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Transcript of righg.raabassociates.org/Articles/Fleets_Meszler.ppt
Fleet GHG Performance
An Overviewof Issues and Options
Transportation Work GroupPhase III - Meeting 1
October 30, 2003
Meszler Engineering Services906 Hamburg DriveAbingdon, Maryland 21009
410-569-0599www.meszler.com
Meszler Engineering Services Page 2 October 30, 2003
Viable Fleet GHG Reduction Options
• Selective purchase.
– Purchase carbon efficient vehicles -- high fuel efficiency, low carbon fuel.
– Current market offers vehicles with a range of fuel efficiency in all vehicle classes.
• Undertake aftermarket efficiency improvements (aftermarket = after manufacturer delivery).
• Implement a rigorous maintenance program.
• Control VMT/speed.
Meszler Engineering Services Page 3 October 30, 2003
Selective Purchase Options
• Select the smallest, most fuel efficient vehicle that will do the job (FC increases with vehicle mass).
• Select vehicles powered by low carbon fuels:
– Diesel: 22.4 pounds CO2 per gallon consumed– Gasoline: 19.5 pounds CO2 per gallon consumed– E85: 14.9 pounds CO2 per gallon consumed
– CNG: 14.1 pounds CO2 per gallon consumed (1)
– LPG: 13.5 pounds CO2 per gallon consumed
(1) CNG is based on 121.5 ft3 per gallon equivalent (U.S. DOT).All others are liquid gallon figures.
Meszler Engineering Services Page 4 October 30, 2003
Selective Purchase - 2003 FC by Class
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Maximum Gas/Diesel/HEV Median Gas/Diesel/HEVMinimum Gas/Diesel/HEV Minimum GasolineMinimum Diesel Minimum CNGMinimum LPG Minimum E85
Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models.
Meszler Engineering Services Page 5 October 30, 2003
EPACT Purchase Implications
• EPACT - Limits flexibility of state (and fuel provider) fleets.
• NG options are generally low GHG.
– Reductions of 10-20% could be achieved by purchase of lowest consumption gasoline vehicles in the large car and pickup truck classes (limited NG availability).
• E85 generally a poor choice (poor fuel efficiency).
• Must use the EPACT fuel to get GHG benefits.
Meszler Engineering Services Page 6 October 30, 2003
Aftermarket Efficiency Improvements
• Some aftermarket technologies are superior to others from a GHG perspective.
• Advanced lubricating oils reduce GHG relative to higher viscosity alternatives.
– Friction reduction (up to 3% GHG benefit).
• Tire design can also reduce GHG.
– Reduced rolling resistance (up to 6% GHG benefit).
Meszler Engineering Services Page 7 October 30, 2003
Improved Maintenance (a)
• Maintenance can significantly impact GHG.
• A proper tune-up can improve FC by 4-30%
– Improvement depends on severity of need (high end of range is associated with malperforming O2 sensor -- low end of range typical).
• A dirty air filter can increase FC by as much as 10% through increased air restriction.
Meszler Engineering Services Page 8 October 30, 2003
Improved Maintenance (b)
• Under-inflated tires can increase FC by about 1% for every 3 psi.
– An 8/01 NHTSA study found that about 30% of light duty vehicles had at least one tire under-inflated by 8 psi or more.
– Average under-inflation was about 1 psi for PC and 2 psi for LT.
Meszler Engineering Services Page 9 October 30, 2003
Operational Changes (a)
• Operational characteristics directly affect GHG.
• VMT.
– VMT reductions translate into direct GHG reductions, but are difficult to implement and enforce.
• Reduced vehicle idling.
– Idling restrictions are in place in many jurisdictions, but enforcement varies.
Meszler Engineering Services Page 10 October 30, 2003
Operational Changes (b)
• Aggressive driving and speed also strongly influence fuel consumption and GHG.
• Increase in FC (from 55 mph) is about:
– 3% at 60, 10% at 65, 20% at 70, 30% at 75
• Nationally, 20% of VMT is >55 mph.
Meszler Engineering Services Page 11 October 30, 2003
Model for State Fleet Legislation
• In California, SB552 (Burton) requires (pending signature) the state to adopt standards:
– To dispose of nonessential SUVs and 4WD pickups from the state fleet.
– To use low carbon fuel in state bi-fuel vehicles.
– To purchase best-in-class vehicles.
• Upcoming NESCAUM presentation will provide additional information on activity in other states.
Meszler Engineering Services Page 12 October 30, 2003
Additional Detail and Expanded Explanations of Technical Issues
Meszler Engineering Services Page 13 October 30, 2003
General Methods to Reduce GHG (a)
• Vehicle technology improvement - decrease fuel consumption (FC) per mile (or per minute at idle).
– Generally this translates to an increase in fuel economy, but fuel consumption decreases at a slower rate than fuel economy (FE) increases.
– For small changes in FE, the difference between FE and FC change is small -- but significant for larger changes.
– 15% FE increase is 13% FC decrease, but 50% and 100% FE increases are 33% and 50% FC decreases.
Meszler Engineering Services Page 14 October 30, 2003
General Methods to Reduce GHG (b)
• Select the smallest vehicle that will do the job (FC increases with vehicle mass).
• Select vehicles powered by low carbon fuels:
– Diesel: 22.4 pounds CO2 per gallon consumed– Gasoline: 19.5 pounds CO2 per gallon consumed
– CNG: 14.1 pounds CO2 per gallon consumed (1)
– LPG: 13.5 pounds CO2 per gallon consumed
– E85: 14.9 pounds CO2 per gallon consumed
(1) CNG is based on 121.5 ft3 per gallon equivalent (U.S. DOT).All others are liquid gallon figures.
Meszler Engineering Services Page 15 October 30, 2003
General Methods to Reduce GHG (c)
• To determine overall GHG impact, use of reduced carbon fuel must also consider:
– Any impact on overall FC.
– Any change in methane (CH4) or nitrous oxide (N2O) emissions (1 g CH4 = 21 g CO2, 1 g N2O = 310 g CO2)
• Improve performance of “off-cycle” technology.
– E.g., air conditioning energy demand or reduced GHG refrigerant (neither are considered in current CAFE requirements --- 1 g HFC134a = 1300 g CO2).
Meszler Engineering Services Page 16 October 30, 2003
Selective Purchase (2003 FE by Class)
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Minimum Gas/Diesel/HEV Median Gas/Diesel/HEVMaximum Gas/Diesel/HEV Maximum GasolineMaximum Diesel Maximum CNGMaximum LPG Maximum E85
Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models.
Meszler Engineering Services Page 17 October 30, 2003
Selective Purchase (2003 FC by Class)
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Maximum Gas/Diesel/HEV Median Gas/Diesel/HEVMinimum Gas/Diesel/HEV Minimum GasolineMinimum Diesel Minimum CNGMinimum LPG Minimum E85
Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models.
Meszler Engineering Services Page 18 October 30, 2003
Selective Purchase (2003 FC Range)
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n) Maximum Gas/Diesel/HEV Median Gas/Diesel/HEVMinimum Gas/Diesel/HEV Minimum Gasoline
Minimum Diesel Minimum CNGMinimum LPG Minimum E85
Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models.
Meszler Engineering Services Page 19 October 30, 2003
Selective Purchase (2003 CO2 by Class)
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Maximum Gas/Diesel/HEV Median Gas/Diesel/HEVMinimum Gas/Diesel/HEV Minimum Gasoline
Minimum Diesel Minimum CNGMinimum LPG Minimum E85
Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models.
Meszler Engineering Services Page 20 October 30, 2003
Selective Purchase (2003 CO2 Range)
-60.0%
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Maximum Gas/Diesel/HEV Median Gas/Diesel/HEVMinimum Gas/Diesel/HEV Minimum Gasoline
Minimum Diesel Minimum CNGMinimum LPG Minimum E85
Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models.
Meszler Engineering Services Page 21 October 30, 2003
Best/Worst Gasoline AT Vehicles - 2003Minimum Fuel Consumption Maximum Fuel Consumption
Vehicle ClassMake/Model/Displacement/Transmission gal/100 mi Make/Model/Displacement/Transmission gal/100 mi
Max FC/Min FC
Subcompact Car Toyota Celica - 1.8L (A-4) 3.12 Ford Mustang - 4.6L (A-4) 5.00 +60%
Compact Car Toyota Echo - 1.5L (A-4) 2.78 Infiniti G35 - 3.5L (A-S5) 4.76 +71%
Midsize Car Honda Accord - 2.4L (A-5) 3.57Hyundai XG350 - 3.5L (A-5)Oldsmobile Aurora - 4L (A-4)
5.00 +40%
Large Car Chevrolet Impala - 3.4L (A-4) 4.00Ford Crown Victoria - 4.6L (A-4)Lincoln Town Car - 4.6L (A-4)Mercury Grand Marquis - 4.6L (A-4)
5.00 +25%
Passenger Van
Chevrolet Astro 2WD - 4.3L (A-4)Chevrolet G1500/2500 Chevy Express 2WD - 4.3L (A-4)GMC G1500/2500 Savana 2WD - 4.3L (A-4)GMC Safari 2WD - 4.3L (A-4)
5.88
Chevrolet Astro AWD - 4.3L (A-4)Chevrolet G1500/2500 Chevy Express 2WD - 5.3L (A-4)Chevrolet H1500 Chevy Express AWD - 5.3L (A-4)Ford E150 Club Wagon - 4.2L (A-4)Ford E150 Club Wagon - 5.4L (A-4)GMC G1500/2500 Savana 2WD - 5.3L (A-4)GMC H1500 Savana Van AWD - 5.3L (A-4)GMC Safari AWD - 4.3L (A-4)
6.67 +13%
Cargo VanChevrolet Astro 2WD - 4.3L (A-4)GMC Safari 2WD - 4.3L (A-4)
5.26Dodge Ram 2500 Van 2WD - 3.9L (A-3)Dodge Ram 2500 Van 2WD - 5.9L (A-4)Ford E150 Econoline 2WD - 5.4L (A-4)
7.14 +36%
MinivanChrysler Voyager/Town&Country 2WD - 2.4L (A-4)Dodge Caravan 2WD - 2.4L (A-4)
4.35 Kia Sedona - 3.5L (A-5) 5.88 +35%
2WD SUV Toyota Rav4 2WD - 2L (A-4) 3.85
Cadillac Escalade 2WD - 5.3L (A-4)Chevrolet C1500 Avalanche 2WD - 5.3L (A-4)Chevrolet C1500 Suburban 2WD - 5.3L (A-4)Chevrolet C1500 Tahoe 2WD - 5.3L (A-4)Dodge Durango 2WD - 5.9L (A-4)Ford Expedition 2WD - 5.4L (A-4)GMC C1500 Yukon 2WD - 5.3L (A-4)GMC C1500 Yukon XL 2WD - 5.3L (A-4)Lincoln Aviator 2WD - 4.6L (A-5)
6.67 +73%
4WD SUVHonda CR-V 4WD - 2.4L (A-4)Subaru Forester AWD - 2.5L (A-4)Toyota Rav4 4WD - 2L (A-4)
4.17
Cadillac Escalade AWD - 6L (A-4)Cadillac Escalade ESV AWD - 6L (A-4)Cadillac Escalade EXT 4WD - 6L (A-4)Dodge Durango 4WD - 5.9L (A-4)GMC K1500 Yukon AWD - 6L (A-4)GMC K1500 Yukon XL AWD - 6L (A-4)Lexus LX 470 - 4.7L (A-5)Toyota Land Cruiser Wagon 4WD - 4.7L (A-5)
7.14 +71%
2WD PickupFord Ranger 2WD - 2.3L (A-5)Mazda B2300 2WD - 2.3L (A-5)
4.17Dodge Dakota Pickup 2WD - 5.9L (A-4)Dodge Ram 1500 Pickup 2WD - 5.9L (A-4)
6.67 +60%
4WD Pickup Toyota Tacoma 4WD - 2.7L (A-4) 5.26Dodge Dakota Pickup 4WD - 5.9L (A-4)Dodge Ram 1500 Pickup 4WD - 5.9L (A-4)GMC K1500 Sierra Denali AWD - 6L (A-4)
7.14 +36%
Meszler Engineering Services Page 22 October 30, 2003
Selective Purchase and Displacement (a)
• Much of fuel consumption difference is due to engine size options within classes. Lower GHG generally correlates with lower engine size.
– Vans are exception, but range of GHG is generally less as well.
– So, potential of selective purchase depends on minimum engine size needed to do “the job.”
Meszler Engineering Services Page 23 October 30, 2003
Selective Purchase and Displacement (b)
• How much difference does displacement make?
• Example, 4WD SUV -- best vs. worst -- Honda CR-V vs. Dodge Durango -- Durango has 71% higher CO2 emissions and costs about $8K more:
• The differences are clear, but does it transport more than people?
Meszler Engineering Services Page 24 October 30, 2003
Aftermarket Efficiency Improvements
• Some aftermarket technologies are superior to others.
– Energy consumption influences for a given operational demand are: engine thermal efficiency, friction and pumping losses, drivetrain losses, accessory loads, vehicle mass, aerodynamic drag, and rolling resistance.
– Of these, engine friction and rolling resistance can be affected by aftermarket technology.
• Friction loss can be improved through advanced lube oil, rolling resistance through tire design.
Meszler Engineering Services Page 25 October 30, 2003
Advanced Lubricating Oils (a)
• Low viscosity lube oils have become widely available.
– 10W and 5W oils are dominant, and 0W is on the market (#W indicates winter viscosity, with lower #s indicating increased fluidity -- lower friction).
– Reduced viscosity 10W-20, 5W-30, and 5W-20 formulations widely available, along with 0W-20 (the second # indicates summer viscosity, with with lower #s indicating increased fluidity -- lower friction).
– 5W-30 is the dominant factory fill oil, with significant use of 5W-20 -- the Honda Insight uses 0W-20.
Meszler Engineering Services Page 26 October 30, 2003
Advanced Lubricating Oils (b)
• Maintaining factory fill oil will not improve FC, but moving to more advanced grades can provide benefits.
– 1% or so from 10W-30 to 5W-30 ($0.20-$0.30/quart).– 1% or so from 5W-30 to 5W-20 ($0.25-$0.50/quart).– Another 1% or so from 5W-20 to 0W-20 ($1.50+/qt).
• Benefits dependent on age and current practice.
– Newer vehicles with advanced factory fill oil will see least benefit, except in cases where current practice results in in-use degradation (higher viscosity).
Meszler Engineering Services Page 27 October 30, 2003
Rolling Resistance Improvements (a)
• Rolling resistance (RR) is a measure of the force required to overcome tire structural inertia and road friction.
– Low rolling resistance (LRR) tires require less energy to induce a given vehicle movement.
• Generally the ratio between FC and RR is about 1:6 -- a 1% reduction in FC for every 6% reduction in RR.
Meszler Engineering Services Page 28 October 30, 2003
Rolling Resistance Improvements (b)
• OEMs recognize the benefits of LRR (for CAFE) and most original equipment tires exhibit coefficients of RR (Cr) is the range of 0.008-0.012 (lower Cr means higher efficiency).
• Performance tires and large truck tires can exhibit Cr in the range 0.011-0.014.
• There is some trade off between LRR and acceleration/braking performance and OEMs balance tire selection accordingly.
Meszler Engineering Services Page 29 October 30, 2003
Rolling Resistance Improvements (c)
• However, styling is also a factor and tires wider than required for safety or performance are often used on larger vehicles.
• Moreover, tire replacement seldom considers RR, or even maintaining factory-level specifications.
• A 1/03 California Energy Commission study found replacement tire Cr to be within the ranges previously noted -- but consumers have no way to identify high RR from LRR tires.
Meszler Engineering Services Page 30 October 30, 2003
Rolling Resistance Improvements (d)
• In response to this lack of information, California passed AB844 (nation) requiring tire efficiency labeling in the state beginning in 2008.
• In the interim, Green Seal (an environmental organization) has published a list of recommended LRR replacement tires, with Cr from 0.0062 to 0.0105.
– The upper end of the range is typical of factory tire performance; the lower end a FC reduction of ~7%.
Meszler Engineering Services Page 31 October 30, 2003
Rolling Resistance Improvements (e)
• For a 185/70R14 tire, Cr=0.006-0.0085 tires are about $35 more expensive than Cr=0.009-0.0105.
– Similar cost delta exists for a 235/75R15 with Cr=0.008 versus Cr=0.009.
• As with advanced lube oil, actual benefits will depend on current tire replacement practice.