Hyundai has unveiled its 2011 Sonata Hybrid, which boasts unique approaches in hybrid powertrain design and battery technology. The car debuts Hyundai’s Hybrid Blue Drive system, which will serve as the foundation for the brand’s future hybrid models.

Hybrid Blue Drive is a full parallel hybrid drive system, which can operate on electric motor, gasoline engine, and a combination of the two depending on driving conditions and driver demands. The internal combustion engine used here is the 2.4-litre Theta II operating on the Atkinson Cycle with 169 bhp and 216 Nm of torque. Major driveline and cooling system components have been optimised to reduce friction, while the crankcase has been filled with low friction oil. Also new is start-stop tech and braking regeneration. All these measures combine for 10% better fuel consumption over the standard Theta II engine.

The electric motor is a 30kW unit pushing out 205 Nm of torque. Combined, the system puts out 209 bhp and 265 Nm and the official combined fuel economy figure is 13.5 km/l. The Sonata Hybrid’s EV-only limit is 100 km/h.


Instead of a CVT, Hybrid Blue Drive uses Hyundai’s proprietary 6-speed automatic transmission as found in the new Tucson and Sonata YF. Mods for this application include replacing the torque converter with an electric motor and efficient oil pump. Hyundai says that the decision to not use a CVT is to “provide a more traditional shift feel that is preferred by customers”, not to mention provide better economies of scale for the self-developed gearbox.

The Sonata Hybrid is the first and only car currently using lithium polymer battery technology, which Hyundai says is superior to nickel-metal hydride and lithium-ion tech. LiPo batteries offer 1.7 times more energy density than NiMH and deliver the same power with 20-30% less weight, 40% less volume and 10% better efficiency. Compared to lithium-ion, LiPo is more resistant to physical damage and can handle more charge-discharge cycles before storage capacity begins to degrade. LiPo batteries also offer advantages in thermal robustness and safety, and is cheaper to make.


For the Sonata Hybrid’s look, Hyundai wanted “at-a-glance” differentiation from the standard car, and has succeeded, thanks mainly to the bold hexagonal grille. The light clusters on both ends are also unique, while the bumpers, side sills and wheels have been optimised for aerodynamics.

Full gallery after the jump.

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