Some surprises arise from three-year NRC study

Say the National Highway Traffic Safety Administration (NHTSA) – which, for some strange reason, administers the feds' Corporate Average Fuel Economy (CAFE) program – wanted to know what the true costs would be of virtually every ICE fuel-saving technology. What would it do?

If NHTSA folks were smarter than your average overpaid government bureaucrats, they might commission the National Research Council (NRC) to assemble a group of actual experts to study available technologies and compare costs vs. effectiveness. And, amazingly, they did.

The resulting three-year study, "Assessing Fuel Economy Technologies for Light Duty Vehicles," provides educated estimates of fuel consumption benefits vs. costs for 40-some technologies that are commercially available and implementable within five years. It was released this June, and – because one distinguished member of NRC's study committee was Dr. Jay Baron, president and CEO of the Ann Arbor, Mich. Center for Automotive Research (CAR) – a one-page preview was available at CAR's August Management Briefing Seminars (this post continues after the jump).

The CAR one-pager said:
Many experts don't expect battery electric vehicles will achieve mass market acceptance for at least 10 to 15 years – or longer without continued economic stimulus or a technology breakthrough – both risky propositions. In North America, the internal combustion engine will likely remain the primary powertrain for the next 15 years, capable of burning gasoline or alternative bio-fuels. Many [fuel-saving] technologies are technically feasible, but constrained by high cost.
The study concludes that a traditional gasoline engine with a portfolio of advanced technologies can reduce its fuel consumption by about 29 percent at an added (consumer) cost of $2,200. To compare, an advanced "clean" diesel engine offers a 38 percent reduction at an average added cost of $5,900 and a full hybrid a hefty 44 percent improvement for $6,000.

Accompanying CAR's summary is a chart ranking 28 of those technologies available now or soon by their incremental cost to the vehicle buyer per one percent fuel-economy improvement. The first thing you'll notice is that many of the technologies listed (e.g., multi-gear transmissions, vehicle mass reduction, aerodynamic improvement) are not engine but vehicle-related. The second is that many affect the same energy-consuming elements, and some are further advancements of others, so they are definitely not additive.

SI Techs AVG Incremental Cost Avg Cost for 1% Improvement in Fuel Consumption
Low Viscosity Lubricants $6 $12.00
VVT-Coupled Cam Phasing (CCP), OHV $53 $21.00
Variable Stroke HVAC $80 $22.86
Turbocharging and Downsizing $129 $25.80
Low Rolling Resistance Tires $40 $26.67
Aerodynamics 5%-10% $45 $30.00
Electric/Hydraulic Power Steering $95 $31.67
Valve Event Manipulation $52 $34.67
7 Speed Transmission $235 $39.17
VVT-Coupled Cam Phasing (CCP), SOHC $105 $42.00
VVT-Dual Cam Phasing (DCP) $105 $46.67
Dual Clutch Transmission $350 $46.67
Continuous Variable Transmission $207 $51.63
8 Speed Transmission $425 $60.71
Valve Event Manipulation (Variable Value Lift) $760 $69.09
VVT-Intake Cam Phasing (ICP) $105 $70.00
Cylinder Deactivation, OHV $353 $70.50
Engine Friction Reduction $95 $75.60
Continuously Variable Valve Lift (CVVL) $450 $90.00
Mass Reduction 5% $297 $91.38
Mass Reduction 10% $713 $109.69
Cylinder Deactivation, SOHC $555 $111.00
Full Hybrid $6,000 $127.66
Discrete Variable Valve Lift (DVVL), SOHC/DOHC $293 $130.00
Mass Reduction 20% $1,600 $133.33
Stoichiometric Gasoline Direct Injection (GDI) $319 $141.78
Conversion from SI to CI $5,900 $159.46
Stop/Start Hybrid $885 $221.25

At the very top is low-viscosity lubricants at an average incremental cost of just $12 per one percent fuel consumption improvement. Next comes coupled cam phasing (variable valve timing, or VVT), which varies both intake and exhaust valve timing simultaneously, on an OHV (pushrod) engine at $21 per one percent gain.

Downsizing engines and adding turbocharging to recover lost performance – which, coupled with direct fuel injection, Ford markets as EcoBoost – falls a surprising fourth on the chart at about $26 per one percent. Just below that are low-rolling-resistance tires at about $27, a 10-percent aerodynamic drag reduction at $30 and electro/hydraulic power steering (vs. conventional hydraulic) at nearly $32.

Second from the bottom is that $5,900 diesel at nearly $160 per one percent improvement. At the very bottom is a stop/start hybrid, fairly affordable at $885 total but costing a hefty $221 per one percent. By contrast, the $6,000 full hybrid system is nearly twice as cost effective at about $128 per one percent efficiency gain.

Looking at various valvetrain enhancements, dual cam phasing is good for about $47, variable valve lift (VVL) comes in at $69 and cylinder deactivation of a pushrod engine – General Motors ' Active Fuel Management (AFM), Chrysler's Multi-Displacement System (MDS) – at just over $70 per one percent. A seven-speed automatic transmission (presumably vs. the once-common four-speed) adds roughly $39, a dual-clutch gearbox $47, a CVT (continuously variable transmission) $52 and an eight-speed automatic $61 per one percent improvement. Further down the chart are vehicle mass reductions of five percent ($91 per one percent), 10 percent ($110) and 20 percent ($133) and gasoline direct injection at about $142.

What all this means is that, as CAFE requirements accelerate upward over the next several years, each automaker will have to pick and chose from a menu of such fuel-saving technologies and decide which combinations are most cost-effective. Then we, as potential buyers, will compare and decide which models from which makers will best suit our needs while delivering the best fuel efficiency at the most affordable prices.

For those willing to pay a nominal feel for the NRC's entire massive stack of information and data, or specific elements of it, go here.

Some readers of my last column jumped on GM Hybrid and Powertrain Engineering Executive Director Larry Nitz' challenge to rival Nissan's Leaf BEV to duplicate his 256-mile Volt-driven trek from Detroit to Traverse City. He (accurately) said, "It will take you two days to get up here, because you've got to stop and recharge and stop and recharge."

Months earlier, at a sustainability seminar, Toyota USA Advanced Product Technology National Manager Bill Reinert had defended his company's coming plug-in Prius' 13-mile electric-only range vs. the Leaf's claimed 100 miles: "If you want to visit Grandma driving the Leaf, can you do that?" he had asked, according to Ward's AutoWorld magazine. He continued:
As long as she lives within 50 miles, because you've got to come home. And if you're going to drive on the freeway, that reduces your (range). And are you going to have the air conditioner on? Because that reduces your (range). You might have a 100-mile range, but if (the weather) gets very cold or very hot, that range changes. (If) you're driving very fast, the range changes. So there's a big variability.
We should keep in mind that these guys represent major multi-national automakers competing tooth and nail against each other for both conventional and advanced-technology vehicle sales. Each is pursuing a different technological twist to the electrification of volume vehicles, which we all support, and they know that the long-range financial and brand image stakes are huge.

When range-extender EV and PHEV purveyors point out the very real range limitations of battery-only EVs, they are not being "anti-EV." They are merely touting competitive advantages of their products vs. a very tough competitor's, as all automakers do all the time.


Award-winning automotive writer Gary Witzenburg has been writing about automobiles, auto people and the auto industry for 21 years. A former auto engineer, race driver and advanced technology vehicle development manager, his work has appeared in a wide variety of national magazines including The Robb Report, Playboy, Popular Mechanics, Car and Driver, Road & Track, Motor Trend, Autoweek and Automobile Quarterly and has authored eight automotive books. He is currently contributing regularly to Kelley Blue Book (,, Ward's Auto World and Motor Trend's Truck Trend and is a North American Car and Truck of the Year juror.

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