Fuel Economy – Automotive Technology’s New Holy Grail

“They don’t make ‘em like they used to” is a complaint I often hear, and to that I joyously respond, hallelujah!    There’s no denying today’s automobiles lack the beautiful esthetics of the ‘50s and ‘60s.  While today’s cars lack the sheet metal artistry and mechanical simplicity of that period, there’s no denying technology makes 21st Century automobiles better than ever before.

Manufacturers spend countless dollars on research and development to gain the slightest advantage over their competitors, and today, fuel economy is the holy grail of automotive engineers.  “All that technology is a ‘cocktail’ manufacturers have put together, and the competition (among manufacturers today) is in technology”, says Dr. David Checkel, professor emeritus of the University of Alberta’s Department of Mechanical Engineering.  Strict new Corporate Average Fuel Economy standards mandated by the United States are slated to take force in 2016 (requiring a ‘fleet’ average 35.5 miles per U.S. gallon, some 39-percent better than the 25.5 mpg fleet average required in 2007.)  With stringent new fuel economy standards looming, Checkel agrees manufacturers are engaged in a war of engineering brainpower.  The engineering departments of every auto manufacturer are leaving no stone unturned to find every way possible to eke out another fraction of a mile per gallon.

What can consumers expect in automobiles in the next five years?  Checkel lists these main areas where greater fuel efficiencies will be found:  turbocharging; engine downsizing; gasoline direct injection; diesel engines; CVT continuously-variable transmissions; variable displacement engines; and HCCI homogenous charge compression ignition (a form of internal combustion which can be described as a cross between the way gasoline and diesel engines combust fuel.)

Here is a selection of technologies built into new vehicles to improve fuel economy.

Turbocharging.  There’s no replacement for displacement, is a mantra chanted by old school racers, but New Agers shoot back with ‘technology trumps displacement.’  Turbocharging relies on an exhaust gas driven pump to force more air (and fuel) into the engine, giving it the power of a larger engine when demanded and the low fuel consumption of a small engine when power isn’t needed.  Turbocharging will become more widely used – “Everybody’s headed there”, Checkel states.  And consumers are quickly accepting turbo power.  In October, Ford said 41-percent of F-150 pickup truck sales were EcoBoost (turbocharged V-6s), remarkable for a segment where V-8 power was once a ‘must have’.  When matched with computer technology, turbocharging yields astonishing power gains.  Audi, BMW, Chevrolet, Ford, Lincoln, Nissan, Mazda, Porsche, Saab, Volkswagen and Volvo all have turbocharged models in their current lineup.

Lighter weight.  Mazda and Subaru say their new models are expected to be about 100 pounds lighter than the outgoing versions.  Audi’s A8 sedan has an aluminum body for lighter weight, and there’s a trend to save weight by eliminating the temporary spare tire (replacing it with an air compressor and a can of tire sealant) like on the Ford Mustang and Honda Civic.  For the 2013 Escape, Ford says the seats have been slimmed to save weight, and the company recently announced its use of MuCell technology, where CO2 or nitrogen is injected in the plastic molding process, creating ‘air’ cells and lighter weight for parts such as dashboards.  The 2012 Jeep V-6 engine has an aluminum block that is some 90 lbs. lighter than the old cast iron version.

Transmissions.  Transmissions have received considerable attention to increase fuel efficiency.  Six-speed manual transmissions, once reserved for exotic sportscars, are the new norm and standard equipment on the basic Hyunda Accent GLS, for example.  For automatic transmissions, CVT continuously-variable transmissions (which are stepless and have an infinite number of gear ratios) are available on the Nissan Murano, 2012 Subaru Impreza, Lexus CT200h, and Honda Civic Hybrid.  Expect to see more CVT transmissions on lower powered vehicles, says Checkel, because they’re less expensive to manufacture and are more efficient than ‘normal’ automatic transmissions.  On ‘regular’ automatic transmissions, expect more gears; 6-speeds are now common and 7- or 8-speed automatics can be found in Audi, BMW, Chrysler/Dodge, Mercedes-Benz and Volvo.

Automatic Engine Start-Stop.  The easiest way to cut fuel use is to turn off the engine.  AESS is common on hybrid vehicles, but expect wider application.  Under appropriate conditions when the vehicle stops, the gas engine turns off; when the driver lifts their foot off the brake to apply the accelerator, the engine automatically restarts.  The V6 Porsche Panamera has AESS as will the upcoming versions of the BMW 1- and 3-series with four-cylinder engine and manual transmission.

Cylinder deactivation.  Another way to reduce fuel consumption is to ‘shut off’ certain cylinders under low load conditions.  This is called engine variable displacement or cylinder deactivation.  This system is used in Chrysler/Dodge V-8 Hemi, 3.5-litre V-6 Honda Pilots and certain General Motors and Mercedes-Benz vehicles.

GDI.  In Gasoline Direct Injection, engine efficiency is improved by placing fuel injectors in the head and with computer controls, the fuel flow can be regulated with great precision.  With GDI, engines can have very high compression ratios.  Mazda’s new Skyactiv 2.0-litre DOHC 4-cylinder engine, for instance, has a 12:1 compression ratio (13:1 outside North America) and runs on regular fuel as does the new Ford Focus 2.0-litre DOHC GDI engine (rated at 160 horsepower with a 12:1 compression ratio.)  That’s impressive power and fuel economy is remarkable too.  Hyundai, Kia and Mercedes-Benz also have GDI engines.

Aerodynamics.  Lower air resistance means less fuel consumption.  The Ford Focus and Chevrolet Cruze go beyond slick sheet metal by using speed sensitive movable louvres behind the grill to smooth the airflow.

“New technologies enable other technologies”, Checkel says, and that means automobiles will continue to become more powerful and achieve fuel economy ratings once thought impossible.  Whether you’re a performance enthusiast, penny-pinching commuter, or business operator, that sounds like good news.


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