2444
Emissions Inventory InformationMark Carlock (626) 575-6608 [email protected] Agrawal (626) 450-6136 [email protected] Wong (626) 450-6184 [email protected]
OREFT WEB Page URLhttp://www.arb.ca.gov/msprog/offroad/sore/sore.htm
Conceptual WBM Certification Scenario
EngineManf.
Fuel TankManf.
Fuel LineOEM
Certifies VentingMechanism
CertifiesTank @ Level
5
Certifies use ofLow Perm Fuel
Line
OEM Integrator
Submits One CertificationApplication
Fuel TankTreatment
Facility
ARB Approves Design
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