Larger vehicles will remain available in 2025, despite CAFE

  • 25-Nov-2013 08:10 EST

Stepped curves show how larger vehicle footprints reduce fuel-economy requirements for cars and trucks. This was done to meet Congressional mandates to maintain a similar size vehicle fleet for the future. Each year's CAFE line is slightly higher than the previous one.

Conventional wisdom says the performance-car parts industry can look for an onslaught of smaller and smaller cars and light trucks, and once gasoline prices go past $4 or $5, plug-in hybrids and full-electric vehicles "will fly off the lots." Just myths, said Sandy Stojkovski, President of Scenaria Inc., an AVL company, at a 2013 SEMA Show forum in Las Vegas Nov. 18.

Fuel-economy regulations and the projected 54.5 mpg CAFE (corporate average fuel-economy) number for 2025 actually encourage production of bigger vehicles, she said.

Think her company doesn't understand the regulations? AVL is the largest independent engineering services company in the world. Scenaria is its strategic planning company, using models to visualize complex technology, to sort through the facts to separate "the hype from the reality."

Curves are the regulation

Yes, makers of passenger cars and light trucks have to increase fuel economy substantially, even if they take advantage of off-cycle CAFE credits. But it won't be easy.

It's all based on stepped EPA/NHTSA curves on graphs tied to each vehicle model's "footprint"—wheelbase multiplied by track width, in square feet. Points on model year curves align with fuel economy and footprint axes on the graphs.

Those curves are the regulation, and they represent careful EPA/NHTSA research. The 54.5 mpg is a projection of the fuel economy of the vehicles that will be sold in 2025, based on the curves. A company must align the average footprints of its vehicles with the right points on the curves for cars and trucks to satisfy the fuel-economy regulations.

In theory, a maker of only large light-duty trucks (footprint of 75 ft²) might satisfy the 2025 regulation at about 28 mpg, whereas a maker only of small (42 ft²) economy cars would have to post an average of almost 60 mpg. Volume makers produce full lines, so full-fleet sales projections are where the 54.5 mpg CAFE comes from. That's a NHTSA number; EPA makes equivalent projections in CO2 g/mi. The curves are "harmonized," meaning NHTSA curves reflect EPA estimates of special off-cycle A/C credits for low-global-warming refrigerant and low-leakage A/C sealing, two CO₂ issues.

Another factor is the California regulation that, by 2025, 15% of all cars sold must be zero emission—i.e., electric vehicles (EVs), with partial credits for plug-in hybrids (PHEV). The actual EV number required could go higher because 10 Northeast states and Washington, D.C., normally follow California's regulations. EVs get high-MPG equivalent numbers, which help car makers boost their overall averages.

'Breaks' in the curves 

Do you think of the Fiesta and Focus as just Ford "econo-cars"? The difference from the slightly larger size of the Focus serves as an example. Fiesta's footprint is under 39 ft²; Focus is 44 ft². However, the Fiesta is on the top plateau of the stepped curve; its 2025 CAFE number is almost 60 mpg. The Focus is on the downward slant and its CAFE number is in the 57 mpg range. Comparison: Taurus is 51 ft² and its CAFE number is about 48-49 mpg.

CAFE includes the same off-cycle credits for such technologies as idle-stop and A/C efficiency upgrades that improve fuel economy, regardless of vehicle footprint, so the impact is more beneficial for larger vehicles. Further, CAFE is based on the old city and highway tests, which yield higher numbers than shown on window stickers derived from a total of five driving tests.

Do the graphs represent some unintended consequences? Absolutely not, according to EPA and NHTSA specialists to whom AEI spoke. They follow Congressional mandates intended to ensure the regulations "would not turn the fleet into small cars and scooters," was one specialist's comment.

Yes, the curve requires a lower percentage increase in fuel economy at some larger vehicle sizes, but maintaining approximately the same sizes of vehicles in the fleet was the Congressional directive that EPA and NHTSA had to follow. The regulators also had to consider effects from tighter emissions standards for larger cars and greater difficulty, perhaps entailing extra weight, if new safety regulations were promulgated.

"The curves were not designed as incentives to upsize or downsize," a NHTSA specialist explained.

Truck fuel-economy numbers curve lower than cars, so they have an easier path. This was intentional, because a truck has to be capable of doing work, and increasing capability often translates to larger size and more weight. So many car-type crossovers get all-wheel-drive, because that may help a car maker define it as a truck. This aspect of the truck definition also was intentional.

"We had to recognize AWD increases work capability," so it's part of the truck definition, a NHTSA specialist said.  

Stojkovski compared the 2012 compact Chevrolet Colorado/GMC Canyon pickup with a 2.9-L four-cylinder listed at 44.5 ft² with a 2013 Silverado/Sierra hybrid pickup with a 6.0-L V8 listed at 67.8 ft². To meet 2025 CAFE, the 2012 Colorado/Canyon, rated at 27.1 mpg, would have to top 44 mpg, a 39% improvement. The 2013 Silverado/Sierra hybrid would have to go from 21.5 to 30.5 mpg, a 29.5% increase. This is an example (Focus vs. Fiesta is another) of why Stojkovski said that 2025 CAFE standards actually encourage production of larger vehicles and more trucks.

Scenaria projects the 2025 incremental cost of a PHEV at about $12,000 over conventional gasoline engine technology, so "PHEVs fell off the chart" in terms of practical affordability, even for a compact car. A pure EV, with comparable range, also wouldn't make the affordability cut.

She acknowledged that a number of EVs and PHEVs will be built to meet the 15% zero-emissions vehicle requirements set by California and likely to be followed by Northeastern states. However, EVs might have to be sold at a loss, for "at cost" wouldn't be cost-effective for a buyer, she said. And, she added, they aren't needed to meet 2025 CAFE.

Similar powertrains in 2025

Although fuel cells, natural gas engines, carbon-fiber body parts, and HCCI (homogeneous-charge compression ignition) gasoline engines are being promised, the conventional car fleet won't use these technologies in significant volume, Stojkovski told the SEMA audience. In fact, Scenaria predicts powertrain technology similar to what is currently in use.

To meet regulations most cost-effectively (absent new technologies that may emerge), the 2025 "compact car" engine will be a downsized, typically four-cylinder, with a turbocharger, direct fuel injection, and idle stop-start. The transmission will be eight-speed, likely a dry-clutch dual-clutch gearbox. Rolling resistance will be lowered further, aerodynamics improved, and, she estimates, just a 3% reduction in vehicle weight. The increased cost of these changes will be $2350—not the $1800 originally estimated by the EPA. The CAFE number of that econocar will be 57.8 mpg, she added, which will produce window sticker mpg numbers in the mid-40s.

American consumers buy smaller, more economical cars for a number of reasons, some cost-based, but hybrids for the feel-good aspect of high fuel economy. A Prius buyer gets satisfaction from its 50 mpg, even if he can't justify the price premium for the savings.

Hybridization for performance

High performance is likely to employ hybridization, she said, as a cost-effective path to difficult targets for socially acceptable luxury vehicles. Further, it was shown as a practical approach for the recently completed Clemson University International Center for Automotive Research project car, a low- to medium-priced AWD concept based on a turbocharged Mazda front-drive powertrain combined with a rear-drive electric drivetrain.

The prevailing impression is that gasoline engines will become increasingly complex. Stojkovski offered this alternative thought: A byproduct of hybridization may be simpler gasoline engines, because they could operate in their most optimum rpm band, deriving less value from variable valve lift and timing.

Stojkovski buried another myth that the "mid-term review of the fuel-economy standards could quickly lead to major changes." If there are any changes of note from this review, scheduled for 2018, the lead-time requirements mean they will not affect vehicles earlier than at least 2022, she said.

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