By ditching V-6 engines in favor of improved four-cylinder engines, Hyundai's clearly making fuel economy a chief priority with its 2011 Sonata -- but customers who want the utmost in fuel savings will likely look past the standard sedans and shop the new 2011 Sonata Hybrid, which makes its debut at the 2010 New York auto show.
Contrary to many hybrid variants of existing models, Hyundai has actually made quite a few visual changes to the Sonata Hybrid's exterior. Among the list of equipment unique to the hybrid version of the Sonata are the headlights and taillights, bumper fascias, rocker panels, front grille, 'eco-spoke' wheels, air dam and side sills, badging and paint color. Sure, some of those changes are purely cosmetic, but Hyundai says that many are functional, making the Sonata Hybrid more aerodynamic and lowering its drag coefficient to a slippery 0.25 -- the same as the Toyota Prius.
The 2011 Sonata Hybrid marks the first production use of Hyundai's Hybrid Blue Drive technology -- a proprietary platform that we've seen in prototype form for some time now. As a full parallel hybrid drivetrain, Blue Drive can operate independently on either its 169-horsepower 2.4-liter gasoline engine or its 40-horsepower electric motor, with total overall power listed at 209 horsepower and 195 pound-feet of torque. In sharp contrast to most of competition which employ CVTs for their hybrids, the Sonata Hybrid utilizes the automaker's in-house compact six-speed automatic transmission with electric oil pump, which Hyundai says offers similar economy while retaining a more conventional shift feel that resonates better with customers.
Another key feature the Blue Drive system is its battery technology. Hyundai claims to be the only automaker utilizing lithium-polymer batteries in a production vehicle, the advantages of which are many. According to Hyundai, lithium-polymer batteries offer the same benefits of lithium-ion batteries, but are more robust, lighter, easier to cool, and more easily packaged due to a significantly thinner profile. The automaker further claims that compared to nickel-metal hydride batteries, lithium-polymer batteries are more resistant to changes in temperature, have a slower self-discharge rate, and offer 10 percent greater efficiency with a 40 percent reduction in volume.
Other power-saving tricks have been employed to keep the Sonata Hybrid as efficient as possible. Its Theta II gasoline engine operates on an Atkinson Cycle, making changes to compression and power strokes when the electric motor is operating in unison, conserving energy and boosting fuel economy. Hyundai's Hybrid Power Control management software also features a start/stop system that shuts down the gasoline engine when the vehicle is stationary, automatically restarting it when pressure is reapplied to the throttle.
To help ensure that the Sonata Hybrid is being driven as efficiently as possible, a Hybrid Technology Display is located inside (either on the instrument panel or on the optional navigation display), monitoring which mode the vehicle is being driven in, energy flow inside the vehicle, engine and motor movement, fuel level, battery power level and charge status, and both average and instant mpg.
Much like the gasoline-powered Sonata, Hyundai claims its Sonata Hybrid is a segment leader in many regards, with the lowest curb weight (3457 pounds), most horsepower, and greatest passenger volume (104 cubic feet) of any of its competition from Ford, Nissan, Toyota and Honda. While actual EPA numbers have yet to be released for the Sonata Hybrid, Hyundai is estimating 37/39 city/highway mpg -- figures that place the Sonata right around the top of the pack with Ford's 41/36 mpg Fusion Hybrid. Whether the EPA backs up those figures remains to be seen. Also remaining to be seen is whether cold hard numbers can equate to an all-around better hybrid midsize sedan. For the answer to that question, you'll have to stay tuned.