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 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.


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.


Selective Purchase - 2003 FC by Class

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Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models.


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.


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).


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.


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.


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.


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.


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.


Additional Detail and Expanded Explanations of Technical Issues


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.


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.


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).


Selective Purchase (2003 FE by Class)

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Selective Purchase (2003 FC by Class)

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Selective Purchase (2003 FC Range)

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Minimum Diesel Minimum CNGMinimum LPG Minimum E85



Selective Purchase (2003 CO2 by Class)

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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%


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.”


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?


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.


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.


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).


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.


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.


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.


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%.


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.

righg.raabassociates.org/articles/fleets_meszler.ppt

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